Texas Commission on Environmental Quality v. Wilbarger Creek Conservation Alliance, Marilyn Kelinske, Anne Brockenbrough, and Jonathan Beall

ACCEPTED 15-25-00084-CV FIFTEENTH COURT OF APPEALS AUSTIN, TEXAS 10/3/2025 3:01 PM No. 15-25-00084-CV CHRISTOPHER A. PRINE CLERK IN THE FIFTEENTH DISTRICT COURT OF APPEALS FILED IN AUSTIN, TEXAS 15th COURT OF APPEALS AUSTIN, TEXAS 10/3/2025 3:01:36 PM TEXAS COMMISSION ON ENVIRONMENTAL QUALITY, CHRISTOPHER A. PRINE Appellant, Clerk

v.

WILBARGER CREEK CONSERVATION ALLIANCE, MARILYN KELINSKE, ANNE BROCKENBROUGH, and JONATHAN BEALL, Appellees.

On Appeal from the 126th District Court of Travis County, Texas Cause No. D-1-GN-23-004031

BRIEF OF APPELLANT TCEQ

KEN PAXTON AMANDA ATKINSON CAGLE Attorney General of Texas Assistant Attorney General State Bar No. 00783569 BRENT WEBSTER Amanda.Cagle@oag.texas.gov First Assistant Attorney General SARA J. FERRIS RALPH MOLINA Assistant Attorney General Deputy First Assistant Attorney State Bar No. 50511915 General Sara.Ferris@oag.texas.gov

AUSTIN KINGHORN OFFICE OF THE ATTORNEY Deputy Attorney General for Civil GENERAL OF TEXAS Litigation Environmental Protection Division P.O. Box 12548, MC-066 KELLIE E. BILLINGS-RAY Austin, Texas 78711-2548 Chief, Environmental Protection (512) 975-1582 | Fax: (512) 320-0911 Division Attorneys for the Texas Commission on Environmental October 3, 2025 Quality

Oral Argument Requested

IDENTITY OF PARTIES AND COUNSEL

Appellant: Counsel:

Texas Commission on Amanda Atkinson Cagle Environmental Quality Sara J. Ferris OFFICE OF THE ATTORNEY GENERAL OF TEXAS Environmental Protection Division P.O. Box 12548, MC-066 Austin, Texas 78711-2548 (512) 975-1582 | Fax: (512) 320-0911

Appellees: Counsel:

Wilbarger Creek Christopher D. Smith Conservation Alliance, Becky L. Jolin Marilyn Kelinske, Anne SMITH JOLIN PLLC Brockenbrough, and 901 S. Mopac Expressway Jonathan Beall Building 1 Suite 300 Austin, Texas 78746 (512) 659-6912

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TABLE OF CONTENTS

IDENTITY OF PARTIES AND COUNSEL ..................................................... i INDEX OF AUTHORITIES .......................................................................... iv GLOSSARY OF ACRONYMS AND TECHNICAL TERMS ......................... viii STATEMENT OF THE CASE ........................................................................ 1 STATEMENT REGARDING ORAL ARGUMENT......................................... 2 ISSUE PRESENTED ..................................................................................... 2 STATEMENT OF FACTS............................................................................... 3 A. Legal Background: Contested case hearings—the highest level of participatory process afforded in a permitting proceeding—are limited to “affected persons” ...................................................................................... 3 B. Regulatory Background: The Commission’s permitting process includes careful consideration of both the technical aspects of the proposed permit and public comments ................................................................. 4 1. Commission experts independently analyzed and modeled the likely effects of the proposed discharge ........................................................................... 5 2. Appellees participated in this process by filing comments that the Commission considered ..................... 8 3. The Commission considered Appellees’ hearing requests in light of the record, including its staff’s assessment of the likely impact of the permit on the creek and the ED’s analysis and opinions ...................................................... 10 SUMMARY OF THE ARGUMENT.............................................................. 14 STANDARD OF REVIEW ........................................................................... 16 ARGUMENT................................................................................................ 18 I. Texas law requires the Commission to weigh specific information and find requestors likely to be impacted before it may grant a hearing request....................................... 18

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A. The affected person standard reflects the administrative forum by empowering the Commission to utilize its specialized expertise and data when evaluating the required factors ............... 19 B. The standard to be met, as well as specific factors and materials to be considered are set forth by statutes and regulations .................................... 21 C. The burden to establish affectedness rests on the requestor. .................................................................. 24 II. Substantial evidence supports the Commission’s hearing denial because Appellees are not likely to be affected by this permit .............................................................. 25 A. Appellees’ concerns about “contamination” do not establish them as affected persons ........................... 26 B. Appellees’ concerns about plant failures do not establish them as affected persons .................................. 29 C. Appellees’ concerns about algae and low dissolved oxygen do not establish them as affected persons .............................................................. 30 D. Appellees’ distance from the plant and the nature of their allegations further support that they are not likely to be impacted in a manner different from the general public .................................... 34 CONCLUSION AND PRAYER .................................................................... 37 CERTIFICATE OF SERVICE....................................................................... 39 CERTIFICATE OF COMPLIANCE .............................................................. 40 INDEX OF APPENDIX ITEMS (attached).................................................. 41

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INDEX OF AUTHORITIES

Cases Boerne to Bergheim Coal. for Clean Env’t, 657 S.W.3d 382 (Tex. App.—El Paso 2022, no pet.) ............................... 16 City of El Paso v. Pub. Util. Comm’n, 883 S.W.2d 179 (Tex. 1994) ......................................................................17 City of Los Angeles v. Lyons, 461 U.S. 95 (1983) ................................................................................... 28 City of Waco v. Tex. Comm’n on Envtl. Quality, 346 S.W.3d 781 (Tex. App.—Austin 2011) ............................................... 19 Collins v. Tex. Nat. Res. Conservation Comm’n, 94 S.W.3d 876 (Tex. App.—Austin 2002, no pet.) ............................ 24, 29 Dyer v. Tex. Comm’n on Envtl. Quality, 639 S.W.3d 721 (Tex. App.—Austin 2019) aff’d, 646 S.W.3d 498 (Tex. 2022) ...........................................................17 Garcia v. City of Willis, 593 S.W.3d 201 (Tex. 2019)..................................................................... 29 Heat Energy Advanced Tech., Inc. v. W. Dall. Coal. for Envtl. Justice, 962 S.W.2d 288 (Tex. App.—Austin 1998, pet. denied) .......................... 24 Heckman v. Williamson Cnty., 369 S.W.3d 137 (Tex. 2012) ..................................................................... 19 Kaup v. Tex. Workforce Comm’n, 456 S.W.3d 289 (Tex. App.—Houston [1st Dist.] 2014, no pet.) ..............17 Mathews v. Eldridge, 424 U.S. 319 (1976).................................................................................. 20 Mireles v. Tex. Dep’t of Public Safety, 9 S.W.3d 128 (Tex. 1999) ......................................................................... 18 Save Our Springs Alliance, Inc. v. Tex. Comm’n on Envtl. Quality, 713 S.W.3d 308 (Tex. 2025) .................................................................... 18

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Shrimpers & Fishermen of RGV v. Tex. Comm’n on Envtl. Quality, 968 F.3d 419 (5th Cir. 2020) ....................................................... 20, 23, 29 Tex. Comm’n on Envtl. Quality v. City of Aledo, No. 03-13-00113-CV, 2015 WL 4196408 (Tex. App.—Austin July 8, 2015, no pet.) ................................................ 25 Tex. Comm’n on Envtl. Quality v. City of Waco, 413 S.W.3d 409 (Tex. 2013) ............................................................. passim Tex. Comm’n on Envtl. Quality v. San Antonio Bay Estuarine Waterkeeper, 714 S.W.3d 270 (Tex. App.—[15th Dist.] 2025, pet. filed) ................. 24, 25 Tex. Comm’n on Envtl. Quality v. Sierra Club, 455 S.W.3d 228 (Tex. App.—Austin 2014, pet. denied) ......... 16, 21, 23, 30 Tex. Health Facilities Comm’n v. Charter Medical-Dallas, Inc., 665 S.W.2d 446 (Tex. 1984) ..................................................................... 17 Constitutional Provisions & Statutes Tex. Gov’t Code § 2001.171 .......................................................................... 16 Tex. Gov’t Code § 2001.174 ..........................................................................17 Tex. Water Code § 5.115........................................................................ passim Tex. Water Code § 5.115(a) ................................................................... passim Tex. Water Code § 5.115(a-1) ............................................................. 4, 20, 37 Tex. Water Code § 5.115(a-1)(1)(A)-(E) ..................................................15, 22 Tex. Water Code § 5.115(a-1)(1)(B)........................................................ 19, 24 Tex. Water Code § 5.115(a-1)(2)(B) ............................................................. 14 Tex. Water Code § 5.115(b) .......................................................................... 37 Tex. Water Code § 5.221 ............................................................................. viii Tex. Water Code § 5.222 ............................................................................ viii Tex. Water Code § 5.351 .............................................................................. 16

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Tex. Water Code § 5.556 .................................................................... 4, 20, 25 Tex. Water Code § 5.556(c) ..........................................................4, 18, 30, 37 Tex. Water Code Ch. 26 ................................................................................. 4 Tex. Water Code § 26.003 ............................................................................. 4 Tex. Water Code § 26.121 .............................................................................. 4 Rules & Regulations 30 Tex. Admin. Code § 39.419.................................................................... viii 30 Tex. Admin. Code § 39.551 ....................................................................... 9 30 Tex. Admin. Code § 50.117(f) ................................................................... 3 30 Tex. Admin. Code § 55.156 ....................................................................... 9 30 Tex. Admin. Code § 55.201(c)(3)-(5) ..................................................... 13 30 Tex. Admin. Code § 55.201(d) ................................................................ 13 30 Tex. Admin. Code § 55.201(d)(2) ........................................................... 24 30 Tex. Admin. Code § 55.203(c) .......................................................... 23, 25 30 Tex. Admin. Code § 55.203(c)(2) ........................................................... 24 30 Tex. Admin. Code § 55.203(c)(4)-(5) ..................................................... 24 30 Tex. Admin. Code § 55.205 .................................................................... 13 30 Tex. Admin. Code § 55.209 .................................................................... 12 30 Tex. Admin. Code § 305.44(b) ................................................................. 5 30 Tex. Admin. Code § 305.45(a)(6) ............................................................. 5 30 Tex. Admin. Code § 305.45(a)(8) ............................................................. 5 30 Tex. Admin. Code Ch. 307................................................................... 4, 11 30 Tex. Admin. Code § 307.10 .................................................................6, 31

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30 Tex. Admin. Code § 307.2(e) .................................................................. 35 30 Tex. Admin. Code § 307.4(d) ................................................................. 29 30 Tex. Admin. Code Ch. 309 ....................................................................... 4 30 Tex. Admin. Code § 321.34(b) .................................................................. 5 30 Tex. Admin. Code § 321.34(f) ................................................................... 5

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GLOSSARY OF ACRONYMS AND TECHNICAL TERMS

Appellees – Wilbarger Creek Conservation Alliance (WCCA), its President, Jon Beall, its Vice President, Anne Brockenbrough, and its Board Member Marilyn Kelinske, (referenced collectively as WCCA).

Applicant – SWWC Utilities, Inc. AR – Administrative Record. CBOD – Combined Biological Oxygen Demand.

Commission or TCEQ – Texas Commission on Environmental Quality, Appellant in this suit.

CFU – Colony-Forming Unit – Measure of the number of viable bacteria in a sample.

Discharge Point or Outfall – The location where water, run-off, or effluent enters a watercourse (such as a creek or river).

Executive Director or ED – TCEQ’s Executive Director – Oversees the day-to-day operations of the agency, including processing applications for wastewater treatment permits and preparing draft permits and recommendations for the Commission. See Tex. Water Code §§ 5.221-5.222; 30 Tex. Admin. Code § 39.419.

Final Order – Final Order of the Texas Commission on Environmental Quality, signed on May 2, 2023, in TCEQ Docket No. 2023-0370-MWD, concerning the application by SWWC Utilities, Inc. for a new Texas Pollutant Discharge Elimination System Permit No. WQ0016022001.

OPIC – Office of Public Interest Counsel.

SWQM/SWQMIS – Texas Surface Water Quality Monitoring/Texas Surface Water Quality Monitoring Information System or Texas Surface Water Quality Monitoring System.

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STATEMENT OF THE CASE

Nature of the Case: This is an appeal of a final order in a suit for judicial review of a state agency order. In that order, the Texas Commission on Environmental Quality denied Appellees’ requests for a contested case hearing and issued a permit for a new domestic wastewater treatment plant. 1 0F

Trial Court: 126th Judicial District Court, Travis County The Honorable Laurie Eiserloh, presiding by assignment

Trial Court The district court reversed the Commission Disposition: Order, vacated the permit, and remanded to the Commission.

1 The District Court Order, the Commission’s Final Order [RR.AR.31], and the Permit

[RR.AR.29] are Appendix Items 1, 2, and 3. The Clerk’s Record (CR) is cited as “CR at (page).” The Reporter’s Record (RR) is cited as “RR at (page).” The Administrative Record (AR) of the Commission proceeding is cited as “RR.AR.(Item) at (page)” with identifying information in brackets. Items in the Appendix are initially cited with complete information, with subsequent citations referencing the Appendix Item number. The AR was tendered and admitted by the district court as three exhibits: Joint Exhibit 1 (AR Items 1-35); Joint Exhibit 2 (AR Item 46); Defendant’s Exhibit 1 (AR Items 36-45). RR at 5-6, 11.

STATEMENT REGARDING ORAL ARGUMENT

The Commission respectfully requests oral argument. This case involves a complex regulatory permitting process. Oral argument may help clarify and explain the administrative record and regulatory scheme supporting the Commission’s Order.

ISSUE PRESENTED

Was it an abuse of discretion for the Commission to evaluate Appellees’ hearing requests in light of the materials before it—including its expert staff’s assessment of the creek, their assessment of the likely impacts of this discharge on the creek, and the analysis and opinions of its Executive Director (ED) that this discharge would not impact Appellees in a manner different from the general public—and to find that Appellees were not entitled to a contested case hearing?

STATEMENT OF FACTS

This case concerns the Commission’s denial of requests for a contested case hearing and issuance of a permit to construct and operate a new domestic wastewater treatment plant for a subdivision in the Manor area of Travis County. Appx.2 [Commission Final Order].

A. Legal Background: Contested case hearings—the highest level of participatory process afforded in a permitting proceeding—are limited to “affected persons”

Contested case hearings are the highest level of participatory process available under Texas law in a permitting proceeding. But they are resource-intensive for applicants, agencies, and protestants; and can also greatly increase the overall timeline for important infrastructure projects throughout the State. Tex. Comm’n on Envtl. Quality v. City of Waco, 413 S.W.3d 409, 410 (Tex. 2013) (City of Waco). Accordingly, the Legislature has not made this level of process available to everyone.

The process available to everyone is the comment process. The Commission must consider all comments. 30 Tex. Admin. Code § 50.117(f). But contested case hearings are only available to “affected persons.” Tex. Water Code § 5.115. The Legislature has specifically enumerated the factors— and the materials—the Commission is to consider in determining whether a requestor is an “affected person.” The Legislature made the Commission the *4 gatekeeper. It gave the Commission the authority—and the discretion—to evaluate the specified materials and to determine whether or not a requestor has met this threshold. Tex. Water Code §§ 5.556, 5.115(a), (a-1).

B. Regulatory Background: The Commission’s permitting process includes careful consideration of both the technical aspects of the proposed permit and public comments

The Commission is charged to protect water quality while also providing for wastewater needs and the use and enjoyment of Texas waters by all Texans. Tex. Water Code Ch. 26; 30 Tex. Admin. Code Ch. 307 and 309. Under Texas Water Code § 26.121, no person may discharge wastewater into water in the state except as authorized by a Commission Texas Pollutant Discharge Elimination System (TPDES) permit. The Commission reviews potential TPDES permits and their possible effects on receiving waters as part of its charge to protect those waters for the general public. Tex. Water Code § 26.003; see also Tex. Water Code Ch. 26, §§ 5.556(c), 5.115; 30 Tex. Admin. Code Ch. 307 and 309. As part of that process, the Commission evaluates potential impacts holistically, with a careful eye to cumulative effects that might be caused when there are multiple discharges into a waterway. See, e.g. RR.AR.9 at 1 [Water Quality Modeling Memo]; RR.AR.36 at 5-6, 10-11 [Water Quality Modeling Memo Working Papers]. 2 This is 1F 2 The Water Quality Modeling Memo and Water Quality Modeling Memo Working Papers are Appendix Items 13 and 14. *5 different from what requestors are required to establish to obtain a contested case hearing, which is that a permit will harm them in particular, that they have “a personal justiciable interest related to a legal right” “affected by” the permit that is not “common to members of the general public.” Tex. Water Code § 5.115(a).

1. Commission experts independently analyzed and modeled the likely effects of the proposed discharge

The application process includes a thorough review by Commission staff and requires detailed information be provided by the applicant. See Form TCEQ-10053—Domestic Wastewater Permit Application (May 5, 2021). A permit application “amounts to an affidavit with expert reports attached.” City of Waco, 413 S.W.3d at 421; see also 30 Tex. Admin. Code §§ 305.44(b), 321.34(b) (affidavit required); id. §§ 305.45(a)(6), (8), 321.34(f) (maps and technical reports must be prepared by a licensed professional engineer, a licensed professional geoscientist, or other qualified person).

The application in this case consisted of over 100 pages of information, and included both the requisite affidavit as well as a detailed engineering report sealed by a professional engineer that provided plans and specifications for the proposed specific technology-based treatment methods *6 and showed that the treated effluent would meet the proposed limitations. RR.AR.1 at 75, 83 [Permit App.].

Commission staff scrutinize and analyze the technical aspects of the application, utilizing not only data provided by the applicant, but also data from the Commission’s own extensive water quality monitoring and permitting databases, including the Texas Surface Water Quality Monitoring Information System (or SWQMIS), a constantly-updated database of water quality sample results from across the state. RR.AR.20, at 8-9 [Executive

Director’s Response to Comments]; 3 RR.AR.44 [Surface Water Quality 2F

Monitoring System Map]. 4 SWQMIS data is compiled into the Texas 3F

Integrated Report of Surface Water Quality (Integrated Report), which assesses surface water quality and assigns each waterway to a “use category”

based on that data as compared to water quality standards. 5 RR.AR.42-43 4F

[Integrated Reports 2020, 2022 (excerpts)]. 6 Wilbarger Creek supports 5F

High aquatic life and Colorado River Segment 1434 (into which it flows) supports Exceptional aquatic life. 30 Tex. Admin. Code § 307.10, Appendices A, C, D (excerpts) at 3, 7 [Texas Surface Water Quality Standards: Site-

3 The Executive Director’s Response to Comments is Appendix Item 6. 4 The Surface Water Quality Monitoring System Map is Appendix Item 15. 5 So if a waterway is assigned to a “high” use category, that means that the sample data

results correspond to “high” water quality standards. 6 The Integrated Reports are Appendix Items 16 and 17.

Specific Uses and Criteria]; 7 see also Appx.16, 17 [Integrated Report 2020, 6F

2022 (excerpts)].

Dr. M. A. Wallace, PhD, of the Water Quality Assessment Standards Implementation Team, analyzed this permit application in light of data about the receiving waters and applicable standards. Her report concluded that the proposed limits on nutrients such as Total Phosphorus (associated with algae) and on E. coli bacteria (which meets EPA requirements for swimming) would be sufficiently protective to maintain the high quality of the water in Wilbarger Creek. RR.AR.7 [Standards Implementation Memo]; RR.AR.37 at 1-2 [Standards Implementation Memo Working Papers]; Appx.3 at 3 [Permit]; RR.AR.39 at 24 [Implementation Procedures]. 8 7F

Josi Robertson, of the Commission’s Water Quality Assessment Team, evaluated the in-stream effects of the proposed discharge across the entire receiving water to assess and prevent potential bio-accumulation harms. The model she developed included inputs from every permitted facility that discharges into Wilbarger Creek, and assessed impacts on each and every section of the creek by “reaches,” which are defined segments of the creek that extend all the way to the Colorado River. Appx.13 at 1 [Water Quality 7 The excerpted Texas Surface Water Standards is Appendix Item 18. (Clearer version

available at: Secretary of State’s website). 8 The Standards Implementation Memo, Standards Implementation Memo Working

Papers, and Implementation Procedures are Appendix Items 10-12. *8 Modeling Memo]; Appx.14 at 5-6, 10-11 [Water Quality Modeling Memo Working Papers]. Her analysis found that the proposed permit effluent limits for all flow phases of the proposed permit would ensure that in-stream dissolved oxygen levels in Wilbarger Creek would continue to support high level aquatic life. Appx.13 at 1 [Water Quality Modeling Memo].

This process took time—agency staff spent almost a year evaluating and analyzing these factors before the Executive Director issued her preliminary decision recommending the draft permit. See, RR-AR.1 at 1 [Permit App.]; RR-AR.12 at 7 [Executive Director’s Technical Summary and

Preliminary Decision]. 9 The draft permit reflected the Executive Director’s 8F

independent determination that the proposed permitted discharge will meet all applicable water quality standards—in this case—that the discharge will not degrade the water quality in Wilbarger Creek or the Colorado River and that “[e]xisting uses will be maintained and protected.” RR.AR.12 at 4.

2. Appellees participated in this process by filing comments that the Commission considered

Texas’s permitting process includes provisions for public participation and for multiple rounds of notices to the public prior to a contested case determination: the first when the Executive Director finds the application to 9 The Executive Director’s Technical Summary and Preliminary Decision is Appendix Item 5. *9 be administratively complete; and the second, after technical review, when the Executive Director issues a preliminary decision on whether to issue the draft permit. 30 Tex. Admin. Code § 39.551.

After the Commission’s Executive Director (ED) determined that the application was administratively complete, SWWC posted the first notice and published it in area newspapers on December 16 and 17, 2021. RR.AR.14-15. The First Notice informed persons in the area of basic details about the application, that the Commission’s ED would be conducting a technical review of the application, and could prepare a draft permit and issue a preliminary decision, and gave instructions for how to submit public comments, request a public meeting, and request a contested case hearing. RR.AR.15 at 6; see also 30 Tex. Admin. Code § 55.156.

Since the ED’s technical review, discussed above, found the application met statutory requirements for issuance, the ED issued a preliminary decision and statement of basis/technical summary, along with a draft permit, on May 9, 2022. Appx.5. This triggered the second round of public notice, the Notice of Application and Preliminary Decision, which was posted and also published in area newspapers on June 30 and July 1, 2022.

RR.AR.19.

Only three people, the three individual Appellees here, filed public comments. They did so individually and on behalf of the Wilbarger Creek Conservation Alliance (WCCA), of which they are all board members.

RR.AR.34 at 10, 14 [Public Comments]. 10 Together, they asserted their 9F

interests as owners of property located approximately 5 miles downstream of the outfall. Id. at 11. They contended their interests would be harmed because:

• • The creek is already “impaired” by algae and bacteria and low oxygen levels caused by discharges from other permitted facilities; such that they fear to swim in or let their livestock drink from the creek and they hear fewer frogs than they used to; and
• • Any additional discharge will make those conditions worse; and
• • “All plants fail at some point” so this plant will fail and discharge untreated effluent.

See id. at 7, 11, 14, 33, 34-35, 37. Appellees provided two photographs to support their algae impairment claims. RR.AR.46 [Requestors’ Photos].

3. The Commission considered Appellees’ hearing requests in light of the record, including its staff’s assessment of the likely impact of the permit on the creek and the ED’s analysis and opinions

The ED responded to the public comments, addressing each of Appellees’ concerns with detailed analysis and opinions, supported by 10 The Public Comments, which in this case also contain Appellees’ Hearing Requests, are Appendix Item 8. Requestors’ Photos are Appendix Item 9. *11 references to Commission data. Appx.6 [ED’s Resp to Comments]. She disputed WCCA’s contentions that the creek is impaired by other permitted discharges, and supported her opinion by reference to the fact that the Integrated Report does not show Wilbarger Creek as impaired. Id. at 8. She further explained that the Commission conducts an “updated assessment” of the creek “every two years, comparing observed water quality from sampling data against various applicable water quality criteria,” and that the Commission has data collected “at an active SWQM Station approximately 2.25 miles downstream” of the proposed plant—a location upstream of Appellees and between them and the plant—as well as other active stations “further upstream and downstream on Wilbarger Creek, in which current water quality data is being collected.” Id. at 8-9; see also Appx.15 [SWQM Map (Wilbarger Creek is 1434D)]. She also noted that the Texas Surface Water Quality Standards, which are based on the Integrated Report, show Wilbarger Creek as having High Aquatic Life Use with a dissolved oxygen level that supports that high aquatic life use. Id. at 6, 8-9; Appx.18 [Texas Surface Water Quality Standards].

The ED also addressed Appellees’ concerns that this permit would make the water worse, explaining that the standards in the proposed permit were developed to protect aquatic life and human health and “established to *12 be protective.” Id. at 5. She further noted that “The effluent limits in the draft permit are set to maintain and protect the existing instream uses,” referencing limits on both bacteria and algae-related nutrients. Id. at 6, 3. She also discussed the analysis and reviews conducted by Dr. Wallace and the modeling done by Ms. Richardson, including a site-specific nutrient screening to address algae-related concerns, as well as the Tier 1 and Tier 2 antidegradation reviews, and that the reports concluded that “Existing uses will be maintained and protected.” Id. at 6. She further observed that the proposed facility has safeguards in place, including alternate power sources and standby generators, to prevent the discharge of untreated waste during electrical power failures, and that the any discharge of untreated waste would be a violation of the permit. Id. at 9.

Commission regulations provide for the ED to separately analyze requests for contested case hearings after the public comment period expires. 30 Tex. Admin. Code § 55.209. In her Response to Appellees’ hearing requests, the ED integrated the requisite information from Appellees regarding their location and distance relative to the proposed facility, with the analysis and opinions of Commission staff, the application process, and the Response to Comments, and offered her opinion on the likelihood that Appellees would be affected by the proposed permit. RR-AR.38 [ED’s

Response to Hearing Requests]. 11 She analyzed the regulatory factors such 10F

as whether a reasonable relationship exists between the interest claimed and the permit at issue, the likely impact of the permit on the health and safety of each requestor and the likely impact of the permit on each requestor’s use of their property or of the creek. See e.g. 30 Tex. Admin. Code §§ 55.201(c)(3)-(5), (d), 55.205. The ED observed that as to all Appellees, the intervening distance between the outfall and their property made it unlikely that they would be impacted by the permit in any way different from the general public. RR-AR.38 at 7. The Office of Public Interest Counsel (OPIC), a statutorily-created office within the agency whose role is to protect the public interest in all agency matters, concurred, explaining that the distance “diminishes any likelihood that the regulated activity will impact [Appellees’] health, safety, or use of property.” RR.AR.24 at 6-7 [OPIC’s Response to Requests for Hearing].

The Commission considers requests for contested case hearings during open meetings and did so in this case on April 26, 2023. Appx.2 at 1 [Comm’n Final Order]. At that meeting, the Commissioners discussed and addressed Appellees’ representations that they would be harmed, and explained why they did not find them convincing in the specific factual context of this 11 The ED’s Response to Hearing Requests is Appendix Item 7.

proposed permit. RR.AR.35 [Recording of Open Meeting]. 12 On May 2, 11F

2023, the Commission issued a written Order denying Appellees’ hearing requests, adopting the ED’s response to comments, and issuing the permit. Appx.2 [Comm’n Order], Appx.6 [ED’s Resp to Comments]. Appellees’ subsequent motion for rehearing and amended and restated motion for rehearing were denied by operation of law. RR.AR.32, 33. This suit followed.

SUMMARY OF THE ARGUMENT

Opposing SWWC’s permit application, Appellees filed public comments, which the Commission considered and responded to. But Appellees also sought a contested case hearing, which the Commission denied, because it did not find Appellees likely to be affected by this permit. The Commission did exactly what the Legislature has charged it to do—not hold a hearing unless the requestor is an affected person. Tex. Water Code § 5.115(a-1)(2)(B). A contested case hearing is a statutorily-created process; and access to one is similarly statutorily-defined. The Water Code sets forth in detail that the Commission is to weigh and evaluate specific materials and factors in order to determine whether a requestor is likely to be impacted by a permit in a manner different from the general public. 12 CR 190-193. An unofficial but sworn Transcript of RR-AR.35 [Recording of Open Meeting] is Appendix Item 4.

The Commission is charged to use its particular expertise when it evaluates whether a requestor is affected, and to do so in light of the application review process that has already taken place. By statute, the Commission considers not only the application and associated supporting materials, but also whether the application meets the statutory requirements for issuance, as well as, specifically, the opinions and analysis of the Executive Director, and any other expert reports, opinions, or data submitted to the Commission by the ED or others (including requestors). Tex. Water Code §§ 5.115(a), (a-1)(1)(A)-(E).

The Commission considered these materials when determining if the statutory factors—which include the likelihood that Appellees’ property, their use of their property, or their use of Wilbarger Creek, would be impacted by this permit in a manner different from the general public—and found that the factors were not satisfied. Appellees asserted that Wilbarger Creek was impaired and contaminated by existing permitted discharges, and that this was injuring them and that they would necessarily be harmed more by this new permit. But their assertions were contravened by other data, which showed that Wilbarger Creek is neither contaminated nor impaired. The Commission weighed and evaluated Appellees’ locations, 3-5 miles downstream, in light of information about the creek, other discharges’ *16 impacts on the creek, and its expert evaluation of this particular permit’s likely impact on the creek. Moreover, the Executive Director provided the Commission with her analysis and opinion that Appellees would not be impacted by this permit in any manner different from the general public. Appellees’ likely injury assertions were simply not credible to the Commission—which is the fact-finder charged to weigh the materials before it and to make this determination. The Commission’s determination is reasonable and supported by substantial evidence and should be affirmed.

STANDARD OF REVIEW

Courts review a “TCEQ determination regarding affected-person status for an abuse of discretion.” Tex. Comm’n on Envtl. Quality v. Sierra Club, 455 S.W.3d 228, 235 (Tex. App.—Austin 2014, pet. denied) (Sierra Club); see also City of Waco, 413 S.W.3d at 411, 420, 424. Even when, as here, the Commission’s decision was not made in an adjudicatory, contested-case format, the standard of review is substantial evidence. Tex. Water Code § 5.351; Tex. Gov’t Code § 2001.171; Boerne to Bergheim Coal. for Clean Env’t, 657 S.W.3d 382, 390 (Tex. App.—El Paso 2022, no pet.); City of Waco, 413 S.W.3d at 424-425. Under this standard, “a court may not substitute its judgment for that of the agency” but:

(1) may affirm the agency decision in whole or in part; and

(2) shall reverse or remand the case for further proceedings if substantial rights of the appellant have been prejudiced because the administrative findings, inferences, conclusions, or decisions are: (A) in violation of a constitutional or statutory provision; (B) in excess of the agency’s statutory authority; (C) made through unlawful procedure; (D) affected by other error of law; (E) not reasonably supported by substantial evidence considering the reliable and probative evidence in the record as a whole; or (F) arbitrary or capricious or characterized by abuse of discretion or clearly unwarranted exercise of discretion.

Tex. Gov’t Code § 2001.174. The Commission’s order is presumed to be valid and supported by substantial evidence and Appellees bear the burden of proving otherwise. Dyer v. Tex. Comm’n on Envtl. Quality, 639 S.W.3d 721, 731 (Tex. App.—Austin 2019), aff’d, 646 S.W.3d 498 (Tex. 2022).

Under the substantial evidence rule, the burden is on … the party who seeks to set aside the [agency] ruling—to demonstrate that less than substantial evidence supports the decision.

Kaup v. Texas Workforce Comm’n, 456 S.W.3d 289, 294 (Tex. App.— Houston [1st Dist.] 2014, no pet.).

The question before the Court is not whether the Commission reached the correct conclusions, but “whether some reasonable basis exists in the record for the action taken by the agency.” Tex. Health Facilities Comm’n v. Charter Medical-Dallas, Inc., 665 S.W.2d 446, 452-453 (Tex. 1984); see also City of El Paso v. Pub. Util. Comm’n, 883 S.W.2d 179, 185 (Tex. 1994). A *18 reviewing court is not bound by the reasons given by an agency in its order, provided there is a valid basis for the action taken by the agency. Id.

So long as the agency’s findings are supported by more than a mere scintilla of evidence in the record as a whole, even when the evidence is conflicting, or preponderates against the agency’s decision, the agency decision must be upheld. Mireles v. Tex. Dep’t of Public Safety, 9 S.W.3d 128, 131 (Tex. 1999). Under the APA, a reviewing court “may not substitute its judgment for the judgment of the state agency on the weight of the evidence” — the court may not reweigh the evidence. Save Our Springs Alliance, Inc. v. Texas Comm’n on Envtl. Quality, 713 S.W.3d 308, 320 (Tex. 2025) (internal citations omitted).

ARGUMENT

I. Texas law requires the Commission to weigh specific information and find requestors likely to be impacted before it may grant a hearing request

The Legislature has prohibited the Commission from granting a contested case hearing unless it has first determined that the requestor is an “affected person” as defined by statute. “The commission may not grant a request for a contested-case hearing unless the commission determines that the request was filed by an affected person as defined by Section 5.115.” Tex. Water Code § 5.556(c). In determining whether a person is an “affected *19 person,” defined as someone “who has a personal justiciable interest ... affected by the administrative hearing,” the Commission considers and weighs factors such as whether the permit meets requirements for issuance, the materials in the administrative record, and the Executive Director’s opinions and analysis when it evaluates “the likely impact of regulated activity on the health, safety, and use of the property of the hearing requestor.” Tex. Water Code §§ 5.115(a), 5.115(a-1)(1)(B).

A. The affected person standard reflects the administrative forum by empowering the Commission to utilize its specialized expertise and data when evaluating the required factors

The “affected person” standard draws upon jurisprudential standing principles. It requires “a concrete injury to the plaintiff and a real controversy between the parties that will be resolved” by the decision-maker. See Heckman v. Williamson Cnty., 369 S.W.3d 137, 154 (Tex. 2012). A requestor must establish: an ‘injury in fact;’ that is ‘fairly traceable’ to the issuance of the permit as proposed (and not attributable to causes unrelated to the permit); and it must be likely that the injury will be redressed by a favorable decision regarding the proposed permit. City of Waco v. Texas Comm’n on Envtl. Quality, 346 S.W.3d 781, 802 (Tex. App.—Austin 2011) reversed on other grounds, City of Waco, 413 S.W.3d 409 (Tex. 2013).

But although the affected person factors for entitlement to an administrative contested case hearing are based on standing principles, “there are also key differences” in the process and in the factors for making this determination. Shrimpers & Fishermen of RGV v. Tex. Comm’n on Envtl. Quality, 968 F.3d 419, 422 (5th Cir. 2020). This is because:

The ultimate balance involves a determination as to when, under our constitutional system, judicial-type procedures must be imposed upon administrative action to assure fairness … differences in the origin and function of administrative agencies preclude wholesale transplantation of the rules of procedure, trial and review which have evolved from the history and experience of courts.

Mathews v. Eldridge, 424 U.S. 319, 348–49 (1976) (emphasis added). The administrative action at issue here is statutorily-created—a permitting proceeding—and requestors must establish that they are affected persons under the statutory standard to establish their entitlement to the judicial-type procedure of a contested case. See Tex. Water Code §§ 5.556, 5.115.

In 2015, the Texas Legislature amended the Water Code to sharply distinguish how the Commission determines affectedness for the purpose of entitlement to a contested case hearing on a proposed permit from how a court determines standing to maintain a case in court. See Tex. Water Code § 5.115(a-1); Shrimpers & Fishermen of RGV v. Tex. Comm’n on Envtl. Quality, 968 F.3d at 422. In particular, it added new language that *21 authorized the Commission to consider factors and materials that would not ordinarily be considered by a court determining standing. The Commission is charged to rely upon not only the materials in the administrative record, but also its Executive Director’s opinions based on those materials. Indeed, Water Code § 5.115(a-1) specifically authorizes the Commission to consider:

• • the merits of the underlying application, including whether or not the application meets the requirements for permit issuance;
• • the analysis and opinions of the ED; and
• • any other expert reports, opinions, or data submitted to the Commission by the ED or others, including hearing requestors.

“In making a decision regarding affected-person status, TCEQ enjoys the discretion to weigh and resolve matters that may go to the merits of the underlying application, including the likely impact the regulated activity ... will have.” Sierra Club, 455 S.W.3d at 235.

B. The standard to be met, as well as specific factors and materials to be considered are set forth by statutes and regulations

The Water Code makes clear that the Commission is to utilize its environmental subject matter expertise when it determines whether or not a requestor is an affected person. The Legislature expressly directed the Commission to adopt required factors for determining whether persons are *22 affected, and at the same time, enumerated materials and other considerations upon which the Commission may rely:

(A) the merits of the underlying application, including whether the application meets the requirements for permit issuance;

(B) the likely impact of regulated activity on the health, safety, and use of the property of the hearing requestor;

(C) the administrative record, including the permit application and any supporting documentation;

(D) the analysis and opinions of the executive director; and

(E) any other expert reports, affidavits, opinions, or data submitted on or before any applicable deadline to the commission by the ED, the applicant, or a hearing requestor.

Tex. Water Code § 5.115(a-1)(1)(A)-(E).

The Commission has promulgated rules that delineate the factors relevant to an affected person determination:

(1) whether the interest claimed is one protected by the law under which the application will be considered;

(2) distance restrictions or other limitations imposed by law on the affected interest;

(3) whether a reasonable relationship exists between the interest claimed and the activity regulated;

(4) likely impact of the regulated activity on the health and safety of the person, and on the use of property of the person; and

(5) likely impact of the regulated activity on use of the impacted natural resource by the person.

30 Tex. Admin. Code § 55.203(c). Thus, the Commission determines whether or not a permitted discharge is likely to impact a requestor’s interest (health, safety, use of property, use of the natural resource) by considering the requestor’s expressed basis for affectedness in light of information gathered through the application process, including the requestor’s location, staff experts’ analysis and opinions of the discharge’s likely effects on the receiving waters, and whether the proposed permit meets statutory standards, as well as the separately identified “analysis and opinions of the executive director.” Tex. Water Code § 5.115; Shrimpers & Fishermen of RGV, 968 F.3d at 422. Courts have noted that this means the Commission may weigh and resolve facts, even including facts that “may go to the merits of the underlying application,” when it decides whether requestors are affected persons. Sierra Club, 455 S.W.3d at 235. The Commission evaluates a requestor’s asserted interest and injuries in light of such materials and considerations.

There is no presumption that a permitted discharge will harm requestors. Indeed, the opposite is true. As one court observed “[w]hile the environmental damage and nuisance that Collins predicts would surely deprive him of his valuable property rights, we note that the permit does not authorize such failures.” Collins v. Tex. Nat. Res. Conservation Comm’n, 94 *24 S.W.3d 876, 883 (Tex. App.—Austin 2002, no pet.) (emphasis in original). It affirmed the Commission’s decision to not grant Collins a contested case hearing despite his assertions of harm. Id. When making an affected person determination, the Commission must presume the facility will be operated in compliance with permit terms. Id.; see also Tex. Water Code § 5.115(a-1)(1)(B) (Commission must consider likely impact of the regulated activity); 30 Tex. Admin. Code § 55.203(c)(4)-(5).

C. The burden to establish affectedness rests on the requestor.

Persons seeking a contested case hearing must provide their location and distance relative to the proposed facility, identify their personal justiciable interest, and explain how that interest will be adversely affected in a manner not common to the general public. 30 Tex. Admin. Code § 55.201(d)(2); see also § 55.203(c)(2). The requestor “must show that a concrete, particularized, actual or imminent injury faces him or her due to the decision; a hypothetical or speculative injury is not enough.” Tex. Comm’n on Envtl. Quality v. San Antonio Bay Estuarine Waterkeeper, 714 S.W.3d 270, 284 (Tex. App.—[15th Dist.] 2025, pet. filed) (SA Bay); see also Heat Energy Advanced Tech., Inc. v. W. Dall. Coal. for Envtl. Justice, 962 S.W.2d 288, 295 (Tex. App.—Austin 1998, pet. denied).

“A person seeking to be admitted as a party has the burden.” SA Bay, 714 S.W.3d at 284; see also Texas Comm’n on Envtl. Quality v. City of Aledo, No. 03-13-00113-CV, 2015 WL 4196408, at *4 (Tex. App.—Austin July 8, 2015, no pet.) (“applicable Commission rules and Water Code sections squarely place[] that burden of a showing on the requesting person”). Requestors bear the burden to establish that they will be injured in a matter different from the general public; it is not anyone else’s burden to establish requestors will not be.

II. Substantial evidence supports the Commission’s hearing denial because Appellees are not likely to be affected by this permit

The Legislature gave the Commission the tools and discretion to evaluate the materials and factual assertions before it in order to determine whether requestors have articulated a personal justiciable interest that is likely to be impacted such that they are “affected persons” entitled to the process of a contested case hearing on a permit. Tex. Water Code §§ 5.556, 5.115. The Commission exercised that discretion here using the materials at hand. It evaluated Appellees’ contentions that their interests were likely to be impacted by the permitted discharge in light of the other materials before it in accordance with Tex. Water Code § 5.115 and 30 Tex. Admin. Code § 55.203(c).

The rules require the Commission to consider the likely impact of the regulated activity on Appellees. This includes of course, impacts to Appellees’ property, their use of their property, and their use of the creek. Appellees asserted injuries to their property interests as owners of land 3-5 miles downstream from the outfall, making what was essentially an injury per se argument—one that didn’t focus on the permit at issue in particular—but instead generally alleged that the water quality in the creek was bad, which they attributed to other permitted discharges—and that therefore this permitted discharge would necessarily harm them. The problem, though, is that the Commission is charged to weigh the materials before it—not to take Appellees’ contentions as true—and many of the materials before it not only contravened Appellees’ contentions, they also indicated that there is no reasonable relationship between the harms Appellees asserted and the permitted discharge.

A. Appellees’ concerns about “contamination” do not establish them as affected persons

Appellees articulated a variety of concerns related to the purported contamination of the creek, including that they fear to swim in the creek and that they do not let their livestock drink from it because of their concerns that the creek is contaminated and unsafe for those activities. RR-AR.34 at 10, 33-35. Appellees’ only rationale for this supposed contamination was that the *27 creek used to be intermittently dry, but now runs year-round and so is “100% effluent.” But this does not establish an injury. The creek indisputably contains treated wastewater, but it is treated. Indeed, the whole purpose of the Commission’s careful analysis of any permit application, including this one, is to ensure that existing uses of the waterway are protected.

Appellees’ allegations attempted to supplant evidence (sample results and Commission assessments) with assumptions about treated effluent. But the Commission had before it the Texas Surface Water Quality Monitoring Standards—Site-Specific Uses and Criteria, and its Integrated Reports from both 2020 and 2022, which are based on actual sample results from the Commission’s Surface Water Quality Monitoring System. Appx.10 at 1 [Standards Implementation Memo]; Appx.11 at 1 [Standards Implementation Memo Working Papers]; Appx.17 [Texas Surface Water Quality Standards]. That data shows that Wilbarger Creek supports high aquatic life use and is by no means “impaired” or contaminated. Appx.16 [Integrated Report 2020]; Appx.17 [Integrated Report 2022]; Appx.17 at 3, 7 [Texas Surface Water Quality Standards].

Moreover, the ED’s staff analyses verify that the treatment limits required by this permit ensure both that existing uses would be maintained, and that those high-quality waters would not be degraded. Appx.10 at 1 *28 [Standards Implementation Memo]; Appx.11 at 1 [Standards Implementation Memo Working Papers]; Appx.13 at 1 [Water Quality Modeling Memo]; Appx.14 at 1 [Water Quality Modeling Memo Working Papers]. And since Wilbarger Creek discharges into Colorado River Segment 1434, the permit’s limits are designed to meet even higher standards, those applicable to water that supports exceptional aquatic life uses. Appx.10 at 1 [Standards Implementation Memo]. Indeed, the permit’s limit for E. coli bacteria is 126 CFUs, which meets EPA requirements for swimming. Appx.3 at 3 [Permit]; Appx.12 at 24 [Standards Implementation Procedures]. Appellees’ fears are subjective and contravened by scientific data and the ED’s analysis. Their fear does not establish affectedness. See City of Los Angeles v. Lyons, 461 U.S. 95, 107 & n.8 (1983) (Subjective apprehensions are not sufficient to establish standing).

Evaluating this information, along with Appellees’ locations, approximately three to five miles downstream, the Executive Director concluded that Appellees are not likely to be impacted by the permit. Appx.7 at 6-8 [ED’s Resp to Hrg Req]; id. at 14 [map showing relative locations]. In short, the Commission properly determined, based on the evidence before it, that Appellees’ contamination fears failed to meet the threshold for affectedness.

B. Appellees’ concerns about plant failures do not establish them as affected persons

Appellees also alleged that treatment plant malfunctions would occur because of power outages and mechanical failures and that this would cause the plant to exceed its permit limits. Appx.8 at 7 [Comments]. But these are all hypothetical events. They are not actual or certainly impending, nor are they traceable to the proposed permit, which does not authorize operating in that manner. Appx.3 [Permit]; Appx.6 at 9 [ED’s Resp to Comments]. Both the permit and the Commission’s rules prohibit untreated discharges and toxic conditions. See 30 Tex. Admin. Code § 307.4(d); Appx.6 at 7 [ED’s Resp to Comments]; Appx.3 at 5 [Permit].

Appellees’ assumption that the permittee will violate its permit is the opposite of the legal standard. Speculative events not authorized by a permit do not establish affectedness because the standard presumes activities will be conducted within the law. Garcia v. City of Willis, 593 S.W.3d 201, 207 (Tex. 2019); Collins, 94 S.W.3d at 883. In addition, Appellees’ “what if the plant fails” concerns are purely conjectural. They do not meet the standard because injury for affected person status must be concrete and particularized, not conjectural, contingent, or hypothetical. Shrimpers & Fishermen of RGV, 968 F.3d at 424.

In addition, the Commission had before it competent evidence that the engineers who designed the plant had already addressed such concerns. The Application’s engineering report details features for overflow prevention. RR.AR.1 at 83 [Permit Application]. These include an emergency generator, set to “start automatically in the event of a failure,” and an automatic alarm dialer system that notifies the operator and others in the event of “a power outage, chlorine leak, or lift station high water level.” Id.; see also Appx.3 at 12 [Permit] (requiring operations in accordance with Application). And the Applicant’s compliance history is Satisfactory, with a rating of 5.37 on a scale where 0 is best and 55 is worst. RR.AR 26 at 1 [Compliance History Report]; RR.AR.45 at 2 [Compliance History Basics].

Appellees’ concerns about possible future violations were not “certainly impending,” or even reasonably related to this permit and were contravened by substantial evidence. The Commission’s denial of the hearing request was reasonable because Appellees failed to satisfy the applicable factors under 30 Tex. Admin. Code § 55.203(a). See Tex. Water Code § 5.556(c); Sierra Club, 455 S.W.3d at 240.

C. Appellees’ concerns about algae and low dissolved oxygen do not establish them as affected persons

Appellees also alleged concerns related to algae, referencing an algae bloom that purportedly occurred in 2022, and complaining that the creek is *31 generally cloudy. Appx.8 at 11, 14, 34 [Comments]; Appx.9 [Photos]. Similarly, they alleged that a youth group had, at some point, tested the water in the creek and told them that the water’s dissolved oxygen levels were low and that this meant the creek is impaired. Appx.8 at 13-14; 28-29.

But the Commission had contravening evidence before it (not to mention that a second-hand account of a youth’s verbal assessment of the creek as impaired at an unknown point in time lacked credibility). The Commission evaluates waterways based on test results from samples and has, based on those samples, found that Wilbarger Creek supports high aquatic life use, has a 5.0 mg/L dissolved oxygen level, and is by no means “impaired.” Appx.16,17 [Integrated Report 2020, 2022 (excerpts)]; Appx.18 at 3, 7 [Texas Surface Water Quality Standards].

Moreover, Dr. Wallace’s and Ms. Robertson’s reports indicate that the treatment limits required by this permit would ensure that existing uses would be maintained—and that the high and exceptional quality waters of Wilbarger Creek and the Colorado River would not be degraded. Indeed, Dr. Wallace’s report specifically addressed concerns regarding “eutrophication,” which is the process in which a water body becomes overly enriched with

nutrients leading to a harmful increase in the production of algae. 13 She 12F

13 U.S. Geological Survey definition, https://www.usgs.gov/centers/wetland-and- aquatic-research-center/science/science-topics/eutrophication.

performed a site-specific nutrient screening to ensure the permit protects the high quality of the receiving waters and confirmed that the permit’s limits, in light of the size of the discharge, would be sufficiently protective to address those concerns. Appx.11 at 1-2 [Standards Implementation Memo Working Papers].

Additionally, data in the Integrated Reports shows nutrient levels in Wilbarger Creek decreased from 2020 to 2022, further supporting that the limits on elements related to eutrophication contained in the Colorado River Watershed Protection Rules (which this permit complies with) are not likely to encourage an algae bloom at all, much less one that might impact Appellees. Appx.16, 17 [Integrated Report 2020, 2022 (excerpts)]; Appx.11 at 1, 2 [Standards Implementation Memo Working Papers].

Further, dissolved oxygen modeling and evaluation of the likely impact of the proposed discharge was also before the Commission; modeling that included inputs from every permitted facility that discharges into Wilbarger Creek, and assessed potential impacts on each and every section of the creek by “reaches,” which are defined segments of the creek that extend all the way to the Colorado River. Appx.13 at 1 [Water Quality Modeling Memo]; Appx.14 at 5-6, 10-11 [Water Quality Modeling Memo Working Papers]. This analysis indicated that the proposed permit effluent limits would ensure that *33 in-stream dissolved oxygen levels in Wilbarger Creek would remain suitable for high aquatic life.

The Commission had significant evidence before it that contravened Appellees’ allegations that they were likely to be injured by this permit with regard to algae and low dissolved oxygen. In addition, the Executive Director offered her opinion that Appellees were not likely to be impacted by the permit because of the distance between them and the outfall. The ED and OPIC both explained that Appellees’ allegations were not particularized or individual in nature, but, rather, were shared in common with the general public, and that therefore, Appellees had not established themselves to be affected persons under the regulatory and statutory criteria. Appx.7 at 6-8 [ED’s Resp to Hrg Req]; see also id. at 14 [map showing relative locations]; see also RR.AR.24 at 6-9 [OPIC’s Response to Req for Hrg]. The Commission considered all of Appellees’ support for their hearing requests, and the other materials allowed by statute, and reasonably and properly determined that Appellees were not likely to be injured, and reasonably rejected Appellees’ request for a contested case hearing.

D. Appellees’ distance from the plant and the nature of their allegations further support that they are not likely to be impacted in a manner different from the general public

Finally, there is the factor of Appellees’ distance from the permit’s outfall point. Ms. Kelinske’s and Ms. Brockenbrough’s addresses relative to the plant are 2.89 and 3.21 miles respectively. Appx.7 at 14 [ED’s Resp to Hrg Req]. Mr. Beall provided an Austin address, but also stated he owned land approximately “5 miles downstream” of the plant (Appx.8 at 9) “adjacent to Ms. Brockenbrough” (RR.AR.27 at 1). The Commission had this information before it when it determined whether Appellees were likely to be impacted by the plant. Appx.7 at 14 [ED’s Resp to Hrg Req].

As Chairman Niermann explained, “there is no ‘bright line’ test” because each discharge (and each watercourse) is unique, so the Commission weighs the evidence of the different factors at issue in each case to determine whether the specific requestor is likely to be affected by the specific permit at issue. Appx.4 at 191 [Open Meeting Transcript]; see also Tex. Water Code § 5.115. “[P]roximity is a factor,” and “none of the requestors own property within two and a half miles of the discharge point.” Appx.4 at 191. Appellees are a significant distance downstream as the crow flies—considerably further as the creek meanders (a.k.a. “stream miles”). Appx.7 at 14 [ED’s Resp to Hrg Req].

Distance is a factor in evaluating impacts. The Commission implements Texas’s water quality standards by reference to the EPA-Approved Standards Implementation Procedures, or IPs: 243 pages of instructions, tables, values, schematics, and formulas that provide detailed information and instructions for how to evaluate environmental impacts for compliance with water quality standards and the Commission’s water quality rules. 30 Tex. Admin. Code § 307.2(e). The IPs make clear that distance is not only a factor, it is a factor that interacts with other factors, such as whether the water is still or moving, and that those are relevant to assessing impacts downstream of a given discharge. Appx.12 at 17, 47-51, 111-112 [Implementation Procedures]. This is further demonstrated by the IPs use of *36 “stream miles” for calculation of distances when evaluating possible impacts. Id. at 47.

In addition, the Commission had before it the ED’s independent analysis of the likelihood of Appellees being affected by the permitted discharge and her opinion that their distance from the proposed outfall made that unlikely. Appx.7 at 6-8 [ED’s Resp to Hrg Req]. It also had the Office of Public Interest Counsel’s assessment that the intervening distance between the outfall and Appellees “diminishes any likelihood that the regulated activity will impact [their] health, safety, or use of property.” RR.AR.24 at 6-7 [OPIC’s Response to Requests for Hearing].

Moreover, none of Appellees’ contentions establish personal justiciable interests with a causal nexus to this permit. Appellees’ dissatisfaction with how the Commission does the job the Legislature has charged it to do and questions about the reliability of the agency’s data are not a “personal justiciable interest” distinct from the general public, nor do they pertain to this specific permit, and so fail to establish affectedness. Tex. Water Code § 5.115(a). Similarly, Appellees’ statements that they do not swim in the creek or allow their livestock to drink from it because they fear contamination, in addition to being subjective, are free-floating, and not tied to this permit, which hadn’t even been issued when they made those statements. See Tex. *37 Water Code § 5.115. They also fail the redressability test; since they reveal that the denial of this permit would not redress these injuries. See City of Waco, 346 S.W.3d at 802. Appellees’ allegations fail to establish affectedness. Tex. Water Code §§ 5.115(a), (a-1), (b). The Commission properly denied Appellees’ request for a hearing because Appellees failed to establish a “personal justiciable interest” likely to be harmed by this permit and thus didn’t merit a “trial-like proceeding with attendant expense and delay.” City of Waco, 413 S.W.3d 409, 415; see also Tex. Water Code §§ 5.556(c), 5.115.

CONCLUSION AND PRAYER

The Commission thoughtfully and carefully considered the materials before it, both those provided by Appellees and those provided by the Executive Director, Staff and others. Its decision to deny the hearing requests was reasonable and supported by those materials. For these reasons, the Court should reverse the district court order and render judgment affirming the Commission’s Final Order denying Appellees’ request for a contested case hearing and granting the permit.

Respectfully submitted,

KEN PAXTON Attorney General of Texas

BRENT WEBSTER First Assistant Attorney General

RALPH MOLINA Deputy First Assistant Attorney General

AUSTIN KINGHORN Deputy Attorney General for Civil Litigation

KELLIE E. BILLINGS-RAY Chief, Environmental Protection Division

/s/ Amanda Atkinson Cagle AMANDA ATKINSON CAGLE Assistant Attorney General Texas State Bar No. 00783569 Amanda.Cagle@oag.texas.gov

SARA J. FERRIS Assistant Attorney General Texas State Bar No. 50511915 Sara.Ferris@oag.texas.gov

OFFICE OF THE ATTORNEY GENERAL ENVIRONMENTAL PROTECTION DIVISION P.O. Box 12548, MC-066 Austin, Texas 78711-2548 Tel. 512-475-4002 Fax: 512-320-0911

ATTORNEYS FOR THE TEXAS COMMISSION ON ENVIRONMENTAL QUALITY

CERTIFICATE OF SERVICE

I certify that a true and correct copy of the foregoing Brief of Appellant TCEQ was served upon the following counsel of record on October 3, 2025 via electronic service:

Christopher D. Smith Becky L. Jolin SMITH JOLIN PLLC 901 S. Mopac Expressway Building 1, Suite 300 Austin, Texas 78746 chris.smith@smithjolin.com becky.jolin@smithjolin.com

Attorneys for Appellees

/s/ Amanda Atkinson Cagle AMANDA ATKINSON CAGLE

CERTIFICATE OF COMPLIANCE

I certify that the foregoing Brief of Appellant TCEQ contains 7,451 words and therefore complies with the word limit found in Tex. R. App. P. 9.4(i)(2)(B).

/s/ Amanda Atkinson Cagle AMANDA ATKINSON CAGLE Assistant Attorney General

INDEX OF APPENDIX ITEMS (attached)

Item No. Description 1 District Court Final Order 2 Commission’s Final Order, RR.AR.31 3 TPDES Permit No. WQ0016022001, RR.AR.29 4 Commission’s Open Meeting (RR.AR.35) Transcript, CR 190- 193 5 Executive Director’s Technical Summary and Preliminary Decision, RR.AR.12 6 Executive Director’s Response to Public Comments, RR.AR.20 7 Executive Director’s Response to Hearing Requests (color copy), RR.AR.38 8 Requestors’ Comments and Hearing Requests, RR.AR.34 9 Requestors’ Photos, RR.AR.46 10 Standards Implementation Memo, RR.AR.7 11 Standards Implementation Memo Working Papers, RR.AR.37 12 Implementation Procedures, Procedures to Implement the Texas Surface Water Quality Standards, RR.AR.39 13 Water Quality Modeling Memo, RR.AR.9 14 Water Quality Modeling Memo Working Papers, RR.AR.36 15 TCEQ’s Surface Water Quality Monitoring System Map (excerpts), RR.AR.44 16 Integrated Report 2020 (excerpts), RR.AR.42 17 Integrated Report 2022 (excerpts), RR.AR.43 18 Texas Surface Water Quality Standards: Site Specific Uses and Criteria (excerpts), 30 Tex. Admin. Code § 301.10, Appendices A-D, CR 182-188

Appendix Item 1

04/07/2025 09:36:50 AM Velva L. Price District Clerk Travis County D-1-GN-23-004031

April 4, 2025 Appendix Item 2 Appendix Item 3 Appendix Item 4

Commissioners Agenda April 26, 2023 Item No. 1 Docket No. 2023-0370-0370-MWD

Mary Smith:

Item No. 1 is the application by SWWC Utilities Incorporated for new TPDES permit number WQ 0016022001. The parties have been notified the Commission will not take oral argument but may ask questions and those who have signed in will be noted for the record.

Chairman Niermann:

So, colleagues the first five items on our docket this morning are hearing requests on TPDES permits so the same rules and analysis will pertain to our effectiveness determinations.

Chapter 55 of our rules, as you know, provides a two part analysis, first we consider whether the requestors have met both the procedural and substantive requirements to be entitled to a contested case and assuming that at least one requestor has done so we then consider which issues are appropriate to refer for hearing. So part one is about who gets a hearing and part two is about which issues are referred. Requestors who are affected in a manner different from the general public and who make timely comments articulating personal concerns that are relevant and material to the application and who express those concerns in a timely hearing request are entitled to a hearing. Associations can have standing if among other factors, they identify a member who would have standing in their own right. And on this first item, item one, colleagues, we have four requests, this is on the application by SWWC Utilities. Three of those requests are by individuals and one from an association. All three of the individuals are identified as members of the association. On this one I agree with the recommendation of the Executive Director and the Office of Public Interest Counsel that none of the requests have adequately demonstrated effectiveness. At 800,000 gallons per day, this is a relatively moderate discharge rate and none of the requestors own property within two and a half miles of the discharge point, and I do want

to emphasize that proximity is a factor, you know we know it to be an important factor, but it is not dispositive. Cases with different facts could indicate effectiveness even at distances greater than three miles. For example, the City of Liberty Hill application sought authorization for four million gallons per day of discharge, that’s five times what SWWC proposes. That case also featured evidence of actual impacts and a history of significant non-compliance, so with that different set of facts we reached a different result and the point that I’m trying to make is that what we’re doing here is we’re weighing different factors, that there is no bright line test, including none pertaining to distance. So, with that explanation out of the way, that’s how I view this particular item. Commissioner Lindley, what are your thoughts ?

Commissioner Lindley:

I’m in agreement, all I would add is I believe for some of those in the Liberty Hill case that you brought up, uh for some of the ones that I don’t remember if it was a further distance or why exactly off the top of my head, but we referred them for effectiveness, we didn’t even, you know, flat out give them party status, so uh, for the reasons you stated, I’m in agreement on denying those hearing requests.

Chairman Niermann: Commissioner Janecka ? Commissioner Janecka: Well said, I’m also in agreement and nothing different to add. Chairman Niermann: I think we are ready for a motion. Commissioner Lindley: Um, did you cover the association as well or just individuals ? *3 Chairman Niermann:

Yeah the association bases its effectiveness demonstration on the individuals and without those individuals…

Commissioner Lindley:

Yeah, and I should have clarified, I’m in, I’ll make a motion, it’s going to be deny all the hearing requests, so that will cover all of them. So, with that, I would move that we deny all hearing requests, issue new Texas Pollutant Discharge Elimination System permit number WQ0016022001 to SWWC Utilities Incorporated as recommended by the Executive Director and adopt the Executive Director’s response to comments.

Commissioner Janecka: I second the motion. Chairman Niermann: The motion has been made and seconded, all those if favor say aye. All: Aye

Chairman Niermann: Motion carries.

Appendix Item 5 Appendix Item 6

TCEQ PERMIT NO. WQ0016022001 APPLICATION BY SWWC UTILITIES, § BEFORE THE INC. FOR § TEXAS COMMISSION ON TPDES PERMIT NO. WQ0016022001 § ENVIRONMENTAL QUALITY

EXECUTIVE DIRECTOR’S RESPONSE TO PUBLIC COMMENT

The Executive Director (ED) of the Texas Commission on Environmental Quality (the commission or TCEQ) files this Response to Public Comment (RTC) on the application by SWWC Utilities, Inc., for a new Texas Pollutant Discharge Elimination System (TPDES) Permit No. WQ0016022001 and the ED’s preliminary decision. As required by Title 30 Texas Administrative Code (30 TAC) Section (§) 55.156, before a permit is issued, the ED prepares a response to all timely, relevant and material, or significant comments. The Office of Chief Clerk received timely comment from Jonathan Beall, representing Wilbarger Creek Conservation Alliance (WCCA), Marilyn Kelinske, and Anne Brockenbrough. This response addresses all timely public comments received, whether or not withdrawn. If you need more information about this permit application or the wastewater permitting process, please call the TCEQ Public Education Program at 1-800-687-4040. General information about the TCEQ can be found at our website at www.tceq.texas.gov.

I. BACKGROUND A. Description of Facility SWWC Utilities, Inc., submitted an application to the Texas Commission on Environmental Quality (TCEQ) for a new Texas Pollutant Discharge Elimination System (TPDES) Permit No. WQ0016022001 to authorize the discharge of treated domestic wastewater at a daily average flow not to exceed 200,000 gallons per day (gpd) in the Interim I phase, a daily average flow not to exceed 500,000 gpd in the Interim II phase, and a daily average flow not to exceed 800,000 gpd in the Final phase. The Majestic Manor Wastewater Treatment Plant (WWTP) will be an activated sludge process plant operated in the complete mix mode. Treatment units in all phases will include a bar screen, one aeration basin, one final clarifier, one sludge digester/sludge holding tank, an effluent filter, and one chlorine contact chamber. Treatment units in the Interim II and Final phases will increase in size and capacity. The facility has not been constructed. Sludge generated from the treatment facility will be hauled by a registered transporter to Walnut Creek Wastewater Treatment Facility, Permit No. WQ0010543011, to be digested, dewatered, and then disposed of with the bulk of the sludge from the plant accepting the sludge. The draft permit also authorizes the disposal of sludge at a TCEQ-authorized land application site, co-disposal landfill, wastewater treatment facility, or facility that further processes sludge. The plant site will be located approximately 0.42 miles southwest of the intersection of Bella Parkway and Old Texas Highway 20, in Travis County, Texas 78653. Outfall Location

Outfall Number Latitude Longitude 001 30.333492 N 97.538169 W

The treated effluent will be discharged via pipe to Wilbarger Creek, thence to Colorado River Above La Grange in Segment No. 1434 of the Colorado River Basin. The unclassified receiving water use is high aquatic life use for Wilbarger Creek. The designated uses for Segment No. 1434 are primary contact recreation, public water supply, and exceptional aquatic life use. The effluent limitations in the draft permit will maintain and protect the existing instream uses. All determinations are preliminary and subject to additional review and/or revisions. The draft permit includes the following proposed effluent limitations and monitoring requirements. All flows, except the two-hour peak flow are expressed in million gallons per day (MGD). The two-hour (2-hr) peak flow is expressed in gallons per minute (gpm). All pH values are expressed in standard units (SU). Concentration values are expressed in milligrams per liter (mg/L). Mass-based values are expressed as pounds per day (lbs/day). Bacteria values are expressed in colony-forming units (cfu) or most probable number (MPN) per 100 milliliters (cfu or MPN/100 mL). Interim I Phase: during the period beginning upon the date of issuance and lasting through the completion of expansion to the 0.50 MGD facility. Outfall Pollutant Draft Permit Effluent Limitations Daily Avg 7-day Avg Daily Max Single Grab lbs/day mg/ mg/L mg/L mg/L L 001 Flow 0.20 MGD 556 gpm Report - (2-hr peak) MGD Carbonaceous Biochemical 8.3 5 10 20 30 Oxygen Demand, 5-day (CBOD5) Total Suspended Solids (TSS) 8.3 5 10 20 30 Ammonia Nitrogen (NH3-N) 3.3 2 5 10 15 Total Phosphorus (TP) 1.7 1 2 4 6 E. coli, CFU or MPN per 100 126 - - 399 mL Dissolved Oxygen (DO), min 4.0 mg/L - - - Chlorine, Total Residual 1.0 mg/L, min 4.0 mg/L, max pH, standard units (SU) 6.0, min - 9.0 -

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Interim II Phase: during the period beginning upon the completion of expansion to the 0.50 MGD facility and lasting through the completion of expansion to the 0.80 MGD facility. Draft Permit Effluent Limitations Outfall Pollutant Daily Avg 7-day Avg Daily Max Single Grab lbs/day mg/L mg/L mg/L mg/L 1,389 gpm Report 001 Flow 0.50 MGD - (2-hr peak) MGD Carbonaceous Biochemical Oxygen Demand, 5-day 21 5 10 20 30 (CBOD5) Total Suspended Solids (TSS) 21 5 10 20 30 Ammonia Nitrogen (NH3-N) 8.3 2 5 10 15 Total Phosphorus (TP) 4.2 1 2 4 6 E. coli, CFU or MPN per 100 126 - 399 - mL Dissolved Oxygen (DO), min 4.0 mg/L - - - Chlorine, Total Residual1 1.0 mg/L, min 4.0 mg/L, max pH, standard units (SU) 6.0, min - 9.0 -

Final Phase: During the period beginning upon the completion of expansion to the 0.80 MGD facility and lasting through the date of expiration. Draft Permit Effluent Limitations Outfall Pollutant Daily Avg 7-day Avg Daily Max Single Grab lbs/day mg/L mg/L mg/L mg/L 2,222 gpm Report 001 Flow 0.80 MGD - (2-hr peak) MGD Carbonaceous Biochemical Oxygen Demand, 5-day 33 5 10 20 30 (CBOD5) Total Suspended Solids (TSS) 33 5 10 20 30 Ammonia Nitrogen (NH3-N) 13 2 5 10 15 Total Phosphorus (TP) 6.7 1 2 4 6 E. coli, CFU or MPN per 100 126 - 399 - mL Dissolved Oxygen (DO), min 4.0 mg/L - - - Chlorine, Total Residual1 1.0 mg/L, min 4.0 mg/L, max pH, standard units (SU) 6.0, min - 9.0 -

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1 The permittee shall dechlorinate the chlorinated effluent to less than 0.1 mg/l

total chlorine residual and shall monitor total chlorine residual daily by grab sample after the dechlorination process. B. Procedural Background The permit application was received on July 28, 2021 and declared administratively complete on November 17, 2021. The Notice of Receipt and Intent to Obtain a Water Quality Permit (NORI) was published in English on December 16, 2021, in the Austin American Statesman newspaper. The Notice of Application and Preliminary Decision (NAPD) was published in English on June 30, 2022, in the Austin American Statesman newspaper. The public comment period ended on August 1, 2022. This application was filed on or after February 12, 2019; therefore, this application is subject to the procedural requirements adopted pursuant to House Bill (HB) 801, 76th Legislature (1999), and Senate Bill (SB) 709, 84th Legislature (2015), both implemented by the Commission in its rules in 30 TAC Chapter 39, 50, and 55. The Texas Legislature enacted Senate Bill 709, effective September 1, 2015, amending the requirements for comments and contested case hearings. This application is subject to those changes in the law. C. Access to Rules, Laws and Records Please consult the following websites to access the rules and regulations applicable to this permit: • the Secretary of State website: https://www.sos.state.tx.us; • TCEQ rules in Title 30 of the Texas Administrative Code (TAC): www.sos.state.tx.us/tac/ (select “View the current Texas Administrative Code” on the right, then “Title 30 Environmental Quality”); • Texas statutes: www.statutes.capitol.texas.gov/; • the TCEQ website: www.tceq.texas.gov (for downloadable rules in Adobe PDF format, select “Rules” then “Current Rules and Regulations,” then “Download TCEQ Rules”); • Federal rules in Title 40 of the Code of Federal Regulations: www.ecfr.gov; and • Federal environmental laws: http://www2.epa.gov/laws-regulations. Federal environmental laws and executive orders: www2.epa.gov/laws-regulations/laws- and-executive-orders. Commission records for this application and draft permit are available for viewing and copying at the TCEQ’s main office in Austin, 12100 Park 35 Circle, Building F, 1st Floor (Office of the Chief Clerk), until final action is taken. The permit application for this facility, Statement of Basis/Technical Summary and Executive Director’s Preliminary Decision (Statement of Basis), and proposed draft permit are available for viewing and copying at Manor City Hall, 105 East Eggleston Street, Manor, Texas. D. Acronyms

CBOD5- 5-day Carbonaceous Biochemical Oxygen Demand DO- Dissolved Oxygen ED- Executive Director EPA- Environmental Protection Agency GPM- Gallons per Minute

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HB- House Bill IPs- Procedures to Implement the Texas Surface Water Quality Standards MGD- Million Gallons per Day mg/L- Milligrams per Liter NAPD- Notice of Application and Preliminary Decision NH3-N- Ammonia-Nitrogen NORI- Notice of Receipt of Application and Intent to Obtain a Water Quality Permit NPDES- National Pollutant Discharge Elimination System pH- Potential Hydrogen RTC- Response to Comments SU- Standard Units SWQM- Surface Water Quality Monitoring TAC- Texas Administrative Code TCEQ- Texas Commission on Environmental Quality TLAP- Texas Land Application Permit TP- Total Phosphorus TSS- Total Suspended Solids TMDL- Total Maximum Daily Load TNR- Transportation and Natural Resources TPDES- Texas Pollutant Discharge Elimination System TPWD- Texas Parks and Wildlife Department TSWQS- Texas Surface Water Quality Standards TWC- Texas Water Code WWTF- Wastewater Treatment Facility WWTP- Wastewater Treatment Plant

II. COMMENTS AND RESPONSES COMMENT 1: Ms. Kelinske commented that Wilbarger Creek and its tributaries run across her property and in recent years the creek has become cloudy many times and clogged with algae. Fish and frogs that earlier were abundant are no longer found. Ms. Brockenbrough is concerned that adding more wastewater to the creek will impair the water quality even more. Mr. Beall asked how the discharge will affect the health of Wilbarger Creek and asked that TCEQ determine the cause of the existing algae bloom before adding more treated effluent. RESPONSE 1: The draft permit was developed to protect aquatic life and human health in accordance with the TSWQS 30 TAC Chapter 307 and was established to be protective of human health and the environment, provided that the applicant operates and maintains the facility according to TCEQ rules and the requirements in the draft permit. As part of

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the permit application process, TCEQ must determine the uses of the receiving water and set effluent limits that are protective of those uses. The effluent limits in the draft permit are set to maintain and protect the existing instream uses. Wilbarger Creek has been assigned a High Aquatic Life Use and corresponding 5.0 mg/L DO criterion in the TSWQS. These criteria are designed to ensure that aquatic life will be protected. The proposed discharge for the Majestic Manor WWTF is to the perennial portion of Wilbarger Creek, which has high aquatic life use designation. To address potential algal blooms, a nutrient screening was conducted for this permit application, and it was determined that nutrient limits were needed. A TP limit of 1.0 mg/L was recommended for all discharge flow phases and incorporated into the draft permit. This TP limit meets the requirement for the Colorado River Watershed Protection Rule, 30 TAC Chapter 311, Subchapter E and should prevent any further or potential degradation from the proposed discharge. In addition, the draft permit includes a 2.0 mg/L ammonia-nitrogen limit for all discharge flow phases. In accordance with 30 TAC §307.5 and the TCEQ IPs (June 2010), an antidegradation review of the receiving waters was performed. A Tier 1 antidegradation review has preliminarily determined that existing water quality uses will not be impaired by this permit action. Numerical and narrative criteria to protect existing uses will be maintained. A Tier 2 review has preliminarily determined that no significant degradation of water quality is expected in Wilbarger Creek and Colorado River Above La Grange, which have been identified as having high and exceptional aquatic life uses, respectively. Existing uses will be maintained and protected. The preliminary determination can be reexamined and may be modified if new information is received. TCEQ staff performed a DO modeling analysis of the proposed discharge using an uncalibrated QUAL-TX model. Based on model results, the effluent limits included in the draft permit for CBOD5, NH3-N, and minimum DO for the three proposed flow phases are predicted to be adequate to ensure that instream DO levels will be maintained consistent with these established criteria. As mentioned above, the effluent limits in the draft permit also comply with the requirements of 30 TAC Chapter 311, Subchapter E that requires effluent limits of 5 mg/L TSS, which helps protect water clarity, and 1.0 mg/L TP to protect against excessive algal growth. COMMENT 2: Ms. Brockenbrough is concerned that adding more wastewater into the creek will cause increased flooding and erosion on her property. Ms. Brockenbrough states that over the past 25 years the creek has changed from being a seasonal intermittent stream to a continuously flowing stream, often with a high flow, due to added effluent from Manor and Shadow Glen wastewater treatment plants both located upstream of her property. The increased flooding has caused fences to blow out and livestock to escape. Ms. Kelinske is concerned about the increased flooding caused by Wilbarger Creek that occurs with modest rains. She also is concerned about its effect on vegetation and animals. RESPONSE 2: TPDES permits establish terms and conditions that are intended to provide water quality pollution control. Therefore, the ED’s review of an application for a TPDES permit focuses on controlling the discharge of pollutants into water in the state. TCEQ does not have the authority to regulate flooding in the wastewater permitting process unless there is an associated water quality concern. The draft permit includes effluent limits and other requirements that it must meet even during rainfall events and periods of flooding. Finally, the draft permit does not authorize any invasion of personal rights nor any violation of federal, state, or local laws or regulations. As stated in subsection C of

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the Background Information (Access to Rules, Laws, and Records), the proposed permit does not limit any landowner’s ability to seek private action against the applicant. For flooding concerns, please contact the local floodplain administrator for Travis County (Call Travis County TNR 512-854-9383; Email TNR.Web@TravisCountyTx.gov. COMMENT 3: Ms. Kelinske expressed concern about negative impact on wildlife living on a conservation easement on her property. She stated that with the population growth around, her property has become a haven for wildlife. Ms. Kelinske further expressed concern about using the creek water for horses and livestock due to the contamination of the water. RESPONSE 3: The TSWQS in 30 TAC Chapter 307 require that discharges may not degrade the receiving waters and may not result in situations that impair existing, attainable, or designated uses, and that surface waters not be toxic to aquatic life, terrestrial wildlife, livestock, or domestic animals. As stated in Response 1, the draft permit was developed in accordance with the TSWQS to be protective of water quality, provided that the applicant operates and maintains the proposed WWTF according to TCEQ rules and the draft permit’s requirements. The methodology outlined in the IPs (June 2010) is designed to ensure compliance with the TSWQS. Specifically, the methodology is designed to ensure that no source will be allowed to discharge any wastewater that 1) results in instream aquatic toxicity, 2) causes a violation of an applicable narrative or numerical state water quality standard, 3) results in the endangerment of a drinking water supply, or 4) results in aquatic bioaccumulation that threatens human health. The ED has made a preliminary determination that the draft permit, if issued, meets all statutory and regulatory requirements. Finally, TPWD is the state agency that oversees and protects wildlife and their habitat. TPWD can be contacted by phone at 1-800-792-1112 or by mail at 4200 Smith School Road, Austin, Texas 78744. COMMENT 4: Ms. Kelinske opposes any new discharge directly into Wilbarger Creek because the creek already receives discharges from other sources such as Pflugerville and Manor subdivisions. Mr. Beall expressed concern about the capacity of Wilbarger Creek as the creek already receives treated effluent from Shadow Glen and the City of Manor. He stated that Pflugerville’s new regional WWTP, which is not online yet, is permitted to discharge 24 MGD. He expressed concern about future negative impacts of Pflugerville’s WWTP and stated that TCEQ should err on the side of caution and requested that TCEQ include this effluent discharge in considering the Majestic Manor permit as the stream flow will be predominately treated effluent. Mr. Beall stated that it seems irresponsible to permit additional discharges before the true impacts of Pflugerville’s regional plant are clearer. Downstream neighbors, taxpayers, and aquatic environment should not have to suffer so that this wastewater operator can save a little money. RESPONSE 4: Part of the technical review process is for TCEQ staff to perform a DO modeling analysis to ensure the permit’s effluent limits and other requirements will support the DO criterion and, therefore, protect the aquatic life use of the receiving waterbodies (i.e., Wilbarger Creek).

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The model for Wilbarger Creek used to assess whether the DO criteria for the stream is met, is a large model that contains multiple TPDES wastewater outfalls (including but not limited to the City of Manor [TPDES permit Nos. WQ0012900001 and WQ001412901] and City of Pflugerville [TPDES permit Nos. WQ0011845005 and WQ0014642001]). When running the model, all contributing dischargers are entered at their full permitted flow. Furthermore, to ensure that DO modeling results and corresponding effluent limit recommendations are conservative and protective under all conditions, Wilbarger Creek was evaluated under what are expected to be the most unfavorable of environmental conditions, specifically hot and dry summertime conditions. This combination of conditions is unlikely to occur for any significant period of time, so it represents a very conservative, worst-case modeling scenario. Even under these conservative model assumptions, instream DO levels were predicted to be maintained above the criterion established for Wilbarger Creek (5.0 mg/L). The City of Pflugerville currently has two TPDES permits that discharge to Wilbarger Creek (TPDES Permit Nos. WQ0011845005 and WQ0014642001). Permit No. WQ0011845005 (issued July 25, 2022) authorizes a daily average flow of 6.0 MGD for the Interim phase and 15.75 MGD for the final phase. Permit No. WQ0014642001 (issued December 6, 2019) authorizes a daily average flow of 0.15 MGD, 0.475 MGD, and 0.95 MGD for the Interim phases and 3.0 MGD for the final phase. The Wilbarger Creek Regional WWTF referenced by Mr. Beall (https://www.pflugervilletx.gov/city-government/capital-improvement-program- cip/projects-overview/wilbarger-creek-regional-wastewater-treatment-facility) does not currently hold a TPDES wastewater permit that authorizes the daily average discharge of 24 MGD. If the City does apply for such a permit, the application will undergo a full technical review by TCEQ to determine if the discharge conditions proposed in the application would be sufficient to protect the human health and aquatic life uses of the receiving waterbodies. COMMENT 5: Ms. Brockenbrough requested that TCEQ test the water in Wilbarger Creek downstream from the proposed Majestic Manor WWTF before approving the permit. She believes a TMDL study is needed. Ms. Kelinske asks if studies have been done to understand the effect on vegetation and animals when increased flooding occurs due to effluent mixed with stormwater overflow over hundreds of acres of land adjacent to the banks of the creek. Ms. Kelinske also asks how long this effect would last. Mr. Beall asks if TCEQ has a good water quality baseline of Wilbarger Creek, and if so, how old is it? Mr. Beall requests a current baseline be taken during the last year. Samples should be taken above and below the discharge points on the 5 existing and proposed WWTP on Wilbarger Creek: Pflugerville, Shadow Glen, Manor, Majestic Manor, and Elgin. RESPONSE 5: TMDL projects are conducted on water bodies that have been found to be impaired for some specific constituent(s) or other water quality-related parameter(s). Such impairments are documented in the Texas 303(d) list (Category 5) portion of the Texas Integrated Report of Surface Water Quality, which is updated every two years. Wilbarger Creek is not listed as impaired on the 303(d) list and no TMDL projects have been developed for the Wilbarger Creek watershed, nor are any currently underway or planned. The SWQM program of the TCEQ conducts an updated assessment of water quality in water bodies throughout the state (including Wilbarger Creek) every two years, comparing observed water quality from sampling data against various applicable water quality criteria. TCEQ has water quality information that is collected at an active SWQM Station approximately 2.25 miles downstream of the Majestic Manor WWTF. In addition,

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there are other active SWQM stations further upstream and downstream on Wilbarger Creek, in which current water quality data is being collected. COMMENT 6: Ms. Kelinske, Ms. Brockenbrough, and Mr. Beall request that higher treatment standards be required for facilities discharging into Wilbarger Creek. Mr. Beall asks that TCEQ consider using the highest possible treatment standards to include the most protective and available techniques:

• • A limit of total nutrients of 0.1 mg/l phosphorus and 4 mg/l nitrogen. • Discharge the treated effluent to wet ponds, wetlands, and sheet flow over a vegetated buffer to significantly improve stream inputs and to mitigate negative effects from chlorination of the discharge. • Use land application permits – or no discharge permits. • Beneficial reuse – irrigation, wetlands, or other beneficial reuse to preserve potable water resources. RESPONSE 6: TCEQ does not have the authority to mandate the method of disposal of treated effluent if an applicant adheres to the rules and provisions of TWC Chapter 26 and 30 TAC Chapters 217, 305, 307, and 309. A TLAP authorizes the disposal of treated effluent by means of surface irrigation, subsurface irrigation, or evaporation. The effluent must be treated to the pollutant concentrations prescribed in 30 TAC § 309.4. If SWWC Utilities Inc. changes the proposed method of disposal this would require further review by the TCEQ and additional public notice. Treated effluent may also be used for beneficial use pursuant to 30 TAC Chapter 210, relating to “Use of Reclaimed Water,” however this authorization requires that either a TPDES or TLAP permit be obtained first. The current draft permit contains an NH3-N of 2.0 mg/L for all proposed flow phases, which is the minimum required by the Colorado River Watershed Protection Rule (30 TAC Chapter 311, Subchapter E). COMMENT 7: Mr. Beall expressed concern about malfunctions of treatment plants due to power outages, floods, mechanical failures, etc. resulting in exceedances of permit limits, even in a well-run plant. Mr. Beall stated that it would have a severe impact on Wilbarger Creek because it is so small. Using land application, beneficial reuse etc. will provide a buffer if a plant has problems. RESPONSE 7: The draft permit prohibits unauthorized discharge of wastewater or any other waste and includes appropriate requirements. For example, a permittee must maintain adequate safeguards to prevent the discharge of untreated or inadequately treated wastes during electrical power failures by means of alternate power sources, standby generators, or retention of inadequately treated wastewater. In addition, the plans and specifications for domestic sewage collection and treatment works associated with any domestic wastewater permit must be approved by TCEQ. All these permit provisions are designed to help prevent unauthorized discharges of raw sewage. Except as allowed by 30 TAC § 305.132, the SWWC Utilities Inc. will be required to report any unauthorized discharge to TCEQ within 24 hours and the SWWC Utilities Inc. will be subject to potential enforcement action for failure to comply with TCEQ rules or the permit.

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If you would like to file a complaint about the facility concerning its compliance with provisions of its permit or with TCEQ rules, you may call the TCEQ Environmental Complaints Hot Line at 1-888-777-3186 or the TCEQ Region 11 Office at 512-339-2929. Citizen complaints may also be filed on-line at https://www.tceq.texas.gov/assets/public/compliance/monops/complaints/complaints. html. COMMENT 8: Mr. Beall stated that the actual discharge point is not clear from the notice and that it seems like an unreasonable burden to require people to obtain and read the application to find the discharge point. RESPONSE 8: The ED acknowledges the comment.

III. CHANGES MADE TO THE DRAFT PERMIT IN RESPONSE TO COMMENTS No changes were made to the draft permit in response to comments.

Respectfully submitted, Texas Commission on Environmental Quality Toby Baker Executive Director Charmaine Backens, Deputy Director Environmental Law Division

Anthony Tatu, Staff Attorney Environmental Law Division State Bar No. 00792869 P.O. Box 13087, MC 173 Austin, Texas 78711-3087 Phone: (512) 239-5778 Fax: (512) 239-0606

REPRESENTING THE EXECUTIVE DIRECTOR OF THE TEXAS COMMISSION ON ENVIRONMENTAL QUALITY

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CERTIFICATE OF SERVICE I certify that on October 19, 2022, the “Executive Director’s Response to Public Comment” for Permit No. WQ0016022001 was filed with the Texas Commission on Environmental Quality’s Office of the Chief Clerk.

Anthony Tatu, Staff Attorney Environmental Law Division State Bar No. 00792869

Appendix Item 7

Jon Niermann, Chairman Emily Lindley, Commissioner Bobby Janecka, Commissioner Erin E. Chancellor, Interim Executive Director

TEXAS COMMISSION ON ENVIRONMENTAL QUALITY Protecting Texas by Reducing and Preventing Pollution

April 3, 2023

Ms. Laurie Gharis, Chief Clerk Office of the Chief Clerk Texas Commission on Environmental Quality P.O. Box 13087, MC- 105 Austin, Texas 78711-3087

RE: Application by SWWC Utilities Inc for Permit No. WQ0016022001; TCEQ Docket No. 2023-0370-MWD

Dear Ms. Gharis:

Enclosed for filing with the Texas Commission on Environmental Quality (Commission) is the Executive Director’s Response to Hearing Requests. Please do not hesitate to contact me at Anthony.Tatu@tceq.texas.gov or (512) 239-5778 if you have any questions. Thank you for your attention to this matter.

Respectfully submitted,

Anthony Tatu, Staff Attorney Environmental Law Division

Enclosure Cc: Mailing List

AR Item 38, Page 001

P.O. Box 13087 • Austin, Texas 78711-3087 • 512-239-1000 • tceq.texas.gov How is our customer service? tceq.texas.gov/customersurvey printed on recycled paper

TCEQ DOCKET NO. 2023-0370-MWD

APPLICATION BY § BEFORE THE TEXAS SWWC UTILITIES INC. § COMMISSION FOR PERMIT NO. § ON WQ0016022001 § ENVIRONMENTAL QUALITY

EXECUTIVE DIRECTOR’S RESPONSE TO HEARING REQUESTS

I. Introduction The Executive Director of the Texas Commission on Environmental Quality (TCEQ or Commission) files this Response to Hearing Requests (Response) on the application of SWWC Utilities for new TPDES Permit No. WQ0016022001. The Office of the Chief Clerk (OCC) received 18 hearing requests filed by 3 individuals and one organization. Anne Brockenbrough, Marilyn Kelinske, and Jonathan Beall all filed individual hearing requests. In addition, they filed a hearing request on behalf of the Wilbarger Creek Conservation Alliance (WCCA). Attached for Commission consideration is a Geographic Information Systems (GIS) map of requestors in the area of the facility (Attachment A). The Draft Permit, Technical Summary, Executive Director’s Preliminary Decision, and the Executive Director’s Response to Public Comment can be found in the Agenda backup materials filed for the Commission’s consideration.

