The $52 million Tri-Dam project would mainly be financed by leasing hydro-power rights at these dams to Pacific Gas & Electric Company (PG&E) for a 50-year period. Like Melones, the Tri-Dam Project would be jointly owned and operated by the two districts. After almost ten years of construction, Donnells and Beardsley Dam were completed in 1957, and Tulloch Dam completed in 1958. The three dams combined could store , more than tripling the water storage capacity on the Stanislaus River, and increased the reliable annual supply to almost . These were the last major water projects completed on the river until 1972, when work began on the federal New Melones Dam which would replace and submerge the original 1926 Melones Dam.