25 U.S.C. § 381 : US Code - Section 381: Irrigation lands; regulation of use of water

Search 25 U.S.C. § 381 : US Code - Section 381: Irrigation lands; regulation of use of water

In cases where the use of water for irrigation is necessary to
render the lands within any Indian reservation available for
agricultural purposes, the Secretary of the Interior is authorized
to prescribe such rules and regulations as he may deem necessary to
secure a just and equal distribution thereof among the Indians
residing upon any such reservations; and no other appropriation or
grant of water by any riparian proprietor shall be authorized or
permitted to the damage of any other riparian proprietor.