II. Description of the Facility SWWC Utilities, Inc., submitted an application to the Texas Commission on Environmental Quality (TCEQ) for a new Texas Pollutant Discharge Elimination System (TPDES) Permit No. WQ0016022001 to authorize the discharge of treated domestic wastewater at a daily average flow not to exceed 200,000 gallons per day (gpd) in the Interim I phase, a daily average flow not to exceed 500,000 gpd in the Interim II phase, and a daily average flow not to exceed 800,000 gpd in the Final phase. The treated effluent will be discharged via pipe to Wilbarger Creek, thence to Colorado River above La Grange in Segment No. 1434 of the Colorado River Basin. The unclassified receiving water use is high aquatic life use for Wilbarger Creek. The designated uses for Segment No. 1434 are primary contact recreation, public water supply, and exceptional aquatic life use. The effluent limitations in the draft permit will maintain and protect the existing instream uses. The plant site will be located approximately 0.42 miles southwest of the intersection of Bella Parkway and Old Texas Highway 20, in Travis County, Texas 78653.

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III. Procedural Background The permit application was received on July 28, 2021 and declared administratively complete on September 17, 2021. The Notice of Receipt and Intent to Obtain a Water Quality Permit (NORI) was published in English on December 16, 2021, in the Austin American Statesman newspaper. The Notice of Application and Preliminary Decision (NAPD) was published in English on June 30, 2022, in the Austin American Statesman newspaper. The public comment period ended on August 1, 2022. This application was filed on or after February 12, 2019; therefore, this application is subject to the procedural requirements adopted pursuant to House Bill (HB) 801, 76th Legislature (1999), and Senate Bill (SB) 709, 84th Legislature (2015), both implemented by the Commission in its rules in 30 TAC Chapter 39, 50, and 55. The Texas Legislature enacted Senate Bill 709, effective September 1, 2015, amending the requirements for comments and contested case hearings. This application is subject to those changes in the law.

IV. Evaluation of Hearing Requests House Bill 801 established statutory procedures for public participation in certain environmental permitting proceedings, specifically regarding public notice and public comment and the Commission’s consideration of hearing requests. The Commission implemented HB 801 by adopting procedural rules in Title 30 of the Texas Administrative Code (30 TAC) chapters 39, 50, and 55. Senate Bill 709 revised the requirements for submitting public comment and the Commission’s consideration of hearing requests. This application was declared administratively complete on September 17, 2021; therefore, it is subject to the procedural requirements adopted pursuant to HB 801 and SB 709.

A. Legal Authority to Respond to Hearing Requests “The Executive Director, the public interest counsel, and applicant may submit written responses to [hearing] requests . . . .” 1 Responses to hearing requests must specifically address: (a) whether the requestor is an affected person; (b) whether issues raised in the hearing request are disputed; (c) whether the dispute involves questions of fact or law; (d) whether the issues were raised during the public comment period; (e) whether the hearing request is based on issues raised solely in a public comment withdrawn by the commenter in writing by filing a withdrawal

AR Item 38, Page 003 1 30 TAC §55.209(d). Executive Director’s Response to Hearing Requests Page 2 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

letter with the chief clerk prior to the filing of the Executive Director’s Response to Comment; (f) whether the issues are relevant and material to the decision on the application; and (g) a maximum expected duration for the contested case hearing. 2

B. Hearing Request Requirements In order for the Commission to consider a hearing request, the Commission must first determine whether the request meets certain requirements. A request for a contested case hearing by an affected person must be in writing, filed with the chief clerk within the time provided . . ., based only on the requestor’s timely comments, and not based on an issue that was raised solely in a public comment withdrawn by the commenter in writing by filing a withdrawal letter with the chief clerk prior to the filing of the Executive Director’s Response to Comment. 3 A hearing request must substantially comply with the following: (1) give the name, address, daytime telephone number, and where possible, fax number of the person who files the request. If the request is made by a group or association, the request must identify one person by name, address, daytime telephone number, and where possible, fax number, who shall be responsible for receiving all official communications and documents for the group; (2) identify the person’s justiciable interest affected by the application, including a brief, but specific, written statement explaining in plain language the requestor’s location and distance relative to the proposed facility or activity that is the subject of the application and how and why the requestor believes he or she will be adversely affected by the proposed facility or activity in a manner not common to members of the general public; (3) request a contested case hearing; (4) list all relevant and material disputed issues of fact that were raised during the public comment period by the requestor and that are the basis of the hearing request. To facilitate the commission’s determination of the number and scope of issues to be referred to hearing, the requestor should, to the extent possible, specify any of the executive director’s responses to comments that the requestor disputes and the factual basis of the dispute and list any disputed issues of law; and (5) provide any other information specified in the public notice of application. 4

2 30 TAC §55.209(e). 3 30 TAC §55.201(c). AR Item 38, Page 004 4 30 TAC §55.201(d). Executive Director’s Response to Hearing Requests Page 3 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

C. Requirement that Requestor be an Affected Person In order to grant a contested case hearing, the commission must determine that a requestor is an affected person. (a) For any application, an affected person is one who has a personal justiciable interest related to a legal right, duty, privilege, power, or economic interest affected by the application. An interest common to members of the general public does not qualify as a personal justiciable interest. (b) Governmental entities, including local governments and public agencies with authority under state law over issues raised by the application may be considered affected persons. (c) In determining whether a person is an affected person, all factors shall be considered, including, but not limited to, the following: (1) whether the interest claimed is one protected by the law under which the application will be considered; (2) distance restrictions or other limitations imposed by law on the affected interest; (3) whether a reasonable relationship exists between the interest claimed and the activity regulated; (4) likely impact of the regulated activity on the health and safety of the person, and on the use of property of the person; (5) likely impact of the regulated activity on use of the impacted natural resource by the person; and (6) whether the requestor timely submitted comments on the application which were not withdrawn; and (7) for governmental entities, their statutory authority over or interest in the issues relevant to the application. 5 (d) In making this determination, the commission may also consider, to the extent consistent with case law: (1) the merits of the underlying application and supporting documentation in the commission’s administrative record, including whether the application meets the requirements for permit issuance; (2) the analysis and opinions of the executive director; and (3) any other expert reports, affidavits, opinions, or data submitted by the executive director, the applicant, or hearing requestor. 6

5 30 TAC § 55.203. AR Item 38, Page 005 6 30 TAC § 55.203. Executive Director’s Response to Hearing Requests Page 4 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

D. Referral to the State Office of Administrative Hearings “When the commission grants a request for a contested case hearing, the commission shall issue an order specifying the number and scope of the issues to be referred to SOAH for a hearing.” 7 “The commission may not refer an issue to SOAH for a contested case hearing unless the commission determines that the issue: (1) involves a disputed question of fact or a mixed question of law and fact; (2) was raised during the public comment period by an affected person; and (3) is relevant and material to the decision on the application.” 8

V. Analysis of the Requests The Executive Director has analyzed the hearing requests to determine whether they comply with Commission rules, who qualifies as an affected person, what issues may be referred for a contested case hearing, and what is the appropriate length of the hearing. A. Whether the Individual Requestors Complied with 30 TAC §§ 55.201(c) and (d). The Executive Director reviewed the factors found in 30 TAC §§ 55.201(c) and (d), and 55.205 for determining if an individual or group meets the requirements for a contested case hearing and recommends the Commission find that Marilyn Kelinske, Anne Brockenbrough, Jonathan Beall and WCCA are not affected persons.

1. Marilyn Kelinske The Executive Director reviewed the factors found in 30 TAC §§ 55.201(c) and (d), and 55.203 for determining if a person is an affected person and recommends the Commission find that Marilyn Kelinske is not an affected person. Ms. Kelinske submitted timely hearing requests in writing, provided the required contact information, and raised issues that are the basis of her hearing requests in her timely comments. Ms. Kelinske states that she owns property on 11561 Littig Road. According to the GIS map prepared by the TCEQ this property is approximately 2.8 miles downstream from the proposed outfall. Ms. Kelinske’s concerns are common to the general public, and she failed to prove that she has a personal justiciable interest related to a legal right, duty, privilege, power, or economic interest affected by the application not common to members of the general public and is not an affected person. Based on the available information, the Executive Director recommends finding that Ms. Kelinske is not an affected person. Ms. Kelinske raised Issues 1, 2, 3, and 4, in her requests.

7 30 TAC § 50.115(b). AR Item 38, Page 006 8 30 TAC § 50.115(c). Executive Director’s Response to Hearing Requests Page 5 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

2. Anne Brockenbrough The Executive Director reviewed the factors found in 30 TAC §§ 55.201(c) and (d), and 55.203 for determining if a person is an affected person and recommends the Commission find that Anne Brockenbrough is not an affected person. Ms. Brockenbrough submitted timely hearing requests in writing, provided the required contact information, and raised issues that are the basis of her hearing requests in her timely comments. Ms. Brockenbrough states that she owns and lives on a working ranch three miles downstream from the proposed facility, which is reflected in the attached GIS map. Ms. Brockenbrough’s concerns are common to the general public, and she failed to prove that she has a personal justiciable interest related to a legal right, duty, privilege, power, or economic interest affected by the application not common to members of the general public. Based on the available information, the Executive Director cannot recommend finding that Ms. Brockenbrough is an affected person.

3. Jonathan Beall The Executive Director reviewed the factors found in 30 TAC §§ 55.201(c) and (d), and 55.203 for determining if a person is an affected person and recommends the Commission find that Jonathan Beall is not an affected person. Mr. Beall submitted timely hearing requests in writing, provided the required contact information, and raised issues that are the basis of his hearing requests in timely comments. Mr. Beall states that he owns property 5 miles downstream from the proposed facility but does not provide an address for this property. Mr. Beall’s mailing address is reflected on the attached GIS map. Mr. Beall’s concerns are common to the general public, and he failed to prove that he has a personal justiciable interest related to a legal right, duty, privilege, power, or economic interest affected by the application not common to members of the general public. Based on the available information, the Executive Director cannot recommend finding that Mr. Beall is an affected person.

4. Wilbarger Creek Conservation Alliance (WCCA) The Executive Director reviewed the factors found in 30 TAC §§ 55.201(c) and (d), and 55.205 for determining if a group or organization is an affected person and recommends the Commission find that WCCA is not an affected person. In addition to the requirements in 30 TAC § 55.201 and 30 TAC § 55.203, a request for a contested case hearing by a group or association on an application filed on or after September 1, 2015 must meet the requirements in 30 TAC § 55.205(b). 30 TAC § 55.205(b) requires that the organization identify one or more members of the group or association would otherwise have standing to request a hearing in their own right. In their hearing request, WCCA failed to identify any member of the organization who had a justiciable interest that could be affected by this application. AR Item 38, Page 007

Executive Director’s Response to Hearing Requests Page 6 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

WCCA submitted a timely hearing request in writing, provided the required contact information, and raised the issues that are the basis of their hearing request in their timely comments. According to the hearing request, the mission of the WCCA is to preserve and protect the water quality of Wilbarger Creek. WCCA identified Marilyn Kelinske, Anne Brockenbrough, and Jonathan Beall as members who own property downstream from the proposed site. The hearing request states their properties are almost 5 miles downstream, but the proposed discharge will affect all of them. The hearing request also raises the issue of cumulative impacts to Wilbarger Creek. Therefore, as WCCA failed to identify any members of the association who would otherwise have standing to request a hearing in their own right, the Executive Director has determined that WCCA has not met this this requirement for associational standing and should not be considered an affected person. WCCA raised Issues 1, 2, 3, and 4, in its requests. B. Whether the Issues Raised May be Referred to SOAH for a Contested Case Hearing. The Executive Director has identified issues of disputed questions of fact or mixed questions of law and fact, raised during the comment period, in requests for a contested case hearing, and relevant to the decision on the application that could be referred to SOAH if the commission determines that a requestor is an affected person. The issues discussed were raised during the public comment period and addressed in the RTC. None of the issues were withdrawn. All identified issues in this response are considered disputed, unless otherwise noted.

A. Referable Issues to SOAH for a Contested Case Hearing

Issue 1: Whether the draft is protective of aquatic life and terrestrial wildlife in and adjacent to Wilbarger Creek. (RTC no. 1 and no. 3) The issue involves a disputed question of mixed fact and law, was raised during the comment period, was not withdrawn, and is relevant and material to the issuance of the draft permit. The Executive Director recommends the Commission refer this issue to SOAH. Issue 2: Whether the draft permit should require higher treatment standards to include the most protective and available techniques. (RTC no. 6) The issue involves a disputed question of fact, was raised during the comment period, was not withdrawn, and is relevant and material to the issuance of the draft permit. The Executive Director recommends the Commission refer this issue to SOAH. Issue 3: Whether the cumulative impacts of the proposed discharge into Wilbarger Creek were properly modeled and evaluated. (RTC No. 4) The issue involves a disputed question of mixed fact and law, was raised during the comment period, was not withdrawn, and is relevant and material to the issuance of the draft permit. The Executive Director recommends the Commission refer this issue to SOAH.

AR Item 38, Page 008

Executive Director’s Response to Hearing Requests Page 7 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

Issue 4: Whether the permit application addresses potential malfunctions at the proposed facility. (RTC no. 7) The issue involves a disputed question of fact, was raised during the comment period, was not withdrawn, and is relevant and material to the issuance of the draft permit. The Executive Director recommends the Commission refer this issue to SOAH.

B. Issues that are not relevant or Material to the Commission’s Consideration or that are Matters of Law or Policy.

Issue 1: Whether the proposed discharge will result in increased flooding and erosion in Wilbarger Creek. (RTC No. 2) The issue involves a disputed question of fact, was raised during the comment period and was not withdrawn. However, it is not relevant and material to the issuance of the draft permit as it is not something TCEQ reviews as part of the application process. Therefore, the Executive Director does not recommend the Commission refer this issue to SOAH.

VI. Contested Case Hearing Duration If there is a contested case hearing on this application, the Executive Director recommends that the duration of the hearing be six months from the preliminary hearing to the presentation of a proposal for decision to the Commission.

VII. Executive Director’s Recommendation The Executive Director recommends the following actions by the Commission: 1. The Executive Director recommends the Commission deny the Requests for Hearing filed by Marilyn Kelinske, Anne Brockenbrough, Jonathan Beall and the Wilbarger Creek Conservation Alliance. 2. If referred to SOAH, that the duration of the hearing be six months from the preliminary hearing to the presentation of the proposal for decision to the Commission. 3. If referred to SOAH, concurrently refer the matter to Alternative Dispute Resolution. 4. If referred to SOAH, refer the issues 1-4 listed above in part V of this response.

AR Item 38, Page 009

Executive Director’s Response to Hearing Requests Page 8 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

Respectfully submitted,

Texas Commission on Environmental Quality

Erin Chancellor Interim Executive Director

Guy Henry, Acting Deputy Director Environmental Law Division

.·.· .•.· .· - . a;: Anthony Tatu , Staff Attorney Environmental Law Division State Bar No. 00792869 P.O. Box 13087, MC 173 Austin, Texas 78711-3087 Phone (512) 239-5778 REPRESENTING THE EXECUTIVE DIRECTOR OF THE TEXAS COMMISSION ON ENVIRONMENTAL QUALITY

AR Item 38, Page 010

Executive Director’s Response to Hearing Requests Page 9 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

VIII. CERTIFICATE OF SERVICE I certify that on, April 3, 2023, the “Executive Director’s Response to Hearing Requests” on the application by SWWC Utilities TPDES Permit No. WQ0002659000 was filed with the TCEQ’s Office of the Chief Clerk, and a complete copy was served to all persons listed on the attached mailing list via hand delivery, facsimile transmission, inter-agency mail, electronic submittal, or by deposit in the U.S. Mail.

Anthony Tatu, Staff Attorney Environmental Law Division State Bar No. 00792869 P.O. Box 13087, MC 173 Austin, Texas 78711-3087 Phone (512) 239-5778 Fax: (512) 239-0626

AR Item 38, Page 011

Executive Director’s Response to Hearing Requests Page 10 SWWC Utilities Inc. TPDES Permit No. WQ0016022001 TCEQ Docket No. 2023-0370-MWD

MAILING LIST SWWC Utilities, Inc. TCEQ Docket No. 2023-0370-MWD; TPDES Permit No. WQ0016022001

FOR THE APPLICANT FOR ALTERNATIVE DISPUTE RESOLUTION via electronic mail: Jeffrey McIntyre, President Texas Utilities Kyle Lucas SWWC Utilities, Inc. Texas Commission on Environmental 12535 Reed Road Quality Sugar Land, Texas 77478 Alternative Dispute Resolution, MC-222 P.O. Box 13087 Joe Torralva, Design and Construction Austin, Texas 78711 Manager, Texas Utilities Kyle.lucas@tceq.texas.gov SWWC Utilities, Inc. 1620 Grand Avenue Parkway, Suite 140 FOR THE CHIEF CLERK Pflugerville, Texas 78660 via eFilings: Docket Clerk Jason Baze, P.E., Project Manager Texas Commission on Environmental Murfee Engineering Company, Inc. Quality 1101 Capital of Texas Highway South Office of Chief Clerk, MC-105 D-100 P.O. Box 13087 Austin, Texas 78746 Austin, Texas 78711 FOR THE EXECUTIVE DIRECTOR REQUESTER(S) via electronic mail: Jonathan M. Beall Anthony Tatu, Staff Attorney Wilbarger Creek Conservation Alliance Texas Commission on Environmental 2503 Flora Cove Quality Austin, Texas 78746 Environmental Law Division, MC-173 P.O. Box 13087 Anne Stewart Brockenbrough Austin, Texas 78711 Elm Ridge Ranch Anthony.tatu@tceq.texas.gov 11318 Jones Road Manor, Texas 78653 Melinda Luxemburg, Technical Staff Texas Commission on Environmental Marilyn Kelinske Quality 15611 Littig Road Water Quality Division, MC-148 Manor, Texas 78653 P.O. Box 13087 Austin, Texas 78711 Marilyn Kelinske Melinda.luxemburg@tceq.texas.gov 6805 Ladera Norte Austin, Texas 78731 Ryan Vise, Deputy Director Texas Commission on Environmental Quality External Relations Division Public Education Program, MC-108 P.O. Box 13087 Austin, Texas 78711 AR Item 38, Page 012 Pep@tceq.texas.gov

Attachment A

AR Item 38, Page 013

SWWC Utilities

Map Requested by TCEQ Office of Legal Services Protecting Texas by Reducing and for Commissioners' Agenda Preventing Pollution Texas Commission on Environmental Quality GIS Team (Mail Code 197)

³ P.O. Box 13087 Austin, Texas 78711-3087 Date: 3/24/2023 CRF 0086257 290 Cartographer: cschrade

Requestors Outfall 1 mi Discharge Route 0.5 mi Radius 1.0 mi Radius 1.5 mi Radius

Distances Between Requestors and Outfall:

1) Anne Stewart Brockenbrough - 3.21 mi

2) Marilyn Kelinske - 2.89 mi

3) Johnathan M Beall - 15.65 mi

Source: The location of the facility was provided by the TCEQ Office of Legal Services (OLS). OLS obtained the site location information from the

Travis ! . applicant and the requestor information from the requestor. AR Item 38, Page 014 This map was generated by the Information Resources Division of the Texas Commission on Environmental Travis County Quality. This product is for informational purposes and may not have been prepared for or be suitable for legal, The facility is located in Travis County. The Circle (green) in engineering, or surveying purposes. It does not repre- sent an on-the-ground survey and represents only the the left inset map represents the approximate location of the facility. The inset map on the right represents the location of Travis 0 0.4 0.8 approximate relative location of property boundaries. County (red) in the state of Texas. Miles For more information concerning this map, contact the Information Resource Division at (512) 239-0800.

SWWC Utilities

Map Requested by TCEQ Office of Legal Services Protecting Texas by Reducing and for Commissioners' Agenda Preventing Pollution Texas Commission on Environmental Quality TX 360 GIS Team (Mail Code 197)

³ P.O. Box 13087 TX 275 Austin, Texas 78711-3087 Date: 3/24/2023 CRF 0086257 Cartographer: cschrade

TX 2222

Requestors 1 Outfall 1 mi Discharge Route 0.5 mi Radius 1.0 mi Radius 183 1.5 mi Radius

TX 111 Distances Between Requestors and Outfall:

1) Anne Stewart Brockenbrough - 3.21 mi

TX 343 2) Marilyn Kelinske - 2.89 mi TX 183

3) Johnathan M Beall - 15.65 mi

Source: The location of the facility was provided by the TCEQ Office of Legal Services (OLS).

st is OLS obtained the site location information from the

Ba rav p TX ! .

ro TX 71 applicant and the requestor information from the

T Travis requestor. AR Item 38, Page 015 This map was generated by the Information Resources Division of the Texas Commission on Environmental Travis County Quality. This product is for informational purposes and may not have been prepared for or be suitable for legal, The facility is located in Travis County. The Circle (green) in engineering, or surveying purposes. It does not repre- sent an on-the-ground survey and represents only the the left inset map represents the approximate location of the facility. The inset map on the right represents the location of Travis 0 1.5 3 approximate relative location of property boundaries. County (red) in the state of Texas. Miles For more information concerning this map, contact the Information Resource Division at (512) 239-0800.

Appendix Item 8 AR Item 34, Page 001 AR Item 34, Page 002 AR Item 34, Page 003 AR Item 34, Page 004 June 30, 2022

To: TCEQ Fm: Wilbarger Creek Conservation Alliance

Re: Majestic Manor WWTP Permit WQ0016022001

The WCCA hereby requests standing and submits the following comments concerning the Majestic Manor WWTP Permit Application.

Existing pollution upstream from the Kalinske Ranch on Wilbarger Creek at 15611 Littig Rd is causing a significant algae bloom as it flows east through the Kalinske Ranch.

We respectfully request the following actions by TCEQ - ● Wilbarger Creek already receives discharges from Shadow Glen and the City of Manor upstream of my property and that of 2 other WCCA Board members. ● Determine the cause of the existing algae bloom before adding more treated effluent. How does the TCEQ determine the cause of existing problems, and what effect will this information have on the new Majestic Manor permit? ● Pflugerville’s new WWTP is permitted to discharge 24 mgd. Since that plant is not online yet, We really don’t know what the upper reaches of the creek are going to look like in terms of stream flow and water quality after that plant goes online. WCCA requests the TCEQ include this effluent discharge in considering the Majestic Manor permit. ● If all of Pflugerville’s effluent is going to Wilbarger, it seems irresponsible to permit additional significant volumes of discharges before the true impacts of Pflugerville’s regional plant are more clear. ● The city of Pflugerville’s EIS says Wilbarger Creek supposedly has 15.75 MGD of capacity. Is all of this already accounted for in Pflugerville’s permit? If so, what is left for Majestic Manor? ● How will the additional discharge of Majestic Manor affect the overall health of Wilbarger Creek? ● Pre-existing conditions should determine the performance standards TCEQ requires for this new treatment plant. ● Does TCEQ have a good water quality baseline? If so, how current is it? The algae bloom seems to have appeared in the last 6 months.. ● WCCA requests a current baseline using samples taken during the past year. Please establish a current baseline by taking water quality samples above and below the discharge points of the 5 existing and proposed WWTPs on Wilbarger

AR Item 34, Page 005

Creek: Pflugerville, Shadowglen, Manor, Majestic Manor and Elgin. Wouldn’t it be prudent to do this now, prior to approval and construction of Majestic Manor? ● Wouldn’t such accurate and timely information help establish the necessary treatment standard for Majestic Manor? ● With the Pflugerville plant already permitted, we are looking at a situation where streamflow will be predominately treated effluent. Continuing to permit additional discharges gives the impression that Wilbarger should simply become a conduit for transporting treated wastewater down to the Colorado river. ● Impairment of Wilbarger Creek has been known for years. The out of date historical information contained in the 2012 water quality study linked below demonstrates impairment. We consider this kind of information, updated and current, vital to making the best decision on Majestic Manor. http://www.austintexas.gov/watershed_protection/publications/document.cfm?id=203919

We believe the treatment standards should be set at the highest possible and achievable limits. Wilbarger Creek should be maintained as a healthy, functioning ecosystem. Isn’t it easier and less expensive to prevent problems than to fix them in the future? To this end, we request the TCEQ consider requiring the most protective currently available treatment standards and techniques -

● A limit on total nutrient loading of 0.1 mg/liter phosphorus and 4 mg/liter nitrogen. Wastewater treatment technology is remarkable in terms of how well it can be done. This is a permit that requires it. ● Wet ponds, wetlands and sheet flow over a vegetated buffer - We request this technology on treated effluent prior to discharge into Wilbarger Creek. The use of a few acres devoted to these methods would significantly improve stream inputs. ● Land application - No discharge permits and land applications are required in the Highland Lakes and Barton Springs Zone. What justification is there to not have similar requirements in the Wilbarger Creek watershed? If developers can meet those requirements elsewhere, why shouldn't they do the same in the Wilbarger Creek watershed? ● Beneficial reuse - We appear to be entering another severe drought. Some of that water might be better used for irrigation, wetlands or other beneficial reuse. A reuse plan for Majestic Manor would preserve our potable water resources. Maybe now is the time to start including beneficial reuse in all permits? ● Chlorination is necessary to ensure harmful bacteria is killed. Unfortunately, the usual minimum residual levels in discharges is high enough to kill or stress fish and other aquatic life. If a portion of Wilbarger Creek is predominantly treated effluent, that portion of the Creek will not support much life. Irrigation or

AR Item 34, Page 006

discharging first to a pond or wetland prior to entering Wilbarger Creek could help mitigate that. ● Treatment plant malfunctions are unfortunately predictable, and sometimes outside the control of plant operators. Power outages, floods, mechanical failures, etc. can quickly result in exceedances of permit limits, even in a well run plant. Since Wilbarger creek is so small at this point, the impacts of an unauthorized discharge will be much more severe than a similar discharge into a larger river. Consider Round Rock’s problems at the Brushy Creek WWTP, which have been well documented over the last several months. Land application, beneficial reuse, etc. would provide a better buffer in the unfortunate event that the plant has problems. ● The unknown future negative impacts of Pflugerville’s WWTP and others indicate TCEQ should err on the side of caution. Downstream neighbors, taxpayers and aquatic environments should not have to suffer so that this wastewater operator can save a little money. ● The developers will make a lot of money. We urge the TCEQ to require the highest possible standards. The costs can be recovered in land sale prices.

In addition, WCCA requests -

● Standing for our organization to participate in the TCEQ process for Majestic Manor WWTP. ● Standing as individuals for three of the members of our WCCA Board who own significant stretches of both sides of Wilbarger Creek downstream of Majestic Manor: myself, Marilyn Kelinske, and Anne Brockenbrough. We request they be granted standing as individuals

Finally, the actual discharge point is not clear from the notice. It should be stated with more specificity in the application, but this detail is not in the public notice. It seems like an unreasonable burden to require us to obtain and read the entire application, just to see where this discharge is going to be.

Respectfully submitted, Jon Beall, President Wilbarger Creek Conservation Alliance

AR Item 34, Page 007 AR Item 34, Page 008 AR Item 34, Page 009 AR Item 34, Page 010 AR Item 34, Page 011 AR Item 34, Page 012 AR Item 34, Page 013 AR Item 34, Page 014 AR Item 34, Page 015 AR Item 34, Page 016 AR Item 34, Page 017 *18 5/10/24, 3:17 PM Wilbarger Creek Regional Wastewater Treatment Facility | City of Pflugerville, Texas Wilbarger Creek Regional Wastewater Treatment Facility

About this project Due to the City of Pflugerville's continued economic development, the City is actively working to expand water resources to maintain the highest level of service and quality of life to our residents.

The City owns a 159-acre tract of land on the west side of Wilbarger Creek and the north side of Gregg Lane that was selected to provide wastewater service to the Wilbarger and potentially the Cottonwood Sewer Basins. This land will be the location of the new Wilbarger Creek Regional Wastewater Treatment Facility (RWWTF).

The new facility will maximize the use of existing infrastructure while providing long-term facility expansion opportunities.

Based on updated flow projections, a strategic analysis of the Wilbarger service area has determined the following optimum facility size and expansion schedule for the Wilbarger Creek RWWTF:

Phase 1 – 6.00 MGD Phase 2 – 12.00 MGD Phase 3 – 15.75 MGD

Additional information The initial six (6) million gallon per day (MGD) phase of the treatment facility project includes an evaluation of wastewater treatment alternatives for site development.

The project will consist of preliminary engineering, design, bidding, and construction and is funded by the Texas Water Development Board (TWDB) Clean Water State Revolving Fund, which provides low-cost financial assistance for planning, acquisition, design, and construction of wastewater, reuse, and stormwater infrastructure.

TWDB funding was awarded in part due to the City's mission to consider environmentally responsible beneficial use strategies, such as reclaimed water, biosolids composting and potentially energy production in the future.

https://www.pflugervilletx.gov/city-government/capital-improvement-program-cip/projects-overview/wilbarger-creek-regional-wastewater-treatment-facility AR Item 34, Page1/6

5/10/24, 3:17 PM Wilbarger Creek Regional Wastewater Treatment Facility | City of Pflugerville, Texas

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5/10/24, 3:17 PM Wilbarger Creek Regional Wastewater Treatment Facility | City of Pflugerville, Texas

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CMAR Engagement Meeting

Overview The City of Pflugerville hosted a virtual Construction Manager At-Risk (CMAR) Engagement Meeting on January 11, 2023 from 8:30 - 10:30 a.m. to discuss the project which consists of construction of a greenfield 6.0 MGD wastewater treatment plant on a 158 acre site, including an influent lift station,

https://www.pflugervilletx.gov/city-government/capital-improvement-program-cip/projects-overview/wilbarger-creek-regional-wastewater-treatment-facility AR Item 34, Page3/6

5/10/24, 3:17 PM Wilbarger Creek Regional Wastewater Treatment Facility | City of Pflugerville, Texas

headworks, treatment trains for a 6.0 MGD secondary treatment system, tertiary filtration/UV disinfection, solids handling, building facilities, site civil improvements, and utilities.

The CMAR Request for Proposals (RFP) is anticipated for release on January 18, 2023, with receipt of proposals in March 2023 and planned Council Approval April 2023.

Meeting replay

CMAR - Contractor Outreach Wilbarger Creek …

Additional information

Watch on YouTube Download Transcript (VTT)

Virtual Open House

Overview In May 2021, the City hosted a virtual open house to share information on the proposed design and construction of the RWWTF.

Meeting replay

https://www.pflugervilletx.gov/city-government/capital-improvement-program-cip/projects-overview/wilbarger-creek-regional-wastewater-treatment-facility AR Item 34, Page4/6

5/10/24, 3:17 PM Wilbarger Creek Regional Wastewater Treatment Facility | City of Pflugerville, Texas

CMAR - Contractor Outreach Wilbarger Creek …

Additional information

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Related projects As separate projects, the City has authorized the design of the Wilbarger Creek Wastewater Interceptor (WWI) and the Sorento WWI Phase 2 projects. Once designed and constructed, both interceptors will deliver wastewater flows from the Wilbarger Basin for treatment to the Wilbarger Creek RWWTF. These projects are included in the established funding program with the TWDB.

Additional information Visit pflugervilletx.gov/projects and click on "In Design" under Utilities to learn more about these projects.

Project goals 1. To ensure quality wastewater services for Pflugerville residents. 2. Be an environmental steward with reliable wastewater filtration and best practices to protect Pflugerville creeks and waterways. 3. Produce a clean water discharge that continues to exceed regulatory standards and enhances the area habitat. 4. Operate and responsibly manage a wastewater facility that is sized to accommodate Pflugerville's current and future growth. https://www.pflugervilletx.gov/city-government/capital-improvement-program-cip/projects-overview/wilbarger-creek-regional-wastewater-treatment-facility AR Item 34, Page5/6

5/10/24, 3:17 PM Wilbarger Creek Regional Wastewater Treatment Facility | City of Pflugerville, Texas

Project updates The Wilbarger Creek RWWTF’s environmental information document (EID) has been reviewed by the TWDB and has been issued a Finding of no Significant Impact (FNSI). All three (3) of the City’s Wilbarger Creek Wastewater Improvement Program projects are continuing with design activities in parallel.

https://www.pflugervilletx.gov/city-government/capital-improvement-program-cip/projects-overview/wilbarger-creek-regional-wastewater-treatment-facility AR Item 34, Page6/6

AR Item 34, Page 024 AR Item 34, Page 025 AR Item 34, Page 026 AR Item 34, Page 027 AR Item 34, Page 028 AR Item 34, Page 029 AR Item 34, Page 030 AR Item 34, Page 031 AR Item 34, Page 032 AR Item 34, Page 033 AR Item 34, Page 034 AR Item 34, Page 035 AR Item 34, Page 036 AR Item 34, Page 037 Appendix Item 9 Appendix Item 10 Appendix Item 11

New Permit Review for Unclassified Waters by Standards Team

Name: SWWC Utilities, Inc. (Majestic Manor WWTP) Number: 16022001 County: Travis Region: 11 Basin: Colorado River Date Application Received: 7/28/21

1. Segment in Which Discharge is Located: 1434 – Colorado River Above La Grange

2. Designated Uses and Pertinent Criteria: PCR, PS, E, 6.0 mg/L DO

3. Unclassified Receiving Water Characteristics: Wilbarger Creek  >10 mi.  1434

The discharge is via pipe (~200 ft.) to the perennial portion of Wilbarger Creek per USGS, and previous review of permit #12900-001 and RWA (2005).

Outfall location: 30.3355, -97.53541

2020 303(d): 1434D_02 Wilbarger Creek, no impairments 2020 305(b): 1434D_02 Wilbarger Creek, bacteria and nitrate

4. Additional Comments: 0.2/0.5/0.8 MGD; proposed 5/5/2/1 limits are consistent with Colorado Watershed Protection Rule.

5. Recommended Receiving Water Uses and Associated Criteria:

Stream name Stream Aq. Life DO AL Criteria HH Criteria Order Use Acute Chron Incid. Sustain. HH-PS+ Fish Wilbarger Creek 3 H 5.0 X X X

6. Antidegradation: The nutrient screening indicates that a TP limit or monitoring may be warranted. The Colorado River Watershed Protection Rule will apply, and a total phosphorus limit of 1.0 mg/L TP will be required. This, combined with the relatively small size of the discharge, should help to preclude the potential for eutrophication. No significant degradation is expected.

7. Endangered species: Houston Toad in segment, but not county. Barton Springs salamander is in county, but not segment.

Reviewer: M. A. Wallace, PhD; 11/22/21

Peer reviewer, fill in the bold columns. Standards reviewer, fill in the non-bold columns. Date to Peer PR Date to SR Date to PR for Date to SR for Date to Crit Reviewer (PR) initial for Final Review Finalization Conditions reevaluation 11/22/21 BC 12/1/21 12/2/21 12/3/21 12/3/21

AR Item 37, Page 001

Nutrient Screening for Streams and Rivers (see pages 37 - 43 of the draft IPs) Applicant Name SWWC Permit number: 16022001 Segment: 1434

STEP 1: Determine evaluation distance. This a rough guide (page 37). Permitted flow (MGD) Evaluation distance (stream miles) <0.25 <3 0.25 to <1.0 <7 ≥ 1.0 <15

STEP 2: Assess concerns: enter point values in boxes to the right. HIGH (5 Specific notes on scores for Level of concern LOW (1 point) MOD (3 points) points) this permit. Discharge (MGD) <0.25 0.25 to <1.0 ≥1.0 3 Instream dilution (percent <10 10 to <25 ≥25 3 effluent)* Rocky cobble, gravel, Bottom (Sensitivity to Larger rocks and Mud or sand usually with some riffle 3 growth of attached algae) areas boulders, rock slabs

Depth (Sensitivity to Substantial shallow Relatively steep banks Gently sloping sides areas near banks growth of attached and deep channels with some shallow and in stream 3 vegetation) across streams areas channel Some turbidity, not Water clarity Turbid or tannic murky Clear water 3 Observation* (Sensitivity to growth of aquatic Little Limited/some Heavy patches 3 vegetation)

Shading (Sensitivity to Substantial canopy Canopy cover Extensive canopy cover but only partial diffuses light some, growth of aquatic cover shades most of shading; not "deep but substantial light 3 vegetaion) stream surface woods" reaches stream

Stream type Intermittent Intermittent with pools Perennial 5 No impoundments No impoundments At least one Impoundments >300' long, not many >300', substantial pools impoundment >300' 1 pools over 20% of reach

Some similar permits Discharges have TP limits, but w/similar Similar permits do not Consistency have TP limits applicability is site- characteristics 5 specific and not across usually have a TP the board limit No concern for Concern for nutrients or aquatic Documented Concern 305(b) and 303(d) veg in latestet exceedance of 85th problems 3 percentile integrated report Sum: 0 Average: 3.18

Average <2, probably no TP limit needed Average >4, TP limit probably needed Average 2-4, TP monitoring or a limit is possible, depending. If a TP limit is needed, screening factors and levels of concern can be used to determine the TP limit.

AR Item 37, Page 002 Appendix Item 12

Procedures to Implement the Texas Surface Water Quality Standards

Prepared by Water Quality Division

RG-194 June 2010

Contents Introduction................................................................................................. 12

Determining Water Quality Uses and Criteria........................................ 14 Classified Waters .......................................................................................................... 14 Unclassified Waters ...................................................................................................... 14 Presumed Aquatic Life Uses......................................................................................... 14 Assigned Aquatic Life Uses...................................................................................... 16

Evaluating Impacts on Water Quality...................................................... 20 General Information...................................................................................................... 20 Minimum and Seasonal Criteria for Dissolved Oxygen ............................................... 21 Federally Endangered and Threatened Species ............................................................ 21 Screening Process ..................................................................................................... 22 Additional Permit Limits .......................................................................................... 22 Edwards Aquifer ....................................................................................................... 23 Bacteria ......................................................................................................................... 24 Recreational Uses and Criteria.................................................................................. 24 Assigning Recreational Uses .................................................................................... 25 Wastewater Permitting.............................................................................................. 26 Nutrients........................................................................................................................ 26 Introduction............................................................................................................... 26 General Screening Approach for Nutrient Impacts .................................................. 26 Nutrient Screening for Main Pool Effects in Reservoirs with Numerical Nutrient Criteria ...................................................................................................................... 30 Nutrient Screening for Local Effects in Reservoirs.................................................. 38 Nutrient Screening for Streams and Rivers .............................................................. 47 Nutrient Screening for Estuaries............................................................................... 53 Other Applicable Rules................................................................................................. 53

Antidegradation .......................................................................................... 55 Policy ............................................................................................................................ 55 General Applicability.................................................................................................... 55 Tier 1—Protecting Uses................................................................................................ 56 Protecting Impaired Waters under Tier 1...................................................................... 57 Definitions................................................................................................................. 57 General Provisions .................................................................................................... 58 Applicability to Specific Parameters ........................................................................ 58 Procedures for Discharges to Listed Water Bodies .................................................. 59 Applicability of Pollution Reduction Programs........................................................ 60 Examples of Permitting to Listed Water Bodies....................................................... 60

Tier 2—Protecting High-Quality Waters...................................................................... 61 Applicability ............................................................................................................. 61 Evaluating the Potential for Degradation of Water Quality...................................... 63 Examples Where Degradation Is Unlikely to Occur................................................. 65 Examples Where Degradation Is Likely to Occur .................................................... 66 Evaluation of Alternatives and Economic Justification............................................ 66 Agency Review of Degradation................................................................................ 67 Tier 3—Outstanding National Resource Waters .......................................................... 67 Watershed Protection Rules.......................................................................................... 68 Public Notice................................................................................................................. 69

Mixing Zones and Critical Conditions...................................................... 70 General Information...................................................................................................... 70 Mixing Zones and ZIDs for Aquatic Life Protection.................................................... 70 Critical Conditions for Aquatic Life Protection............................................................ 72 Determining the 7Q2..................................................................................................... 75 Determining Critical Low-Flows for Streams and Rivers that are Dominated by Springflow..................................................................................................................... 77 Mixing Zones and Critical Conditions for Human Health Protection .......................... 78 Determining the Harmonic Mean Flow ........................................................................ 80 Diffusers........................................................................................................................ 82

Modeling Dissolved Oxygen....................................................................... 83 General Information...................................................................................................... 83 Model Selection and Inputs .......................................................................................... 83 Screening Level Methods ............................................................................................. 84 Nontidal Streams and Rivers .................................................................................... 84 Tidal Water Bodies, Ponds, and Lakes ..................................................................... 87 Critical Low-Flow Values for East and South Texas Streams ..................................... 88 Regression Equation Relating Dissolved Oxygen, Flow, and Bedslope .................. 91 Calculating Bedslope ................................................................................................ 92 Guidelines for Adjusting the Regression Equation................................................... 92 Regression Equation for Establishing Critical Low-Flows in Specific Water Bodies in the Cypress Creek Basin ....................................................................................... 93 Water Bodies with a Dissolved Oxygen Impairment ................................................... 94

Whole Effluent Toxicity Testing (Biomonitoring)................................. 102 Applicability ............................................................................................................... 102 Chronic and 48-Hour Acute Tests .............................................................................. 104 Test Types............................................................................................................... 104 Test Acceptability Criteria...................................................................................... 105 Statistical Interpretation of Test Results ................................................................. 107 Test Frequencies ..................................................................................................... 108 Dilution Series, Dilution Water, and Type of WET Test ....................................... 110 Reasonable Potential Determination....................................................................... 113

Toxicity Reduction Evaluations (TREs)................................................................. 115 24-Hour Acute (100% End-of-Pipe) Tests ................................................................. 118 Test Types............................................................................................................... 118 Test Acceptability Criterion.................................................................................... 119 Test Frequencies ..................................................................................................... 119 Toxicity Reduction Evaluations (TREs)................................................................. 119 Toxicity Control Measures ..................................................................................... 121 Test Substitution ......................................................................................................... 122 Toxicity Attributable to Dissolved Salts..................................................................... 122 TDS Exemption—24-Hour Acute (100% End-of-Pipe) Tests ............................... 125 TDS Exemption—Chronic and 48-Hour Acute Tests ............................................ 126 Ammonia Toxicity ...................................................................................................... 128 Controlling Potential Ammonia Toxicity ............................................................... 128 Toxicity Attributable to Ammonia.......................................................................... 129 Toxicity Attributable to Diazinon............................................................................... 129

Toxic Pollutants......................................................................................... 130 General Provisions ...................................................................................................... 130 Specific Numerical Criteria ........................................................................................ 131 Deriving Permit Limits for Aquatic Life Protection................................................... 132 General Approach ................................................................................................... 132 Water Quality Parameters That Affect Aquatic Life Criteria................................. 132 Calculating Effluent Fractions ................................................................................ 133 Calculating Waste Load Allocations ...................................................................... 135 Calculating the Long-Term Average ...................................................................... 136 Calculating Daily Average and Daily Maximum Permit Limits ............................ 137 Deriving Permit Limits for Human Health Protection................................................ 140 General Approach ................................................................................................... 140 Calculating the Effluent Fraction............................................................................ 141 Calculating the Waste Load Allocation .................................................................. 142 Calculating the Long-Term Average and Permit Limits ........................................ 142 Establishing Permit Limits for Toxic Pollutants without Criteria .............................. 143 Aquatic Life Criteria ............................................................................................... 143 Human Health Criteria............................................................................................ 146 Correcting for Background Concentrations ................................................................ 148 Procedure for Developing Permit Limits................................................................ 148 Obtaining Reliable Water Quality Data.................................................................. 152 Once-Through Cooling Water Discharges.................................................................. 153 Applicability ........................................................................................................... 153 Permit Action .......................................................................................................... 153 Statistical Study ...................................................................................................... 154 Source Investigation................................................................................................ 155 Exemption Approval or Denial............................................................................... 155 Collecting Site-Specific Data...................................................................................... 156 Hardness, pH, and Chloride .................................................................................... 156 TSS, Partition Coefficients, and Bioavailable Fractions of Metals ........................ 159 Calculating Permit Limits for Specific Toxic Pollutants............................................ 164

Calculating Permit Limits for Mercury, PCBs, Dioxins/Furans, DDT, DDD, and DDE ........................................................................................................................ 164 Calculating Permit Limits for Silver....................................................................... 166 Calculating Permit Limits for Chromium ............................................................... 167 Establishing Permit Limits for Toxic Pollutants......................................................... 168 Application Screening............................................................................................. 168 Analytical Procedures and MALs........................................................................... 169 Alternate Test Procedures ....................................................................................... 172 Defining Permit Limits ........................................................................................... 173

Screening Procedures and Permit Limits for Total Dissolved Solids.. 174 Introduction................................................................................................................. 174 Screening Procedures for TDS.................................................................................... 175 Determining Site-Specific Ambient TDS Values ....................................................... 180 Establishing Permit Limits for TDS ........................................................................... 181 Final Evaluation and Additional Considerations for TDS.......................................... 184

TPDES Storm Water Permits.................................................................. 187 General Provisions ...................................................................................................... 187 Reviewing Permit Applications .................................................................................. 187 Site-Specific Information............................................................................................ 189 Antidegradation Review of Storm Water Permits ...................................................... 189 Discharges to Impaired Waters................................................................................... 189 Discharges to the Edwards Aquifer Recharge Zone ................................................... 190 Discharges to Specific Watersheds and Water Quality Areas .................................... 190

Site-Specific Standards and Variances ................................................... 191 General Provisions ...................................................................................................... 191 Interim Permit with a Variance................................................................................... 191 Variance Extensions.................................................................................................... 192 Coordinating with EPA............................................................................................... 193 Temporary Standards .................................................................................................. 194 Site-Specific Standards for Aquatic Life Use............................................................. 195 Aquatic Life UAA Review and Approval .............................................................. 196 Aquatic Life UAAs for Typical Sites ..................................................................... 197 Site Complications Requiring Additional Justification .......................................... 199 Site-Specific Standards for Recreational Use ............................................................. 199 Recreational UAA Review and Approval............................................................... 200 How to Conduct Recreational UAAs...................................................................... 201 Wildlife Sources of Bacteria................................................................................... 202 Site-Specific Numerical Standards for Aquatic Life .................................................. 202 Site-Specific Standards for Total Toxicity ................................................................. 207

Appendix A. Playa Lake Policy Statement............................................. 209

Appendix B. Locations of Federally Endangered and Threatened Aquatic and Aquatic-Dependent Species in Texas ................................ 211

Appendix C. Critical Low-Flows and Harmonic Mean Flows for Classified Segments................................................................................... 217

Appendix D. Segment-Specific Values for Total Suspended Solids, pH, Total Hardness, Total Dissolved Solids, Chloride, and Sulfate............ 228

Appendix E. Minimum Analytical Levels and Suggested Analytical Methods...................................................................................................... 244

Appendix F. Nutrient Screening Parameters for Certain Reservoirs. 270 Appendix G. Transfer of Analytes. ......................................................... 279 *7 Figures Figure 1. Flow chart showing the nutrient screening procedure....................................... 28

Figure 2. Relationship of mean chlorophyll a concentration to mean total phosphorous concentration in reservoirs................................................................................................ 35

Figure 3. Headwater flows for streams in area “A” may be adjusted based on Table 4.. 89 Figure 4. Chronic and 48-Hour WET Testing Frequencies........................................... 109 Figure 5. Procedure for Addressing WET Limit Violations.......................................... 117

Figure 6. Procedure for Exemption from Total Toxicity Requirements because of Dissolved Salts................................................................................................................ 124

Figure 7. Probability Distribution that Describes Treatment System Performance....... 136 Figure 8. Derivation of Equations Used to Calculate the Long-Term Average ............ 138

Figure 9. Derivation of Equations Used to Calculate Daily Average and Daily Maximum Concentration Limits ...................................................................................................... 139

Figure 10. Protocol for Including Background Concentrations in Permit Limit Calculations..................................................................................................................... 151

Figure 11. Establishing Permit Limits for Total Dissolved Solids ................................ 182 *8 Tables Table 1. Aquatic Life Use Subcategories ........................................................................ 15 Table 2. Estimated Extent of Downstream DO Impact from Discharge ......................... 17

Table 3. Segments that Cross the Contributing and Recharge Zones of the Southern Section of the Edwards Aquifer ............................................................. 23

Table 4. Critical Low-Flow Values for Dissolved Oxygen for East and South Texas ................................................................................................. 90

Table 4a. Critical Low-Flow Values for Dissolved Oxygen for Harrison Bayou, in Segment 0401. ............................................................................ 95

Table 4b. Critical Low-Flow Values for Dissolved Oxygen for Black Bayou, Segment 0406. ..................................................................................... 96

Table 4c. Critical Low-Flow Values for Dissolved Oxygen for James Bayou, Segment 0407...................................................................................... 97

Table 4d. Critical Low-Flow Values for Dissolved Oxygen for Little Cypress Creek (Bayou), Segment 0409............................................................ 98

Table 4e. Critical Low-Flow Values for Dissolved Oxygen for Black Cypress Bayou (Creek), Segment 0410 and Black Cypress Bayou (Creek) upstream of Segment 0410...................................... 99

Table 5. Background Concentrations of Toxic Metals in Texas Estuaries.................... 150

Table 6. Slope (m) and Intercept (b) Values Used to Calculate Partition Coefficients for Metals in Streams, Lakes, and Estuarine Systems ................ 160

Table 7. Summary of TDS Screening and Limit Calculation Methods......................... 186 *9 Abbreviations

Abbreviation Full Name ACR acute-to-chronic ratio AU assessment unit BAF bioaccumulation factor BAT best available technology BCF bioconcentration factor BMP best management practice BOD biochemical oxygen demand BPJ best professional judgment CASRN Chemical Abstracts Service Registry Number CBOD carbonaceous biochemical oxygen demand CFR Code of Federal Regulations CIU categorical industrial user CPP Continuing Planning Process CRQL contract required quantitation level CSTR continuously stirred tank reactor CV coefficient of variation CWA Clean Water Act DO dissolved oxygen EPA Environmental Protection Agency FR Federal Register GIS geographic information system HM harmonic mean flow HUC hydrological unit code IBWC International Boundary and Water Commission IU industrial user LTA long-term average MAL minimum analytical level MCL maximum contaminant level MDL method detection limit MGD million gallons per day ML minimum level MOA memorandum of agreement

Abbreviation Full Name MQL minimum quantitation level MS4 municipal separate storm sewer system MSDS material safety data sheet MZ mixing zone NCR noncontact recreation NH3-N ammonia-nitrogen NOE Notice of Enforcement NOEC no observable effects concentration NPDES National Pollutant Discharge Elimination System 1Q2 one-day, two-year low-flow ONRW outstanding national resource water PCR primary contact recreation PMSD percent minimum significant difference QSAR quantitative structure-activity relationship RP reasonable potential RWA receiving water assessment SCR secondary contact recreation 7Q2 seven-day, two-year low-flow SIU significant industrial user SM Standard Methods SMAV species mean acute value SOD sediment oxygen demand SPIF supplemental permit information form SWMP storm water management plan SWP3 storm water pollution prevention plan SWQM Surface Water Quality Monitoring SWQMIS Surface Water Quality Monitoring Information System TAC Texas Administrative Code TBD to be determined TCEQ Texas Commission on Environmental Quality TDS total dissolved solids TEAC Texas Environmental Advisory Council TEF toxic equivalency factor TEQ toxic equivalence TIE toxicity identification evaluation TMDL total maximum daily load

Abbreviation Full Name TN total nitrogen TNRCC Texas Natural Resource Conservation Commission TP total phosphorus TPDES Texas Pollutant Discharge Elimination System TPWD Texas Parks and Wildlife Department TRE toxicity reduction evaluation TSS total suspended solids TWDB Texas Water Development Board UAA use-attainability analysis U.S.C. United States Code USFWS United States Fish and Wildlife Service USGS United States Geological Survey WER water-effect ratio WET whole effluent toxicity WLA waste load allocation WLE waste load evaluation WQMP Water Quality Management Plan ZID zone of initial dilution

Introduction

The Texas Commission on Environmental Quality (TCEQ) is responsible for maintaining and enhancing water quality in the state. The Texas Surface Water Quality Standards, which are the legal standards for the quality of surface water in Texas, are described in Title 30 of the Texas Administrative Code (TAC) Chapter 307. 1

The TCEQ applies these Standards when issuing permits for wastewater discharges or other authorized discharges to the surface waters of the state. Wastewater permits are issued under a program called the Texas Pollutant Discharge Elimination System—TPDES.

Who should read this document? This document explains procedures the TCEQ uses when applying the Standards to permits issued under the TPDES program. This information should be of interest to regulated facilities that discharge wastewater (for example, domestic sewage treatment plants and industrial plants), to environmental professionals who help such facilities obtain their permits, and to other environmental professionals interested in wastewater permitting. The TCEQ will update this guidance document as needed to reflect changes in the Standards and in agency policy and procedures. This document should be interpreted as guidance and not as a replacement to the rules.

Document approval. This document was approved by the TCEQ on [new date]. It was also subject to Environmental Protection Agency (EPA) review and approval in accordance with the memorandum of agreement (MOA) between the TCEQ and EPA concerning the TPDES program. In a letter dated [new date], EPA approved this document.

For more information concerning revisions to the Standards and to this document, visit the Texas Surface Water Quality Standards page (www.tceq.state.tx.us/nav/eq/eq_swqs.html) and follow the Link: “Future Revisions of the Texas Surface Water Quality Standards.”

Application review. The TCEQ believes that a consistent approach to application review is important. A permit applicant may provide information throughout the technical review to assist TCEQ staff in site- specific assessment and draft permit development. All preliminary determinations by TCEQ staff in the development of a permit (for example, instream uses, impact analysis, antidegradation, effluent limits, and all other specifications of the permit) are subject to additional review

1 On [new date], the TCEQ adopted the most recent revision to Chapter 307, Texas Surface Water Quality Standards.

and revision through the public hearing process. Case-by-case permitting decisions are subject to EPA review and approval in accordance with the MOA between the TCEQ and EPA concerning the TPDES program.

For more information. Implementing the Standards in the TPDES program is just one aspect of the TCEQ’s overall program for water quality management. A series of documents, the Continuing Planning Process (CPP), details the agency’s policies and procedures to protect and maintain water quality, in fulfillment of the state’s responsibilities under federal law. For more information about the overall program, visit the “Continuing Planning Process” page (www.tceq.state.tx.us/implementation/water/planning/CPPMain.html).

A list of abbreviations used throughout this document is provided in the front of this document on page 9.

References in this document to tables or appendices should be understood to mean tables or appendices in this document unless another document is specified, such as the Standards.

Determining Water Quality Uses and Criteria

Classified Waters Classified waters are those water bodies that are designated as segments in Appendix A of the Standards. Classified segments have designated uses (such as recreation, aquatic life, and water supply) and criteria associated with those uses (such as dissolved minerals, dissolved oxygen, pH, bacteria, and temperature). The designated uses and associated criteria are listed in Appendix A of the Standards and are used to evaluate wastewater permit applications.

Unclassified Waters Unclassified waters are those smaller water bodies that are not designated as segments in Appendix A of the Standards. Certain unclassified water bodies are listed in Appendix D of the Standards. These are water bodies where sufficient information has been gathered to assign an aquatic life use and associated dissolved oxygen criterion. Water bodies listed in Appendix D are not designated as classified segments. Unclassified water bodies not included in Appendix D are assigned presumed aquatic life uses (as described in § 307.4(h) of the Standards) during reviews of wastewater permit applications.

In addition to aquatic life uses, unclassified waters can be assigned uses for primary, secondary, or noncontact recreation and domestic water supply. Basic uses such as navigation, agricultural water supply, and industrial water supply are normally assumed for all waters. Presumed recreational uses and bacteria criteria for unclassified water bodies, including those in Appendix D, are described in § 307.4(j) of the Standards.

Presumed Aquatic Life Uses The characteristics and associated dissolved oxygen criteria for exceptional, high, intermediate, and limited aquatic life use subcategories are contained in Table 1 below. This table also includes associated dissolved oxygen criteria for a minimal aquatic life use subcategory, which applies to intermittent streams without perennial pools.

Table 1. Aquatic Life Use Subcategories

AQUATIC LIFE USE Exceptional High Intermediate Limited Minimal SUBCATEGORY Freshwater mean/ 6.0/4.0 5.0/3.0 4.0/3.0 3.0/2.0 2.0/1.5 minimum DISSOLVED Freshwater in OXYGEN Spring mean/ 6.0/5.0 5.5/4.5 5.0/4.0 4.0/3.0 — CRITERIA minimum (mg/L) Saltwater mean/ 5.0/4.0 4.0/3.0 3.0/2.0 — — minimum Outstanding Habitat Highly Moderately natural Uniform — Characteristics diverse diverse variability Usual Most association Some regionally Species Exceptional of regionally expected expected — Assemblage or unusual expected species species AQUATIC species absent LIFE Sensitive Very low in Abundant Present Absent — ATTRIBUTES Species abundance Exceptionally Diversity High Moderate Low — high Species Exceptionally High Moderate Low — Richness high Balanced to Trophic Moderately Severely Balanced slightly — Structure imbalanced imbalanced imbalanced NOTE: Information in this table is taken from Table 3 in § 307.7(b)(3)(A) of the Standards.

Perennial Waters As stated in § 307.4(h)(3) of the Standards, unclassified perennial streams that are not listed in Appendix D of the Standards, rivers, lakes, bays, estuaries, and other appropriate perennial waters are presumed to have a high aquatic life use and corresponding dissolved oxygen criterion. Higher uses will be maintained where they are attainable.

Intermittent Streams Intermittent streams are defined as having either

• • a period of zero flow for at least one week during most years or • a seven-day, two-year low-flow (7Q2) less than 0.1 ft3/s (where flow records are available).

According to § 307.4(h)(4) of the Standards, unclassified intermittent streams that are not specifically listed in Appendix A or D of the Standards are considered to have a minimal aquatic life use, except as indicated below in this paragraph, and will maintain a 24-hour mean

dissolved oxygen concentration of 2.0 mg/L and an absolute minimum dissolved oxygen concentration of 1.5 mg/L. For intermittent streams with seasonal aquatic life uses, dissolved oxygen concentrations commensurate with those aquatic life uses will be maintained during the seasons in which the aquatic life uses occur.

Intermittent Streams with Perennial Pools Unclassified intermittent streams with perennial pools are presumed to have a limited aquatic life use and corresponding dissolved oxygen criterion (See Table 1). Higher uses will be maintained where they are attainable.

At this time, determination of what constitutes a seasonal aquatic life use and perennial pool designation is done on a case-by-case basis using available data and best professional judgment. The TCEQ will continue to develop improved procedures to address the issues of seasonal aquatic life use and perennial pools.

Playa Lakes The applicability of the Standards and the appropriate aquatic life use designation for playa lakes is discussed in the Playa Lake Policy Statement that was signed by the agency’s executive director on October 20, 1997 (See Appendix A on page 209 of this document).

Assigned Aquatic Life Uses Aquatic life uses and corresponding dissolved oxygen (DO) criteria are assigned to waters that have the potential to be affected by permitted wastewater discharges. The DO criteria are used to evaluate the results of DO modeling performed to determine the effluent limits needed to protect the uses. (For more information, see the chapter of this document entitled “Modeling Dissolved Oxygen” on page 83.)

Staff uses Table 2 below to estimate how far downstream to assign uses for discharges to streams or rivers. The distances in the table are based on default dissolved oxygen modeling of a single discharge and represent twice the distance to the predicted bottom of the dissolved oxygen sag. Uses are assigned farther downstream when site-specific stream data indicate that the impact from a discharge extends a greater distance than indicated in Table 2.

Table 2. Estimated Extent of Downstream DO Impact from Discharge

Permitted Flow Estimated Impact (MGD) Distance (miles) ≤ 0.05 0.60 > 0.05 to ≤ 0.10 0.75 > 0.10 to ≤ 0.20 1.0 > 0.20 to ≤ 0.50 1.1 > 0.50 to ≤ 1.0 2.0 > 1.0 to ≤ 2.0 2.7 > 2.0 to ≤ 3.5 2.9 > 3.5 to ≤ 5.0 3.2 > 5.0 to ≤ 7.5 5.0 > 7.5 to ≤ 10 6.0 > 10 to ≤ 15 7.7 > 15 to ≤ 20 9.2 > 20 to ≤ 40 15.3

Uses and associated criteria for unclassified waters are either in Appendix D of the Standards or have to be assigned when those waters have the potential to be affected by permitted wastewater discharges (see § 307.4(l) of the Standards). Assignments of aquatic life use categories are based on characteristics shown in Table 1 on page 16. Please note the following:

• • Site-specific modification of the aquatic life criteria in Table 1 may be considered when sufficient information is available to justify such modifications. Site-specific modifications are evaluated in accordance with guidance for regional development of criteria or other procedures used by TCEQ (See the chapter of this document entitled “Site- Specific Standards and Variances” on page 191).
• • The attribute characteristics in Table 1 will be further clarified, modified, and “calibrated” as more region-specific data become available.

All permit applicants are requested to provide information about the receiving water as part of the permit application. Determining general stream flow characteristics (perennial, intermittent, or intermittent with perennial pools) is of major importance in assigning uses to unclassified streams. Permittees with discharges to small unclassified streams are encouraged to develop and submit additional documentation concerning the general stream type and stream flows at their discharge site.

TCEQ staff evaluates available information and determine appropriate uses and criteria for each permit action for discharge into surface water in the state. For sites where available information indicates that the presumed uses and criteria in the Standards may be inappropriate, additional data may be obtained by the TCEQ or the applicant in the form of a receiving water assessment (RWA). Guidelines for collecting the additional data and evaluating aquatic life uses for RWAs are described in the most recent versions of the TCEQ’s Surface Water Quality Monitoring Procedures, RG-415 and RG-416. These documents are available on the agency’s Web site (www.tceq.state.tx.us); follow the link for “Publications.”

TCEQ staff considers hydrological conditions, appropriate assessment location, and applicability when determining the aquatic life uses for water bodies that receive or may receive a permitted wastewater discharge.

• • TCEQ staff determines aquatic life use for the same set of hydrological conditions (normally stream low-flow and high temperatures, or critical conditions) that are used to analyze the impact of permitted discharges. These determinations may consider seasonal uses and associated hydrological conditions other than critical conditions. Permit limits are established as necessary to protect seasonal uses in both intermittent and perennial streams.
• • TCEQ staff determines which part of a stream to assess depending on whether the discharge already exists or is not yet occurring.

◦ For existing dischargers seeking permit renewals or amendments, TCEQ staff will give more weight to physical, hydrological, chemical, and biological conditions upstream of or in an area unaffected by an existing discharge. Staff will also consider differences in stream morphometry downstream of the discharge when determining appropriate aquatic life uses.

◦ For new dischargers or facilities that have not yet discharged, TCEQ staff will give more weight to physical, hydrological, chemical, and biological conditions downstream of the proposed discharge point.

• • For freshwater streams, the aquatic life use attributes are evaluated primarily from the use of an index of biotic integrity as described in the most recent version of TCEQ’s Surface Water Quality Monitoring Procedures, Volume 2: Methods for Collecting and Analyzing Biological Assemblage and Habitat Data, RG-416. Other water body types are evaluated on a case-by-case basis.
• • The uses assigned to unclassified waters at a particular discharge site are not automatically assumed to be appropriate for other discharge sites in the same water body.

Unclassified waters with sufficient information obtained under these procedures will be considered for inclusion in Appendix D during the triennial review of the Standards.

When an attainable aquatic life use for a particular unclassified water body might be lower than the presumed aquatic life use, a use-attainability analysis (UAA) is conducted (See the section of this document entitled “Site-Specific Standards for Aquatic Life Use” on page 195).

TCEQ staff may review the preliminary determinations of use and the criteria associated with those uses throughout the permit application review if, new information becomes available and/or if there are errors in the previous evaluations. The applicant is given an opportunity to discuss the preliminary determinations of use and provide additional information after receiving the draft permit for review. The Notice of Application and Preliminary Decision indicates any preliminary additional uses assigned to the unclassified receiving waters.

Evaluating Impacts on Water Quality

General Information New permit applications, permit renewals, and permit amendments are reviewed to ensure that permitted effluent limits will maintain instream criteria for dissolved oxygen and other parameters such as bacteria, phosphorus, nitrogen, turbidity, dissolved solids, temperature, and toxic pollutants. The assessment of appropriate aquatic life uses and dissolved oxygen criteria is conducted as discussed in the previous chapter, “Determining Water Quality Uses and Criteria” (see page 14).

TCEQ staff review all available information from sources that may include (but are not limited to) the permit application, stream surveys, routine monitoring information, waste load evaluations (WLEs), or total maximum daily loads (TMDLs). Additional information may also be acquired from the TCEQ’s regional staff, the applicant, adjacent land owners, river authorities, or governmental entities.

All proposed permit actions that would increase pollution are also evaluated using the procedures discussed in the chapter of this document entitled “Antidegradation” on page 55.

The impact of discharges on endangered and threatened species is considered in accordance with the memorandum of agreement (MOA) between the TCEQ and the EPA and with the biological opinion from the U.S. Fish and Wildlife Service (USFWS). For more information, see the section of this document entitled “Federally Endangered and Threatened Species” on page 21.

Waste load evaluation recommendations and TMDLs are incorporated into permit limits for discharges into segments with completed WLEs or calculated TMDLs. For receiving waters without specific WLEs or TMDLs, oxygen deficit models or other appropriate analyses are conducted to determine permit limits. See the chapter of this document entitled “Modeling Dissolved Oxygen” on page 83.

Throughout any permit hearing process, TCEQ may continue to evaluate water quality impacts of permitted discharges and revise permit effluent limits based on these evaluations. Such evaluations and revisions may also be subject to EPA review and approval.

Minimum and Seasonal Criteria for Dissolved Oxygen Instantaneous minimum dissolved oxygen criteria (from Table 1 of this document―see page 16) and seasonal dissolved oxygen criteria are also considered. When determining seasonal permit limits, TCEQ staff generally use either a low-flow frequency or a seasonal 7Q2 and associated temperatures to estimate critical conditions in a particular month or season. For more detailed information, see the discussion on critical conditions used in modeling on page 85 of the “Modeling Dissolved Oxygen” chapter.

Federally Endangered and Threatened Species The TCEQ reviews permit applications to determine whether discharges could potentially have any adverse effect on an aquatic or aquatic- dependent federally endangered or threatened species, including proposed species. The TCEQ may also consider potential adverse affects to state- listed species and will coordinate with Texas Parks and Wildlife Department (TPWD) as needed. Information that is considered during the review includes the following:

• • the MOA between the TCEQ and the EPA concerning the TPDES program, available on the agency’s Web site (www.tceq.state.tx.us); 2
• • the USFWS biological opinion (dated September 14, 1998) associated with assumption of the TPDES program by the State of Texas; and
• • an update to that biological opinion (dated October 21, 1998).

The USFWS biological opinion includes a list of the United States Geological Survey (USGS) hydrological unit codes (HUCs) that cover the watersheds that should be considered in determining whether a listed species could be affected. These HUCs have been matched to both the counties and the classified segments into which the watersheds drain. Subsequent information from the USFWS has identified some specific water bodies where species of critical concern are known to occur. USFWS is informally notified, by way of a supplemental permit information form (SPIF), of all permit applications declared administratively complete.

2 Go to the TCEQ Web site and follow these links: “Permits, Registrations” “Water Quality Permits” “Water Quality Permits for Cities and Other Developed Areas” “Wastewater Pretreatment: Requirements and Options” “TPDES Permit: Pretreatment Requirements” “What Is the ‘Texas Pollutant Discharge Elimination System (TPDES)’?” “Authorization” “Memorandum of Agreement between the TNRCC (TCEQ) and USEPA Region 6”

Screening Process After permit applications are declared administratively complete, TCEQ staff screen them as follows:

1. The first classified segment that the discharge enters is determined.

2. The list of segments in Appendix B on page 211 (taken from Appendix A of the USFWS biological opinion and subsequent updates) is consulted to determine whether there is a potential for the listed species to occur anywhere within the watershed of the segment or whether the listed species is known to be only in a particular water body.

3. If the species has a potential of occurring anywhere within the watershed of the segment, TCEQ staff may compare the location of the discharge against the HUCs listed in the biological opinion to more accurately determine whether the discharge may impact listed species.

Note that TCEQ staff also screen applications from petroleum facilities south of Copano Bay (Segment 2472) to determine whether these discharges could potentially have any adverse effect on the piping plover, a species of high priority.

4. If the application screening indicates that the discharge has a potential to affect a listed species, USFWS is formally notified via either the SPIF or the Notice of Application and Preliminary Decision.

5. TCEQ staff performs further reviews of discharges that are formally reported to USFWS in step 4 to determine whether additional or more stringent permit limits are necessary. In making this determination, the location of the discharge within the county, the distance from the segment or water body in question, the size of the discharge, and the type of species (for example, fish, amphibian, invertebrate, or plant) are all considered.

Additional Permit Limits The TCEQ may require additional permit limits for discharges that TCEQ staff determine have a high potential to adversely affect listed species of critical concern. Examples of such discharges include:

• • discharges directly to watersheds in which listed species occur. • discharges whose dissolved oxygen sag extends into watersheds where listed species occur.

These types of discharges are issued permits that, if necessary, require dechlorination and contain a daily average ammonia-nitrogen limit of 3.0

mg/L or less. Additional permit limits may be imposed based on USFWS concerns and other issues as they arise.

Edwards Aquifer Discharges within and across the contributing and recharge zones of the southern section of the Edwards Aquifer are reviewed to determine whether there will be any effects on threatened and endangered fish, amphibian, invertebrate, or plant species occurring down-gradient from the discharge. The review may include input from TCEQ staff knowledgeable in groundwater and hydrogeology.

Table 3 lists the classified segments that cross the contributing and recharge zones of the southern section of the Edwards Aquifer. This list of segments corresponds to the true geological zones that cover the entire watersheds containing those segments. This list is not identical to the segments covered in 30 TAC Chapter 213 (in Medina, Bexar, Comal, Kinney, Uvalde, Hays, Travis, and Williamson Counties) or to those segments having an assigned aquifer protection use in Appendix A of the Standards.

Table 3. Segments that Cross the Contributing and Recharge Zones of the Southern Section of the Edwards Aquifer

Segment Number Segment Name 1427 Onion Creek 1430 Barton Creek 1804 Guadalupe River Below Comal River 1805 Canyon Lake 1806 Guadalupe River Above Canyon Lake 1808 Lower San Marcos River (above City of Martindale) 1809 Lower Blanco River 1810 Plum Creek 1811 Comal River 1812 Guadalupe River Below Canyon Dam 1813 Upper Blanco River 1814 Upper San Marcos River 1815 Cypress Creek 1816 Johnson Creek 1817 North Fork Guadalupe River 1818 South Fork Guadalupe River 1903 Medina River Below Medina Diversion Lake 1904 Medina Lake

Segment Number Segment Name 1905 Medina River Above Medina Lake 1906 Lower Leon Creek 1907 Upper Leon Creek 1908 Upper Cibolo Creek 1909 Medina Diversion Lake 1910 Salado Creek 2111 Upper Sabinal River 2112 Upper Nueces River (upper portion) 2113 Upper Frio River 2114 Hondo Creek 2115 Seco Creek

Bacteria Recreational Uses and Criteria E. coli criteria have been established in freshwater as follows for primary contact recreation (PCR), secondary contact recreation (SCR) 1 and 2, and noncontact recreation (NCR).

E. Coli Criteria for Freshwater Geometric Mean Single Sample Use (colonies/100 ml) (colonies/100 ml) PCR 126 399 SCR 1 630 ― SCR 2 1,030 ― NCR 2,060 ―

Enterococci criteria have been established in saltwater as shown in the following table.

Enterococci Criteria for Saltwater Geometric Mean Single Sample Use (colonies/100 (colonies/100 ml) ml) PCR 35 104 SCR1 175 ― NCR 350 ―

Assigning Recreational Uses Assigning recreational uses to classified and unclassified water bodies is defined in § 307.4(j) of the Texas Surface Water Quality Standards. The following tables provide a summary of how (1) presumed and designated uses are assigned and applied; (2) how uses less stringent that presumed or designated uses are assigned; and (3) when site-specific information or a RUAA is required.

Summary of assigning recreational uses to classified water bodies

Use Assigning uses RUAA Rule Change Required Required PCR Designated use unless otherwise No No specified in Appendix A of § 307.10 SCR1 Standards change is required Yes Yes SCR2 Standards change is required Yes Yes NCR Standards change is required Yes Yes

Summary of assigning recreational uses to unclassified water bodies

Use Assigning uses RUAA Rule Change Required Required PCR Presumed use if greater than or No No equal to 0.5 meter average depth or substantial pools with depths of one meter or greater SCR1 Presumed use if less than 0.5 meter No. Only a No. Public average depth, no substantial pools reasonable notification greater than 1 meter, and no level of will be existing PCR activities inquiry provided (equivalent through a to a Basic regulatory RUAA) is action and required. the assigned use will be subject to public comment and EPA approval. If presumed use is PCR, then a Yes Yes standards change is required

SCR2 Standards change is required Yes Yes NCR Standards change is required Yes Yes

Wastewater Permitting Wastewater discharge permits for Publically Owned Treatment Works (POTWs) will include effluent limits and monitoring requirements in accordance with 30 TAC § 309.3(h). Effluent limits and monitoring requirements for bacteria associated with industrial discharges will be evaluated on a case-by-case basis in order to meet instream water quality standards. Any rules that are approved in the future regarding bacteria limits in wastewater permits will supersede the provisions in this section.

Freshwater―E. coli is the indicator bacteria in effluent limits for wastewater discharges into freshwater. This includes those freshwaters that are identified in Appendix A of the water quality standards as high saline inland water bodies.

Saltwater―Enterococci is used as the indicator bacteria in effluent limits for wastewater discharges into saltwater.

Nutrients Introduction The TCEQ has included numerical criteria for nutrients in major reservoirs in the Standards. The criteria are based on historical chlorophyll a data from the main body of selected reservoirs. The TCEQ plans to develop nutrient criteria for streams and rivers, estuaries, and wetlands and evaluate them for inclusion in a future Standards revision.

In addition to numerical criteria for reservoirs, the following rules also address the issue of controlling nutrients in wastewater discharges:

• • General narrative criteria for nutrients in the Standards (§ 307.4) • Antidegradation provisions of the Standards (§ 307.5) • Watershed rules (30 TAC Chapter 311) • Edwards Aquifer rules (30 TAC Chapter 213)

General Screening Approach for Nutrient Impacts

Applicability The TCEQ evaluates applications for new or expanding domestic discharges to reservoirs, streams, and rivers to determine if an effluent limit is needed for total phosphorus (TP) or, in appropriate situations, total nitrogen (TN) to prevent violation of numerical nutrient criteria and/or preclude excessive growth of aquatic vegetation. Permit renewals and industrial discharges may be evaluated for potentially significant concentrations of TP (and if appropriate, TN) on a case-by-case basis.

The nutrient screening procedures in this section constitute the basis for the antidegradation review(s) for nutrients (see the chapter of this document entitled “Antidegradation” on page 55.) Additional factors for the antidegradation review(s) can be considered as appropriate to further address potential nutrient impacts of concern to sensitive water bodies.

General Procedure The following general procedure is also shown by flow chart in Figure 1 on page 28. Discharges >0.25 MGD into or near a reservoir that has been assigned numerical nutrient criteria in the Standards are first screened to evaluate main pool effects. Additional screening is performed regardless of flow size to evaluate local effects in the reservoir and in the tributary stream or river under the narrative provisions of the Standards.

Discharges into or near a reservoir that has not been assigned numerical nutrient criteria in the Standards are screened to evaluate local effects in the reservoir and in the tributary stream or river under the narrative provisions of the Standards.

Discharges into a stream or river but outside the distance of concern to a reservoir are screened to evaluate local effects in the stream or river.

Assessing Numerical Nutrient Criteria―Main Pool Effects For discharges >0.25 MGD to reservoirs that have numerical nutrient criteria, a detailed evaluation is performed using a completely-mixed, steady-state reservoir model to assess the effect of a proposed discharge on phosphorus levels in the main pool of the reservoir. Additionally, the effect of the TP change on chlorophyll a in the reservoir is estimated. Screening procedures are provided to evaluate model results and to determine if an effluent limit on TP is needed. The procedures for this evaluation are in the section entitled “Nutrient Screening for Main Pool Effects in Reservoirs with Numerical Nutrient Criteria” on page 30.

Assessing Narrative Nutrient Provisions―Local Effects To assess the local effects of discharges under the narrative nutrient provisions of the Standards, the TCEQ evaluates site-specific screening factors to assess eutrophication potential rated in terms of low, moderate, or high. Qualitative and quantitative guidelines are provided; screening factors may have one or the other or both. In some situations, only some of the suggested factors may be needed for the evaluation; and sufficient data may not always be available to address every factor. The procedures for this evaluation are in the sections entitled “Nutrient Screening for Local Effects in Reservoirs” on page 38 and “Nutrient Screening in Streams and Rivers” on page 44.

The individual screening factors establish the basis for an overall “weight- of-evidence” assessment to identify the need for a nutrient effluent limit. An effluent limit for TP is typically indicated when a significant number of screening factors are rated as moderate and high. However, the importance and weight of individual screening factors can vary from one site to another. If an effluent limit for TP is indicated, then screening factors and levels of concern can also be considered in determining the specific concentration limit for TP. Initial assessments can be improved and reconsidered in light of additional site-specific data and/or more extensive models and evaluations.

Nutrient Screening Procedure

Perform nutrient Does the screening for main pool discharge enter effects in the reservoir YES a reservoir that for discharges >0.25 has numeric MGD. Procedure starts nutrient on page 31. criteria?

NO ALSO

Does the discharge enter a Perform nutrient YES screening for local reservoir that does not have effects in the reservoir. numeric nutrient Procedure starts on criteria? page 29.

ALSO NO Perform nutrient screening for local effects in the river or stream. Procedure starts on page 46.

Figure 1. Flow chart showing the nutrient screening procedure.

Effluent Limits for Total Phosphorus When screening indicates that a reduction of effluent TP is needed, an effluent limit is recommended based on reasonably achievable technology- based limits, with consideration of the sensitivity of the site. Typical effluent limits for TP, as a daily average concentration, generally fall into the following ranges:

Permitted Flow (MGD) Typical TP Limit (mg/L) < 0.5 1.0 0.5 – 3.0 1.0 to 0.5 > 3.0 0.5

Higher or lower limits may be recommended based on site-specific mitigating factors.

Regulatory Factors that Prescribe Nutrient Controls in Discharge Permits Additional screening is unnecessary when the following site-specific regulatory factors explicitly establish an effluent limit for TP or other requirements:

• • A TP limit, or a prohibition on wastewater discharges, is established in a watershed rule (30 TAC Chapter 311) or in the Edwards Aquifer rules (30 TAC Chapter 213).
• • A water body is listed as impaired in the current Texas § 303(d) List due to excessive nutrients such as TP and potential nutrient additions are evaluated using the provisions in the section of this document entitled “Protecting Impaired Water Under Tier 1” (see page 57).
• • A TMDL or TMDL Implementation Plan specifies TP limits for wastewater discharges.

Focus on Phosphorus Instead of Nitrogen Considerations for nutrient impacts focus on TP rather than nitrogen for the following reasons:

• • substantially less data on total nitrogen have been collected in Texas reservoirs, streams, and rivers.
• • phosphorus is a primary nutrient in freshwaters, although nitrogen can be limiting during parts of the year.

• • nitrogen can be fixed directly from the atmosphere by most of the noxious forms of blue-green algae.
• • available waste treatment technologies make reducing phosphorus more effective than reducing nitrogen as a means of limiting algal production.

Effluent limits for total nitrogen can be considered in certain situations when existing or projected nitrogen levels would result in:

• • growth of nuisance aquatic vegetation.
• • a substantial increase in nitrate-nitrogen that could adversely affect public drinking water supplies (with a nitrate-nitrogen criterion of 10 mg/L).
• • potential eutrophication of unusually sensitive tidal waters, such as around seagrass beds.

Nutrient Screening for Main Pool Effects in Reservoirs with Numerical Nutrient Criteria

General Approach Numerical nutrient criteria in the Standards are expressed as the long-term average concentration of chlorophyll a in the main pool of a reservoir. These criteria are based on historical data to ensure that existing reservoir water quality is maintained.

Domestic wastewater discharges >0.25 MGD (and in some cases industrial wastewater discharges) into the watersheds of reservoirs with numerical nutrient criteria are evaluated to ensure that potential increases in nutrients and chlorophyll a in the main pool are relatively small and that water quality standards will be attained.

Applicability Evaluations are conducted for permit applications that propose to increase permitted discharge flow into the watersheds of reservoirs with numerical nutrient criteria. Evaluations are conducted for the following permitted discharge sizes within the listed distance from the normal pool elevation of the reservoir:

Permitted flow Distance from reservoir (MGD) (stream miles) >0.25 – < 1 ≤ 5 1–3 ≤ 10 >3 ≤ 20* * Very large discharges at greater distances may be evaluated.

Screening Model for TP The first screening is based on the relative change in TP concentration in the main pool of the reservoir that would occur solely from the proposed discharge. (The screening could also be applied to TN.) The change in TP is estimated by applying a steady-state, completely-mixed model to the reservoir using long-term estimates of reservoir retention time and reservoir volume at the normal operating pool elevation. The equations used in the following screening procedure represent one example of an appropriate steady-state model. 3

The TCEQ will consider more sophisticated models if they are submitted for review. If a more sophisticated model is used, predicted changes in chlorophyll a may be evaluated directly rather than evaluating predicted changes in TP.

The screening procedure comprises six steps as follows. An example is provided on page 34.

(1) For discharges that are over one mile from the normal operating pool elevation of the reservoir, estimate the loss of TP in the tributary stream or river as follows: {  k p [ x /(11318 QT0.5 )]} Equation 1: fTP , x  e

3 For a discussion of model formulations and settling velocity, see Kenneth Reckow. 1979. Empirical Lake Models for Phosphorus: Development, Applications, Limitations and Uncertainty. In: Perspectives in Lake Ecosystem Modeling. Donald Scavia and Andrew Robertson (eds.). Ann Arbor Science.

where: fTP,x = fraction of TP remaining at a distance x downstream of the discharge kP = TP decay rate at an assumed annual mean temperature of 20ºC. Assume to be 0.14/day unless an alternative rate is shown to be more appropriate. x = distance along the stream to the normal pool elevation of the reservoir (m) 11318 = Combination of default velocity coefficient of 0.131 (1/m·s)1/2 and conversion factor of 86,400 s/day (s1/2/(m1/2·day)) QT = permitted discharge flow plus harmonic mean flow upstream of the discharge (m3/s)

For discharge points that are less than or equal to one mile from the normal operating pool elevation of the reservoir, assume no loss of TP in the tributary stream or river (that is, set fTP,x = 1).

(2) Estimate the concentration of TP that is delivered to the reservoir from the discharge using Equation 2:

Equation 2: TPd  f TP , x  TPe

where: TPd = concentration of TP delivered to the reservoir from the discharge (mg/L) fTP,x = fraction of TP remaining at a distance x downstream of the discharge, calculated using Equation 1 TPe = concentration of TP in the effluent (mg/L), assumed to be 3.5 mg/L if no effluent data are available.

(3) Estimate the annual average loading of TP in the entire reservoir due to the discharge using Equation 3:

Equation 3: TPL  1,381,525  Q P  TPd

where: TPL = annual average loading of TP in the entire reservoir due to the discharge (g/yr) QP = permitted discharge flow (MGD) TPd = concentration of TP from the discharge delivered to the reservoir (mg/L), calculated using Equation 2

(4) Estimate the areal loading rate to the reservoir using Equation 4:

Equation 4: TPL w'  4,047  AR

where: w' = TP areal loading rate (g/m2·yr) TPL = annual average loading of TP in the entire reservoir due to the discharge (g/yr), calculated using Equation 3 AR = surface area of reservoir (acres) from Table F-2 in Appendix F

(5) Estimate the annual average concentration of TP in the entire reservoir due to the discharge using Equation 5: w' Equation 5: TPR  v s  0.3048 z / 

where: TPR = annual average TP in the entire reservoir due to the discharge (mg/L) w' = TP areal loading rate (g/m2·yr), calculated using Equation 4 vs = settling velocity (m/yr). For TP, assume 13 m/yr mean depth (ft), see Appendix F, Table F-2 (divide volume z= by surface area to get mean depth) τ = retention time (yrs), see Appendix F, Table F-2

(6) Finally, compare the change in TP in the main body of the reservoir to the reservoir’s mean TP concentration using Equation 6:

Equation 6: 100  TPR % change  TPA where: % change = percent change in TP relative to the mean TP of the reservoir TPR = annual average TP in the entire reservoir due to the discharge (mg/L), calculated using Equation 5 TPA = mean TP concentration of the reservoir (see Appendix F, Table F-1; these are long-term means of TP in the main pool of each reservoir)

Assessing the Results of Main Pool Screening If TP is estimated to change by 10% or less, a TP limit is not needed and chlorophyll a screening is not performed. If TP is estimated to change by more than 10 percent, then a TP limit or monitoring may be needed, depending on the results of the chlorophyll a screening (see next section).

Example Calculation: An applicant proposes to locate a new 2.0 MGD discharge on South Yegua Creek 3 miles upstream of Somerville Lake, Seg. 1212. Would chlorophyll a screening be performed, based on the estimated change in TP?

(1) Estimate the fraction of TP from the discharge that reaches Somerville Lake using Equation 1. Assume South Yegua Creek is intermittent with perennial pools with a harmonic mean flow of 0.1 cfs. Watch out for unit conversions!

0. 5 f TP , x  e{0.14[ 4827 /(11318( 0.08764 0.00283) )]}  0.82

(2) Estimate the concentration of TP from the discharge that reaches Somerville Lake using Equation 2. Assume an effluent TP concentration of 3.5 mg/L.

TPd  0.82  3.5  2.87 mg/L

(3) Estimate the annual average loading of TP from the discharge to Somerville Lake in its entirety using Equation 3.

TPL  1,381,525  2.0  2.87  7,929,482 g/yr

(4) Estimate the areal loading rate from the discharge to Somerville Lake using Equation 4. (Reservoir characteristics are in Table F-2 in App. F.)

7,929,482 w'   0.17 g/m2·yr 4,047  11,555

(5) Estimate the annual average TP concentration from the discharge in Somerville Lake using Equation 5. 0.17 TPR   0.0090 mg/L 13  0.3048  (147,104 / 11,555) / 0.65

(6) Compare the change in TP due to the discharge to the mean TP concentration in Somerville Lake using Equation 6.

100  0.009 % change   10.9 % 0.082

Chlorophyll a screening is necessary based on the TP screening. This example is continued with chlorophyll a calculations on page 30, local effects screening for Somerville Lake on page 35, and local effects screening for South Yegua Creek on page 42.

