On October 9, 1924, the 339 individual landowners in the Auxiliary Eastern Canal Irrigation District reorganized as the Roosevelt Water Conservation District (RWCD, or the District). RWCD planned to build a pumping plant and canal, and pay the Salt River Valley Water Users’ Association (Association) $789,000 for the cost of lining the South, Eastern, and Consolidated canals. The Association agreed to divert floodwaters to the District’s pumping plant, and to store water saved by the canal lining project behind Roosevelt Dam until needed by RWCD farmers.

RWCD board of directors entered into a contract with the Jasper-Stacy Construction Company of San Francisco for construction of the project on April 19, 1924. The total amount financed, with interest, came to almost $70 per acre. Construction of the project was to be done in two phases. The first construction period included completion of the District’s Main Pumping Plant and one of two discharge pipes, with installation of four of the six pumping units, so that the plant could be operating at half capacity by the spring of 1925.  Excavation of the Main Canal and laterals would be completed, but they would not be lined until the second phase.

The second construction period, which included some of the more expensive components of the irrigation system, was to begin when half the District was under irrigation. Work to be completed included lining of the Consolidated Canal by the Association (13.62 miles of canal, requiring 3,063,000 square feet of concrete), installation of the remaining two pumping units at the Main Pumping Plant, lining of the Main Canal, development of wells, and construction of two substations and electrical transmission lines.

Construction of the RWCD irrigation works officially began on December 24, 1924. The pumping plant was completed on June 1, ready to deliver water at half capacity, but it was not used until February 1926, due to the delay in canal lining and the low water supply behind Roosevelt Dam. The Main Canal was completed on June 12, 1925, ending the first construction period.  The project was substantially complete by March 1926. On June 25, 1928, the Roosevelt Water Conservation District submitted a Notice of Completion of Work and Proof of Application of Water to Beneficial Use.

The final cost of the project came to $3,750,000, or $90 per acre. That was much higher than had originally been estimated, but a secure water supply had been developed, and District farms were producing citrus and deciduous fruit, lettuce, cantaloupe, alfalfa, short staple Acala cotton, and milo maize. The duty of water was set at 3.2 acre feet per acre, with a water rate of $2.50 per acre foot. In 1926, 13,200 acres — one third of the District — was irrigated; in 1927, 10,000 more acres were brought under cultivation; by spring of 1928, the RWCD was almost fully developed, with crops planted on 38,5000 acres.