43 U.S.C. § 390dd

Except as provided in section 390ii of this title , irrigation water may not be delivered to— (1) a qualified recipient for use in the irrigation of lands owned by such qualified recipient in excess of nine hundred and sixty acres of class I lands or the equivalent thereof; or (2) a limited recipient for the use in the irrigation of lands owned by such limited recipient in excess of six hundred and forty acres of class I lands or the equivalent thereof; whether situated in one or more districts.