Estimating Change in Chlorophyll a If the projected change in TP over the entire reservoir is greater than 10%, the relative potential increase in chlorophyll a that may result from the estimated increase in TP is approximated. This evaluation is approximate because of the high variability in the relationship of TP to chlorophyll a. However, the evaluation provides additional information on the need for a TP limit or monitoring.

The potential increase in chlorophyll a can be estimated from the projected increase in TP by the following regression equation 4 for Texas reservoirs, as shown in Figure 2 and Equation 7 below:

Equation 7: ln(Chl a, μg/L) = 0.9312 ln(TP, mg/L) + 5.14

4.5 4.0 3.5 LN(Chl a, ug/L)

3.0 2.5 2.0 1.5 1.0 y = 0.9312x + 5.1400 0.5 R2 = 0.4679 0.0 -5.0 -4.0 -3.0 -2.0 -1.0 Ln(TP, mg/L)

Figure 2. Relationship of mean chlorophyll a concentration to mean total phosphorous concentration in reservoirs.

The relationship of TP to chlorophyll a is statistically significant but highly variable from one reservoir to another and the regression may not accurately predict small changes in chlorophyll a assimilative capacity. Nevertheless, the screening is useful to ensure that criteria for chlorophyll a will be maintained. Alternative evaluations to predict the effect of phosphorus increases on chlorophyll a in specific reservoirs can also be considered.

4 The regression is based on the long-term means of TP and chlorophyll a for the individual reservoirs in Table F-1 of Appendix F, with selected outliers removed (as noted in a January 23, 2009 letter from Larry Hauck at the Texas Institute for Applied Environmental Research). The r-squared for the regression is 0.47.

For ease of calculation, Equation 7 can be expressed as follows: Equation 8: Chl a (μg/L) = 170.7 TP (mg/L)0.9312

The potential change in chlorophyll a in the entire reservoir is then evaluated using the following procedure.

(1) Use Equation 8 to calculate the reservoir chlorophyll a value that corresponds to the mean TP concentration in Table F-1 in Appendix F:

Equation 8a: ChlAP = 170.7 TPA0.9312

(2) Use Equation 8 to calculate the reservoir chlorophyll a value that corresponds to the sum of the mean TP concentration (from Table F-1) and the annual average TP in the entire reservoir due to the discharge (TPR, from Equation 5):

Equation 8b: ChlAR = 170.7 (TPA + TPR )0.9312

(3) Use Equation 9 to estimate the predicted change in chlorophyll a in the reservoir due to the discharge:

Equation 9: ChlR = ChlAR - ChlAP

where: ChlR = chlorophyll a added by the discharge (μg/L) ChlAR = chlorophyll a (μg/L) predicted in the reservoir due to the discharge at permitted flow, calculated using Equation 8a ChlAP = chlorophyll a (μg/L) predicted in the reservoir at ambient TP concentration (see Appendix F, Table F-1), calculated using Equation 8b

(4) Use Equation 10 to compare the predicted change in chlorophyll a in the reservoir (due to the discharge) to the assimilative capacity of the reservoir, which is estimated to be the chlorophyll a criterion minus the ambient chlorophyll a concentration:

100 [Chl R ] Equation 10: % change  ChlC  Chl A

where: % change = percent change in chlorophyll a relative to the assimilative capacity of the reservoir ChlR = annual average chlorophyll a in the entire reservoir due to the discharge (mg/L), calculated using Equation 9 ChlC = chlorophyll a criterion for the reservoir from Appendix F of the Standards.

ChlA = mean chlorophyll a concentration of the reservoir (see Appendix F, Table F-1; these are long-term means of chlorophyll a in the main pool of each reservoir)

If the projected decrease in the estimated assimilative capacity of chlorophyll a is >20%, then a limit for TP is indicated. If the projected decrease is 10-20%, then monitoring for TP is indicated. If the projected decrease is <10%, then neither a TP limit nor monitoring is indicated.

Determining the Appropriate TP Limit Use the typical effluent limit for TP based on permitted flow (see the table on page 29) in the screening procedure to estimate how much TP in the reservoir will change due to the discharge. The limit may need to be adjusted if the estimated change in reservoir TP is still >10% and the estimated change in chlorophyll a assimilative capacity is still >20%.

Example Calculation: This example is a continuation of the scenario presented on page 35. An applicant proposes to locate a new 2.0 MGD discharge on South Yegua Creek 3 miles upstream of Somerville Lake, Seg. 1212. Would a TP limit or monitoring likely be recommended to address main pool effects in Somerville Lake, based on the estimated change in chlorophyll a?

(1) Use Equation 8a to estimate the concentration of chlorophyll a in Somerville Lake based on the ambient TP concentration for Somerville Lake.

ChlAP = 170.7 TPA0.9312 = 170.7×0.0820.9312 = 16.6 μg/L

(2) Use Equation 8b to estimate the concentration of chlorophyll a in Somerville Lake based on the sum of the ambient TP concentration for Somerville Lake and the increase in TP concentration predicted by the previous screening calculations.

ChlAR = 170.7 (TPA + TPR )0.9312 = 170.7×(0.082+0.0090)0.9312 = 18.3 μg/L

(3) Use Equation 9 to estimate the change in chlorophyll a concentration in Somerville Lake Somerville Lake in its entirety.

ChlR = ChlAR - ChlAP = 18.3 μg/L – 16.6 μg/L = 1.7 μg/L

(4) Use Equation 10 to compare the estimated increase in chlorophyll a to the assimilative capacity of Somerville Lake.

100 [Chl R ] 100  [1 .7 g / L ] % change    13 .6% Chl C  Chl A [ 47 .64  35 .16 ]g / L

Nutrient Screening for Local Effects in Reservoirs

General Approach To assess local effects in reservoirs from a discharge under the narrative nutrient provisions of the Standards, the TCEQ first evaluates the discharge using the general guidelines in this section. If the general guidelines indicate that a TP limit should be considered, then the TCEQ conducts a more comprehensive review using site-specific screening factors. Eutrophication potential is rated as a low, moderate, or high level of concern for each factor. Some screening factors can be rated on either qualitative or quantitative information, depending on data availability. Not every factor is appropriate or definable at a particular site.

Applicability These screening procedures focus on larger reservoirs, such as those used for public water supplies. They can also be applied to smaller perennial impoundments (no smaller than about 10 surface acres in size), but some of the site-specific screening factors might not apply. Smaller impoundments, ponds, and perennial pools are addressed in the nutrient screening procedures for streams and rivers (see page 44). Evaluations are conducted for the following permitted discharge sizes within the listed distance from the normal pool elevation of the reservoir:

Permitted flow Evaluation Distance (MGD) (stream miles) < 0.25 <5 0.25 to < 1.0 < 10 ≥ 1.0* < 20 * Very large discharges may be evaluated on a case-by-case basis.

A separate analysis is conducted to compare the potential impact of the discharge with numerical criteria for nutrients in the main pool of the reservoir (see the previous section of this document entitled “Nutrient Screening for Main Pool Effects in Reservoirs with Numerical Nutrient Criteria” on page 30).

General Guidelines for Considering TP Limits TP limits are potentially indicated in the following situations:

• • for new or expanding discharges ≥ 1 MGD into or near reservoirs;
• • for new or expanding discharges ≥ 0.25 MGD into or near shallow, restricted coves of reservoirs; and

• • where explicitly required by watershed rules or other specific regulatory requirements.

Other situations where receiving streams appear to be especially sensitive to nutrient increases can also be considered. Smaller proposed discharges (such as those between 0.1 to 0.25 MGD) can also be of concern and will be evaluated for TP limits if the discharge location is into a sensitive area with very low dispersion.

Site-Specific Screening Factors For cases where the general guidelines indicate that a limit on TP should be considered further, site-specific screening factors are applied to assess the potential need for a TP limit to control eutrophication. These screening factors include the following:

A. size of discharge B. distance from reservoir C. sensitivity to nutrient enrichment―water clarity D. sensitivity to growth of aquatic vegetation―observations E. sensitivity to growth of aquatic vegetation―shading and sunlight in narrow backwaters and small coves F. consistency with similar permits I. local dispersion and mixing J. impact on the main pool of the reservoir K. existence of listed concern for nutrients or aquatic vegetation in the TCEQ’s integrated report (§ 305(b))

The level of concern (low, moderate, or high) for each of these factors is described in the following sections.

A. SIZE OF DISCHARGE The size of a discharge into or near a reservoir affects phosphorus loading and the concern for potential impacts, as indicated in the following table. A higher level of concern may be assigned to discharges into sensitive areas.

Level of Concern Permitted Flow (MGD) Low < 0.25 Moderate 0.25 to < 1.0 High ≥ 1.0

B. DISTANCE FROM RESERVOIR The level of concern is based on the size of the discharge and its distance from the normal operating pool of the reservoir.

Size of Level of Concern (stream miles) Discharge (MGD) Low Moderate High < 0.25 >3 3 to > 1 ≤1 0.25 to < 1.0 >7 7 to > 3 ≤3 ≥ 1.0* > 15 15 to > 7 ≤7 * Very large discharges may be evaluated on a case-by-case basis.

C. SENSITIVITY TO NUTRIENT ENRICHMENT – WATER CLARITY Reservoirs with higher transparency allow more light to penetrate, which increases the tendency for algal growth. In addition, the aesthetic impact of phytoplankton algal blooms tends to be greater in reservoirs that generally have low turbidity. A qualitative screening approach is used when other data are not readily available. A quantitative screening approach that uses mean secchi depth as a measure of water clarity may be used if adequate secchi data are available.

Option 1: Qualitative analysis: Relative clarity is assessed using general observations and knowledge by individuals who are familiar with the reservoir or similar reservoirs in the area.

Level of Discharge Environment Concern Low Turbid from suspended particles or color (tannins) Some visible turbidity but without heavy Moderate murkiness High A “clear water” reservoir with high transparency

Option 2: Quantitative analysis: Relative clarity is assessed using the mean of long-term secchi data (if available) in the main pool of the reservoir or at sampling sites near the proposed discharge. Levels of concern based on clarity are as follows:

Level of Concern Secchi (m)* Low ≤ 0.75 Moderate 0.76 to 1.27 High ≥ 1.28 *Secchi ranges for each impact level are derived by dividing the mean secchi values in Table F-1 of this document into thirds.

D. SENSITIVITY TO GROWTH OF AQUATIC VEGETATION―OBSERVATIONS When site-specific observations are available with respect to aquatic vegetation in areas of the water body with existing wastewater discharges, the applicable levels of concern are as follows:

Level of Observed Aquatic Vegetation Concern Little attached, floating, or suspended aquatic Low vegetation Limited patches of attached, floating, or suspended Moderate vegetation High Heavy patches of vegetation in areas with nutrient input

E. SENSITIVITY TO GROWTH OF AQUATIC VEGETATION―SHADING AND SUNLIGHT IN NARROW BACKWATERS AND SMALL COVES The sensitivity of narrow backwaters and small coves to various kinds of aquatic vegetation can be affected by the extent to which sunlight reaches the water’s surface. The amount of available sunlight is related to the amount of tree canopy cover during warm seasons.

Level of Canopy Cover and Shading During Warm Months Concern Low Extensive canopy cover shades most of water surface Substantial canopy cover, but shading is only partial and Moderate not equivalent to “deep woods” Canopy cover diffuses light to some extent, but High substantial light reaches water surface

F. CONSISTENCY WITH OTHER PERMITS An assessment is conducted to determine whether TP limits have been required for other wastewater permits with similar characteristics and locations in this area.

Level of TP Limits in Other Permits in the Area? Concern Low Similar permits usually do not have effluent limits for TP There are some similar permits with TP limits, but Moderate applicability is site-specific and not “across-the-board” Discharges with similar characteristics usually have a TP High limit

G. LOCAL DISPERSION AND MIXING The local impacts of a discharge to a reservoir depend greatly on the extent to which the discharge is dispersed and mixed at the discharge site. Both qualitative and quantitative options for this analysis are described below. The qualitative option is based on the general physical characteristics of the discharge site. The quantitative option uses either a completely-mixed model or a QUAL-TX stream model to determine the extent to which phosphorus concentrations are potentially elevated by the discharge (∆TP).

Option 1: Qualitative analysis: Discharges to the main body of the reservoir or to large, deep open coves are of low potential concern with respect to dispersion and mixing. Discharges into smaller coves, shallow areas, inundated creeks, and canals are of moderate concern. Discharges are of high concern into narrow, slow moving areas of a reservoir, whether riverine transition zones or wetlands.

Level of Concern Discharge Environment Low Large, open coves or main body of reservoirs Moderate Coves with restricted circulation High Narrow, backwater transition zones

Option 2: Quantitative analysis:

A: Discharges to the main body of the reservoir or to large deep open coves (relative to the size of the discharge) are assessed as having a low level of concern with respect to dispersion and mixing. For this scenario, the assessment is still qualitative, and no quantitative analysis is performed.

B: Discharges into coves with restricted circulation are evaluated to assess the projected increase in local TP concentration (∆TP) that will be added by the discharge at permitted flow. A steady-state, completely-mixed model is used to determine ∆TP as described in the section entitled “Nutrient Screening for Main Pool Effects in Reservoirs with Numerical Nutrient Criteria” on page 30.

Default cell size for the model is 10 acres, although smaller cell sizes may be used to address physical barriers at smaller distances. Surface area and average depth are determined from best available map information. Tributary inflows at 7Q2 are used in the calculation of detention time for the cell volume. (Note: if a completely-mixed, steady-state model for dissolved oxygen is also used at a site, the morphometry for the TP model will correspond to the DO model.)

C: Discharges into narrow, backwater transition zones that are within the normal operating pool of the reservoir are screened using the same QUAL-TX model that is used for dissolved oxygen (if available for that site). The QUAL-TX results are evaluated by assessing the instream proportion of effluent at a distance of 300 feet from the point where the discharge enters the transition zone within the normal operating pool.

The ∆TP is calculated by first either assuming an effluent concentration of 3.5 mg/L TP or by using effluent TP data (if available) and then multiplying the effluent TP by the instream proportion of effluent. For discharges that are greater than one stream mile from the normal operating pool, the loss of phosphorus over stream distance can be calculated as described in the section entitled “Nutrient Screening for Main Pool Effects in Reservoirs with Numerical Nutrient Criteria” on page 30.

For discharges to restricted coves and backwater transition zones (cases B and C above), levels of concern for the predicted ∆TP are as follows:

Level of Concern Predicted ∆TP (mg/L) Low < 0.05 Moderate 0.05 to < 0.25 High ≥ 0.25

H. IMPACT ON THE MAIN POOL OF THE RESERVOIR Although this screening factor is not a local effect, it is useful for evaluating discharge impacts to reservoirs with no numeric nutrient criteria when:

• • the reservoirs are larger than 100 surface acres; and
• • there are major discharges that are large enough to potentially cause a significant change to phosphorus concentrations in the main pool of the reservoir.

A steady-state, completely-mixed model is used to determine ∆TP in the main pool, as described in the section entitled “Nutrient Screening for Main Pool Effects in Reservoirs with Numerical Nutrient Criteria” on page 30. (Note that ∆TP is equal to TPR, which is calculated in step 5 of the screening procedure.) Using the results of that modeling procedure, the following levels of concern are assigned to various predicted changes in TP concentration:

Level of Concern Predicted ∆TP (mg/L) Low < 0.0001 Moderate 0.0001 to < 0.001 High ≥ 0.001

I. EXISTENCE OF LISTED CONCERN FOR NUTRIENTS OR AQUATIC VEGETATION IN THE TCEQ’S INTEGRATED REPORT (§ 305(B)) The latest TCEQ § 305(b) report (integrated report) is reviewed to see if the water body is listed as a concern for nutrients or aquatic vegetation.

Listed as a Concern for Nutrients or Aquatic Level of Concern Vegetation in Integrated Report? No concern for nutrients or aquatic vegetation in Low latest integrated report. Concern for nutrients or aquatic vegetation in latest Moderate integrated report due to exceedance of the 85th percentile. Concern for nutrients or aquatic vegetation in latest High integrated report due to documented problem with one or both of these.

Assessing the Results of Site-Specific Screening Factors Once the individual screening factors have been rated, they provide the basis for a “weight-of-evidence” assessment to identify the need for a nutrient effluent limit. An effluent limit for TP is probably needed when a substantial number of screening factors are rated moderate and high. If the overall assessment determines that the discharge is at a moderate level of concern, a limit might be indicated if one or more of the factors are particularly elevated. A monitoring requirement may be appropriate if a TP effluent limit is not required.

Alternatively, numeric values can be assigned to each level of concern (for example, Low=1, Moderate=3, High=5) and the values averaged. If the average is <2, a TP limit is probably not needed. If the average is > 4, a TP limit is probably needed. If the average is 2-4, either TP monitoring or a TP limit is possible depending on the specifics of the case. Note that the importance and weight of the individual screening factors can vary from one site to another.

If an effluent limit for TP is indicated, the screening factors and levels of concern are used to help determine the specific effluent limit for TP. Initial assessments can be improved and reconsidered in light of additional site-specific data and more extensive models and evaluations.

Example of local effects screening for a reservoir: This example is a continuation of the scenario presented on page 25. An applicant proposes to locate a new 2.0 MGD discharge 3 miles upstream of Somerville Lake, Segment 1212, on South Yegua Creek. Would a TP limit likely be needed to address local effects in Somerville Lake?

A. Size of discharge: 2.0 MGD – high B. Distance from reservoir: 3 miles – high

C. Sensitivity to nutrient enrichment – water clarity: Option 1, qualitative analysis: Information unavailable Option 2, quantitative analysis: Mean secchi (see Table F-1) = 0.68 m – low

D. Sensitivity to growth of aquatic vegetation – observations: Small patches of floating algae mats were found along the shoreline and in the cove where South Yegua Creek enters Somerville Lake - moderate

E. Sensitivity to growth of aquatic vegetation – shading and sunlight in narrow backwaters and small coves: Based on aerial photos from August 2004, the backwater of South Yegua Creek has minimal canopy cover – high

F. Consistency with other permits: No other permits that discharge to Somerville Lake have TP limits – low

G. Local dispersion and mixing: Option 1, qualitative analysis: Narrow, backwater transition zone – high Option 2, quantitative analysis, case C: Model analysis not performed at this time.

H. Impact on main pool of the reservoir: N/A - evaluated separately using screening for reservoirs with numerical criteria.

I. Existence of concern for nutrients or aquatic vegetation on the 305(b) list: The South Yegua Creek arm of Somerville Lake is not listed in the 2008 305(b) report as a concern for water quality based on screening levels of nutrients or aquatic vegetation - low

Final assessment: The screening values ranked as low (4), moderate (1), and high (4), so the overall ranking is moderate (mean = 3.0). TP monitoring is already being included in the permit based on the previous screening for the entire reservoir. Based on the local effects screening, no additional limitations on TP would likely be recommended.

Nutrient Screening for Streams and Rivers

General Approach To assess local effects in streams and rivers from discharges under the narrative nutrient provisions of the Standards, the TCEQ first evaluates the discharge using the general guidelines. If the general guidelines in this section indicate that a TP limit should be considered, then the TCEQ conducts a more comprehensive review using site-specific screening factors. Eutrophication potential is rated as a low, moderate, or high level of concern for each factor. Some screening factors can be rated on either qualitative or quantitative information, depending on data availability. Not every factor is always appropriate or definable at a particular site.

Applicability These screening procedures are primarily intended for freshwater streams and rivers. Perennial impoundments greater than 10 surface acres along streams can be individually evaluated using screening factors for reservoirs, as described in previous sections.

If a stream or river changes characteristics downstream of the discharge such that eutrophication impacts might be greater in downstream areas, then screening procedures are also applicable to those downstream reaches. As a rough guide, nutrient screening procedures are typically applied for the following permitted discharge sizes within the following distance of the discharge point:

Permitted flow Evaluation Distance (MGD) (stream miles) < 0.25 <3 0.25 to < 1.0 <7 ≥ 1.0* < 15 * Very large discharges may be evaluated on a case-by-case basis.

General Guidelines for Assigning TP Limits TP limits are potentially indicated in the following situations:

• • for new or expanding discharges with permitted flow ≥ 0.25 MGD to perennial, shallow, relatively clear streams with rocky bottoms or other substrates that promote the growth of attached vegetation;
• • for new or expanding discharges with permitted flow ≥ 0.25 MGD to streams with long, shallow, relatively clear perennial impoundments; and

• • where explicitly required by watershed rules or other specific regulatory requirements.

Other situations where receiving streams appear to be especially sensitive to nutrient increases can also be considered. Smaller proposed discharges (such as those between 0.1 to 0.25 MGD) can also be of concern and will be evaluated for TP limits if the discharge location is into a sensitive area with very low dispersion/dilution.

Site-Specific Screening Factors For cases where a limit on TP should be considered further, site-specific screening factors are applied to assess the potential need for a TP limit to control instream vegetation growth. These screening factors include the following:

A. size of discharge B. instream dilution C. sensitivity to growth of attached algae―type of bottom D. sensitivity to growth of attached vegetation―depth E. sensitivity to nutrient enrichment―water clarity F. sensitivity to growth of aquatic vegetation―observations G. sensitivity to growth of aquatic vegetation―shading and sunlight H. streamflow sustainability I. impoundments and pools J. consistency with other permits K. existence of listed concern for nutrients or aquatic vegetation in the TCEQ’s integrated report (§ 305(b))

The level of concern (low, moderate, or high) for each of these factors is described in the following sections. Calculations are based on 7Q2 stream flows unless otherwise indicated.

A. SIZE OF DISCHARGE The permitted size of the discharge affects the downstream extent of impact and the amount of nutrient loading to deeper, slower moving areas such as pools and small impoundments.

Level of Concern Permitted Flow (MGD) Low < 0.25 Moderate 0.25 to < 1.0 High ≥ 1.0

B. INSTREAM DILUTION The potential impact of nutrients from discharges to streams and rivers is substantially affected by the dilution and resulting instream concentration during dry-weather flows. The percent effluent instream at the discharge and at downstream points is calculated at permitted discharge flow and 7Q2 streamflow.

Level of Concern Percent Effluent Low < 10 Moderate 10 to < 25 High ≥ 25

The percent of effluent instream can be obtained either from the effluent percentages calculated for critical conditions or from modeling results for dissolved oxygen.

C. SENSITIVITY TO GROWTH OF ATTACHED ALGAE – TYPE OF BOTTOM In shallow, clear streams, the tendency for the stream to have nuisance levels of attached algae depends in part upon a stable stream bottom upon which attached algae may grow.

Level of Concern Bottom Substrate Low Mud or sand Moderate Rocky cobble, gravel, usually with riffle areas High Larger rocks and boulders, rock slabs

D. SENSITIVITY TO GROWTH OF ATTACHED VEGETATION – DEPTH The growth of attached vegetation tends to be facilitated by the extent of shallow areas. Levels of concern associated with the potential for eutrophication are as follows:

Level of Depth Characteristics Concern Low Relatively steep banks and deep channels across stream Moderate Gently sloping sides with some shallow areas Substantial shallow areas near banks and in stream High channel

E. SENSITIVITY TO NUTRIENT ENRICHMENT―WATER CLARITY Relative clarity is assessed using general observations and knowledge by individuals who are familiar with the stream or river.

Level of Concern Discharge Environment Turbid from suspended particles or color Low (tannins), bottom may not be visible Some visible turbidity but without heavy Moderate murkiness, bottom sometimes visible High Relatively clear water, bottom usually visible

F. SENSITIVITY TO GROWTH OF AQUATIC VEGETATION―OBSERVATIONS When site-specific observations are available with respect to aquatic vegetation in areas of the water body with existing wastewater discharges, the levels of concern for nutrient impacts are as follows:

Level of Observed Aquatic Vegetation Concern Little attached, floating, or suspended aquatic Low vegetation Limited patches of attached, floating, or suspended Moderate vegetation Heavy patches of vegetation in areas with nutrient High input

G. SENSITIVITY TO GROWTH OF AQUATIC VEGETATION―SHADING AND SUNLIGHT The sensitivity of streams to various kinds of aquatic vegetation can be affected by the extent to which sunlight can reach the water’s surface. The amount of available sunlight is related to the amount of tree canopy cover during warm seasons.

Level of Canopy Cover and Shading During Warm Months Concern Low Extensive canopy cover shades most of stream surface Substantial canopy cover, but shading is only partial Moderate and not equivalent to “deep woods” Canopy cover diffuses light to some extent, but High substantial light reaches stream surface

H. STREAMFLOW SUSTAINABILITY Growth of aquatic vegetation and the potential impact of nutrients are enhanced by flow characteristics that sustain permanent aquatic environments.

Level of Concern Stream Type Low Intermittent Moderate Intermittent with perennial pools High Perennial

I. IMPOUNDMENTS AND POOLS Perennial impoundments that are greater than 10 surface acres can be individually evaluated with screening factors that are applied to reservoirs (see previous section that starts on page 38). The presence of smaller riverine impoundments and perennial pools can also increase the level of concern for eutrophication impacts.

Level of Concern Extent of Pools and Impoundments No impoundments > 300 feet in length and no Low reach with extensive smaller pools No impoundments > 300 feet in length, but Moderate substantial smaller pools over > 20% of affected reach High At least one impoundment > 300 feet in length

J. CONSISTENCY WITH OTHER PERMITS An assessment is conducted to determine whether TP limits have been required for other wastewater permits with similar characteristics and locations in this area.

Level of TP Limits in Other Permits in the Area? Concern Similar permits usually do not have effluent limits for Low TP There are some similar permits with TP limits, but Moderate applicability is site-specific and not “across-the-board” Discharges with similar characteristics usually have a High TP limit

K. EXISTENCE OF LISTED CONCERN FOR NUTRIENTS OR AQUATIC VEGETATION IN THE TCEQ’S INTEGRATED REPORT (§ 305(B)) The latest TCEQ § 305(b) report (“integrated report”) is reviewed to see if the water body is listed as a concern for nutrients or aquatic vegetation.

Listed as a Concern for Nutrients or Aquatic Level of Concern Vegetation in Integrated Report? No concern for nutrients or aquatic vegetation in Low latest integrated report. Concern for nutrients or aquatic vegetation in latest Moderate integrated report due to exceedance of the 85th percentile. Concern for nutrients or aquatic vegetation in latest High integrated report due to documented problem with one or both of these.

Assessing the Results of Site-Specific Screening Factors Once the individual screening factors have been rated, they provide the basis for a “weight-of-evidence” assessment to identify the need for a nutrient effluent limit. An effluent limit for TP is probably needed when a substantial number of screening factors are rated moderate and high. If the overall assessment determines that the discharge is at a moderate level of concern, a limit might be indicated if one or more of the factors was particularly elevated. A monitoring requirement may be appropriate if a TP effluent limit is not required.

Alternatively, numeric values can be assigned to each level of concern (for example, Low=1, Moderate=3, High=5) and the values averaged. If the average is <2, a TP limit is probably not needed. If the average is > 4, a TP limit is probably needed. If the average is 2-4, either TP monitoring or a TP limit is possible, depending on the specifics of the case. Note that the importance and weight of the individual screening factors can vary from one site to another.

If an effluent limit for TP is indicated, the screening factors and levels of concern are used to help determine the specific effluent limit for TP. Initial assessments can be improved and reconsidered in light of additional site-specific data, more extensive models, and evaluations.

Nutrient Screening for Estuaries Limits for total phosphorus are generally not considered for discharges to tidal rivers or estuaries because vegetation growth in tidal waters is typically controlled by nitrogen rather than by phosphorus. At sensitive sites such as those with seagrasses nearby, limits on nutrients are considered for new or increased discharges.

Other Applicable Rules In addition to effluent limits based on dissolved oxygen, bacteria, nutrients, and other appropriate criteria, the draft permit also includes all treatment requirements of applicable rules such as:

• • 30 TAC Chapter 309—“Domestic Wastewater Effluent Limitation and Plant Siting” • 30 TAC Chapter 311—“Watershed Protection” • 30 TAC Chapter 213—“Edwards Aquifer” • 30 TAC Chapter 319—“General Regulations Incorporated Into Permits.”

These rules are available on the agency’s Web site (www.tceq.state.tx.us); follow the link for “Rules.”

Example of local effects screening for a river: This example is a continuation of the scenario presented on page 25. An applicant proposes to locate a new 2.0 MGD discharge 3 miles upstream of Somerville Lake, Segment 1212, on South Yegua Creek. Assume South Yegua Creek is intermittent with perennial pools. Would a TP limit likely be needed to address local effects in the creek?

A. Size of discharge: 2.0 MGD – high

B. Instream dilution: South Yegua Creek is intermittent with perennial pools, so the percent effluent is 100% - high

C. Sensitivity to growth of attached algae – type of bottom: Mud or sand - low

D. Sensitivity to growth of attached vegetation – depth: The banks of South Yegua Creek are not steep in most areas; some shallow areas are present - moderate

E. Sensitivity to nutrient enrichment – water clarity: The water is brown in color and highly turbid, and the stream bottom is not visible - low

F. Sensitivity to growth of aquatic vegetation – observations: Patches of attached aquatic vegetation are growing in the shallow pool areas; however, such vegetation is absent in the deeper pool areas - moderate

G. Sensitivity to growth of aquatic vegetation – shading and sunlight: Based on aerial photos from August 2004, South Yegua Creek has minimal canopy cover - high

H. Streamflow sustainability: South Yegua Creek is intermittent with perennial pools - moderate

I. Impoundments and pools: South Yegua Creek is intermittent with perennial pools - moderate

J. Consistency with other permits: No other permits that discharge to tributaries of Segment 1212 have TP limits - low

K. Existence of concern for nutrients or aquatic vegetation on the 305(b) list: South Yegua Creek is not listed in the 2008 305(b) report as a concern for water quality based on screening levels of nutrients or aquatic vegetation - low

Final Assessment: The screening values ranked as low (4), moderate (4), and high (3), so the overall ranking is on the low side of moderate (mean = 2.8). TP monitoring is already being included in the permit based on the previous screening for the entire reservoir. Based on the local effects screening for South Yegua Creek, no additional limitations on TP would likely be recommended.

Antidegradation

Policy The antidegradation policy and framework for the antidegradation implementation procedures are specified in section § 307.5 of the Standards. This chapter provides additional guidance for antidegradation implementation. The antidegradation policy affords three tiers of protection to the water in the state.

• • The first level (Tier 1) stipulates that existing uses and water quality sufficient to protect existing uses will be maintained.
• • The second level (Tier 2) stipulates that activities subject to regulatory action will not be allowed if they would cause degradation of waters that exceed fishable/swimmable quality. Exceptions to this stipulation can be made if it can be shown to the TCEQ’s satisfaction that the lowering of water quality is necessary for important economic or social development.
• • The third level (Tier 3) stipulates that the quality of outstanding national resource waters will be maintained and protected.

General Applicability The antidegradation policy applies to actions regulated under state and federal authority that would increase pollution of water in the state. The antidegradation implementation procedures in this document apply to any increase in pollution authorized by TPDES wastewater discharge permits or by other state and federal permitting and regulatory activities.

Increases in pollution are determined by: (1) information on effluent characteristics that are provided in the application for the TPDES permit, the draft permit, and/or in other available sources; and (2) final effluent limits for flow, loading, and concentration in the previous permit compared with the proposed permit. Permits that are consistent with an approved WLE or TMDL under the antidegradation policy do not receive a separate antidegradation review for the applicable parameters unless the discharge may cause impacts on the receiving water that were not addressed by the WLE or TMDL.

Tier 1—Protecting Uses Antidegradation reviews under Tier 1 ensure that existing water quality uses are not impaired by increases in pollution loading. Numerical and narrative criteria necessary to protect existing uses will be maintained. TPDES permit amendments or new permits that allow increased pollution loading are subject to review under Tier 1 of the antidegradation policy, and all pollution that could cause an impairment of existing uses is included in the evaluation.

Existing uses and criteria for unclassified waters are established as discussed in the section in this document entitled “Assigned Aquatic Life Uses” on page 16. Applicable uses, and the numerical and narrative criteria needed to support those uses, are established in the Standards. Uses that may be applicable to individual water bodies include:

• • aquatic life categories • primary and secondary contact recreation and noncontact recreation • sustainable and incidental fisheries • public drinking water supply • aquifer protection • oyster waters.

Additional uses may be applicable such as:

• • navigation • agricultural water supply • industrial water supply • seagrass propagation • wetland water quality functions.

Numerical criteria may be applicable to individual water bodies:

• • dissolved oxygen • total dissolved solids • sulfate • chloride • pH • temperature • bacterial indicators of recreational suitability • nutrient indicators (chlorophyll a) • toxic pollutants to protect aquatic life and human health.

Narrative criteria may be applicable to individual water bodies for:

• • radioactive materials • nutrients (phosphorus, nitrogen) • temperature • salinity

• • dissolved oxygen necessary to protect aquatic life • habitat necessary to protect aquatic life • aquatic recreation • toxic pollutants to protect aquatic life, human health, terrestrial wildlife, livestock, and domestic animals.

Narrative criteria may also apply for aesthetic parameters such as:

• • taste and odor • suspended solids • turbidity • foam and froth • oil and grease.

The review of water quality impacts from a proposed permit action is conducted in accordance with the procedures established in other chapters of this document including “Determining Water Quality Uses and Criteria” on page 14, “Evaluating Impacts on Water Quality” on page 20, and “Toxic Pollutants” on page 130.

Protecting Impaired Waters under Tier 1 The procedures in this section address proposed wastewater discharges to water bodies listed on the Clean Water Act § 303(d) List as not meeting instream water quality standards. The procedures are intended to assist in establishing permit requirements until a TMDL is completed. Provisions in 40 CFR Parts 122, 123, 124, and 131 are also applicable.

Definitions Listed water body refers to a portion of a water body that does not meet water quality standards and is listed in the current § 303(d) List. This portion of a water body is called an assessment unit (AU), and it is the smallest geographic area of a water body that is assessed.

Listed pollutant refers to a pollutant or pollutants that cause the failure of a listed water body to attain water quality standards. For a listing due to a failure to attain dissolved oxygen criteria, the pollutants of concern include oxygen-demanding organic substances and ammonia-nitrogen.

An existing or proposed discharge is considered to be a discharge to a listed water body if (1) the discharge is directly to a listed water body, or (2) the discharge is in close enough proximity to potentially impact the listed area.

General Provisions Permits for discharges to listed water bodies will not allow:

• • an increase in the loading of a listed pollutant that will cause or contribute to the violation of water quality standards; and
• • other conditions that will cause or contribute to the violation of water quality standards.

Subsequent references to increased loadings of listed pollutants will also include consideration of other conditions that will cause or contribute to the violation of water quality standards.

Permit applications are reviewed by the TCEQ to identify discharges into the watersheds of listed AUs.

Applicability to Specific Parameters

Substances that Deplete Instream Dissolved Oxygen Effluent limits will be established to avoid an increase in BOD loading (carbonaceous or nitrogenous) unless it is demonstrated that: (1) water quality standards for dissolved oxygen will be attained in the area affected by the discharge; or (2) the proposed discharge will not lower instream concentrations of dissolved oxygen in any areas that are not meeting dissolved oxygen standards. Evaluation and modeling of dissolved oxygen impacts are conducted as discussed in the chapter in this document entitled “Modeling Dissolved Oxygen” (see page 83).

Toxic Pollutants Effluent limits will be established to avoid an increase in the permitted loading of a listed toxic pollutant unless: (1) it is demonstrated that water quality standards for the listed pollutant will be attained in the area affected by the discharge; or (2) water quality standards for the listed pollutant will be attained at the “end-of-pipe.” Demonstrations of standards attainment may include instream monitoring of listed pollutants.

However, no increase in loading will be allowed: (1) for toxic pollutants listed for drinking water concerns; (2) for toxic pollutants that accumulate in bottom sediments, fish tissue, or deep layers of water (typically indicated by a bioconcentration factor (BCF) equal to or greater than 1,000); or (3) where fishing advisories are present.

Dissolved Salts―TDS, Chloride, Sulfate Effluent limits will continue to be established as discussed in the chapter of this document entitled “Screening Procedures and Permit Limits for Total Dissolved Solids” (see page 174). The current procedures preclude additional TDS loadings when they would cause further increases in ambient TDS concentrations that are already at or above standards.

Bacteria Effluent limits are established to avoid an increase in permitted loading unless: (1) it can be demonstrated that water quality standards for the listed pollutant will be attained in the area affected by the discharge, or (2) water quality standards for the listed pollutant will be attained at the “end- of-pipe.”

Listings Based on Narrative Standards A proposed increase in loading of a pollutant that would cause or contribute to the existing violation of water quality standards will not be allowed.

Procedures for Discharges to Listed Water Bodies Requirements for discharges to listed water bodies apply to:

• • discharges that are directly to a listed water body • discharges to adjacent water bodies that are within a reasonable distance of and may affect a listed water body.

Application procedures, requirements for effluent screening by permittees, and review of the application for administrative completeness are the same as for discharges to unlisted water bodies. Effluent screening for permit applications is conducted in accordance with the sampling requirements in current application forms.

During review of permit applications, the TCEQ identifies discharges to listed water bodies and summarizes the listing in the modeling memo. For discharges that potentially increase the loading of a listed pollutant, the permit is developed in accordance with the requirements discussed beginning on page 57. The Wastewater Permitting Section will determine, when drafting the proposed permit, whether an increase in loading is anticipated.

Information on evaluating storm water discharges is contained in the section of this document entitled “Antidegradation Review of Storm Water Permits” on page 189.

Interim compliance periods and temporary variances will not allow an increase in loading of a listed pollutant that contributes to the violation of water quality standards.

For discharges that withdraw from and discharge to the same listed water body, an increase in permitted flow does not cause an “increase in loading” if it is demonstrated that the facility does not add listed pollutants to the discharge or cause other conditions that contribute to the violation of water quality standards.

Additional permit requirements will be imposed as necessary to address potential water quality impacts from listed pollutants.

The permit’s fact sheet or statement of basis/technical summary (which is publicly available) notes that the discharge is to a listed water body and the reasons why the water body is listed.

Applicability of Pollution Reduction Programs Pollution prevention programs of the TCEQ may focus on watersheds of listed water bodies where such programs can potentially reduce the loading of listed pollutants.

Additional pretreatment requirements may be considered for discharges from publicly owned treatment works to listed water bodies where industrial users of the wastewater system contribute listed pollutants.

Examples of Permitting to Listed Water Bodies • A proposed discharge is projected to increase the concentration of a listed pollutant in the area of the water body that is not attaining standards for that pollutant. The additional loading will not be permitted.

• • An increase in discharge flow is proposed, and the discharge contains significant concentrations of a listed pollutant (for example, a listed toxic pollutant is present at a concentration at or above the minimum analytical level―MAL). The additional flow may be permitted if permit limits are established that preclude an increase in loading of the listed pollutant by reducing its concentration.

• • For some pollutants, additional loading will not adversely affect water quality if no instream dilution is allowed, so that standards are attained at the “end-of-pipe.” This provision does not apply when a listed pollutant accumulates in bottom sediments, fish tissue, or deep layers of water. Such accumulation is typically indicated by a bioconcentration factor (BCF) equal to or greater than 1,000 or by an advisory for fish consumption.
• • For discharges that withdraw from and discharge to the same listed water body, an increase in discharge flow can be allowed if it is demonstrated that the facility is simply “passing through” the pollutant of concern, so that it does not add more of the listed pollutant to the discharge effluent or cause other conditions that contribute to the violation of water quality standards.
• • For discharges that are well upstream from a listed area, some pollutants, such as BOD, might be shown to completely dissipate by the time the discharge flow reaches the listed area.

Tier 2—Protecting High-Quality Waters Applicability Antidegradation reviews under Tier 2 ensure that where water quality exceeds the normal range of fishable/swimmable criteria, such water quality will be maintained unless lowering it is necessary for important economic or social development. The second tier of the antidegradation policy generally applies to water bodies that have existing, designated, or presumed uses of primary and secondary contact recreation and intermediate, high, or exceptional aquatic life waters. (Note that Tier 1 of the antidegradation policy applies to all water bodies, including those that are eligible for Tier 2 review.) TPDES permit amendments and new permits that allow an increase in loading are subject to review under Tier 2 of the antidegradation policy.

For Tier 2 reviews, the parameters of concern for individual water bodies may include:

• • dissolved oxygen • total dissolved solids • sulfate • chloride • pH • temperature • toxic pollutants • bacterial indicators of recreational suitability • radioactive materials

• • nutrients (phosphorus, nitrogen) • taste and odor • suspended solids • turbidity • foam and froth • oil and grease • any other constituents that could lower water quality.

Conditions that are usually not subject to an antidegradation review under Tier 2 include the following:

• • Increases in pollutant loading at a specific discharge point that result from consolidating existing wastewater from other discharge points, so that overall loadings to a particular water body are not increased.
• • A new or increased loading in an individual discharge that is either:

◦ authorized in a waste load evaluation (WLE) or total maximum daily load (TMDL) that has been certified as an update to the Water Quality Management Plan (WQMP); or

◦ authorized by a TPDES general permit,

provided that a Tier 2 review was previously conducted on the WLE, TMDL, or general permit.

• • A new or increased discharge authorized by a temporary or emergency order.
• • New data on effluent composition indicates that a pollutant that was either (1) not previously tested for or (2) not previously detected above the agency-specified minimum analytical level (MAL) is now detected above the current MAL, and there is no proposal to increase the loading of the pollutant.

Evaluating the Potential for Degradation of Water Quality The effect of a proposed discharge is compared to baseline water quality conditions in order to assess the potential for degradation of water quality. The applicable date for establishing baseline water quality conditions is November 28, 1975, in accordance with 40 CFR Part 131 (EPA standards regulation). Baseline conditions are estimated from existing conditions, as indicated by the latest edition of the Texas Water Quality Inventory or other available information, unless there is information indicating that degradation in ambient water quality has occurred in the receiving waters since November 28, 1975.

Analyses to assess the impact of a proposed discharge on water quality include procedures that are established in other chapters of this document, such as “Determining Water Quality Uses and Criteria” on page 14, “Evaluating Impacts on Water Quality” on page 20, and “Toxic Pollutants” on page 130.

Proposed increases in loading are initially screened to determine whether sufficient potential for degradation exists to require further analysis. This initial screening procedure does not define degradation. It is intended only as general guidance to indicate when an increase in loading is small enough to preclude the need for additional evaluation. The following guidelines are used for initial screening of existing and new discharges.

Existing Discharges Increases in permitted loading of less than 10% over the loading allowed by the existing discharge permit are usually not considered to constitute potential degradation if: (1) the increase will attain all water quality standards, (2) the aquatic ecosystem in the area is not unusually sensitive to the pollutant of concern, and (3) the discharge is not relatively large.

The cumulative effect of repeated small increases in successive permit actions or from multiple discharges may require additional screening evaluation, even though the current permit application may be for a less than 10% increase in loading for any constituents of concern.

Increases in permitted loading of 10% or greater are not automatically presumed to constitute degradation, but will receive further evaluation.

New Discharges New discharges that use less than 10% of the existing assimilative capacity of the water body at the edge of the mixing zone are usually not considered to constitute potential degradation as long as the aquatic ecosystem in the area is not unusually sensitive to the pollutant of concern. New discharges that use 10% or greater of the existing assimilative capacity are not automatically presumed to constitute potential degradation but will receive further evaluation. For constituents that have numerical criteria in the water quality standards, the following equation may be used to estimate changes in assimilative capacity:

100 [C P  C A ] % change  CC  C A

where: % change = the percent change to the assimilative capacity CP = the predicted concentration at the edge of the mixing zone CA = the ambient concentration at the edge of the mixing zone CC = the numerical criterion for the constituent of concern

This screening procedure is not applicable to dissolved oxygen, pH, or temperature. The screening procedure for nutrients is explained in a previous chapter of this document in the section entitled “Nutrients” beginning on page 26. Predicted concentrations at the edge of the mixing zone are calculated at applicable critical conditions using estimated effluent concentrations, which are based on available information, categorical limits, or other information. See the subsection of this document entitled “Procedure for Developing Permit Limits” on page 148 for more information on how the ambient concentration at the edge of the mixing zone is determined.

Additional Screening If needed, additional screening is conducted to assess the potential for degradation. If proposed loadings exceed additional screening guidelines, then further evaluation is needed. The additional screening guidelines do not define degradation. The cumulative effect of repeated small increases in successive permit actions may require additional screening evaluation.

Examples Where Degradation Is Unlikely to Occur The following examples are usually not considered to constitute degradation except where site-specific biological, chemical, or physical conditions in a water body create additional sensitivity or concern, or where background concentrations are adversely elevated:

• • Increased TSS loading—if effluent concentrations are maintained at 20 mg/L or less.
• • Increased temperature loading—if the “end-of-pipe” temperatures are not expected to be significantly higher than applicable instream temperature criteria.
• • Increased loading of recreational indicator bacteria—if the applicable instream criteria are maintained in the effluent at the “end-of-pipe”.
• • Increased loading of oxygen-demanding materials—if the dissolved oxygen in the “sag zone” is lowered by less than 0.5 mg/L from baseline instream concentrations, and if the potentially affected aquatic organisms are not unusually sensitive to changes in dissolved oxygen.
• • Increased loading of constituents that affect pH—if the instream criteria for pH in the nearest downstream segment are attained in the effluent at the “end-of-pipe”.
• • Increased loading of TDS, chloride, or sulfate in freshwater—if the instream criteria are attained in the effluent at the edge of the mixing zone at critical conditions.
• • Increased loading of total phosphorus, nitrate, or total nitrogen—if it can be reasonably demonstrated that detrimental increases to the growth of algae or aquatic vegetation will not occur.
• • Increased loading of toxic pollutants that are: ◦ below concentrations that require an effluent limit based on water quality criteria or require monitoring and reporting as a permit condition.

◦ not bioaccumulative (that is, the bioconcentration factor is less than 1,000).

◦ not a potential cause of concern to a public drinking water supply.

◦ not discharged in an area where there are aquatic organisms of unusual sensitivity to the specific toxicant of concern.

Examples Where Degradation Is Likely to Occur The following examples are intended to provide general guidelines as to when degradation becomes likely. The examples do not define degradation, nor do they address all pollutants and situations that can cause degradation. Final determinations are case-specific and can depend on the characteristics of the water body and local aquatic communities. Lower increases in loading may constitute degradation in some circumstances, and higher loadings may not constitute degradation in other situations. Examples where degradation is likely to occur include:

• • Increased loading of oxygen-demanding substances that is projected to decrease dissolved oxygen by more than 0.5 mg/L for a substantial distance in a water body that has exceptional quality aquatic life and a relatively unique and potentially sensitive community of aquatic organisms.
• • Increased loading of bioaccumulative pollutants (that is, the bioconcentration factor is greater than 1,000) that use more than 10% of the assimilative capacity at the edge of the human health mixing zone, or a substantial increase in the loading of a toxic pollutant that would directly affect an important or unusually sensitive aquatic organism.
• • Increased loading of phosphorus and/or nitrogen into a reservoir that supplies public drinking water, if the loading would result in significant elevations in algae or potentially detrimental aquatic vegetation over a substantial area.
• • A new discharge that is made directly into a tidal wetland or estuary and that would be expected to detrimentally affect emergent or submerged vegetation over a substantial area.
• • Increased loading of TSS that would produce a visible turbidity plume extending past the designated aquatic life mixing zone.

Evaluation of Alternatives and Economic Justification When initial and additional screening under Tier 2 preliminarily indicates that the proposed discharge is expected to degrade water quality, then the applicant is notified so that the following information can be provided to TCEQ by the applicant:

• • Any additional information about the nature of the discharge and the receiving waters that could affect the evaluation of whether degradation is expected.

• • An analysis of alternatives to the proposed discharge that could eliminate or reduce the anticipated degradation, and an assessment of cost and feasibility for reasonable alternatives.
• • An evaluation of whether the proposed discharge will provide important economic and social development in the area where the affected waters are located, considering factors such as:

◦ Employment ◦ Increased production that improves local economy ◦ Improved community tax base ◦ Housing ◦ Correction of an environmental or public health problem.

Agency Review of Degradation When degradation is anticipated, the TCEQ reviews the preliminary determination of potential degradation, the evaluation of alternatives, and economic and social justification. The TCEQ then determines whether a lowering of water quality is expected from the proposed discharge. If it is, the TCEQ then determines whether the lowering of water quality is necessary for important economic or social development and whether reasonable alternatives to the lowering of water quality are unavailable. The TCEQ may also refer questions concerning an antidegradation review to the State Office of Administrative Hearings for further review and consideration for an administrative hearing. Any proposed TPDES permit that allows degradation is subject to EPA review and approval.

Tier 3—Outstanding National Resource Waters Outstanding national resource waters (ONRWs) are defined in § 307.5(b)(3) of the Standards as high-quality waters within or adjacent to national parks and wildlife refuges, state parks, wild and scenic rivers designated by law, and other designated areas of exceptional recreational or ecological significance. In accordance with § 307.5(b)(3) of the Standards, the quality of such waters will be maintained and protected. No increase in pollution that could cause degradation of water quality is allowed into ONRWs.

ONRWs are specifically designated in § 307.5 of the Standards. Any designation of an ONRW should include a geographic description of the ONRW and of the applicable watershed to which the restrictions on increased loadings apply. Currently there are no designated ONRWs in Texas.

Watershed Protection Rules Additional protection of specific, sensitive watersheds is provided by requirements for wastewater discharge permits in 30 TAC Chapter 311. Requirements for discharges in specified watersheds can include phosphorus limits, advanced treatment of carbonaceous biochemical oxygen demand (CBOD) and ammonia-nitrogen, and prohibitions of discharge except by irrigation. Water bodies and their adjacent watersheds that are addressed in 30 TAC Chapter 311 include:

Subchapter of Segment Water Body/Watershed 30 TAC 311 0807 Lake Worth G 0809 Eagle Mountain Reservoir G 0811 Bridgeport Reservoir G 0818 Cedar Creek Reservoir G 0828 Lake Arlington G 0830 Benbrook Lake G 0836 Richland-Chambers Reservoir G 1002 Lake Houston D 1403 Lake Austin A 1404 Lake Travis A 1405 Marble Falls Lake F 1406 Lake Lyndon B. Johnson F 1407 Inks Lake B 1408 Lake Buchanan B 1427 Onion Creek E Colorado River Below Town Lake/ 1428 E Lady Bird Lake Colorado River Above La Grange 1434 E (portion above City of Smithville) 2425 Clear Lake C

In addition to the above rules, additional protection is provided to the recharge and contributing zones of the Edwards Aquifer in 30 TAC Chapter 213.

Public Notice The Notice of Application and Preliminary Decision (public notice) concerning a proposed permit or permit amendment includes any preliminary additional uses assigned to unclassified receiving waters. If the proposed discharge is to a water body listed as impaired on the current § 303(d) List, this fact is noted in the permit’s fact sheet, statement of basis/technical summary, or other publicly available information.

When the proposed permit affects receiving waters whose quality is exceptional, high, or intermediate, the public notice also indicates whether a lowering of water quality is anticipated. Information in the public notice about uses and antidegradation is indicated as preliminary and is subject to additional review and revision before approval of the permit by the TCEQ. A summary of anticipated impacts and the criteria for preliminary determinations of whether degradation will occur is publicly available in the permit file.

The public notice provides opportunity to comment and to submit additional information on the determination of existing uses and criteria, anticipated impacts of the discharge, baseline conditions, the necessity of the discharge for important economic or social development if degradation of water quality is expected under Tier 2, and any other applicable aspects of the antidegradation policy.

Mixing Zones and Critical Conditions

General Information This chapter describes how the TCEQ assigns mixing zones (MZs) and zones of initial dilution (ZIDs) and determines their associated critical mixing conditions for discharges into different types of water bodies.

Mixing zones are defined in permits for:

• • domestic discharges with a flow of 1 million gallons per day (MGD) or greater (or with numerical criteria and/or whole effluent toxicity tests specifically expressed as permit limitations).
• • industrial discharges (excepting those that consist entirely of storm water runoff).

A mixing zone may not encompass an intake for a domestic drinking water supply that includes an organized treatment system as defined in 30 TAC Chapter 290―Public Drinking Water.

Thermal mixing zones and thermal impacts may be separately considered by the TCEQ in accordance with (1) the general criteria for temperature in the Texas Surface Water Quality Standards in § 307.4(f), or (2) provisions concerning thermal discharges in federal Clean Water Act § 316. Evaluations and permit conditions will ensure that temperature in the state shall be maintained so as to not interfere with the reasonable use of surface waters; or so as to assure the protection and propagation of balanced, indigenous populations of shellfish, fish, and wildlife.

Mixing Zones and ZIDs for Aquatic Life Protection Mixing zone size and shape may be varied in individual permits to account for differences in:

• • stream flow • bay, estuary, and reservoir morphometry • effluent flow • stream geometry • ecological sensitivity at the discharge site • zone of passage concerns • discharge structures

ZIDs are specified for different receiving water types in § 307.8(b)(2) of the Standards and are not usually specified in individual permits. Complete mixing of effluent and receiving waters is assumed at mixing zone boundaries unless available information shows otherwise.

Intermittent Streams and Ditches No mixing zone is assigned to discharges to intermittent streams or ditches or to intermittent streams with perennial pools.

Perennial Streams, Ditches, and Rivers Mixing zones for discharges into perennial streams, ditches, or rivers are expressed in the permit in terms of longitudinal stream distance. The typical mixing zone extends 300 feet downstream and 100 feet upstream from the discharge point. Mixing zones may not preclude passage of free swimming or drifting aquatic organisms to the extent that aquatic life use is significantly affected.

ZIDs may not exceed a size of 60 feet downstream and 20 feet upstream from the point of discharge and may not encompass more than 25% of the volume of the stream flow at or above the seven-day, two-year low-flow (7Q2). ZIDs cannot extend across perennial streams, ditches, or rivers or impair migration of aquatic organisms.

Lakes and Reservoirs Mixing zones for discharges into lakes and reservoirs are normally expressed in the permit as a radius that extends over the receiving water in all directions from the point of discharge. The typical mixing zone radius is no greater than 100 feet but does not exceed one-half the width of the receiving water at the discharge point.

ZIDs may not exceed a 25-foot radius in all directions (or equivalent volume or area for discharges through diffuser systems) from the point of discharge and are normally assigned a value that is one-fourth the radius of the mixing zone. This is generally equivalent to 6.3% of the mixing zone surface area.

Bays, Estuaries, and Wide Tidal Rivers Mixing zones for discharges into bays, estuaries, and wide tidal rivers (≥ 400 feet across) are expressed in the permit as a radius that extends over the receiving water in all directions. The typical mixing zone radius is no greater than 200 feet but does not exceed one-half the width of the receiving water at the discharge point.

ZIDs may not exceed a 50-foot radius in all directions (or equivalent volume or area for discharges through diffuser systems) from the point of discharge and are normally assigned a value that is one-fourth the radius of the mixing zone.

Narrow Tidal Rivers Mixing zones and ZIDs for discharges into narrow tidal rivers depend on the availability and use of upstream flow data to calculate effluent percentages. If such flow information is available and used, the mixing zone and ZID are defined as for perennial streams, ditches, and rivers. If flow information is not available or not used, the mixing zone and ZID are defined as for bays, estuaries, and wide tidal rivers.

Wetlands and Sand or Mud Flats Generally, no mixing zone is assigned to discharges to wetlands or to sand or mud flats. Discharges to permanently inundated wetlands may be assigned a mixing zone. The size of the mixing zone is evaluated on a case-by-case basis.

Critical Conditions for Aquatic Life Protection Effluent concentration limits for specific toxic materials are calculated, using critical mixing conditions, to meet numerical standards for chronic toxicity at the edge of the mixing zone and numerical standards for acute toxicity at the edge of the ZID (see the section of this document entitled “Deriving Permit Limits for Aquatic Life Protection” on page 131). The effluent fraction at the edge of the mixing zone, when expressed as a percentage, is also referred to as the critical dilution, and is used as the primary concentration for whole effluent toxicity testing (see the subsection of this document entitled “Dilution Series, Dilution Water, and Type of WET Test” on page 110).

Intermittent Streams and Ditches For discharges into intermittent streams or ditches with minimal aquatic life uses, acute toxic criteria apply at the point of discharge, and no dilution is assumed (that is, the critical dilution is 100%). If the discharge reaches a perennial water body within three miles, chronic toxic criteria apply at that perennial water body (see subsequent discussions. For discharges into intermittent streams or ditches with limited, intermediate, high, or exceptional aquatic life uses created by perennial pools, acute and chronic toxic criteria apply at the point of discharge, and no dilution is assumed (that is, the critical dilution is 100%).

Perennial Streams, Ditches, and Rivers For discharges into perennial streams, ditches, and rivers, chronic toxic criteria apply at the edge of the mixing zone in the perennial water body using the effluent percentage that occurs at the 7Q2. For streams and rivers that are dominated by springflow, an alternative critical low-flow value may be calculated (see page 77). QE % effluent at edge of MZ   100% QE  7Q2

In addition, acute toxic criteria apply at the edge of the ZID in the perennial water body using the effluent percentage that occurs at the one- day, two-year low flow (1Q2), which is estimated as 25% of the 7Q2 (or 25% of the alternative critical low-flow value for streams and rivers that are dominated by springflow). The following equations are used to calculate the effluent percentages:

QE % effluent at edge of ZID   100% QE  0.25(7Q2)

where: QE = effluent flow

For more information about what effluent flow is used in these equations, see the section of this document entitled “Deriving Permit Limits for Aquatic Life Protection” on page 131. For more information on how the 7Q2 is determined, see the section of this document entitled “Determining the 7Q2” on page 75.

Lakes, Reservoirs, Bays, Estuaries, and Wide Tidal Rivers Critical conditions at mixing zone boundaries for discharges into lakes, reservoirs, bays, estuaries, and wide tidal rivers are estimated from appropriate models of discharge plume dispersion. To estimate the percent effluent, TCEQ uses the horizontal Jet Plume equation5:

2.8  D  (3.14)1 / 2 % effluent   100 % R

where: D= pipe diameter (ft) that corresponds to effluent flow (based on Manning’s equation, but not less than 3 ft) R= radius (ft) of mixing zone or ZID

Model results and empirical data indicate that the following initial assumptions are appropriate for discharges of less than or equal to 10 MGD:

• • The percentage of effluent at the edge of the mixing zone is 15% for lakes and 8% for bays, estuaries, and wide tidal rivers.
• • The percentage of effluent at the edge of the ZID is 60% for lakes and 30% for bays, estuaries, and wide tidal rivers.

These assumed critical dilutions are based on a pipe diameter of 3 feet and the standard mixing zone sizes of 100 feet (lakes and reservoirs) and 200 feet (bays, estuaries, and wide tidal rivers). If it is necessary to assign a smaller mixing zone or larger pipe size, these effluent percentages will increase. TCEQ staff assigns a critical dilution of 100% effluent for discharges equal to or greater than 100 MGD.

Data from appropriately performed effluent dispersion dye studies or effluent mixing models may be used to vary from the conservative initial dilution assumptions.

Narrow Tidal Rivers Critical conditions at mixing zone boundaries for discharges into narrow tidal rivers (< 400 feet across) are calculated as for perennial streams and rivers if upstream flow data from USGS gages or other sources are available. The typical mixing zone extends 300 feet downstream and 100 feet upstream from the discharge point.

5 The horizontal Jet Plume equation is based on Fischer, H.B., E.J. List, R.C.Y. Koh, J. Imberger, N.H. Brooks, 1979. Mixing in Inland and Coastal Waters. Chapter 9: Turbulent Jets and Plumes, p. 328.

In the absence of site-specific data such as dispersion dye studies or nearby flow measurements, minimum effluent percentages of 8% at the edge of the mixing zone and 30% at the edge of the ZID are assumed. Because mixing conditions in tidal rivers with upstream flow are not well understood, these minimum effluent percentages should provide narrow tidal rivers with the same level of protection given to bays, estuaries, and wide tidal rivers.

If upstream flow data from USGS gages or other sources is unavailable, the horizontal Jet Plume equation is used to calculate critical conditions. In these cases, the mixing zone radius is one-half the width of the narrow tidal river at the discharge point, and the critical dilutions are greater than 8% at the edge of the mixing zone and greater than 30% at the edge of the ZID. TCEQ staff may also consider tracer analyses, empirical data, or other models to determine site-specific instream dilution in narrow tidal rivers.

Wetlands and Sand or Mud Flats For discharges into wetlands or sand or mud flats, very little mixing is likely to occur. Therefore, in the absence of site-specific data (such as dispersion dye studies), acute and chronic toxic criteria apply at the point of discharge, and no dilution is assumed (that is, the critical dilution is 100%).

Determining the 7Q2 The 7Q2 is defined in the Standards as “the lowest average stream flow for seven consecutive days with a recurrence interval of two years, as statistically determined from historical data.” Effluent limits in TPDES wastewater discharge permits are designed to maintain the applicable numerical water quality standards for the protection of aquatic life when instream flows are at or above the 7Q2.

Many of the numerical water quality standards, as established in the Standards, do not apply when stream flow conditions are less than “critical low-flow conditions.” Generally, critical low-flow conditions are determined as the 7Q2. The following criteria apply at and above the 7Q2:

• • numerical criteria for dissolved oxygen
• • numerical criteria for temperature and pH
• • numerical criteria for E. coli, Enterococci, and fecal coliform
• • numerical criteria to protect aquatic life from acute toxicity (apply at and above ¼ of the 7Q2)

• • numerical criteria to protect aquatic life from chronic toxicity
• • requirements to preclude chronic toxicity in whole effluent toxicity testing

For purposes of water quality regulation, the 7Q2 is calculated from approximately 30 years of flow data at USGS or International and Boundary Water Commission (IBWC) gages. A shorter period of record is used if the longer period of record is unavailable or inappropriate. If a major, permanent hydrologic alteration has occurred, such as upstream reservoir construction, then only the flows recorded after the alteration are used in the 7Q2 calculation. Gage data is also examined for trends and the period of record may be adjusted if a trend is identified.

Appendix C of this document lists 7Q2s for classified segments (see page 217), but the 7Q2 is usually recalculated annually to incorporate new flow data. Values in Appendix C should be verified with the Water Quality Assessment Section to ensure they have not changed since the last date of publication of this document.

If less than five years of continuous daily average flow data is available, the tenth percentile flow is normally used as an estimate of the 7Q2. Otherwise, the following procedure is used in a FORTRAN program to calculate the 7Q2 using daily average flow data from a gage:

1. Determine the minimum seven-day average flow for each year of data. 2. Rank the minimum seven-day average flows from lowest to highest.

3. Calculate the recurrence interval for each minimum seven-day average flow. If N is the total number of years of flow data, then the recurrence interval is (N+1)/rank.

4. The 7Q2 is the minimum seven-day average flow with a recurrence interval of 2. If an even number of years is used, interpolate the 7Q2.

In the absence of USGS or IBWC flow data, other sources of flow information may be used to estimate the 7Q2. These sources include self- reporting data from upstream dischargers, Surface Water Quality Monitoring (SWQM) stations (including Clean Rivers Program targeted monitoring), or other data sources as available. Estimates of the 7Q2 using this kind of data are generally based on the 10th percentile of the available flow data or on comparisons with a nearby USGS or IBWC gage.

In the absence of flow data, a drainage area ratio is used to estimate the 7Q2. The drainage area above the point of discharge or point of interest is determined, a nearby gage is selected for the comparison, and based on work done by the USGS 6, the following equation is used to estimate the 7Q2:

0.89  DAd  7Q 2 d  7Q 2 g     DA g 

where: 7Q2d = 7Q2 just above the discharge point or point of interest DAd = drainage area above the discharge point or point of interest 7Q2g = 7Q2 of the gage DAg = drainage area above the gage

Determining Critical Low-Flows for Streams and Rivers that are Dominated by Springflow Streams and rivers that are dominated by springflow typically have 7Q2s that correspond to a much higher percentile of the flow data than streams and rivers that are not dominated by springflow. For example, the 7Q2 of a stream or river that is not dominated by springflow tends to be about a 10th percentile; the 7Q2 of a stream or river that is dominated by spring flow tends to be a 20th percentile or greater. In addition, it is not unusual for spring-fed streams to contain federally listed endangered or threatened species.

In order to avoid providing less protection to spring-fed systems than is afforded to other streams and rivers, the TCEQ employs the following statistical approaches, using all available flow data, to derive the critical low-flow for spring-fed streams and rivers:

• • for spring-fed streams that contain federally-listed endangered or threatened species (as listed in Appendix B of this document), the critical low-flow will be the 0.1 percentile of the lognormal fit to the flow data. Where determined to be appropriate, for spring-fed streams that contain state-listed endangered or threatened species, the critical low-flow will be the 0.1 percentile of the lognormal fit to the flow data.

6 Asquith, William H.; Roussel, Meghan C.; Vrabel, Joseph. 2006. Statewide Analysis of the Drainage- Area Ratio Method for 34 Streamflow Percentile Ranges in Texas. United States Geological Survey Scientific Investigations Report 2006-5286.

• • for spring-fed streams that do not contain federally-listed endangered or threatened species (as listed in Appendix B of this document), or state-listed endangered or threatened species, the critical low-flow will be the 5th percentile of the flow data.

Mixing Zones and Critical Conditions for Human Health Protection Intermittent Streams and Ditches No human health mixing zone is applied to discharges to intermittent streams with no significant aquatic life uses, since human health toxic criteria do not apply. If the effluent reaches perennial waters or an intermittent stream with perennial pools within three miles of the discharge point, human health criteria apply at those waters.

Intermittent Streams with Perennial Pools Human health mixing zones for discharges into intermittent streams with perennial pools typically extend 300 feet downstream and 100 feet upstream from the discharge point. Human health criteria apply at the edge of the human health mixing zone using the effluent percentage that occurs at the harmonic mean flow. The equation under “Perennial Streams, Ditches, and Rivers” is used to calculate the human health effluent percentage.

Perennial Streams, Ditches, and Rivers Human health mixing zones for discharges into perennial streams, ditches, or rivers typically extend 300 feet downstream and 100 feet upstream from the discharge point. Human health criteria apply at the edge of the human health mixing zone using the effluent percentage that occurs at the harmonic mean flow. The following equation is used to calculate the human health effluent percentage:

QE % effluent at edge of HH MZ   100% QE  HM where: QE = effluent flow HM = harmonic mean flow

For more information on what effluent flow is used in this equation, see the section of this document entitled “Deriving Permit Limits for Human Health Protection” on page 140. For more information on how the harmonic mean flow is determined, see the section of this document entitled “Determining the Harmonic Mean Flow” on page 80.

Lakes, Reservoirs, Bays, Estuaries, and Wide Tidal Rivers The typical human health mixing zone radius for lakes and reservoirs extends no greater than 200 feet in all directions over the receiving water from the point of discharge. The typical human health mixing zone radius for bays, estuaries, and wide tidal rivers extends no greater than 400 feet in all directions over the receiving water from the point of discharge.

Critical conditions at human health mixing zone boundaries for discharges into lakes, reservoirs, bays, estuaries, and wide tidal rivers are estimated from appropriate models of discharge plume dispersion. To estimate the effluent percentage, TCEQ uses the horizontal Jet Plume equation 7:

2.8  D  (3.14)1 / 2 % effluent   100 % R

where: D= pipe diameter (ft) that corresponds to effluent flow (based on Manning’s equation, but not less than 3 ft) R= radius (ft) of human health mixing zone

Model results and empirical data indicate that the following initial assumptions are appropriate for discharges of less than or equal to 10 MGD:

• • The percentage of effluent at the edge of the human health mixing zone is 8% for lakes and reservoirs.
• • The percentage of effluent at the edge of the human health mixing zone is 4% for bays, estuaries, and wide tidal rivers.

These assumed effluent percentages are based on a pipe diameter of 3 feet and the standard human health mixing zone sizes of 200 feet (lakes and reservoirs) and 400 feet (bays, estuaries, and wide tidal rivers). If it is necessary to assign a smaller mixing zone or a larger pipe size, these effluent percentages will increase. TCEQ staff assigns an effluent percentage of 100% for discharges equal to or greater than 100 MGD.

Data from appropriately performed effluent dispersion dye studies or effluent mixing models may be used to vary from the conservative initial dilution assumptions.

7 The horizontal Jet Plume equation is based on Fischer, H.B., E.J. List, R.C.Y. Koh, J. Imberger, N.H. Brooks, 1979. Mixing in Inland and Coastal Waters. Chapter 9: Turbulent Jets and Plumes, p. 328.

Narrow Tidal Rivers In narrow tidal rivers, the critical conditions for human health protection are calculated as for perennial streams and rivers if upstream flow data from USGS or IBWC gages or other sources are available. In this case, the human health mixing zone typically extends 300 feet downstream and 100 feet upstream from the discharge point.

In the absence of site-specific data such as dispersion dye studies or nearby flow measurements, a minimum effluent percentage of 4% at the edge of the human health mixing zone is assumed. Because mixing conditions in tidal rivers with upstream flow are not well understood, this minimum effluent percentage should provide narrow tidal rivers with the same level of protection given to bays, estuaries, and wide tidal rivers.

If upstream flow data from USGS or IBWC gages or other sources is unavailable, the horizontal Jet Plume equation is used to calculate the effluent percentage. In these cases, the mixing zone radius is equal to the width of the river at the discharge point, and the effluent percentage is greater than 4% at the edge of the human health mixing zone.

More protective human health critical conditions may be used where bioaccumulative or persistent pollutants are a concern. TCEQ staff may also consider tracer analyses, empirical data, or other models to determine site-specific instream dilution in narrow tidal rivers.

Wetlands and Sand or Mud Flats Generally, no human health mixing zone is assigned to discharges to wetlands or sand or mud flats. Discharges to permanently inundated wetlands may be assigned a human health mixing zone whose size is evaluated on a case-by-case basis. Very little mixing is likely to occur in a wetland or on a sand or mud flat, so in the absence of site-specific data (such as dispersion dye studies), human health criteria apply at the point of discharge, and no dilution is assumed (that is, the effluent percentage is 100%).

Determining the Harmonic Mean Flow The harmonic mean flow is defined in the Standards as “a measure of mean flow in a water course which is calculated by summing the reciprocals of the individual flow measurements, dividing this sum by the number of measurements, and then calculating the reciprocal of the resulting number.” Harmonic mean flows are usually, but not always, greater than 7Q2s. Effluent limits in TPDES wastewater discharge permits are designed to maintain the applicable numerical water quality standards as long-term averages for the protection of human health.

For purposes of water quality regulation, the harmonic mean flow is calculated from approximately 30 years of flow data at USGS or IBWC gages. A shorter period of record is used if the longer period of record is unavailable or inappropriate. If a major, permanent hydrologic alteration has occurred, such as upstream reservoir construction, then only the flows recorded after the alteration are used in the harmonic mean calculation. Gage data is also examined for trends, and the period of record may be adjusted if a trend is identified.

Harmonic mean flows for designated stream segments are listed in Appendix C of this document, but the harmonic mean flow is usually recalculated annually to incorporate new flow data. Values in Appendix C should be verified with the Water Quality Assessment Section to ensure they have not changed since the last date of publication of this document.

The following equation is used to calculate the harmonic mean flow for any set of flow data:

1  NT  N 0 1    Q   N  N0  HM   i 1 i    T   NT  N 0   NT     

where: HM = harmonic mean flow Qi = nonzero flow NT = total number of flow values N0 = number of zero flow values

In order to calculate effluent limits based on water quality criteria for human health protection, a harmonic mean flow is determined for all perennial streams and for streams that are intermittent with perennial pools.

Sometimes these streams have days on which measured flow is zero. Because a zero flow cannot be used in the calculation of harmonic mean flow, the second term in the harmonic mean equation is an adjustment factor used to lower the harmonic mean to compensate for days when the flow was zero. This is the same correction used by the EPA computer program DFLOW. (Note that if there are no days on which the flow was zero, the adjustment term is equal to unity.)

In the absence of USGS or IBWC flow data, other sources of flow information may be used to estimate the harmonic mean. These sources include self-reporting data from upstream dischargers, Surface Water Quality Monitoring stations (including Clean Rivers Program targeted monitoring), or other data sources as available. Estimates of the harmonic

mean using this kind of data are generally based on the harmonic mean of the available flow data or on comparisons with a nearby USGS or IBWC gage.

In the absence of flow data, a drainage area ratio is used to estimate the harmonic mean flow. The drainage area above the point of discharge or point of interest is determined, a nearby gage is selected for the comparison, and based on work done by the USGS 8, the following equation is used to estimate the harmonic mean flow:

0.89  DAd  HM d  HM g     DA g 

where: HMd = harmonic mean flow just above the discharge point or point of interest DAd = drainage area above the discharge point or point of interest HMg = harmonic mean flow of the gage DAg = drainage area above the gage

Diffusers Diffusers installed at the end of discharge pipes may increase mixing and lower critical dilutions. The model most commonly used to design diffusers and evaluate the resulting mixing conditions is CORMIX. Mixing is evaluated under both summer and winter temperature conditions and at different combinations of effluent and receiving water densities. The highest effluent percentages at the edge of the mixing zone and ZID are used to determine water quality-based effluent limits for the protection of aquatic life. The highest effluent percentage at the edge of the human health mixing zone is used to determine water quality-based effluent limits for the protection of human health.

8 Asquith, William H.; Roussel, Meghan C.; Vrabel, Joseph. 2006. Statewide Analysis of the Drainage- Area Ratio Method for 34 Streamflow Percentile Ranges in Texas. United States Geological Survey Scientific Investigations Report 2006-5286.

Modeling Dissolved Oxygen

General Information Numerical criteria for dissolved oxygen correspond to specific aquatic life use categories as specified in Table 1 on page 16 of this document. All classified water bodies have numerical dissolved oxygen criteria specified in the Standards. All unclassified water bodies have either assigned or presumed uses, depending on data availability. In cases where data indicate the appropriate use is lower than the presumption, the appropriate use has to be adopted as part of the Standards before it can be used to set permit limits.

All TPDES applications for facilities that may decrease a water body’s dissolved oxygen are evaluated to determine what effluent limits are needed to maintain appropriate dissolved oxygen levels. Numerical models or other techniques are used to develop permit limits for oxygen- demanding constituents, in order to ensure the attainment of numerical criteria for dissolved oxygen.

Model Selection and Inputs Model selection depends on factors such as:

• • the type of water body to be analyzed • the type and quantity of available site-specific information • the location of the discharge point • the availability of previously developed models.

If available, waste load evaluations (WLEs), total maximum daily loads (TMDLs), or models calibrated to site-specific information are used to generate permit limits. In the absence of these, simplified screening level methods are used. These methods can be used with little site-specific information, but substituting site-specific values for default parameters is encouraged when available. The 24-hour mean dissolved oxygen is the principal criterion of concern in these analyses. Effects on dissolved oxygen due to the presence of aquatic plants are usually not considered.

Additional scrutiny is given to applications for discharges that enter water bodies with impaired dissolved oxygen levels. Impaired water bodies are listed on the state’s Clean Water Act Section § 303(d) List. The § 303(d) List is developed by the Surface Water Quality Monitoring Program in cooperation with the TMDL Program.

Screening Level Methods Nontidal Streams and Rivers To evaluate discharges into nontidal streams and rivers without specific WLEs, TMDLs, or other calibrated models, the TCEQ uses uncalibrated steady-state models. The preferred model for these analyses is QUAL-TX. Other public domain models may also be used. Using this approach, effluent limits may be derived for the following parameters: biochemical oxygen demand (BOD) or carbonaceous biochemical oxygen demand (CBOD), ammonia-nitrogen (NH3-N), and dissolved oxygen (DO).

Apart from discharge flow and quality, the most important model inputs for this approach can be categorized as follows:

• • stream hydraulic characterization • chemical kinetic rates • reaeration rates • critical conditions • background water quality

Many of these parameters are stipulated in a modeling memorandum of agreement (MOA) between the TCEQ and the EPA (see page 99). The following paragraphs describe these model inputs in more detail.

Stream Hydraulic Characterization Site-specific hydraulic information is used if it is available and of acceptable quality. In the absence of site-specific hydraulic information, generalized hydraulic equations are adopted for the model analysis. The TCEQ has developed these equations using data collected during studies performed throughout the state, and the coefficients represent the median values from those data.

Chemical Kinetic Rates The most important kinetic rates for dissolved oxygen analysis are: aerobic CBOD decay rate (Kd), ammonia-nitrogen oxidation rate (Kn), and sediment oxygen demand (SOD). A statistical analysis of rates used in previous calibrated and approved WLE models was performed to arrive at representative default rates. Normality tests performed on these data sets indicate that they are approximately lognormally distributed. The data used in the statistical analysis were taken from approximately 1,300 calibrated model reaches from water bodies throughout the state. For uncalibrated QUAL-TX modeling, the median value for Kd and Kn is normally used. For SOD, a value equivalent to approximately the 75th percentile is used. These values are:

• • Kd of 0.10/day • Kn of 0.30/day • SOD of 0.35 g/m2-day.

These rates are expressed at a standard temperature of 20ºC and are corrected to the temperature or temperatures used in the modeling analysis.

Reaeration Rates Reaeration rates account for the oxygen exchange between the atmosphere and the water body. Typically, an equation relating stream hydraulic properties to reaeration rate is used to estimate this parameter. The preferred equation for use in dissolved oxygen models of streams and rivers is the Texas Equation:

1.923 V 0.273 K 2 (at 20C)  D 0.894

where: K2 = reaeration rate (day-1) V = average stream velocity (m/s) D = average stream depth (m)

This equation was derived from regression of measured reaeration and hydraulic data collected throughout the state and is considered to be adequate for most Texas streams. The Texas Equation can be reliably applied to streams with depths between 0.2 and 1.0 meters coupled with velocities between 0.01 and 0.30 m/s. In specific cases where stream depth or velocity falls outside these ranges, other reaeration equations may be used. K2 is limited to a maximum value of 10/day at 20ºC, and the minimum value for this parameter is not allowed to go below the value calculated from the following equation:

0.6 K 2 min (at 20C)  D

where: K2min = minimum allowable reaeration rate (day-1) D = average stream depth (m)

Critical Conditions Critical conditions are those combinations of environmental conditions and wastewater inputs that typically result in the lowest dissolved oxygen levels in a water body. Critical conditions are defined by three primary parameters: ambient flow, wastewater flow, and ambient water temperature.

• • Simplified modeling of streams and rivers is performed using low ambient flow values—either the seven-day, two-year low-flow (7Q2) or flows specified in Table 4 (see page 90) or Tables 4a-4e (see pages 96-99), as appropriate. If base flow information is not available to estimate the 7Q2, then a value of 0.1 ft3/s is usually assumed for perennial streams, and a value of 0.0 ft3/s is used for intermittent streams. For perennial streams, 7Q2 flows may also be estimated using a proportional watershed approach or similar technique. Tenth percentile stream flows may be used to develop seasonal permit limits if measured flow data is readily available. For more information on the flows in Table 4, see the section of this chapter entitled “Critical Low- Flow Values for East and South Texas Streams” on page 88. For more information on the flows in Tables 4a-4e, see the section of this chapter entitled “Regression Equation for Establishing Critical Low- Flows in Specific Water Bodies in the Cypress Creek Basin” on page 92.
• • For renewal applications, the wastewater flow used in the model is the existing permitted average flow or flows of the facility as reflected in the current permit. For new or amendment applications, the wastewater flow used in the model is the proposed average flow or flows.
• • Model analyses for effluent limits are usually performed with summer temperatures. The temperature is normally assumed to be 30.5ºC unless critical low-flows reliably occur only at other temperatures. Alternative critical temperatures can be used if justifiable based on analysis of measured temperatures.

For the development of seasonal permit limits, the following temperatures/derivation methodologies are used:

◦ Non-Summer Months: The ninetieth percentile temperature for each month is used to assess compliance with general dissolved oxygen criteria.

◦ Summer Season (three hottest months): The mean of the average monthly temperatures for each of the three hottest months of the year plus the average of the standard deviations for these months is used to assess compliance with general dissolved oxygen criteria.

◦ Spawning Season: A temperature of 22.8EC is used to assess compliance with spawning season DO criteria contained in Table 1 of this document. Monthly average temperatures are used to determine months when spawning criteria apply. Compliance with the general dissolved oxygen criteria during the spawning month(s) is evaluated using appropriate ninetieth percentile temperature(s).

Ninetieth percentile temperatures are developed from data measured on the stream under evaluation if possible. In the absence of these data or if the amount of data is insufficient, the estimated ninetieth percentile values from data measured at USGS or IBWC gaging station(s) from similar water bodies are used.

Background Water Quality Simplified modeling normally employs assumptions for background water quality. These assumptions include an ultimate BOD concentration of 3 mg/L, an ammonia-nitrogen concentration of 0.05 mg/L, and a dissolved oxygen value equivalent to approximately 80% saturation at the model temperature. Alternatively, other values may be used based on analysis of measured data.

Tidal Water Bodies, Ponds, and Lakes

Tidal Water Bodies Tidal streams or rivers may be evaluated using an uncalibrated QUAL-TX model or other suitable technique. Bays can be evaluated using previously developed calibrated models, judicious use of a CSTR (continuously stirred tank reactor) model, or best professional judgment. Near-field dilution models may be used to provide supplementary information.

Ponds Small impoundments such as ponds may be evaluated using a CSTR model or other suitable technique.

Lakes and Reservoirs Due to the highly variable nature of potential discharge locations in large lakes and reservoirs, no single screening level modeling technique is

satisfactory for evaluating these discharges. Therefore, the evaluation method employed by TCEQ staff comprises a variety of techniques. While it is desirable to use mathematical models to determine treatment requirements, in some cases an appropriate model cannot be feasibly developed due to the lack of crucial site-specific information or to the large amount of time needed to develop a model. The following factors are considered in the review of these discharges:

• • the size and quality of the proposed discharge;
• • its proximity to other dischargers;
• • the location of the outfall relative to areas that are likely to be highly limiting (such as small coves, flooded creek channels, or other areas with restricted interaction and water exchange with the main body of the reservoir); and
• • suitability of analyzing the discharge using a predictive analytical tool.

Direct discharges to relatively open waters can be evaluated using previously developed calibrated models, judicious use of a CSTR model, or best professional judgment. Near-field dilution models may be used to provide supplementary information. Analyses of discharges to lakes and reservoirs are performed using dimensions that would be present at normal pool elevation.

Tributaries of Lakes and Reservoirs Discharges to tributaries of lakes and reservoirs are generally evaluated with a model or series of models. An uncalibrated QUAL-TX model is normally used to evaluate streams and rivers upstream of the normal pool elevation of the reservoir. However, other suitable models may also be used. If the model predicts that there would be significant levels of oxygen-demanding pollutants remaining in the stream as it enters the impoundment, then some portion of the impoundment is evaluated. Discharges into small coves may be modeled using a CSTR model or other suitable technique.

Critical Low-Flow Values for East and South Texas Streams As specified in § 307.7(b)(3)(A)(ii) of the Standards, streams with limited, intermediate, high, or exceptional aquatic life uses and those listed in Appendix A or D of the Standards in the eastern and southern portions of the state may be evaluated for 24-hour dissolved oxygen attainment at stream flows greater than 7Q2 flows as presented in Table 4 on page 90. Flows in Table 4 apply in the months April through October.

B A

Figure 3. Headwater flows for streams in area “A” may be adjusted based on Table 4

Table 4. Critical Low-Flow Values for Dissolved Oxygen for East and South Texas

Bedslope Critical Low-Flow (ft3/s) (m/km) DOa = 6.0 mg/L 5.0 mg/L 4.0 mg/L 3.0 mg/L b 0.1 — 18.3 3.0 0.5 b 0.2 — 7.7 1.3 0.2 0.3 28.6 4.7 0.8 0.1 0.4 20.0 3.3 0.5 0.1 0.5 15.2 2.5 0.4 0.1 0.6 12.1 2.0 0.3 0.1 0.7 10.0 1.6 0.3 0.0 0.8 8.4 1.4 0.2 0.0 0.9 7.3 1.2 0.2 0.0 1.0 6.4 1.0 0.2 0.0 1.1 5.7 0.9 0.2 0.0 1.2 5.1 0.8 0.1 0.0 1.3 4.6 0.8 0.1 0.0 1.4 4.2 0.7 0.1 0.0 1.5 3.9 0.6 0.1 0.0 1.6 3.6 0.6 0.1 0.0 1.7 3.3 0.5 0.1 0.0 1.8 3.1 0.5 0.1 0.0 2.1 2.5 0.4 0.1 0.0 2.4 2.2 0.4 0.1 0.0 Note: Flows in this table apply only to the months April through October. a Dissolved oxygen criteria apply as 24-hour averages at all stream flows at or above the indicated stream flow for each category. b Flows are beyond the observed data used in the regression equation.

Example: If the bedslope of the stream is 1.1 m/km, and the DO criterion is 5.0 mg/L, then the critical low-flow value is 0.9 ft3/s.

The critical low-flows in Table 4 apply to streams that occur in the portion of the state east of a line defined by Interstate Highway 35 and 35W from the Red River to the community of Moore in Frio County, and by U.S. Highway 57 from the community of Moore to the Rio Grande (area “A” in Figure 3 on page 89). The flows shown in Table 4 may be used to evaluate summertime 24-hour dissolved oxygen criteria (see Table 1 on page 16) for a presumed, designated, or assigned aquatic life use. Certain water bodies in the Cypress Creek Basin should be evaluated using the procedures in the section of this document entitled “Regression Equation for Establishing Critical Low-Flows for Specific Water Bodies in the Cypress Creek Basin” on page 92.

Regression Equation Relating Dissolved Oxygen, Flow, and Bedslope The flow values in Table 4 were derived from a multiple regression equation using data collected from the TCEQ’s study of least impacted streams (Texas Aquatic Ecoregion Project). Results of this study indicate a strong dependent relationship for average summertime dissolved oxygen concentrations and several hydrologic and physical stream characteristics—particularly stream flow and bedslope (stream gradient).

Stream flows and average dissolved oxygen concentrations were measured during steady-state conditions, and bedslopes were estimated from 1:24,000 scale USGS topographic maps. Approximately 72% of the variation in observed average dissolved oxygen concentrations in these minimally impacted streams is explained by the following regression equation:

DO  7.088  0.551 ln(Q  0.01)  0.686 ln( Bd )  k

where: DO = dissolved oxygen (mg/L) Q = flow (ft3/s) Bd = bedslope (m/km) k = 1.61 (constant for 50th percentile of tree canopy cover)

The coefficient of determination (r2) for this equation, adjusted for degrees of freedom, is 0.72 (p < 0.0001). This equation may be used to calculate headwater flows for bedslopes within the range of 0.1 m/km to 2.4 m/km. For streams that have bedslopes greater than 2.4 m/km, a bedslope of 2.4 m/km will be used. For streams that have bedslopes less than 0.1 m/km, a bedslope of 0.1 m/km will be used. The headwater flows are calculated for dissolved oxygen concentrations of 0.5 mg/L greater than the criteria obtained from Table 1.

Calculating Bedslope

Bedslopes are calculated from USGS 1:24,000 scale topographic maps for the portion of stream from the first contour line crossing the stream greater than one-half mile upstream of the point of discharge to the first contour line crossing the stream downstream beyond the estimated distance of discharge impact. The actual stream bedslope is calculated using the following equation:

( Eu  Ed ) Bd  D

where: Bd = bedslope (m/km) Eu = upstream elevation (m) Ed = downstream elevation (m) D= linear distance along the streambed between the two elevation contours (km)

(Note: the elevations and linear distance in the formula can be calculated in feet and then multiplied by 1,000 to convert to meters per kilometer.)

