25 C.F.R. § 137.1
The engineering report dealt with in section 1 of the act of June 7, 1924 (43 Stat. 475) and other available records show that the storage capacity of the San Carlos reservoir created by the Coolidge Dam and the water supply therefor over a period of years will provide for the irrigation of only 80,000 acres of lands in Indian and public or private ownership within the San Carlos irrigation project, the balance of the water supply needed for the additional 20,000 acres of the project to be provided for by recaptured and return flow water and by means of pumping the underground supply. The cost of providing the proposed supply and of operating the works for this latter acreage to be equally distributed over the entire 100,000 acres of the project regardless of where the works are placed and operated.
25 C.F.R. § 137.1