Guidelines for Adjusting the Regression Equation The critical low-flows in Table 4 may be adjusted based on site-specific data. The following guidelines should be followed in order to apply site- specific changes to the regression equation used to calculate the Table 4 flows:

• • Collect data on streams in areas that are unaffected by other point source discharges. Data can be collected upstream of a discharger’s outfall as long as it is outside the mixing zone or on an adjacent stream with similar hydrology, drainage basin size, land use, habitat availability, and canopy cover.
• • Collect data during all seasons for at least one year.
• • Site-specific flow, temperature, or hydraulic conditions that affect dissolved oxygen can also be used to adjust critical low-flows.
• • Site-specific changes in critical low-flows will have to be reviewed and approved by the TCEQ.
• • EPA will review any site-specific, critical low-flows that could affect permits or other regulatory actions that are subject to EPA approval.

Regression Equation for Establishing Critical Low-Flows in Specific Water Bodies in the Cypress Creek Basin DO criteria for the following water bodies are based on a regression equation that relates dissolved oxygen, temperature, flow, and watershed size:

• • Segments 0406, 0407, 0409, and 0410 as specified in § 307.10, Appendix A, of the Standards.
• • Harrison Bayou (in Segment 0401) and Black Cypress Bayou (Creek) upstream of Segment 0410 as specified in § 307.10, Appendix D, of the Standards.

Data to define the DO relationship with these physical and chemical characteristics were collected in the watershed of Black Cypress Bayou (Creek) from 1998 to 2005. About 95% of the variation in observed 24- hour average DO concentrations can be explained by the regression equation. 9 The procedures in this section should be used for these water bodies in lieu of the more general East Texas procedures discussed in the preceding sections.

The critical low-flows for the applicable instream DO concentrations (1.5 mg/L – 5 mg/L) in Tables 4a-4e (see pages 96-99) were derived in order to develop effluent limits that will meet the 24-hour DO criteria. Each table applies at the appropriate critical temperature for each water body. The flows in Tables 4a-4e are based on the following equation:

DO  12.61  0.309T  1.05 log(Q )  1.02 log(WS )

where: DO = dissolved oxygen criterion + 0.5 (mg/L) T = temperature (˚C) Q = flow (ft3/s) WS = watershed size (km2)

This equation may be used directly to calculate headwater flows for watershed sizes that fall between those included in the table. The equation and tables are applicable for watershed sizes within the range of 50 km2 to 1000 km2. For sites that have watershed sizes greater than 1000 km2, a watershed size of 1000 km2 will be used. For sites that have watershed sizes less than 50 km2, a watershed size of 50 km2 will be used. The headwater flows are calculated for DO concentrations of 0.5 mg/L greater

9 Crowe, Arthur L. and Charles W. Bayer. “A Biological, Physical, and Chemical Survey of a Least- Impacted Watershed : Black Cypress Bayou (Creek), Texas, 1998-2005, AS-197. Texas Commission on Environmental Quality, November 2005 (revised March 2008).

than the calculated criteria. The maximum flow measured during the study was 1,140 ft3/s; this is also the maximum flow to be used in DO modeling.

Water Bodies with a Dissolved Oxygen Impairment More comprehensive approaches to setting effluent limits based on water quality criteria are necessary when water bodies receiving the discharge are included on the § 303(d) List as having dissolved oxygen concentrations lower than the criterion. When evaluating discharges to water bodies with existing WLEs or TMDLs, effluent limits are based on the WLE or TMDL model, or report as applicable. WLEs assess the effects of point source waste loading on dissolved oxygen concentrations. TMDLs typically are comprehensive analyses that include both point and nonpoint sources of oxygen-demanding pollutants.

All water bodies contained on the § 303(d) List will be considered for TMDL development. Reviews of TPDES applications received before TMDL development may be conducted with the screening level methodologies discussed previously (see page 84).

For applications that are proposing a new or increased load of oxygen- demanding constituents into the watershed of water bodies on the § 303(d) list for depressed DO, the potential of the additional loading to negatively affect the listed portion of the water body is assessed. If the new or increased flow and resulting loadings of oxygen-demanding substances will cause or further contribute to the depressed DO conditions in the impaired water body, the discharge will not be allowed.

Table 4a. Critical Low-Flow Values for Dissolved Oxygen for Harrison Bayou, in Segment 0401. Drainage Critical Low-Flow (ft3/s) Area 5.0 4.0 3.0 2.0 1.5 (km2) DOa = mg/L mg/L mg/L mg/L mg/L 50 273 31 3.4 0.38 0.13 100 536 60 6.7 0.74 0.25 150 795 89 9.9 1.1 0.37 200 1051 117 13 1.5 0.49 250 1140 b 146 16 1.8 0.61 300 1140b 174 19 2.2 0.72 350 1140 b 202 23 2.5 0.84 400 1140b 230 26 2.9 0.96 450 1140 b 258 29 3.2 1.1 500 1140b 286 32 3.6 1.2 550 1140 b 313 35 3.9 1.3 600 1140b 341 38 4.2 1.4 650 1140 b 369 41 4.6 1.5 700 1140b 396 44 4.9 1.6 750 1140 b 424 47 5.3 1.8 800 1140b 451 50 5.6 1.9 850 1140 b 478 53 6.0 2.0 900 1140b 506 56 6.3 2.1 950 1140 b 533 59 6.6 2.2 1000 1140b 560 63 7.0 2.3 Note: Flows in this table apply at the critical summer temperature of 27.3˚C for Harrison Bayou. a Dissolved oxygen criteria apply as 24-hour averages at all stream flows at or above the indicated stream flow for each category. b Flows are beyond the observed data used in the regression equation. Use the highest flow observed (1140 ft3/s).

Example: If the drainage area of the stream is 550 km2, then the following headwater flows are included in the model to meet the corresponding DO criteria:

1140 ft3/s to meet 5 mg/L DO, 313 ft3/s to meet 4 mg/l DO, 35 ft3/s to meet 3 mg/L DO, 3.9 ft3/s to meet 2 mg/L DO, and 1.3 ft3/s to meet 1.5 mg/L DO.

Table 4b. Critical Low-Flow Values for Dissolved Oxygen for Black Bayou, Segment 0406. Drainage Critical Low-Flow (ft3/s) Area 5.0 4.0 3.0 2.0 1.5 (km2) DOa = mg/L mg/L mg/L mg/L mg/L 50 223 25 2.8 0.31 0.10 100 437 49 5.4 0.61 0.20 150 649 72 8.1 0.90 0.30 200 858 96 11 1.2 0.40 250 1065 119 13 1.5 0.49 300 1140b 142 16 1.8 0.59 350 1140 b 165 18 2.1 0.69 400 1140b 188 21 2.3 0.78 450 1140 b 210 23 2.6 0.88 500 1140b 233 26 2.9 0.97 550 1140 b 256 29 3.2 1.1 600 1140b 278 31 3.5 1.2 650 1140 b 301 34 3.7 1.3 700 1140b 323 36 4.0 1.3 750 1140 b 346 39 4.3 1.4 800 1140b 368 41 4.6 1.5 850 1140 b 390 44 4.9 1.6 900 1140b 413 46 5.1 1.7 950 1140 b 435 49 5.4 1.8 1000 1140b 457 51 5.7 1.9 Note: Flows in this table apply at the critical summer temperature of 27.0˚C for Segment 0406. a Dissolved oxygen criteria apply as 24-hour averages at all stream flows at or above the indicated stream flow for each category. b Flows are beyond the observed data used in the regression equation. Use the highest flow observed (1140 ft3/s).

Example: If the drainage area of the stream is 550 km2, then the following headwater flows are included in the model to meet the corresponding DO criteria:

1140 ft3/s to meet 5 mg/L DO, 256 ft3/s to meet 4 mg/l DO, 29 ft3/s to meet 3 mg/L DO, 3.2 ft3/s to meet 2 mg/L DO, and 1.1 ft3/s to meet 1.5 mg/L DO.

Table 4c. Critical Low-Flow Values for Dissolved Oxygen for James Bayou, Segment 0407. Drainage Critical Low-Flow (ft3/s) Area 5.0 4.0 3.0 2.0 1.5 (km2) DOa = mg/L mg/L mg/L mg/L mg/L 50 470 52 5.9 0.65 0.22 100 922 103 11 1.3 0.43 150 1140 b 153 17 1.9 0.63 200 1140b 202 23 2.5 0.84 250 1140 b 251 28 3.1 1.0 300 1140b 299 33 3.7 1.2 350 1140 b 347 39 4.3 1.4 400 1140b 395 44 4.9 1.6 450 1140 b 443 49 5.5 1.8 500 1140b 491 55 6.1 2.0 550 1140 b 539 60 6.7 2.2 600 1140b 586 65 7.3 2.4 650 1140 b 634 71 7.9 2.6 700 1140b 681 76 8.5 2.8 750 1140 b 728 81 9.1 3.0 800 1140b 775 87 9.7 3.2 850 1140 b 823 92 10 3.4 900 1140b 869 97 11 3.6 950 1140 b 916 102 11 3.8 1000 1140b 963 107 12 4.0 Note: Flows in this table apply at the critical summer temperature of 28.1˚C for Segment 0407. a Dissolved oxygen criteria apply as 24-hour averages at all stream flows at or above the indicated stream flow for each category. b Flows are beyond the observed data used in the regression equation. Use the highest flow observed (1140 ft3/s).

Example: If the drainage area of the stream is 550 km2, then the following headwater flows are included in the model to meet the corresponding DO criteria:

1140 ft3/s to meet 5 mg/L DO, 539 ft3/s to meet 4 mg/l DO, 60 ft3/s to meet 3 mg/L DO, 6.7 ft3/s to meet 2 mg/L DO, and 2.2 ft3/s to meet 1.5 mg/L DO.

Table 4d. Critical Low-Flow Values for Dissolved Oxygen for Little Cypress Creek (Bayou), Segment 0409. Drainage Critical Low-Flow (ft3/s) Area 5.0 4.0 3.0 2.0 1.5 (km2) DOa = mg/L mg/L mg/L mg/L mg/L 50 617 69 7.7 0.86 0.29 100 1140b 135 15 1.7 0.56 150 1140 b 200 22 2.5 0.83 200 1140b 265 30 3.3 1.1 250 1140 b 329 37 4.1 1.4 300 1140b 392 44 4.9 1.6 350 1140 b 456 51 5.7 1.9 400 1140b 519 58 6.5 2.2 450 1140 b 581 65 7.2 2.4 500 1140b 644 72 8.0 2.7 550 1140 b 707 79 8.8 2.9 600 1140b 769 86 9.6 3.2 650 1140 b 831 93 10 3.5 700 1140b 893 100 11 3.7 750 1140 b 955 107 12 4.0 800 1140b 1017 113 13 4.2 850 1140 b 1079 120 13 4.5 900 1140b 1140 127 14 4.7 950 1140 b 1140 b 134 15 5.0 1000 1140b 1140b 141 16 5.3 Note: Flows in this table apply at the critical summer temperature of 28.5˚C for Segment 0409. a Dissolved oxygen criteria apply as 24-hour averages at all stream flows at or above the indicated stream flow for each category. b Flows are beyond the observed data used in the regression equation. Use the highest flow observed (1140 ft3/s).

Example: If the drainage area of the stream is 550 km2, then the following headwater flows are included in the model to meet the corresponding DO criteria:

1140 ft3/s to meet 5 mg/L DO, 707 ft3/s to meet 4 mg/l DO, 79 ft3/s to meet 3 mg/L DO, 8.8 ft3/s to meet 2 mg/L DO, and 2.9 ft3/s to meet 1.5 mg/L DO.

Table 4e. Critical Low-Flow Values for Dissolved Oxygen for Black Cypress Bayou (Creek), Segment 0410 and Black Cypress Bayou (Creek) upstream of Segment 0410. Drainage Critical Low-Flow (ft3/s) Area 5.0 4.0 3.0 2.0 1.5 (km2) DOa = mg/L mg/L mg/L mg/L mg/L 50 503 56 6.3 0.70 0.23 100 986 110 12 1.4 0.46 150 1140 b 163 18 2.0 0.68 200 1140b 216 24 2.7 0.90 250 1140 b 268 30 3.3 1.1 300 1140b 320 36 4.0 1.3 350 1140 b 372 41 4.6 1.5 400 1140b 423 47 5.3 1.8 450 1140 b 475 53 5.9 2.0 500 1140b 526 59 6.5 2.2 550 1140 b 577 64 7.2 2.4 600 1140b 628 70 7.8 2.6 650 1140 b 678 76 8.4 2.8 700 1140b 729 81 9.1 3.0 750 1140 b 779 87 9.7 3.2 800 1140b 830 93 10 3.5 850 1140 b 880 98 11 3.7 900 1140b 930 104 12 3.9 950 1140 b 981 109 12 4.1 1000 1140b 1031 115 13 4.3 Note: Flows in this table apply at the critical summer temperature of 28.2˚C for Segment 0410. a Dissolved oxygen criteria apply as 24-hour averages at all stream flows at or above the indicated stream flow for each category. b Flows are beyond the observed data used in the regression equation. Use the highest flow observed (1140 ft3/s).

Example: If the drainage area of the stream is 550 km2, then the following headwater flows are included in the model to meet the corresponding DO criteria:

1140 ft3/s to meet 5 mg/L DO, 577 ft3/s to meet 4 mg/l DO, 64 ft3/s to meet 3 mg/L DO, 7.2 ft3/s to meet 2 mg/L DO, and 2.4 ft3/s to meet 1.5 mg/L DO.

Memorandum of Agreement between the Texas Natural Resource Conservation Commission and the Environmental Protection Agency - Region 6 for

Application of Uncalibrated Water Quality Modeling for Texas Freshwater Streams The purpose of this Memorandum of Agreement (MOA) is to streamline the processes associated with the review and approval of individual permit waste load allocations (WLAs), water quality management plans (WQMPs), and Texas Pollutant Discharge Elimination System (TPDES) permits while assuring technical acceptability and consistency with the Clean Water Act (CWA).

The Environmental Protection Agency (EPA), Region 6, Water Quality Protection Division and the Texas Natural Resource Conservation Commission (TNRCC), Office of Permitting, Remediation & Registration agree to the following provisions:

1. WLAs for facilities included in a WQMP update with discharge flows less than or equal to 0.2 million gallons per day (MGD), which are developed using uncalibrated QUAL-TX modeling, where appropriate, with the reaction rates outlined below in Number 2, will be considered technically acceptable without EPA Region 6 review. The EPA Region 6 may review these WLAs during the semi-annual evaluations for the Section 106 State Water Pollution Control Program Grant.

2. The TNRCC will use the following reaction rates (expressed at 20ºC) when performing uncalibrated QUAL-TX modeling in freshwater streams:

a. CBOD decay rate: Kd = 0.10/day; and CBOD settling rate: Ks = 0.0 m/day

b. Ammonia-Nitrogen oxidation rate: Kn = 0.30/day

c. Sediment Oxygen Demand: SOD = 0.35 g/m2/day

d. Reaeration Rate: K2 will be calculated from equations contained in “Rates, Constants, and Kinetics Formulations in Surface Water Quality Modeling (Second Edition) June 1985, EPA/600/3-85/040.” The equation(s) will be chosen consistent with the hydraulic character of the stream and the following minimum and maximum constraints will apply; 0.6/depth(m)≤ K2≤10/day.

3. The level of algae specified in the model will be set to zero except in cases where site- specific measurements demonstrate appropriate minimum levels.

Memorandum of Agreement Page 2

4. This agreement does not apply to WLAs for dischargers in the following segments: 1001, 1005, 1006, 1007, 2426, 2427, 2428, 2429, 2430 and 2436.

5. Treatment limits developed from calibrated models and those contained in approved Waste Load Evaluations and Total Daily Maximum Load (TMDL) reports or implementation plans will supersede those derived from this methodology.

6. All remaining WLAs (>0.2 MGD) will be submitted for EPA technical review and approval. The EPA will provide a response to these submittals to the TNRCC within 30 days of receipt of modeling documentation. If a response is not received within 30 days, the WLA will be considered approved as submitted and TPDES permits can be issued without a formal approval on these WLAs from the EPA.

7. The EPA Region 6 will approve WQMP updates for WLAs prepared in accordance with this MOA after the WQMP updates have undergone public participation in accordance with 40 Code of Federal Regulations 25 and are certified by the TNRCC.

8. This MOA may be revised upon mutual consent of the TNRCC and the EPA.

9. The provisions of this MOA will apply to all domestic TPDES applications that are administratively complete on or after the effective date of the “Procedures to Implement the Texas Surface Water Quality Standards” which incorporates these modeling parameters. Prior to this date, the EPA will conditionally or fully approve WLAs submitted that were developed with the existing TNRCC Streeter-Phelps modeling protocols unless pollutants in the effluent from those facilities could cause or contribute to pollutants of concern on 303(d) listed streams.

We agree with the provisions outlined in this MOA and commit our agency to implement them in a spirit of cooperation and mutual support.

Whole Effluent Toxicity Testing (Biomonitoring)

Applicability Whole effluent toxicity (WET) testing, also known as biomonitoring, is required in permits for dischargers whose effluent has a significant potential to exert toxicity in the receiving water (See § 307.6(e)(2)(A) of the Standards). WET testing directly measures a discharge’s aggregate toxic effect by exposing surrogate sensitive test species to effluent at the critical dilution of the receiving water. Thus, it is an integral tool in the assessment of water quality for the protection of aquatic life and part of EPA’s integrated strategy that includes the use of three control approaches (the other two being chemical-specific limits and biological criteria).

Domestic Dischargers The TCEQ requires WET testing of domestic wastewater dischargers that have either or both of the following conditions:

• • classification as an EPA major domestic discharger (a design flow of 1 MGD or greater or an interim or final phase design flow of 1 MGD or greater); or • any individual WWTP with an approved pretreatment program with significant industrial users discharging into its collection system.

Permittees with more than one flow phase in their permit begin WET testing upon expansion to 1 MGD or greater.

Industrial Dischargers The TCEQ requires WET testing of industrial dischargers that have any of the following conditions:

• • classification as an EPA major industrial discharger; • a continuous discharge of process treated wastewater; or • a discharge with the potential to exert toxicity in the receiving water.

Although the TCEQ generally does not require WET testing of EPA- classified minor industrial dischargers, the TCEQ may require WET testing of such discharges in any of the following situations:

• • the permittee applies water treatment chemicals or biocides;

• • the TCEQ determines that the effluent has the potential to exert toxicity in the receiving water; or
• • the permit requires effluent limits based on aquatic life water quality criteria because the effluent analysis exceeds the screening criteria.

Chapter Outline The rest of this chapter covers the following topics:

• • types of WET tests (chronic and 48-hour acute—page 104; 24-hour acute—page 118)
• • test acceptability criteria (chronic and 48-hour acute—page 105; 24- hour acute—page 119)
• • statistical interpretation of test results (chronic and 48-hour acute only―page 107)
• • test frequencies (chronic and 48-hour acute—page 108; 24-hour acute—page 119)
• • dilution series, dilution water, and type of WET tests—page 110
• • reasonable potential determination (chronic and 48-hour acute only―page 113)
• • toxicity reduction evaluations (chronic and 48-hour acute—page 115; 24-hour acute—page 121)
• • toxicity control measures (chronic and 48-hour acute—page 116; 24- hour acute—page 122)
• • toxicity caused by some specific pollutants—dissolved salts (page 122), ammonia (page 128), and Diazinon (page 129).

Chronic and 48-Hour Acute Tests The TCEQ may require permittees to conduct 7-day chronic or 48-hour acute WET tests to measure compliance with the requirements of § 307.6(e) of the Standards. Toxicity in these tests is defined as a statistically significant difference (usually at the 95% confidence level) between the survival, reproduction, or growth of the test organisms at a specified effluent dilution (the critical dilution) compared to the survival, reproduction, or growth of the test organisms in the control (0% effluent).

Test Types The permit will specify that tests be conducted using the latest version of the appropriate EPA method. These methods can be found in the following publications (or their most recent versions):

• • Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, Fourth Edition, EPA- 821-R-02-013, October 2002.
• • Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, Third Edition, EPA-821-R-02-014, October 2002.
• • Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition, EPA- 821-R-02-012, October 2002.

In addition, information on interpreting non-monotonic test results and percent minimum significant difference (PMSD) values can be found in the following publications:

• • Understanding and Accounting for Method Variability in Whole Effluent Toxicity Applications Under the National Pollutant Discharge Elimination System Program, EPA 833-R-00-003, June 2000.
• • Method Guidance and Recommendations for Whole Effluent Toxicity (WET) Testing (40 CFR Part 136), EPA 821-R-B-00-004, July 2000.

The permittee must use a revised promulgated method if one becomes available during the term of the permit. Alternate test methods are subject to EPA review and approval. Depending on the type of receiving water, the permit will specify chronic or 48-hour acute tests to assess toxicity to freshwater or saltwater organisms. The test organisms used for each type of test are listed below.

FRESHWATER STREAMS AND LAKES (SALINITY < 2 PPT)

CHRONIC 3-brood Ceriodaphnia dubia (water flea) survival and reproduction test 7-day Pimephales promelas (fathead minnow) larval survival and growth test

ACUTE 48-hour Daphnia pulex or Ceriodaphnia dubia (water fleas) survival test 48-hour Pimephales promelas (fathead minnow) survival test

MARINE RECEIVING WATER (SALINITY ≥ 2 PPT)

CHRONIC 7-day Americamysis bahia (mysid shrimp, formerly Mysidopsis bahia) survival and growth test 7-day Menidia beryllina (inland silverside) larval survival and growth test

ACUTE 48-hour Americamysis bahia (mysid shrimp) survival test 48-hour Menidia beryllina (inland silverside) survival test

Permittees may substitute other EPA approved tests and species if they obtain approval from the TCEQ during the permit application process (see the sections of this document entitled “Toxicity Attributable to Dissolved Salts” on page 122 and “Site-Specific Standards for Total Toxicity” on page 207).

Typically, if the segment criterion for total dissolved solids (TDS) or the site-specific TDS concentration in the receiving water is too high to support Ceriodaphnia dubia or Daphnia pulex, Daphnia magna (another water flea) will be substituted as the invertebrate freshwater test organism after the need to make the substitution is demonstrated. The permittee may submit evidence substantiating the need for an alternative species before or during the application process. However, draft permits with alternate tests, alternate species, or testing requirements that exclude a species are subject to EPA review and approval.

Test Acceptability Criteria A toxicity test that fails to meet any of the following acceptability criteria is considered invalid, and the permittee will have to repeat the test. Other factors may also invalidate a test. All test results, valid or invalid, are to be submitted to the TCEQ.

Chronic Freshwater • a mean survival of 80% or greater in the control.

• • a mean number of 15 or greater water flea neonates per surviving adult in the control.
• • a mean dry weight of 0.25 mg or greater for surviving fathead minnow larvae in the control.
• • a coefficient of variation percent (CV%) of 40 or less between replicates in the control and in the critical dilution for:

◦ the young of surviving females in the water flea reproduction and survival test; and ◦ the growth and survival endpoints in the fathead minnow growth and survival test.

However, if statistically significant lethal or sublethal effects are exhibited , a CV% greater than 40 does not invalidate the test.

• • a PMSD of 47 or less for the water flea and a PMSD of 30 or less for the fathead minnow. However, if statistically significant sublethal effects are exhibited, a PMSD in excess of that specified above does not invalidate the test.
• • a test population of < 20% males in a single concentration or < 20% males in a whole test for the water flea reproduction test.

Chronic Saltwater • a mean survival of 80% or greater in the control.

• • a mean dry weight of 0.20 mg or greater for surviving mysid shrimp in the control.
• • a mean dry weight in the control of 0.50 mg or greater for surviving unpreserved inland silverside and 0.43 mg or greater for surviving preserved inland silverside.
• • a CV% of 40 or less in the control and in the critical dilution in the growth and survival tests. However, if statistically significant lethal or sublethal effects are exhibited, a CV% greater than 40 does not invalidate the test.

• • a PMSD of 37 or less for the mysid shrimp and a PMSD of 28 or less for the inland silverside. However, if statistically significant sublethal effects are exhibited, a PMSD in excess of that specified above does not invalidate the test.

48-hour Acute Freshwater and Saltwater • a mean survival of 90% or greater in the control.

• • a CV% of 40 or less in the control and in the critical dilution.

However, if significant lethality is demonstrated, a CV% greater than 40 does not invalidate the test.

Once-Through Cooling Water Facilities Once-through cooling water facilities that use intake water as the control do not have to retest and report a valid test for each test species during the reporting period if the test is invalid because the control fails to meet acceptability criteria. This exception recognizes that running additional tests is not useful when the source waterbody itself is already toxic to one or both test organisms due to total dissolved solids (TDS), pathogenic bacteria, or toxic algae blooms.

Statistical Interpretation of Test Results If significant lethality is demonstrated (that is, if there is a statistically significant difference in survival at the critical dilution when compared to the control), but the conditions of test acceptability are met and the survival endpoint equals or exceeds the acceptability criteria at the critical dilution and all dilutions below that, then the permittee may report a survival NOEC of not less than the critical dilution.

While the nominal error rate (alpha) used for hypothesis testing in WET data is 0.05 (95% confidence interval), the alpha level for sublethal statistical analysis may be modified in accordance with EPA guidelines under appropriate conditions. 10

While the method manuals list a range for PMSDs, a value below that range does not invalidate the test. If no significant sublethal effects are indicated, the NOEC should be reported as is. However, if the test indicates statistically significant sublethal effects, additional calculations should be performed in order to determine the NOEC. 11

10 Method Guidance and Recommendations for Whole effluent Toxicity (WET) Testing (40 CFR Part 136), EPA 821-B-00-004, July 2000. 11 Understanding and Accounting for Method Variability in Whole Effluent Toxicity Applications Under the National Pollutant Discharge Elimination System Program, EPA 833-R-00-003, June 2000.

Test Frequencies

General Figure 4 on page 109 illustrates the chronic and 48-hour acute testing frequencies for facilities with WET requirements. Testing is typically performed quarterly for both the vertebrate and the invertebrate test species for the first year of the permit term. EPA requires quarterly testing for at least one year to assess the variability and toxic potential of effluents.

If no significant effects are demonstrated in the first year of quarterly testing, the permittee may request a testing frequency reduction to once per six months for the invertebrate and once per year for the vertebrate for the remainder of the permit term.

Initial After passing four Pass all lethal consecutive tests with no YES quarterly and sublethal lethal or sublethal failures, testing tests? permittee may request a reduced testing frequency. NO

Lethal failure— Sublethal two monthly NO failure only retests (not a lethal failure)?

YES Continue or resume quarterly testing until four Two monthly consecutive tests show no retests lethal or sublethal effects.

Did one or YES both tests Did both pass? tests pass?

YES NO

NO Continue or resume quarterly testing.

TRE recommended

Figure 4. Chronic and 48-Hour WET Testing Frequencies

If significant lethality is demonstrated in the first year of quarterly testing, that species is not eligible for the testing frequency reduction and the permittee must then test quarterly for the permit term. If significant sublethality is demonstrated in the first year of quarterly testing, the permittee will not be eligible for the testing frequency reduction for that species until no significant effects are demonstrated for four consecutive quarterly tests.

If a testing frequency reduction has been granted for a species, but that species subsequently demonstrates significant lethality, the quarterly testing frequency for that species will be resumed for the permit term. If a testing frequency reduction has been granted for a species, but that species subsequently demonstrates significant sublethality, the quarterly testing frequency for that species will be resumed until four consecutive quarterly tests demonstrate no significant effects.

With a WET Limit Permittees will be required to perform quarterly testing for at least three years when a WET limit is added to the permit. This frequency only applies to the species with the WET limit. Best professional judgment (BPJ) will be used to establish testing frequencies when a chemical- specific limit or best management practice (BMP) is placed in the permit to control effluent toxicity.

Dilution Series, Dilution Water, and Type of WET Test

Dilution Series Chronic and some 48-hour acute tests are based on the critical dilution in the receiving water. The critical dilution represents the percentage of effluent at the edge of the mixing zone during critical low-flow (that is, the 7Q2 or appropriate critical low-flow for spring-fed streams) or critical mixing conditions. Some 48-hour acute tests are based on the percentage of effluent at the edge of the zone of initial dilution (ZID). The test results at the critical dilution are statistically compared with the test results at the control dilution (0% effluent) to measure compliance. The permit specifies the critical dilution and the dilution series as well as the type of WET tests required.

The dilution series consists of four effluent concentrations in addition to the critical dilution. For domestic dischargers, the design flow is normally used to calculate the critical dilution. For industrial dischargers who are renewing permits, the highest monthly average flow from the preceding two years is normally used to calculate the critical dilution. For new or expanding industrial facilities, the design flow is used to calculate the critical dilution.

Dilution Water As specified in the permit, receiving water unaffected by the discharge should be used as the control and as dilution water for at least the first series of WET tests performed after a new permit is issued.

If the receiving water demonstrates pre-existing instream toxicity (by failing to meet the appropriate test acceptability criteria in the control), the test is considered invalid, and a repeat test has to be performed unless a “performance control” using synthetic dilution water was run at the same time and no toxic effects were demonstrated.

Upon demonstrating that the receiving water is toxic, the permittee may substitute synthetic dilution water for receiving water as the control and as dilution water in all subsequent tests for that permit term. The physical and chemical properties (for example, pH, hardness, TSS, alkalinity) of the synthetic dilution water should be similar to those of the receiving water.

Type of Test The TCEQ determines what type of WET test (freshwater or marine, acute or chronic) to place in the permit based on the salinity and critical conditions of the receiving waters. In general, TCEQ staff considers salinities at or above 2,000 mg/L (2.0 ppt) to represent saltwater conditions.

If the TCEQ determines that WET testing is required for a storm water discharge, TCEQ staff may use an analysis of the watershed to determine runoff volumes for dilution estimates. In addition, the TCEQ may require WET testing or other methods to protect water bodies with endangered species.

INTERMITTENT STREAMS WITH MINIMAL AQUATIC LIFE USE Permittees that discharge into intermittent streams with a minimal aquatic life use will conduct 48-hour acute testing with a critical dilution of 100% effluent.

INTERMITTENT STREAMS WITH PERENNIAL POOLS Permittees that discharge into intermittent streams with perennial pools will conduct chronic testing with a critical dilution of 100% effluent.

INTERMITTENT STREAMS WITH SEASONAL AQUATIC LIFE USES TCEQ may require dischargers to conduct chronic testing to protect intermittent streams that may have seasonal aquatic life uses. TCEQ determines the critical dilution from the typical flows in the season in which the use occurs.

INTERMITTENT STREAMS WITHIN THREE MILES OF A PERENNIAL FRESHWATER STREAM Permittees that discharge into intermittent streams that flow into a perennial stream within a moderate distance downstream (normally 3 miles) will conduct either a 48-hour acute or a chronic test. The type of test depends on the size of the discharge relative to the flow of the perennial water downstream.

If the effluent flow equals or exceeds 10% of the low-flow of the perennial water, the permittee will conduct chronic testing with a critical dilution representative of the percentage of effluent in the perennial stream during low-flow. If the effluent flow is less than 10% of the low-flow in the perennial stream, the permittee will conduct 48-hour acute toxicity tests with a critical dilution of 100% effluent. The TCEQ generally requires permittees that discharge into intermittent streams within 3 miles of a bay, estuary, or tidal river to conduct chronic marine testing.

PERENNIAL FRESHWATER STREAMS Permittees that discharge directly into perennial freshwater streams or rivers with a designated or limited, intermediate, high, or exceptional aquatic life use will conduct chronic testing; the critical dilution will be based on the effluent flow and critical low-flow of the stream or river. If the critical dilution is less than 5%, the TCEQ requires 48-hour acute testing and uses an acute-to-chronic ratio (ACR) of 10:1 to determine the appropriate critical dilution. The ACR is the ratio of the acute toxicity of an effluent or toxicant to its chronic toxicity. It is used to estimate the chronic toxicity based on acute toxicity results. An ACR of 10 represents the upper 90th percentile of the ACR data available to EPA in 1991.

LAKES Permittees that discharge to a lake will normally conduct chronic WET tests with a critical dilution of 15% if the effluent flow is less than or equal to 10 MGD and the mixing zone is 100 feet wide. If the effluent flow is greater than 10 MGD or if the mixing zone is less than 100 feet wide, the TCEQ typically uses the horizontal Jet Plume equation (see page 74) to determine the percentage of effluent at the edge of the mixing zone. In these cases the critical dilution is generally greater than 15%. The TCEQ assigns a critical dilution of 100% effluent for discharges greater than 100 MGD.

BAYS, ESTUARIES, AND WIDE TIDAL RIVERS Permittees that discharge into bays, estuaries, and wide tidal rivers (≥ 400 feet across) will normally conduct chronic WET tests with a critical dilution of 8% if the effluent flow is less than or equal to 10 MGD. If the effluent flow is greater than 10 MGD, the TCEQ uses the horizontal Jet Plume equation (see page 74) to determine the percentage of effluent at the edge of the mixing zone. The TCEQ assigns a critical dilution of 100% effluent for discharges greater than 100 MGD.

NARROW TIDAL RIVERS Permittees that discharge into narrow tidal rivers (< 400 feet across) will normally conduct chronic WET tests with the critical dilution based on upstream flow whenever flow information is available. In the absence of site-specific data such as dispersion dye studies or nearby flow measurements, the critical dilution typically is not less than 8% to ensure the same level of protection given to other marine waters. If upstream flows are not available, the horizontal Jet Plume equation (see page 74) is used to determine the critical dilution at the edge of the mixing zone. Critical dilutions calculated in this way are greater than 8% because the mixing zone size is less than 200 feet.

Diffusers An effluent diffuser installed at the end of a discharge pipe may increase mixing and lower critical dilutions. See the section of this document entitled “Diffusers” on page 82 for more information. The effluent percentage at the edge of the mixing zone for a diffuser discharge is usually determined through modeling. This effluent percentage, if determined to be appropriate, is normally used as the critical dilution for chronic WET testing. If the critical dilution is less than 5%, the TCEQ may instead require 48-hour acute testing using an ACR of 10:1 to determine the appropriate critical dilution.

Reasonable Potential Determination Permit applications that meet the applicability criteria for WET testing will be screened to determine if the discharge has a reasonable potential (RP) to cause significant toxicity. A reasonable potential analysis is performed in order to determine whether an effluent can reasonably be expected to cause or contribute to an exceedance of a state water quality standard or criterion within that standard.

For renewed or amended permit applications, screening for RP will be based on representative data from the previous five years of WET testing. New permit applications will not be screened for RP, since there will be no data from previous WET testing. Toxicity for new permits will be assessed by routine, periodic WET testing after the permits are issued.

Toxicity is presumed if a test fails for the lethal or sublethal endpoint. A test is considered to have failed if a statistically significant difference occurs between the control and the critical dilution.

In accordance with federal regulations, the TCEQ will make an RP determination for toxicity. The determination will be based on best professional judgment as well as additional factors, such as duration and magnitude, as agreed upon by the TCEQ and the EPA. Each test species will be evaluated separately.

When a final determination of RP is made, the permit will be issued for a five-year term, including an initial one-year investigative period for the permittee to conduct an initial toxicity investigation. The investigative period will be followed by up to a three-year compliance period to allow for assessment of the cause and/or elimination of toxicity prior to the effective date of the WET limit.

If appropriate, the permittee may apply for a permit amendment to remove the WET limit by replacing it with a chemical-specific limit or a best management practice (BMP) prior to the end of the compliance period (see below). If there are no further demonstrations of toxicity during the compliance period, the WET limit will not become effective. If the WET limit does become effective, the permittee may, after three years of compliance, submit a major amendment application to request removal of the WET limit and resumption of routine WET testing.

Addressing WET Limit Violations If the permittee fails a WET test (that is, demonstrates significant toxicity at the critical dilution) while the limit is in effect, the testing frequency for the species increases to monthly until the permittee passes (does not demonstrate significant toxicity at the critical dilution) three consecutive tests, after which the permittee may resume quarterly testing.

However, if the permittee fails two tests during the increased monthly testing period, the permittee will be considered noncompliant with the WET limit, will receive a Notice of Enforcement (NOE), and will be referred to TCEQ’s Enforcement Division for formal enforcement action. This process is illustrated in Figure 5 on page 117.

Chemical-Specific Limit In order to be eligible for a chemical-specific limit in lieu of a WET limit, the permittee has to demonstrate that one or more known pollutants caused the toxicity and should attempt to determine a specific concentration of the pollutant that will not cause toxicity. A chemical-specific limit may be inadequate to address toxicity in the following situations:

• • failure to identify the toxicant or toxicants. • presence of multiple toxicants. • lack of a routine test method capable of detecting a pollutant at levels causing persistent significant toxicity.

BMP In terms of WET testing, BMPs are defined as a practice or combination of practices that remove toxicity from the effluent by eliminating the source of toxicity. In order to be eligible for a BMP in lieu of a WET limit, the permittee has to demonstrate that such a provision can adequately address toxicity. If successful, the BMP becomes an enforceable part of the permit. A BMP does not include making changes to operations or housekeeping practices to reduce toxicity. In these cases, the source of toxicity still remains.

Toxicity Reduction Evaluations (TREs)

When is a TRE Performed? The TCEQ suggests that a permittee initiate a TRE when persistent significant toxicity occurs during routine WET testing. A TRE may allow the permittee to avoid a WET limit as the toxicity control measure.

If a permittee fails a WET test, that is, statistically significant toxicity occurs at the critical dilution, the permittee will conduct two retests with that test species. The retests are to be conducted monthly during the next two consecutive months. If persistent significant toxicity is demonstrated by failure of one or both retests, the permittee may wish to perform a TRE. A second retest is not required if the first retest confirms persistent toxicity.

TRE Purpose and Content The purpose of the TRE is to determine the cause and source of toxicity, and to determine methods to reduce or eliminate the toxicity. Components of a TRE may include, but are not limited to:

• • chemical analyses • effluent characterization tests (physical/chemical properties) • WET tests on effluent before and after characterization test manipulations • WET tests on effluent after chemical/physical separations • source identification evaluation or toxicity source evaluation • instream WET tests • chemical identification after chemical/physical separations of toxic phase • assessment of treatment technology available to remove the toxic substance from the effluent.

For more information on methods used in TREs, see the following documents (or their most recent versions):

• • Toxicity Identification Evaluation: Characterization of Chronically Toxic Effluents, Phase I, EPA/600/6-91/005F, May 1992.
• • Methods for Aquatic Toxicity Identification Evaluations: Phase I Toxicity Characterization Procedures, Second Edition, EPA/600/6- 91/003, February 1991.
• • Methods for Aquatic Toxicity Identification Evaluations: Phase II Toxicity Identification Procedures for Samples Exhibiting Acute and Chronic Toxicity, EPA/600/R-92/080, September 1993.
• • Methods for Aquatic Toxicity Identification Evaluations: Phase III Toxicity Confirmation Procedures for Samples Exhibiting Acute and Chronic Toxicity, EPA/600/R-92/081, September 1993.

Permittee performing quarterly testing under a WET limit

Initial test failure

Two additional test failures Increase test frequency to monthly during period of Pass for species that failed test. increased test frequency

Noncompliance with WET limit has been demonstrated:

NOE and Mandatory Enforcement

Permittee continues monthly testing until 3 consecutive tests are passed.

Return to quarterly testing

Figure 5. Procedure for Addressing WET Limit Violations

24-Hour Acute (100% End-of-Pipe) Tests In addition to conducting chronic or 48-hour acute tests, dischargers are required to conduct 24-hour acute tests using 100% effluent. This end-of- pipe test measures compliance with § 307.6(e)(2)(B) of the Standards, which requires that greater than 50% of the test organisms survive exposure to 100% effluent for 24 hours. This provision is designed to ensure that water in the state will not be acutely toxic to aquatic life passing through the ZID.

In addition to facilities mentioned previously in the section “Applicability” (see page 102), the TCEQ may require 24-hour acute testing for intermittent process water outfalls and/or storm water outfalls with the potential for causing toxicity. Dischargers with multiple outfalls will test each outfall that has the potential to cause toxicity. Multiple outfall samples may not be composited for this test.

Test Types The permit will specify that the tests be conducted using the latest version of the appropriate EPA method. The 24-hour acute test species and methods are the same as those for 48-hour acute testing and can be found in the manual listed on page 104. Depending on the type of receiving water, the permit will specify 24-hour acute tests to assess toxicity to freshwater or saltwater organisms. The test organisms for each type of test are as follows:

Freshwater streams and lakes (salinity < 2 ppt): • 24-hour Daphnia pulex or Ceriodaphnia dubia (water fleas) survival test • 24-hour Pimephales promelas (fathead minnow) survival test

Marine receiving water (salinity ≥ 2 ppt): • 24-hour Americamysis bahia (mysid shrimp) survival test • 24-hour Menidia beryllina (inland silverside) survival test

Permittees may substitute other EPA-approved tests and species if they obtain approval from the TCEQ before or during the permit application process (see the sections in this document entitled “Toxicity Attributable to Dissolved Salts” on page 122 and “Site-Specific Standards for Total Toxicity” on page 207).

Typically, if the segment TDS criterion or site-specific TDS concentration in the receiving water is too high to support Ceriodaphnia dubia or Daphnia pulex, Daphnia magna (water flea) is substituted as the invertebrate test organism. However, draft permits with alternate tests, alternate species, or testing requirements that exclude a species are subject to EPA review and approval.

Test Acceptability Criterion The permittee will have to repeat any toxicity test if the mean survival of the control is less than 90%. Any toxicity test that fails to meet the acceptability criterion is considered invalid.

Test Frequencies The standard frequency for 24-hour acute WET testing is once per six months unless otherwise specified.

Toxicity Reduction Evaluations (TREs) Failing a 24-hour acute WET test (demonstrating 50% or greater mortality) necessitates two retests over consecutive weeks (unless retesting concurrently with chronic test failure; in such a case, the permittee may defer to the chronic monthly retest schedule). If both retests pass (demonstrate greater than 50% survival), the permittee continues testing at the original frequency designated in the permit.

If one or both of the retests fail, the permittee has demonstrated persistent significant mortality, and the permittee is required to perform a TRE. From the date that persistent mortality is confirmed, the permittee has three years to comply with 30 TAC § 307.6(e)(2)(B) of the Standards.

TRE Purpose and Content The purpose of the TRE is to determine the cause and source of toxicity, and to determine methods to reduce or eliminate the toxicity. Components of a TRE are the same as described in the chronic/48-hour acute section.

TRE Plan The permit requires the discharger to submit a general outline for performing a TRE within 45 days of the retest that confirms persistent mortality. The outline should describe the preparations the permittee will take to develop and implement a TRE.

Within 90 days of the retest that confirms persistent mortality, the permit requires the discharger to submit a detailed TRE plan. The TRE plan should describe the specific approach and methodology the permittee will use during the TRE and include schedules for chemical and biological testing, specific activities, a sampling plan, a quality assurance plan, and project organization. The TRE schedule and approach may be modified as necessary during the process.

Toxicity attributable to dissolved salts and ammonia are discussed in the sections of this document entitled:

• • “Toxicity Attributable to Dissolved Salts” (see page 122) • “Ammonia Toxicity” (see page 128)

Quarterly Reports The permittee must submit quarterly reports to TCEQ that describe TRE progress and results. The permit also requires the permittee to complete the TRE and submit a final report within 18 months of the retest that confirms lethality. Permittees may request an extension to the 18-month time limit. The extension, however, must be warranted, and approval is contingent upon permittees demonstrating (1) due diligence in pursuit of the TRE and (2) the existence of circumstances beyond their ability to control.

Ceasing a TRE Permittees may cease TRE activities if they demonstrate to the executive director that the effluent no longer causes significant mortality to the test organisms. The permit defines a cessation of significant mortality as no test failures for a period of 12 consecutive weeks with at least weekly testing. This permit language accommodates situations where operational errors and upsets, spills, or sampling errors triggered the TRE, in contrast to a situation where a single toxicant or group of toxicants cause lethality.

When a permittee ceases TRE activities under the cessation of significant mortality provision, that permittee continues WET testing as required in the permit. This provision is not applicable if the significant mortality ceases for 12 consecutive weeks as a result of the permittee taking corrective action. Corrective actions include source reduction or elimination, process changes, housekeeping improvements, changes in chemical use, and/or modification to wastewater treatment.

Toxicity Control Measures After the TRE, the TCEQ will amend the permit to include a chemical- specific (CS) limit, a best management practice (BMP), or a whole effluent toxicity (WET) limit.

If appropriate, the permittee may apply for a permit amendment to remove the WET limit by replacing it with a chemical-specific limit or a BMP prior to the end of the compliance period (see below). If there are no further demonstrations of mortality during the compliance period, the WET limit does not become effective. If the WET limit does become effective, the permittee may, after three years of compliance, submit a major amendment application to request removal of the WET limit and resumption of routine WET testing.

Chemical-Specific Limit In order to be eligible for a chemical-specific limit in lieu of a WET limit, the permittee has to demonstrate that one or more known pollutants caused the mortality and should attempt to determine a specific concentration of the pollutant that will not cause mortality. A chemical-specific limit may be inadequate to address mortality in the following situations:

• • failure to identify the toxicant or toxicants; • presence of multiple toxicants; or • lack of a routine test method capable of detecting a pollutant at levels causing persistent significant mortality.

BMP In terms of WET testing, BMPs are defined as a practice or combination of practices that remove toxicity from the effluent by eliminating the source of toxicity. In order to be eligible for a BMP in lieu of a WET limit, the permittee has to demonstrate that such a provision can adequately address mortality. If successful, the BMP becomes an enforceable part of the permit. A BMP does not include making changes to operations or housekeeping practices to reduce toxicity. In these cases, the source of toxicity still remains.

WET Limit Failure to identify the toxicant or toxicants, presence of multiple toxicants, or lack of a routine test method capable of detecting a pollutant at levels causing toxicity, are examples of cases where a CS limit or BMP may be inadequate to address toxicity. In such cases, where no other appropriate toxicity control measure has been identified, the permit will be amended to add a WET limit with a compliance period, if appropriate.

WET Limit Violations If the permittee fails a WET test while the limit is in effect, the testing frequency for the species increases to monthly until the permittee passes (does not demonstrate significant mortality) three consecutive tests, after which the permittee may resume the specified testing frequency.

Test Substitution The TCEQ normally requires permittees to conduct the chronic or 48-hour acute WET tests and the 24-hour acute (100% end-of-pipe) WET tests as separate permit requirements. If the chronic or 48-hour acute WET test includes a test of 100% effluent in the dilution series, the permit allows the results from that test (after 24 hours of exposure) to fulfill the requirements in the 24-hour acute tests. The permittees then report the survival of organisms in the 100% effluent concentrations after 24 hours.

The permit stipulates that the 24-hour acute WET testing provision applies whether the test results submitted are for this requirement, the 48-hour acute requirements, or the chronic requirements. The permittee may add a 100% effluent dilution to chronic or 48-hour acute tests and submit the results after 24 hours to fulfill the 24-hour acute testing requirements.

Toxicity Attributable to Dissolved Salts Permittees may be exempt from compliance with the total toxicity provisions in the Standards if they demonstrate that dissolved salts are causing the effluent to be toxic. This exemption is allowed under the definition of toxicity in the Standards and under the 24-hour, 100% end- of-pipe acute toxicity provisions (See § 307.6(e)(2)(B) of the Standards).

The definition of toxicity in the Standards excludes adverse effects caused by concentrations of dissolved salts when the salts originate in a permittee’s source water. This exemption would affect compliance with the chronic and 48-hour acute WET testing provisions.

According to § 307.3(a)(65) of the Standards, “Source water is defined as surface water or groundwater that is used as a public water supply or industrial water supply (including cooling water supply). Source water does not include brine water that is produced during the extraction of oil and gas, or other sources of brine water that are substantially uncharacteristic of surface waters in the area of the discharge.”

Also, dischargers that exhibit 24-hour acute toxicity caused by: (1) concentrations of dissolved salts that originate from the source water or (2) an excess, deficiency, or imbalance of dissolved salts in the effluent are exempted from compliance with the 24-hour, 100% end-of-pipe acute toxicity provision. These exemptions, which are specified in § 307.6(e)(2)(B) of the Standards, do not include instances where individually toxic components (for example, the pollutants listed in Table 1 of the Standards) have formed a salt compound that is causing the effluent to be toxic.

The following two sections further explain the exemptions for dissolved salts.

Chronic or 48-hour 24-hour acute acute retest failure retest failure

TRE TRE

Are dissolved salts No Are dissolved salts No a cause of toxicity? a cause of toxicity?

Yes Yes

Are dissolved salts No Are dissolved salts the primary cause of Continue TRE No the primary cause of toxicity? toxicity?

Yes Yes

Does the dissolved Are the dissolved No No salt contain a toxic component salts in the source such as those listed in Table 1 water? of the TSWQS?

Yes Yes

Cease the TRE and evaluate Receive permit limits Cease the TRE and evaluate the use of alternate test or control measures. the use of alternate test species species or test protocol. or an ion adjustment protocol.

Figure 6. Procedure for Exemption from Total Toxicity Requirements because of Dissolved Salts

TDS Exemption—24-Hour Acute (100% End-of-Pipe) Tests When a permittee believes failure of the 24-hour acute tests occurred because of dissolved salts and seeks an exemption for that demonstration of toxicity, the permittee will have to demonstrate that dissolved salts are a cause of toxicity in the effluent. Because the effluent may have multiple toxicants, the permittee then has to prove that dissolved salts are the primary cause of toxicity. The following paragraphs describe the process in more detail.

Are Dissolved Salts a Cause of Toxicity? To confirm that dissolved salts are a cause of toxicity in the effluent, the permittee is required to conduct at least one set of toxicity identification evaluation (TIE) characterization tests including an ion-exchange procedure.

• • If the TIE tests fail to prove that dissolved salts are a cause of toxicity, the permittee should continue with the TRE to identify the toxicant or toxicants and to reduce or eliminate the acute toxicity.
• • If the TIE tests show that dissolved salts are a cause of toxicity in the effluent, the permittee then has to prove that they are the primary cause of acute toxicity.

Are Dissolved Salts the Primary Cause of Toxicity? The permittee should use a combination of the following techniques to show that dissolved salts are the primary cause of acute toxicity:

• • conduct WET tests using an alternate species that is more tolerant of dissolved salts.
• • conduct side-by-side WET tests using the toxic effluent as well as a mock effluent formulated to mimic the ionic composition of the effluent.
• • perform measurements of high levels of dissolved salts in the effluent.
• • perform an analysis of the ionic components of the dissolved salts.
• • use computer models that predict the acute toxicity of saline waters.
• • perform WET tests using sea salts that are formulated to correct ionic imbalances.

The permittee may suggest other methods to demonstrate that dissolved salts are the primary cause of toxicity for the TCEQ’s review and consideration.

• • If these techniques show that dissolved salts are not the primary cause of acute toxicity, the permittee will continue with the TRE to address the toxicity.
• • If the techniques prove that dissolved salts are the primary cause of toxicity, the TRE requirements cease.

Evaluating the Use of an Alternative Test Species When the TRE ceases because dissolved salts are the primary source of acute toxicity, the TCEQ evaluates or requires the permittee to evaluate the use of an alternative test species or modified test protocol.

The permittee may be required to continue conducting the 24-hour acute tests if an alternate test protocol successfully resolves the acute toxicity caused by the dissolved salts in the effluent. The TCEQ then initiates an amendment of the permit to include these measures.

If an alternate species is unavailable, or if test protocol modifications such as ionic adjustments are unsuccessful, the permittee will most likely be required to continue testing with the standard test species that is unaffected by the dissolved salts.

TDS Exemption—Chronic and 48-Hour Acute Tests When a permittee believes effluent toxicity evidenced by a chronic or 48- hour acute WET test is caused by dissolved salts and seeks an exemption for that demonstration of toxicity, the permittee should follow an approach similar to that described in the previous subsection. EPA will review any protocol that could affect permits or other regulatory actions that are subject to EPA approval.

First, permittees have to show that dissolved salts are a cause of toxicity in the effluent. Since the effluent may contain multiple toxicants, permittees have to prove that dissolved salts are the primary source of toxicity. Next, permittees have to show that the dissolved salts are coming from their source water. Permittees need to complete each step in this process to receive the exemption for dissolved salts. The following paragraphs describe this process in more detail.

Are Dissolved Salts a Cause of Toxicity? To confirm that dissolved salts are a cause of effluent toxicity, the permittee will conduct at least one set of TIE characterization tests including an ion-exchange procedure. If the TIE tests show that dissolved salts are not a cause of effluent toxicity, the permittee should continue with the TRE to identify the toxicant or toxicants and to reduce or eliminate the toxicity.

If the TIE tests show that dissolved salts are a cause of effluent toxicity, the permittee then has to prove that they are the primary cause of toxicity.

Are Dissolved Salts the Primary Cause of Toxicity? The permittee may use the techniques described in the previous section “TDS Exemption—24-Hour Acute (100% End-of-Pipe) Tests” on page 125 to prove that dissolved salts are the primary cause of toxicity. If these techniques fail to do so, the permittee should continue with the TRE to address the toxicity. If the techniques prove that dissolved salts are the primary cause of toxicity, the permittee then has to prove that the dissolved salts are coming from the source water.

Are Dissolved Salts Coming from Source Water? To help prove that dissolved salts originate from the source water, the permittee should sample the facility’s intake water and/or raw water source and compare its dissolved salt concentration and ionic composition with those of the effluent. Increases in the dissolved salt content of the effluent due to process evaporation should also be evaluated where appropriate. In any case, if the effluent’s TDS concentration is greater than that of the source water or if the effluent’s ionic composition varies significantly from that of the source water, effluent limits or control measures may be included in the permit.

• • If the dissolved salts are not from the source water, the permittee has to comply with the total toxicity provisions of the Standards. If a protocol for an instream biological survey is approved by EPA, it may be possible for the permittee to attempt to demonstrate that aquatic life in the receiving water is not adversely affected by the TDS levels in the proposed permit.
• • If the dissolved salts are from the source water, the permittee may cease the TRE. Upon cessation of the TRE, TCEQ staff will, in conjunction with the permittee, evaluate the use of an alternative test species or a modified test protocol. The permittee may be required to continue testing if modifying the test protocol or using an alternate species resolves the toxic effect of the dissolved salts in the effluent. The TCEQ will then amend the permit to include these measures.

If an alternate species is unavailable or tests using a modified test protocol still demonstrate toxicity due to dissolved salts, the permittee will most likely be required to continue testing with the standard test species that is unaffected by the dissolved salts.

Discharges to marine waters are reviewed on a case-by-case basis and are subject to EPA review and approval in accordance with the MOA between the TCEQ and EPA concerning the TPDES program.

Ammonia Toxicity Controlling Potential Ammonia Toxicity Ammonia, a common component of domestic wastewater, has been shown to be toxic to aquatic organisms. Models used to determine effluent limits for oxygen-demanding constituents do not account for the toxicity that ammonia can exert. Therefore, to preclude receiving water toxicity, permits for certain types of facilities that have either

• • ammonia limits to maintain instream dissolved oxygen criteria; or
• • categorical ammonia limits that exceed 4 mg/L at the edge of the mixing zone will now include either modified limits for total ammonia or a chronic WET limit for the more sensitive species with a WET testing frequency of six times a year.

The modified ammonia limit or WET limit applies to the following types of facilities that discharge to perennial waters or within 3 miles of perennial waters:

• • major domestic facilities (design flow ≥ 1 MGD)
• • minor domestic facilities (design flow < 1 MGD) that discharge to a water body that: ◦ contains a threatened or endangered species or ◦ is listed for ammonia on an EPA-approved 303(d) list
• • industrial facilities that have WET testing requirements • industrial facilities that discharge to a water body that: ◦ contains a threatened or endangered species or ◦ is listed for ammonia on an EPA-approved 303(d) list

By following these guidelines, the TCEQ will ensure that it is not authorizing the discharge of toxic amounts of ammonia.

Toxicity Attributable to Ammonia TCEQ recognizes that the technology-based daily average ammonia- nitrogen limit of 3.0 mg/L included in most major domestic discharge permits generally precludes chronic toxicity to test species. Therefore, the TCEQ will implement this limit to address chronic toxicity attributable to ammonia in domestic discharge permits. The ammonia limit will be implemented in domestic discharge permits as follows:

• • For those facilities whose permits contain interim or final effluent phases that include a daily average ammonia-nitrogen limit of 3.0 mg/L, the persistent toxicity requirements are suspended until the effective date of the limit.
• • For those facilities whose permits do not contain interim or final effluent phase that include a daily average ammonia-nitrogen limit of 3.0 mg/L, TCEQ staff will amend the permits to include this limit.

The 3.0 mg/L ammonia-nitrogen limit is normally implemented in lieu of a chronic WET limit. However, should this limit prove ineffective in precluding toxicity, TCEQ staff will amend the permit to include an alternative limit and/or corrective measures protective of the receiving waters.

For those domestic facilities with seasonal ammonia limits and for industrial facilities with ammonia limits, such limits will not exceed 4.0 mg/L at the edge of the mixing zone (or 10 mg/L at the edge of the ZID for those permittees with 48-hour acute testing) unless the permittee agrees to a WET limit for the more sensitive species and a testing frequency for that species of six times per year (November, December, January, February, March, and July).

Toxicity Attributable to Diazinon The Standards previously contained a special provision (§ 307.6(e)(2)(E)) for those domestic wastewater facilities entering TREs due to Diazinon toxicity. However, since Diazinon can no longer be sold to the public, the previous conditions granting the TRE exemption (primary cause of toxicity and ubiquitous within the wastewater collection system) can no longer be met, so the special provision is no longer included in the Standards. Diazinon will now be treated as any other toxicant and will be subject to effluent limits.

Toxic Pollutants

General Provisions The Standards for toxic pollutants include general provisions, specific numerical criteria, and total (whole effluent) toxicity criteria. As stated in § 307.6 of the Standards:

• • Water in the state shall not be acutely toxic to aquatic life. Although acute criteria may be exceeded in a zone of initial dilution (ZID), there shall be no lethality to aquatic organisms that move through the ZID.
• • Water in the state shall not be chronically toxic to aquatic life except in mixing zones, below critical low-flow, and where there are only minimal aquatic life uses.
• • Water in the state shall be maintained to preclude adverse toxic effects on human health resulting from water recreation, consumption of aquatic organisms, or consumption of drinking water after reasonable treatment. Specific human health concentration criteria apply to water in the state with sustainable fisheries and/or designation or use as a public drinking water supply. These criteria do not apply within human health mixing zones.
• • Water in the state shall be maintained to preclude adverse toxic effects on aquatic life, terrestrial wildlife, livestock, or domestic animals, resulting from contact, consumption of aquatic organisms, or consumption of water.

Permits for discharges into intermittent streams are designed to protect against acute toxicity at the point of discharge. Permits for discharges into classified segments or unclassified water bodies determined to be perennial, intermittent with perennial pools, or within three miles of any water body that is perennial or intermittent with perennial pools are designed to protect against acute and chronic toxicity and to protect human health. Permits for discharges to the Houston Ship Channel and its tidal tributaries (Segments 1006 and 1007) are also designed to protect against acute and chronic toxicity and to protect human health.

In order to prevent toxicity due to chlorine, domestic dischargers who either: (1) request a new permit or amended permit (for increased flow)with permitted flow ≥ 0.5 MGD or (2) request a new, amended, or renewed permit with permitted flow ≥ 1 MGD will dechlorinate their effluent or use another form of disinfection. Domestic dischargers who renew a permit with a permitted flow ≥ 0.5 MGD but < 1 MGD will not be required to dechlorinate. The TCEQ does not require facilities discharging directly to the Rio Grande to dechlorinate.

Specific Numerical Criteria The numerical criteria for the protection of aquatic life (§ 307.6(c) of the Standards) are expressed for freshwater acute, freshwater chronic, saltwater acute, and saltwater chronic conditions. The numerical criteria for the protection of human health (§ 307.6(d) of the Standards) are expressed as receiving water concentrations to prevent contamination of drinking water, fish, and other aquatic life to ensure safe levels for human consumption. The two categories of human health criteria given in the standards are: (1) water and fish and (2) fish only. These standards apply whether or not they are addressed specifically in a wastewater discharge permit.

When submitting a permit application, the following types of facilities are required to include effluent data for those elements and compounds that have established standards and that the TCEQ believes likely to be present in the effluent:

• • domestic facilities requesting a permitted average flow equal to or greater than 1.0 million gallons per day (MGD) and/or with an approved pretreatment program.
• • domestic facilities requesting a permitted average flow less than 1.0 MGD on a case-by-case basis when facility inspection or other information provides reasonable potential to expect the presence of toxic pollutants in the receiving water or effluent.
• • industrial facilities.

Deriving Permit Limits for Aquatic Life Protection General Approach In order to determine the effluent concentration of a toxic pollutant necessary to protect instream water quality criteria, TCEQ staff uses the general approach found in the EPA publication entitled Technical Support Document for Water Quality-based Toxics Control, EPA/505/2-90-001.

• • TCEQ staff applies acute criteria for discharges into intermittent streams with minimal aquatic life uses and assume a critical low-flow of 0.0 ft3/s.
• • Discharges into intermittent streams that flow into perennial waters (including perennial wetlands) within a moderate distance downstream (normally 3 miles) are analyzed using acute criteria in the intermittent stream and acute and chronic criteria; and the critical low-flow of the perennial waters to determine whether more stringent requirements are needed to protect the perennial waters.
• • Permit limits are developed to ensure that intermittent streams with seasonal aquatic life uses of limited, intermediate, high, or exceptional will meet chronic toxic criteria during the seasons; and typical flow conditions in which these uses occur.
• • TCEQ staff applies chronic criteria at critical mixing conditions for other water bodies with limited, intermediate, high, or exceptional aquatic life uses (lakes, bays, estuaries, tidal rivers, perennial wetlands), unless acute criteria are more protective.

Water Quality Parameters That Affect Aquatic Life Criteria For certain substances, water quality criteria are a function of one or more of the following receiving water parameters:

• • hardness • pH • chloride • total suspended solids.

Fifteenth percentile values of segment hardness, pH, and TSS data are considered critical conditions (see the tables in Appendix D of this document). Basin values are used when there is insufficient segment data.

The fiftieth percentile value of segment chloride data is used to implement the freshwater silver standard for aquatic life protection (see Appendix D). Basin values are used when there is insufficient segment data.

TCEQ staff usually obtains this information from Appendix D, but may also use information in the TCEQ’s Surface Water Quality Monitoring (SWQM) database. The permittee may also supply site-specific data. The procedures to collect site-specific data for hardness, pH, chloride, TSS, and partition coefficients are outlined in the section of this document entitled “Collecting Site-Specific Data” on page 155.

The numerical standards for toxic pollutants apply to total recoverable concentrations, except for designated metals. For these metals, the numerical standards apply to dissolved concentrations. Saltwater and freshwater metals criteria listed in Table 1 of the Standards were derived by multiplying the current standard by the appropriate listed conversion factor to obtain a percent dissolved standard. The resultant value is the percent dissolved metal in the tests used by EPA to derive the criteria.

In order to determine instream compliance with the numerical standards for dissolved concentrations, TCEQ staff use partition coefficients based on the information shown in Table 6 (on page 159) and/or on site-specific data. The use of partition coefficients determines how much metal is dissolved in the receiving water. Guidelines for developing a site-specific partition coefficient are given in the section of this document entitled “Collecting Site-Specific Data” on page 155.

The TCEQ evaluates metals not included in Table 6 by assuming the dissolved concentration equals the total recoverable concentration unless sufficient additional information and data are presented that justify a different fraction of dissolved metal.

Calculating Effluent Fractions The first step in developing effluent limits based on water quality criteria for aquatic life protection is to calculate the effluent fraction at the edge of the mixing zone and ZID. Unless available information shows otherwise, complete mixing is assumed at the edge of the mixing zone, allowing the fraction of effluent at this location to be calculated.

Perennial Freshwater Streams and Rivers and Some Narrow Tidal Rivers For discharges to perennial streams and rivers and narrow tidal rivers (that are < 400 feet across and have upstream flow data), 25% of the 7Q2 is used to calculate the effluent fraction (EF) at the edge of the ZID as follows: QE E F at edge of MZ  [QS  QE ] QE E F at edge of ZID  [(0.25)(QS )  QE ]

where: QE = effluent flow QS = 7Q2 stream flow

Lakes, Bays, Wide Tidal Rivers, and Some Narrow Tidal Rivers For discharges to lakes, bays, wide tidal rivers (≥ 400 feet across), and narrow tidal rivers (< 400 feet across) that do not have upstream flow data, the fraction of effluent used in each WLA is the amount of effluent at the edge of the ZID or mixing zone as predicted by empirical models. A more complete discussion of the mixing assumptions and exceptions and corresponding effluent fractions is provided in the section of this document entitled, “Critical Conditions for Aquatic Life Protection” on page 72.

Effluent Flow The effluent flow that is used for dilution calculations is determined on a case-by-case basis. In general, however:

• • Domestic wastewater discharge assessments are based upon the final average permitted flow.
• • Industrial wastewater discharge assessments for renewals are based upon the highest monthly average discharge of the preceding two-year period. Other flows may be used if the highest monthly average discharge does not reflect normal operating conditions. For proposed new or increased discharges, the requested average flow is used. The effluent flow used to calculate the WLA is also used to calculate the final mass limits.

Calculating Waste Load Allocations The next step in developing effluent limits based on water quality criteria for aquatic life protection is to calculate a waste load allocation from the acute criteria (WLAa) and a waste load allocation from the chronic criteria (WLAc).

• • The WLAa equals the effluent concentration that will not cause instream criteria to be exceeded outside the zone of initial dilution (ZID).
• • The WLAc equals the effluent concentration that will not cause instream criteria to be exceeded outside the mixing zone (MZ).

This calculation requires the use of the appropriate effluent fraction as well as the bioavailable fraction of the pollutant. (For more information on calculating the bioavailable fraction, see the subsection of this document entitled “TSS, Partition Coefficients, and Bioavailable Fractions of Metals” on page 159.) The proportion of effluent at the edge of the mixing zone is used to calculate the WLAc, and the proportion of effluent at the edge of the ZID is used to calculate the WLAa. The following equations are used to calculate the waste load allocations:

Chronic Criterion WLAc  ( Bioavailab le Fraction )( E F at edge of MZ )

Acute Criterion WLAa  ( Bioavailab le Fraction )( E F at edge of ZID )

where: WLAa = waste load allocation based on acute criterion WLAc = waste load allocation based on chronic criterion Acute Criterion = aquatic life acute numerical criterion Chronic Criterion = aquatic life chronic numerical criterion Bioavailable Fraction = fraction of the pollutant that is defined to be available to organisms EF edge of ZID = proportional contribution of effluent to receiving water at the edge of the ZID EF edge of MZ = proportional contribution of effluent to receiving water at the edge of the mixing zone

Calculating the Long-Term Average Once the WLAa and the WLAc are calculated, the TCEQ determines the long-term average (LTAa and LTAc) of the treatment system performance that is necessary to meet the respective WLA with a given probability. The TCEQ bases its calculation on a lognormal probability distribution that is known to describe treatment system performance. Figure 7 shows the general shape of a lognormal probability distribution. The LTAa and the LTAc are calculated with equations that describe this function. See the Technical Support Document for Water Quality-based Toxics Control, EPA/505/2-90-001, March 1991, for more information.

Figure 7. Probability Distribution that Describes Treatment System Performance

The final equations used to calculate the LTAa and the LTAc are:

LTAa = 0.32 WLAa (99% probability) LTAa = 0.573 WLAa (90% probability) LTAc = 0.61 WLAc (99% probability) LTAc = 0.770 WLAc (90% probability)

While the derivation of these equations is quite complex (see Figure 8 on page 138), the important thing to recognize is that the equations are driven by the values that are assumed for n (averaging period), CV (coefficient of variation), and Z (probability distribution factor). The values that TCEQ assumes for these variables are:

n= 7 (7-day average, for chronic criteria) 1 (24-hour average, for acute criteria) Z= 1.282 (90% probability for discharges to freshwater streams, rivers, and narrow tidal rivers with upstream flow data) 2.326 (99% probability for discharges to lakes, reservoirs, bays, estuaries, wide tidal rivers, and narrow tidal rivers without upstream flow data) CV = 0.6

Calculating Daily Average and Daily Maximum Permit Limits The calculated values of LTAa and LTAc are compared. The smaller LTA is limiting and is used to calculate the daily average and daily maximum concentration limits (DLY AVG and DLY MAX, respectively) using the following equations:

DLY AVG = 1.47 LTA (n = 12) DLY MAX = 3.11 LTA (n = 1)

These equations are driven by the values for Z (2.326), CV (0.6), and n, where n is now the number of sample events per month. For the daily average concentration limit, the TCEQ assumes n = 12 for consistency, even if the sampling frequency defined in the permit is not 3 per week. For the daily maximum concentration limit, the TCEQ uses n = 1. See Figure 9 on page 139 for detailed derivations of these equations. Once the daily average and daily maximum concentration limits are determined, a mass limit is calculated using the same effluent flow used to calculate the WLA.

LTA = exp(un + 0.5sn2) un = ln(WLA) - Zsn sn2 = ln [1 + (CV2/n)]

Acute Criteria

sn2 = ln [1 + (0.62/1)] = 0.307 sn = 0.555

For Z = 2.326 (99% probability): For Z = 1.282 (90% probability):

un = ln(WLAa) - (2.326)(0.555) un = ln(WLAa) - (1.282)(0.555) un = ln(WLAa) - 1.291 un = ln(WLAa) - 0.712 LTAa = exp[ln(WLAa) - 1.291 + 0.5(0.307)] LTAa = exp[ln(WLAa) - 0.712 + 0.5(0.307)] LTAa = exp[ln(WLAa) -1.137] LTAa = exp[ln(WLAa) - 0.558] LTAa = WLAa/e1.137 LTAa = WLAa/e0.558 LTAa = 0.32 × WLAa LTAa = 0.573 × WLAa

Chronic Criteria

sn2 = ln [1 + (0.62/7)] = 0.050 sn = 0.224

For Z = 2.326 (99% probability): For Z = 1.282 (90% probability): un = ln(WLAc) - (2.326)(0.224) un = ln(WLAc) - (1.282)(0.224) un = ln(WLAc) - 0.521 un = ln(WLAc) - 0.287 LTAc = exp[ln(WLAc) - 0.521 + 0.5(0.050)] LTAc = exp[ln(WLAc) - 0.287 + 0.5(0.050)] LTAc = exp[ln(WLAc) -0.496] LTAc = exp[ln(WLAc) - 0.262] LTAc = WLAc/e0.496 LTAc = WLAc/e0.262 LTAc = 0.61 × WLAc LTAc = 0.770 × WLAc

Figure 8. Derivation of Equations Used to Calculate the Long-Term Average

LIMIT = exp(un + Zsn) un = ln(LTA) - 0.5sn2 sn2 = ln [1 + (CV2/n)]

Daily Average

sn2 = ln [1 + (0.62/12)] = 0.030 sn = 0.173 un = ln(LTA) - (0.5)(0.030) un = ln(LTA) - 0.015 DLY AVG = exp[ln(LTA) - 0.015 + (2.326)(0.173)] DLY AVG = exp[ln(LTA) + 0.387] DLY AVG = LTA × e0.387 DLY AVG = 1.47 × LTA

Daily Maximum

sn2 = ln [1 + (0.62/1)] = 0.307 sn = 0.555 un = ln(LTA) - (0.5)(0.307) un = ln(LTA) - 0.154 DLY MAX = exp[ln(LTA) - 0.154 + (2.326)(0.555)] DLY MAX = exp[ln(LTA) + 1.137] DLY MAX = LTA × e1.137 DLY MAX = 3.11 × LTA

Figure 9. Derivation of Equations Used to Calculate Daily Average and Daily Maximum Concentration Limits

Deriving Permit Limits for Human Health Protection General Approach In order to calculate the effluent concentration of a toxic pollutant necessary to protect instream water quality criteria, TCEQ staff use the general approach found in the EPA publication entitled Technical Support Document for Water Quality-based Toxics Control, EPA/505/2-90-001, March 1991.

• • The human health criteria in Table 2 of the Standards apply to all water bodies with (1) a designation or use as a public drinking water supply and/or (2) sustainable fisheries, including:

◦ all designated segments.

◦ perennial streams with a stream order of three or greater.

◦ lakes having a volume equal to or greater than 150 acre-feet and/or a surface area equal to or greater than 50 acres.

◦ all bays, estuaries, and tidal rivers.

◦ permanently inundated wetlands (including tidal wetlands).

◦ any other waters that potentially have sufficient fish production or fishing activity to create significant long-term (sustainable) human consumption of fish.

• • Human health criteria are applied to any discharge located within three miles upstream of the types of water bodies listed above.
• • Waters with a limited, intermediate, high, or exceptional aquatic life use but no sustainable fishery are considered to have an incidental fishery. Numerical criteria applicable to waters with incidental fisheries are ten times higher than for sustainable fisheries because the consumption rates assumed in the Standards for incidental fisheries are ten times lower than those for sustainable fisheries. This level of human health protection applies to discharges directly to or within three miles upstream of waters with an incidental fishery.
• • Specific human health criteria are applied as long-term average exposure criteria designed to protect populations over a lifetime.

Calculating the Effluent Fraction The first step in developing effluent limits based on water quality for human health protection is to calculate the effluent fraction at the edge of the human health mixing zone. Unless available information shows otherwise, complete mixing is assumed at the edge of the mixing zone, allowing the fraction of effluent at this location to be calculated.

Perennial Freshwater Streams and Rivers, Intermittent Streams with Perennial Pools, and Some Narrow Tidal Rivers For discharges to perennial freshwater streams and rivers, intermittent streams with perennial pools, and narrow tidal rivers (that are < 400 feet across and have upstream flow data), the proportion of effluent used in WLAh is calculated as follows: QE E F at edge of HH MZ  [QHM  QE ] where: QE = effluent flow QHM = harmonic mean stream flow

TCEQ staff use data from the nearest stream gaging station or available site-specific information to determine the harmonic mean flow.

Lakes, Bays, Wide Tidal Rivers, and Some Narrow Tidal Rivers For discharges to lakes, bays, wide tidal rivers (≥ 400 feet across), and narrow tidal rivers (< 400 feet across) that do not have upstream flow data, the fraction of effluent used in the WLAh is the amount of effluent at the edge of the human health mixing zone as predicted by empirical models. A discussion of the mixing assumptions and exceptions and corresponding effluent fractions is given in the section of this document entitled “Mixing Zones and Critical Conditions for Human Health Protection” on page 78.

Effluent Flow The effluent flow that is used for dilution calculations is determined on a case-by-case basis. In general, however:

• • Domestic wastewater discharge assessments are based upon the final average permitted flow.
• • Industrial wastewater discharge assessments for renewals are based upon the average of monthly average flow values over the preceding two-year period. For proposed new or increased discharges, the requested average flow is used.

Calculating the Waste Load Allocation The next step in developing effluent limits based on water quality criteria for human health protection is to calculate a waste load allocation (WLAh). The WLAh equals the effluent concentration that will not cause criteria to be exceeded outside the human health mixing zone. This calculation requires the use of the appropriate effluent fraction as well as the bioavailable fraction of the pollutant. (For more information on calculating the bioavailable fraction, see the subsection of this document entitled “TSS, Partition Coefficients, and Bioavailable Fractions of Metals” on page 159.) The proportion of effluent at the edge of the human health mixing zone is used to calculate the WLAh. The following equation is used to calculate the waste load allocation:

HH Criterion WLAh  ( Bioavailab le Fraction )( E F at edge of HH MZ )

where: HH Criterion = appropriate human health numerical criterion Bioavailable Fraction = fraction of the pollutant that is defined to be available to organisms EF at edge of HH MZ = proportional contribution of effluent to receiving water at the edge of the human health mixing zone

Calculating the Long-Term Average and Permit Limits The WLAh is considered to be an annual average (n = 365 days). The long-term average (LTAh), daily average concentration (DLY AVG), and daily maximum concentration (DLY MAX) are calculated at 99% probability (Z = 2.326) using the same process that was used for the aquatic life calculations (see Figure 8 on page 138 and Figure 9 on page 139). The final equations are as follows:

LTAh = 0.930 WLAh (n = 365) DLY AVG = 1.47 LTAh (n = 12) DLY MAX = 3.11 LTAh (n = 1)

Establishing Permit Limits for Toxic Pollutants without Criteria In some instances, potentially toxic materials for which no specific numerical criteria have been developed are used in a treatment process or are present in an effluent. Where necessary, permit limits are developed for these materials using available toxicity data and the method described in this section. For substances without standards that are reported in the permit application, TCEQ staff screen the reported value against the agency-specified minimum analytical level (MAL). Parameters less than the MAL are screened out with no further action necessary. Numerical criteria and permit limits are developed, if appropriate, for parameters exceeding the MAL. For substances that commonly occur naturally at concentrations above the MAL, alternative screening criteria are used.

Aquatic Life Criteria The TCEQ develops permits that protect against acute and chronic toxicity in receiving waters at and above critical conditions, as appropriate. Critical conditions in receiving waters are established using methods discussed in the chapter of this document entitled “Mixing Zones and Critical Conditions” beginning on page 70. As stated in § 307.6(c)(7) of the Standards, water quality criteria for the protection of aquatic life are established using the methods described in this subsection.

Specific numerical criteria are calculated using the method outlined in the following documents if toxicity data requirements outlined in these documents are met:

• • Guidelines for Deriving Water Quality Criteria for the Protection of Aquatic Life and Its Uses (45 FR 79341-79347 November 28, 1980).
• • Summary of Revisions to “Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses” (50 FR 30792-30793, July 29, 1985).

Acute Criteria If the data requirements in the documents cited above are not met, acute water quality criteria are calculated as follows:

ACUTE CRITERIA = 0.30 × LC50 of most sensitive species

where: LC50 = the concentration of a toxicant that is lethal (fatal) to 50% of the organisms tested in a specified time period

Chronic Criteria The derivation of chronic water quality criteria for the protection of aquatic life depends on the persistence and bioaccumulative capacity of the material. A pollutant’s potential to bioaccumulate can be expressed by any of the following:

• • the bioaccumulation factor (BAF) • the bioconcentration factor (BCF) • the octanol-water partition coefficient (Kow).

The BAF and the BCF measure the concentration of a substance in a living organism relative to the concentration of the substance in the surrounding medium. The BAF accounts for substance intake from both food and the surrounding medium, while the BCF accounts for intake from the surrounding medium only. The Kow estimates the tendency of a substance to partition from water to organic media, such as lipids present in living organisms. The Kow can be used in place of the BCF or BAF when limited experimental data are available.

For the purposes of this section, the TCEQ will use the following criteria to determine whether a chemical is persistent or bioaccumulative:

• • A chemical is persistent if it has a soil, sediment, or water half-life of 60 days or greater. It is highly persistent if it has a soil, sediment, or water half-life of six months or greater. Half-life is defined as the time required for 50% of a chemical to degrade or to be removed from the local environment by some physical process. 12
• • A chemical is bioaccumulative if its BAF or BCF is 1,000 or greater. It is highly bioaccumulative if either its BAF or BCF is 5,000 or greater.

The following methods for deriving chronic criteria are consistent with § 307.6(c)(7) of the Standards.

Nonpersistent toxic compounds:

CHRONIC CRITERIA = 0.10 × LC50 of most sensitive species

Persistent toxic compounds:

CHRONIC CRITERIA = 0.05 × LC50 of most sensitive species

Bioaccumulative toxic compounds:

CHRONIC CRITERIA = 0.01 × LC50 of most sensitive species

12 Rand, Gary M. (ed.), 1995. Fundamentals of Aquatic Toxicology (Second Edition). CRC Press.

Data Considerations • Toxicity data used in these equations should be derived from tests using the most sensitive native species.

• • If no LC50 data are available for native species, non-native species data may be used.
• • LC50s are selected that have appropriate end points (mortality), appropriate duration (96 hours for vertebrates and 48 hours for invertebrates), and appropriate species (freshwater or saltwater).
• • LC50 data based on a freshwater species are not appropriate for saltwater criteria development and vice versa.
• • Data from flow-through tests is preferred over static renewal tests.
• • Where more than one acceptable test endpoint is available for a given species, a geometric mean of the LC50 data should be used for the criteria calculation.
• • Toxicity tests using aquatic plants are not considered at this time.
• • When evaluating BAFs and BCFs for a persistence determination, lab- derived BAFs/BCFs are preferred over logKow-based regression equations.
• • When multiple BAF/BCF data points are available for similar taxa (same genus), the geometric mean of these values should be used as opposed to one single data point.

There may be instances when toxicity data are only available for species not representative of the receiving waters, test durations are varied, or other undesirable circumstances exist. In this instance, it may be more appropriate to rely on a quantitative structure-activity relationship (QSAR) model for LC50 prediction or to use a method that differs from the one described in this section.

If acute or chronic criteria need to be derived for biocides, other water treatment chemicals, or other constituents present in the effluent for which water quality standards are not established, the methods just described are used. The following information is typically needed to determine these criteria:

• • product information sheet • material safety data sheet (MSDS) if available • product toxicity data • permitted discharge volume • expected concentration of product in effluent • discharge location.

Human Health Criteria Water quality criteria for human health protection are derived as stated in § 307.6(d)(8) and (9) of the Standards.

• • For known or suspected carcinogens, a cancer risk of 10-5 (1 in 100,000) is applied to the most recent numerical criteria adopted by EPA and published in the Federal Register.
• • For toxic materials not defined as carcinogens, the most recent numerical criteria adopted by EPA and published in the Federal Register are applicable.
• • Criteria calculations for noncarcinogens are based on childhood exposure, and criteria calculations for carcinogens are based on a lifetime of exposure.
• • In both cases, if a maximum contaminant level (MCL) applies and is less than the resulting criterion, then the MCL applies to public drinking water supplies as stated in § 307.6(d)(3)(G) of the Standards.
• • Numerical criteria for pollutants that bioconcentrate are derived in accordance with the general procedures in the EPA guidance document entitled Assessment and Control of Bioconcentratable Contaminants in Surface Waters (March 1991).

In the absence of available criteria, numerical criteria may be derived from available information and calculated using the following formulas:

WATER AND FISH, CARCINOGENS ( RL )( BW )(U ) HH CRITERIA ( g / L)  CPF [WI  ( FC )( LC )( BCF )]

FISH TISSUE ONLY, CARCINOGENS

( RL )( BW )(U ) HH CRITERIA ( g / L)  (CPF )( FC )( LC )( BCF )

where: RL = risk level (1 in 100,000, or 10-5)

BW = body weight of average adult (70 kg) U= unit conversion factor to express criteria in µg/L (1000 µg/mg) CPF = carcinogenic potency factor (oral slope factor, kg-day/mg) WI = amount of water consumed per day (2 L/day) FC = amount of fish tissue consumed (0.0175 kg/day) LC = lipid correction factor to adjust BCFs normalized to 7.6% lipids to represent a 3% lipid content (3% ÷ 7.6%) BCF = bioconcentration factor (L/kg)

WATER AND FISH, NONCARCINOGENS

( RfD )( BW )(U ) HH CRITERIA ( g / L)  WI  ( FC )( LC )( BCF )

FISH TISSUE ONLY, NONCARCINOGENS

( RfD )( BW )(U ) HH CRITERIA ( g / L)  ( FC )( LC )( BCF )

where: RfD = reference dose (mg toxicant/kg human body weight/day) BW = body weight of average child (15 kg) U= unit conversion factor to express criteria in µg/L (1000 µg/mg) WI = amount of water consumed per day (0.64 L/day) FC = amount of fish tissue consumed (0.0056 kg/day) LC = lipid correction factor to adjust BCFs normalized to 7.6%

lipids to represent a 3% lipid content (3% ÷ 7.6%) BCF = bioconcentration factor (L/kg)

These formulas convert BCFs that are normalized to 7.6% lipid content to represent a 3% lipid content. The majority of recently developed BCFs have been normalized to represent a 3% lipid content; therefore, it is essential to research the BCF being used in the equation to ascertain what lipid content the BCF represents. When using a BCF that is already normalized to 3% lipid content, the lipid correction factor (LC) equals one.

Correcting for Background Concentrations In developing effluent limits based on water quality criteria, the preferred method of accounting for background concentrations of toxic pollutants is through total maximum daily load (TMDL) allocations. However, until TMDLs are approved and available for particular assessment units (AUs) and toxic pollutants of concern, the procedure discussed in this section is used to screen applications and develop permit limits.

For purposes of this section, the following definitions apply:

Background concentration: the water quality in a particular water body that would occur if that water body were relatively unaffected by human activities.

Ambient concentration: the existing water quality in a particular water body.

Procedure for Developing Permit Limits The procedure for screening application data and developing permit limits is shown in Figure 10 on page 151. If an approved TMDL exists for a particular pollutant and AU, the permit incorporates a limit as established by the TMDL procedure. In the absence of an approved TMDL, application data is screened using reliable background concentration data, if such data exist.

Table 5 on page 150 lists reliable background concentration data that are used routinely in application screening. Data are added to Table 5 as they become available.

When reliable background concentration data are not available, data are screened with the assumption that the background concentration is zero. The assumption of a zero background concentration may be reconsidered on a case-by-case basis as new information becomes available.

When the background concentration is less than the instream criterion, a mass balance approach is used to determine waste load allocations for affected parameters. This approach is applicable for calculating permit limits for both aquatic life and human health protection.

The following equation is used to calculate the waste load allocation (WLA): Criterion  [(1  E F )(C B )( Bioavailable Fraction)] WLA  ( Bioavailable Fraction)( E F )

where: WLA = waste load allocation (total concentration) Criterion = appropriate numerical criterion (dissolved, free ion, or total concentration as specified in Table 1 or 2 of the Standards) EF = proportional contribution of effluent to receiving water CB = background concentration of pollutant (total concentration) Bioavailable fraction of the pollutant that is defined to be available to Fraction = organisms

When the background concentration is assumed to be zero, the equation above reduces to those shown in the sections of this document entitled “Deriving Permit Limits for Aquatic Life Protection” on page 131 and “Deriving Permit Limits for Human Health Protection” on page 140.

When the background concentration is equal to or greater than the instream criterion, then effluent permit limits are developed to ensure that no degradation of water quality will occur, in accordance with the procedures to protect existing uses (see the chapter of this document entitled “Antidegradation” on page 55).

Table 5. Background Concentrations of Toxic Metals in Texas Estuaries Total Total Total Total Segment Water Body Copper Lead Silver Zinc Number (μg/L) (μg/L) (μg/L) (μg/L) 1401 Colorado Estuary 0.99 0.27 0.003 1.76

2412 Sabine Estuary 1.00 0.19 0.004 1.20

2421 Galveston Estuary 0.75 0.21 0.004 1.90

2439 Galveston Estuary 0.75 0.21 0.004 1.90

2451 Lavaca-Matagorda Estuary 0.57 0.12 0.002 1.25

2453 Lavaca-Matagorda Estuary 0.57 0.12 0.002 1.25

2462 San Antonio Estuary 1.23 0.20 0.003 2.18

2481 Corpus Christi Estuary 0.70 0.14 0.003 4.04 Notes: Background concentrations represent the geometric mean of the data set. Data compiled from Benoit, G. and P. H. Santschi, 1991; Trace Metals in Texas Estuaries; Prepared for the Texas Chemical Council; Texas A&M University at Galveston, Department of Marine Science.

Has a TMDL been approved for the Establish permit limits using pollutant of concern YES the TMDL allocation for the in the segment that pollutant of concern in the receives the receiving segment. discharge?

NO

Are reliable Screen application data for background YES compliance with the criterion using concentration background concentration data. data available?

NO Is criterion Screen application data for exceeded? compliance with the criterion using background concentration = 0. NO YES

No permit Include permit limit limit (with required. compliance Is schedule if YES criterion appropriate). exceeded?

NO Include permit limit (with compliance schedule if No permit limit required. appropriate). Background Background concentration considered concentration considered on a case-by-case basis. on a case-by-case basis.

Figure 10. Protocol for Including Background Concentrations in Permit Limit Calculations

Obtaining Reliable Water Quality Data Reliable background concentration data are needed for application screening. Samples should be collected, analyzed, and handled as follows:

1. Collect and preserve samples using techniques that conform with EPA-approved methods. Collect and preserve samples for metals using clean techniques (see item 3a below) or equivalent.

2. Analyze samples using EPA-approved methods. Analyses should meet agency-specified minimum analytical levels (MALs) (see Tables E-1 and E-2 in Appendix E) for the pollutant or pollutants of concern.

3. Sample collection, preservation, handling, storage, analysis, quality assurance, and quality control procedures should be comparable to those specified in the following documents:

a. Surface Water Quality Monitoring Procedures, Volume 1: Physical and Chemical Monitoring Methods for Water, Sediment, and Tissue , RG-415, Texas Commission on Environmental Quality, December 2003 (or latest revision).

b. Work Plan/Quality Assurance Project Plan for Near Coastal Waters Project, Sec. 104(b)(3), Grant No. X-006559-01-0, Total Maximum Daily Loads of Selected Heavy Metals in the Houston Ship Channel, San Jacinto River (Tidal) and Upper Galveston Bay, Texas Water Commission, Environmental Assessment Division, August 1993.

c. Benoit, G. and P. H. Santschi, 1991; Trace Metals in Texas Estuaries; Prepared for the Texas Chemical Council; Texas A&M University at Galveston, Department of Marine Science.

4. Collect freshwater samples during moderate or low stream flow conditions. Collect marine or tidally influenced water samples during low freshwater inflow conditions. Such flow conditions should prevail for at least one week prior to data collection.

5. When gathering data for metals, measure TSS and hardness at each freshwater sample site. When gathering data for silver, measure chloride at each sample site.

Once-Through Cooling Water Discharges Applicability As stated in § 307.8(d) of the Standards, the TCEQ does not require effluent limits based on water quality criteria for those pollutants discharged in once-through cooling water where no measurable increase of the pollutant concentration occurs in the effluent as compared to the intake water.

This exemption applies exclusively to once-through cooling water discharges. It excludes facilities withdrawing from one water body and subsequently discharging the cooling water into a different water body; such facilities have to maintain and protect water quality and applicable water quality standards in the receiving water. Exceptions to this exclusion are considered on a case-by-case basis (for example, intake is in a tidal water body and discharge is to a downstream bay or estuary).

Permit Action A permittee should request a once-through cooling water exemption during the wastewater permit application process. The terms and conditions of the new permit may vary depending on existing permit conditions and the amount of data available.

• • If an existing permit has final effluent limits based on water quality criteria for the pollutant of concern, these limits will remain in the reissued permit until sufficient monitoring has been conducted to support the exemption.
• • If an existing permit does not include effluent limits based on water quality criteria for the pollutant of concern, interim effluent limits or monitoring requirements may be included in the permit. The permit will be issued for a term of up to three years to allow time for the permittee to perform a statistical study and source evaluation.

Language will also be included in the “Other Requirements” section of the permit that outlines what the permittee must do and the time frame (up to three years) in which it must be done. Included in this language will be a statement as follows: “If the permittee does not conduct or complete the study at least 180 days prior to the permit expiration date, the following effluent limits for (pollutant of concern) will become effective immediately in a reissued permit.”

The TCEQ will coordinate with the EPA on case-by-case reviews for these situations.

The permit will contain a special provision stating that the exemption will be approved or denied based upon the findings of the statistical study and the findings of the source investigation.

Statistical Study To demonstrate that no measurable increase in the pollutant of concern occurs through the once-through cooling water outfall, the applicant needs to perform a statistical analysis to determine whether a pollutant’s average concentration demonstrates a statistically significant increase at the 95 percent confidence level. All applicants considering an exemption are urged to work with TCEQ staff to determine an acceptable work plan.

Data Collection The applicant should collect at least 10 paired grab samples, where the term “paired” refers to both intake and discharge samples being collected within one hour of each other. In cases where the hydraulic retention time in the cooling system exceeds one hour, the paired samples may be collected more than one hour apart. Information regarding the hydraulic retention time should be included in the study report.

Each intake sample should be depth integrated from the water surface down to the depth of the intake pipe. For discharges to a marine water body, samples should be collected during slack tide. Samples should be collected at least 10 days apart from each other and be representative of normal operating conditions. Clean techniques for field and analytical procedures should be considered when determining trace metal levels in noncontact cooling water (USEPA Method 1669 - April 1995).

Statistical Analysis To demonstrate that no measurable increase in a pollutant occurs through the once-through cooling water outfall, the applicant should perform a statistical analysis to determine whether the pollutant’s average concentration demonstrates a statistically significant increase at the 95 percent confidence level. The two-tailed Student’s t-test should be used to compare the influent concentrations to the effluent concentrations. The applicant should calculate the mean and standard deviation for each paired data set using a lognormal distribution. When portions of a data set are at concentrations less than the MAL, the applicant should adjust the mean and standard deviation calculation with appropriate methodology.

Examples of appropriate methods include the delta lognormal approach as described in the Technical Support Document for Water Quality-based Toxic Control, EPA/505/2-90-001, and the Cohen test method described in the Statistical Analysis of Ground Water Monitoring Data at RCRA Facilities, NTIS No. PB89-151047.

Source Investigation A source investigation of the pollutant will also be performed by the applicant requesting the exemption. All applicants performing source investigations are urged to work with TCEQ staff to determine appropriate sampling locations. Potential sources include but are not limited to:

• • current and historical sources of the pollutant in question (such as metal cleaning waste) • cooling tubes • pollutants in tributaries entering the reservoir • pollutants in the soils surrounding the reservoir.

This information can be used to support the applicant’s contention that the discharge of once-through cooling water does not contribute to the pollutant concentration in the reservoir. Low-volume waste streams are addressed by:

• • demonstrating that the pollutant of concern cannot be added by the waste stream; or
• • establishing a permit limit to attain water quality standards at the internal outfall.

Exemption Approval or Denial Based on the results of the statistical analysis and the source investigation, TCEQ staff recommends granting or denying the exemption.

• • If the exemption is approved, the permit is issued without effluent limits based on water quality criteria for the pollutant of concern. A statement is included in the “Other Requirements” section of the permit that a once-through cooling water exemption for the pollutant of concern has been approved for the appropriate outfall. Long-term monitoring for the exempted pollutant is also included in the “Other Requirements” section of the permit.
• • If the exemption is not approved, the permit is amended to include appropriate effluent limits based on water quality criteria, including any appropriate compliance period.

Note that if the receiving water body does not attain water quality standards for the pollutant in question, the exemption can still be granted, but the applicant may be required to submit additional data.

Collecting Site-Specific Data Permittees may collect data on site-specific hardness, pH, chloride, TSS, or metals to support calculation of some water quality criteria and site- specific partition coefficients or bioavailable fractions of metals.

• • Hardness—water quality criteria for certain metals (cadmium, trivalent chromium, copper, lead, nickel, and zinc) depend on hardness.
• • pH—water quality criteria for pentachlorophenol depend on pH.
• • Chloride—the percentage of dissolved silver that is in free ionic form depends on chloride.
• • TSS—partition coefficients, and hence, bioavailable fractions of metals, depend on TSS.
• • Metals—the bioavailable fractions of metals can be determined directly by measuring dissolved concentrations and total recoverable concentrations.

The TCEQ usually uses segment or basin values for hardness, pH, chloride, and TSS from the tables in Appendix D of this document. Permittees who think that these default values do not adequately reflect conditions in their receiving water may collect site-specific data and submit it to the TCEQ for review.

Guidelines for collecting hardness, pH, and chloride data are presented in the next subsection, entitled “Hardness, pH, and Chloride.” Guidelines for collecting TSS and metals data and for developing site-specific partition coefficients and bioavailable metals fractions are presented in the subsection entitled “TSS, Partition Coefficients, and Bioavailable Fractions of Metals” on page 159.

Hardness, pH, and Chloride

Hardness In general, most metals are more toxic in water that has low hardness values (soft water). Therefore, water quality criteria are more stringent for receiving waters having a low hardness value. The TCEQ uses the 15th percentile of basin or segment hardness data (ranked from lowest to highest value) to calculate hardness-dependent criteria. Before collecting any site-specific data, it is advisable for the permittee to determine what default value was used in the TCEQ’s calculations.

The following items outline acceptable procedures for collecting site- specific hardness data:

• • Collect samples from the receiving water upstream of the discharge, if available, and outside of the regulatory mixing zone. For more information about mixing zones, see § 307.8(b) of the Standards and the section of this document entitled “Mixing Zones and ZIDs for Aquatic Life Protection” on page 70.

If no water is present upstream of the discharge, samples may be taken from a nearby perennial stream or from the nearest downstream perennial stream. Samples should occur above the confluence with the receiving stream so that samples are not affected by the effluent hardness.

• • Collect a minimum of 30 samples from the receiving water to represent a range of seasonal conditions. The applicant is responsible for providing a minimum of 30 valid data points to obtain a statistically reliable estimate of the 85th percentile value of the dissolved-to-total ratio. Samples should typically be taken a minimum of one week apart from one another.
• • Measure hardness as mg/L of CaCO3.
• • If the permit includes whole effluent toxicity (WET) testing requirements and receiving water is used as the control, control hardness values may also be used to supplement any site-specific data that is collected. Laboratory dilution water may not be used to provide hardness data.

pH Pentachlorophenol is more toxic in water that has low pH (acidic). Therefore, the permit limit for pentachlorophenol is more stringent for facilities whose receiving water has low pH. The TCEQ uses the 15th percentile of basin or segment pH data (ranked from lowest to highest value) to calculate freshwater criteria for pentachlorophenol. Before collecting any site-specific data, it is advisable for the permittee to determine what default value was used in the TCEQ’s calculations.

The following items outline acceptable procedures for collecting site- specific pH data:

• • Collect samples from the receiving water upstream of the discharge, if available, and outside of the regulatory mixing zone. For more information about mixing zones, see § 307.8(b) of the Standards and the section of this document entitled, “Mixing Zones and ZIDs for Aquatic Life Protection” on page 70.

If no water is present upstream of the discharge, samples may be taken from a nearby perennial stream or from the nearest downstream perennial stream. Be sure to sample above the confluence with the receiving stream so that samples are not affected by the effluent pH.

• • Collect a minimum of 30 samples from the receiving water to represent a range of seasonal conditions. The applicant is responsible for providing a minimum of 30 valid data points to obtain a statistically reliable estimate of the 85th percentile value of the dissolved-to-total ratio. Samples should typically be taken a minimum of one week apart from one another.

Chloride More silver is present in free ionic form (and is therefore more toxic) in water that has low chloride concentrations. Therefore, the permit limit for silver is more stringent for facilities whose receiving water has low chloride concentrations. The TCEQ uses the 50th percentile of basin or segment chloride data to calculate the percentage of dissolved silver that is in free ionic form. Before collecting any site-specific data, it is advisable for the permittee to determine what default value was used in the TCEQ’s calculations.

The following items outline acceptable procedures for collecting site- specific chloride data:

• • Collect samples from the receiving water upstream of the discharge, if available, and outside of the regulatory mixing zone. For more information about mixing zones, see § 307.8(b) of the Standards and the section of this document entitled, “Mixing Zones and ZIDs for Aquatic Life Protection” on page 70.

If no water is present upstream of the discharge, samples may be taken from a nearby perennial stream or from the nearest downstream perennial stream. Be sure to sample above the confluence with the receiving stream so that samples are not affected by chloride concentration in the effluent.

• • Collect a minimum of 30 samples from the receiving water to represent a range of seasonal conditions. The applicant is responsible for providing a minimum of 30 valid data points to obtain a statistically reliable estimate of the 85th percentile value of the dissolved-to-total ratio. Samples should typically be taken a minimum of one week apart from one another.

TSS, Partition Coefficients, and Bioavailable Fractions of Metals For most metals, with the exceptions of mercury and selenium, the water quality criteria for aquatic life protection are expressed as dissolved concentrations. The dissolved concentration of a metal is the bioavailable fraction of the total metal concentration. The ratio of the dissolved concentration to the total recoverable concentration is expressed in terms of the partition coefficient (Kp) and TSS concentration: Cd 1  CT 1  ( K p  TSS 106 )

where: Cd = dissolved metal concentration CT = total metal concentration Kp = partition coefficient (L/kg) TSS = total suspended solids (mg/L)

The partition coefficient is itself a function of TSS concentration:

K p  10 b  (TSS ) m

where: Kp = partition coefficient (L/kg) b= intercept (found in Table 6) TSS = total suspended solids (mg/L) m= slope (found in Table 6)

Table 6 lists the slope (m) and intercept (b) values for the relationship between TSS and the partition coefficient for most metals. The TCEQ typically uses the segment-specific TSS values from the tables in Appendix D of this document along with the values and equations in Table 6 to calculate the bioavailable fraction of a metal. The bioavailable fraction is then used in the waste load allocation (WLA). For more information on WLAs, see the subsection of this document entitled “Calculating Waste Load Allocations” on page 134.

Table 6. Slope (m) and Intercept (b) Values Used to Calculate Partition Coefficients for Metals in Streams, Lakes, and Estuarine Systems STREAMS 1 LAKES 1 ESTUARINE SYSTEMS 2 METAL b m b m b m Assumed equal to Arsenic 5.68 -0.73 — — streams Cadmium 6.60 -1.13 6.55 -0.92 — —

Chromium 6.52 -0.93 6.34 -0.27 — —

Copper 6.02 -0.74 6.45 -0.90 4.85 -0.72

Lead 6.45 -0.80 6.31 -0.53 6.06 -0.85

Mercury 6.46 -1.14 6.29 -1.17 — —

Nickel 5.69 -0.57 6.34 -0.76 — — Assumed equal to Silver 3 6.38 -1.03 5.86 -0.74 streams Zinc 6.10 -0.70 6.52 -0.68 5.36 -0.52

1 Attachment I in Technical Guidance Manual for Performing Waste Load Allocations. Book II: Streams and Rivers. Chapter 3: Toxic Substances, EPA-440/4-84-022, June 1984. 2 Benoit, G., S.D. Oktay-Marshall, A. Cantu II, E.M. Hood, C.H. Coleman, M.O. Corapcioglu, and P.H. Santschi.1994. Partitioning of Cu, Pb, Ag, Zn, Fe, Al, and Mn Between Filter-Retaining Particles, Colloids, and Solution in Six Texas Estuaries. Marine Chemistry, 45:307-336. 3 Wen, L., P.H. Santschi, G.A. Gill, C.L. Paternostro, and R.D. Lehman. 1997. Colloidal and Particulate Silver in River and Estuarine Waters of Texas. Environmental Science & Technology, 31:723-731.

Permittees have some options available to them for modifying the calculation of bioavailable fractions:

• • Collect site-specific TSS data—this allows the partition coefficient to be calculated using a site-specific TSS value in place of the 15th percentile of the basin or segment values. The resulting bioavailable fraction will also be modified.
• • Collect site-specific total and dissolved metals concentrations—this allows the ratio of Cd to CT to be measured directly without calculating a revised partition coefficient.

Both of these options are discussed in more detail below.

Collect Site-Specific TSS Data The TCEQ uses the 15th percentile of basin or segment TSS data (ranked from lowest to highest value) to calculate partition coefficients. Before collecting any site-specific data, it is advisable for the permittee to

determine what default value was used in the TCEQ’s calculations. The following items outline acceptable procedures for collecting site- specific TSS data:

• • Collect samples from the receiving water upstream of the discharge, if available, and outside of the regulatory mixing zone. For more information about mixing zones, see § 307.8(b) of the Standards and the section of this document entitled, “Mixing Zones and ZIDs for Aquatic Life Protection” on page 70.

If no water is present upstream of the discharge, samples may be taken from a nearby perennial stream or from the nearest downstream perennial stream. Be sure to sample above the confluence with the receiving stream so that samples do not include TSS from the effluent.

• • Collect a minimum of 30 samples from the receiving water to represent a range of seasonal conditions. The applicant is responsible for providing a minimum of 30 valid data points to obtain a statistically reliable estimate of the 85th percentile value of the dissolved-to-total ratio. Samples should typically be taken a minimum of one week apart from one another.
• • If the permit includes whole effluent toxicity testing requirements and receiving water is used as the control, control TSS values may also be used to supplement any site-specific data that is collected. Laboratory dilution water may not be used to provide TSS data.

Collect Site-Specific Total and Dissolved Metals Concentrations Where slopes and intercepts to calculate a partition coefficient are not available in Table 6, or where a permittee wishes to develop a site-specific bioavailable fraction for a metal (but not a site-specific TSS value), the TCEQ has established the following guidelines:

• • Collect samples from the receiving water upstream of the discharge and outside the regulatory mixing zone. These samples should be mixed with the effluent at the proportion representative of the critical dilution. The critical dilution can be obtained from the TCEQ. If upstream water is not available, the critical dilution is 100%.
• • Collect a minimum of 30 valid samples from the receiving water to represent a range of seasonal conditions. The applicant is responsible for providing a minimum of 30 valid data points to obtain a statistically reliable estimate of the 85th percentile value of the dissolved-to-total ratio. Samples should typically be taken a minimum of one week apart from one another.

• • Collect samples to reflect different receiving water characteristics that exist at various times of the day and week. This may require collecting samples for a full year. If a shorter study duration is acceptable, there should be a minimum of one week between each sampling event.
• • Measure both dissolved and total recoverable metal concentrations.
• • Use clean techniques for all metals sampling and analytical procedures to avoid contamination.
• • Collect site-specific TSS data according to the procedures outlined previously.
• • Collect effluent TSS data. If effluent TSS exceeds ambient conditions, a correction factor will be applied to remove the influence of the effluent TSS on the dissolved metal concentration.
• • Once the data are collected and the ratios of the dissolved concentration to the total recoverable concentration are calculated, the ratios are ranked from lowest to highest, and the 85th percentile value is used as the bioavailable fraction when calculating the waste load allocation. (For more information on WLAs, see the subsection of this document entitled “Calculating Waste Load Allocations” on page 134.)

Aluminum The total amount of aluminum reported in a facility’s effluent is assumed to be 100% bioavailable (i.e., the partition coefficient is assumed to be 1.0) unless a permittee conducts a site-specific partition coefficient study that demonstrates otherwise. Many site-specific studies have demonstrated that aluminum in effluent is not all bioavailable (i.e., toxic to aquatic life).

To demonstrate that aluminum in the effluent is not all bioavailable, the permittee should determine the no observable effects concentration (NOEC) for total aluminum-spiked effluent using, at a minimum, three standard 48-hour acute toxicity tests employing an appropriately sensitive test species (a species from one of the three genera in the family Daphnidae, preferably Ceriodaphnia dubia).

Once a mean total-aluminum NOEC is determined, it will be compared to the proposed effluent limits calculated by using the site-specific partition coefficient in the WLA acute criteria equation. A mean NOEC significantly greater than the proposed effluent limits meets the requirement to demonstrate that the proposed aluminum effluent limits will not cause instream effects.

Aluminum in Storm Water Discharges Facilities that commingle storm water with their effluent prior to discharge or that discharge only storm water may have elevated levels of aluminum due solely to their location. The following procedure for evaluating aluminum in storm water discharges is not used for other metals because: (1) no partition coefficient is used when screening a facility’s effluent for aluminum for permitting purposes and (2) aluminum often occurs naturally in storm water discharges. If a facility experiences elevated concentrations of other metals in storm water, the permittee may pursue either a partition coefficient study or water-effect ratio study to address the issue.

If storm water is believed to be the only source of aluminum in a discharge, permittees may, after providing all of the following information, request the TCEQ to reconsider the need for aluminum limits.

• • Clearly demonstrate that aluminum is not used in the facility’s processes or added to the facility’s waste streams.
• • If storm water is commingled with facility wastewater, collect samples of storm water alone to demonstrate that aluminum levels in the storm water are directly responsible for aluminum levels reported in the commingled discharge. The number of data points needed for this demonstration will be determined on a case-by-case basis.
• • Determine the ratio of the dissolved aluminum concentration to the total recoverable aluminum concentration for the facility. If the dissolved portion of the metal is greater than 50%, the permittee may need to pursue a more traditional method (i.e., partition coefficient study or water-effect ratio study) to address the potential toxicity of aluminum in the discharge. For further information on determining dissolved-to-total ratios for metals, see the section of this document entitled “TSS, Partition Coefficients, and Bioavailable Fractions of Metals” on page 159. The number of data points necessary will be determined on a case-by-case basis.

If the information provided indicates: (1) that process water is not the source of aluminum in the storm water and (2) that the aluminum in the storm water is primarily particulate, an aluminum limit is not needed. Best management practices may be included in the permit. Permittees that prefer not to provide the information outlined above still retain the option to pursue a site-specific partition coefficient study or water-effect ratio study to determine the bioavailability of aluminum in their discharge.

Calculating Permit Limits for Specific Toxic Pollutants Calculating Permit Limits for Mercury, PCBs, Dioxins/Furans, DDT, DDD, and DDE

Converting Tissue Criteria to Water Column Criteria The water quality criteria for the protection of human health for highly bioaccumulative pollutants such as mercury, PCB, and DDT (including metabolites) are expressed as fish tissue concentrations (μg/kg) rather than as water column concentrations. In order to determine if a facility needs effluent monitoring or limits for these pollutants, the tissue criteria must be converted to water column values. This is accomplished by first converting the tissue criterion from μg/kg to mg/kg (by dividing by 1,000) and then dividing by either a BAF or BCF.

Water Column Criterion (mg/L) = Tissue Criterion (mg/kg) BAF or BCF (L/kg)

In accordance with EPA’s 2000 guidance for developing human health criteria, 13 a BAF is preferred over a BCF because the BAF includes an organism’s exposure from both diet and water, whereas the BCF includes only the organism’s exposure to water. However, EPA has used the BAF in only a few current national criteria calculations. Therefore, a BCF value may be used if no scientifically accepted BAF value is available. The table that follows lists pollutants and their assumed BCFs that will be used to translate tissue criteria to water column criteria for purposes of TPDES permitting.

Pollutant BCF (L/kg) DDT 5.36×104 DDD 5.36×104 DDE 5.36×104 Dioxin 5.0×103 Mercury 3.3×104 PCB 3.12×104

While the 2001 final EPA methylmercury criteria document 14 does develop a national BAF, Appendix A of that document explains that the scientific community did not have confidence in the BAF. The BCF of 3.3×104, which is also discussed in the final EPA criteria document, will

13 Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health, U.S. Environmental Protection Agency, Office of Science and Technology, EPA-822-B-00-004, October 2000. 14 Water Quality Criterion for the Protection of Human Health: Methylmercury, U.S. Environmental Protection Agency, Office of Science and Technology, EPA-823-R-01-001, January 2001.

be used in place of the BAF until a more reliably developed BAF can be determined.

Permittees may pursue a site-specific BAF study for any of the pollutants discussed in this section in order to better reflect conditions specific to their discharge location. Upon EPA approval, a site-specific BAF will be added to Appendix E of the Water Quality Standards. Because Texas is a very diverse state with varying geology, water chemistry, and water body types, each site-specific study would need to be discussed in detail with the TCEQ before the study is begun.

Once the tissue-based criterion has been translated to a water-column based criterion, permit limits are calculated according to the method outlined previously in the section of this document entitled “Deriving Permit Limits for Human Health Protection” on page 140.

Dioxin/Furan Congeners The TCEQ addresses the differences in the relative toxicity of dioxin/furan congeners in comparison to 2,3,7,8 TCDD and 1,2,3,7,8 PeCDD (most toxic dioxin/furan congeners) with the use of toxic equivalency factors (TEFs). The World Health Organization updated TEFs for dioxin/furans in 2005 and also included TEF values for dioxin-like PCBs. The Standards contain TEFs for fifteen congeners. The compounds and their TEFs as adopted by the TCEQ are given in the table that follows.

Compound TEF 2378 TCDD 1 12378 PeCDD 1 2378 HxCDDs 0.1 1234678 HpCDD 0.01 OCDD 0.0003 2378 TCDF 0.1 12378 PeCDF 0.03 23478 PeCDF 0.3 2378 HxCDFs 0.1 23478 HpCDFs 0.01 OCDF 0.0003 PCB 77 0.0001 PCB 81 0.0003 PCB 126 0.1 PCB 169 0.03

The concentration of each dioxin/furan compound in an effluent analysis is multiplied by the compound’s TEF. The sum of these products of concentrations and TEFs is the toxic equivalence (TEQ) of the mixture, expressed as if the toxicity were due entirely to a congener with a TEF equal to 1.0 such as 2,3,7,8 TCDD. The potential additive effects of various forms of dioxin/furans with different relative toxicities are thereby taken into account. The TCEQ evaluates compliance with appropriate dioxin/furan permit limits based on this TEQ method. Permittees that are required to monitor their effluent for dioxin/furans may also be required to sample receiving water fish tissue and/or sediments for dioxin/furans.

Calculating Permit Limits for Silver The Standards express the freshwater criterion for silver in terms of the free ionic form, which is considered to be the most biologically toxic component of dissolved silver. This section describes how the free ionic criterion is translated into a total recoverable permit limit.

Before applying the translation method, the fraction of total silver that is in the dissolved form is calculated using a partition coefficient. (For more information on calculating and using partition coefficients, see the subsection of this document entitled “TSS, Partition Coefficients, and Bioavailable Fractions of Metals” on page 159.)

For silver, the TCEQ uses partition coefficient slopes and intercepts (see Table 6 on page 159) derived from data collected by the Texas Environmental Advisory Council. In 1994, the TEAC conducted statewide sampling of various water bodies and analyzed for both total and dissolved silver concentrations and total suspended solids (TSS). This information has since been published. 15

Once the partition coefficient has been calculated, the percentage of dissolved silver in free ionic form is calculated. Data collected from a variety of water bodies throughout the United States show that a correlation exists between the dissolved chloride concentration and the percent free ionic silver. 16 Using this data, the following regression equation (r2 of 0.87) was developed to calculate the percentage of dissolved silver in free ionic form:  1     0.6659  0.0044 Cl  Y e e

15 Wen, L., P.H. Santschi, G.A. Gill, C.L. Paternostro, and R.D. Lehman. 1997. Colloidal and Particulate Silver in River and Estuarine Waters of Texas. Environmental Science & Technology, 31:723-731. 16 Water Quality Assessment: A Screening Procedure for Toxic and Conventional Pollutants in Surface and Ground Water - Part 1, U.S. Environmental Protection Agency, EPA 600/6-85-002a, 1985.

where: Y= % of dissolved silver in free ionic form e= the base of natural logarithms Cl = dissolved chloride concentration (mg/L)

In this equation, the TCEQ uses the 50th percentile value of dissolved chloride concentrations for each segment (shown in Appendix D) or for each basin if there is insufficient segment data. Site-specific data may also be used (see the subsection of this document entitled “Hardness, pH, and Chloride” on page 156).

When the 50th percentile chloride value exceeds 140 mg/L (the upper extent of the regression’s data range), the percentage of silver in the free ionic form is set at 8.98%.

Finally, the proportion of dissolved silver that is in the free ionic form is multiplied by the proportion of total silver that is dissolved to obtain the fraction available as follows (see page 159 for definitions of Cd and CT): Cd Y Fraction Available   CT 100

The fraction available is used in the waste load allocation equation. For example, if 30% of the silver is dissolved and 50% of the dissolved silver is in free ionic form, the fraction available used in the WLA equation is 0.15 (0.3 multiplied by 0.5).

Calculating Permit Limits for Chromium The Standards for the protection of aquatic life are expressed as dissolved concentrations for hexavalent chromium (Cr+6) and trivalent chromium (Cr+3). The method to calculate permit limits for total recoverable concentrations of Cr+3 and dissolved concentrations for Cr+6 is described in this section.

As part of the permit application, permittees analyze their effluent for dissolved Cr+6 and total recoverable chromium. Total recoverable chromium is the sum of dissolved Cr+6, adsorbed Cr+6, dissolved Cr+3, and adsorbed Cr+3:

total recoverable Cr = dissolved Cr+6 + adsorbed Cr+6 + dissolved Cr+3 + adsorbed Cr+3

The analytical method for Cr+6 measures only for the dissolved form. The TCEQ assumes that the amount of adsorbed Cr+6 is negligible. Therefore, total Cr+3 is calculated by subtracting dissolved Cr+6 from the total recoverable chromium:

total Cr+3 = total recoverable Cr – dissolved Cr+6

The slope and intercept values for chromium, listed in Table 6 on page 159, are not applicable to Cr+6 because dissolved concentrations alone are measured. Therefore, the Cr+6 permit limit is calculated using standard procedures and assuming 100% of Cr+6 is dissolved. The effluent concentration is compared to the calculated permit limit to determine whether monitoring or permit limits are needed.

The slope and intercept values in Table 6 and standard procedures are used to calculate Cr+3 permit limits. The calculated permit limit is compared to the total Cr+3 concentration in the effluent to determine whether monitoring requirements or permit limits are needed.

The slope and intercept values in Table 6 and standard procedures are used to calculate chromium limits for the protection of human health. The permit limit is expressed as total recoverable chromium.

Establishing Permit Limits for Toxic Pollutants Application Screening TCEQ staff calculate daily average and daily maximum effluent limits required to maintain the surface water quality standards based upon the instream criteria established in § 307.6 (c) and (d) of the Standards. During the application review, the effluent data provided in the application are compared to the calculated daily average effluent limits.

• • If the effluent data are based on one sample and the effluent concentration for a pollutant equals or exceeds 70% of the calculated daily average effluent limit, the TCEQ may request the applicant to either: (1) submit historical data or; (2) resample and conduct additional analysis for that particular pollutant using four effluent samples. Samples should either be all composites or all grabs, as appropriate.
• • If the effluent data submitted with the application are based on four samples, additional sampling is not typically requested.

Sometimes the effluent analysis contains one or more samples that have reported nondetectable levels of a pollutant. (Nondetectable levels are the “<” values in laboratory reports.) When this occurs in all four resamples and the reported nondetectable levels are equal to or less than the TCEQ’s minimum analytical level (MAL), the TCEQ will use a zero for each value. If the four retests have both detectable and nondetectable concentrations at or below the TCEQ’s MAL, then the nondetectable

concentrations are averaged as one-half the reported nondetectable levels, and the detectable concentrations are averaged as their reported values.

The average concentration of the effluent data is then compared to the daily average effluent limit.

• • If the average of the effluent data equals or exceeds 70%, but is less than 85% of the calculated daily average limit, monitoring for the toxic pollutant will usually be included as a condition in the permit.
• • If the average of the effluent data is equal to or greater than 85% of the calculated daily average limit, the permit will generally contain effluent limits for the toxic pollutant. The permit may specify a compliance period to achieve this limit if necessary.

If a toxic pollutant is quantified below the MAL and equals or exceeds 70% of the calculated daily average permit limit, the applicant may be required to submit historical data or to retest as described above. The applicant may also be required to establish a site-specific MAL for the effluent.

Analytical Procedures and MALs As required by 30 TAC § 319.11, all analyses of effluents must meet the requirements specified in the regulations published in 40 CFR Part 136 or the latest edition of Standard Methods for the Examination of Water and Wastewater (Standard Methods). If any regulated pollutant is not included in 40 CFR Part 136 or Standard Methods, the permittee may use a TCEQ- recommended analytical method or a method approved for the specific compound in water or wastewater by the EPA. All quality assurance/quality control practices must strictly adhere to those outlined in each EPA-approved analytical method.

Applicants and Permittees may transfer an analyte from one EPA- approved method to another EPA-approved method as described on pages 6-2 and 6-3 of the EPA document Analytical Method Guidance for the Pharmaceutical Manufacturing Point Source Category, EPA 821-B-99-003 (August 1999) (See Appendix G). Such authorization is not intended to be limited to pharmaceutical manufacturing and may be undertaken by any applicant or permittee for any analyte as long as applicable NELAC accreditation for the analyte is obtained.

The following terms are used to quantify sensitivity of analytical test procedures:

In 40 CFR Part 136 Appendix B, the method detection limit (MDL) is defined as the minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is greater

than zero; it is determined from the analysis of a sample in a given matrix containing the analyte.

In the Standards, the minimum analytical level (MAL) is defined as the lowest concentration at which a particular substance can be quantitatively measured with a defined accuracy and precision level, using approved analytical methods. The MAL is not the published MDL for an EPA- approved analytical method, which is based on a single laboratory analysis of the substance in reagent (distilled) water. The MAL is based on analyses of the analyte in the matrix of concern (that is, wastewater effluents).

The TCEQ will establish general MALs that are applicable when information on matrix-specific MALs are unavailable. General MALs are established in this document for use in effluent testing. See Table E-1 in Appendix E for general MALs for permit application screening. See Table E-2 in Appendix E for MALs and analytical methods for the determination of pollutants regulated by § 307.6 of the Standards.

The MALs were developed by the TCEQ to establish a benchmark for analytical procedures for measuring the toxic pollutants regulated by § 307.6 of the Standards. One of the goals of establishing the MALs is to provide consistent analytical data for industrial and domestic wastewater permit applicants and compliance monitoring of their discharges. The MALs serve as a measure of the analytical sensitivity of each laboratory procedure performed on standard laboratory equipment by qualified personnel.

The MALs developed in Tables E-1 and E-2 were derived by evaluating all of the 40 CFR Part 136 EPA-approved methods and selecting the most stringent detection level achievable from each approved method in reagent water. The purpose of establishing TCEQ-approved MALs is to identify the minimum detectable concentration for which an analytical method exists. The methods identified in Tables E-1 and E-2 are the methods used to develop the corresponding MAL.

By establishing MALs, TCEQ is not requiring use of the corresponding analytical test method, nor is TCEQ requiring analytical results to be submitted where the laboratory test was run to achieve this MAL. For permitting and compliance purposes, MALs are used to allow an applicant or permittee to submit analytical results as nondetect. Nondetect analytical results are assumed to represent a concentration of zero (0) mg/L (or µg/L as appropriate).

When an MAL in Table E-1 or E-2 cannot be achieved with the analytical method identified in Table E-1 or E-2 for that analyte due to matrix interferences that are documented by the laboratory and identified as limitations in the analytical method (for example, when a metals sample must be diluted because the inorganic TDS concentration exceeds 2,000 mg/L), the TCEQ may approve use of the higher MAL as the lowest achievable MAL for that effluent matrix. In such cases, a permit would allow reporting nondetect analytical results as zero (0).

Applicants and permittees may apply for a matrix-specific MAL when they cannot achieve the MAL in Table E-1 or E-2 and the specific matrix interference is not identified in the approved analytical method (see page 172). An example of when a matrix-specific MAL may be requested is for one or all of the cyanide methods identified in Table E-1 or E-2. Cyanide species are a method-defined analyte, and as such, may be subject to unidentifiable interferences which elevate the MAL above the applicable Table E-1 or E-2 concentrations. When a matrix-specific MAL that is greater than the MAL in Table E-1 or E-2 is approved by the TCEQ for an analyte, the permit will allow the permittee to report nondetect analytical results as zero (0). A permittee may apply for a matrix-specific MAL when it files its application or at any time during the life of the permit.

The MALs in Tables E-1 and E-2 are not applicable to untreated, or partially treated, municipal and industrial wastewaters. Untreated and partially treated process-type wastewaters often have high concentrations of pollutants that require dilution of samples prior to analysis.

For various pollutants in the Standards, the hazardous metals limits at 30 TAC 319, Subchapter B, and in the EPA’s national categorical effluent limitations guidelines and pretreatment standards, permitting and compliance decisions may not require submittal of analytical results at the MALs identified in Tables E-1 and E-2. Applicants and permittees may use any analytical method approved in 40 CFR Part 136 that is sufficiently sensitive to demonstrate compliance with their numeric permit limits (mass and concentration). Analytical test results that are submitted as nondetect at a laboratory reporting level higher than the MAL in Tables E- 1 or E-2 will be treated and evaluated as if the analyte was detected at one- half the reported LOQ value.

The following example discusses a typical situation where using an analytical test method that does not achieve the MAL identified in Tables E-1 or E-2 would be acceptable and result in no adverse permitting or compliance issues for an applicant/permittee.

Example:

For aluminum, the TCEQ has established a freshwater acute criterion of 991 µg/L. Assuming no instream dilution and using procedures previously discussed in this chapter, the permit writer calculates a daily average effluent limit of 834.73 µg/L. The TCEQ screening procedures (see page 163) evaluate the need for monitoring a pollutant at 70% of the calculated daily average effluent limit, resulting in a screening level of 584.31 µg/L.

The test method established for aluminum in Table E-1 or E-2, EPA Method 200.8, has an associated MAL of 5 µg/L. However, test method SM3113B* exists and can achieve a Level of Quantitation (LOQ) of 20 µg/L. Test method SM3113B is used and the laboratory reports nondetect at the associated LOQ of 20 µg/L. The TCEQ will evaluate this analytical result as a detection at one-half the LOQ, 10 µg/L. Comparing the 10 µg/L reported result against the 584.31 µg/L screening level would result in no monitoring requirement or effluent limit for aluminum in this permit.

*SM = Standard Methods for the Examination of Water and Wastewater

Effective Date of Revised MALs MALs and Suggested Analytical Methods listed in Appendix E, will be implemented on the 365th day following commission approval of this document for reissuance of any TPDES permit, wastewater application screening, or pretreatment program monitoring.

Alternate Test Procedures Because of interferences and matrix problems associated with the analysis of toxic pollutants in wastewater, the TCEQ has received requests for the use of alternate analytical test method procedures. The procedures may range from an alteration of an EPA-approved reference method to a completely new or “candidate” method. Guidelines are given below for accepting or rejecting those alternate test procedures for compliance monitoring of TPDES permits.

If a permittee wishes to initiate the evaluation process for an alternate analytical test method procedure, the permittee may send a written request for authorization to the Quality Assurance Manager and/or the Section Manager of the Wastewater Permitting Section. The request must include details required by 30 TAC § 319.12 and may be subject to accreditation requirements in 30 TAC Chapter 25, Subchapters A and B, as amended. The information required in 40 CFR Part 136.4(c) (Application for Alternate Test Procedures) should also be submitted. All candidate methods should undergo a comparability study. A comparability study should compare the performance of the alternate or candidate analytical method to an EPA-approved reference method.

If the permittee cannot attain the MAL for a specific pollutant and has exhausted all available techniques to solve interference and matrix problems, the permittee may apply for an alternate MAL through the same procedure used to request an alternate analytical test method, provided that all documentation of attempted solutions to the interference/matrix problems is included with the application. This documentation needs to include all quality assurance/quality control data. Alternate test procedures are subject to review and approval by EPA.

Defining Permit Limits Permit limits are normally developed from total recoverable concentrations. The permit limit is expressed as the calculated daily average and daily maximum concentration and/or the daily average and daily maximum mass loading.

If the permit limit is lower than the MAL, it is still included in the permit, but a level of compliance based on the MAL is also included except where a substance is of particular concern (for example, if the toxicant has a high bioconcentration factor). If the TCEQ believes it is necessary to establish a permit level of compliance below the MAL, the permittee will be required to develop an effluent-specific MDL.

When necessary, the permit applicant may request an opportunity to demonstrate an alternative site-specific MAL for the effluent to account for interfering factors associated with the wastewater in question. See the discussion for requesting an alternate MAL through the alternate analytical test method procedure in the previous subsection of this document entitled “Alternate Test Procedures” (see page 172).

When establishing monitoring frequencies, TCEQ staff use 30 TAC 319 and TCEQ guidance established in document number 98-001.000-OWR- WQ, “Guidance Document for Establishing Monitoring Frequencies for Domestic and Industrial Wastewater Discharge Permits,” May 1998.

Screening Procedures and Permit Limits for Total Dissolved Solids

Introduction Concentrations and relative ratios of dissolved minerals such as chloride and sulfate that compose total dissolved solids (TDS) will be maintained to protect existing and attainable uses. The aquatic life attributes in § 307.7(b)(3)(A) of the Standards are used to assign the aquatic life use categories.

Applicability The screening procedure will be applied to all domestic dischargers that have an average permitted flow of ≥ 1 MGD, all industrial majors, and industrial minors on a case-by-case basis.

Discharges to Freshwater For discharges to freshwater, a screening procedure is used to determine whether either a TDS permit limit or further study of the receiving water is required. Screening may also be performed for individual components of TDS, including chloride and sulfate, since these anions have specific numerical criteria in the Standards. If screening demonstrates elevated levels of TDS, then appropriate permit limits are calculated.

Discharges to Saltwater For discharges to saltwater, TDS is evaluated on a case-by-case basis. Even though salinity criteria have not been established, the absence of numerical criteria does not preclude evaluations and regulatory actions based on estuarine salinity. Careful consideration is given to all activities that may detrimentally affect estuarine salinity gradients.

Wastewater Recycling Certain facilities reduce water consumption by recycling their wastewater before discharge, which may increase the effluent TDS concentration. The procedures in this chapter will be applied to such facilities to ensure protection of water quality.

Overview of Procedures The general procedure for screening TDS concentrations in permit applications and then developing permit limits is as follows:

1. Select the appropriate screening procedure for the receiving water type. A detailed discussion begins on page 175 in the section entitled “Screening Procedures for TDS.”

2. Perform the screening calculation or calculations.

3. If the screening criteria are exceeded, calculate effluent TDS concentrations using the appropriate method for the receiving water type. A detailed discussion begins on page 182 in the section entitled “Establishing Permit Limits for TDS.”

4. Compare the effluent TDS concentrations obtained in step 3 with the calculated effluent limits using the 70%, 85% procedure (see the section of this document entitled “Application Screening” on page 168) to determine whether a monitoring requirement or effluent limit is needed in the permit.

5. If necessary, place monitoring or effluent limits in the permit.

Screening Procedures for TDS The following screening procedures are typically used by TCEQ staff to assess TDS in wastewater discharges to various water body types. See Table 7 on page 185 for a summary of screening methods as they apply to different types of water bodies. Screening using TDS will normally be sufficient to address dissolved minerals. In unusual situations where ionic ratios are substantially skewed, screening can also be conducted for chloride or sulfate.

1a. Unclassified Intermittent Stream―TDS Use Equation 1a (below) to determine the TDS screening value, CSV, for a discharge to an unclassified intermittent stream without perennial pools. The effluent TDS concentration, CE, as reported in the permit application, will be compared to the screening value to determine whether a TDS permit limit is needed.

Equation 1a

where: CTDS = TDS concentration (mg/L) used to determine the TDS screening value CC = TDS criterion (mg/L) at the first downstream segment 500 mg/L = median concentration of TDS in Texas streams 2,500 mg/L = minimum TDS screening value

If the value of CTDS in Equation 1a is less than 2,500 mg/L, then 2,500 mg/L is used as the screening value. If CTDS is between 2,500 mg/L and 6,000 mg/L, then CTDS is used as the screening value. If CTDS is greater than 6,000 mg/L, then 6,000 mg/L is used as the screening value unless the applicant demonstrates that a higher TDS value is more representative of the receiving stream. The following table summarizes the conditions in this paragraph.

If CTDS then CSV = ≤ 2,500 mg/L 2,500 mg/L > 2,500 mg/L but ≤ 6,000 mg/L CTDS > 6,000 mg/L 6,000 mg/L

In addition, some specific types of intermittent streams have alternative default screening values. These stream types and screening values are summarized in the following table:

Other Specific Types of Intermittent If CTDS then CSV = Streams Intermittent streams that are demonstrated < 4,000 mg/L 4,000 mg/L to be dry except for very short-term flow ≥ 4,000 mg/L CTDS in immediate response to rainfall Constructed ditches that convey storm < 4,000 mg/L 4,000 mg/L water and/or wastewater effluent that are ≥ 4,000 mg/L CTDS considered water in the state Intermittent streams that enter tidal waters ― 6,000 mg/L within three miles of the discharge point

TDS screening guidelines for intermittent streams are intended to protect livestock, wildlife, shoreline vegetation, and aquatic life during periods when the stream is flowing; the screening is also intended to preclude excessive TDS loading in watersheds that could eventually impact distant downstream perennial waters.

1b. Unclassified Intermittent Stream―Chloride and Sulfate Chloride (Cl) and sulfate (SO4) will not typically be screened for discharges to intermittent streams because the TDS screening should be adequately protective. However, for situations where TDS screening alone may not provide adequate protection, similar screening may be performed for chloride and sulfate. After determining the TDS screening value as discussed in 1a, use Equation 1b (below) to determine the chloride and sulfate screening values (CSV). The effluent chloride and sulfate concentrations reported in the permit application will be compared to the screening values to determine whether a chloride or sulfate permit limit or monitoring is needed.

Equation 1b TDS C SV Cl or SO4 C SV   Cl or SO4 Criterion TDS Criterion

2. Unclassified Perennial Stream or River Screen for TDS using Equation 2 (below), which compares the concentration of TDS at the edge of the human health mixing zone downstream of the discharge (right side of equation) with the TDS criterion (CC) for the first downstream segment (left side of equation). A permit limit is usually not required when Equation 2 is satisfied (that is, CC ≥ right side of equation).

QS C A  Q E C E CC  Equation 2 Q E  QS

where: CC = segment TDS criterion (mg/L) QS = harmonic mean flow (ft3/s) of the perennial stream or river CA = ambient TDS concentration (mg/L) QE = effluent flow (ft3/s) CE = effluent TDS concentration (mg/L)

The following items explain the variables used in Equation 2:

CC The TDS criterion for the first downstream segment is found in Appendix A of the Standards. If the permittee wishes to change the segment TDS criterion, an intensive study is needed. Such a study involves sampling the entire classified segment during different seasons. A site-specific amendment to the Standards is then needed to change the TDS segment criterion.

QS The harmonic mean flow is determined as described in the section of this document entitled “Determining the Harmonic Mean Flow” on page 80.

CA The ambient TDS concentration is the median (50th percentile) concentration of TDS for the first downstream segment. Sources for determining the median TDS concentration include: (1) the tables in Appendix D of this document; (2) the most recent five years of TDS data in the Surface Water Quality Monitoring Information System (SWQMIS) database; or (3) other available data. The permittee may supply site-specific data if the median TDS concentration for the first downstream segment does not appear to be representative of the TDS concentration in the receiving water.

QE The effluent flow used is generally the average permitted flow for domestic discharges and the average of the monthly average flows for the last two years for industrial discharges.

CE The effluent TDS concentration is based on the average effluent data provided in the permit application.

3. Classified Stream or River Screen for TDS using Equation 2. Use the harmonic mean flow (QS) of the classified segment, and use the median TDS value for the classified segment as the ambient concentration (CA). A permit limit is usually not required when Equation 2 is satisfied (that is, CC ≥ right side of equation).

4. Unclassified Intermittent Stream within 3 Miles of a Perennial Freshwater Body a. Screen for TDS at the intermittent stream as described in item 1. b. Screen for TDS at the perennial freshwater body using the appropriate protocol described in item 2, 3, 6, or 7. c. Compare the screening values from (a) and (b) and use the more stringent one.

Freshwater bodies more than 3 miles downstream of the discharge may be evaluated if they contain a drinking water supply or aquatic life that is particularly sensitive to increases in TDS.

5. Unclassified Intermittent Stream with Perennial Pools a. Screen for TDS as described in item 1. b. Screen for TDS using Equation 2 using the harmonic mean flow (QS) for the intermittent stream with perennial pools. c. Compare the screening values from (a) and (b) and use the more stringent one.

6. Classified Lake Screen for TDS using Equation 3 (below), which compares the concentration of TDS at the edge of the human health mixing zone (right side of equation) with the TDS criterion (CC) for the segment (left side of equation). A permit limit is usually not required when Equation 3 is satisfied (that is, CC ≥ right side of equation).

Equation 3 CC  ( E F )(C E )  (1  E F )(C A )

where: CC = segment TDS criterion (mg/L) EF = effluent fraction at the edge of the human health mixing zone CE = effluent TDS concentration (mg/L) CA = ambient TDS concentration (mg/L)

The following items explain the variables used in Equation 3:

CC The TDS criterion for the segment is found in Appendix A of the Standards. If the permittee wishes to change the segment TDS criterion, an intensive study is needed. Such a study involves sampling the entire classified lake during different seasons. A site-specific amendment to the Standards is then needed to change the TDS segment criterion.

EF The effluent fraction at the edge of the human health mixing zone is calculated as described in the section of this document entitled “Mixing Zones and Critical Conditions for Human Health Protection” on page 78.

CE The effluent TDS concentration is based on the average effluent data provided in the permit application.

CA The ambient TDS concentration is the median (50th percentile) concentration of TDS for the segment. Sources for determining the median TDS concentration include (1) the tables in Appendix D of this document; (2) the most recent five years of TDS data in the Surface Water Quality Monitoring Information System (SWQMIS) database; or (3) other available data. The permittee may supply site-specific data if the median TDS concentration for the entire segment does not appear to be representative of the TDS concentration in the vicinity of the discharge.

The secondary maximum contaminant levels for drinking water (given at 30 TAC §§ 290.101 - 290.119) are considered for use as CC if the lake is a public water supply.

7. Unclassified Lake Screen for TDS using Equation 3. Differences between screening procedures for unclassified lakes compared to classified lakes are as follows:

CC The criterion for TDS from the nearest appropriate segment is used.

CA TDS or converted conductivity data (using a conversion factor of 0.65) from the unclassified lake may be used to determine CA. If such data are unavailable, use the ambient TDS concentration (median) from the nearest appropriate segment. Sources for determining the median TDS concentration include (1) the tables in Appendix D of this document; (2) the most recent five years of TDS data in the Surface Water Quality Monitoring Information System (SWQMIS) database; or (3) other available data. The permittee may supply site-specific data if the median TDS concentration from the nearest appropriate segment does not appear to be representative of the TDS concentration in the receiving water.

The secondary maximum contaminant levels for drinking water (given at 30 TAC 290.101 - 290.119) are considered for use as CC if the lake is a public water supply.

8. Bay or Wide Tidal River Compare the effluent TDS concentration to the segment TDS median and maximum. Sources for determining the median and maximum TDS concentrations include: (1) the tables in Appendix D of this document; (2) the most recent five years of TDS data in the Surface Water Quality Monitoring Information System (SWQMIS) database; or (3) other available data. Tidal waters will be protected from the adverse effects of excessively high or excessively low salinities (compared to the normal salinity range of the receiving water). The absence of numerical criteria will not preclude evaluations and regulatory actions to protect estuarine salinity.

Determining Site-Specific Ambient TDS Values High levels of TDS in an existing discharge may be justified occasionally due to elevated levels of TDS in the receiving water. In this case, the permittee has the option to submit information demonstrating that higher ambient levels of TDS exist in the receiving water and/or segment. This information can then be used to derive a site-specific ambient TDS concentration (CA).

In order to satisfy the statistical requirements for site-specific data collection, 50 TDS values should be collected over the course of one year. TCEQ staff may allow applicants to monitor conductivity and convert it to TDS using a factor of 0.65. In streams and rivers, samples should be collected upstream of an existing discharge or in a separate, nearby reference stream. In lakes and reservoirs, samples should be collected at least 500 feet from any discharge point. Equation 2 or 3 is re-evaluated if a site-specific ambient TDS concentration (CA) is approved (see Figure 11 on page 182).

If the permittee wishes to change the segment TDS criterion, a more intensive study is needed. Such a study involves sampling the entire segment under various flow regimes and seasons. A site-specific amendment to the Standards is then needed to change the TDS segment criterion.

Establishing Permit Limits for TDS If the screening criteria are exceeded and site-specific data are either not proposed or not justified, a TDS permit limit is calculated for the discharge. Similar procedures may be followed for individual constituents of TDS (that is, sulfate and chloride) if they are determined to be of concern. See Table 7 on page 185 for a summary of permit limit calculation methods as they apply to different types of water bodies.

Unclassified Intermittent Streams For discharges to unclassified intermittent streams, if the average effluent concentration of TDS in the permit application (or other available effluent data) is greater than the screening value determined using Equation 1a, then TCEQ staff considers effluent control measures for TDS.

When a limit is appropriate, the screening value or other appropriate site- specific value may be used as the daily average effluent limit for TDS. The daily maximum effluent limit for TDS is generally 2.12 times the daily average limit. The 2.12 multiplier is the ratio of the multipliers used to convert the human health LTA to daily maximum and daily average permit limits. See the section of this document entitled “Deriving Permit Limits for Human Health Protection” on page 140.

Use Equation 1a, 2, or 3 to screen effluent data in permit application.

Will discharge exceed instream No No limits required. criterion based on Equation 1a, 2, or 3?

Yes

Does discharge exceed instream criterion based on No No limits required. Equation 1a, 2, or 3 using site-specific data?

Yes

Impose permit limits derived from Equation 4 or 5 using site-specific data.

Figure 11. Establishing Permit Limits for Total Dissolved Solids

Perennial Streams and Rivers and Intermittent Streams with Perennial Pools For discharges to perennial streams and rivers or to intermittent streams that have perennial pools, Equation 4 is used to calculate the effluent TDS concentration that is used to determine TDS permit limits: (CC )(QE  QS )  (QS )(C A ) Equation 4 CE  QE

where: CE = calculated effluent TDS concentration (mg/L) CC = segment TDS criterion (mg/L) QE = effluent flow (ft3/s) QS = harmonic mean flow (ft3/s) of the receiving water or first perennial water body downstream of the discharge CA = ambient TDS concentration (mg/L)

Lakes For discharges to lakes, Equation 5 is used to calculate the effluent TDS concentration that is used to determine TDS permit limits:

CC  (1  EF )(C A ) Equation 5 CE  EF

where: CE = calculated effluent TDS concentration (mg/L) CC = segment TDS criterion (mg/L) EF = effluent fraction at the edge of the human health mixing zone CA = ambient TDS concentration (mg/L)

If either Equation 4 or 5 produces a negative value for CE, then CE is set equal to the segment TDS criterion (CC) in the absence of additional information.

Final Calculations for Lakes, Perennial Streams and Rivers, and Intermittent Streams with Perennial Pools The calculated effluent TDS concentration (CE) from Equation 4 or 5 is the annual average TDS concentration from which daily average and daily maximum permit limits may be determined. These limits are calculated by considering CE to be a waste load allocation (WLA) averaged over 365 days and calculating a long-term average (LTA) effluent concentration. This procedure is outlined in the section of this document entitled “Deriving Permit Limits for Human Health Protection” on page 140.

In cases where the TDS concentration can be controlled by the process, such as in cooling tower operations, the usual permitting assumption that the coefficient of variation (CV) equals 0.6 may be evaluated and adjusted as appropriate.

Final Evaluation and Additional Considerations for TDS Preliminary effluent limits are evaluated to determine whether monitoring requirements, specific effluent limits, or other permit conditions are needed to address TDS (or sulfate or chloride).

Measured effluent concentrations are compared to the calculated daily average effluent limit as described in the section of this document entitled “Establishing Permit Limits for Toxic Pollutants” on page 168. Monitoring requirements are established if the measured effluent concentration exceeds 70% of the calculated daily average limit. Effluent limits are established if the measured effluent concentration exceeds 85% of the calculated daily average limit, unless all of the following conditions are met:

• • The effluent concentration of TDS is comparable to the water supply source; or, for domestic discharges, any elevations of salinity are small and typical of such discharges.
• • The water supply source is typical of TDS concentrations of surface waters in the area but does not include brine water that is produced during the extraction of oil and gas, or other sources of brine water that are substantially uncharacteristic of surface waters in the area of discharge.
• • For industrial discharges, there are no internal discharges of process water that result in a significant elevation of TDS in the external discharge compared to source water. For domestic discharges, there are no identifiable industrial discharges to the sewerage system that cause a significant elevation of TDS compared to source water.
• • The discharge will not result in significant increases in instream concentrations of chloride that would exceed EPA’s aquatic life toxic criteria for chloride (as of December 1, 1999), which are 860 mg/L acute criteria and 230 mg/L chronic criteria. This condition does not apply when EPA’s criteria are lower than: (1) applicable numerical criteria in the Standards or (2) typical concentrations of surface waters in the area.

If the above conditions are met, the permit will require instream monitoring if the discharge at permitted discharge flow is predicted to cause numerical criteria for TDS, chloride, or sulfate to be exceeded in a classified segment listed in Appendix A of the Standards. Instream

monitoring will typically consist of monthly sampling at: (1) a site in the receiving water body that is not affected by the discharge (for example, upstream of the discharge); and (2) a site in the receiving water that is affected by discharge (for example, downstream of the designated mixing zone).

If the above conditions are met for a domestic discharge, but the elevation in TDS in the effluent (compared to source water) is greater than “typical,” then the permit will contain a requirement for the permittee to develop and implement a plan to identify and reduce sources of TDS to the extent practical consistent with a sound environmental management program. However, the resolution may not cause or contribute to a violation of the TCEQ narrative criteria for the protection of aquatic life.

Additional general considerations that might indicate an effluent limit for TDS is not required include (but are not limited to) the following:

• • For a water body that does not attain numerical criteria for TDS, the discharge does not contribute to the nonattainment. For example, the source water for the discharge is from the same water body, and the discharge does not increase the source water concentration.
• • The discharge is intermittent (such as a wet-weather discharge), and the anticipated instream impacts may be evaluated using more applicable screening calculations.
• • Reductions in TDS are not economically attainable, and the discharge does not result in a violation of numerical criteria for TDS for the appropriate classified segment in Appendix A of the Standards.
• • The discharge is demonstrated to not adversely affect aquatic life and other applicable uses. This provision is only applicable if a protocol for this demonstration is approved by the TCEQ. EPA will review any protocol for this demonstration that could affect permits or other regulatory actions that are subject to EPA approval.

When a discharge exceeds the screening criteria, the general considerations in this subsection that preclude an effluent limit are noted in the permit’s fact sheet, statement of basis/technical summary, or other publicly available information. More stringent TDS limits may be required to protect unclassified spring-fed streams, streams with unique uses, or other unclassified water bodies where the aquatic life is particularly sensitive to increases in TDS. The antidegradation provisions in § 307.5 of the Standards and in the chapter of this document entitled “Antidegradation” (see page 55) are also applicable.

Table 7. Summary of TDS Screening and Limit Calculation Methods Water Body Screening Method Limit Calculation Method Type Intermittent If CE < CSV, a TDS limit is usually not required, CE = CSV, or stream where: (see page 175) CE = other appropriate site- CSV = 2,500 mg/L if CTDS ≤ 2,500 mg/L, specific value. CSV = CTDS if 2,500 mg/L < CTDS ≤ 6,000 mg/L, CSV = 6,000 mg/L if CTDS > 6,000 mg/L.

CTDS = (CC) (2,500 mg/L) 500 mg/L

See page 176 for exceptions to these values. Perennial stream If CC ≥ QSCA + QECE , CE = (CC)(QE + QS) - (QS)(CA) (see page 177 and QE + QS QE page 178) a TDS limit is usually not required. Intermittent If CE < CSV and CC ≥ QSCA + QECE , CE = CSV, or stream within QE + QS three miles of a CE = (CC)(QE + QS) - (QS)(CA) perennial stream a TDS limit is usually not required, where: QE (see page 178) or CSV = 2,500 mg/L if CTDS ≤ 2,500 mg/L, or CSV = CTDS if 2,500 mg/L < CTDS ≤ 6,000 mg/L, CE = other appropriate site- CSV = 6,000 mg/L if CTDS > 6,000 mg/L. specific value, Intermittent whichever is stream with CTDS = (CC) (2,500 mg/L) smaller. perennial pools 500 mg/L (see page 178) See page 176 for exceptions to these values. Lake If CC ≥ (EF)(CE) + (1 - EF)(CA), CE = CC - (1 - EF)(CA) (see page 179 and EF page 180) a TDS limit is usually not required. Bay or wide tidal Compare CE to median and maximum segment TDS Avoid adverse effects of river concentrations. excessively high or excessively (see page 180) low effluent TDS concentrations.

TPDES Storm Water Permits

General Provisions This chapter describes storm water discharges subject to TPDES permit requirements, which include discharges associated with industrial activities, discharges from construction activities, and discharges from municipal separate storm sewer systems (MS4s). These types of discharges are identified by state and federal regulation (30 TAC § 281.25(4) and 40 CFR Part 122).

Currently, the TCEQ has not developed routine procedures for setting chemical-specific effluent limits on storm water discharges, based upon the Standards. In certain circumstances such as industrial storm water discharges, technology-based effluent limits for storm water discharges will be applied in individual permits and general permits. The TCEQ may require an operator of an industrial facility, authorized by a general permit, to apply for an individual TPDES permit because of:

• • a total maximum daily load (TMDL) and TMDL implementation plan; • the anti-backsliding policy—see 40 CFR Part 122.44(l); • a history of substantive noncompliance; or • other site-specific considerations.

Reviewing Permit Applications Permit application review procedures for storm water discharge activities are described in this section. These procedures are different from the permit application review procedures associated with wastewater discharges (discussed in the subsection of this document entitled “Application Screening” on page 168) because storm water discharges are normally intermittent and occur during wet weather conditions.

As stated in § 307.8(e) of the Standards, controls on the quality of permitted storm water discharges are largely based on implementing best management practices and/or technology-based limits in combination with instream monitoring to assess standards attainment and to determine whether additional controls on storm water are needed. Consistent with the approach described in the EPA’s Interim Permitting Approach guidance (61 FR 43761, November 6, 1996), incorporation of effluent limits based on water quality criteria in storm water permits is based on the following items:

• • Specific conditions or limitations are incorporated as conditions of the discharger’s TPDES permit, as necessary and appropriate, based upon surface water quality data or other acceptable information.
• • Where data are not available to characterize the quality of storm water and the receiving water, the TPDES permit may include specific conditions for instream and outfall monitoring. In this situation, data collection will supplement the implementation of necessary controls. This data will be used to make any necessary permit modifications. Additionally, the data will be used to consider necessary permit revisions at the time of permit renewal. In subsequent permit actions, the TCEQ may continue to require instream and monitoring requirements, as appropriate.

Special circumstances may warrant a review similar to that applied to wastewater discharges. Some examples include:

• • Storm water management systems designed to retain water and to discharge during static or low-flow conditions.
• • Storm water management systems designed to commingle storm water with other waste streams, such as process, utility, or sanitary wastewater.

The Clean Water Act (CWA) §§ 301, 304, and 401 (33 United States Code (U.S.C.) 1331, 1314 and 1341) provide that National Pollutant Discharge Elimination System (NPDES) permits must include effluent limitations requiring authorized discharges to:

• • meet standards reflecting levels of technological capability;
• • comply with EPA-approved state water quality standards; or
• • comply with other state requirements adopted under authority retained by states under CWA § 510, 33 U.S.C. § 1370.

In general, TPDES storm water permits do not contain numerical effluent limits based on water quality criteria. Instead, they emphasize requirements that facilities must prevent or effectively reduce exposure of storm water to pollution (for example, by building shelters that protect materials and activities in general from exposure to the elements, including rainfall and rainfall runoff). Such permit requirements are similar to those of previously issued NPDES storm water permits that are based on a strategy of reducing pollution at the source, as opposed to treatment before discharge. However, nothing in this document precludes the TCEQ from assigning effluent limits based on water quality criteria to a storm water discharge.

Site-Specific Information Site-specific information may be used to develop unique storm water management practices associated with a storm water drainage system. Conditions and effluent limits may be based on, but are not limited to, the following considerations:

• • the existing storm water system design;
• • local climatic conditions;
• • the water body being listed on the state’s Clean Water Act Section § 303(d) List;
• • assessments of habitat and biological integrity of receiving waters;
• • extent of success already achieved in preventing and minimizing storm water pollution;
• • preferences and alternatives provided by the permit applicant; and
• • economically achievable and feasible measures for pollution reduction, including application of structural controls, treatment facilities, management practices and operational methods, and similar considerations.

Such information may be found in a storm water pollution prevention plan (SWP3), a storm water management plan, or a storm water management program (SWMP) for TPDES applicants. These plans or programs are documents prepared by the permit applicant describing how the site will be managed to prevent or significantly reduce discharge of pollutants from the site. These plans will be updated when necessary and made readily available to TCEQ personnel upon request.

Antidegradation Review of Storm Water Permits Antidegradation reviews of TPDES permit applications for storm water discharges are conducted in accordance with § 307.5 of the Standards. Antidegradation reviews are conducted both for individual permits (such as MS4s and specific industrial facilities) and for general permits developed to address storm water discharges from small MS4s and categories of industrial activity (including construction activity).

Discharges to Impaired Waters New sources or new discharges of the constituent or constituents of concern to impaired waters may not be authorized by a general storm water permit unless otherwise allowable under 30 TAC Chapter 305

(“Consolidated Permits”) and applicable state law. For discharges not eligible for coverage under a general storm water permit, the discharger must apply for and receive an individual or other applicable general TPDES permit authorization prior to discharging.

Impaired waters are those that do not meet one or more of the applicable water quality standards and that are listed on the state’s § 303(d) List.

Constituents of concern are those for which the water body is listed as impaired.

A discharge of the constituent or constituents of concern to impaired water bodies for which there is a TMDL or TMDL implementation plan is only eligible for coverage under a general storm water permit if:

• • it is consistent with the approved TMDL or TMDL implementation plan; and
• • the discharger incorporates the limitations, conditions, and requirements applicable to its discharge, including monitoring frequency and reporting required by TCEQ rules, into its SWP3 or storm water management plan unless these limitations, conditions, and requirements are already reflected directly in the general permit itself.

Even if a TMDL has not yet been developed and implemented for the constituent or constituents of concern, discharges to impaired water bodies must not cause or contribute to the impairment (See 30 TAC Chapter 305 Consolidated Permits).

Discharges to the Edwards Aquifer Recharge Zone Discharges of storm water associated with industrial activity, and other non-storm water discharges, cannot be authorized where those discharges are prohibited by 30 TAC Chapter 213 (Edwards Aquifer). New discharges located within the Edwards Aquifer Recharge Zone, or within that area upstream from the recharge zone and defined as the Contributing Zone, must meet all applicable requirements of, and operate according to, 30 TAC Chapter 213.

Discharges to Specific Watersheds and Water Quality Areas Discharges of storm water associated with industrial activity, and other non-storm water discharges, cannot be authorized where prohibited by provisions of 30 TAC Chapter 311 (Watershed Protection) for water quality areas and watersheds.

Site-Specific Standards and Variances

General Provisions As stated in § 307.2(d)(3) of the Standards, the narrative provisions, the designated uses, the presumed uses, and the numerical criteria of the Standards may be amended to account for local conditions. Adoption of a site-specific standard is an explicit amendment to the Standards that requires EPA approval and an opportunity for public hearing.

In cases where site complications require substantial additional time to justify, review, and approve a site-specific standard, a temporary variance (variance) for an existing facility may be requested before or during the permit application process to allow the permittee time to gather information to support a site-specific standard. A variance is not equivalent to a site-specific standard, which is a rule change. Variance procedures are defined in § 307.2(d)(5) of the Standards. Preliminary evidence indicating that a site-specific standard may be appropriate should be submitted to the TCEQ to show that a variance is warranted.

The information necessary to justify a variance is only a part of the process of justifying a site-specific standard. The applicant should continue to develop more comprehensive information to support the site- specific standard. Technical guidance to support a site-specific standard is given in the following sections of this document: “Site-Specific Standards for Aquatic Life Use” (see page 195), “Site-Specific Standards for Recreational Use” (see page 199), “Site-Specific Numerical Standards for Aquatic Life” (see page 202), and “Site-Specific Standards for Total Toxicity” (see page 207).

Interim Permit with a Variance A variance may be requested before or during the permit application process. The TCEQ includes all variance requests in the Notice of Application and Preliminary Decision, and the public is given the opportunity to request a hearing on both the variance and the TPDES permit. A variance for a TPDES permit also requires EPA approval. The TCEQ’s approval of a variance along with the TPDES permit formally recognizes that a site-specific standard may be justified based on preliminary evidence provided by the applicant. The variance is approved by the TCEQ as conditions in the permit that provide interim effluent

limits or monitoring requirements. Permit conditions for the pollutant or pollutants of concern are normally the same as in the previous permit. However, the application of a variance cannot impair an existing, attainable, or designated use. As stated in § 307.2(d)(5)(D) of the Standards, the permit must preclude degradation. A TPDES permit that contains an approved variance is issued for up to a three-year term.

The variance consists of special provisions in the TPDES permits, which establish a schedule for the permittee to submit a work plan to study the stream characteristics, aquatic life uses, or other site-specific information about the receiving water. Upon approval of the work plan, the permittee performs the study in accordance with the approved work plan. Final effluent limits based upon the existing standard are not applied in the permit, since the appropriateness of the existing standard is in question and under study. However, the permit will specify the effluent limits that would be applied in the next permit if the permittee does not comply with the requirements of the variance or if the existing standard is not revised.

The variance provisions in the short-term permit allow the permittee time to gather information necessary to fully support a site-specific standard. With this information, the applicant should request the site-specific standard in writing and submit the approved study to the TCEQ at least 180 days before the expiration date of the permit.

A permittee may also request a variance where an existing permit already includes a compliance period to meet the Standards. In this case, the existing permit (which includes a compliance period for the pollutant of concern) is amended to recognize the variance request. If granted, the variance will expire no later than three years following the issue date for the permit that previously specified a compliance period.

Variance Extensions When the TCEQ receives the permit renewal application and the study of stream characteristics, aquatic life uses, or other site-specific information about the receiving water, a technical review of this information is conducted. A recommendation on the effluent limits for the succeeding permit is made, based upon the permittee’s fulfillment of the variance requirements and whether the TCEQ agrees the site-specific standard is warranted.

Recommend that the Standard be Revised In this situation, the TCEQ determines that the proposed site-specific standard is appropriate, and EPA determines that it is technically approvable. If the revision to the Standards can be processed and completed before the TPDES permit is renewed, then the permit is issued

with final effluent limits based upon the revised standard. Otherwise, the succeeding permit is renewed with a variance extension. The interim effluent limits will be extended from the previous permit to allow additional time for a site-specific standard to be adopted into the Standards and approved by EPA.

Once the site-specific standard is adopted and approved by EPA, the permittee can seek to have the TPDES permit amended to include or remove effluent limits to reflect the new standard. If this new standard requires an upgrade in treatment, the permit may include a compliance schedule to achieve the effluent limits needed to meet the final standard. As described in § 307.2(f) of the Standards, up to three years from the effective date of the permit’s issuance is provided to allow sufficient time for the permittee to modify the effluent quality.

Recommend that the Standard not be Revised In this situation, the TCEQ (or the EPA) does not believe the study supports the site-specific standard. The succeeding permit may include a compliance schedule to achieve the effluent limits needed to meet the existing standard. As described in § 307.2(f) of the Standards, up to three years from the effective date of the permit’s issuance is provided to allow sufficient time for the permittee to modify the effluent quality.

When the permittee has not complied with the conditions in the variance, then the succeeding permit is issued with final effluent limits based upon the existing standard, effective immediately. The TCEQ does not grant a compliance period with interim effluent limits in this situation, since the permittee did not perform the required study or otherwise fulfill the requirements of the variance.

Coordinating with EPA In the memorandum of agreement (MOA) with EPA delegating the NPDES program to the state, the TCEQ agreed that EPA would review all draft TPDES permits that include a recommendation of a variance. The TCEQ routes draft permits with a variance or variance extension to EPA, along with the technical information that the permittee provides to support the variance request. EPA reviews the variance request within 45 days and may confer with the USFWS on endangered species issues during this review period. By the end of the 45-day review, EPA either (1) approves the variance and draft permit or (2) specifies any interim objections. Any interim objections have to be resolved before the TCEQ can proceed.

Further details of procedures for federal review of TPDES permits can be found in the TPDES MOA, which is available on the agency’s Web site (see footnote 2 on page 21).

Temporary Standards Where a criterion is not attained and cannot be reasonably attained for one or more of the reasons listed in 40 CFR Part 131.10(g), then a temporary standard for a specific water body may be adopted as part of § 307.10 of the Standards as an alternative to downgrading uses. Reasons for a temporary standard are as follows:

• • Naturally occurring pollutant concentrations prevent the attainment of a use;
• • Natural, ephemeral, intermittent, or low-flow conditions or water levels prevent the attainment of the use;
• • Human-caused conditions or sources of pollution prevent the attainment of the use and cannot be remedied or would cause more environmental damage to correct than to leave in place;
• • Dams, diversions, or other types of hydrological modifications preclude the attainment of the use, and it is not feasible to restore the water body to its original condition or operate such modification in a way that would result in the attainment of a use;
• • Physical conditions related to the natural features of the water body, such as the lack of a proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality, preclude attainment of aquatic life protection uses; or
• • Controls more stringent than those required by §§ 301(b) and 306 of the federal Clean Water Act would result in substantial and widespread economic and social impact.

In accordance with § 307.2(g) of the Standards, the following provisions apply to temporary standards:

• • A criterion that is established as a temporary standard must be adopted as stated in the provisions of § 307.2(d)(3) of the Standards.
• • A temporary standard must identify the water body or water bodies where the criterion applies.

• • A temporary standard will identify the numerical criteria that will apply during the existence of the temporary standard, and a remediation plan to address compliance with designated uses and criteria will be provided for approval by the EPA.
• • A temporary standard does not exempt any discharge from compliance with applicable technology-based effluent limits.
• • A temporary standard must expire no later than the completion of the next triennial revision of the Standards.
• • When a temporary standard expires, subsequent discharge permits will be issued to meet the applicable existing water quality standards.
• • If sufficiently justified as stated in the provisions of § 307.2(d)(3) of the Standards, a temporary standard can be renewed during revision of the Standards.
• • A temporary standard cannot be established that would impair an existing use.

Permits including a limit based on a temporary standard typically: (1) are issued for three years, (2) are amended by staff after three years, or (3) include another option that precludes allowing limits to be based on the temporary standard for an extended (five-year) period if the temporary standard is removed from the Standards.

Site-Specific Standards for Aquatic Life Use For unclassified water bodies, aquatic life uses are assessed as described in the chapter of this document entitled “Determining Water Quality Uses and Criteria” on page 14. In cases where the preliminary assessment indicates that the attainable aquatic life use for a particular unclassified water body might be lower than the presumed aquatic life use, an aquatic life use-attainability analysis (UAA) is conducted as discussed in this section. UAAs are also conducted on classified streams where the attainable aquatic life use has become lower than the designated use.

The rest of this section explains:

• • the procedures used to review and approve UAAs;
• • how to conduct UAAs for typical sites on unclassified streams; and
• • the kinds of site complications that require additional analysis.

Aquatic Life UAA Review and Approval TCEQ staff review each UAA in order to ensure conformance with the basic protocol. If the UAA indicates that the attainable use is lower than the designated use for a classified stream or if the TCEQ decides a lower aquatic life use designation is justified for an unclassified stream, then the TCEQ sends the UAA to EPA Region 6 for review and preliminary approval. The TCEQ sends the results of the UAA to the EPA as a summary report with the presentation of results in the appropriate format as described in Appendix C of TCEQ’s Surface Water Quality Monitoring Procedures, Volume 2: Methods for Collecting and Analyzing Biological Assemblage and Habitat Data, RG-416. After reviewing the UAA, the EPA sends a response to the TCEQ.

Aquatic Life UAAs for Unclassified Streams Within 30 days after receiving a UAA for a “typical site” on an unclassified stream, the EPA reviews the UAA in accordance with the protocol entitled “UAA for Typical Sites” on page 197 and provides a response to the TCEQ. Additional time may be needed for EPA review of streams with “site complications” (see page 199 for more information). Preliminary approval of a UAA for an unclassified stream by the EPA constitutes a finding that the requested aquatic life uses and criteria for the stream are “approvable” for a site-specific designation in the Standards.

The TCEQ will designate site-specific aquatic life uses in Appendix D of the Standards. To the extent possible, the public notification and public hearing requirements for adopting a site-specific standard may be conducted in conjunction with the public participation procedures for any permit actions that affect the particular site.

After the TCEQ and EPA final approval of the revised Standards, TPDES discharge permits are issued with effluent limits based upon the new site- specific standard designation. The new site-specific standard is also included in the TCEQ’s Water Quality Management Plan (WQMP).

Aquatic Life UAAs for Classified Streams For classified streams, the EPA may need more than 30 days to review the UAA. Lowering a designated aquatic life use on a classified water body takes a more extensive study than for lowering the presumed aquatic life use of an unclassified stream. A UAA for a classified stream requires that representative sites throughout the segment be evaluated rather than one typical site as for an unclassified stream.

Preliminary approval of a UAA by the EPA for classified streams constitutes a finding that the lowered aquatic life use is “approvable” as the new designated use for the classified stream. The change in the designated use is placed in the next revision of the Standards.

Aquatic Life UAAs for Typical Sites Data collection, compilation, and analysis may be conducted by the TCEQ, an applicant, river authorities, or governmental or other entities. Any person or entity planning to conduct a UAA should coordinate with the TCEQ. In addition, regional staff of the Texas Parks and Wildlife Department and the TCEQ, the Texas State Soil and Water Conservation Board, and local stakeholders in the watershed should be notified about the proposed UAA project.

Classified Streams Procedures to conduct a UAA on a classified stream are described in the most recent version of the TCEQ’s Surface Water Quality Monitoring Procedures, Volume 2: Methods for Collecting and Analyzing Biological Assemblage and Habitat Data, RG-416. In addition, procedures for conducting instantaneous field measurements, 24-hour dissolved oxygen monitoring, and conventional water chemistry sampling for a UAA are contained in the most recent version of the TCEQ’s Surface Water Quality Monitoring Procedures, Volume 1: Physical and Chemical Monitoring Methods for Water, Sediment, and Tissue, RG-415. Results of a UAA for a classified stream should be submitted in the appropriate format (described in Appendix C of RG-416) to the TCEQ for review.

Unclassified Streams―Applicability The aquatic life UAA procedures in this section may be used under the following conditions:

• • A sample site unimpacted by a pollutant source is available (or data already exists for a reference area), such as in the projected area of impact for a new permit, or upstream of an existing permit.
• • The attainable use is not impaired by other sources of pollution at critical conditions.
• • The characteristic aquatic life use in unimpacted reference areas is lower than the statewide or region-wide presumed use. This corresponds to one or more of the following reasons for lowering a designated use listed in 40 CFR Part 131:

◦ Naturally occurring poor water quality prevents the attainment of the use.

◦ Natural stream flow conditions prevent the attainment of the use.

◦ Physical characteristics of the stream channel (morphometry) preclude attainment of aquatic life uses.

◦ Hydrologic modifications (dams, spillways, intake structures, etc.) preclude the attainment of the use, and the impacts cannot be reasonably mitigated.

Unclassified Streams―Summary of Aquatic Life UAA Procedures The following items summarize the aquatic life UAA procedures for typical sites:

• • Conduct the UAA in accordance with the appropriate biological fact sheet in the most recent version of the TCEQ’s Surface Water Quality Monitoring Procedures, Volume 2: Methods for Collecting and Analyzing Biological Assemblage and Habitat Data, RG-416.
• • Identify reference areas and define stream reach or reaches to be included in the assessment.
• • Summarize stream morphometry, flow characteristics, and habitat characteristics in the reference area in accordance with:

◦ a standardized stream characteristics form (from a TCEQ wastewater permit application), which also contains a description of the proposed or existing discharge; or

◦ the most recent version of the TCEQ’s Surface Water Quality Monitoring Procedures, Volumes 1 and 2, RG-415 and RG-416. This document is available on the agency’s Web site (www.tceq.state.tx.us); follow the link for “Publications.”

• • Conduct fish sampling (or in some cases macroinvertebrate sampling) in the reference area in accordance with the RG-416 (see preceding bulleted item).
• • Apply quantitative indices in accordance with the RG-416, cited above.
• • Conduct instantaneous field measurements, 24-hour dissolved oxygen monitoring, and conventional water chemistry sampling in accordance with RG-415 and the appropriate biological fact sheet in RG-416.

• • Submit the results of the UAA in the appropriate format, as described in Appendix C of RG-416, to the TCEQ’s Water Quality Standards Group in the Water Quality Planning Division for review.

Site Complications Requiring Additional Justification In unusual situations, there may be site-specific complications that indicate more information is needed to justify an aquatic life use that is less than the presumed use for an unclassified water body. Examples of such situations and the types of additional information that may be appropriate are listed below.

Examples of Site-Specific Complications • The reasonably attainable uses in the receiving waters are impacted by an existing discharge and are considered to be lower than the naturally occurring uses in an appropriate reference area (for example, upstream).

• • No suitable reference areas are available for sampling.
• • Dissolved oxygen criteria for a particular aquatic life use are inappropriate for the site.

Examples of Additional Analyses • Water quality modeling simulations to evaluate treatment options.

• • Additional investigation of pollutant sources and instream impacts.
• • Sampling and evaluation of additional parameters, such as diel measurements of dissolved oxygen.
• • Technical and economic feasibility of attaining the presumed use.

Site-Specific Standards for Recreational Use Categories of recreational uses and applicable criteria are established in §§ 307.4(j) and 307.7(b)(1) of the Standards. In cases where site- specific information indicates that the attainable recreational use for a particular unclassified water body might be lower than the presumed recreational use, a Basic Recreational UAA Survey or Comprehensive Recreational UAA can be conducted as discussed in this section. Comprehensive Recreational UAAs can also be conducted on classified water bodies where there is an indication that the attainable recreational use is lower than the designated use.

The remainder of this section explains:

• • the procedures used to review and approve recreational UAAs. • how to conduct Basic Recreational UAA Surveys and Comprehensive Recreational UAAs.

Recreational UAA Review and Approval The TCEQ reviews each UAA in order to ensure conformance with the TCEQ recreational UAA procedures and to determine if a lower recreational use is justified. If the UAA indicates that the recreational use is less stringent than the designated or presumed use, the TCEQ submits the UAA to EPA Region 6 for review and preliminary approval. The TCEQ sends the results of the UAA to the EPA as a summary report with a copy of the recreational UAA report attached. After reviewing the UAA, the EPA sends a response to the TCEQ.

Recreational UAAs for Unclassified Water Bodies Within 30 days after receiving a UAA for an unclassified water body, the EPA reviews the UAA in accordance with the TCEQ recreational UAA procedures and provides a response to the TCEQ. Additional time may be needed for EPA review of complex recreational UAAs. Preliminary approval of a recreational UAA by the EPA constitutes a finding that the requested recreational uses and criteria for a water body are “approvable” for a site-specific designation in the Standards. The change in the presumed use will be proposed for adoption in the next revision of the Standards.

Recreational UAAs for Classified Water Bodies For classified water bodies, the EPA may need more than 30 days to review the UAA. Lowering a designated recreational use on a classified water body takes a more extensive study than for lowering the recreational use of an unclassified water body. Preliminary approval of a UAA by the EPA for classified water bodies constitutes a finding that the lowered recreational use is “approvable” as the new designated use for the classified water body. The change in the designated use is placed in the next revision of the Standards.

How to Conduct Recreational UAAs

Applicability Data collection, compilation, and analysis may be conducted by the TCEQ, river authorities, or governmental or other entities. The recreational UAA procedures summarized in this section may be used under the following conditions:

• • The attainable use is not impaired by sources of pollution.
• • The attainable recreational use is lower than the presumed or designated use. This corresponds to one or more of the following reasons for lowering a designated use listed in 40 CFR Part 131:

◦ Naturally occurring poor water quality prevents the attainment of the use. Sources of pollution cannot be reasonably controlled by existing regulations.

◦ Natural, ephemeral, intermittent, or low stream flow conditions prevent the attainment of the use.

◦ Physical characteristics of the stream channel (morphometry) preclude attainment of aquatic life uses.

◦ Hydrologic modifications (dams, spillways, intake structures, etc.) preclude the attainment of the use, and the impacts cannot be reasonably mitigated.

Summary of Recreational UAA Procedures Basic Recreational UAA Surveys and Comprehensive Recreational UAAs should be conducted in accordance with the TCEQ’s Recreational UAA procedures. These procedures are available upon request from the TCEQ’s Water Quality Standards Group in the Water Quality Planning Division. The following items summarize the UAA procedures for typical sites:

• • Coordinate with local entities and the TCEQ.
• • Identify the water body and select sites.
• • Conduct the UAA during a normal dry/warm season (March-October) when water body recreation is most likely to occur.
• • Summarize the following information in accordance with the TCEQ’s Recreational Use Attainability Analysis Procedures:

◦ water body and flow characteristics ◦ watershed characteristics ◦ stream channel and substantial pool measurements ◦ weather conditions ◦ historical information ◦ observed uses ◦ indications of human use ◦ water quality data (air and water temperature)

Persons performing a recreational UAA are to complete the associated contact information form, field data sheets, Comprehensive Recreational UAA interview form, and Recreational UAA summary sheet included in the procedures.

• • Submit Basic Recreational UAA Surveys or Comprehensive Recreational UAA reports as described in the recreational UAA procedures to the TCEQ for review.

Wildlife Sources of Bacteria In situations where the weight of evidence obtained from sanitary surveys, bacteria source tracking, UAAs, or similar studies demonstrate that sources of bacteria are unavoidably high (e.g. in wildlife preserves with very large waterfowl populations and limited aquatic recreational potential), site-specific uses, such as secondary contact recreation, may be designated for individual water bodies in the Standards.

Site-Specific Numerical Standards for Aquatic Life A permittee may pursue a standards modification where local site-specific factors suggest that the numerical criteria are inappropriate for a particular water body. These factors are defined in § 307.6(c)(10) of the Standards.

The following paragraphs discuss these factors in more detail. Information that may establish the presence of these factors should be submitted as part of a permit application. Based on the existence of these factors, a permittee may seek a permit amendment to modify final effluent limits. An application to amend a permit does not delay the effective date of final effluent limits as established in an existing permit; therefore, an amendment application should be submitted well in advance of the effective date of the final effluent limits to allow full TCEQ consideration and final decision. The remainder of this section discusses each factor and how TCEQ staff evaluates information submitted by a permit applicant.

Where an applicant believes that a metal standard is inappropriate, the applicant should carefully evaluate recent effluent analytical data to ensure that effluent metals concentrations do in fact exceed levels necessary to comply with existing standards. The applicant should employ clean techniques for all sample-handling and analytical procedures to avoid sample contamination.

Background Concentrations of Specific Toxics Through sampling of the receiving water in an area unimpacted by dischargers, the applicant should demonstrate that toxic pollutants exist naturally at concentrations higher than the instream criteria. See § 307.6(c)(10)(A) of the Standards. Where the background concentration is greater than the instream criteria, the TCEQ establishes effluent limits that will preclude further increase in the background concentration.

Persistence and Degradation Rate of Specific Toxics The applicant may demonstrate that a specific toxic pollutant in the effluent has a short half-life within the defined mixing zone of the receiving water due to chemical reactions with naturally occurring compounds, degradation in ultraviolet light, and so forth. See § 307.6(c)(10)(B) of the Standards. This demonstration should be made using receiving water while simulating natural conditions as much as possible. The applicant may also use instream studies of existing discharges.

The applicant should provide proof of degradation and determine that receiving water concentrations of the toxic pollutants of concern do not exceed appropriate criteria. In addition, the applicant should determine the worst-case scenario or demonstrate that the degradation rate is independent of seasonal fluctuations in water chemistry (for example, temperature, pH, dissolved oxygen, and hardness).

Interactions of Toxic Substances with Other Toxic or Nontoxic Materials A synergistic interaction is a situation in which the combined effect of two or more chemicals is greater than the sum of the effect of each substance alone. See § 307.6(c)(10)(C) of the Standards. An additive interaction is a situation in which the toxicity of a mixture of chemicals is approximately the same as that expected from a simple summation of the known toxicity of each of the individual chemicals in the mixture. An antagonistic interaction is a situation in which a mixture of toxicants exhibits a less- than-additive toxic effect.

The applicant may demonstrate that toxicity in an effluent is caused by a synergistic, antagonistic, or related interaction. By modifying the concentration of a certain chemical in the effluent, the applicant may be able to show that a reduction of effluent toxicity will result without the removal of other suspected toxicants. This demonstration should be made by performing whole effluent toxicity (WET) tests on effluent or in-situ, either from a working wastewater treatment system or a pilot project, using receiving waters. However, a synergistic interaction may necessitate stricter permit limits to protect the receiving waters.

Measurements of Total Effluent Toxicity To demonstrate that a site-specific standard may be appropriate, an applicant may perform WET tests using indigenous receiving water species. See § 307.6(c)(10)(D) of the Standards. The WET tests should be conducted before submitting the permit application. The applicant should conduct an assessment of the receiving water to determine the species present. A diverse, representative, and sensitive group of species should be tested for short- and long-term impacts. The permittee should also demonstrate that sensitive, indigenous species will not be adversely affected, and aquatic life and other uses will not be impaired.

Effluent limits based on specific numerical criteria may not be raised if bioaccumulation or persistence in the food chain or the environment may produce long-term impacts that cannot be measured by WET tests. All alternate site-specific conditions related to chronic or 48-hour acute WET testing are subject to EPA review and approval.

Indigenous Aquatic Organisms An applicant may demonstrate that indigenous aquatic organisms are not affected by the effluent at the same concentration as species used to develop the criteria in the standards. See § 307.6(c)(10)(E) of the Standards. This demonstration may be accomplished by performing a detailed survey of aquatic organisms in the water body in areas in and out of the effluent plume. The applicant should also prepare a statistical analysis of the impacts to the receiving water. In addition, the applicant should evaluate the relative sensitivities of indigenous organisms to particular toxicants of concern.

The permittee may calculate a site-specific criterion if the assemblage of indigenous aquatic organisms satisfies the minimum family and genus totals defined in Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses by the U.S. Environmental Protection Agency, Office of Research and Development, NTIS Accession Number PB85-227049, (Stephan et al.), 1985.

Technological or Economic Limits of Treatability for Specific Toxic Materials If the permittee cannot achieve the required effluent limits (normally no lower than the MAL) by best available technology (BAT), then the permittee may apply for a modification of the effluent limit. See § 307.6(c)(10)(F) of the Standards. An applicant seeking an effluent limit modification due to treatment technology limitations should demonstrate, through the use of pilot tests, the level to which the specific toxic pollutant of concern can be treated using state-of-the-art treatment.

The permittee should submit an evaluation of the costs of treatment required to meet the water-quality based effluent limit and include a comparison of BAT or existing costs with estimated costs of state-of-the- art treatment. In this evaluation, the applicant should outline the incremental changes to the existing wastewater treatment facility to achieve state-of-the-art treatment. These changes might include alterations in raw materials, manufacturing processes, products produced, and energy requirements. Also, the applicant should demonstrate that improvements in best management practices or a simple raw material substitution would not achieve the treatment level required to meet effluent limits based on water quality criteria.

The applicant should show that existing or designated receiving water quality uses are not impaired due to the modified permit limits.

Bioavailability of Specific Toxic Substances The applicant may demonstrate that the chemical species of a particular substance in the effluent does not induce toxic effects or has a much less toxic effect than another species of that substance. See § 307.6(c)(10)(G) of the Standards. The applicant should prove that the species present in the effluent does not convert chemically or biologically to a more toxic form upon entering and mixing with receiving waters. If the demonstration does not induce toxic effects, the permit limit may be established based on the combined toxicity of the chemical species in the effluent.

If, however, a toxic substance in an effluent converts chemically or biologically to a more toxic species upon entering or mixing with receiving waters, then the permit limit may be established based upon the toxicity of the more toxic chemical species.

When a permit limit based on an aquatic life criterion is proposed, the applicant may wish to develop a water-effect ratio (WER) to adjust the criterion. A WER accounts for the difference in the toxicity of a metal in laboratory water from the toxicity of metals in the permittee’s receiving water. Permittees should follow the EPA’s guidance document, Interim Guidance on Determination and Use of Water-Effect Ratios for Metals,

EPA-823-B-94-001, 1994 (or most recent revision), when conducting these studies.

WERs obtained using the methods described in this EPA guidance document cannot be used to adjust aquatic life criteria that were derived for metals in other ways. Therefore, WERs using these methods cannot be used to adjust the residue-based chronic criterion for mercury, or the field- based selenium freshwater criteria.

Permit applicants may also develop WERs using the EPA’s Streamlined Water-Effect Ratio Procedure for Discharges of Copper, EPA-822-R-01- 005, March 2001. The streamlined procedure does not supersede the 1994 interim guidance; rather it provides an alternative approach for discharges of copper into a freshwater environment. Permittees in this situation may choose between using the 1994 interim guidance or the streamlined procedure. Some of the features of the streamlined procedure are as follows:

• • The procedure applies to continuous discharges of copper into freshwater.
• • A minimum of two sampling events should be performed at least one month apart.
• • The site water should be prepared by mixing effluent and upstream receiving water to achieve the critical dilution.
• • The WER for a single sampling event is calculated by dividing the site water LC50 by the greater of

◦ the lab water LC50; or

◦ the species mean acute value. The SMAV, which is usually found in EPA criteria documents, is the mean LC50 or EC50 from a group of published toxicity tests with laboratory water.

• • A minimum of two WERs should be used to calculate the final WER.
• • The final WER is the geometric mean of the two (or more) sampling event WERs.

New Information Concerning the Toxicity of a Substance An applicant or other interested party may provide new or updated information that indicates that the toxicity of a substance is significantly different from the numerical criteria in the Standards. See § 307.6(c)(10)(H) of the Standards. This information will typically consist of additional or revised toxicity exposure testing. This testing should be

conducted in accordance with Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses by the U.S. Environmental Protection Agency, Office of Research and Development (Stephan, et al.), 1985.

Site-Specific Standards for Total Toxicity Additional chemical-specific or whole effluent toxicity limits may be established in a permit as a result of confirming whole effluent toxicity at the critical dilution. These chemical-specific or whole effluent toxicity limits may be adjusted based on site-specific factors discussed in the following paragraphs. However, any discharge limit that fails to prevent significant toxicity to a test species at the designated critical dilution requires a demonstration that instream uses will not be impaired. See § 307.6(e)(2)(F) of the Standards. An effluent limit that could exceed the total toxicity requirements of the Standards requires a site-specific amendment to the rule.

The remainder of this section discusses each factor to be considered in establishing permit limits and how TCEQ staff evaluates information submitted by an applicant. All alternate site-specific conditions related to chronic or 48-hour acute WET testing are subject to EPA review and approval.

Background Toxicity of Unimpacted Receiving Waters Where background instream toxicity exists, the TCEQ may establish whole effluent or chemical-specific limits that preclude further increase in the background receiving water toxicity. See § 307.6(e)(2)(F)(i) of the Standards. The applicant should demonstrate background toxicity by assessing toxicity in an area unimpacted by the discharge.

Persistence and Degradation Rate of Principal Toxic Materials The applicant may demonstrate that chemicals responsible for toxicity in the effluent have a short half-life within the defined mixing zone of the receiving water due to chemical reactions with naturally occurring compounds, degradation in ultraviolet light, and so forth. See § 307.6(e) (2)(F)(ii) of the Standards. This demonstration should be made using receiving water while simulating natural conditions as much as possible. The applicant may also use instream studies of existing discharges. The applicant should provide proof of chemical degradation and determine that the receiving water’s total toxicity measurements do not violate appropriate criteria.

Site-Specific Variables that may Alter the Impact of Toxicity An applicant may demonstrate that existing receiving-water-specific variables alter the toxic impacts of an effluent. See § 307.6(e)(2)(F)(iii) of the Standards. The applicant should use receiving water biological studies or should perform whole effluent toxicity tests at critical conditions on receiving water samples collected immediately within the discharge plume to the end of the mixing zone.

Indigenous Aquatic Organisms An applicant may demonstrate that indigenous aquatic organisms are not affected by the effluent at the same exposure concentration as the standard WET test species defined in the permit. See § 307.6(e)(2)(F)(iv) of the Standards. This may be accomplished by performing a detailed survey of aquatic organisms in the water body in areas in and out of the effluent plume coupled with a statistical analysis of the data. In addition, the applicant should evaluate the relative sensitivities of indigenous organisms to particular toxicants of concern using literature information or WET tests.

Technological, Economic, or Legal Limits of Treatability or Control for Specific Toxic Materials If the permittee cannot achieve the required total toxicity or chemical- specific permit limits with best available technology, then the permittee may apply for a modification of the effluent limit. See § 307.6(e)(2)(F)(v) of the Standards. An applicant seeking an effluent limit modification because of the limitations of treatment technology should demonstrate, through the use of pilot tests, the level to which the specific toxic pollutant of concern can be treated using state-of-the-art treatment.

The permittee should submit an evaluation of the costs of treatment required to meet the effluent limit and include a comparison of BAT or existing costs with estimated costs of state-of-the-art treatment. In this evaluation, the applicant should outline the incremental changes to the existing wastewater treatment facility to achieve state-of-the-art treatment. These changes might include alterations in raw materials, manufacturing processes, products produced, and energy requirements.

Also, the applicant should demonstrate that improvements in best management practices, such as source control, public education, housekeeping, a simple raw material substitution, or a water treatment chemical substitution, would not achieve the treatment level required to meet effluent limits based on water quality criteria. The applicant should show that existing or designated receiving water quality uses are not impaired due to the modified permit limits.

Appendix A. Playa Lake Policy Statement

Playa Lake Policy Statement Except as otherwise provided in this policy, a permit or order of the Commission, the discharge from any existing industrial or domestic wastewater treatment facility that is authorized to use and has used a playa lake, which does not feed into any surface water of the state, as a wastewater retention facility before July 10, 1991, the effective date of TNRCC adoption of related revisions to the Texas Surface Water Quality Standards, 30 TAC Chapter 307, shall not be subject to meeting such standards or other requirements for discharges to waters in the state. However, additional requirements may be imposed in existing permits so that such discharges shall not create a nuisance or otherwise impair public health, nor cause contamination of groundwater. Such requirements include, but are not limited to, the prohibition of the discharge of raw, untreated wastewater into a playa.

Accordingly, public access to the playa lake shall be limited (e.g., by fencing and/or "no trespassing" signs) and applicable buffer zones shall be required. Additionally, because of the uncertainty of the impermeability and durability of the natural clay liner found on the bottom of a playa lake, as well as the exact location and depth of the underlying water table, groundwater quality monitoring and reporting shall be a condition of the permit or permit renewal. If groundwater contamination from the discharge is detected, a corrective action plan shall be developed and remediation measures shall be required.

If the wastewater is used for irrigation, the discharge must also meet applicable treatment levels and application rates based upon soil depth and characteristics, topography, whether the land has been plowed, crop uptake rates, and other relevant factors.

New discharges to playa lakes not previously authorized to be used as wastewater treatment or retention facilities before July 10, 1991, shall meet applicable surface water quality standards in addition to the groundwater protection requirements above. Additionally, if a finding is made that a waste discharge into a playa of industrial or municipal waste (authorized before July 10, 1991) is subject to the TPDES program, any existing permit will be amended to include a reasonable compliance period, consistent with other agency rules. Such discharges are subject to the TPDES program if the playa is considered as waters of the United States. Unclassified playa shall be presumed to have the same standards as that for an unclassified intermittent water body until more specific standards are established for this water in the state.

Appendix B. Locations of Federally Endangered and Threatened Aquatic and Aquatic-Dependent Species in Texas

Table B. Locations of Federally Endangered and Threatened Aquatic and Aquatic-Dependent Species in Texas Segment Common Name County Water Body No. 0101 Arkansas River shiner Hemphill Canadian River Below Lake Meredith Hutchinson Roberts 0103 Arkansas River shiner Oldham Canadian River Above Lake Meredith Potter 1202 Houston toad Austin Deep Creek

1209 Houston toad Leon Running Creek

1211 Houston toad Burleson Second Davidson Creek 1212 Houston toad Bastrop Marshy Branch

Lee Blue Branch Milam Hills Branch 1242 Houston toad Burleson Sweet Gum Branch 1302 Houston toad Colorado Hayes Creek

1402 Houston toad Colorado Redgate Creek 1409 Concho water snake Lampasas Colorado River Above Lake Buchanan San Saba 1410 Concho water snake Brown Colorado River Below O. H. Ivie Reservoir Coleman McCulloch Mills San Saba 1411 Concho water snake Coke E. V. Spence Reservoir 1412 Concho water snake Coke Colorado River Below Lake J. B. Thomas Mitchell 1416 Clear Creek gambusia Menard Clear Creek Wilkinson Spring (headspring of Clear Creek) 1421 Concho water snake Concho Concho River Dry Hollow Kickapoo Creek Tom Green Concho River

1426 Concho water snake Coke Colorado River Below E. V. Spence Reservoir

Runnels Colorado River Below E. V. Spence Reservoir Ballinger Municipal Lake Bluff Creek Coyote Creek Elm Creek 1427 Barton Springs salamander 1 Blanco Onion Creek Hays Bear Creek Little Bear Creek Onion Creek

Segment Common Name County Water Body No. Travis Bear Creek Onion Creek Slaughter Creek Williamson Creek 1430 Barton Springs salamander 1 Hays Barton Creek

Travis Barton Creek Upper Barton Spring above Barton Springs Municipal Pool Barton Springs outflows in Travis County Eliza Springs Parthenia (= Main) Springs Sunken Garden Springs 1433 Concho water snake Coleman O. H. Ivie Reservoir Concho Runnels 1434 Houston Toad Bastrop Alum Creek Copperas Creek Gills Branch Piney Creek Price Creek Puss Hollow 1605 Houston toad Lavaca Laughlins Sandy Creek

1809 Comal Springs dryopid beetle1 Hays Fern Bank Springs

1811 Peck’s Cave amphipod 1 Comal Comal Springs 1 1811 Comal Springs dryopid beetle Comal Comal Springs 1811 Comal Springs riffle beetle 1 Comal Comal Springs 1 1811 Fountain darter Comal Comal River Landa Lake 1812 Peck’s Cave amphipod 1 Comal Hueco Springs 1814 Comal Springs riffle beetle 1 Hays San Marcos Springs Spring Lake 1814 Fountain darter 1 Hays Upper San Marcos River Purgatory Creek San Marcos National Fish Hatchery refugium Sessom Creek Spring Lake Willow Spring Creek 1814 San Marcos gambusia 1 Hays Upper San Marcos River Spring Lake 1814 San Marcos salamander 1 Hays Upper San Marcos River San Marcos National Fish Hatchery refugium San Marcos Springs outflows San Marcos Springs Spring Lake

Segment Common Name County Water Body No. 1814 Texas blind salamander 1 Hays Upper San Marcos River Ezell’s Cave pool F. Johnson’s fissure pool Primer’s fissure pool Rattlesnake Cave pool San Marcos National Fish Hatchery refugium San Marcos Springs San Marcos Springs outflows SWTSU artesian well outlet 1814 Texas wild-rice 1 Hays Upper San Marcos River San Marcos National Fish Hatchery refugium Spring Lake 2109 Fountain darter 1 Uvalde Uvalde National Fish Hatchery refugium 2109 Comanche Springs pupfish Uvalde Uvalde National Fish Hatchery refugium 2109 Texas wild-rice 1 Uvalde Uvalde National Fish Hatchery refugium

2304 Devil’s River minnow Kinney Las Moras Creek Las Moras Spring Pinto Creek Pinto Spring Sycamore Creek Val Verde Sycamore Creek 2306 Big Bend gambusia Brewster Spring 1 (Rio Grande Village, Big Bend NP) Big Bend National Park refugium 2309 Devil’s River minnow Val Verde Devils River Dolan Creek Finegan Spring Pecan Springs Phillips Creek 2311 Pecos gambusia Jeff Davis Phantom Lake Spring and canal system

Pecos Diamond Y Draw Diamond Y Spring Leon Creek Reeves Balmorhea irrigation canals East Sandia Spring Giffin Spring and canal system San Solomon Spring (Balmorhea State Park) Toyah Creek 2311 Little Aguja pondweed Jeff Davis Little Aguja Creek

2311 Comanche Springs pupfish Jeff Davis Phantom Lake Spring and canal system

Reeves Balmorhea irrigation canals Giffin Spring and canal system San Solomon Spring (Balmorhea State Park)Toyah Creek 2311 Leon Springs pupfish Pecos Diamond Y Draw Diamond Y Spring Leon Creek

Segment Common Name County Water Body No. 2311 Pecos assiminea snail Pecos Upper Pecos River Diamond Y Draw East Sandia Spring 2311 Puzzle sunflower Pecos Diamond Y Spring

2313 Devil’s River minnow Val Verde San Felipe Creek 2 2411 Piping plover Jefferson Sabine Pass

2421 Piping plover 2 Chambers Upper Galveston Bay Galveston 2422 Piping plover 2 Chambers Trinity Bay Galveston 2423 Piping plover 2 Galveston East Bay 2 2424 Piping plover Brazoria West Bay Galveston 2432 Piping plover 2 Brazoria Chocolate Bay 2 2433 Piping plover Brazoria Bastrop Bay/Oyster Lake 2 2434 Piping plover Brazoria Christmas Bay

2435 Piping plover 2 Brazoria Drum Bay 2 2439 Piping plover Galveston Lower Galveston Bay 2 2441 Piping plover Matagorda East Matagorda Bay 2 2442 Piping plover Brazoria Cedar Lakes Matagorda 2451 Piping plover 2 Calhoun Matagorda Bay/Powderhorn Lakes Matagorda 2452 Piping plover 2 Matagorda Tres Palacios Bay/Turtle Bay 2461 Piping plover 2 Calhoun Espiritu Santo Bay 2461 Whooping crane Calhoun Espiritu Santo Bay 2 2462 Piping plover Calhoun San Antonio Bay/Hynes Bay/Guadalupe Bay

2462 Whooping crane Calhoun San Antonio Bay/Hynes Bay/Guadalupe Bay 2463 Piping plover 2 Aransas Mesquite Bay/Carlos Bay/Ayres Bay

2463 Whooping crane Aransas Mesquite Bay/Carlos Bay/Ayres Bay 2 2471 Piping plover Aransas Aransas Bay

2471 Whooping crane Aransas Aransas Bay 2 2472 Piping plover Aransas Copano Bay/Port Bay/Mission Bay Refugio 2472 Whooping crane Aransas Copano Bay/Port Bay/Mission Bay Refugio 2473 Whooping crane Aransas St. Charles Bay 2 2481 Piping plover Nueces Corpus Christi Bay

Segment Common Name County Water Body No. 2483 Piping plover 2 Nueces Redfish Bay

2485 Piping plover 2 Nueces Oso Bay

2491 Piping plover 2 Cameron Laguna Madre Kenedy Kleberg Nueces Willacy 2492 Piping plover 2 Kenedy Baffin Bay/Alazan Bay/Cayo del Grullo/Laguna Kleberg Salada 2493 Piping plover 2 Cameron South Bay 2 2494 Piping plover Cameron Brownsville Ship Channel 2 2501 Piping plover Cameron Gulf of Mexico

1 Includes segments that cross the contributing and recharge zones of the southern section of the Edwards Aquifer (see Table 3 on page 23) as well as the Comal River (Segment 1811) and Lower San Marcos River (Segment 1808). 2 Discharges from petroleum facilities are evaluated to determine if there is an affect on Piping Plovers. No other types of facilities are reviewed for potential affects to Piping Plovers.

Appendix C. Critical Low-Flows and Harmonic Mean Flows for Classified Segments

Table C. Critical Low-Flows and Harmonic Mean Flows for Classified Segments

Notes on table: 1) This table contains seven-day, two-year low-flow (7Q2) values, alternative critical low-flow values for streams/rivers that are dominated by springflow (footnoted in the crit. low-flow column), and harmonic mean flow values for USGS and IBWC gages.

2) Flows are listed in TCEQ stream segment order. If there is more than one gage within a stream segment, the flows are listed from downstream to upstream order. The listed county names provide the general location of the gaging stations. Specific gage locations can be found in USGS publications.

3) If there is a gap in the data record, multiple periods of record are indicated.

4) The flow values presented here are intended as guidelines and may be recalculated as additional data become available. Critical low-flows and harmonic mean flows used in conjunction with TCEQ regulatory actions (such as discharge permits) may be adjusted based on the relative location of a discharge to a gage. Flows may also be derived from data obtained at other USGS or IBWC gaging stations not presented in the table, TCEQ monitoring stations, drainage basin comparisons, interpolations, or best available information.

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 0101 Canadian River 07228000 Hemphill 1980 2007 5.8 2.0 0103 Canadian River 07227500 Potter 1978 2007 0.23 1.3 0104 Wolf Creek 07235000 Lipscomb 1979 2007 0.38 1.1 0201 Red River 07337000 Bowie 1979 2007 1714 5017 1974 1998 07336820 Bowie 1108 4431 2005 2008 0202 Red River 07335500 Lamar 1980 2008 817 2895 1973 1989 07331600 Grayson 143 479 1997 2008 07316000 Cooke 1980 2008 268 672 0204 Red River 07315500 Montague 1979 2007 160 497 0205 Red River 07308500 Wichita 1979 2007 61 46 0206 Red River 07299570 Hardeman 1960 1982 0.11 0.57 Prairie Dog Town Fork 07299540 Childress 1979 2007 0.75 2.2 0207 Red River 07298500 Hall 2003 2007 0.10 * 0.21 * 0211 Little Wichita River 07314900 Clay 1979 2007 0.10 0.19 07312700 Clay 1979 2007 43 110 0214 Wichita River 07312500 Wichita 1979 2007 18 53 07312130 Wichita 1996 2002 2.4 5.1 0216 Wichita River 07312100 Baylor 1979 2007 0.44 1.4 1962 1979 0218 Wichita River 07311900 Baylor 1.6 6.2 1997 2007 07311700 Knox 1979 2007 6.4 14 0218 North Fork Wichita River 1961 1982 07311600 Cottle 4.3*** 8.8 1995 2007 0220 Pease River 07307800 Cottle 1979 2007 1.0 3.3

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 0222 Salt Fork Red River 07300000 Collingsworth 1979 2007 2.3 9.6 1970 1991 0224 North Fork Red River 07301300 Wheeler 0.10* 0.17 2001 2007 07311800 Knox 1979 2007 0.10* 0.86 * 0226 South Fork Wichita River 07311783 King 1986 2005 0.10 0.10* 1985 1986 07311782 King 0.10* 2.5 1987 2005 Prairie Dog Town Fork 0229 07297910 Armstrong 1979 2007 0.10* 0.61 Red River 1970 1982 0230 Pease River 07308200 Wilbarger 0.10* 0.67 1992 2007 1980 1980 0301 Sulphur River 07344200a Bowie 57 82 1982 2008 Sulphur River 07343200 Franklin 1993 2007 7.3 1.8 0303 South Sulphur River 07342500 Delta 1993 2007 1.8 2.6 0305 North Sulphur River 07343000 Delta 1979 2007 0.00 0.45 * 0306 South Sulphur River 07342465 Hunt 1992 2007 0.10 0.17 0402 Big Cypress Creek 07346000 Marion 1980 2007 18 23 1968 1989 0404 Big Cypress Creek 07344493b Camp 3.7 12 2005 2007 Little Cypress Bayou 07346070 Marion 1979 2007 0.53 0.95 0409 (Creek) 07346050 Upshur 1971 1999 0.10 * 1.1 Black Cypress Bayou 0410 07346045 Marion 1979 2007 0.10* 0.57 (Creek) 0502 Sabine River 08030500 Newton 1980 2008 1138 3298 08028500 Newton 1980 2008 788 2323 0503 Sabine River 08026000 Newton 1980 2008 352 1226 08025360 Newton 1980 2008 181 537 08022040 Panola 1979 2007 79 262 0505 Sabine River 08020900 Gregg 1996 2007 89 207 08020000 Gregg 1979 2007 59 190 08019200 Wood 1998 2007 55 128 0506 Sabine River 08018500 Wood 1979 2007 6.2 8.3 08017410 Van Zandt 1979 2007 0.30 0.89 0513 Big Cow Creek 08029500 Newton 1980 2008 34 65 0514 Big Sandy Creek 08019500 Upshur 1979 2007 12 31 0515 Lake Fork Creek 08019000 Wood 1986 2007 11 32 08041000 Jasper 1979 2007 2084 3387 0602 Neches River c 08040600 Jasper 1979 2007 1854 2822 08033500 Tyler 1979 2007 123 415 0604 Neches River 08032000 Anderson 1979 2007 82 179 0607 Pine Island Bayou 08041700 Hardin 1979 2007 3.7 18 0608 Village Creek 08041500 Hardin 1979 2007 79 253

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 0611 Angelina River 08036500 Cherokee 1979 2007 41 104 0612 Attoyac Bayou 08038000 Nacogdoches 1960 1985 26 67 08066500 Liberty 1979 2007 775 2416 0802 Trinity River 08066250 Polk 1979 2007 728 2133 08065350 Leon 1981 2008 825 2152 0804 Trinity River 08065000 Anderson 1982 2008 748 1812 08062700 Henderson 1982 2007 722 1554 08062500 Kaufman 1982 2007 678 1440

0805 Trinity River 1975 1998 08057410 Dallas 503 953 2003 2007 08057000 Dallas 1989 2007 396 768 08048543 Tarrant 1979 2007 13 38 0806 West Fork Trinity River 08048000 Tarrant 1979 2007 12 24 0810 West Fork Trinity River 08044500 Wise 1979 2007 7.0 3.9 * 0812 West Fork Trinity River 08042800 Jack 1979 2007 0.10 0.14 * 0814 Chambers Creek 08064100 Navarro 1984 2007 0.10 0.71 08062000 Kaufman 1993 2007 64 138 0819 East Fork Trinity River 08061750 Kaufman 2003 2007 25 55 08055500 Dallas 1979 2007 15 15 0822 Elm Fork Trinity River 08053000 Denton 1979 2007 61 98 * 0824 Elm Fork Trinity River 08050400 Cooke 1998 2007 0.10 0.23 1966 1990 0825 Denton Creek 08055000 Denton 11 21 2004 2007 08047500 Tarrant 1979 2007 4.4 5.6 0829 Clear Fork Trinity River 08047000 Tarrant 1979 2007 1.6 2.7 1980 1985 1991 1992 0831 Clear Fork Trinity River 08045850 Parker 1993 1996 0.20 0.90 1998 1999 2001 2005 0835 Richland Creek 08064550d Freestone 1994 2008 5.0 6.5 0837 Richland Creek 08063100 Navarro 1979 2007 0.10* 0.25 0839 Elm Fork Trinity River 08051100e Denton 1988 2008 2.0 5.9 0841 West Fork Trinity River 08049500 Dallas 1979 2007 140 270 1972 1991 0902 Cedar Bayou 08067500 Harris 0.27 1.1 2002 2007 East Fork San Jacinto 08070200 Montgomery 1984 2007 23 57 1003 River 08070000 Liberty 1979 2007 18 47 08068090 Montgomery 1984 2007 26 77 West Fork San Jacinto 08068000 Montgomery 1979 2007 21 58 1004 River 1975 1989 08067650 Montgomery 0.10* 1.5 1998 2000 1008 Spring Creek 08068500f Montgomery 1979 2007 18 48

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 08068275 Montgomery 2000 2007 1.1 0.93 08069000 Harris 1996 2007 27 57 08068800 Harris 2002 2008 5.4 16 1009 Cypress Creek 08068740 Harris 1979 2007 0.33 0.85 1979 1983 08068720 Harris 0.10* 0.31 1984 2007 1010 Caney Creek 08070500 Montgomery 1979 2007 14 30 1960 1977 1011 Peach Creek 08071000 Montgomery 11 21 1999 2007 08073700 Harris 1985 2007 51 124 1014 Buffalo Bayou 08073600 Harris 1979 2007 44 106 08073500 Harris 1979 2007 23 66 08076000 Harris 1979 2007 22 39 1016 Greens Bayou 1984 1992 08075900 Harris 12 21 2007 2008 08074500 Harris 1980 2007 31 53 1017 Whiteoak Bayou 08074020 Harris 2002 2007 14 26 1965 1992 1102 Clear Creek 08076997g Harris 0.53 2.2 2007 2008 1108 Chocolate Bayou 08078000 Brazoria 1979 2007 1.7 5.7 1976 1980 08116650 Fort Bend 689 1608 1984 2007 1202 Brazos River 08114000 Fort Bend 1979 2007 753 2041 08111500 Waller 1979 2007 841 1863 1204 Brazos River 08091000 Somervell 1979 2007 16 50 08090800 Parker 1979 2007 37 129 1206 Brazos River 08089000 Palo Pinto 1979 2007 32 96 h 08088610 Palo Pinto 1979 2007 25 62 08088000 Young 1979 2007 4.6 5.8 1208 Brazos River 08082500 Baylor 1979 2007 0.16 2.0 08110800 Robertson 1997 2007 12 47 1209 Navasota River 08110500 Leon 1980 2007 7.6 12 1211 Yegua Creek 08110000 Burleson 1969 1991 0.10* 0.33 08106500 Milam 1979 2007 70 226 1213 Little River 08104500 Bell 1979 2007 68 169 08106310 Milam 1981 1992 4.7 13 1214 San Gabriel River 08105700 Williamson 1981 2007 3.6 3.6 1970 1989 1215 Lampasas River 08104100 Bell 4.8 11 1999 2007 1217 Lampasas River 08103800 Lampasas 1979 2007 12 27 1219 Leon River 08102500 Bell 1980 2008 3.4 6.2 1221 Leon River 08100500 Coryell 1979 2007 4.7 3.2

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 08100000 Hamilton 1973 2001 0.10* 1.1 * 1223 Leon River 08099100 Comanche 1961 1986 0.10 0.28 08095200 Bosque 1977 2005 7.4 3.3 1226 North Bosque River 08095000 Bosque 1979 2007 2.6 1.9 08094800 Hamilton 1969 1999 0.45 1.5 1963 1985 1227 Nolan River 08092000 Hill 1993 1996 1.2 2.5 1998 1999 1229 Paluxy River 08091500 Somervell 1979 2007 1.6 1.3 08085500 Shackelford 1993 2008 1.5 2.7 * 08084000 Jones 1994 2008 0.10 0.35 1232 Clear Fork Brazos River * 08083230 Jones 2002 2008 0.10 0.10* 08083100 Fisher 1994 2008 0.10* 0.10* 1238 Salt Fork Brazos River 08082000 Stonewall 1980 2008 0.10* 0.31 Double Mountain Fork 1241 08080500 Stonewall 1980 2008 0.10* 0.62 Brazos River 08110200 Washington 1966 1983 526 1536 i 08108700 Brazos 1979 2007 489 1129 1242 Brazos River 08098290 Falls 1979 2007 167 459 08096500 McLennan 1979 2007 52 128 *** 08104310 Bell 1984 1996 16 32 1243 Salado Creek 08104290 Bell 1984 1996 2.5† 2.6 1244 Brushy Creek 08106300 Milam 1968 1980 3.4 6.2 * 1246 Middle Bosque River 08095300 McLennan 1960 1985 0.10 0.46 08104700, San Gabriel River Williamson 1981 2007 3.5 7.6 08104900j 1248 North Fork San Gabriel 08104700 Williamson 1981 2007 1.1 1.9 River South Fork San Gabriel 1250 08104900 Williamson 1979 2007 0.25 0.67 River 1253 Navasota River 08110325 Limestone 1979 2007 0.10* 0.23 * 1255 North Bosque River 08093700 Erath 1960 1979 0.10 0.10* 1257 Brazos River 08093100 Hill 1979 2007 26 84 1302 San Bernard River 08117500 Fort Bend 1979 2007 14 59 08162500 Matagorda 1980 2008 206 471 08162000 Wharton 1980 2008 419 950 1402 Colorado River 08161000 Colorado 1980 2008 378 1005 08160400 Fayette 1988 2008 341 919 1409 Colorado River 08147000 San Saba 1980 2008 34 27 * 08138000 Brown 1998 2007 0.10 1.5 1410 Colorado River 08136700 Coleman 1990 2008 3.9 7.7 * 1412 Colorado River 08123850 Coke 1993 2008 0.10 0.38

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 08121000 Mitchell 1980 2008 0.10* 0.14 * 08119500 Scurry 1960 1989 0.10 0.13 08153500 Blanco 1980 2008 4.2 6.6 1414 Pedernales River 1980 1992 08152900 Gillespie 2.9 5.3 1998 2008 08151500 Llano 1980 2008 55 85 1974 1992 Llano River 08150700 Mason 82 149 1998 2007

1415 1974 1992 08150000 Kimble 80 124 1998 2007 South Llano River 08149400 Edwards 1959 2008 13*** 22 1960 1977 North Llano River 08148500 Kimble 2.7 4.2 2002 2007 1975 1993 08146000 San Saba 21 29 1998 2008

1416 San Saba River 1980 1993 08144600 McCulloch 1.3 2.0 1998 2008 1975 1993 08144500 Menard 9.7 18 1998 2007 1417 Pecan Bayou 08143600 Mills 1979 2007 1.6 2.4 * 1420 Pecan Bayou 08140700 Brown 1968 1978 0.10 0.10* 08136500 Concho 1980 2008 0.10* 0.61 Concho River 1421 08136000 Tom Green 1980 2008 0.10 0.24 North Concho River 08135000 Tom Green 1960 1990 0.12 0.32 1975 1995 Middle Concho River 08128400 Irion 0.10* 0.55 2001 2008 1424 1930 1995 South Concho River 08128000 Tom Green 2.4*** 6.9 2001 2008 08126380 Runnels 1979 2007 0.89 1.8 1426 Colorado River 08124000 Coke 1980 2008 0.41 0.26 * 08159000 Travis 1979 2007 0.10 0.79 2003 2003 08158827 Travis 0.10* 0.24 2005 2008 1427 Onion Creek 1980 1983 08158800 Hays 0.10* 0.10* 1992 1995 08158700 Hays 1980 2008 0.19 0.61 1428 Colorado River 08158000 Travis 1980 2008 105 300 ** Barton Springs 08155500 Travis 1978 2007 11 49 * 08155400 Travis 1999 2007 0.10 0.32 * 1430 08155300 Travis 1979 2007 0.10 0.19 Barton Creek 08155240 Travis 1989 2007 0.13 0.54 1978 1982 08155200 Travis 0.10* 0.37 1989 2007 1432 Pecan Bayou 08143500 Brown 1960 1983 0.10* 0.43 1434 Colorado River 08159500 Bastrop 1998 2008 355 969

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 08159200 Bastrop 1980 2008 305 787 1502 Tres Palacios River 08162600 Matagorda 1979 2007 7.3 16 08164000 Jackson 1979 2007 16 1.4 1602 Lavaca River 08163500 Lavaca 1964 1992 0.74 1.6 08164390 Jackson 1997 2007 4.3 1.2 1605 Navidad River 08164300 Lavaca 1979 2007 1.5 1.6 1802 Guadalupe River 08188800 Calhoun 2001 2007 930 1690 08176500 Victoria 1979 2007 525 850 1803 Guadalupe River 08175800 De Witt 1979 2007 525 804 08173900 Gonzales 1997 2007 489 902 08167500 Comal 1980 2008 74 115 08167000 Kendall 1980 2008 55 100

1806 Guadalupe River 08166200 Kerr 1987 2007 47 84 1978 1985 08166140 Kerr 52 78 1999 2007 08165500 Kerr 1979 2007 30 47 08177500 Victoria 1980 2007 2.2 2.2 1807 Coleto Creek 08176900 Victoria 1980 2007 1.2 0.90 1808 San Marcos River 08172000 Caldwell 1939 2007 81*** 185 1809 Blanco River 08171300 Hays 1980 2008 6.0 3.6 1971 1993 08173000 Caldwell 2.3 7.2 1810 Plum Creek 2002 2007 08172400 Caldwell 1979 2007 0.10* 0.23 ** 08169000 Comal 1928 2008 64 226 1811 Comal River 08168710 Comal 1928 2008 13** 241 08168500 Comal 1980 2008 112 178 1812 Guadalupe River 08167800 Comal 1980 2008 96 137 *** 1813 Blanco River 08171000 Hays 1928 2008 9.4 31 ** 1814 San Marcos River 08170000 Hays 1957 2008 55 155 1974 1993 1816 Johnson Creek 08166000 Kerr 11 20 1999 2007 North Fork Guadalupe 1817 08165300 Kerr 1967 2007 13*** 24 River 1901 San Antonio River 08188500 Goliad 1979 2007 205 403 1902 Cibolo Creek 08186000 Karnes 1979 2007 15 28 08181500 Bexar 1979 2007 78 137 1973 1995 08180800 Bexar 42 78 1998 2003

1903 Medina River 1981 1995 08180700 Bexar 34 61 1997 2007 08180640 Medina 1987 2000 29 42 1960 1973 08180500 Medina 20 31 2001 2007

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 1905 Medina River 08178880 Bandera 1983 2008 8.2*** 12 1906 Leon Creek 08181480 Bexar 1985 2007 2.5 5.7 08183900 Kendall 1965 1995 1.1 1.8 1908 Cibolo Creek 08183850 Kendall 1997 2006 0.15 0.41 08178800 Bexar 1980 2008 3.9 5.4 1910 Salado Creek * 08178700 Bexar 1978 2006 0.10 0.10 08183500 Karnes 1980 2008 144 321 08181800 Bexar 1980 2008 136 299 1911 San Antonio River 08178565 Bexar 1987 2007 13 36 08178050 Bexar 1993 2007 8.7 20 1912 Medio Creek 08180750 Bexar 1987 1995 4.0 5.8 * 1913 Cibolo Creek 08185000 Bexar 1980 2008 0.10 0.10* 2002 Mission River 08189500 Refugio 1979 2007 4.7 1.2 2004 Aransas River 08189700 Bee 1979 2007 1.5 2.3 08211500 San Patricio 1990 2007 0.10* 1.1 2102 Nueces River 08211200 San Patricio 2000 2007 66 137 08211000 San Patricio 2000 2007 53 121 * 08194600 Live Oak 1965 1977 0.10 0.37 2104 Nueces River * 08194500 McMullen 1979 2007 0.10 0.29 * 08194000 La Salle 1979 2007 0.10 0.32 2105 Nueces River * 08193000 Dimmit 1979 2007 0.10 0.12 08210000 Live Oak 1984 2007 35 36 2106 Nueces River 08206910 Live Oak 1992 2008 29 35 08208000 Live Oak 1979 2007 0.44 1.0 2107 Atascosa River 08207500 Atascosa 2003 2008 2.0 2.4 * 2108 San Miguel Creek 08206700 McMullen 1979 2007 0.10 0.16 *** 2109 Leona River 08204005 Uvalde 2003 2008 9.7 27 2110 Sabinal River 08198500 Uvalde 1980 2008 0.63 1.2 2111 Sabinal River 08198000 Uvalde 1980 2008 8.8 1.8 08192000 Uvalde 1980 2008 15 25 2112 Nueces River 08190000 Uvalde 1980 2008 41 74 *** 2113 Frio River 08195000 Uvalde 1924 2008 13 31 1978 2005 08200720k Medina 0.10* 0.10* 2114 Hondo Creek 2007 2008 08200000 Medina 1980 2008 1.0 1.0 * 08202700 Medina 1980 2008 0.10 0.10* 2115 Seco Creek 08201500 Medina 1980 2008 0.71 0.56 08206600 McMullen 1979 2007 0.11 0.67 2117 Frio River 08205500 Frio 1979 2007 0.10* 1.0 * 08197500 Uvalde 1980 2008 0.10 0.10*

Period of Crit. Low- Harmonic Seg- Stream/River Gage County Record Flow Mean ment Starts Ends (ft3/s) Flow (ft3/s) 08473700 Cameron 1980 2008 51 173 08469200 Hidalgo 1980 2008 260 796 2302 Rio Grande 08464700 Starr 1980 2008 346 1228 08461300 Zapata 1980 2008 175 538 08459200 Webb 1998 2007 615 1320 08459000 Webb 1980 2008 853 1771 08458700 Maverick 1980 2008 970 1805

2304 Rio Grande 1980 1988 08458000 Maverick 929 1741 1989 2008 08455700 Maverick 1980 2008 119 359 08451800 Val Verde 1980 2008 732 1373 08450900 Val Verde 1980 2008 660 1207 08377200 Val Verde 1995 2008 224 468 2306 Rio Grande 08375000 Brewster 1995 2008 26 97 08374200 Presidio 1995 2008 37 115 08371500 Presidio 1980 2008 13 23 2307 Rio Grande 08371200 Presidio 1980 2008 12 24 08370500 Hudspeth 1980 2008 31 66 2309 Devils River 08449400 Val Verde 1960 2008 37** 209 2310 Pecos River 08447410 Val Verde 1980 2008 83 148 08446500 Pecos 1980 2008 6.9 18 2311 Pecos River 08412500 Reeves 1980 2008 5.9 13 ** 2313 San Felipe Creek 08453000 Val Verde 1931 2008 8.1 50 08365000 El Paso 1980 2008 2.1 6.9 2314 Rio Grande 08364000 El Paso 2003 2008 13 35

* Calculated flow is less than 0.10 ft3/s. ** Critical low-flow value is the 0.1% probability value derived from a lognormal distribution for the given period of record at the USGS gage. *** Critical low-flow value is the 5th percentile of the data for the given period of record at the USGS gage. † 7Q2 is estimated as the 10th percentile value of the available flow data. a Data from U.S. Army Corp of Engineers – gated releases from Lake Wright Patman. b 1968-1989 data from discontinued USGS gage 07344500. c 1978-1989 data from discontinued USGS gage 08040500. d Data from U.S. Army Corp of Engineers – gated releases from Richland-Chambers Reservoir. e Data from U.S. Army Corp of Engineers – gated releases from Ray Roberts Lake. f 1978-1995 data from discontinued USGS gage 08068520. g 1965-1992 data from discontinued USGS gage 08077000.

h 1978-1989 data from discontinued USGS gage 08088600. i 1978-1996 data from discontinued USGS gage 08109000. j Daily average flows from each gage were added together, then the 7Q2 and harmonic mean flows were determined using the combined flows. k 1978-2005 data from discontinued USGS gage 08200700.

Appendix D. Segment-Specific Values for Total Suspended Solids, pH, Total Hardness, Total Dissolved Solids, Chloride, and Sulfate.

Tables D-1 – D-25 Segment-Specific Values for Total Suspended Solids, pH, Total Hardness, Total Dissolved Solids, Chloride, and Sulfate.

Notes on tables:

1) Total suspended solids (TSS), pH, and total hardness are 15th percentile values. 2) Total dissolved solids (TDS), chloride, and sulfate are 50th percentile values. 3) Unless otherwise noted, only data from the segment itself has been used in the calculation. If less than 30 data values are available for a particular parameter for the segment, data from tributaries, other segments, the basin, or other basins may be used. These cases are footnoted for each table. The two cases that arise most often are footnoted throughout the tables as follows: (a) Basin-specific value (b) Calculated as (0.65)×(50th percentile conductivity for segment)

Table D-1 Segment-Specific Values for Basin 1, Canadian River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0101 6.0 7.6 233 (a) 2640 830 376

0102 2.0 8.2 223 1260 360 289 0103 13 7.9 246 2535 740 389

0104 2.0 7.8 233 (a) 676 242 62 (a) 0105 28 8.1 209 816 60 51

Table D-2 Segment-Specific Values for Basin 2, Red River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0201 27 7.1 175 (c) 610 147 117

0202 19 7.3 175 (c) 784 197 150 (c) 0203 3.0 7.9 175 1070 345 228

0204 31 7.8 552 (a) 2880 1080 605 0205 29 7.8 937 4510 1800 1095 0206 11 7.6 1100 (d) 12900 6290 2355

0207 16 7.6 1925 15900 15000 3000 (e) (b) 0208 10 6.9 44 72 5.0 14

0209 4.0 7.1 44 (e) 101 7.0 14

0210 3.0 7.9 44 (e) 462 (b) 143 41 (e) 0211 16 7.3 44 364 70 12

0212 4.9 8.0 44 (e) 494 (b) 127 13 (e) (b) 0213 5.0 8.1 44 289 49 14

0214 19 7.6 780 (f) 2951 1200 573

0215 5.0 7.7 780 (f) 3042 (b) 1103 714 (b) 0216 5.0 7.6 770 3088 1130 744

Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0217 3.0 7.8 780 (f) 2940 1100 751

0218 6.0 7.7 1100 8060 4365 2195

0219 23 7.6 168 (g) 1002 (b) 390 118 (h) 0220 5.0 7.6 1120 18200 9255 2630

0221 8.0 7.5 1120 (h) 2616 (b) 735 1070

0222 4.0 7.7 1300 2760 270 1380 (g) 0223 2.0 7.9 168 416 46 88

0224 5.0 7.6 330 (i) 1650 439 481

0225 12 6.5 44 (e) 96 (b) 15 6.0 (b) 0226 9.0 7.5 2300 16250 9500 2800

0227 7.9 (j) 7.5 (j) 1120 (h) 2398 (b, j) 640 (j) 1020 (j)

0228 2.0 8.1 168 (g) 416 11 94

0229 5.0 7.6 330 (i) 1280 290 292

0230 8.0 7.5 1120 (h) 7600 3510 1690

(c) Data from Segments 0201, 0202, and 0203 (d) Data from Segments 0205 and 0207 (e) Data from Segments 0208, 0209, 0210, 0211, 0212, and 0213 (f) Data from Segments 0214, 0215, 0216, and 0217 (g) Data from Segments 0207 (tributary lake only), 0210, 0212, 0213, 0219, 0223, and 0228 (h) Data from Segments 0218, 0220, 0221, 0227, and 0230 (i) Data from Segments 0224 and 0229 (j) Data from Segments 0221 and 0227

Table D-3 Segment-Specific Values for Basin 3, Sulphur River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0301 10 6.9 54 (a) 150 11 18 (a) 0302 8.6 7.2 54 137 10 17

0303 22 7.1 54 (a) 219 15 34

0304 2.5 6.5 54 (a) 262 60 32 (a) 0305 5.6 7.5 54 490 30 150

0306 24 7.5 54 (a) 326 29 54 (a) 0307 9.0 7.5 54 143 5.7 12

Table D-4 Segment-Specific Values for Basin 4, Cypress Creek Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0401 3.0 6.0 19 84 13 12

0402 3.0 6.1 22 86 13 16 0403 2.5 6.5 25 99 14 23 0404 6.0 6.5 42 220 32 42 0405 3.0 6.6 29 86 15 16 0406 4.5 6.0 19 (a) 82 9.0 6.0 0407 5.0 5.9 12 72 15 5.0

0408 2.0 7.1 24 (a) 91 15 22 (a) 0409 5.0 6.2 19 116 16 14

0410 3.8 5.9 19 (a) 80 6 6

Table D-5 Segment-Specific Values for Basin 5, Sabine River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0501 6.0 6.7 28 618 (b) 179 44

0502 13 6.5 24 107 15 15 0503 5.0 6.7 29 117 16 16 0504 1.5 6.7 28 126 17 16 0505 16 6.7 42 237 39 26 0506 18 6.8 49 201 32 27 0507 5.0 7.6 64 130 5.0 11

0508 11 6.4 42 378 86 28 (a) 0509 5.0 6.9 32 123 21 22

0510 2.0 6.3 28 90 15 15 0511 8.0 6.2 31 704 185 26 0512 1.5 7.0 40 128 15 17 0513 5.0 6.1 12 31 (b) 5.0 3.0 0514 3.3 6.4 24 120 19 15 0515 12 6.7 45 230 40 32

Table D-6 Segment-Specific Values for Basin 6, Neches River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0601 8.0 6.6 38 (a) 2240 600 101

0602 17 6.5 27 112 18 19 (a) 0603 8.0 6.5 27 115 17 19

0604 10 6.5 36 92 24 20 (a) 0605 4.0 6.8 27 143 25 24

0606 5.0 6.4 42 (c) 232 34 36

0607 10 6.5 26 168 22 8.0

0608 6.0 6.0 14 83 14 5.0

0609 2.0 6.4 22 91 (b) 15 18

0610 2.0 6.9 27 (a) 90 16 20 (c) 0611 8.0 6.4 38 134 19 22

0612 9.3 6.5 20 (a) 100 10 16 (a) 0613 2.0 6.8 27 71 11 8.8

0614 1.0 7.1 27 (a) 61 7.0 6.0

0615 8.0 6.6 27 (a) 193 30 35

(c) Data from tributaries included.

Table D-7 Segment-Specific Values for Basin 7, Neches-Trinity Coastal Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0701 12 6.7 56 246 54 32 (c) 0702 14 6.8 288 10872 4700 690

0703 11 6.6 288 (c) 9000 4780 650

0704 12 6.7 74 249 56 33

(c) Data from Segments 0702 (including tributaries), 0703, 2411, and 2412

Table D-8 Segment-Specific Values for Basin 8, Trinity River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0801 18 7.3 84 224 36 33

0802 9.0 7.4 94 205 26 35

0803 7.3 7.4 94 240 29 43

0804 41 7.2 122 338 42 60

0805 23 7.2 148 408 52 77

Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0806 10 7.5 136 287 35 38 (a) 0807 6.9 7.9 96 231 34 26

0808 5.0 7.5 98 (a) 260 (b) 36 23 (a) 0809 5.0 7.9 96 249 34 26

0810 16 7.5 98 (a) 425 53 39

0811 2.0 7.9 96 (a) 212 28 20 (a) 0812 28 7.2 98 490 59 36

0813 1.5 6.8 96 (a) 73 11 9.0

0814 18 7.5 120 (c) 349 23 70 (a) (b) 0815 6.1 7.9 96 202 14 35

0816 4.7 7.8 96 (a) 179 (b) 8.0 17 (b) 0817 6.1 7.9 110 208 11 31

0818 5.4 7.5 96 (a) 121 14 24 0819 16 7.3 119 372 45 47 0820 5.0 7.8 98 190 15 26 0821 5.0 7.8 96 (a) 216 8.0 23 0822 13 7.5 116 259 24 41 0823 6.0 7.8 106 208 19 30

0824 7.0 7.6 77 422 49 49 (d) 0825 5.0 7.5 118 231 25 35

0826 5.0 7.9 118 208 24 30 0827 8.7 7.5 96 (a) 188 (b) 13 31 0828 6.0 7.9 100 187 18 28 0829 8.0 7.5 98 (a) 289 22 33 0830 6.0 7.9 96 (a) 205 22 27 0831 5.0 7.5 160 408 42 45

0832 5.0 8.0 96 (a) 283 (b) 41 31 (a) 0833 6.7 7.5 98 561 92 67

0834 2.0 7.7 96 (a) 182 (b) 27 12 0835 10 (e) 7.3 (e) 120 (c) 232 (e) 28 (e) 40 (e) 0836 2.0 7.7 96 (a) 170 11 33 0837 10 (e) 7.3 (e) 120 (c) 232 (e) 28 (e) 40 (e)

0838 4.0 7.9 153 342 21 102 (a) (b) 0839 9.0 7.6 98 188 20 22

Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0840 4.0 7.7 95 179 18 16

0841 16 7.3 160 467 74 68

(c) Data from Segments 0814 (including tributaries), 0835, and 0837 (d) Data from Segments 0825 and 0826 (e) Data from Segments 0835 and 0837

Table D-9 Segment-Specific Values for Basin 9, Trinity-San Jacinto Coastal Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 0901 18 7.4 930 (c) 8400 2875 261

0902 3.0 7.1 40 (d) 373 83 17

(c) Data from Segment 2426 (d) Data from Basin 10

Table D-10 Segment-Specific Values for Basin 10, San Jacinto River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1001 8.0 7.5 44 940 2765 246

1002 10 7.0 46 186 25 9.0

1003 7.0 6.6 37 144 32 5.0

1004 11 6.9 65 187 38 10

1005 11 7.5 620 10800 6190 838

1006 10 7.2 412 2920 2090 215

1007 8.0 7.1 108 1100 482 94

1008 10 6.8 48 241 47 10

1009 13 7.0 44 388 57 19

1010 5.0 6.6 28 99 15 5.0

1011 3.0 6.4 21 88 17 4.0

1012 3.0 7.3 65 131 17 6.0

1013 14 7.2 78(a) 381 60 24

1014 17 7.1 40(a) 368 64 23 (a) (b) 1015 10 6.6 40 168 43 9.7

1016 12 7.5 40(a) 456 82 38 (a) 1017 10 7.6 40 463 86 33

Table D-11 Segment-Specific Values for Basin 11, San Jacinto-Brazos Coastal Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1101 15 7.5 134 1720 460 92

1102 15 7.4 126 568 125 38

1103 9.6 7.3 125 3142 1550 234 (a) 1104 12 7.3 116 493 99 58

1105 15 7.3 118 (a) 3149 2065 289

1107 19 7.6 118 (a) 10650 5327 705 (a) 1108 11 7.4 116 474 116 46

1109 15 7.5 118 (a) 7405 2590 411 (a) 1110 15 7.3 116 346 71 30

1111 9.0 7.9 3697 27700 14161 2020 1113 18 7.4 118 (a) 1913 902 120

Table D-12 Segment-Specific Values for Basin 12, Brazos River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1201 10 7.7 232 (c) 5150 3220 412

1202 36 7.6 160 438 88 60

1203 3.0 7.9 230 (d) 888 371 180 (d) 1204 4.3 7.8 230 1294 485 234

1205 4.0 7.9 230 (d) 1418 893 311

1206 7.0 7.8 230 (d) 1724 692 348 (d) 1207 2.0 8.1 230 1870 893 371

1208 17 7.7 473 (e) 4267 2000 900 (f) 1209 17 7.1 68 235 44 42

1210 19 7.6 68 (f) 182 10 14

1211 22 7.3 160 (a) 275 53 64 (a) 1212 7.0 7.6 120 256 46 59

1213 23 7.7 171 (g) 332 42 36

1214 17 7.5 170 (h) 392 25 30 (g) 1215 2.0 7.7 171 284 39 19

1216 2.0 8.1 171 (g) 257 55 22 (g) 1217 2.0 7.9 171 372 70 24

1218 4.0 7.2 171 (g) 390 53 46 1219 6.8 7.2 171 (g) 340 38 33

Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1220 2.0 8.0 120 (a) 223 31 27 (a) 1221 11 7.6 160 396 70 48

1222 7.0 7.9 120 (a) 410 100 54 (a) 1223 4.0 7.6 160 639 232 75

1224 4.0 7.9 120 (a) 296 73 46

1225 5.0 7.9 124 217 16 25 (a) 1226 3.0 7.7 160 282 23 26

1227 4.4 7.4 160 (a) 386 42 52

1228 8.0 7.9 120 (a) 202 (b) 13 16 (a) 1229 2.0 7.9 160 336 24 45

1230 5.0 8.0 230 (d) 298 (b) 39 37 (d) (b) 1231 5.0 8.0 230 416 123 24

1232 16 7.6 584 1800 520 778

1233 3.0 7.9 218 715 (b) 244 61 (a) (b) 1234 2.0 7.9 120 263 29 36

1235 10 7.9 120 (a) 716 (b) 162 182

1236 5.0 8.0 203 458 (b) 94 78 (a) (b) 1237 5.0 7.9 120 699 186 125

1238 8.7 7.5 1525 (i) 37367 16000 2505 (j) (j) (a) (j) (j) 1239 4 8.1 160 606 111 48 (j)

1240 4.0 8.1 120 (a) 606 111 47

1241 9.9 7.7 473 (e) 4325 1400 1340 (k) 1242 11 7.7 221 693 179 103

1243 0.5 7.3 160 (a) 296 12 16 1244 2.0 7.6 160 (a) 369 53 38 1245 12 7.4 140 352 70 46

1246 3.0 7.7 160 (a) 327 16 52 (a) 1247 8.0 7.9 120 229 20 24

1248 3.0 7.7 170 (h) 291 18 20

1249 2.0 7.9 120 (a) 202 12 16 (h) 1250 0.5 7.7 170 270 17 21

1251 1.0 7.8 170 (h) 270 13 21

1252 4.0 7.4 68 (f) 132 20 16 (f) 1253 10 7.4 68 208 20 14

Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1254 5.0 7.9 120 (a) 228 12 54 (a) 1255 3.5 7.6 160 501 111 44

1256 5.0 7.7 177 574 219 91 (l) 1257 3.7 7.6 251 780 312 144

(c) Data from Segments 1201 and 1401 (d) Data from Segments 1203, 1204, 1205, 1206, 1207, 1230, and 1231 (e) Data from Segments 1208 and 1241 (f) Data from Segments 1209, 1210, 1252, and 1253 (g) Data from Segments 1213, 1215, 1216, 1217, 1218, 1219, and tributaries to these segments (h) Data from Segments 1214, 1248, 1250, 1251, and tributaries to Segments 1247 and 1249 (i) Data from Segment 1238 and its tributaries (j) Data from Segments 1239 and 1240 (k) Data from Segment 1242 and from stations 12039, 12040, 12041, and 14226 in Segment 1256 (l) Data from Segment 1257 and from station 12042 in Segment 1256

Table D-13 Segment-Specific Values for Basin 13, Brazos-Colorado Coastal Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1301 13 7.3 135 (a) 2300 2745 215

1302 19 7.0 96 (a) 267 48 16 (a) 1304 13 7.4 135 1080 190 62

1305 13 7.3 96 (a) 329 41 12

Table D-14 Segment-Specific Values for Basin 14, Colorado River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1401 12 7.7 232 (c) 7584 473 110

1402 12 7.8 200 336 51 41

1403 1.0 7.7 180 (d) 298 55 36 (d) 1404 1.0 8.0 180 300 57 36

1405 2.0 7.8 180 (d) 332 66 40

1406 3.0 7.9 180 (d) 332 67 41 (d) 1407 2.0 7.8 180 418 100 67

1408 2.0 8.1 180 (d) 422 100 64

1409 15 7.8 237 (e) 434 84 56 (f) (g) (g) 1410 14 7.7 320 788 260 177 (g)

1411 5.0 7.9 318 (h) 2473 740 465

1412 16 7.6 310 4600 1635 961

1413 7.0 7.8 188 (a) 367 (b) 47 63

1414 5.0 8.0 188 362 52 32

Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1415 2.0 7.9 163 (i) 222 21 13 (i) 1416 8.0 7.8 163 307 24 17

1417 13 7.8 190 (a) 524 (b) 109 68 (a) 1418 5.0 7.9 188 296 71 38

1419 2.8 8.0 188 (a) 317 72 47

1420 9.4 7.6 190 (a) 462 91 81

1421 12 7.7 317 1080 447 243

1422 10 8.0 312 896 290 103

1423 5.0 8.0 188 (a) 434 102 47

1424 2.5 7.6 240 362 48 15

1425 5.0 8.0 217 (j) 474 (b) 120 54 (k) (g) (g) 1426 14 7.8 315 2190 776 720 (g)

1427 1.0 7.4 163 (i) 300 24 37

1428 3.0 7.4 190 (l) 334 55 41 (a) 1429 1.2 7.4 188 315 49 37

1430 0.5 7.2 194 306 23 30

1431 5.0 7.3 190 (a) 652 186 88 (a) 1432 5.0 7.6 190 464 96 68

1433 3.0 8.1 321 (m) 1165 371 287 (l) 1434 5.0 7.8 190 340 56 44

(c) Data from Segments 1201 and 1401 (d) Data from Segments 1403, 1404, 1405, 1406, 1407, and 1408 (e) Data from Segments 1409, 1410, and 1417 (f) Data from Segments 1410, 1426, and 1433 (g) Data from 1995 to present to reflect changes in the watershed (h) Data from Segments 1411 and 1412 (i) Data from Segments 1415, 1416, and 1427 (j) Data from Segment 1425 and its tributaries (k) Data from Segments 1411, 1412, and 1426 (l) Data from Segments 1428 and 1434 (m) Data from Segments 1421, 1426, and 1433

Table D-15 Segment-Specific Values for Basin 15, Colorado-Lavaca Coastal Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1501 15 7.3 85 (c) 706 384 65

1502 16 7.3 95 (c) 495 114 22

(c) Data from Basins 15 and 16

Table D-16 Segment-Specific Values for Basin 16, Lavaca River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1601 10 7.8 85 (a) 1108 (b) 123 29

1602 6.0 7.7 177 441 68 23

1603 8.0 7.9 82 454 (b) 69 16 (b) 1604 7.4 7.4 57 148 19 7.4

1605 5.3 7.6 141 480 72 15

Table D-17 Segment-Specific Values for Basin 17, Lavaca-Guadalupe Coastal Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1701 27 7.8 85 (c) 3700 974 164

(c) Data from Basin 16

Table D-18 Segment-Specific Values for Basin 18, Guadalupe River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1801 44 7.6 167 (a) 434 70 52

1802 40 7.7 212 460 (b) 63 52

1803 12 7.7 206 325 33 30

1804 4.8 7.7 213 297 18 24

1805 2.0 8.0 161 217 15 19

1806 3.0 7.7 204 290 18 16

1807 3.9 7.7 100 456 78 22

1808 8.0 7.7 225 332 25 28 (c) 1809 2.0 7.6 189 247 13 23

1810 12 7.6 215 673 135 85

1811 1.0 7.4 254 311 17 24

1812 2.0 7.7 184 248 14 19

1813 0.5 7.7 189 266 12 26

1814 2.0 7.5 265 388 (b) 19 24

1815 0.5 7.1 228 299 13 16

1816 2.8 7.7 185 (d) 292 (b) 23 12 (d) (b) 1817 0.5 7.4 185 259 10 5.0

1818 0.5 7.6 185 (d) 266 (b) 10 5.0

(c) Data from Segment 1813 (d) Data from Segments 1816, 1817, and 1818

Table D-19 Segment-Specific Values for Basin 19, San Antonio River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 1901 30 7.7 312 616 100 97

1902 8.8 7.6 257 606 100 149

1903 6.0 7.4 240 372 41 60 (a) 1904 2.7 7.9 204 262 13 45

1905 2.0 7.6 240 339 13 76

1906 5.0 7.3 253 465 63 68 (a) (b) 1907 0.5 7.4 204 402 21 43

1908 1.0 7.4 204 (a) 302 18 27 (a) 1909 1.2 7.3 204 258 14 44

1910 2.2 7.2 204 374 45 53

1911 5.0 7.4 202 477 54 54 (a) 1912 12 7.9 204 420 68 66

1913 5.0 7.2 256 500 60 45

Table D-20 Segment-Specific Values for Basin 20, San Antonio-Nueces Coastal Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 2001 14 7.6 241 (a) 1780 1080 82

2002 10 7.5 243 1060 530 40 2003 12 7.6 241 (a) 810 193 40 2004 8.1 7.4 240 (a) 889 279 54

Table D-21 Segment-Specific Values for Basin 21, Nueces River Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 2101 23 7.9 160 (a) 12150 2250 350

2102 10 7.8 164 431 132 49 2103 6.0 7.8 149 568 111 53 2104 8.0 7.6 137 452 105 42 2105 5.0 7.6 160 (a) 316 49 40 2106 15 7.6 158 498 128 75 2107 13 7.5 130 1080 242 225

2108 11 7.4 201 840 218 277 (c) 2109 10 7.5 226 508 73 128

2110 2.0 7.2 226 (c) 560 100 40

Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 2111 0.5 7.6 226 (c) 276 12 27

2112 0.5 7.6 190 242 16 15

2113 0.5 7.7 160 (a) 238 11 14 (a) 2114 0.5 7.7 160 252 12 34

2115 0.5 7.7 160 (a) 248 12 41

2116 4.0 7.8 167 494 146 73

2117 7.0 7.5 185 935 259 167

(c) Data from Segments 2109, 2110, and 2111

Table D-22 Segment-Specific Values for Basin 22, Nueces-Rio Grande Coastal Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 2201 12 7.7 675 (a) 7950 3778 1150

2202 72 7.4 713 2780 860 770 (a) 2203 36 7.9 675 14200 10605 984

2204 15 7.3 653 (a) 13900 (c) 3300 (c) 598 (c)

(c) Data from 1995 to present to reflect changes in the watershed

Table D-23 Segment-Specific Values for Basin 23, Rio Grande Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 2301 15 7.7 255 880 210 283

2302 5.9 7.6 240 712 146 247

2303 5.0 7.9 230 (a) 561 114 221

2304 5.0 7.7 237 650 117 212

2305 2.0 7.9 230 (a) 650 115 215

2306 47 7.4 251 1125 142 403

2307 39 7.5 229 1453 411 460

2308 20 7.7 224 775 126 223

2309 1.0 7.7 230 (a) 224 14 9.0

2310 4.0 7.7 510 2236 853 494

2311 6.0 7.6 2203 9840 4030 2381 (c) 2312 6.0 7.8 1973 5455 1954 1550

2313 4.0 7.5 230 (a) 285 18 20

2314 24 7.8 240 718 110 224

(c) Data from Segment 2312 and from station 13265 in Segment 2311

Table D-24 Segment-Specific Values for Basin 24, Bays and Estuaries Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 2411 11 6.8 950 (a) 12800 7150 1010

2412 8.3 6.8 950 (a) 6790 3598 496 2421 11 7.8 787 13400 7842 1060 2422 8.0 7.8 148 7785 3290 460 2423 13 7.8 950 (a) 12800 7170 960 2424 13 7.8 3112 26099 13100 1789 2425 16 7.9 700 12846 6000 778 2426 16 7.6 930 12459 5970 814 2427 12 7.6 730 11915 5675 810 2428 16 7.9 1037 12870 6400 838 2429 9.0 7.5 644 10501 5625 815 2430 9.0 7.6 603 9670 4979 712 2431 15 7.7 1727 (c) 19412 8350 1171

2432 13 7.7 3163 (d) 21600 9759 1378 (d) (b) 2433 10 7.8 3163 24862 13200 1860

2434 14 7.9 3163 (d) 27100 14240 1940 (d) (b) 2435 27 7.8 3163 25415 13825 1880

2436 11 7.7 1002 13960 6545 900

2437 11 7.9 2867 24250 12200 1670 (e) 2438 10 7.7 1466 14000 6980 1025

2439 12 7.9 1606 19300 10500 1430

2441 25 7.8 1185 (f) 23600 11150 1465 (f) (b) 2442 20 7.7 1185 20215 11800 1295

2451 11 7.9 1185 (f) 26000 13400 1850 (f) 2452 12 7.8 1185 22150 11500 1600

2453 11 7.9 980 19200 9860 1340

2454 12 7.9 1185 (f) 22700 11780 1630 (f) 2455 11 8.0 1185 24450 12025 1597

2456 28 7.9 950 (a) 4260 2518 393

2461 10 7.9 950 (a) 26200 14100 1950 (a) 2462 16 8.0 950 10450 6970 960

2463 17 7.9 950 (a) 19800 10200 1365 (a) 2471 9.0 7.9 950 28600 14500 2000

2472 15 7.9 950 (a) 15500 7500 1012

Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 2473 16 7.8 950 (a) 19725 10000 1400 (g) 2481 10 7.9 5011 34850 17100 2400

2482 17 7.8 5011 (g) 30900 15800 2150 (g) 2483 13 7.9 5011 29650 15873 2220

2484 10 7.9 5011 (g) 33800 16800 2380

2485 33 7.7 5011 (g) 30850 17400 2400 (g) 2491 12 8.0 5011 36925 18700 2666

2492 17 7.9 5011 (g) 40050 21100 3095

2493 13 7.9 5011 (g) 37350 19250 2650 (g) 2494 10 7.9 5011 35950 18335 2565

(c) Data from Segments 2431 and 2439 (d) Data from Segments 2424, 2432, 2433, 2434, and 2435 (e) Data from Segment 2438 and from stations 13303 and 13304 in Segment 2421 (f) Data from Segments 2441, 2442, 2451, 2452, 2453, 2454, and 2455 (g) Data from Segments 2481, 2482, 2483, 2484, 2485, 2491, 2492, 2493, and 2494

Table D-25 Segment-Specific Values for Basin 25, Gulf of Mexico Segment TSS pH Total Hardness TDS Chloride Sulfate Number (mg/L) (s.u.) (mg/L as CaCO3) (mg/L) (mg/L) (mg/L) 2501 12 7.0 4613 28700 15500 2170

Appendix E. Minimum Analytical Levels and Suggested Analytical Methods.

Table E-1. Minimum Analytical Levels (MALs) and Suggested Methods for Permit Application Screening

Notes on table: 1) MALs, screening levels, and suggested methods in this table may be used for effluent screening.

2) This table includes pollutants in § 307.6 of the Standards, all 126 priority pollutants, and those pollutants listed in 40 CFR Part 122, Appendix D, Table 5.

3) Suggested analytical methods have traditionally been EPA-approved analytical methods either in the 40 CFR Part 136, as amended, or in EPA-published documents pertaining to wastewater matrices, or methods developed and published by the TCEQ or other government agencies for wastewater. Applicants and permittees may use any analytical method approved in 40 CFR Part 136 that is sufficiently sensitive to demonstrate compliance with permit application screening requirements.

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) Acenaphthene 83-32-9 10 625

Acenaphthylene 208-96-8 10 625 Acetaldehyde 75-07-0 50 1667 Acrolein 107-02-8 50 624 Acrylonitrile 107-13-1 50 1624B3 Aldrin 309-00-2 0.01 608 Allyl alcohol 107-18-6 50 16243 Allyl chloride 107-05-1 10 16243 Aluminum, total 7429-90-5 2.5 200.8 4 Amyl acetate 628-63-7 5 1666 3 Aniline 62-53-3 10 625 11 Anthracene 120-12-7 10 625 Antimony, total 7440-36-0 5 200.8 4 Arsenic, total 7440-38-2 0.5 200.8 4 Asbestos 1332-21-4 Not Specified 12 100.1 and 100.2 13 Barium, total 7440-39-3 3 200.8 4 Benzene 71-43-2 10 624 Benzidine 92-87-5 50 625 Benzo(a)anthracene 56-55-3 5 625 Benzo(a)pyrene 50-32-8 5 625 Benzo(b)fluoranthene 205-99-2 10 625

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) Benzo(g,h,i)perylene 191-24-2 20 625

Benzo(k)fluoranthene 207-08-9 5 625 Benzonitrile 100-47-0 1 mg/L ASTM D3371 Benzyl chloride 100-44-7 Not Specified 12 TBD 5 Beryllium, total 7440-41-7 0.5 200.8 4 Bis(2-chloroethoxy)methane 111-91-1 10 625 Bis(2-chloroethyl)ether 111-44-4 10 625

Bis(2-chloroisopropyl)ether 108-60-1 10 625 5 Bis(chloromethyl)ether 542-88-1 — —5

Bis(2-ethylhexyl)phthalate 117-81-7 10 625 [Di(2-ethylhexyl)phthalate] Boron, total 7440-42-8 20 100 200.7

Bromide — 400 300.0, Rev. 2.1 300.1, Rev. 1.0

Bromodichloromethane 75-27-4 10 624 [Dichlorobromomethane] Bromoform 75-25-2 10 624

4-Bromophenyl phenyl ether 101-55-3 10 625 Butyl acetate 540-88-5 5 1666 3 n-Butylamine 109-73-9 Not Specified 11 TBD 12 sec-Butylamine 13952-84-6 Not Specified 11 TBD 12 tert-Butylamine 75-64-9 Not Specified 11 TBD 12 Butylbenzyl phthalate 85-68-7 10 625 Cadmium, total 7440-43-9 1 200.8 4 Captan 133-06-2 0.414 SM6630B Carbaryl 63-25-2 5 632 Carbazole 86-74-8 20 1625 3 Carbofuran 1563-66-2 3 632 Carbon disulfide 75-15-0 10 1624 3 Carbon tetrachloride 56-23-5 2 624 Chlordane 57-74-9 0.2 608 Chlorine 7782-50-5 33 4500-Cl E or G Chlorobenzene 108-90-7 10 624 Chlorodibromomethane 124-48-1 10 624

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) Chloroethane 75-00-3 50 624

2-chloroethylvinyl ether 110-75-8 10 624 Chloroform 67-66-3 10 624 2-Chloronaphthalene 91-58-7 10 625 2-Chlorophenol 95-57-8 10 625 4-Chlorophenyl phenyl ether 7005-72-3 10 625 Chlorpyrifos 2921-88-2 0.05 1657 Chromium, total 7440-47-3 3 200.8 4 Chromium, hexavalent 18540-29-9 3 218.6, rev. 3.3 Chromium, trivalent 16065-83-1 —7 —7 Chrysene 218-01-9 5 625 Cobalt, total 7440-48-4 0.3 1500 200.8 4 Copper, total 7440-50-8 2 200.8 4 Coumaphos 56-72-4 0.025 1657 Cresols (all isomers) 1319-77-3 10 625 11 m-Cresol 108-39-4 10 625 11 o-Cresol 95-48-7 10 625 11

p-Cresol 106-44-5 10 625 11 [4-Methylphenol] Crotonaldehyde 4170-30-3 10 16243

Cyanide, total 57-12-5 10 335.4 or 4500-CN D or 4500-CN E

Cyanide, available 57-12-5 10 4500-CN G

2 OIA-1677 Cyclohexane 110-82-7 5 1666 3

4,4’-DDD 72-54-8 0.1 608 4,4’-DDE 72-55-9 0.1 608 4,4’-DDT 50-29-3 0.02 608

2,4-D 17 94-75-7 0.7 615 or SM6640B Danitol 39515-41-8 —8 —8 [Fenpropathrin]

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) n-Decane 124-18-5 30 625 11

Demeton 8065-48-3 0.20 1657 15, 16

Diazinon 333-41-5 0.5 1657 0.1 614 Dibenzo(a,h)anthracene 53-70-3 5 625

1,2-Dibromoethane 106-93-4 10 1624 3, 11 Dicamba 1918-00-9 0.110 1658 15 Dichlobenil 1194-65-6 Not Specified 12 TBD 12 Dichlone 117-80-6 Not Specified 12 1656 13

m-Dichlorobenzene 541-73-1 10 624 [1,3-Dichlorobenzene] o-Dichlorobenzene 95-50-1 10 624 [1,2-Dichlorobenzene] p-Dichlorobenzene 106-46-7 10 624 [1,4-Dichlorobenzene] 3,3'-Dichlorobenzidine 91-94-1 5 625

1,1-Dichloroethane 75-34-3 10 624 1,2-Dichloroethane 107-06-2 10 624

1,1-Dichloroethene 75-35-4 10 624 [1,1-Dichloroethylene] Dichloromethane 75-09-2 20 624 [Methylene choride] 2,4-Dichlorophenol 120-83-2 10 625

1,2-Dichloropropane 78-87-5 10 624 1,3-Dichloropropene 542-75-6 10 624

2,2-Dichloropropionic acid 75-99-0 2 615 [Dalapon] Dichlorvos 62-73-7 0.004 1657

Dicofol 115-32-2 1 ASTM D5812- [Kelthane] 96(02)

Dieldrin 60-57-1 0.02 608 Diethyl amine 109-89-7 50 mg/L 1671 Diethyl phthalate 84-66-2 10 625 Dimethyl amine 124-40-3 50 mg/L 1671 2,4-Dimethylphenol 105-67-9 10 625 Dimethyl phthalate 131-11-3 10 625 Di-n-butyl phthalate 84-74-2 10 625 Dinitrobenzene 25154-54-5 10 1625 3

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) 2,4-Dinitrophenol 51-28-5 50 625

2,4-Dinitrotoluene 121-14-2 10 625 2,6-Dinitrotoluene 606-20-2 10 625 Di-n-octyl phthalate 117-84-0 10 625

Dioxins/Furans [TCDD Equivalents] (ppq) 1613B 2,3,7,8-TCDD 1746-01-6 10 1,2,3,7,8-PeCDD 40321-76-4 50 2,3,7,8-HxCDDs 1,2,3,4,7,8-HxCDD 39227-28-6 50 1,2,3,6,7,8-HxCDD 57653-85-7 50 1,2,3,7,8,9-HxCDD 19408-74-3 50 1,2,3,4,6,7,8-HpCDD 35822-46-9 50 OCDD 3268-87-9 100 2,3,7,8-TCDF 51207-31-9 10 1,2,3,7,8-PeCDF 57117-41-6 50 2,3,4,7,8-PeCDF 57117-31-4 50 2,3,7,8-HxCDFs 1,2,3,4,7,8-HxCDF 70648-26-9 50 1,2,3,6,7,8-HxCDF 57117-44-9 50 1,2,3,7,8,9-HxCDF 72918-21-9 50 2,3,4,6,7,8-HxCDF 60851-34-5 50 2,3,4,7,8-HpCDFs 38998-75-3 1,2,3,4,6,7,8-HpCDF 67562-39-4 50 1,2,3,4,7,8,9-HpCDF 55673-89-7 50 OCDF 39001-02-0 100 1,2-Diphenylhydrazine (as Azobenzene) 122-66-7 20 1625 3

Diquat 2764-72-9 1.5 549, 549.1 Disulfoton 298-04-4 0.032 1657 Diuron 330-54-1 0.090 632 Endosulfan I (alpha) 959-98-8 0.01 608 Endosulfan II (beta) 33213-65-9 0.02 608 Endosulfan sulfate 1031-07-8 0.1 608 Endrin 72-20-8 0.02 608 Endrin aldehyde 7421-93-4 0.1 608 Epichlorohydrin 106-89-8 1 mg/L ASTM D-3695 15 Ethion 563-12-2 0.02 1657 Ethylbenzene 100-41-4 10 624 Ethylene diamine 107-15-3 Not Specified 12 TBD 12 Ethylene dibromide 106-93-4 10 1624 3 Formaldehyde 50-00-0 50 1667 Fluoranthene 206-44-0 10 625 Fluorene 86-73-7 10 625

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) Fluoride 16984-48-8 500 300.0, 300.1

Furfural 98-01-1 50 mg/L 1667

Guthion 86-50-0 0.1 1657 [Azinphos Methyl] Heptachlor 76-44-8 0.01 608

Heptachlor epoxide 1024-57-3 0.01 608 Hexachlorobenzene 118-74-1 5 625 Hexachlorobutadiene 87-68-3 10 625 alpha-Hexachlorocyclohexane 319-84-6 0.05 608 beta-Hexachlorocyclohexane 319-85-7 0.05 608

gamma-Hexachlorocyclohexane 58-89-9 0.05 608 [Lindane] delta-Hexachlorocyclohexane 319-86-8 0.05 608

Hexachlorocyclopentadiene 77-47-4 10 625 or 1625B 3, 17 Hexachloroethane 67-72-1 20 625 Hexachlorophene 70-30-4 10 604.1 Indeno(1,2,3-cd)pyrene 193-39-5 5 625 Iron, total 7439-89-6 7 300 200.7

Isophorone 78-59-1 10 625 12 Isopropanolamine dodecylbenzenesulfonate 42504-46-1 Not Specified TBD 12

Kepone 143-50-0 0.3 1656 Lead, total 7439-92-1 0.5 200.8 4

Malathion 17 121-75-5 0.1 1657 or SM6630C Magnesium, total 7439-95-4 20 200.7

Manganese, total 7439-96-5 0.5 50 200.8 4

Mercaptodimethur 2032-65-7 0.06 632 15 [Methiocarb] Mercury, total9, 10 7439-97-6 0.005 245.7, Rev. 2.0

0.0005 1631E

Methoxychlor 18 72-43-5 2.0 617 or SM6630B and C Methyl bromide 74-83-9 50 624 [Bromomethane] Methyl chloride 74-87-3 50 624 [Chloromethane]

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) Methyl ethyl ketone 78-93-3 50 624 12 Methyl mercaptan 74-93-1 Not Specified TBD 12

Methyl methacrylate 80-62-6 10 1624

Methyl parathion 17 298-00-0 0.05 1657 or SM6630C Mevinphos 7786-34-7 0.2 1657

Mexacarbate 315-18-4 1.5 632 Mirex 2385-85-5 0.02 SM6630B and C 17 Molybdenum, total 7439-98-7 1 500 200.8 3 Monoethyl amine 75-04-7 Not Specified 12 TBD 12 Monomethylamine 74-89-5 50 mg/L 1667 Naled 300-76-5 0.05 1657 Napthalene 91-20-3 10 625 Napthenic acid 1338-24-5 Not Specified 12 TBD 12 Nickel, total 7440-02-0 2 200.8 4

Nitrate-nitrogen 14797-55-8 100 300.0, Rev. 2.1 300.1, Rev. 1.0

Nitrobenzene 98-95-3 10 625 2-Nitrophenol 88-75-5 20 625 4-Nitrophenol 100-02-7 50 625 N-Nitrosodiethylamine 55-18-5 20 625 N-Nitrosodimethylamine 62-75-9 50 625 or 1625B 3 N-Nitroso-di-n-butylamine 924-16-3 20 625 N-Nitroso-di-n-propylamine 621-64-7 20 625 or 1625B 3 N-Nitrosodiphenylamine 86-30-6 20 625 or 1625B 3 Nitrotoluene 1321-12-6 Not Specified 12 TBD 12 Nonylphenol 104-40-5 333 1625 para-Nonylphenol 84852-15-3 333 1625 Nonylphenol 25154-52-3 333 1625 n-Octadecane 593-45-3 30 625 11

Parathion (ethyl) 17 56-38-2 0.1 1657 or SM6630C Pentachlorobenzene 608-93-5 20 625

Pentachlorophenol 87-86-5 5 625

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) Phenanthrene 85-01-8 10 625

Phenol, total 108-95-2 10 625 p-Phenolsulfonate 127-82-2 Not Specified 12 TBD 12 Phosgene 75-44-5 — 8, 12 Degrades in water8

Polychlorinated biphenyls (PCBs) 1336-36-3 PCB-77 32598-13-3 0.0005 1668B 19 PCB-81 70362-50-4 0.0005 1668B 19 PCB-126 57465-28-8 0.0005 1668B 19 PCB-169 32774-16-6 0.0005 1668B 19 PCB-1016 12674-11-2 0.2 608 PCB-1221 11104-28-2 0.2 608 PCB-1232 11141-16-5 0.2 608 PCB-1242 53469-21-9 0.2 608 PCB-1248 12672-29-6 0.2 608 PCB-1254 11097-69-1 0.2 608 PCB-1260 11096-82-5 0.2 608 Propargite 2312-35-8 0.02 GCMS

Propylene oxide 75-56-9 25 624 Heated Purge Pyrene 129-00-0 10 625 Pyrethrin I 121-21-1 3.1 1660 Pyrethrin II 121-29-9 3.3 1660 Pyridine 110-86-1 20 625 11 Quinoline 91-22-5 1 mg/L ASTM D-4763 Resorcinol 108-46-3 100 1625 3 Selenium, total 7782-49-2 5 200.8 4 Silver, total 7440-22-4 0.5 200.8 4 Strontium 7440-24-6 1.0 200.7 Strychnine 57-24-9 40 1625 3 Styrene 100-42-5 10 1625 3 1,2,4,5-Tetrachlorobenzene 95-94-3 20 1625 3 1,1,2,2-Tetrachloroethane 79-34-5 10 624

Tetrachloroethene 127-18-4 10 624 [Tetrachloroethylene] Thallium, total 7440-28-0 0.5 200.8 4

Tin, total 7440-31-5 5 200.7, 200.9 4 Titanium, total 7440-32-6 30 40 283.2 Toluene 108-88-3 10 624

Screening MAL Suggested Pollutant CASRN 1 Level 2 (μg/L) Method (μg/L) Toxaphene 8001-35-2 0.3 608

2,4,5-TP 93-72-1 0.3 SM6640B [Silvex] 1,2-Trans-dichloroethene 156-60-5 10 624 1,2-Trans-dichloroethylene Tributyltin 688-73-3 0.01 TNRCC 1001 [TBT] 1,2,4-Trichlorobenzene 120-82-1 10 625

1,1,1-Trichloroethane 71-55-6 10 624 1,1,2-Trichloroethane 79-00-5 10 624

Trichloroethene 79-01-6 10 624 [Trichloroethylene] Trichlorofon 52-68-6 0.45 1657

2,4,5-Trichlorophenol 95-95-4 50 1625 3 2,4,6-Trichlorophenol 88-06-2 10 625 Triethanolmine dodecylbenzenesulfonate 27323-41-7 Not Specified 12 TBD 12 Triethylamine 121-44-8 50 mg/L 1667

TTHM (Total Trihalomethanes) 624 Bromodichloromethane 75-27-4 10 Dibromochloromethane 124-48-1 10 Tribromomethane [Bromoform] 75-25-2 10 Trichloromethane [Chloroform] 67-66-3 10 Trimethylamine 75-50-3 Not Specified 12 1666 13

Uranium, total 7440-61-1 0.5 200.8 4 Vanadium, total 7440-62-2 5 200.8 4 Vinyl acetate 108-05-4 50 1624 3 Vinyl chloride 75-01-4 10 624 Xylenes, total 1330-20-7 10 1624C 3 Xylenol 1300-71-6 30 625 Zinc, total 7440-66-6 5.0 200.8 4 Zirconium 7440-67-7 100 1620

1 Chemical Abstracts Service Registry Number. 2 Screening levels are noted for toxic pollutants that (1) do not have numerical criteria in the Standards and (2) are of potential concern only at concentrations substantially higher than the MAL. 3 EPA Methods 624 and 625 may be utilized in lieu of Methods 1624 and 1625, respectively, as provided in the protocol for Transfer of an Analyte Between Methods as described in Analytical Method Guidance for the Pharmaceutical Manufacturing Point Source Category, U. S. Environmental Protection Agency, EPA 821-B-00- 003, August 1999. See Appendix G.

4 EPA Methods 200.8 and 200.9 are approved for use in the NPDES program (40 CFR Part 136, revised March 12, 2007). 5 40 CFR Part 136, Table IC refers to the Methods for Benzene: Chlorinated Organic Compounds, Pentachlorophenol and Pesticides in Water and Wastewater, U.S. Environmental Protection Agency, September 1978. However, no analytical method number is specified in 40 CFR Part 136. 6 Hydrolyzes in water. Will not require applicant to analyze at this time. 7 Trivalent chromium (Cr) determined by subtracting hexavalent Cr from total Cr. 8 EPA procedure not approved. Will not require applicant to analyze at this time. 9 Either method listed for mercury may be used.

10 Although EPA Methods 245.1 Revision 3.0 and 245.2 are included as approved analytical methods for mercury in the 40 CFR Part 136 (Federal Register/ Vol. 72, No. 47/ Monday, March 12, 2007/ Rules and Regulations, page 11220), the Director of the EPA Office of Wastewater Management published a policy memo, dated August 23, 2007, clarifying and explaining that based on the existing regulatory requirements for NPDES permitting, only the most sensitive analytical methods for mercury, such as EPA Methods 1631E and 245.7, are appropriate in most instances for use in deciding whether to set a permit limit for mercury and for sampling and analysis of mercury pursuant to monitoring requirements within a permit. 11 Pollutant analyzed by the EPA as published in the Centralized Waste Treatment Final Development Document, Chapter 7, and Federal Register Vol. 65, No. 247, Friday, December 22, 2000, pp. 81295-81300, using Method 625. 12 The TCEQ has requested the EPA to provide MALs and/or suggested methods. 13 Method is draft and has not yet been approved by EPA. 14 The MAL is 3.3 times the MDL and lowest calibration point for Captan of 0.1 μg/L as given in Method 1656. 15 Methods for Benzene: Chlorinated Organic Compounds, Pentachlorophenol and Pesticides in Water And Wastewater. U.S. Environmental Protection Agency, September 1978, 16 Selected Analytical Methods Approved and Cited by the USEPA. Supplement to the Fifteenth Edition of Standard Methods for the Examination of Water and Wastewater, 1981. 17 EPA Methods 605, 607, and 612 may also be used. 18 Except as provided in 40 CFR Part 136.5, pesticide manufacturers must determine the discharge parameter values required under the Clean Water Act by one of the methods described in Table 1G of 40 CFR Part 136.3(a). See 40 CFR Part 455.50. 19 Method 1668B is not currently listed as an approved method at 40 CFR Part 136.

Table E-2. Analytical Methods and MALs for the Determination of Pollutants Regulated by § 307.6 of the Standards

Notes on table:

1) Suggested analytical methods have traditionally been EPA-approved analytical methods either in the 40 CFR Part 136, as amended, or in EPA-published documents pertaining to wastewater matrices, or methods developed and published by the TCEQ or other government agencies for wastewater. Applicants and permittees may use any analytical method approved in 40 CFR Part 136 that is sufficiently sensitive to demonstrate compliance with their numeric permit limits (mass and concentration).

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Acrylonitrile 1624B 50 50 The MAL is based on the MDL published in 40 CFR Part 136, Method 1624B. The MAL is equal to the minimum level at which the analytical system shall give acceptable calibration points documented in 40 CFR Part 136, Method 1624B. Aldrin 608 0.01 0.004 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MAL is 2.5 times the MDL documented in 40 CFR Part 136, Method 608. Aluminum, total 200.8 2.5 1.0 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MAL is 2.5 times the MDL based on EPA Method 200.8.1 Anthracene 625 10 —4 The MAL is based on the MQL developed by EPA Region 6, July 1992. Antimony, total 200.8 5 0.4 The MAL is 12.5 times the MDL based on EPA Method 200.8.1 Arsenic, total 200.8 0.5 0.4 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is published in EPA Method 200.8.1 Barium, total 200.8 3 0.8 The MAL is approximately 3.8 times the MDL based on EPA Method 200.8.1

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Benzene 624 10 4.4 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Benzidine 625 50 44 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 625. Benzo(a)anthracene 625 5 —11 The MAL is based on the CERCLA National Contract Laboratory Program’s CRQL referred to by EPA Region 6 MQL guidance dated February 8, 2008. Benzo(a)pyrene 625 5 2.5 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 625. Bis(2-chloroethyl)ether 625 10 5.7 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 625. Bis(chloromethyl)ether —4 —4 —4 Analytical method undetermined. Bis(2-ethylhexyl)phthalate 625 10 2.5 The MAL is based on [Di(2-ethylhexyl)phthalate] the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 625. Bromodichloromethane 624 10 2.2 The MAL is based on [Dichlorobromomethane] the MQL developed by EPA Region6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Cadmium, total 200.8 1 0.5 The MAL is two times the MDL based on EPA Method 200.8.1 Carbaryl 632 5.0 0.02 The MAL is based on laboratory consensus taken October 1992. The MDL is given by EPA Method 632.6

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Carbon tetrachloride 624 2 —11 The MAL is four times the CERCLA National Contract Laboratory Program’s CRQL of 0.5 μg/L referred to by EPA Region 6 MQL guidance dated February 8, 2008. Chlordane 608 0.2 0.014 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 608. Chlorine 4500-Cl E 33 10 The MAL is based on 4500-Cl G the MQL developed by EPA Region 6, February 8, 2008. The MDL is documented in SM 4500-Cl E and 4500-Cl G. Chlorobenzene 624 10 6.0 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Chlorodibromomethane 624 10 3.1 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Chloroform 624 10 1.6 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Chlorpyrifos 1657 0.05 0.004 The MAL is 12.5 times the MDL given by EPA, Method 1657.6 Chromium, total 200.8 3 0.9 The MAL is 3.3 times the MDL based on EPA Method 200.8.1 Chromium, hexavalent 218.6, 3.0 0.3 The MAL is ten times Rev. 3.3 the MDL given by EPA Method 218.6, Revision 3.3.3

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Chromium, trivalent See — — Trivalent chromium is documen- determined by tation subtracting the note. concentration of hexavalent chromium (dissolved) from the dissolved total chromium concentration. Chrysene 625 5 2.5 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 625. Copper, total 200.8 2 0.5 The MAL is 3.3 times the MDL from Method 200.8 rounded m-cresol 625 10 3 The MDL is documented in 40 CFR Part 136, Method 625.2, 15

o-cresol 625 10 4.7 The MDL is documented in 40 CFR Part 136, Method 625.2, 15

p-Cresol 625 10 7.8 The MDL is [4-Methylphenol] documented in 40 CFR Part 136, Method 625.2, 15

Cyanide, total 335.4, 10 —4 The MAL is based on 4500-CN the MQL approved by D, EPA Region 6 on 4500-CN February 8, 2008. E,

Cyanide, available 16 4500-CN 10 —5 The MAL is based on G the MQL approved by EPA Region 6 on February 8, 2008.There is no MDL documented in Standard Methods (20th Edition).5 OIA-1677 2 0.5 The MAL and MDL are documented in EPA Method OIA-1677 dated August 1999.

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation 4,4’-DDD 608 0.1 0.011 The MAL is approximately 9.1 times the detection limit documented in 40 CFR Part 136, Method 608. The MAL is based on the MQL developed by EPA Region 6, July 1992. 4,4’-DDE 608 0.1 0.004 The MAL is based on the MQL Developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 608. 4,4’-DDT 608 0.02 0.012 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 608. 2,4-D 615 or 0.7 0.07 The MAL is ten times SM6640B the detection limit given by SM6640B.5 Danitol No —4 —4 No published EPA [Fenpropathrin] published method available. EPA method available Demeton 1657 12, 13 0.20 0.020 The MAL is ten times the detection limit given by EPA Method 1657.6 Diazinon 1657 0.5 0.038 The MAL is approximately 13.2 times the detection limit given by EPA Method 1657.6 614 0.1 0.01 The MAL is 10 times the detection limit given by EPA Method 614.6 Dibenzo(a,h)anthracene 625 5 —4 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. 1,2-Dibromoethane 1624 10 —4 The MAL is based on the baseline value documented in Attachment 15-1, page 5-17 of the EPA Development Document for Effluent Limitations Guidelines and Standards for the Centralized Waste Treatment Industry - Final, August 2000.

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation m-Dichlorobenzene 624 10 1.9 The MAL is based on [1,3-Dichlorobenzene] the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. o-Dichlorobenzene 624 10 1.9 The MAL is based on [1,2-Dichlorobenzene] the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. p-Dichlorobenzene 624 10 4.4 The MAL is based on [1,4-Dichlorobenzene] the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. 3,3'-Dichlorobenzidine 625 5 —11 The MAL is based on the CERCLA National Contract Laboratory Program’s CRQL referred to by EPA Region 6 MQL guidance dated February 8, 2008. 1,2-Dichloroethane 624 10 2.8 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. 1,1-Dichloroethene 624 10 2.8 The MAL is based on [1,1-Dichloroethylene] the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Dichloromethane 624 20 2.8 The MAL is based on [Methylene choride] the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. 1,2-Dichloropropane 624 10 6.0 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. 1,3-Dichloropropene 624 10 5.0 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624 for cis-1,3- Dichloropropene.

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Dicofol ASTM 1 —4 The MAL is 3.3 times [Kelthane] D5812- the lowest calibration 96(02) point for Dicofol of 0.3 μg/L given in Method 1656. Dieldrin 608 0.02 0.002 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 608. 2,4-Dimethylphenol 625 10 2.7 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 625. Di-n-butyl phthalate 625 10 —4 The MAL is based on the MQL developed by EPA Region 6, July 1992. Dioxins/Furans (TCDD 1613B (ppq) (ppq) The MAL is based on Equivalents) the Minimum Level 2,3,7,8-TCDD 10 See documentation note (ML) published in 40 1,2,3,7,8-PeCDD 50 CFR Part 136, Method 2,3,7,8-HxCDDs 1613B. The ML for 1,2,3,4,7,8- 50 each analyte is defined HxCDD 50 as the level at which the 1,2,3,6,7,8- 50 entire analytical system HxCDD 50 must give a 1,2,3,7,8,9- 100 recognizable signal and HxCDD 10 acceptable calibration 1,2,3,4,6,7,8-HpCDD 50 point. It is equivalent to OCDD 50 the concentration of the 2,3,7,8-TCDF lowest calibration 1,2,3,7,8-PeCDF10 50 standard, assuming that 2,3,4,7,8-PeCDF 50 all method-specified 2,3,7,8-HxCDFs 50 sample weights, 1,2,3,4,7,8- 50 volumes, and cleanup HxCDF procedures have been 1,2,3,6,7,8- 50 employed. HxCDF 50 1,2,3,7,8,9- 100 HxCDF 2,3,4,6,7,8- HxCDF 2,3,4,7,8-HpCDFs 1,2,3,4,6,7,8- HpCDF 1,2,3,4,7,8,9- HpCDF OCDF Diuron 632 0.09 0.009 The MAL is ten times the detection limit given by EPA Method 632.6

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Endosulfan I (alpha) 608 0.01 —11 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 608. Endosulfan II (beta) 608 0.02 0.004 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 608. Endosulfan sulfate 608 0.1 0.066 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 608. Endrin 608 0.02 0.006 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 608. Ethylbenzene 624 10 7.2 The MAL is based on the MQL developed by EPA Region 6 July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Fluoride 300.0 or 500 50 The MAL is ten times 300.1 the lowest concentration of the applicable working range given by EPA Method 300.0. Guthion 1657 0.1 0.009 The MAL is 11.1 times [Azinphos Methyl] the detection limit given by EPA Method 1657.6 Heptachlor 608 0.01 0.003 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MAL is 3.3 times the detection limit documented in 40 CFR Part 136, Method 608. Heptachlor epoxide 608 0.01 —11 The MAL is based on the CERCLA National Contract Laboratory Program’s CRQL referred to by EPA Region 6 MQL guidance dated February 8, 2008.

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Hexachlorobenzene 625 5 1.9 The MAL is based on the CERCLA National Contract Laboratory Program’s CRQL referred to by EPA Region 6 MQL guidance dated February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 625. Hexachlorobutadiene 625 10 0.9 The MAL is 11.1 times the detection limit documented in 40 CFR Part 136, Method 625 and corresponds to the MQL developed by EPA Region 6, July 1992. Alpha- 608 0.05 0.003 The MAL is 16.7 times Hexachlorocyclohexane the detection limit documented in 40 CFR Part 136, Method 608. The MAL is based on the MQL developed by EPA Region 6, July 1992. Beta- 608 0.05 0.006 The MAL is 8.3 times Hexachlorocyclohexane the detection limit documented in 40 CFR Part 136, Method 608. The MAL is based on the MQL developed by EPA Region 6, July 1992. Gamma- 608 0.05 0.004 The MAL is 12.5 times Hexachlorocyclohexane the detection limit [Lindane] documented in 40 CFR Part 136, Method 608. The MAL is based on the MQL developed by EPA Region 6, July 1992. Hexachlorocyclopentadiene 625 or 10 —4 The MAL is based on 1625B 14 the MQL developed by EPA Region 6, July 1992. Hexachloroethane 625 20 1.6 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 625. Hexachlorophene 604.1 10 1.2 The MAL is 8.3 times the detection limit given in EPA Method 604.1.6

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Lead, total 200.8 0.5 0.05 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is published in EPA Method 200.8.1 Malathion 1657 or 0.1 0.011 The MAL is 9.1 times SM6630C the detection limit given in EPA Method 1657.6 Mercury7, 8, 9 245.7, 0.005 0.0018 The MAL is based on Rev. 2.0 the MQL published in the EPA national policy memorandum dated August 23, 2007 and in the Method 245.7 published in February 2005. Mercury7, 8, 9 1631E 0.0005 0.0002 The MAL is based on the MQL published in the EPA national policy memorandum dated August 23, 2007 and in the Method 1631E published in August 2002. Methoxychlor 617 or 2 0.176 The MAL is 11.4 times SM6630B the detection limit given and C in EPA Method 617.6 Methyl ethyl ketone 624 50 50 The MAL is the minimum level at which the analytical system shall give acceptable calibration points documented in 40 CFR 136, Method 1624. MAL is five times the CRQL for water analysis using Method 624 from the EPA Region 6, Target Compound List acquired January 14, 1993. Mirex SM6630B 0.02 0.004 The MAL is 3.75 times and C the MDL and lowest calibration point for Mirex of 0.004 μg/L as given in Method 1656. Nickel, total 200.8 2 0.5 The MAL is less than or equal to 3.3 times the MDL for EPA Method 200.8 1 rounded. Nitrate-nitrogen 300.1 100 10 The MAL is ten times the lowest concentration of the applicable range given by EPA Method 300.1, Rev. 1.0.

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Nitrobenzene 625 10 1.9 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 625. N-Nitrosodiethylamine 625 20 5 The suggested method, MAL and MDL are based on laboratory consensus taken October 1992. N-Nitroso-di-n-butylamine 625 20 5 The suggested method, MAL and MDL are based on laboratory consensus taken October 1992. para-Nonylphenol 1625 333 111 The MAL is three times (CASRN 84852-15-3) the MDL published in Method 1625. Nonylphenol 1625 333 111 The MAL is three times (CASRN 25154-52-3) the MDL published in Method 1625. Parathion (ethyl) 1657 or 0.1 0.010 The MAL is ten times SM6630C the detection limit given in EPA Method 1657.6 Pentachlorobenzene 625 20 5 The suggested method, MAL and MDL are based on laboratory consensus taken October 1992. Pentachlorophenol 625 5 3.6 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. Phenanthrene 625 10 5.4 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 625. Polychlorinated biphenyls (PCBs) PCB-77 1668B 0.0005 0.000169 The MALs are based on PCB-81 1668B 0.0005 0.000177 estimated minimum PCB-126 1668B 0.0005 0.000136 levels as published in PCB-169 1668B 0.0005 0.000161 Method 1668B. PCB-1016 608 0.2 ND4 PCB-1221 608 0.2 ND4 The MALs are based on PCB-1232 608 0.2 ND4 the MQLs approved by PCB-1242 608 0.2 0.065 EPA Region 6 on PCB-1248 608 0.2 ND4 February 8, 2008. The PCB-1254 608 0.2 ND4 MDL is documented in PCB-1260 608 0.2 ND4 40 CFR Part 136, Method 608.

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Pyridine 625 2 20 10 The MAL is two times the MDL published in the List of Lists: A Catalog of Analytes and Methods, U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Industrial Technology Division, September 1990. Selenium, total 200.8 5 2.1 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MDL is published in EPA Method 200.8.1 Silver, total 200.8 1 0.1 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MAL is five times the MDL in EPA Method 200.8.1 1,2,4,5-Tetrachlorobenzene 1625 20 10 The MAL is 2 times the MDL published in the List of Lists: A Catalog of Analytes and Methods, U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Industrial Technology Division, September 1990. 1,1,2,2-Tetrachloroethane 624 10 6.9 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Tetrachloroethene 624 10 4.1 The MAL is based on [Tetrachloroethylene] the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Thallium, total 200.8 1 0.3 The MAL is based on the MQL approved by EPA Region 6 on February 8, 2008. The MAL is approximately 1.7 times the MDL in EPA Method 200.8.1

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation Toluene 624 10 6.0 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624.

Toxaphene 608 1 0.24 The MAL is based on the MQL approved by EPA Region 6 in February 8, 2008. The MDL is documented in 40 CFR Part 136, Method 608. 2,4,5-TP SM6640B 0.3 0.03 The MAL is ten times [Silvex] the detection limit given by SM6640B.5 Tributyltin TNRCC 0.01 3.2 × 10-3 The method is entitled [TBT] 1001 “Measurement of Butyltin Species in Water by n-Pentyl Derivatization with Gas Chromatography/Flame Photometric Detection (GC/FPD) and Gas Chromatography/Mass Spectrometry (GC/MS).” The MAL is equal to EPA tributyltin advisory level. 1,1,1-Trichloroethane 624 10 3.8 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. 1,1,2-Trichloroethane 624 10 5.0 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. Trichloroethene 624 10 1.9 The MAL is based on [Trichloroethylene] the MQL developed by EPA Region 6, July 1992. The MDL is documented in 40 CFR Part 136, Method 624. 2,4,5-Trichlorophenol 1625 50 10 The MAL is five times the minimum level at which the analytical system shall give acceptable calibration points documented in 40 CFR Part 136, Method 1625.

Suggested MAL MDL MAL Source Pollutant Method (μg/L) (μg/L) Documentation TTHM (Total 624 The MAL is based on Trihalomethanes) 10 2.2 the CRQL for water Bromodichloromethane 10 3.1 analysis using Method Dibromochloromethane 10 4.7 624 from the EPA Tribromomethane 10 1.6 Region 6, Target [Bromoform] Compound List Trichloromethane acquired January 14, [Chloroform] 1993. Method detection limits are documented in 40 CFR Part 136, Method 624. Vinyl chloride 624 10 —4 The MAL is based on the MQL developed by EPA Region 6, July 1992. The MDL is given as “nd” in 40 CFR Part 136, Method 624. Zinc, total 200.8 5 1.8 The MAL is approximately 2.8 times the MDL based on EPA Method 200.8.1

1 Method 200.8 is approved for use in the NPDES program [40 CFR Part 136, revised March 12, 2007]. Method 200.8. Determination of Trace Elements in Waters and Wastes by Inductively Coupled-Plasma - Mass Spectrometry, U.S. Environmental Protection Agency, EPA 600-R-94-111, May 1994. Method 200.8 contains accuracy and precision data generated using determination of trace elements in waters and wastes by inductively coupled plasma-mass spectrometry techniques for the following metals: aluminum, arsenic, barium, cadmium, chromium, copper, lead, nickel, selenium, silver, thallium, and zinc. 2 Pollutant analyzed by the EPA as published in the Centralized Waste Treatment Final Development Document, Chapter 7, and Federal Register Vol. 65, No. 247, Friday, December 22, 2000, pp. 81295-81300, using Method 625. 3 Methods for the Chemical Analysis of Water and Wastes, U.S. Environmental Protection Agency, Environmental Monitoring Systems Laboratory-Cincinnati (EMSL-Cl), EPA-600/4-79-020, Revised March 1983 and 1979 where applicable. 4 Not determined or not published by the EPA. 5 Standard Methods Online, American Public Health Association, American Water Works Association, and Water Environment Federation, 2005. URL: http://www.standardmethods.org/applications/Login/index.cfm?test=no&forwardto= 6 EPA Methods for the Determination of Nonconventional Pesticides in Municipal and Industrial Wastewater, U.S. Environmental Protection Agency, EPA-821-R-93-010-A & B, August 1993. 7 Either method listed for mercury may be used. 8 Method 1631, Revision E. Mercury in Water by Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence Spectrometry, U.S. Environmental Protection Agency, Office of Water, EPA 821-R-02-019, August 2002. 9 Although EPA Methods 245.1 Revision 3.0 and 245.2 are included as approved analytical methods for mercury in the 40 CFR Part 136 (Federal Register/ Vol. 72, No. 47/ Monday, March 12, 2007/ Rules and Regulations, page 11220), the Director of the EPA Office of Wastewater Management published a policy memo, dated August 23, 2007, clarifying and explaining that based on the existing regulatory requirements for NPDES permitting, only the most sensitive analytical methods for mercury, such as EPA Methods 1631E and 245.7, are appropriate in most instances for use in deciding whether to set a permit limit for mercury and for sampling and analysis of mercury pursuant to monitoring requirements within a permit.

10 The ML is not published in 40 CFR Part 136, Method 1613B. 11 The MDL is published in 40 CFR Part 136. 12 Methods for Benzene: Chlorinated Organic Compounds, Pentachlorophenol and Pesticides in Water And Wastewater. U.S. Environmental Protection Agency, September 1978, 13 Selected Analytical Methods Approved and Cited by the USEPA. Supplement to the Fifteenth Edition of Standard Methods for the Examination of Water and Wastewater, 1981. 14 EPA Methods 605, 607, and 612 may also be used. 15 Product and Product Group Discharges Subject to Effluent Limitations and Standards for the Organic Chemicals, Plastics, and Synthetic Fibers Point Source Category – 40 CFR Part 414, U.S. Environmental Protection Agency, Office of Water. April 2005.

16 The EPA has published Method OIA-1677 for the analysis of available cyanide as a method that tends to overcome matrix interferences present with other methods and includes a lower MAL. Permit writers may determine the appropriate method for permittees on a case-by-case basis in situations where a lower MAL is needed for permit compliance or for eliminating interferences and matrix problems.

Appendix F. Nutrient Screening Parameters for Certain Reservoirs.

Table F-1: Total Phosphorus and Chlorophyll a Means for Certain Reservoirs Notes on table: 1) Segment numbers in parentheses refer to the segment in whose watershed the lake is located.

2) Data used to calculate the TP, chlorophyll a, and secchi depth means were collected at the SWQM monitoring site(s) listed in the Site ID column for each reservoir.

3) The mean values for TP, chlorophyll a, and secchi depth are arithmetic means. The means are calculated from the same data sets used to calculate TP and transparency screening levels and chlorophyll a criteria in the Standards.

Seg- TP Chlorophyll Secchi ment Lake/Reservoir Name Site ID Mean a Mean Mean No. (mg/L) (μg/L) (m) (0100) Palo Duro Reservoir 10005 0.171 12.95 0.40 0102 Lake Meredith 10036 0.022 3.10 1.98 0208 Lake Crook 10137 0.165 4.77 0.23 0209 Pat Mayse Lake 10138 0.029 7.64 1.34 Farmers Creek Reservoir 0210 10139 0.026 4.06 1.18 (also known as Lake Nocona) 0212 Lake Arrowhead 10142 0.130 6.99 0.69 0213 Lake Kickapoo 10143 0.066 3.81 0.35 0215 Diversion Lake 10157 0.026 6.21 0.96 0217 Lake Kemp 10159 0.023 5.78 1.33 0223 Greenbelt Lake 10173 0.022 3.14 2.03 0228 Mackenzie Reservoir 10188 0.021 3.74 1.37 0229 Lake Tanglewood 10192 1.022 24.75 0.70 0302 Wright Patman Lake 10213 0.087 12.46 0.64 0403 Lake O' the Pines 10296 0.027 9.31 1.17 0405 Lake Cypress Springs 10312 0.027 11.21 1.28 0507 Lake Tawakoni 10434 0.045 23.95 1.00 0509 Murvaul Lake 10444 0.057 37.46 0.61 0510 Lake Cherokee 10445 0.019 5.69 1.41 0512 Lake Fork Reservoir 10458 0.036 9.78 1.59 0603 B. A. Steinhagen Lake 10582 0.068 8.04 0.43 0605 Lake Palestine 16159 0.027 17.37 0.90 0610 Sam Rayburn Reservoir 14906 0.028 4.52 1.97 0613 Lake Tyler 10637 0.026 8.27 1.16 0613 Lake Tyler East 10638 0.027 7.00 1.16 0614 Lake Jacksonville 10639 0.026 4.05 1.63

Seg- TP Chlorophyll Secchi ment Lake/Reservoir Name Site ID Mean a Mean Mean No. (mg/L) (μg/L) (m) 0803 Lake Livingston 10899 0.136 15.15 0.79 0807 Lake Worth 10942 0.073 23.51 0.79 10944 0809 Eagle Mountain Reservoir 0.062 17.25 0.92 10945 0811 Bridgeport Reservoir 10970 0.045 3.73 1.23 0813 Houston County Lake 10973 0.026 7.35 1.43 0815 Bardwell Reservoir 10979 0.043 15.05 0.64 0816 Lake Waxahachie 10980 0.027 11.84 0.78 0817 Navarro Mills Lake 10981 0.062 9.74 0.45 10982 0818 Cedar Creek Reservoir 0.067 21.88 0.86 16749 0823 Lewisville Lake 11027 0.046 11.67 0.76 11035 0826 Grapevine Lake 0.063 7.21 1.01 16113 0827 White Rock Lake 11038 0.086 20.89 0.51 11040 0828 Lake Arlington 0.033 15.99 0.86 13904 11046 0830 Benbrook Lake 0.057 18.01 0.84 15151 0832 Lake Weatherford 11061 0.045 8.31 0.70 0834 Lake Amon G. Carter 11063 0.030 3.91 1.45 0836 Richland-Chambers Reservoir 15168 0.031 10.58 1.27 1002 Lake Houston 11204 0.165 7.18 0.34 1012 Lake Conroe 11342 0.042 16.05 0.94 1203 Whitney Lake 11851 0.027 11.21 1.49 1205 Lake Granbury 11860 0.054 15.53 1.14 1207 Possum Kingdom Lake 11865 0.041 6.84 2.64 (1208) Millers Creek Reservoir 11679 0.062 10.34 0.31 1212 Somerville Lake 11881 0.082 35.16 0.68 1216 Stillhouse Hollow Lake 11894 0.029 1.71 3.22 1220 Belton Lake 11921 0.028 4.11 2.05 1222 Proctor Lake 11935 0.079 18.48 0.60 1224 Leon Reservoir 11939 0.023 6.17 1.22 1225 Waco Lake 11942 0.068 16.11 0.88 1228 Lake Pat Cleburne 11974 0.059 11.93 0.56 1230 Lake Palo Pinto 11977 0.050 3.81 0.69 1231 Lake Graham 11979 0.039 4.37 0.73

Seg- TP Chlorophyll Secchi ment Lake/Reservoir Name Site ID Mean a Mean Mean No. (mg/L) (μg/L) (m) 1233 Hubbard Creek Reservoir 12002 0.030 3.68 1.34 1234 Lake Cisco 12005 0.017 3.07 1.58 1235 Lake Stamford 12006 0.056 11.02 0.47 1236 Fort Phantom Hill Reservoir 12010 0.044 6.12 0.59 1237 Lake Sweetwater 12021 0.033 8.49 0.88 1240 White River Lake 12027 0.046 8.02 0.54 (1241) Buffalo Springs Lake 11529 0.081 38.20 0.65 1247 Granger Lake 12095 0.044 7.43 0.47 1249 Lake Georgetown 12111 0.032 2.61 2.15 1252 Lake Limestone 12123 0.065 13.08 0.83 1254 Aquilla Reservoir 12127 0.037 8.73 0.69 1403 Lake Austin 12294 0.023 2.45 2.12 1404 Lake Travis 12302 0.021 2.46 3.68 1405 Marble Falls Lake 12319 0.023 6.87 1.44 1406 Lake Lyndon B. Johnson 12324 0.022 6.72 1.44 1407 Inks Lake 12336 0.026 9.66 1.62 1408 Lake Buchanan 12344 0.022 6.41 1.97 1411 E. V. Spence Reservoir 12359 0.022 8.97 1.27 (1412) Lake Colorado City 12167 0.039 10.11 0.77 (1416) Brady Reservoir 12179 0.030 17.02 0.69 1418 Lake Brownwood 12395 0.019 3.49 1.24 1419 Lake Coleman 12398 0.018 4.02 1.29 1422 Lake Nasworthy 12418 0.045 11.12 0.52 1423 Twin Buttes Reservoir 12422 0.066 8.81 0.87 1425 O.C. Fisher Lake 12429 0.112 23.60 0.36 (1426) Oak Creek Reservoir 12180 0.025 4.62 0.78 1429 Lady Bird Lake (formerly Town Lake) 12476 0.031 4.51 1.94 1433 O. H. Ivie Reservoir 12511 0.024 4.14 2.11 1805 Canyon Lake 12598 0.025 2.64 2.72 1904 Medina Lake 12826 0.011 1.86 2.84 2103 Lake Corpus Christi 12967 0.148 10.08 0.49 2116 Choke Canyon Reservoir 13019 0.044 7.77 1.16 2303 International Falcon Reservoir 13189 0.047 9.56 0.79 2305 International Amistad Reservoir 13211 0.015 1.44 3.55

Seg- TP Chlorophyll Secchi ment Lake/Reservoir Name Site ID Mean a Mean Mean No. (mg/L) (μg/L) (m) 2312 Red Bluff Reservoir 13267 0.030 14.81 0.85 (2454) Cox Creek Lake 12514 0.268 8.10 0.16

Table F-2: Size Characteristics and Retention Times for Certain Reservoirs Notes on table: 1) Segment numbers in parentheses refer to the segment in whose watershed the lake is located.

2) Surface areas are at normal pool elevation as defined in Appendix C of the Standards. Surface areas were obtained from the Texas Water Development Board unless noted otherwise.

3) Volumes are at normal pool elevation as defined in Appendix C of the Standards. Volumes include the dead pool and were obtained from the Texas Water Development Board (TWDB) unless noted otherwise.

4) The volumetric survey year is the year in which the actual survey was performed (not the report year).

5) Retention times are calculated as noted in the source documentation but may be recalculated as reservoir capacities or flows are updated or as the TCEQ becomes aware of significant water transfers in or out of these reservoirs.

Surface Volumetric Retention Retention Segment Volume Lake/Reservoir Name Area Survey Time Time No. (acre-ft.) (acres) Year (yrs) Source* (0100) Palo Duro Reservoir 2,397 61,239 1986 ― ― 0102 Lake Meredith 16,411 817,970 1995 15.1 Ground 0208 Lake Crook 1,060 9,210 2003 0.22 Ground 0209 Pat Mayse Lake 5,940 118,100 2008 1.3 Ground Farmers Creek Reservoir 0210 1,362 21,749 2001 3.0 Ground (also known as Lake Nocona) 0212 Lake Arrowhead 14,969 235,997 2001 4.7 TCEQ 0213 Lake Kickapoo 6,028 85,825 2001 2.2 TCEQ 0215 Diversion Lake 3,133 33,420 1958 0.36 TCEQ 0217 Lake Kemp 15,357 245,434 2006 3.0 Ground 0223 Greenbelt Lake 2,025 60,400 ― 6.4 Ground 0228 Mackenzie Reservoir 896 46,454 1973 38.1 Ground (a) 0229 Lake Tanglewood 258 ― ― ― ― 0302 Wright Patman Lake 24,438 167,300 1997 0.06 Ground 0403 Lake O' the Pines 16,919 241,081 1998 0.56 Ground 0405 Lake Cypress Springs 3,461 67,690 2007 1.7 Ground 0507 Lake Tawakoni 37,879 888,140 1997 2.5 Ground 0509 Murvaul Lake 3,529 38,284 1998 0.85 Ground 0510 Lake Cherokee 3,467 43,737 2003 0.68 Ground 0512 Lake Fork Reservoir 27,264 636,133 2001 3.9 Ground 0603 B. A. Steinhagen Lake 10,687 66,972 2003 0.03 Ground 0605 Lake Palestine 22,656 373,202 2003 1.2 Ground 0610 Sam Rayburn Reservoir 112,590 2,876,033 2004 1.8 Ground

Surface Volumetric Retention Retention Segment Volume Lake/Reservoir Name Area Survey Time Time No. (acre-ft.) (acres) Year (yrs) Source* 0613 Lake Tyler 2,341 (b) 43,500 (c) 2003 ― ― (b) (d) 0613 Lake Tyler East 2,396 36,698 2003 0.84 Ground 0614 Lake Jacksonville 1,165 25,732 2006 1.8 Ground 0803 Lake Livingston 83,277 1,741,867 1991 0.35 Ground 0807 Lake Worth 3,458 33,495 2001 ― ― 0809 Eagle Mountain Reservoir 8,702 182,505 2008 0.95 Ground 0811 Bridgeport Reservoir 11,954 366,236 2000 3.1 Ground 0813 Houston County Lake 1,330 17,665 1999 1.3 Ground 0815 Bardwell Reservoir 3,138 46,472 1999 1.0 Ground 0816 Lake Waxahachie 656 11,386 2000 ― ― 0817 Navarro Mills Lake 4,736 49,827 2008 0.64 Ground 0818 Cedar Creek Reservoir 32,873 644,785 2005 1.7 Ground 0823 Lewisville Lake 29,170 571,926 2007 0.99 Ground 0826 Grapevine Lake 6,893 164,703 2002 1.5 Ground 0827 White Rock Lake 1,088 9,004 1993 ― ― 0828 Lake Arlington 1,926 40,188 2007 2.4 Ground 0830 Benbrook Lake 3,635 85,648 1998 1.7 Ground 0832 Lake Weatherford 1,112 17,812 2008 1.3 TCEQ 0834 Lake Amon G. Carter 1,540 20,050 ― ― ― Richland-Chambers 0836 41,356 1,136,600 2007 1.8 TCEQ Reservoir 1002 Lake Houston 11,854 133,990 1994 0.11 Ground 1012 Lake Conroe 20,118 416,228 1996 2.7 Ground 1203 Whitney Lake 23,220 554,203 2005 0.61 Ground 1205 Lake Granbury 7,945 129,011 2003 0.21 Ground 1207 Possum Kingdom Lake 16,716 540,340 2005 1.1 Ground (1208) Millers Creek Reservoir 2,268 29,171 1993 ― ― 1212 Somerville Lake 11,555 147,104 2003 0.65 TCEQ 1216 Stillhouse Hollow Lake 6,484 227,825 2005 1.5 Ground 1220 Belton Lake 12,135 435,225 2003 1.3 Ground 1222 Proctor Lake 4,537 55,457 2002 0.86 Ground 1224 Leon Reservoir 1,590 27,290 ― 1.2 Ground 1225 Waco Lake 7,913 199,405 1995 0.73 Ground 1228 Lake Pat Cleburne 1,558 25,730 2008 ― ― 1230 Lake Palo Pinto 2,498 27,650 2007 0.98 Ground

Surface Volumetric Retention Retention Segment Volume Lake/Reservoir Name Area Survey Time Time No. (acre-ft.) (acres) Year (yrs) Source* 1231 Lake Graham 2,444 45,302 1998 1.9 Ground 1233 Hubbard Creek Reservoir 14,922 324,983 1997 4.1 Ground 1234 Lake Cisco 10,450 26,000 ― ― ― 1235 Lake Stamford 5,124 51,573 1999 ― ― 1236 Fort Phantom Hill Reservoir 4,213 70,036 1993 ― ― 1237 Lake Sweetwater 630 11,900 ― 3.8 Ground 1240 White River Lake 2,020 44,300 1993 16.3 Ground (1241) Buffalo Springs Lake 200 4,200 ― ― ― 1247 Granger Lake 4,064 52,525 2002 0.42 Ground 1249 Lake Georgetown 1,287 36,904 2005 0.76 Ground 1252 Lake Limestone 12,553 208,017 2002 0.93 Ground 1254 Aquilla Reservoir 3,066 44,566 2008 1.3 Ground 1403 Lake Austin 1,599 21,804 1999 0.02 Ground 1404 Lake Travis 19,199 1,134,863 2008 1.1 Ground 1405 Marble Falls Lake 608 7,486 2007 0.01 Ground 1406 Lake Lyndon B. Johnson 6,273 133,090 2007 0.14 Ground 1407 Inks Lake 788 14,074 2007 0.02 Ground 1408 Lake Buchanan 22,019 875,610 2006 1.2 Ground 1411 E. V. Spence Reservoir 14,640 517,272 1999 33.3 Ground (1412) Lake Colorado City 1,612 31,805 ― 1.3 Ground (1416) Brady Reservoir 2,020 30,430 ― 2.3 Ground 1418 Lake Brownwood 6,587 131,429 1997 1.2 Ground 1419 Lake Coleman 1,811 38,094 2006 2.1 Ground 1422 Lake Nasworthy 1,380 10,108 1993 1.2 Ground 1423 Twin Buttes Reservoir 9,080 186,200 ― 18.7 Ground 1425 O. C. Fisher Lake 5,440 115,743 ― 6.2 Ground (1426) Oak Creek Reservoir 2,375 39,360 ― 2.1 Ground Lady Bird Lake 1429 468 6,409 1999 0.01 Ground (formerly Town Lake) 1433 O. H. Ivie Reservoir 19,149 554,340 ― 11.9 Ground 1805 Canyon Lake 8,308 378,852 2000 1.3 Ground 1904 Medina Lake 6,066 254,823 1995 1.6 Ground 2103 Lake Corpus Christi 18,256 257,260 2002 0.53 Ground 2116 Choke Canyon Reservoir 25,989 695,271 1993 3.7 Ground 2303 International Falcon 85,195 2,646,817 ― 1.2 Ground

Surface Volumetric Retention Retention Segment Volume Lake/Reservoir Name Area Survey Time Time No. (acre-ft.) (acres) Year (yrs) Source* Reservoir International Amistad 2305 65,597 3,275,532 1994 2.1 Ground Reservoir 2312 Red Bluff Reservoir 11,193 289,670 ― 2.8 Ground (2454) Cox Creek Lake 541 5,034 ― ― ―

(a) Dimensions obtained from http://findlakes.com (b) Surface area proportions derived from http://www.tpwd.state.tx.us and then adjusted to the surface area at normal pool elevation (c) Capacity from http://www.cityoftyler.org (d) Calculated as the difference between the TWDB total capacity for both lakes (80,198 acre-ft) and the City of Tyler’s capacity for Lake Tyler (http://www.cityoftyler.org).

• • Ground: Ground, T. A. 1992. Relationships of Watershed Climate and Geochemical Processes to Trophic Characteristics in Texas Reservoirs. Master of Science thesis. Retention time was calculated using the mean annual discharge from the nearest downstream USGS gage and the mean annual reservoir volume as published by USGS.

TCEQ: Calculated using capacity at conservation pool from TWDB and annual average flow calculated either from the nearest downstream USGS gage or from US Army Corps of Engineers gated flow data.

Appendix G. Transfer of Analytes.

Applicants and Permittees may transfer an analyte from one EPA-approved method to another EPA-approved method as described below. The section below is an excerpt from pages 6-2 and 6-3 of the EPA document Analytical Method Guidance for the Pharmaceutical Manufacturing Point Source Category, EPA 821-B-99-003 (August 1999). Use of this guidance is not intended to be limited to pharmaceutical manufacturing and may be undertaken by any applicant or permittee for any analyte as long as applicable NELAC accreditation for the analyte is obtained.

Transfer of an Analyte Between Methods Some laboratories asked whether a target analyte from one EPA-approved method could be transferred to another EPA-approved method, thereby reducing the number of methods required for monitoring. During development of the Pharmaceuticals Industry final rule, EPA did not evaluate the effect of transferring analytes between methods. On March 28, 1997, when EPA proposed the Streamlining Initiative (now referred to as the performance-based measurement system or “PBMS”), the Agency included a procedure to allow the addition of an analyte to an existing method. This procedure centered on meeting the quality control (QC) acceptance criteria for performance tests for the analyte.

Using PBMS as the basis for transfer of an analyte from one method to another, EPA recommends allowance of a transfer, provided the following conditions are met:

1) The QC tests in the method from which the analyte is transferred must be run as an integral part of the method to which the analyte is transferred, 2) The QC acceptance criteria in the method from which the analyte is transferred must be met when the QC tests are run as an integral part of the method to which the analyte is transferred, and 3) The MDL obtained for the analyte in the method to which the analyte is transferred must be equal to or less than MDL in the method from which the analyte is transferred or less than one third the regulatory compliance limit specified in the permit, whichever is greater.

QC tests in the 600- and 1600-series EPA methods include calibration, calibration verification, initial and ongoing precision and recovery, analysis of blanks, and matrix spike/matrix spike duplicates. EPA recommends that these QC tests be performed and the QC acceptance criteria be met, as follows:

1) When the analyte is transferred to a method, the added analyte must be included in the initial calibration and ongoing calibration checks, and the QC acceptance criteria in the method from which the analyte is transferred must be met for both initial calibration and calibration verification.

2) All initial and ongoing performance tests in the method from which the analyte is transferred must be performed as an integral part of the method to which the analyte is transferred, and the QC acceptance criteria in the method from which the analyte is transferred must be met. The initial and ongoing tests must include a blank with the initial demonstration of performance and with each sample batch.

3) The quality control check or matrix spike/matrix spike duplicate test (whichever is applicable) in the method from which the analyte is transferred must be performed as an integral part of the method to which the analyte is transferred, and the QC acceptance criteria in the method from which the analyte is transferred must be met.

4) An MDL study must be performed for the analyte as an integral part of the method to which the analyte is transferred, and the MDL obtained must be equal to or less than either a) the MDL in the method from which the analyte is transferred or b) one-third the regulatory compliance limit specified in the permit, whichever is greater.

Notes:

1. A possible conflict could arise if the methods are chromatographic (i.e., GC or GC/MS). Some EPA chromatographic methods contain QC tests and QC acceptance criteria for absolute and/or relative retention time. When transferring an analyte between methods, it is unlikely that the two methods would require use of the same chromatographic column and it is therefore unlikely that the retention time criteria in the method from which the analyte is transferred could be met in the method to which the analyte is transferred. To resolve this issue, the absolute and/or relative retention time requirements are waived for the transferred analyte only. If there are absolute and/or relative retention time requirements for the target analytes in the method to which the analyte is transferred, those requirements must continue to be met.

2. Some methods do not contain an MDL, but contain a minimum level of quantitation (ML) for each analyte. MLs were created by multiplying the MDL by 3.18 and rounding. Therefore, for the purpose of establishing that the MDL for a transferred analyte is less than or equal to the MDL in the method from which the analyte is transferred, divide the ML by 3.18 to establish the MDL.

Examples:

Example 1: The final rule requires that certain volatile analytes be determined by EPA Method 524.2. These analytes may be added to EPA Method 1666 or any other approved method provided the three conditions specified above are met.

Example 2: The final rule requires that tert-butyl alcohol, diethylamine, dimethyl sulfoxide, isobutyraldehyde, methyl cellosolve, methyl formate, and triethyl amine be analyzed by EPA Method 1666 or 1671. These analytes may be added to EPA Method 624, 625, or any other approved method provided that the three conditions specified above are met.

Appendix Item 13 Appendix Item 14

DISSOLVED OXYGEN MODELING PERMIT REVIEW CHECKLIST TCEQ WATER QUALITY ASSESSMENT TEAM WATER QUALITY ASSESSMENT SECTION WATER QUALITY DIVISION

Owner: SWWC Utilities, Inc. TPDES Permit Number: WQ0016022001 (TX0141569) Permit Action: Renewal New New/Replace Expired Amendment Other Review: Preliminary Review SRF Review County: Travis Segment Number: 1434 Received Date: 7/28/2022 Completion Date: 4/1/2022 Discharge Route: Wilbarger Creek -> Colorado River Above La Grange (Segment No. 1434)

1. Previous analysis: No Yes Date:

2. Segment 303(d)-listed: No Yes List Date: 2020 Dissolved Oxygen Impairment? No Yes

3. Approved TMDL: No Yes- Include language in memo if for DO 4. Waste Load Evaluation (WLE): No Yes

5. Tidal: Is initial receiving water tidal? No Yes Is the Segment tidal? No Yes

6. Discharge Directly to a Lake: No Yes

7. Watershed Protection rules apply: No Yes N/A 30 TAC CHAPTER 311 Watershed Protection rules (Colorado River Seg. No. 1434 and its tributaries (Seg. 1428 and portion of 1434 upstream of Smithville)) 30 TAC §§309.3(c)

8. Edwards Aquifer Rules apply: No Yes Within or near: Recharge Zone Contributing Zone Transition Zone

9. DO criteria from Standards Implementation Team Worksheet: Wilbarger Creek = 5.0 mg/L Segment 1434 = 6.0 mg/L

10. Existing effluent limits: NA, New permit 11. Effluent analysis oxygen demanding and related constituent concentrations: NA, new permit 12. Proposed wastewater flow and quality:

Phase: Interim I Interim II Final

Page 1 of 3 AR Item 36, Page 001

Q = 0.2 MGD = 0.5 MGD = 0.8 MGD CBOD5 =5 mg/L =5 mg/L =5 mg/L TSS =5 mg/L =5 mg/L =5 mg/L NH3-N =2 mg/L =2 mg/L =2 mg/L DO = 4.0 mg/L = 4.0 mg/L = 4.0 mg/L TP =1 mg/L = 1.0 mg/L = 1.0 mg/L

13. Other dischargers to consider: See model for list of other dischargers

14. Effluent flow path and distances for modeling: Wilbarger Creek (element 164 in model) >10 miles to Segment No. 1434

15. Headwater flow (≥ 7Q2): Table 4 applies? Yes (Freshwater streams, Apr – Oct only) No 0.4 cfs headwater flow assigned to Wilbarger Creek in SS, May, Sum, and Oct seasonal models 0.1 cfs headwater flow assigned to Wilbarger Creek in March seasonal model

16. Basis for analysis: QUAL-TX model DOS BOX QUAL-TX for Windows model QUAL-TX model from WLE CSTR model LA-QUAL model WASP model QUAL2K model Best Professional Judgment (BPJ) None

17. Hydraulics: See model for previously developed Wilbarger Creek hydraulics 18. Modeling Results:

DO Criteria (mg/L): Wilbarger Creek 5.0 / 5.5 (SS) Model Flow Effluent Set Minimum DO (mg/L) March 0.2 MGD 5/2/4.0 6.66 OK SS 0.2 MGD 5/2/4.0 6.45 OK May 0.2 MGD 5/2/4.0 5.90 OK Sum 0.2 MGD 5/2/4.0 5.58 OK Oct 0.2 MGD 5/2/4.0 6.19 OK

March 0.5 MGD 5/2/4.0 6.62 OK SS 0.5 MGD 5/2/4.0 6.42 OK May 0.5 MGD 5/2/4.0 5.88 OK Sum 0.5 MGD 5/2/4.0 5.56 OK Oct 0.5 MGD 5/2/4.0 6.16 OK

March 0.5 MGD 5/2/4.0 6.60 OK SS 0.5 MGD 5/2/4.0 6.38 OK May 0.5 MGD 5/2/4.0 5.86 OK Sum 0.5 MGD 5/2/4.0 5.54 OK Oct 0.5 MGD 5/2/4.0 6.13 OK

Note: Up to 0.2 mg/L below the DO criterion is considered consistent

19. Recommended limits: Phase: Interim I Interim II Final Page 2 of 3 AR Item 36, Page 002

Q = 0.2 MGD = 0.5 MGD = 0.8 MGD CBOD5 =5 mg/L =5 mg/L =5 mg/L NH3-N =2 mg/L =2 mg/L =2 mg/L DO = 4.0 mg/L = 4.0 mg/L = 4.0 mg/L TP =1 mg/L = 1.0 mg/L = 1.0 mg/L

20. WQMP status: Consistent With Update required N/A

21. Files saved as: F:/MODELING/1434/WILB.March.UP8 …/WILB.SS.UP* …/WILB.May.UP8 …/WILB.SUM.UP8 …/WILB.Oct.UP8

22. Documentation: Modeling file with memo (include standards worksheet) WQMP Coordinator: (any permit that requires modification of WLAs in WQMP or TMDL database; include flow information for all outfalls and all phases) Municipals: for WQMP new and amend, name change, add monitoring req, segment change) Municipals: TMDL completed for any constituent, renewal with change in name (paper copy only) new or amend permits (paper and electronic copies) Industrials: TMDL completed for any constituent, renewal with change in flow or name (paper copy only;) new or amend permits (paper and electronic copies) WQMP packet: some municipal permits; provide electronic copy (memo and model input) and hard copy (memo, worksheet, map); not for more stringent effluent limits or <0.2 MGD with uncalibrated (default) QUAL-TX model; see memowqmp.doc for memo language) TMDL team TMDL underway for DO only, new or amend permits; email memo) TMDL completed for any constituent, new or amend permits; email memo) Copy memo to H:\Permrev\WWTP\Section Permit Memos\Modeling Notify Team Leader if: <5/2/6 limits for municipal NH3-N limit < 2 mg/L No effluent limits can be recommended Recommend addition of DO monitoring for an industrial permit Update the Water Quality Application Tracking Database with modeling review assigned date, memo date, modeling review end date, modeling review comments if any, reviewer begin date for the next reviewer and peer review assigned date if any. Enter a new record for Supersedes memo. Update the WQMP tab in the Water Quality Application Tracking Database (municipal renewals only or amend with no changes in loadings; also for new replacing expired if consistent with expired permit – include note to that effect) Permit file with memo to biomonitoring reviewer or municipal/industrial permits team leader as appropriate (sign/date blue sheet)

23. Permit Review by:

________________________________________ Josi Robertson Date

Page 3 of 3 AR Item 36, Page 003

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CNTROL01 WILBARGER CREEK - FROM 'WILB_SUM.UP6' CNTROL02 MARCH (INCL MAR SPRING SPAWNING RUN); UPDATED 1/12/17 CNTROL03 YES ECHO DATA INPUT CNTROL04 NO INTERMEDIATE SUMMARY CNTROL05 NO FINAL REPORT CNTROL06 YES SPECIAL REPORT CNTROL07 NO LINE PRINTER PLOT CNTROL08 NO GRAPHICS CAPABILITY CNTROL09 NO SEQUENCING OUTPUT CNTROL10 YES METRIC UNITS CNTROL11 YES OXYGEN DEPENDENT RATES CNTROL12 NO SENSITIVITY ANALYSIS CNTROL13 NO FLOW AUGMENTATION ENDATA01 MODOPT01 NO TEMPERATURE MODOPT02 NO SALINITY MODOPT03 NO CONSERVATIVE MATERIAL I = CHLORIDES MODOPT04 NO CONSERVATIVE MATERIAL II = MODOPT05 YES DISSOLVED OXYGEN MODOPT06 YES BIOCHEMICAL OXYGEN DEMAND MODOPT07 YES NITROGEN MODOPT08 NO PHOSPHORUS MODOPT09 NO CHLOROPHYLL A MODOPT10 NO MACROPHYTES MODOPT11 NO COLIFORM MODOPT12 NO NONCONSERVATIVE MATERIAL = ENDATA02 PROGRAM MAXIMUM ITERATION LIMIT = 300. PROGRAM PLOT TYPE = 8. PROGRAM FINAL REPORT TYPE = 3. PROGRAM BOD OXYGEN UPTAKE RATE = 2.3 ENDATA03 ENDATA04 ENDATA05 ENDATA06 ENDATA07 REACH ID 1. WC 13019-001 TO FM 685 69.4 66.7 0.3 REACH ID 2. WC FM 685 TO PFLUGER LANE 66.7 66.5 0.2 REACH ID 3. WC PFLUGER LANE TO TIMMERMAN PROP. 66.5 63.5 0.3 REACH ID 4. WC TIMMERMAN PROP. TO SH 130 63.5 61.4 0.3

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REACH ID 5. WC SH 130 TO WEISS LANE 61.4 59.2 0.2 REACH ID 6. WC WEISS LANE TO UN TRIB 59.2 53.4 0.2 REACH ID 7. T1 14548-001 TO WILBARGER CR 1.9 0.0 0.1 REACH ID 8. WC UN TRIB TO CAMERON RD 53.4 51.0 0.3 REACH ID 9. WC CAMERON RD TO 11845-005 51.0 47.7 0.3 REACH ID 10. WC 11845-005 TO GREGG RD 47.7 46.8 0.3 REACH ID 11. WC GREGG RD TO UN TRIB 46.8 43.0 0.2 REACH ID 12. T2 13987-001 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 13. WC UN TRIB TO US 290 43.0 39.6 0.2 REACH ID 14. WC US 290 TO 300M ABOVE 12900 39.6 39.2 0.2 REACH ID 15. WC 300 M ABOVE 12900 TO 12900 39.2 38.9 0.3 REACH ID 16. WC 12900-001 TO UN TRIB 38.9 37.4 0.3 REACH ID 17. T3 14189 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 18. WC UN TRIB TO DITCH 37.4 34.9 0.25 REACH ID 19. T4 14061 TO WILBARGER CR 0.1 0.0 0.1 REACH ID 20. WC DITCH TO PARSON RD 34.9 32.9 0.2 REACH ID 21. WC PARSON RD TO JONES RD 32.9 28.4 0.3 REACH ID 22. WC JONES RD TO COTTONWOOD CR 28.4 25.6 0.2 REACH ID 23. CC IMMED UPSTR OF UNND TRIB 5 6.91 6.9 0.01 REACH ID 24. T5 14642-001 TO COTTONWOOD CR 7.5 0.0 0.1 REACH ID 25. CC UNND TRIB 5 TO WILBARGER CR 6.9 0.0 0.1 REACH ID 26. WC COTTONWOOD CR TO BITTINGS..RD 25.6 23.8 0.3 REACH ID 27. WC BITTINGS TO UPPER ELGIN RIV RD 23.8 19.6 0.3 REACH ID 28. WC UPPER ELGIN RIV RD TO FM 1704 19.6 10.6 0.3 REACH ID 29. WC FM 1704 TO LOWER ELGIN RD 10.6 7.4 0.2 REACH ID 30. WC LOWER ELGIN RD TO COLORADO RIV 7.4 0.0 0.2 ENDATA08 HYDR-1 1. 0.124 0.5 1.917 0.4 0.035 HYDR-1 2. 0.121 0.5 1.612 0.4 0.035 HYDR-1 3. 0.121 0.5 1.612 0.4 0.035 HYDR-1 4. 0.121 0.5 1.612 0.4 0.035 HYDR-1 5. 0.121 0.5 1.612 0.4 0.035 HYDR-1 6. 0.121 0.5 1.612 0.4 0.035 HYDR-1 7. 0.416 0.5 0.591 0.4 0.035 HYDR-1 8. 0.118 0.5 1.308 0.4 0.035 HYDR-1 9. 0.118 0.5 1.308 0.4 0.035 HYDR-1 10. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 11. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 12. 0.131 0.5 0.720 0.4 0.035 HYDR-1 13. 0.2917 0.5 0.640 0.4 0.035

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HYDR-1 14. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 15. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 16. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 17. 0.131 0.5 0.720 0.4 0.035 HYDR-1 18. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 19. 0.131 0.5 0.720 0.4 0.035 HYDR-1 20. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 21. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 22. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 23. 0.131 0.5 0.720 0.4 0.035 HYDR-1 24. 0.131 0.5 0.720 0.4 0.035 HYDR-1 25. 0.131 0.5 0.720 0.4 0.035 HYDR-1 26. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 27. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 28. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 29. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 30. 0.2917 0.5 0.640 0.4 0.035 ENDATA09 ENDATA10 INITIAL 1. 0.0 6.0 0.05 1. 0. INITIAL 2. 0.0 6.0 0.05 1. 0. INITIAL 3. 0.0 6.0 0.05 1. 0. INITIAL 4. 0.0 6.0 0.05 1. 0. INITIAL 5. 0.0 6.0 0.05 1. 0. INITIAL 6. 0.0 6.0 0.05 1. 0. INITIAL 7. 0.0 6.0 0.05 1. 0. INITIAL 8. 0.0 6.0 0.05 1. 0. INITIAL 9. 0.0 6.0 0.05 1. 0. INITIAL 10. 21.3 6.0 0.05 1. 0. INITIAL 11. 21.3 6.0 0.05 1. 0. INITIAL 12. 21.3 6.0 0.05 1. 0. INITIAL 13. 21.3 6.0 0.05 1. 0. INITIAL 14. 21.3 6.0 0.05 1. 0. INITIAL 15. 21.3 6.0 0.05 1. 0. INITIAL 16. 21.3 6.0 0.05 1. 0. INITIAL 17. 21.3 6.0 0.05 1. 0. INITIAL 18. 21.3 6.0 0.05 1. 0. INITIAL 19. 21.3 6.0 0.05 1. 0. INITIAL 20. 21.3 6.0 0.05 1. 0. INITIAL 21. 21.3 6.0 0.05 1. 0.

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INITIAL 22. 21.3 6.0 0.05 1. 0. INITIAL 23. 0.0 6.0 0.05 1. 0. INITIAL 24. 21.3 6.0 0.05 1. 0. INITIAL 25. 21.3 6.0 0.05 1. 0. INITIAL 26. 21.3 6.0 0.05 1. 0. INITIAL 27. 21.3 6.0 0.05 1. 0. INITIAL 28. 21.3 6.0 0.05 1. 0. INITIAL 29. 21.3 6.0 0.05 1. 0. INITIAL 30. 21.3 6.0 0.05 1. 0. ENDATA11 COEF-1 1. 11. .35 .1 .0 1.0 .0 COEF-1 2. 11. .35 .1 .0 1.0 .0 COEF-1 3. 11. .35 .1 .0 1.0 .0 COEF-1 4. 11. .35 .1 .0 1.0 .0 COEF-1 5. 11. .35 .1 .0 1.0 .0 COEF-1 6. 11. .35 .1 .0 1.0 .0 COEF-1 7. 11. .35 .1 .0 1.0 .0 COEF-1 8. 11. .35 .1 .0 1.0 .0 COEF-1 9. 11. .35 .1 .0 1.0 .0 COEF-1 10. 11. .35 .1 .0 1.0 .0 COEF-1 11. 11. .35 .1 .0 1.0 .0 COEF-1 12. 11. .35 .1 .0 1.0 .0 COEF-1 13. 11. .35 .1 .0 1.0 .0 COEF-1 14. 11. .35 .1 .0 1.0 .0 COEF-1 15. 11. .35 .1 .0 1.0 .0 COEF-1 16. 11. .35 .1 .0 1.0 .0 COEF-1 17. 11. .35 .1 .0 1.0 .0 COEF-1 18. 11. .35 .1 .0 1.0 .0 COEF-1 19. 11. .35 .1 .0 1.0 .0 COEF-1 20. 11. .35 .1 .0 1.0 .0 COEF-1 21. 11. .35 .1 .0 1.0 .0 COEF-1 22. 11. .35 .1 .0 1.0 .0 COEF-1 23. 11. .35 .1 .0 1.0 .0 COEF-1 24. 11. .35 .1 .0 1.0 .0 COEF-1 25. 11. .35 .1 .0 1.0 .0 COEF-1 26. 11. .35 .1 .0 1.0 .0 COEF-1 27. 11. .35 .1 .0 1.0 .0 COEF-1 28. 11. .35 .1 .0 1.0 .0 COEF-1 29. 11. .35 .1 .0 1.0 .0 COEF-1 30. 11. .35 .1 .0 1.0 .0

AR Item 36, Page 008

ENDATA12 COEF-2 1. 0.00 0.00 1.0 0.3 0.0 COEF-2 2. 0.00 0.00 1.0 0.3 0.0 COEF-2 3. 0.00 0.00 1.0 0.3 0.0 COEF-2 4. 0.00 0.00 1.0 0.3 0.0 COEF-2 5. 0.00 0.00 1.0 0.3 0.0 COEF-2 6. 0.00 0.00 1.0 0.3 0.0 COEF-2 7. 0.00 0.00 1.0 0.3 0.0 COEF-2 8. 0.00 0.00 1.0 0.3 0.0 COEF-2 9. 0.00 0.00 1.0 0.3 0.0 COEF-2 10. 0.00 0.00 1.0 0.3 0.0 COEF-2 11. 0.00 0.00 1.0 0.3 0.0 COEF-2 12. 0.00 0.00 1.0 0.3 0.0 COEF-2 13. 0.00 0.00 1.0 0.3 0.0 COEF-2 14. 0.00 0.00 1.0 0.3 0.0 COEF-2 15. 0.00 0.00 1.0 0.3 0.0 COEF-2 16. 0.00 0.00 1.0 0.3 0.0 COEF-2 17. 0.00 0.00 1.0 0.3 0.0 COEF-2 18. 0.00 0.00 1.0 0.3 0.0 COEF-2 19. 0.00 0.00 1.0 0.3 0.0 COEF-2 20. 0.00 0.00 1.0 0.3 0.0 COEF-2 21. 0.00 0.00 1.0 0.3 0.0 COEF-2 22. 0.00 0.00 1.0 0.3 0.0 COEF-2 23. 0.00 0.00 1.0 0.3 0.0 COEF-2 24. 0.00 0.00 1.0 0.3 0.0 COEF-2 25. 0.00 0.00 1.0 0.3 0.0 COEF-2 26. 0.00 0.00 1.0 0.3 0.0 COEF-2 27. 0.00 0.00 1.0 0.3 0.0 COEF-2 28. 0.00 0.00 1.0 0.3 0.0 COEF-2 29. 0.00 0.00 1.0 0.3 0.0 COEF-2 30. 0.00 0.00 1.0 0.3 0.0 ENDATA13 ENDATA14 ENDATA15 INCR-1 29. .00340 INCR-1 30. .01614 ENDATA16 INCR-2 29. 7.07 1.3 0.50 0.05 0.20 INCR-2 30. 7.07 1.3 0.50 0.05 0.20 ENDATA17

AR Item 36, Page 009

ENDATA18 ENDATA19 HDWTR-1 1. WILBARGER CREEK 0.00000 HDWTR-1 68. UN TRIB 1 0.00000 HDWTR-1 128. UN TRIB 2 0.00000 HDWTR-1 157. UN TRIB 3 0.00000 HDWTR-1 171. UN TRIB 4/DITCH 0.00000 HDWTR-1 211. COTTONWOOD CR 0.00000 HDWTR-1 212. UN TRIB 5 0.00000 ENDATA20 HDWTR-2 1. 7.07 1.3 0.50 0.05 0.20 HDWTR-2 68. 7.07 1.3 0.50 0.05 0.20 HDWTR-2 128. 7.07 1.3 0.50 0.05 0.20 HDWTR-2 157. 7.07 1.3 0.50 0.05 0.20 HDWTR-2 171. 7.07 1.3 0.50 0.05 0.20 HDWTR-2 211. 7.07 1.3 0.50 0.05 0.20 HDWTR-2 212. 7.07 1.3 0.50 0.05 0.20 ENDATA21 ENDATA22 JUNCTION 87 67 CONFLUENCE OF UN TRIB 1 WITH WILBARGER CREEK JUNCTION 132 127 CONFLUENCE OF UN TRIB 2 WITH WILBARGER CREEK JUNCTION 161 156 CONFLUENCE OF UN TRIB 3 WITH WILBARGER CREEK JUNCTION 172 170 CONFLUENCE OF UN TRIB 4 (DITCH) WITH WILBARGER CREEK JUNCTION 287 211 CONFLUENCE OF UN TRIB 5 WITH COTTONWOOD CREEK JUNCTION 356 210 CONFLUENCE OF COTTONWOOD CREEK WITH WILBARGER CREEK ENDATA23 WSTLD-1 1. PFLUGERVIL 13019-001 .00000 WSTLD-1 22. TRANSITION TO 5 DO .00000 WSTLD-1 68. 130 CACTUS 14548-001 .00000 WSTLD-1 106. PERENNIAL HDWATER Q .00283 WSTLD-1 106. PFLUGERVIL 11845-005 .69017 WSTLD-1 128. PRELIM ANALYSIS WWTP .00000 WSTLD-1 128. SG LANDHLD 13987-001 .00592 WSTLD-1 152. MANOR 12900-001 .08764 WSTLD-1 157. WILB MUD 2 14189-001 .08764 WSTLD-1 164. SWWC UTLTS 16022-001 .02191 WSTLD-1 171. AQUASOURCE 14061-001 .03506 WSTLD-1 212. PFLUG/COTT 14642-001 .13146 WSTLD-1 301. MANOR/COTT 14129-002 .02191 ENDATA24

AR Item 36, Page 010

WSTLD-2 1. 6.0 5.0 1.8 WSTLD-2 22. 7.07 1.3 0.05 WSTLD-2 68. 5.0 5.0 2.0 WSTLD-2 106. 7.07 1.3 0.05 WSTLD-2 106. 6.0 5.0 1.6 WSTLD-2 128. 7.07 1.3 0.05 WSTLD-2 128. 3.0 5.0 2.0 WSTLD-2 152. 6.0 5.0 2.0 WSTLD-2 157. 6.0 5.0 1.7 WSTLD-2 164. 4.0 5.0 2.0 WSTLD-2 171. 4.0 5.0 2.0 WSTLD-2 212. 4.0 5.0 2.0 WSTLD-2 301. 5.0 5.0 2.0 ENDATA25 ENDATA26 ENDATA27 ENDATA28 ENDATA29 ENDATA30 ENDATA31

AR Item 36, Page 011

CNTROL01 WILBARGER CREEK - FROM 'WILB_SUM.UP7' CNTROL02 SPRING SPAWNING (APR & MAY); UPDATED 7/24/19 CNTROL03 YES ECHO DATA INPUT CNTROL04 NO INTERMEDIATE SUMMARY CNTROL05 NO FINAL REPORT CNTROL06 YES SPECIAL REPORT CNTROL07 NO LINE PRINTER PLOT CNTROL08 NO GRAPHICS CAPABILITY CNTROL09 NO SEQUENCING OUTPUT CNTROL10 YES METRIC UNITS CNTROL11 YES OXYGEN DEPENDENT RATES CNTROL12 NO SENSITIVITY ANALYSIS CNTROL13 NO FLOW AUGMENTATION ENDATA01 MODOPT01 NO TEMPERATURE MODOPT02 NO SALINITY MODOPT03 NO CONSERVATIVE MATERIAL I = CHLORIDES MODOPT04 NO CONSERVATIVE MATERIAL II = MODOPT05 YES DISSOLVED OXYGEN MODOPT06 YES BIOCHEMICAL OXYGEN DEMAND MODOPT07 YES NITROGEN MODOPT08 NO PHOSPHORUS MODOPT09 NO CHLOROPHYLL A MODOPT10 NO MACROPHYTES MODOPT11 NO COLIFORM MODOPT12 NO NONCONSERVATIVE MATERIAL = ENDATA02 PROGRAM MAXIMUM ITERATION LIMIT = 300. PROGRAM PLOT TYPE = 8. PROGRAM FINAL REPORT TYPE = 3. PROGRAM BOD OXYGEN UPTAKE RATE = 2.3 ENDATA03 ENDATA04 ENDATA05 ENDATA06 ENDATA07 REACH ID 1. WC 13019-001 TO FM 685 69.4 66.7 0.3 REACH ID 2. WC FM 685 TO PFLUGER LANE 66.7 66.5 0.2 REACH ID 3. WC PFLUGER LANE TO TIMMERMAN PROP. 66.5 63.5 0.3 REACH ID 4. WC TIMMERMAN PROP. TO SH 130 63.5 61.4 0.3

AR Item 36, Page 012

REACH ID 5. WC SH 130 TO WEISS LANE 61.4 59.2 0.2 REACH ID 6. WC WEISS LANE TO UN TRIB 59.2 53.4 0.2 REACH ID 7. T1 14548-001 TO WILBARGER CR 1.9 0.0 0.1 REACH ID 8. WC UN TRIB TO CAMERON RD 53.4 51.0 0.3 REACH ID 9. WC CAMERON RD TO 11845-005 51.0 47.7 0.3 REACH ID 10. WC 11845-005 TO GREGG RD 47.7 46.8 0.3 REACH ID 11. WC GREGG RD TO UN TRIB 46.8 43.0 0.2 REACH ID 12. T2 13987-001 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 13. WC UN TRIB TO US 290 43.0 39.6 0.2 REACH ID 14. WC US 290 TO 300M ABOVE 12900 39.6 39.2 0.2 REACH ID 15. WC 300 M ABOVE 12900 TO 12900 39.2 38.9 0.3 REACH ID 16. WC 12900-001 TO UN TRIB 38.9 37.4 0.3 REACH ID 17. T3 14189 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 18. WC UN TRIB TO DITCH 37.4 34.9 0.25 REACH ID 19. T4 14061 TO WILBARGER CR 0.1 0.0 0.1 REACH ID 20. WC DITCH TO PARSON RD 34.9 32.9 0.2 REACH ID 21. WC PARSON RD TO JONES RD 32.9 28.4 0.3 REACH ID 22. WC JONES RD TO COTTONWOOD CR 28.4 25.6 0.2 REACH ID 23. CC IMMED UPSTR OF UNND TRIB 5 6.91 6.9 0.01 REACH ID 24. T5 14642-001 TO COTTONWOOD CR 7.5 0.0 0.1 REACH ID 25. CC UNND TRIB 5 TO WILBARGER CR 6.9 0.0 0.1 REACH ID 26. WC COTTONWOOD CR TO BITTINGS..RD 25.6 23.8 0.3 REACH ID 27. WC BITTINGS TO UPPER ELGIN RIV RD 23.8 19.6 0.3 REACH ID 28. WC UPPER ELGIN RIV RD TO FM 1704 19.6 10.6 0.3 REACH ID 29. WC FM 1704 TO LOWER ELGIN RD 10.6 7.4 0.2 REACH ID 30. WC LOWER ELGIN RD TO COLORADO RIV 7.4 0.0 0.2 ENDATA08 HYDR-1 1. 0.124 0.5 1.917 0.4 0.035 HYDR-1 2. 0.121 0.5 1.612 0.4 0.035 HYDR-1 3. 0.121 0.5 1.612 0.4 0.035 HYDR-1 4. 0.121 0.5 1.612 0.4 0.035 HYDR-1 5. 0.121 0.5 1.612 0.4 0.035 HYDR-1 6. 0.121 0.5 1.612 0.4 0.035 HYDR-1 7. 0.416 0.5 0.591 0.4 0.035 HYDR-1 8. 0.118 0.5 1.308 0.4 0.035 HYDR-1 9. 0.118 0.5 1.308 0.4 0.035 HYDR-1 10. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 11. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 12. 0.131 0.5 0.720 0.4 0.035 HYDR-1 13. 0.2917 0.5 0.640 0.4 0.035

AR Item 36, Page 013

HYDR-1 14. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 15. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 16. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 17. 0.131 0.5 0.720 0.4 0.035 HYDR-1 18. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 19. 0.131 0.5 0.720 0.4 0.035 HYDR-1 20. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 21. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 22. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 23. 0.131 0.5 0.720 0.4 0.035 HYDR-1 24. 0.131 0.5 0.720 0.4 0.035 HYDR-1 25. 0.131 0.5 0.720 0.4 0.035 HYDR-1 26. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 27. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 28. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 29. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 30. 0.2917 0.5 0.640 0.4 0.035 ENDATA09 ENDATA10 INITIAL 1. 0.0 6.0 0.05 1. 0. INITIAL 2. 0.0 6.0 0.05 1. 0. INITIAL 3. 0.0 6.0 0.05 1. 0. INITIAL 4. 0.0 6.0 0.05 1. 0. INITIAL 5. 0.0 6.0 0.05 1. 0. INITIAL 6. 0.0 6.0 0.05 1. 0. INITIAL 7. 0.0 6.0 0.05 1. 0. INITIAL 8. 0.0 6.0 0.05 1. 0. INITIAL 9. 0.0 6.0 0.05 1. 0. INITIAL 10. 22.8 6.0 0.05 1. 0. INITIAL 11. 22.8 6.0 0.05 1. 0. INITIAL 12. 22.8 6.0 0.05 1. 0. INITIAL 13. 22.8 6.0 0.05 1. 0. INITIAL 14. 22.8 6.0 0.05 1. 0. INITIAL 15. 22.8 6.0 0.05 1. 0. INITIAL 16. 22.8 6.0 0.05 1. 0. INITIAL 17. 22.8 6.0 0.05 1. 0. INITIAL 18. 22.8 6.0 0.05 1. 0. INITIAL 19. 22.8 6.0 0.05 1. 0. INITIAL 20. 22.8 6.0 0.05 1. 0. INITIAL 21. 22.8 6.0 0.05 1. 0.

AR Item 36, Page 014

INITIAL 22. 22.8 6.0 0.05 1. 0. INITIAL 23. 0.0 6.0 0.05 1. 0. INITIAL 24. 22.8 6.0 0.05 1. 0. INITIAL 25. 22.8 6.0 0.05 1. 0. INITIAL 26. 22.8 6.0 0.05 1. 0. INITIAL 27. 22.8 6.0 0.05 1. 0. INITIAL 28. 22.8 6.0 0.05 1. 0. INITIAL 29. 22.8 6.0 0.05 1. 0. INITIAL 30. 22.8 6.0 0.05 1. 0. ENDATA11 COEF-1 1. 11. .35 .1 .0 1.0 .0 COEF-1 2. 11. .35 .1 .0 1.0 .0 COEF-1 3. 11. .35 .1 .0 1.0 .0 COEF-1 4. 11. .35 .1 .0 1.0 .0 COEF-1 5. 11. .35 .1 .0 1.0 .0 COEF-1 6. 11. .35 .1 .0 1.0 .0 COEF-1 7. 11. .35 .1 .0 1.0 .0 COEF-1 8. 11. .35 .1 .0 1.0 .0 COEF-1 9. 11. .35 .1 .0 1.0 .0 COEF-1 10. 11. .35 .1 .0 1.0 .0 COEF-1 11. 11. .35 .1 .0 1.0 .0 COEF-1 12. 11. .35 .1 .0 1.0 .0 COEF-1 13. 11. .35 .1 .0 1.0 .0 COEF-1 14. 11. .35 .1 .0 1.0 .0 COEF-1 15. 11. .35 .1 .0 1.0 .0 COEF-1 16. 11. .35 .1 .0 1.0 .0 COEF-1 17. 11. .35 .1 .0 1.0 .0 COEF-1 18. 11. .35 .1 .0 1.0 .0 COEF-1 19. 11. .35 .1 .0 1.0 .0 COEF-1 20. 11. .35 .1 .0 1.0 .0 COEF-1 21. 11. .35 .1 .0 1.0 .0 COEF-1 22. 11. .35 .1 .0 1.0 .0 COEF-1 23. 11. .35 .1 .0 1.0 .0 COEF-1 24. 11. .35 .1 .0 1.0 .0 COEF-1 25. 11. .35 .1 .0 1.0 .0 COEF-1 26. 11. .35 .1 .0 1.0 .0 COEF-1 27. 11. .35 .1 .0 1.0 .0 COEF-1 28. 11. .35 .1 .0 1.0 .0 COEF-1 29. 11. .35 .1 .0 1.0 .0 COEF-1 30. 11. .35 .1 .0 1.0 .0

AR Item 36, Page 015

ENDATA12 COEF-2 1. 0.00 0.00 1.0 0.3 0.0 COEF-2 2. 0.00 0.00 1.0 0.3 0.0 COEF-2 3. 0.00 0.00 1.0 0.3 0.0 COEF-2 4. 0.00 0.00 1.0 0.3 0.0 COEF-2 5. 0.00 0.00 1.0 0.3 0.0 COEF-2 6. 0.00 0.00 1.0 0.3 0.0 COEF-2 7. 0.00 0.00 1.0 0.3 0.0 COEF-2 8. 0.00 0.00 1.0 0.3 0.0 COEF-2 9. 0.00 0.00 1.0 0.3 0.0 COEF-2 10. 0.00 0.00 1.0 0.3 0.0 COEF-2 11. 0.00 0.00 1.0 0.3 0.0 COEF-2 12. 0.00 0.00 1.0 0.3 0.0 COEF-2 13. 0.00 0.00 1.0 0.3 0.0 COEF-2 14. 0.00 0.00 1.0 0.3 0.0 COEF-2 15. 0.00 0.00 1.0 0.3 0.0 COEF-2 16. 0.00 0.00 1.0 0.3 0.0 COEF-2 17. 0.00 0.00 1.0 0.3 0.0 COEF-2 18. 0.00 0.00 1.0 0.3 0.0 COEF-2 19. 0.00 0.00 1.0 0.3 0.0 COEF-2 20. 0.00 0.00 1.0 0.3 0.0 COEF-2 21. 0.00 0.00 1.0 0.3 0.0 COEF-2 22. 0.00 0.00 1.0 0.3 0.0 COEF-2 23. 0.00 0.00 1.0 0.3 0.0 COEF-2 24. 0.00 0.00 1.0 0.3 0.0 COEF-2 25. 0.00 0.00 1.0 0.3 0.0 COEF-2 26. 0.00 0.00 1.0 0.3 0.0 COEF-2 27. 0.00 0.00 1.0 0.3 0.0 COEF-2 28. 0.00 0.00 1.0 0.3 0.0 COEF-2 29. 0.00 0.00 1.0 0.3 0.0 COEF-2 30. 0.00 0.00 1.0 0.3 0.0 ENDATA13 ENDATA14 ENDATA15 INCR-1 29. .00340 INCR-1 30. .01614 ENDATA16 INCR-2 29. 6.87 1.3 0.50 0.05 0.20 INCR-2 30. 6.87 1.3 0.50 0.05 0.20 ENDATA17

AR Item 36, Page 016

ENDATA18 ENDATA19 HDWTR-1 1. WILBARGER CREEK 0.00000 HDWTR-1 68. UN TRIB 1 0.00000 HDWTR-1 128. UN TRIB 2 0.00000 HDWTR-1 157. UN TRIB 3 0.00000 HDWTR-1 171. UN TRIB 4/DITCH 0.00000 HDWTR-1 211. COTTONWOOD CR 0.00000 HDWTR-1 212. UN TRIB 5 0.00000 ENDATA20 HDWTR-2 1. 6.87 1.3 0.50 0.05 0.20 HDWTR-2 68. 6.87 1.3 0.50 0.05 0.20 HDWTR-2 128. 6.87 1.3 0.50 0.05 0.20 HDWTR-2 157. 6.87 1.3 0.50 0.05 0.20 HDWTR-2 171. 6.87 1.3 0.50 0.05 0.20 HDWTR-2 211. 6.87 1.3 0.50 0.05 0.20 HDWTR-2 212. 6.87 1.3 0.50 0.05 0.20 ENDATA21 ENDATA22 JUNCTION 87 67 CONFLUENCE OF UN TRIB 1 WITH WILBARGER CREEK JUNCTION 132 127 CONFLUENCE OF UN TRIB 2 WITH WILBARGER CREEK JUNCTION 161 156 CONFLUENCE OF UN TRIB 3 WITH WILBARGER CREEK JUNCTION 172 170 CONFLUENCE OF UN TRIB 4 (DITCH) WITH WILBARGER CREEK JUNCTION 287 211 CONFLUENCE OF UN TRIB 5 WITH COTTONWOOD CREEK JUNCTION 356 210 CONFLUENCE OF COTTONWOOD CREEK WITH WILBARGER CREEK ENDATA23 WSTLD-1 1. PFLUGERVIL 13019-001 .00000 WSTLD-1 22. TRANSITION TO 5 DO .00000 WSTLD-1 68. 130 CACTUS 14548-001 .00000 WSTLD-1 106. TABLE 4 HEADWATER Q .01133 WSTLD-1 106. PFLUGERVIL 11845-005 .69017 WSTLD-1 128. PRELIM ANALYSIS WWTP .00000 WSTLD-1 128. SG LANDHLD 13987-001 .00592 WSTLD-1 152. MANOR 12900-001 .08764 WSTLD-1 157. WILB MUD 2 14189-001 .08764 WSTLD-1 164. SWWC UTLTS 16022-001 .03506 WSTLD-1 171. AQUASOURCE 14061-001 .02147 WSTLD-1 212. PFLUG/COTT 14642-001 .13146 WSTLD-1 301. MANOR/COTT 14129-002 .02191 ENDATA24

AR Item 36, Page 017

WSTLD-2 1. 6.0 5.0 1.8 WSTLD-2 22. 6.87 1.3 0.05 WSTLD-2 68. 5.0 5.0 2.0 WSTLD-2 106. 6.87 1.3 0.05 WSTLD-2 106. 6.0 5.0 1.6 WSTLD-2 128. 6.87 1.3 0.05 WSTLD-2 128. 3.0 5.0 2.0 WSTLD-2 152. 6.0 5.0 2.0 WSTLD-2 157. 6.0 5.0 1.7 WSTLD-2 164. 4.0 5.0 2.0 WSTLD-2 171. 4.0 5.0 2.0 WSTLD-2 212. 4.0 5.0 2.0 WSTLD-2 301. 5.0 5.0 2.0 ENDATA25 ENDATA26 ENDATA27 ENDATA28 ENDATA29 ENDATA30 ENDATA31

AR Item 36, Page 018

CNTROL01 WILBARGER CREEK - FROM 'WILB_SUM.UP7' CNTROL02 MAY; UPDATED 7/24/19 CNTROL03 YES ECHO DATA INPUT CNTROL04 NO INTERMEDIATE SUMMARY CNTROL05 NO FINAL REPORT CNTROL06 YES SPECIAL REPORT CNTROL07 NO LINE PRINTER PLOT CNTROL08 NO GRAPHICS CAPABILITY CNTROL09 NO SEQUENCING OUTPUT CNTROL10 YES METRIC UNITS CNTROL11 YES OXYGEN DEPENDENT RATES CNTROL12 NO SENSITIVITY ANALYSIS CNTROL13 NO FLOW AUGMENTATION ENDATA01 MODOPT01 NO TEMPERATURE MODOPT02 NO SALINITY MODOPT03 NO CONSERVATIVE MATERIAL I = CHLORIDES MODOPT04 NO CONSERVATIVE MATERIAL II = MODOPT05 YES DISSOLVED OXYGEN MODOPT06 YES BIOCHEMICAL OXYGEN DEMAND MODOPT07 YES NITROGEN MODOPT08 NO PHOSPHORUS MODOPT09 NO CHLOROPHYLL A MODOPT10 NO MACROPHYTES MODOPT11 NO COLIFORM MODOPT12 NO NONCONSERVATIVE MATERIAL = ENDATA02 PROGRAM MAXIMUM ITERATION LIMIT = 300. PROGRAM PLOT TYPE = 8. PROGRAM FINAL REPORT TYPE = 3. PROGRAM BOD OXYGEN UPTAKE RATE = 2.3 ENDATA03 ENDATA04 ENDATA05 ENDATA06 ENDATA07 REACH ID 1. WC 13019-001 TO FM 685 69.4 66.7 0.3 REACH ID 2. WC FM 685 TO PFLUGER LANE 66.7 66.5 0.2 REACH ID 3. WC PFLUGER LANE TO TIMMERMAN PROP. 66.5 63.5 0.3 REACH ID 4. WC TIMMERMAN PROP. TO SH 130 63.5 61.4 0.3

AR Item 36, Page 019

REACH ID 5. WC SH 130 TO WEISS LANE 61.4 59.2 0.2 REACH ID 6. WC WEISS LANE TO UN TRIB 59.2 53.4 0.2 REACH ID 7. T1 14548-001 TO WILBARGER CR 1.9 0.0 0.1 REACH ID 8. WC UN TRIB TO CAMERON RD 53.4 51.0 0.3 REACH ID 9. WC CAMERON RD TO 11845-005 51.0 47.7 0.3 REACH ID 10. WC 11845-005 TO GREGG RD 47.7 46.8 0.3 REACH ID 11. WC GREGG RD TO UN TRIB 46.8 43.0 0.2 REACH ID 12. T2 13987-001 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 13. WC UN TRIB TO US 290 43.0 39.6 0.2 REACH ID 14. WC US 290 TO 300M ABOVE 12900 39.6 39.2 0.2 REACH ID 15. WC 300 M ABOVE 12900 TO 12900 39.2 38.9 0.3 REACH ID 16. WC 12900-001 TO UN TRIB 38.9 37.4 0.3 REACH ID 17. T3 14189 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 18. WC UN TRIB TO DITCH 37.4 34.9 0.25 REACH ID 19. T4 14061 TO WILBARGER CR 0.1 0.0 0.1 REACH ID 20. WC DITCH TO PARSON RD 34.9 32.9 0.2 REACH ID 21. WC PARSON RD TO JONES RD 32.9 28.4 0.3 REACH ID 22. WC JONES RD TO COTTONWOOD CR 28.4 25.6 0.2 REACH ID 23. CC IMMED UPSTR OF UNNND TRIB 5 6.91 6.9 0.01 REACH ID 24. T5 14642-001 TO COTTONWOOD CR 7.5 0.0 0.1 REACH ID 25. CC UNND TRIB 5 TO WILBARGER CR 6.9 0.0 0.1 REACH ID 26. WC COTTONWOOD CR TO BITTINGS..RD 25.6 23.8 0.3 REACH ID 27. WC BITTINGS TO UPPER ELGIN RIV RD 23.8 19.6 0.3 REACH ID 28. WC UPPER ELGIN RIV RD TO FM 1704 19.6 10.6 0.3 REACH ID 29. WC FM 1704 TO LOWER ELGIN RD 10.6 7.4 0.2 REACH ID 30. WC LOWER ELGIN RD TO COLORADO RIV 7.4 0.0 0.2 ENDATA08 HYDR-1 1. 0.124 0.5 1.917 0.4 0.035 HYDR-1 2. 0.121 0.5 1.612 0.4 0.035 HYDR-1 3. 0.121 0.5 1.612 0.4 0.035 HYDR-1 4. 0.121 0.5 1.612 0.4 0.035 HYDR-1 5. 0.121 0.5 1.612 0.4 0.035 HYDR-1 6. 0.121 0.5 1.612 0.4 0.035 HYDR-1 7. 0.416 0.5 0.591 0.4 0.035 HYDR-1 8. 0.118 0.5 1.308 0.4 0.035 HYDR-1 9. 0.118 0.5 1.308 0.4 0.035 HYDR-1 10. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 11. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 12. 0.131 0.5 0.720 0.4 0.035 HYDR-1 13. 0.2917 0.5 0.640 0.4 0.035

AR Item 36, Page 020

HYDR-1 14. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 15. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 16. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 17. 0.131 0.5 0.720 0.4 0.035 HYDR-1 18. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 19. 0.131 0.5 0.720 0.4 0.035 HYDR-1 20. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 21. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 22. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 23. 0.131 0.5 0.720 0.4 0.035 HYDR-1 24. 0.131 0.5 0.720 0.4 0.035 HYDR-1 25. 0.131 0.5 0.720 0.4 0.035 HYDR-1 26. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 27. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 28. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 29. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 30. 0.2917 0.5 0.640 0.4 0.035 ENDATA09 ENDATA10 INITIAL 1. 0.0 6.0 0.05 1. 0. INITIAL 2. 0.0 6.0 0.05 1. 0. INITIAL 3. 0.0 6.0 0.05 1. 0. INITIAL 4. 0.0 6.0 0.05 1. 0. INITIAL 5. 0.0 6.0 0.05 1. 0. INITIAL 6. 0.0 6.0 0.05 1. 0. INITIAL 7. 0.0 6.0 0.05 1. 0. INITIAL 8. 0.0 6.0 0.05 1. 0. INITIAL 9. 0.0 6.0 0.05 1. 0. INITIAL 10. 26.3 6.0 0.05 1. 0. INITIAL 11. 26.3 6.0 0.05 1. 0. INITIAL 12. 26.3 6.0 0.05 1. 0. INITIAL 13. 26.3 6.0 0.05 1. 0. INITIAL 14. 26.3 6.0 0.05 1. 0. INITIAL 15. 26.3 6.0 0.05 1. 0. INITIAL 16. 26.3 6.0 0.05 1. 0. INITIAL 17. 26.3 6.0 0.05 1. 0. INITIAL 18. 26.3 6.0 0.05 1. 0. INITIAL 19. 26.3 6.0 0.05 1. 0. INITIAL 20. 26.3 6.0 0.05 1. 0. INITIAL 21. 26.3 6.0 0.05 1. 0.

AR Item 36, Page 021

INITIAL 22. 26.3 6.0 0.05 1. 0. INITIAL 23. 0.0 6.0 0.05 1. 0. INITIAL 24. 26.3 6.0 0.05 1. 0. INITIAL 25. 26.3 6.0 0.05 1. 0. INITIAL 26. 26.3 6.0 0.05 1. 0. INITIAL 27. 26.3 6.0 0.05 1. 0. INITIAL 28. 26.3 6.0 0.05 1. 0. INITIAL 29. 26.3 6.0 0.05 1. 0. INITIAL 30. 26.3 6.0 0.05 1. 0. ENDATA11 COEF-1 1. 11. .35 .1 .0 1.0 .0 COEF-1 2. 11. .35 .1 .0 1.0 .0 COEF-1 3. 11. .35 .1 .0 1.0 .0 COEF-1 4. 11. .35 .1 .0 1.0 .0 COEF-1 5. 11. .35 .1 .0 1.0 .0 COEF-1 6. 11. .35 .1 .0 1.0 .0 COEF-1 7. 11. .35 .1 .0 1.0 .0 COEF-1 8. 11. .35 .1 .0 1.0 .0 COEF-1 9. 11. .35 .1 .0 1.0 .0 COEF-1 10. 11. .35 .1 .0 1.0 .0 COEF-1 11. 11. .35 .1 .0 1.0 .0 COEF-1 12. 11. .35 .1 .0 1.0 .0 COEF-1 13. 11. .35 .1 .0 1.0 .0 COEF-1 14. 11. .35 .1 .0 1.0 .0 COEF-1 15. 11. .35 .1 .0 1.0 .0 COEF-1 16. 11. .35 .1 .0 1.0 .0 COEF-1 17. 11. .35 .1 .0 1.0 .0 COEF-1 18. 11. .35 .1 .0 1.0 .0 COEF-1 19. 11. .35 .1 .0 1.0 .0 COEF-1 20. 11. .35 .1 .0 1.0 .0 COEF-1 21. 11. .35 .1 .0 1.0 .0 COEF-1 22. 11. .35 .1 .0 1.0 .0 COEF-1 23. 11. .35 .1 .0 1.0 .0 COEF-1 24. 11. .35 .1 .0 1.0 .0 COEF-1 25. 11. .35 .1 .0 1.0 .0 COEF-1 26. 11. .35 .1 .0 1.0 .0 COEF-1 27. 11. .35 .1 .0 1.0 .0 COEF-1 28. 11. .35 .1 .0 1.0 .0 COEF-1 29. 11. .35 .1 .0 1.0 .0 COEF-1 30. 11. .35 .1 .0 1.0 .0

AR Item 36, Page 022

ENDATA12 COEF-2 1. 0.00 0.00 1.0 0.3 0.0 COEF-2 2. 0.00 0.00 1.0 0.3 0.0 COEF-2 3. 0.00 0.00 1.0 0.3 0.0 COEF-2 4. 0.00 0.00 1.0 0.3 0.0 COEF-2 5. 0.00 0.00 1.0 0.3 0.0 COEF-2 6. 0.00 0.00 1.0 0.3 0.0 COEF-2 7. 0.00 0.00 1.0 0.3 0.0 COEF-2 8. 0.00 0.00 1.0 0.3 0.0 COEF-2 9. 0.00 0.00 1.0 0.3 0.0 COEF-2 10. 0.00 0.00 1.0 0.3 0.0 COEF-2 11. 0.00 0.00 1.0 0.3 0.0 COEF-2 12. 0.00 0.00 1.0 0.3 0.0 COEF-2 13. 0.00 0.00 1.0 0.3 0.0 COEF-2 14. 0.00 0.00 1.0 0.3 0.0 COEF-2 15. 0.00 0.00 1.0 0.3 0.0 COEF-2 16. 0.00 0.00 1.0 0.3 0.0 COEF-2 17. 0.00 0.00 1.0 0.3 0.0 COEF-2 18. 0.00 0.00 1.0 0.3 0.0 COEF-2 19. 0.00 0.00 1.0 0.3 0.0 COEF-2 20. 0.00 0.00 1.0 0.3 0.0 COEF-2 21. 0.00 0.00 1.0 0.3 0.0 COEF-2 22. 0.00 0.00 1.0 0.3 0.0 COEF-2 23. 0.00 0.00 1.0 0.3 0.0 COEF-2 24. 0.00 0.00 1.0 0.3 0.0 COEF-2 25. 0.00 0.00 1.0 0.3 0.0 COEF-2 26. 0.00 0.00 1.0 0.3 0.0 COEF-2 27. 0.00 0.00 1.0 0.3 0.0 COEF-2 28. 0.00 0.00 1.0 0.3 0.0 COEF-2 29. 0.00 0.00 1.0 0.3 0.0 COEF-2 30. 0.00 0.00 1.0 0.3 0.0 ENDATA13 ENDATA14 ENDATA15 INCR-1 29. .00340 INCR-1 30. .01614 ENDATA16 INCR-2 29. 6.44 1.3 0.50 0.05 0.20 INCR-2 30. 6.44 1.3 0.50 0.05 0.20 ENDATA17

AR Item 36, Page 023

ENDATA18 ENDATA19 HDWTR-1 1. WILBARGER CREEK 0.00000 HDWTR-1 68. UN TRIB 1 0.00000 HDWTR-1 128. UN TRIB 2 0.00000 HDWTR-1 157. UN TRIB 3 0.00000 HDWTR-1 171. UN TRIB 4/DITCH 0.00000 HDWTR-1 211. COTTONWOOD CR 0.00000 HDWTR-1 212. UN TRIB 5 0.00000 ENDATA20 HDWTR-2 1. 6.44 1.3 0.50 0.05 0.20 HDWTR-2 68. 6.44 1.3 0.50 0.05 0.20 HDWTR-2 128. 6.44 1.3 0.50 0.05 0.20 HDWTR-2 157. 6.44 1.3 0.50 0.05 0.20 HDWTR-2 171. 6.44 1.3 0.50 0.05 0.20 HDWTR-2 211. 6.44 1.3 0.50 0.05 0.20 HDWTR-2 212. 6.44 1.3 0.50 0.05 0.20 ENDATA21 ENDATA22 JUNCTION 87 67 CONFLUENCE OF UN TRIB 1 WITH WILBARGER CREEK JUNCTION 132 127 CONFLUENCE OF UN TRIB 2 WITH WILBARGER CREEK JUNCTION 161 156 CONFLUENCE OF UN TRIB 3 WITH WILBARGER CREEK JUNCTION 172 170 CONFLUENCE OF UN TRIB 4 (DITCH) WITH WILBARGER CREEK JUNCTION 287 211 CONFLUENCE OF UN TRIB 5 WITH COTTONWOOD CREEK JUNCTION 356 210 CONFLUENCE OF COTTONWOOD CREEK WITH WILBARGER CREEK ENDATA23 WSTLD-1 1. PFLUGERVIL 13019-001 .00000 WSTLD-1 22. TRANSITION TO 5 DO .00000 WSTLD-1 68. 130 CACTUS 14548-001 .00000 WSTLD-1 106. TABLE 4 HEADWATER Q .01133 WSTLD-1 106. PFLUGERVIL 11845-005 .69017 WSTLD-1 128. PRELIM ANALYSIS WWTP .00000 WSTLD-1 128. SG LANDHLD 13987-001 .00592 WSTLD-1 152. MANOR 12900-001 .08764 WSTLD-1 157. WILB MUD 2 14189-001 .08764 WSTLD-1 164. SWWC UTLTS 16022-001 .03506 WSTLD-1 171. AQUASOURCE 14061-001 .02147 WSTLD-1 212. PFLUG/COTT 14642-001 .13146 WSTLD-1 301. MANOR/COTT 14129-002 .02191 ENDATA24

AR Item 36, Page 024

WSTLD-2 1. 6.0 5.0 1.8 WSTLD-2 22. 6.44 1.3 0.05 WSTLD-2 68. 5.0 5.0 2.0 WSTLD-2 106. 6.44 1.3 0.05 WSTLD-2 106. 6.0 5.0 1.6 WSTLD-2 128. 6.44 1.3 0.05 WSTLD-2 128. 3.0 5.0 2.0 WSTLD-2 152. 6.0 5.0 2.0 WSTLD-2 157. 6.0 5.0 1.7 WSTLD-2 164. 4.0 5.0 2.0 WSTLD-2 171. 4.0 5.0 2.0 WSTLD-2 212. 4.0 5.0 2.0 WSTLD-2 301. 5.0 5.0 2.0 ENDATA25 ENDATA26 ENDATA27 ENDATA28 ENDATA29 ENDATA30 ENDATA31

AR Item 36, Page 025

CNTROL01 WILBARGER CREEK (7/24/19 VERSION); INCR FLOW CITY OF MANOR CNTROL02 (#14129-002) IN ELEM 301 (COTTONWOOD CREEK) CNTROL03 YES ECHO DATA INPUT CNTROL04 NO INTERMEDIATE SUMMARY CNTROL05 NO FINAL REPORT CNTROL06 YES SPECIAL REPORT CNTROL07 NO LINE PRINTER PLOT CNTROL08 NO GRAPHICS CAPABILITY CNTROL09 NO SEQUENCING OUTPUT CNTROL10 YES METRIC UNITS CNTROL11 YES OXYGEN DEPENDENT RATES CNTROL12 NO SENSITIVITY ANALYSIS CNTROL13 NO FLOW AUGMENTATION ENDATA01 MODOPT01 NO TEMPERATURE MODOPT02 NO SALINITY MODOPT03 NO CONSERVATIVE MATERIAL I = CHLORIDES MODOPT04 NO CONSERVATIVE MATERIAL II = MODOPT05 YES DISSOLVED OXYGEN MODOPT06 YES BIOCHEMICAL OXYGEN DEMAND MODOPT07 YES NITROGEN MODOPT08 NO PHOSPHORUS MODOPT09 NO CHLOROPHYLL A MODOPT10 NO MACROPHYTES MODOPT11 NO COLIFORM MODOPT12 NO NONCONSERVATIVE MATERIAL = ENDATA02 PROGRAM MAXIMUM ITERATION LIMIT = 300. PROGRAM PLOT TYPE = 8. PROGRAM BOD OXYGEN UPTAKE RATE = 2.3 ENDATA03 ENDATA04 ENDATA05 ENDATA06 ENDATA07 REACH ID 1. WC 13019-001 TO FM 685 69.4 66.7 0.3 REACH ID 2. WC FM 685 TO PFLUGER LANE 66.7 66.5 0.2 REACH ID 3. WC PFLUGER LANE TO TIMMERMAN PROP. 66.5 63.5 0.3 REACH ID 4. WC TIMMERMAN PROP. TO SH 130 63.5 61.4 0.3 REACH ID 5. WC SH 130 TO WEISS LANE 61.4 59.2 0.2

AR Item 36, Page 026

REACH ID 6. WC WEISS LANE TO UN TRIB 59.2 53.4 0.2 REACH ID 7. T1 14548-001 TO WILBARGER CR 1.9 0.0 0.1 REACH ID 8. WC UN TRIB TO CAMERON RD 53.4 51.0 0.3 REACH ID 9. WC CAMERON RD TO 11845-005 51.0 47.7 0.3 REACH ID 10. WC 11845-005 TO GREGG RD 47.7 46.8 0.3 REACH ID 11. WC GREGG RD TO UN TRIB 46.8 43.0 0.2 REACH ID 12. T2 13987-001 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 13. WC UN TRIB TO US 290 43.0 39.6 0.2 REACH ID 14. WC US 290 TO 300M ABOVE 12900 39.6 39.2 0.2 REACH ID 15. WC 300 M ABOVE 12900 TO 12900 39.2 38.9 0.3 REACH ID 16. WC 12900-001 TO UN TRIB 38.9 37.4 0.3 REACH ID 17. T3 14189 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 18. WC UN TRIB TO DITCH 37.4 34.9 0.25 REACH ID 19. T4 14061 TO WILBARGER CR 0.1 0.0 0.1 REACH ID 20. WC DITCH TO PARSON RD 34.9 32.9 0.2 REACH ID 21. WC PARSON RD TO JONES RD 32.9 28.4 0.3 REACH ID 22. WC JONES RD TO COTTONWOOD CR 28.4 25.6 0.2 REACH ID 23. CC IMMED UPSTR OF UNND TRIB 5 6.91 6.9 0.01 REACH ID 24. T5 14642-001 TO COTTONWOOD CR 7.5 0.0 0.1 REACH ID 25. CC UNND TRIB 5 TO WILBARGER CR 6.9 0.0 0.1 REACH ID 26. WC COTTONWOOD CR TO BITTINGS..RD 25.6 23.8 0.3 REACH ID 27. WC BITTINGS TO UPPER ELGIN RIV RD 23.8 19.6 0.3 REACH ID 28. WC UPPER ELGIN RIV RD TO FM 1704 19.6 10.6 0.3 REACH ID 29. WC FM 1704 TO LOWER ELGIN RD 10.6 7.4 0.2 REACH ID 30. WC LOWER ELGIN RD TO COLORADO RIV 7.4 0.0 0.2 ENDATA08 HYDR-1 1. 0.124 0.5 1.917 0.4 0.035 HYDR-1 2. 0.121 0.5 1.612 0.4 0.035 HYDR-1 3. 0.121 0.5 1.612 0.4 0.035 HYDR-1 4. 0.121 0.5 1.612 0.4 0.035 HYDR-1 5. 0.121 0.5 1.612 0.4 0.035 HYDR-1 6. 0.121 0.5 1.612 0.4 0.035 HYDR-1 7. 0.416 0.5 0.591 0.4 0.035 HYDR-1 8. 0.118 0.5 1.308 0.4 0.035 HYDR-1 9. 0.118 0.5 1.308 0.4 0.035 HYDR-1 10. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 11. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 12. 0.131 0.5 0.720 0.4 0.035 HYDR-1 13. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 14. 0.2917 0.5 0.640 0.4 0.035

AR Item 36, Page 027

HYDR-1 15. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 16. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 17. 0.131 0.5 0.720 0.4 0.035 HYDR-1 18. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 19. 0.131 0.5 0.720 0.4 0.035 HYDR-1 20. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 21. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 22. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 23. 0.131 0.5 0.720 0.4 0.035 HYDR-1 24. 0.131 0.5 0.720 0.4 0.035 HYDR-1 25. 0.131 0.5 0.720 0.4 0.035 HYDR-1 26. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 27. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 28. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 29. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 30. 0.2917 0.5 0.640 0.4 0.035 ENDATA09 ENDATA10 INITIAL 1. 0.0 6.0 0.05 1. 0. INITIAL 2. 0.0 6.0 0.05 1. 0. INITIAL 3. 0.0 6.0 0.05 1. 0. INITIAL 4. 0.0 6.0 0.05 1. 0. INITIAL 5. 0.0 6.0 0.05 1. 0. INITIAL 6. 0.0 6.0 0.05 1. 0. INITIAL 7. 0.0 6.0 0.05 1. 0. INITIAL 8. 0.0 6.0 0.05 1. 0. INITIAL 9. 0.0 6.0 0.05 1. 0. INITIAL 10. 28.5 6.0 0.05 1. 0. INITIAL 11. 28.5 6.0 0.05 1. 0. INITIAL 12. 28.5 6.0 0.05 1. 0. INITIAL 13. 28.5 6.0 0.05 1. 0. INITIAL 14. 28.5 6.0 0.05 1. 0. INITIAL 15. 28.5 6.0 0.05 1. 0. INITIAL 16. 28.5 6.0 0.05 1. 0. INITIAL 17. 28.5 6.0 0.05 1. 0. INITIAL 18. 28.5 6.0 0.05 1. 0. INITIAL 19. 28.5 6.0 0.05 1. 0. INITIAL 20. 28.5 6.0 0.05 1. 0. INITIAL 21. 28.5 6.0 0.05 1. 0. INITIAL 22. 28.5 6.0 0.05 1. 0.

AR Item 36, Page 028

INITIAL 23. 0.0 6.0 0.05 1. 0. INITIAL 24. 28.5 6.0 0.05 1. 0. INITIAL 25. 28.5 6.0 0.05 1. 0. INITIAL 26. 28.5 6.0 0.05 1. 0. INITIAL 27. 28.5 6.0 0.05 1. 0. INITIAL 28. 28.5 6.0 0.05 1. 0. INITIAL 29. 28.5 6.0 0.05 1. 0. INITIAL 30. 28.5 6.0 0.05 1. 0. ENDATA11 COEF-1 1. 11. .35 .1 .0 1.0 .0 COEF-1 2. 11. .35 .1 .0 1.0 .0 COEF-1 3. 11. .35 .1 .0 1.0 .0 COEF-1 4. 11. .35 .1 .0 1.0 .0 COEF-1 5. 11. .35 .1 .0 1.0 .0 COEF-1 6. 11. .35 .1 .0 1.0 .0 COEF-1 7. 11. .35 .1 .0 1.0 .0 COEF-1 8. 11. .35 .1 .0 1.0 .0 COEF-1 9. 11. .35 .1 .0 1.0 .0 COEF-1 10. 11. .35 .1 .0 1.0 .0 COEF-1 11. 11. .35 .1 .0 1.0 .0 COEF-1 12. 11. .35 .1 .0 1.0 .0 COEF-1 13. 11. .35 .1 .0 1.0 .0 COEF-1 14. 11. .35 .1 .0 1.0 .0 COEF-1 15. 11. .35 .1 .0 1.0 .0 COEF-1 16. 11. .35 .1 .0 1.0 .0 COEF-1 17. 11. .35 .1 .0 1.0 .0 COEF-1 18. 11. .35 .1 .0 1.0 .0 COEF-1 19. 11. .35 .1 .0 1.0 .0 COEF-1 20. 11. .35 .1 .0 1.0 .0 COEF-1 21. 11. .35 .1 .0 1.0 .0 COEF-1 22. 11. .35 .1 .0 1.0 .0 COEF-1 23. 11. .35 .1 .0 1.0 .0 COEF-1 24. 11. .35 .1 .0 1.0 .0 COEF-1 25. 11. .35 .1 .0 1.0 .0 COEF-1 26. 11. .35 .1 .0 1.0 .0 COEF-1 27. 11. .35 .1 .0 1.0 .0 COEF-1 28. 11. .35 .1 .0 1.0 .0 COEF-1 29. 11. .35 .1 .0 1.0 .0 COEF-1 30. 11. .35 .1 .0 1.0 .0 ENDATA12

AR Item 36, Page 029

COEF-2 1. 0.00 0.00 1.0 0.3 0.0 COEF-2 2. 0.00 0.00 1.0 0.3 0.0 COEF-2 3. 0.00 0.00 1.0 0.3 0.0 COEF-2 4. 0.00 0.00 1.0 0.3 0.0 COEF-2 5. 0.00 0.00 1.0 0.3 0.0 COEF-2 6. 0.00 0.00 1.0 0.3 0.0 COEF-2 7. 0.00 0.00 1.0 0.3 0.0 COEF-2 8. 0.00 0.00 1.0 0.3 0.0 COEF-2 9. 0.00 0.00 1.0 0.3 0.0 COEF-2 10. 0.00 0.00 1.0 0.3 0.0 COEF-2 11. 0.00 0.00 1.0 0.3 0.0 COEF-2 12. 0.00 0.00 1.0 0.3 0.0 COEF-2 13. 0.00 0.00 1.0 0.3 0.0 COEF-2 14. 0.00 0.00 1.0 0.3 0.0 COEF-2 15. 0.00 0.00 1.0 0.3 0.0 COEF-2 16. 0.00 0.00 1.0 0.3 0.0 COEF-2 17. 0.00 0.00 1.0 0.3 0.0 COEF-2 18. 0.00 0.00 1.0 0.3 0.0 COEF-2 19. 0.00 0.00 1.0 0.3 0.0 COEF-2 20. 0.00 0.00 1.0 0.3 0.0 COEF-2 21. 0.00 0.00 1.0 0.3 0.0 COEF-2 22. 0.00 0.00 1.0 0.3 0.0 COEF-2 23. 0.00 0.00 1.0 0.3 0.0 COEF-2 24. 0.00 0.00 1.0 0.3 0.0 COEF-2 25. 0.00 0.00 1.0 0.3 0.0 COEF-2 26. 0.00 0.00 1.0 0.3 0.0 COEF-2 27. 0.00 0.00 1.0 0.3 0.0 COEF-2 28. 0.00 0.00 1.0 0.3 0.0 COEF-2 29. 0.00 0.00 1.0 0.3 0.0 COEF-2 30. 0.00 0.00 1.0 0.3 0.0 ENDATA13 ENDATA14 ENDATA15 INCR-1 29. .00340 INCR-1 30. .01614 ENDATA16 INCR-2 29. 6.19 1.3 0.50 0.05 0.20 INCR-2 30. 6.19 1.3 0.50 0.05 0.20 ENDATA17 ENDATA18

AR Item 36, Page 030

ENDATA19 HDWTR-1 1. WILBARGER CREEK 0.00000 HDWTR-1 68. UN TRIB 1 0.00000 HDWTR-1 128. UN TRIB 2 0.00000 HDWTR-1 157. UN TRIB 3 0.00000 HDWTR-1 171. UN TRIB 4/DITCH 0.00000 HDWTR-1 211. COTTONWOOD CR 0.00000 HDWTR-1 212. UN TRIB 5 0.00000 ENDATA20 HDWTR-2 1. 6.19 1.3 0.50 0.05 0.20 HDWTR-2 68. 6.19 1.3 0.50 0.05 0.20 HDWTR-2 128. 6.19 1.3 0.50 0.05 0.20 HDWTR-2 157. 6.19 1.3 0.50 0.05 0.20 HDWTR-2 171. 6.19 1.3 0.50 0.05 0.20 HDWTR-2 211. 6.19 1.3 0.50 0.05 0.20 HDWTR-2 212. 6.19 1.3 0.50 0.05 0.20 ENDATA21 ENDATA22 JUNCTION 87 67 CONFLUENCE OF UN TRIB 1 WITH WILBARGER CREEK JUNCTION 132 127 CONFLUENCE OF UN TRIB 2 WITH WILBARGER CREEK JUNCTION 161 156 CONFLUENCE OF UN TRIB 3 WITH WILBARGER CREEK JUNCTION 172 170 CONFLUENCE OF UN TRIB 4 (DITCH) WITH WILBARGER CREEK JUNCTION 287 211 CONFLUENCE OF UN TRIB 5 WITH COTTONWOOD CREEK JUNCTION 356 210 CONFLUENCE OF COTTONWOOD CREEK WITH WILBARGER CREEK ENDATA23 WSTLD-1 1. PFLUGERVIL 13019-001 .00000 WSTLD-1 22. TRANSITION TO 5 DO .00000 WSTLD-1 68. 130 CACTUS 14548-001 .00000 WSTLD-1 106. TABLE 4 HEADWATER Q .01133 WSTLD-1 106. PFLUGERVIL 11845-005 .69017 WSTLD-1 106. PRE-APP WWTP(APPROX) .00000 WSTLD-1 128. PRELIM ANALYSIS WWTP .00000 WSTLD-1 128. SG LANDHLD 13987-001 .00592 WSTLD-1 152. MANOR 12900-001 .08764 WSTLD-1 157. WILB MUD 2 14189-001 .08764 WSTLD-1 164. SWWC UTLTS 16022-001 .03506 WSTLD-1 171. AQUASOURCE 14061-001 .02147 WSTLD-1 212. PFLUG/COTT 14642-001 .13146 WSTLD-1 301. MANOR/COTT 14129-002 .02191 ENDATA24

AR Item 36, Page 031

WSTLD-2 1. 6.0 5.0 1.8 WSTLD-2 22. 6.19 1.3 0.05 WSTLD-2 68. 5.0 5.0 2.0 WSTLD-2 106. 6.19 1.3 0.05 WSTLD-2 106. 6.0 5.0 1.6 WSTLD-2 106. 6.0 5.0 2.0 WSTLD-2 128. 6.16 2.43 0.15 WSTLD-2 128. 3.0 5.0 2.0 WSTLD-2 152. 6.0 5.0 2.0 WSTLD-2 157. 6.0 5.0 0.7 WSTLD-2 164. 4.0 5.0 2.0 WSTLD-2 171. 4.0 5.0 2.0 WSTLD-2 212. 4.0 5.0 2.0 WSTLD-2 301. 5.0 5.0 2.0 ENDATA25 ENDATA26 ENDATA27 ENDATA28 ENDATA29 ENDATA30 ENDATA31

AR Item 36, Page 032

CNTROL01 WILBARGER CR; FROM 'WILB_SUM.UP7'; OCT; BACK TO SEQUENCING # FOR CNTROL02 DOS QUALTX; OUTPUT FILE SEQUENCES TO OCT COLORADO MAINSTEM MODEL CNTROL03 YES ECHO DATA INPUT CNTROL04 NO INTERMEDIATE SUMMARY CNTROL05 NO FINAL REPORT CNTROL06 YES SPECIAL REPORT CNTROL07 NO LINE PRINTER PLOT CNTROL08 NO GRAPHICS CAPABILITY CNTROL09 YES SEQUENCING OUTPUT CNTROL10 YES METRIC UNITS CNTROL11 YES OXYGEN DEPENDENT RATES CNTROL12 NO SENSITIVITY ANALYSIS CNTROL13 NO FLOW AUGMENTATION ENDATA01 MODOPT01 NO TEMPERATURE MODOPT02 NO SALINITY MODOPT03 NO CONSERVATIVE MATERIAL I = CHLORIDES MODOPT04 NO CONSERVATIVE MATERIAL II = MODOPT05 YES DISSOLVED OXYGEN MODOPT06 YES BIOCHEMICAL OXYGEN DEMAND MODOPT07 YES NITROGEN MODOPT08 NO PHOSPHORUS MODOPT09 NO CHLOROPHYLL A MODOPT10 NO MACROPHYTES MODOPT11 NO COLIFORM MODOPT12 NO NONCONSERVATIVE MATERIAL = ENDATA02 !PROGRAM LOGICAL UNIT NUMBER FOR SEQUENCING = 19. PROGRAM MAXIMUM ITERATION LIMIT = 300. PROGRAM PLOT TYPE = 8. PROGRAM FINAL REPORT TYPE = 3. PROGRAM BOD OXYGEN UPTAKE RATE = 2.3 ENDATA03 ENDATA04 ENDATA05 ENDATA06 ENDATA07 REACH ID 1. WC 13019-001 TO FM 685 69.4 66.7 0.3 REACH ID 2. WC FM 685 TO PFLUGER LANE 66.7 66.5 0.2 REACH ID 3. WC PFLUGER LANE TO TIMMERMAN PROP. 66.5 63.5 0.3

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REACH ID 4. WC TIMMERMAN PROP. TO SH 130 63.5 61.4 0.3 REACH ID 5. WC SH 130 TO WEISS LANE 61.4 59.2 0.2 REACH ID 6. WC WEISS LANE TO UN TRIB 59.2 53.4 0.2 REACH ID 7. T1 14548-001 TO WILBARGER CR 1.9 0.0 0.1 REACH ID 8. WC UN TRIB TO CAMERON RD 53.4 51.0 0.3 REACH ID 9. WC CAMERON RD TO 11845-005 51.0 47.7 0.3 REACH ID 10. WC 11845-005 TO GREGG RD 47.7 46.8 0.3 REACH ID 11. WC GREGG RD TO UN TRIB 46.8 43.0 0.2 REACH ID 12. T2 13987-001 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 13. WC UN TRIB TO US 290 43.0 39.6 0.2 REACH ID 14. WC US 290 TO 300M ABOVE 12900 39.6 39.2 0.2 REACH ID 15. WC 300 M ABOVE 12900 TO 12900 39.2 38.9 0.3 REACH ID 16. WC 12900-001 TO UN TRIB 38.9 37.4 0.3 REACH ID 17. T3 14189 TO WILBARGER CR 0.4 0.0 0.1 REACH ID 18. WC UN TRIB TO DITCH 37.4 34.9 0.25 REACH ID 19. T4 14061 TO WILBARGER CR 0.1 0.0 0.1 REACH ID 20. WC DITCH TO PARSON RD 34.9 32.9 0.2 REACH ID 21. WC PARSON RD TO JONES RD 32.9 28.4 0.3 REACH ID 22. WC JONES RD TO COTTONWOOD CR 28.4 25.6 0.2 REACH ID 23. CC IMMED UPSTR OF UNND TRIB 5 6.91 6.9 0.01 REACH ID 24. T5 14642-001 TO COTTONWOOD CR 7.5 0.0 0.1 REACH ID 25. CC UNND TRIB 5 TO WILBARGER CR 6.9 0.0 0.1 REACH ID 26. WC COTTONWOOD CR TO BITTINGS..RD 25.6 23.8 0.3 REACH ID 27. WC BITTINGS TO UPPER ELGIN RIV RD 23.8 19.6 0.3 REACH ID 28. WC UPPER ELGIN RIV RD TO FM 1704 19.6 10.6 0.3 REACH ID 29. WC FM 1704 TO LOWER ELGIN RD 10.6 7.4 0.2 REACH ID 30. WC LOWER ELGIN RD TO COLORADO RIV 7.4 0.0 0.2 ENDATA08 HYDR-1 1. 0.124 0.5 1.917 0.4 0.035 HYDR-1 2. 0.121 0.5 1.612 0.4 0.035 HYDR-1 3. 0.121 0.5 1.612 0.4 0.035 HYDR-1 4. 0.121 0.5 1.612 0.4 0.035 HYDR-1 5. 0.121 0.5 1.612 0.4 0.035 HYDR-1 6. 0.121 0.5 1.612 0.4 0.035 HYDR-1 7. 0.416 0.5 0.591 0.4 0.035 HYDR-1 8. 0.118 0.5 1.308 0.4 0.035 HYDR-1 9. 0.118 0.5 1.308 0.4 0.035 HYDR-1 10. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 11. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 12. 0.131 0.5 0.720 0.4 0.035

AR Item 36, Page 034

HYDR-1 13. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 14. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 15. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 16. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 17. 0.131 0.5 0.720 0.4 0.035 HYDR-1 18. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 19. 0.131 0.5 0.720 0.4 0.035 HYDR-1 20. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 21. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 22. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 23. 0.131 0.5 0.720 0.4 0.035 HYDR-1 24. 0.131 0.5 0.720 0.4 0.035 HYDR-1 25. 0.131 0.5 0.720 0.4 0.035 HYDR-1 26. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 27. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 28. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 29. 0.2917 0.5 0.640 0.4 0.035 HYDR-1 30. 0.2917 0.5 0.640 0.4 0.035 ENDATA09 ENDATA10 INITIAL 1. 0.0 6.0 0.05 1. 0. INITIAL 2. 0.0 6.0 0.05 1. 0. INITIAL 3. 0.0 6.0 0.05 1. 0. INITIAL 4. 0.0 6.0 0.05 1. 0. INITIAL 5. 0.0 6.0 0.05 1. 0. INITIAL 6. 0.0 6.0 0.05 1. 0. INITIAL 7. 0.0 6.0 0.05 1. 0. INITIAL 8. 0.0 6.0 0.05 1. 0. INITIAL 9. 0.0 6.0 0.05 1. 0. INITIAL 10. 24.5 6.0 0.05 1. 0. INITIAL 11. 24.5 6.0 0.05 1. 0. INITIAL 12. 24.5 6.0 0.05 1. 0. INITIAL 13. 24.5 6.0 0.05 1. 0. INITIAL 14. 24.5 6.0 0.05 1. 0. INITIAL 15. 24.5 6.0 0.05 1. 0. INITIAL 16. 24.5 6.0 0.05 1. 0. INITIAL 17. 24.5 6.0 0.05 1. 0. INITIAL 18. 24.5 6.0 0.05 1. 0. INITIAL 19. 24.5 6.0 0.05 1. 0. INITIAL 20. 24.5 6.0 0.05 1. 0.

AR Item 36, Page 035

INITIAL 21. 24.5 6.0 0.05 1. 0. INITIAL 22. 24.5 6.0 0.05 1. 0. INITIAL 23. 0.0 6.0 0.05 1. 0. INITIAL 24. 24.5 6.0 0.05 1. 0. INITIAL 25. 24.5 6.0 0.05 1. 0. INITIAL 26. 24.5 6.0 0.05 1. 0. INITIAL 27. 24.5 6.0 0.05 1. 0. INITIAL 28. 24.5 6.0 0.05 1. 0. INITIAL 29. 24.5 6.0 0.05 1. 0. INITIAL 30. 24.5 6.0 0.05 1. 0. ENDATA11 COEF-1 1. 11. .35 .1 .0 1.0 .0 COEF-1 2. 11. .35 .1 .0 1.0 .0 COEF-1 3. 11. .35 .1 .0 1.0 .0 COEF-1 4. 11. .35 .1 .0 1.0 .0 COEF-1 5. 11. .35 .1 .0 1.0 .0 COEF-1 6. 11. .35 .1 .0 1.0 .0 COEF-1 7. 11. .35 .1 .0 1.0 .0 COEF-1 8. 11. .35 .1 .0 1.0 .0 COEF-1 9. 11. .35 .1 .0 1.0 .0 COEF-1 10. 11. .35 .1 .0 1.0 .0 COEF-1 11. 11. .35 .1 .0 1.0 .0 COEF-1 12. 11. .35 .1 .0 1.0 .0 COEF-1 13. 11. .35 .1 .0 1.0 .0 COEF-1 14. 11. .35 .1 .0 1.0 .0 COEF-1 15. 11. .35 .1 .0 1.0 .0 COEF-1 16. 11. .35 .1 .0 1.0 .0 COEF-1 17. 11. .35 .1 .0 1.0 .0 COEF-1 18. 11. .35 .1 .0 1.0 .0 COEF-1 19. 11. .35 .1 .0 1.0 .0 COEF-1 20. 11. .35 .1 .0 1.0 .0 COEF-1 21. 11. .35 .1 .0 1.0 .0 COEF-1 22. 11. .35 .1 .0 1.0 .0 COEF-1 23. 11. .35 .1 .0 1.0 .0 COEF-1 24. 11. .35 .1 .0 1.0 .0 COEF-1 25. 11. .35 .1 .0 1.0 .0 COEF-1 26. 11. .35 .1 .0 1.0 .0 COEF-1 27. 11. .35 .1 .0 1.0 .0 COEF-1 28. 11. .35 .1 .0 1.0 .0 COEF-1 29. 11. .35 .1 .0 1.0 .0

AR Item 36, Page 036

COEF-1 30. 11. .35 .1 .0 1.0 .0 ENDATA12 COEF-2 1. 0.00 0.00 1.0 0.3 0.0 COEF-2 2. 0.00 0.00 1.0 0.3 0.0 COEF-2 3. 0.00 0.00 1.0 0.3 0.0 COEF-2 4. 0.00 0.00 1.0 0.3 0.0 COEF-2 5. 0.00 0.00 1.0 0.3 0.0 COEF-2 6. 0.00 0.00 1.0 0.3 0.0 COEF-2 7. 0.00 0.00 1.0 0.3 0.0 COEF-2 8. 0.00 0.00 1.0 0.3 0.0 COEF-2 9. 0.00 0.00 1.0 0.3 0.0 COEF-2 10. 0.00 0.00 1.0 0.3 0.0 COEF-2 11. 0.00 0.00 1.0 0.3 0.0 COEF-2 12. 0.00 0.00 1.0 0.3 0.0 COEF-2 13. 0.00 0.00 1.0 0.3 0.0 COEF-2 14. 0.00 0.00 1.0 0.3 0.0 COEF-2 15. 0.00 0.00 1.0 0.3 0.0 COEF-2 16. 0.00 0.00 1.0 0.3 0.0 COEF-2 17. 0.00 0.00 1.0 0.3 0.0 COEF-2 18. 0.00 0.00 1.0 0.3 0.0 COEF-2 19. 0.00 0.00 1.0 0.3 0.0 COEF-2 20. 0.00 0.00 1.0 0.3 0.0 COEF-2 21. 0.00 0.00 1.0 0.3 0.0 COEF-2 22. 0.00 0.00 1.0 0.3 0.0 COEF-2 23. 0.00 0.00 1.0 0.3 0.0 COEF-2 24. 0.00 0.00 1.0 0.3 0.0 COEF-2 25. 0.00 0.00 1.0 0.3 0.0 COEF-2 26. 0.00 0.00 1.0 0.3 0.0 COEF-2 27. 0.00 0.00 1.0 0.3 0.0 COEF-2 28. 0.00 0.00 1.0 0.3 0.0 COEF-2 29. 0.00 0.00 1.0 0.3 0.0 COEF-2 30. 0.00 0.00 1.0 0.3 0.0 ENDATA13 ENDATA14 ENDATA15 INCR-1 29. .00340 INCR-1 30. .01614 ENDATA16 INCR-2 29. 6.66 1.3 0.50 0.05 0.20 INCR-2 30. 6.66 1.3 0.50 0.05 0.20

AR Item 36, Page 037

ENDATA17 ENDATA18 ENDATA19 HDWTR-1 1. WILBARGER CREEK 0.00000 HDWTR-1 68. UN TRIB 1 0.00000 HDWTR-1 128. UN TRIB 2 0.00000 HDWTR-1 157. UN TRIB 3 0.00000 HDWTR-1 171. UN TRIB 4/DITCH 0.00000 HDWTR-1 211. COTTONWOOD CR 0.00000 HDWTR-1 212. UN TRIB 5 0.00000 ENDATA20 HDWTR-2 1. 6.66 1.3 0.50 0.05 0.20 HDWTR-2 68. 6.66 1.3 0.50 0.05 0.20 HDWTR-2 128. 6.66 1.3 0.50 0.05 0.20 HDWTR-2 157. 6.66 1.3 0.50 0.05 0.20 HDWTR-2 171. 6.66 1.3 0.50 0.05 0.20 HDWTR-2 211. 6.66 1.3 0.50 0.05 0.20 HDWTR-2 212. 6.66 1.3 0.50 0.05 0.20 ENDATA21 ENDATA22 JUNCTION 87 67 CONFLUENCE OF UN TRIB 1 WITH WILBARGER CREEK JUNCTION 132 127 CONFLUENCE OF UN TRIB 2 WITH WILBARGER CREEK JUNCTION 161 156 CONFLUENCE OF UN TRIB 3 WITH WILBARGER CREEK JUNCTION 172 170 CONFLUENCE OF UN TRIB 4 (DITCH) WITH WILBARGER CREEK JUNCTION 287 211 CONFLUENCE OF UN TRIB 5 WITH COTTONWOOD CREEK JUNCTION 356 210 CONFLUENCE OF COTTONWOOD CREEK WITH WILBARGER CREEK ENDATA23 WSTLD-1 1. PFLUGERVIL 13019-001 .00000 WSTLD-1 22. TRANSITION TO 5 DO .00000 WSTLD-1 68. 130 CACTUS 14548-001 .00000 WSTLD-1 106. TABLE 4 HEADWATER Q .01133 WSTLD-1 106. PFLUGERVIL 11845-005 .69017 WSTLD-1 128. PRELIM ANALYSIS WWTP .00000 WSTLD-1 128. SG LANDHLD 13987-001 .00592 WSTLD-1 152. MANOR 12900-001 .08764 WSTLD-1 157. WILB MUD 2 14189-001 .08764 WSTLD-1 164. SWWC UTLTS 16022-001 .03506 WSTLD-1 171. AQUASOURCE 14061-001 .02147 WSTLD-1 212. PFLUG/COTT 14642-001 .13146 WSTLD-1 301. MANOR/COTT 14129-002 .02191

AR Item 36, Page 038

ENDATA24 WSTLD-2 1. 6.0 5.0 1.8 WSTLD-2 22. 6.66 1.3 0.05 WSTLD-2 68. 5.0 5.0 2.0 WSTLD-2 106. 6.66 1.3 0.05 WSTLD-2 106. 6.0 5.0 1.6 WSTLD-2 128. 6.66 1.3 0.05 WSTLD-2 128. 3.0 5.0 2.0 WSTLD-2 152. 6.0 5.0 2.0 WSTLD-2 157. 6.0 5.0 1.7 WSTLD-2 164. 4.0 5.0 2.0 WSTLD-2 171. 4.0 5.0 2.0 WSTLD-2 212. 4.0 5.0 2.0 WSTLD-2 301. 5.0 5.0 2.0 ENDATA25 ENDATA26 ENDATA27 ENDATA28 ENDATA29 ENDATA30 ENDATA31

AR Item 36, Page 039 Appendix Item 15 Appendix Item 16

2020 Texas Integrated Report - Assessment Results for Basin 14 - Colorado River Basin Report Abbreviations Description: SEGID: Unique Segment identification alpha-numeric code; can be stream, reservoir, estuary, oyster waters, beach watch, etc. AUID: Unique Assessment Unit code; this is a portion of the segment the AUID begins with and ends with _01, _02, etc. Some AUIDs are special units ending in "SA," or oyster water AUIDs are indicated by "OW" and beach watch AUIDs are indicated by abbreviations for name of beach in AUID. ASMT Start Date: The start date of the period of record data for this method was selected; the official 20 20 period of record is from 12/1/2011 to 11/30/2018. Assessors have the option of going back 10 years (12/1/2008) to select more data, according to assessment guidance. ASMT End Date: The end date of the period of record data for this method was selected; the official 20 20 period of record dates are 12/1/2011 to 11/30/2018. Assessors have the option of including more recently collected data than 12/01/201 8, if available. # Assd: Number of samples assessed; some data are averaged, as with profile data, some are eliminated because criteria do not apply during certain conditions such a s low flow. Mean Assd: Mean of samples assessed; includes averaged methods like chronic criteria as well as geometric mean calculations for bacteria. # Exceed: The number of samples that exceed criteria for single sample, or binomial, methods (not averaged data). Mean Exceed: This is the mean of the samples that exceeded criteria for the single sample, or binomial, methods (not averaged data). Criteria: Value that the data is compared against to determine level of support; Note: for acute metals in water, each value is compare d to a calculated criterion and not all criteria could be reported here, only the minimum in the range of criteria calculated are included. DS Qual: Dataset Qualifier - indicates sample sizes: AD = Adequate Data (10 or more samples) TR = Temporally Not Representative, used with NA LD = Limited Data (less than 9, greater than 3) SR = Spatially Not Representative, used with NA ID = Inadequate Data (less than 4) OE = Other information than ambient samples evaluated JQ = Level of support is based on judgment of the assessor OS = Assessment area outside state boundaries SM = This assessment method is superseded by another method LOS: Level of support for this use, method, assessment parameter: FS = Fully Supporting NS = Nonsupport NC = No Concern CS = Screening Level Concern NA = Not Assessed CN = Use Concern CF: Carry forward indicator check box: indicates that the Integrated level of support of CS, CN, or NS was carried forward from a previous assessment due to inadequate data for this method in this assessment. Int LOS: Integrated level of support. This is the overall level of support for this use, method, parameter group, which could be different from t he LOS (described above) due to carry forward information or other types of changes. New Code added in 2010: PI = Pending Issue TCEQ Cause: This is the impairment description (e.g., bacteria, depressed dissolved oxygen, etc.) Cat: Category 3: Insufficient or no data and information to determine if standard is attained Category 4: Standard is not attained or nonattainment is predicted in the near future due to one or more parameters, but no TMDLs are required. 4a - All TMDLs have been completed and approved by EPA. 4b - Other pollution control requirements are reasonably expected to result in the attainment of the water qualit y standard in the near future. 4c - Nonattainment of the standard for one or more parameters is shown to be caused by pollution, n ot by pollutants and that the water quality conditions cannot be changed by the allocation and control of pollutants through the TMDL process. Category 5: Standard is not attained or nonattainment is predicted in the near future for one or more parameters. 5a - TMDLs are underway, scheduled, or may be scheduled for one or more parameters. 5b - review of the standards for one or more parameters will be conducted before a management strategy is selected, including a possible revision to the water quality standards. 5c - Additional data or information will be collected and/or evaluated for one or more parameters before a man agement strategy is selected.

AR Item 42, Page 001 May 12, 2020 Page 1 of 242

2020 Texas Integrated Report - Assessment Results for Basin 14 - Colorado River Basin SEGID: 1434 Colorado River above La Grange

AUID: 1434_01 From a point 100 m downstream of SH 71 upstream to the Southern Pacific Railroad crossing

Aquatic Life Use Data Assessed Exceedances Data Int Method Parameter Period of Record Criteria # Value # Value Qual LOS CF LOS TCEQ Cause Cat

Dissolved Oxygen grab minimum Dissolved Oxygen Grab 12/01/11 - 11/30/18 4 40 0 AD FS o FS Dissolved Oxygen grab screening level Dissolved Oxygen Grab 12/01/11 - 11/30/18 6 40 0 AD NC o NC

Recreation Use Data Assessed Exceedances Data Int Method Parameter Period of Record Criteria # Value # Value Qual LOS CF LOS TCEQ Cause Cat

Bacteria Geomean E. coli 12/01/11 - 11/30/18 126 40 60.01 0 AD FS o FS

General Use Data Assessed Exceedances Data Int Method Parameter Period of Record Criteria # Value # Value Qual LOS CF LOS TCEQ Cause Cat

Dissolved Solids Chloride 12/01/11 - 11/30/18 100 118 53.67 0 AD FS o FS Dissolved Solids Sulfate 12/01/11 - 11/30/18 100 117 66.62 0 AD FS o FS Dissolved Solids Total Dissolved Solids 12/01/11 - 11/30/18 500 119 423.96 0 AD FS o FS High pH pH 12/01/11 - 11/30/18 9 40 1 9.20 AD FS o FS Low pH pH 12/01/11 - 11/30/18 6.50 40 0 AD FS o FS Nutrient Screening Levels Ammonia 12/01/11 - 11/30/18 0.33 40 0 AD NC o NC Nutrient Screening Levels Chlorophyll-a 12/01/11 - 11/30/18 14.10 39 6 65.28 AD NC o NC Nutrient Screening Levels Nitrate 12/01/11 - 11/30/18 1.95 40 35 3.61 AD CS o CS Nitrate in water Nutrient Screening Levels Total Phosphorus 12/01/11 - 11/30/18 0.69 40 13 0.93 AD CS o CS Total Phosphorus in water Water Temperature Water temperature 12/01/11 - 11/30/18 35 40 0 AD FS o FS

Domestic Water Supply Use Data Assessed Exceedances Data Int Method Parameter Period of Record Criteria # Value # Value Qual LOS CF LOS TCEQ Cause Cat

Surface Water HH criteria for DWS average Nitrate 12/01/11 - 11/30/18 10 117 4.30 0 AD FS o FS

AR Item 42, Page 002 May 12, 2020 Page 230 of 242

2020 Texas Integrated Report - Assessment Results for Basin 14 - Colorado River Basin SEGID: 1434D Wilbarger Creek

AUID: 1434D_01 From the confluence with the Colorado River at Hemphill Bend in Bastrop County upstream to the confluence with Cottonwood Creek

Aquatic Life Use Data Assessed Exceedances Data Int Method Parameter Period of Record Criteria # Value # Value Qual LOS CF LOS TCEQ Cause Cat

Dissolved Oxygen grab minimum Dissolved Oxygen Grab 12/01/11 - 11/30/18 3 16 0 AD FS o FS Dissolved Oxygen grab screening level Dissolved Oxygen Grab 12/01/11 - 11/30/18 5 16 1 4.70 AD NC o NC

Recreation Use Data Assessed Exceedances Data Int Method Parameter Period of Record Criteria # Value # Value Qual LOS CF LOS TCEQ Cause Cat

Bacteria Geomean E. coli 12/01/11 - 11/30/18 126 11 157.42 1 LD CN o CN Bacteria in water

General Use Data Assessed Exceedances Data Int Method Parameter Period of Record Criteria # Value # Value Qual LOS CF LOS TCEQ Cause Cat

Nutrient Screening Levels Ammonia 12/01/11 - 11/30/18 0.33 18 0 AD NC o NC Nutrient Screening Levels Chlorophyll-a 12/01/11 - 11/30/18 14.10 18 5 69.78 AD NC o NC Nutrient Screening Levels Nitrate 12/01/11 - 11/30/18 1.95 17 3 2.84 AD NC o NC Nutrient Screening Levels Total Phosphorus 12/01/11 - 11/30/18 0.69 16 0 AD NC o NC

AR Item 42, Page 003 May 12, 2020 Page 237 of 242

2020 Texas Integrated Report Water Bodies with Concerns for Use Attainment and Screening Levels

Explanation of Column Headings

SegID and Name: The unique identifier (SegID), segment name, and location of the water body. Items may be one of three types of numbers for SegID. The first type is a classified segment number (4 digits, e.g. 0218), as defined in the Texas Surface Water Quality Standards (TSWQS). The second type is an unclassified water body (e.g. 0218A), not defined in the Standards and associated with a classified water body because it is in the same watershed. The third type includes special Segments for Oyster Water Use (e.g. 2421OW) and Beach Watch Use (e.g. 2481CB) special areas. The segment name and description follow SegID.

AU_ID: Identifies the assessment unit (AU_ID, six or seven digits, e.g., 0101A_01) and describes the location of the specific area within a classified or unclassified water body for which one or more water quality standards are not met.

Parameter(s): Pollutants or water quality conditions that assessment procedures indicate do not meet assigned water quality standards or screening levels

Level of Concern: CN - Concern for near-nonattainment of the TSWQS based on numeric criteria CS - Concern for water quality based on screening levels

SEG ID: 0101 Canadian River Below Lake Meredith From the Oklahoma State Line in Hemphill County to Sanford Dam in Hutchinson County

Parameter(s) Level of Concern Ammonia in water CS 0101_03 From the confluence with White Deer Creek upstream to the confluence with Dixon Creek east of Borger 0101_04 From the confluence with Dixon Creek upstream to Sanford Dam in Hutchinson County Parameter(s) Level of Concern Chlorophyll-a in water CS 0101_04 From the confluence with Dixon Creek upstream to Sanford Dam in Hutchinson County Parameter(s) Level of Concern Depressed dissolved oxygen in water CS 0101_04 From the confluence with Dixon Creek upstream to Sanford Dam in Hutchinson County Parameter(s) Level of Concern Nitrate in water CS 0101_03 From the confluence with White Deer Creek upstream to the confluence with Dixon Creek east of Borger

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2020 Texas Integrated Report - Water Bodies with Concerns for Use Attainment and Screening Levels

SEG ID: 1434 Colorado River above La Grange From a point 100 meters (110 yards) downstream of SH 71 at La Grange in Fayette County to a point 100 meters (110 yards) upstream of FM 969 near Utley in Bastrop County Parameter(s) Level of Concern Nitrate in water CS 1434_01 From a point 100 m downstream of SH 71 upstream to the Southern Pacific Railroad crossing 1434_02 Southern-Pacific RR upstream to the confluence of Reeds Creek west of Smithville 1434_03 From the confluence of Reeds Creek west of Smithville upstream to the end of segment Parameter(s) Level of Concern Total Phosphorus in water CS 1434_01 From a point 100 m downstream of SH 71 upstream to the Southern Pacific Railroad crossing 1434_02 Southern-Pacific RR upstream to the confluence of Reeds Creek west of Smithville 1434_03 From the confluence of Reeds Creek west of Smithville upstream to the end of segment

SEG ID:1434B Cedar Creek Perennial stream from the confluence with the Colorado River upstream to the confluence of an unnamed tributary at FM 525 in Bastrop County Parameter(s) Level of Concern Bacteria in water (Recreation Use) CN 1434B_01 Perennial stream from the confluence with the Colorado River upstream to the confluence of an unnamed tributary at FM 525 in Bastrop County Parameter(s) Level of Concern Depressed dissolved oxygen in water CS 1434B_01 Perennial stream from the confluence with the Colorado River upstream to the confluence of an unnamed tributary at FM 525 in Bastrop County

SEG ID:1434D Wilbarger Creek Wilbarger Creek from the confluence of the Colorado River at Hemphill Bend in Bastrop County upstream to Schultz lane east of Pflugerville Heights in Travis County Parameter(s) Level of Concern Bacteria in water (Recreation Use) CN 1434D_01 From the confluence with the Colorado River at Hemphill Bend in Bastrop County upstream to the confluence with Cottonwood Creek 1434D_02 From the confluence with Cottonwood Creek upstream to Schultz lane east of Pflugerville Heights in Travis County Parameter(s) Level of Concern Nitrate in water CS 1434D_02 From the confluence with Cottonwood Creek upstream to Schultz lane east of Pflugerville Heights in Travis County

AR Item 42, Page 005 May 12, 2020 Page 150 of 196

2020 Texas Integrated Report - Texas 303(d) List (Category 5)

As required under Sections 303(d) and 305(b) of the federal Clean Water Act, this list identifies the water bodies in or bordering Texas for which effluent limitations are not stringent enough to implement water quality standards, and for which the associated pollutants are suitable for measurement by maximum daily load.

In addition, the TCEQ also develops a schedule identifying Total Maximum Daily Loads (TMDLs) that will be initiated in the next two years for priority impaired waters. Issuance of permits to discharge into 303(d)-listed water bodies is described in the TCEQ regulatory guidance document Procedures to Implement the Texas Surface Water Quality Standards (June 2010, RG-194).

Impairments are limited to the geographic area described by the Assessment Unit and identified with a six or seven-digit AU_ID. A management strategy will be assigned to each impairment. Specific strategies may inlcude TMDL development, water quality standards evaluation, or additional monitoring.

Explanation of Column Headings

SegID and Name: The unique identifier (SegID), segment name, and location of the water body. Items may be one of three types of numbers for SegID. The first type is a classified segment number (4 digits, e.g. 0218), as defined in the Texas Surface Water Quality Standards. The second type is an unclassified water body (e.g. 0218A), not defined in the Standards and associated with a classified water body because it is in the same watershed. The third type includes special Segments for Oyster Water Use (e.g. 2421OW) and Beach Watch Use (e.g. 2481CB) special areas. The segment name and description follow SegID.

AU_ID: Identifies the assessment unit (AU_ID, six or seven digits, e.g., 0101A_01) and describes the location of the specific area within a classified or unclassified water body for which one or more water quality standards are not met.

Parameter(s): Pollutants or water quality conditions that assessment procedures indicate do not meet assigned water quality standards.

Category: One of three subcategories assigned to each impaired parameter to provide information about water quality status and management activities on that water body. The categories are defined below:

Category 5: The water body does not meet applicable water quality standards or is threatened for one or more designated uses by one or more pollutants. Category 5a - TMDLs are underway, scheduled, or will be scheduled for one or more parameters. Category 5b - A review of the standards for one or more parameters will be conducted before a management strategy is selected, including the possible revision to the TSWQS. Category 5c - Additional data or information will be collected and/or evaluated for one or more parameters before a management strategy is selected.

Year Segment First Listed The initial assessment year the pollutant or water quality condition in this water body (Segment, not specifically the year for each AU_ID) did not meet water quality standards.

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2020 Texas Integrated Report - Texas 303(d) List (Category 5)

SegID: 1425 O. C. Fisher Lake From San Angelo Dam in Tom Green County up to normal pool elevation of 1908 feet (impounds North Concho River) Impairment Description(s) Category Year Segment First Listed Chloride in water 5c 2002 1425_01 From San Angelo Dam in Tom Green County up to normal pool elevation of 1908 feet (impounds North Concho River) Impairment Description(s) Category Year Segment First Listed Total dissolved solids in water 5c 2014 1425_01 From San Angelo Dam in Tom Green County up to normal pool elevation of 1908 feet (impounds North Concho River)

SegID: 1427A Slaughter Creek Intermittent stream with perennial pools from the confluence with Onion Creek to above US 290 west of Austin Impairment Description(s) Category Year Segment First Listed Impaired macrobenthic community in water 5b 2002 1427A_01 Intermittent stream with perennial pools from the confluence with Onion Creek to above US 290 west of Austin

SegID: 1429C Waller Creek From the confluence of Town Lake in central Austin in Travis County to the upstream portion of the stream in north Austin in Travis County Impairment Description(s) Category Year Segment First Listed Bacteria in water (Recreation Use) 5c 2004 1429C_01 From the confluence with Town Lake to East MLK Blvd. Impairment Description(s) Category Year Segment First Listed Impaired macrobenthic community in water 5c 2002 1429C_01 From the confluence with Town Lake to East MLK Blvd.

SegID: 1433 O. H. Ivie Reservoir From S. W. Freese Dam to a point 3.7 km (2.3 mi) downstream of the confluence of Mustang Creek on the Colorado River Arm and to a point 2.0 km (1.2 mi) upstream of the confluence of Fuzzy Creek on the Concho River Arm, up to the conservation pool level of Impairment Description(s) Category Year Segment First Listed Excessive algal growth in water 5c 2020 1433_01 Main pool near dam 1433_02 Concho River arm 1433_03 Colorado River arm 1433_04 Remainder of reservoir

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2020 Texas Integrated Report - Texas 303(d) List (Category 5)

SegID: 1434G Alum Creek From the confluence with the Colorado River in Bastrop County upstream to the headwaters near US 290 approximately 3.5 km southwest of McDade in Bastrop County Impairment Description(s) Category Year Segment First Listed Bacteria in water (Recreation Use) 5c 2020 1434G_01 From the confluence with the Colorado River in Bastrop County upstream to the headwaters near US 290 approximately 3.5 km southwest of McDade in Bastrop County

SegID: 1501 Tres Palacios Creek Tidal From the confluence with Tres Palacios Bay in Matagorda County to a point 1.6 km (1.0 mi) upstream of the confluence of Wilson Creek in Matagorda County Impairment Description(s) Category Year Segment First Listed Depressed dissolved oxygen in water 5b 1999 1501_01 From the confluence with Willow Dam Creek at Tres Palacios Bay/Turtle Bay upstream to a point 1.6 km (1.0 mi) upstream of the confluence of Wilson Creek in Matagorda County

SegID: 1602 Lavaca River Above Tidal From a point 8.6 km (5.3 mi) downstream of US 59 in Jackson County to the confluence of Campbell Branch west of Hallettsville in Lavaca County Impairment Description(s) Category Year Segment First Listed Bacteria in water (Recreation Use) 5a 2008 1602_02 From the confluence of Beard Branch upstream to the upper end of segment at the confluence of Campbell Branch in Hallettsville. 1602_03 Lower portion of segment from confluence with NHD RC 12100101002463 south of Edna in Jackson County upstream to confluence with Beard Branch

SegID: 1602B Rocky Creek Perennial stream from the confluence with the Lavaca River upstream to 2.9 km upstream of County Rd 364 north west of the City of Shiner Impairment Description(s) Category Year Segment First Listed Bacteria in water (Recreation Use) 5a 2014 1602B_01 From the confluence of Lavaca River upstream to confluence of Ponton Creek

SegID: 1602C Lavaca River Above Campbell Branch From the confluence of Campbell Branch in Hallettsville to approximately 3.4 mi upstream of SH 95 in Lavaca Co. Impairment Description(s) Category Year Segment First Listed Depressed dissolved oxygen in water 5b 2004 1602C_01 From confluence of Campbell Branch in Hallettsville upstream to the confluence of West Prong Lavaca River 1602C_02 From confluence of West Prong Lavaca River to the headwaters approximately 6.5 km upstream of TX Hwy 95 in the City of Moulton

AR Item 42, Page 008 May 12, 2020 Page 83 of 115

Appendix Item 17

2022 Texas Integrated Report - Assessment Results for Basin 14 - Colorado River Explanation of Column Headings

SEGID: The unique identifier (SegID), segment name, and location of the water body. Items may be one of three types of numbers for SegID. The first type is a classified segment number (4 digits, e.g., 0218), as defined in the Texas Surface Water Quality Standards. The second type is an unclassified water body (e.g., 0218A), not defined in the Standards and associated with a classified water body because it is in the same watershed. The third type includes special Segments for Oyster Water Use (e.g., 2421OW) and Beach Watch Use (e.g., 2481CB) special areas. The segment name and description follow SegID.

AU ID: Identifies the assessment unit (AU_ID, six or seven digits, e.g., 0101A_01) and describes the location of the specific area within a classified or unclassified water body for which one or more water quality standards are not met.

Start Date: The start date of the period of record data for this method was selected; the official 2022 period of record is from 12/1/2013 to 11/30/2020. In some cases it may be necessary to extend the period of record back 10 years (12/1/2010) to select more data, according to assessment guidance.

End Date: The end date of the period of record data for this method was selected; the official 2022 period of record dates are 12/1/2013 to 11/30/2020. In some cases more recently collected data than 12/01/2020 can be included, if available

#Data Assessed: Number of samples assessed some data are averaged, as with profile data, some are eliminated because criteria do not apply during certain conditions such a s low flow. Mean Data Assessed: Mean of samples assessed includes averaged methods like chronic criteria as well as geometric mean calculations for bacteria. # Exceedances: Number of samples that exceed criteria for single sample, or binomial, methods (not averaged data). Mean Exceedances: Mean of the samples that exceeded criteria for the single sample, or binomial, methods (not averaged data).

Criteria: Value that the data is compared to determine the level of support; Note: for acute metals in water, each value is compared to a calculated criterion and not all criteria could be reported here, only the minimum in the range of criteria calculated are included.

DS Qual: Dataset Qualifier - indicates characteristics of the methods or dataset used in the assessment: AD: Adequate Data (10 or more samples). LD: Limited Data (less than 9, greater than 3). ID: Inadequate Data (less than 4). JQ: Level of support is based on judgment of the assessor. SM: This assessment method is superseded by another method. TR: Temporally Not Representative, used with NA. SR: Spatially Not Representative, used with NA. OE: Other information than ambient samples evaluated. OS: Assessment area outside state boundaries.

LOS: Level of support for this use, method, assessment parameter: FS: Fully Supporting. NC: No Concern. NA: Not Assessed. NS: Nonsupport. CS: Screening Level Concern. CN: Use Concern.

CF: Carry Forward indicates that the Integrated level of support of CS, CN, or NS was carried forward from a previous assessment due to inadequate data for this method in this assessment.

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Int LOS: Integrated level of support. This is the overall level of support for this use, method, parameter group, which could be different from the LOS (described above) due to carry forward information or other types of changes. New Code added in 2010: PI = Pending Issue

TCEQ Cause: This is the impairment description (e.g., bacteria, depressed dissolved oxygen, etc.).

Cat: Category 3: There is insufficient or unreliable available data and/or information to make a use support determination. Category 4: Available data and/or information indicate that at least one designated use is not being supported or is threatened, but a TMDL is not needed. Category 4a: A state-developed TMDL has been approved by EPA or a TMDL has been established by EPA for any water-pollutant combination. Category 4b: Other required control measures are expected to result in the attainment of an applicable water quality standard in a reasonable period of time. Category 4c: The impairment or threat is not caused by a pollutant. Category 5: Available data and/or information indicate that at least one designated use is not being supported or is threatened, and a TMDL is needed. Category 5a: A TMDL is underway, scheduled, or will be scheduled. Category 5b: A review of the standards for the water body will be conducted before a management strategy is selected. Category 5c: Additional data and information will be collected or evaluated before a management strategy is selected. Category 5n: Water body does not meet its applicable Chl a criterion, but additional study is needed to verify whether exceedance is associated with causal nutrient parameters or impacts to response variables.

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Seg ID: 1433 - O. H. Ivie Reservoir AU ID: 1433_02 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS High pH pH 12/01/13 11/30/20 9 12 . 0 . AD FS N FS Low pH pH 12/01/13 11/30/20 6.5 12 . 0 . AD FS N FS General Use Nutrient Reservoir Criteria Nutrients 12/01/13 11/30/20 . 0 . . . AD FS N FS Water Temperature Water temperature 12/01/13 11/30/20 33.9 13 . 0 . AD FS N FS

Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 12 2.47 0 . LD NC N NC

Seg ID: 1433 - O. H. Ivie Reservoir AU ID: 1433_03 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS Dissolved Oxygen grab minimum Dissolved oxygen Grab 12/01/13 11/30/20 3 13 . 0 . AD FS N FS Aquatic Life Use Dissolved Oxygen grab screening level Dissolved oxygen Grab 12/01/13 11/30/20 5 13 . 3 4.85 AD CS N CS Depressed dissolved oxygen in water

Domestic Water Supply Use Surface Water HH criteria for PWS average Nitrate 12/01/13 11/30/20 10 38 0.32 0 . AD FS N FS

High pH pH 12/01/13 11/30/20 9 12 . 0 . AD FS N FS Low pH pH 12/01/13 11/30/20 6.5 12 . 0 . AD FS N FS General Use Nutrient Reservoir Criteria Nutrients 12/01/13 11/30/20 . 0 . . . AD FS N FS Water Temperature Water temperature 12/01/13 11/30/20 33.9 13 . 0 . AD FS N FS

Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 12 1.24 0 . LD NC N NC

Seg ID: 1433 - O. H. Ivie Reservoir AU ID: 1433_04 Start End #Data Mean Data Mean DS Int TCEQ Use Method Parameter Criteria #Exceedances LOS CF Cat Date Date Assessed Assessed Exceedances Qualifier LOS Cause Domestic Water Supply Use Surface Water HH criteria for PWS average Nitrate 12/01/13 11/30/20 10 38 0.32 0 . AD FS N FS

General Use Nutrient Reservoir Criteria Nutrients 12/01/13 11/30/20 . 0 . . . AD FS N FS

Seg ID: 1434 - Colorado River above La Grange AU ID: 1434_01 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS Dissolved Oxygen grab minimum Dissolved oxygen Grab 12/01/13 11/30/20 4 40 . 0 . AD FS N FS Aquatic Life Use Dissolved Oxygen grab screening level Dissolved oxygen Grab 12/01/13 11/30/20 6 40 . 0 . AD NC N NC

Domestic Water Supply Use Surface Water HH criteria for PWS average Nitrate 12/01/13 11/30/20 10 113 4.24 0 . AD FS N FS

Total dissolved solids 12/01/13 11/30/20 500 119 416.56 0 . AD FS N FS Dissolved Solids Sulfate 12/01/13 11/30/20 100 117 62.44 0 . AD FS N FS Chloride 12/01/13 11/30/20 100 118 49.32 0 . AD FS N FS High pH pH 12/01/13 11/30/20 9 40 . 0 . AD FS N FS Low pH pH 12/01/13 11/30/20 6.5 40 . 0 . AD FS N FS General Use Total phosphorus 12/01/13 11/30/20 0.69 40 . 12 0.9 AD CS N CS Total Phosphorus in water Nitrate 12/01/13 11/30/20 1.95 38 . 34 3.7 AD CS N CS Nitrate in water Nutrient Screening Levels Chlorophyll-a 12/01/13 11/30/20 14.1 39 . 7 79.26 AD NC N NC Ammonia 12/01/13 11/30/20 0.33 40 . 0 . AD NC N NC Water Temperature Water temperature 12/01/13 11/30/20 35 40 . 0 . AD FS N FS

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Seg ID: 1434 - Colorado River above La Grange AU ID: 1434_01 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 40 61.26 0 . AD FS N FS

Seg ID: 1434 - Colorado River above La Grange AU ID: 1434_02 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS Dissolved Oxygen grab minimum Dissolved oxygen Grab 12/01/13 11/30/20 4 40 . 0 . AD FS N FS Aquatic Life Use Dissolved Oxygen grab screening level Dissolved oxygen Grab 12/01/13 11/30/20 6 40 . 0 . AD NC N NC

Domestic Water Supply Use Surface Water HH criteria for PWS average Nitrate 12/01/13 11/30/20 10 113 4.24 0 . AD FS N FS

Total dissolved solids 12/01/13 11/30/20 500 119 416.56 0 . AD FS N FS Dissolved Solids Sulfate 12/01/13 11/30/20 100 117 62.44 0 . AD FS N FS Chloride 12/01/13 11/30/20 100 118 49.32 0 . AD FS N FS High pH pH 12/01/13 11/30/20 9 40 . 0 . AD FS N FS Low pH pH 12/01/13 11/30/20 6.5 40 . 0 . AD FS N FS General Use Total phosphorus 12/01/13 11/30/20 0.69 40 . 17 1.01 AD CS N CS Total Phosphorus in water Nitrate 12/01/13 11/30/20 1.95 38 . 34 4.57 AD CS N CS Nitrate in water Nutrient Screening Levels Chlorophyll-a 12/01/13 11/30/20 14.1 40 . 2 51.1 AD NC N NC Ammonia 12/01/13 11/30/20 0.33 39 . 0 . AD NC N NC Water Temperature Water temperature 12/01/13 11/30/20 35 40 . 0 . AD FS N FS

Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 40 60.78 0 . AD FS N FS

Seg ID: 1434 - Colorado River above La Grange AU ID: 1434_03 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS Dissolved Oxygen grab minimum Dissolved oxygen Grab 12/01/13 11/30/20 4 39 . 0 . AD FS N FS Aquatic Life Use Dissolved Oxygen grab screening level Dissolved oxygen Grab 12/01/13 11/30/20 6 39 . 0 . AD NC N NC

Domestic Water Supply Use Surface Water HH criteria for PWS average Nitrate 12/01/13 11/30/20 10 113 4.24 0 . AD FS N FS

Total dissolved solids 12/01/13 11/30/20 500 119 416.56 0 . AD FS N FS Dissolved Solids Sulfate 12/01/13 11/30/20 100 117 62.44 0 . AD FS N FS Chloride 12/01/13 11/30/20 100 118 49.32 0 . AD FS N FS High pH pH 12/01/13 11/30/20 9 39 . 0 . AD FS N FS Low pH pH 12/01/13 11/30/20 6.5 39 . 0 . AD FS N FS General Use Total phosphorus 12/01/13 11/30/20 0.69 39 . 19 1.13 AD CS N CS Total Phosphorus in water Nitrate 12/01/13 11/30/20 1.95 37 . 34 5.4 AD CS N CS Nitrate in water Nutrient Screening Levels Chlorophyll-a 12/01/13 11/30/20 14.1 39 . 2 19.4 AD NC N NC Ammonia 12/01/13 11/30/20 0.33 39 . 0 . AD NC N NC Water Temperature Water temperature 12/01/13 11/30/20 35 39 . 0 . AD FS N FS

Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 39 72.79 0 . AD FS N FS

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Seg ID: 1434B - Cedar Creek AU ID: 1434B_01 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS Aquatic Life Use Dissolved Oxygen grab screening level Dissolved oxygen Grab 12/01/13 11/30/20 5 0 . . . ID NA Y CS Depressed dissolved oxygen in water

Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 0 . . . ID NA Y CN Bacteria in water

Seg ID: 1434C - Lake Bastrop AU ID: 1434C_02 Start End #Data Mean Data Mean DS Int TCEQ Use Method Parameter Criteria #Exceedances LOS CF Cat Date Date Assessed Assessed Exceedances Qualifier LOS Cause Dissolved Oxygen grab minimum Dissolved oxygen Grab 12/01/13 11/30/20 3 42 . 0 . AD FS N FS Aquatic Life Use Dissolved Oxygen grab screening level Dissolved oxygen Grab 12/01/13 11/30/20 5 42 . 1 4.49 AD NC N NC

Total phosphorus 12/01/13 11/30/20 0.2 42 . 3 0.85 JQ NA N NA Nitrate 12/01/13 11/30/20 0.37 41 . 0 . JQ NA N NA General Use Nutrient Screening Levels Chlorophyll-a 12/01/13 11/30/20 26.7 42 . 7 41.11 JQ NA N NA Ammonia 12/01/13 11/30/20 0.11 41 . 2 0.45 JQ NA N NA

Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 41 2.95 0 . AD FS N FS

Seg ID: 1434D - Wilbarger Creek AU ID: 1434D_01 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS Dissolved Oxygen grab minimum Dissolved oxygen Grab 12/01/13 11/30/20 3 13 . 0 . AD FS N FS Aquatic Life Use Dissolved Oxygen grab screening level Dissolved oxygen Grab 12/01/13 11/30/20 5 13 . 1 4.7 AD NC N NC

Total phosphorus 12/01/13 11/30/20 0.69 14 . 0 . AD NC N NC Nitrate 12/01/13 11/30/20 1.95 13 . 2 3.16 AD NC N NC General Use Nutrient Screening Levels Chlorophyll-a 12/01/13 11/30/20 14.1 14 . 3 105.33 AD NC N NC Ammonia 12/01/13 11/30/20 0.33 14 . 0 . AD NC N NC

Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 8 210.4 1 . LD CN N CN Bacteria in water

Seg ID: 1434D - Wilbarger Creek AU ID: 1434D_02 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS Dissolved Oxygen grab minimum Dissolved oxygen Grab 12/01/13 11/30/20 3 8 . 0 . LD NC N NC Aquatic Life Use Dissolved Oxygen grab screening level Dissolved oxygen Grab 12/01/13 11/30/20 5 8 . 0 . LD NC N NC

Total phosphorus 12/01/13 11/30/20 0.69 10 . 1 0.72 AD NC N NC Nitrate 12/01/13 11/30/20 1.95 11 . 3 5.4 AD NC N NC General Use Nutrient Screening Levels Chlorophyll-a 12/01/13 11/30/20 14.1 11 . 2 23.1 AD NC N NC Ammonia 12/01/13 11/30/20 0.33 11 . 2 0.6 AD NC N NC

Recreation Use Bacteria Geomean E. coli 12/01/13 11/30/20 126 11 157.2 1 . LD CN N CN Bacteria in water

Seg ID: 1434E - Big Sandy Creek AU ID: 1434E_01 Start End #Data Mean Data Mean DS Int Use Method Parameter Criteria #Exceedances LOS CF TCEQ Cause Cat Date Date Assessed Assessed Exceedances Qualifier LOS General Use Nutrient Screening Levels Chlorophyll-a 12/01/13 11/30/20 14.1 0 . . . ID NA Y CS Chlorophyll-a in water AR Item 43, Page 005

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2022 Texas Integrated Report - Water Bodies with Concerns for Use Attainment and Screening Levels Explanation of Column Headings SegID and Name: The unique identifier (SegID) and name of the water body. Items may be one of three types of numbers for SegID. The first type is a classified segment number (4 digits, e.g., 0218), as defined in the Texas Surface Water Quality Standards (TSWQS). The second type is an unclassified water body (e.g., 0218A), not defined in the Standards and associated with a classified water body because it is in the same watershed. The third type includes special Segments for Oyster Water Use (e.g., 2421OW) and Beach Watch Use (e.g., 2481CB) special areas. AU ID: Identifies the assessment unit (AU_ID, six or seven digits, e.g., 0101A_01) and describes the location of the specific area within a classified or unclassified water body for which one or more water quality standards are not met. Parameter(s): Pollutants or water quality conditions that assessment procedures indicate do not meet assigned water quality standards.

Level Of Concern: • CN - Concern for near-nonattainment of the TSWQS based on numeric criteria. • CS - Concern for water quality based on screening levels.

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2022 Texas Integrated Report - Water Bodies with Concerns for Use Attainment and Screening Levels

Level of Segment ID Segment Name AU ID Parameters Concern 1428C_01 CS 1428C_02 CS 1428C Gilleland Creek Nitrate in water 1428C_03 CS 1428C_04 CS 1429C_02 Benzo(a)anthracene in sediment CS 1429C_02 Benzo(a)pyrene in sediment CS 1429C_02 Chrysene in sediment CS 1429C_02 Dibenz(a,h)anthracene in sediment CS 1429C_02 Fish kill in water CN 1429C Waller Creek 1429C_02 Fluoranthene in sediment CS 1429C_02 Lead in sediment CS 1429C_02 Nitrate in water CS 1429C_02 Phenanthrene in sediment CS 1429C_02 Pyrene in sediment CS 1429D_01 Benzo(a)anthracene in sediment CS 1429D_01 Cadmium in sediment CS 1429D_01 Chrysene in sediment CS 1429D_01 Dibenz(a,h)anthracene in sediment CS 1429D East Bouldin Creek 1429D_01 Fluoranthene in sediment CS 1429D_01 Lead in sediment CS 1429D_01 Phenanthrene in sediment CS 1429D_01 Pyrene in sediment CS 1430 Barton Creek 1430_02 Toxicity in sediment CN 1430A Barton Springs 1430A_01 Toxicity in sediment CN 1431_01 Chlorophyll-a in water CS 1431 Mid Pecan Bayou 1431_01 Nitrate in water CS 1431_01 Total Phosphorus in water CS 1432 Upper Pecan Bayou 1432_01 Chlorophyll-a in water CS 1433_02 CS 1433 O. H. Ivie Reservoir Depressed dissolved oxygen in water 1433_03 CS 1434_01 CS 1434 Colorado River above La Grange 1434_02 Nitrate in water CS 1434_03 CS

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2022 Texas Integrated Report - Water Bodies with Concerns for Use Attainment and Screening Levels

Level of Segment ID Segment Name AU ID Parameters Concern 1434_01 CS 1434 Colorado River above La Grange 1434_02 Total Phosphorus in water CS 1434_03 CS 1434B_01 Bacteria in water (Recreation Use) CN 1434B Cedar Creek 1434B_01 Depressed dissolved oxygen in water CS 1434D_01 CN 1434D Wilbarger Creek Bacteria in water (Recreation Use) 1434D_02 CN 1434E Big Sandy Creek 1434E_01 Chlorophyll-a in water CS 1501_01 Chlorophyll-a in water CS 1501 Tres Palacios Creek Tidal 1501_01 Nitrate in water CS 1502 Tres Palacios Creek Above Tidal 1502_03 Depressed dissolved oxygen in water CS 1601C Dry Creek 1601C_01 Depressed dissolved oxygen in water CS 1602B Rocky Creek 1602B_01 Total Phosphorus in water CS 1701 Victoria Barge Canal 1701_01 Chlorophyll-a in water CS 1801 Guadalupe River Tidal 1801_01 Nitrate in water CS 1802 Guadalupe River Below San Antonio River 1802_01 Nitrate in water CS 1803 Guadalupe River Below San Marcos River 1803_01 Nitrate in water CS 1803A_01 Chlorophyll-a in water CS 1803A Elm Creek 1803A_01 Depressed dissolved oxygen in water CS 1803B Sandies Creek 1803B_02 Depressed dissolved oxygen in water CS 1803C_03 Chlorophyll-a in water CS 1803C Peach Creek 1803C_03 Impaired macrobenthic community in water CN 1803C_03 Total Phosphorus in water CS 1804A Geronimo Creek 1804A_01 Nitrate in water CS 1804D Bear Creek 1804D_01 Bacteria in water (Recreation Use) CN 1806_02 CN Impaired fish community in water 1806_12 CN 1806 Guadalupe River Above Canyon Lake 1806_02 CS Impaired habitat in water 1806_12 CS 1806A Camp Meeting Creek 1806A_01 Depressed dissolved oxygen in water CS 1807_01 CS 1807 Coleto Creek Chlorophyll-a in water 1807_02 CS 1808 Lower San Marcos River 1808_01 Bacteria in water (Recreation Use) CN 1810_03 Ammonia in water CS 1810 Plum Creek 1810_03 Fish kill in water CN

AR Item 43, Page 008 July 7, 2022 36 of 48

2022 Texas Integrated Report - Index of Water Quality Impairments General Information:

Category 4: Impairments that are not suitable for a TMDL or for which a TMDL has already been approved. Category 5: Impairments which may be suitable for development of a TMDL (303(d) List).

Explanation of Column Headings:

SegID and Name: The unique identifier (SegID) and name of the water body. Items may be one of three types of numbers for SegID. The first type is a classified segment number (4 digits, e.g., 0218), as defined in the Texas Surface Water Quality Standards (TSWQS). The second type is an unclassified water body (e.g., 0218A), not defined in the Standards and associated with a classified water body because it is in the same watershed. The third type includes special Segments for Oyster Water Use (e.g., 2421OW) and Beach Watch Use (e.g., 2481CB) special areas.

AU ID: Identifies the assessment unit (AU_ID, six or seven digits, e.g., 0101A_01) and describes the location of the specific area within a classified or unclassified water body for which one or more water quality standards are not met.

Parameter(s): Pollutants or water quality conditions that assessment procedures indicate do not meet assigned water quality standards.

Category: One of seven subcategories assigned to each impaired parameter to provide information about water quality status and management activities on that water body. The categories are defined below: Category 4: Available data and/or information indicate that at least one designated use is not being supported or is threatened, but a TMDL is not needed. Category 4a: A state-developed TMDL has been approved by EPA or a TMDL has been established by EPA for any water-pollutant combination. Category 4b: Other required control measures are expected to result in the attainment of an applicable water quality standard in a reasonable period of time. Category 4c: The impairment or threat is not caused by a pollutant. Category 5: Available data and/or information indicate that at least one designated use is not being supported or is threatened, and a TMDL is needed. Category 5a: A TMDL is underway, scheduled, or will be scheduled. Category 5b: A review of the standards for the water body will be conducted before a management strategy is selected. Category 5c: Additional data and information will be collected or evaluated before a management strategy is selected. Category 5n: Water body does not meet its applicable Chl a criterion, but additional study is needed to verify whether exceedance is associated with causal nutrient parameters or impacts to response variables.

Carry Forward: Some previously listed impairments did not have adequate data to re-assess in 2022 and were carried forward from 2020 and remain impaired.

AR Item 43, Page 009 July 7, 2022 1 of 40

2022 Texas Integrated Report - Index of Water Quality Impairments

Segment Carry Segment Name AU ID Parameter Category ID Forward 1428B Walnut Creek 1428B_05 Bacteria in water (Recreation Use) 4a N 1428C_01 Bacteria in water (Recreation Use) 4a N 1428C Gilleland Creek 1428C_03 Bacteria in water (Recreation Use) 4a N 1428C_04 Bacteria in water (Recreation Use) 4a N 1429_01 Excessive algal growth in water 5c N 1429 Lady Bird Lake (formerly Town Lake) 1429_02 Excessive algal growth in water 5c N Bacteria in water (Recreation Use) 5c N 1429C_01 Impaired macrobenthic community in water 5c Y 1429C Waller Creek 1429C_02 Bacteria in water (Recreation Use) 4a N 1429C_03 Bacteria in water (Recreation Use) 4a N Bacteria in water (Recreation Use) 4a Y 1501 Tres Palacios Creek Tidal 1501_01 Depressed dissolved oxygen in water 5b Y 1602_02 Bacteria in water (Recreation Use) 5a N 1602 Lavaca River Above Tidal 1602_03 Bacteria in water (Recreation Use) 4a N 1602B Rocky Creek 1602B_01 Bacteria in water (Recreation Use) 4a N 1602C_01 Depressed dissolved oxygen in water 5c Y 1602C Lavaca River Above Campbell Branch 1602C_02 Depressed dissolved oxygen in water 5c Y 1801 Guadalupe River Tidal 1801_01 Bacteria in water (Recreation Use) 5c N 1803A Elm Creek 1803A_01 Depressed dissolved oxygen in water 5b Y Bacteria in water (Recreation Use) 5b N 1803B_01 Depressed dissolved oxygen in water 5b Y 1803B Sandies Creek Bacteria in water (Recreation Use) 5b Y 1803B_02 Depressed dissolved oxygen in water 5b Y Bacteria in water (Recreation Use) 5b N 1803C_01 Depressed dissolved oxygen in water 5c Y 1803C Peach Creek Bacteria in water (Recreation Use) 5b Y 1803C_03 Depressed dissolved oxygen in water 5c Y 1804A Geronimo Creek 1804A_01 Bacteria in water (Recreation Use) 5c N 1805_01 Mercury in edible tissue 5c N 1805_02 Mercury in edible tissue 5c N 1805 Canyon Lake 1805_03 Mercury in edible tissue 5c N 1805_04 Mercury in edible tissue 5c N 1806 Guadalupe River Above Canyon Lake 1806_08 Bacteria in water (Recreation Use) 5c N 1806A Camp Meeting Creek 1806A_01 Bacteria in water (Recreation Use) 5a N 1806D Quinlan Creek 1806D_01 Bacteria in water (Recreation Use) 4a N 1806E Town Creek 1806E_01 Bacteria in water (Recreation Use) 4a N AR Item 43, Page 010

July 7, 2022 29 of 40 Appendix Item 18 § 307.10. Appendices A-G, 30 TX ADC § 307.10

KeyCite Yellow Flag - Negative Treatment Proposed Regulation

Texas Administrative Code Title 30. Environmental Quality Part 1. Texas Commission on Environmental Quality Chapter 307. Texas Surface Water Quality Standards

30 TAC § 307.10

§ 307.10. Appendices A-G

Effective: September 29, 2022 Currentness

The following appendices are integral components of this chapter of the Texas Surface Water Quality Standards. (1) Appendix A--Site-specific Uses and Criteria for Classified Segments: Figure: 30 TAC § 307.10(1)

© 2024 Thomson Reuters. No claim to original U.S. Government Works. REF Item 1, Page 1 001

§ 307.10. Appendices A-G, 30 TX ADC § 307.10

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§ 307.10. Appendices A-G, 30 TX ADC § 307.10

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§ 307.10. Appendices A-G, 30 TX ADC § 307.10 (3) Appendix C--Segment Descriptions: Figure: 30 TAC §307.10(3)

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§ 307.10. Appendices A-G, 30 TX ADC § 307.10

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§ 307.10. Appendices A-G, 30 TX ADC § 307.10 (4) Appendix D--Site-specific Uses and Criteria for Unclassified Water Bodies: Figure: 30 TAC §307.10(4)

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§ 307.10. Appendices A-G, 30 TX ADC § 307.10

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Automated Certificate of eService This automated certificate of service was created by the efiling system. The filer served this document via email generated by the efiling system on the date and to the persons listed below. The rules governing certificates of service have not changed. Filers must still provide a certificate of service that complies with all applicable rules.

Laura Courtney on behalf of Amanda Cagle Bar No. 783569 laura.courtney@oag.texas.gov Envelope ID: 106432859 Filing Code Description: Brief Requesting Oral Argument Filing Description: Brief of Appellant TCEQ Status as of 10/3/2025 3:11 PM CST

Associated Case Party: Wilbarger Creek Conservation Alliance Name BarNumber Email TimestampSubmitted Status Christopher Smith 24051349 Chris.Smith@smithjolin.com 10/3/2025 3:01:36 PM SENT Becky Jolin 10856200 Becky.Jolin@smithjolin.com 10/3/2025 3:01:36 PM SENT Associated Case Party: Texas Commission on Environmental Quality Name BarNumber Email TimestampSubmitted Status Laura Courtney laura.courtney@oag.texas.gov 10/3/2025 3:01:36 PM SENT Sara Ferris sara.ferris@oag.texas.gov 10/3/2025 3:01:36 PM SENT Amanda Cagle amanda.cagle@oag.texas.gov 10/3/2025 3:01:36 PM SENT Colton Halter colton.halter@oag.texas.gov 10/3/2025 3:01:36 PM SENT