Pacific Southwest Water Plan August 1963

Document: "Pacific Southwest Water Plan- Corrected to 8/19" Chapter II, August 19, 1964, page 3refused to approve the Compact until December 1928 when it passed the Boulder Canyon Project Act. This Act approved the Compact. However, the Act would not be effective except upon condition that all seven Basin States ratify the compact or, if all States failed to ratify the Compact within six months from date of passage of the Act then, until six of the States, including the State of California, should ratify the Compact, and further until the State of California, by act of its legislature, should agree with the United States and for the benefit of the other Basin States that is aggregate annual consumptive use of water from the Colorado River should not exceed 4,400,000 acre-feet per year, plus not more than one-half of any excess or surplus waters unapportioned by the Compact. In 1929, the legislature of the State of California passed a bill limiting its uses as aforesaid. Thereafter, on June 25, 1929, the President declared the Boulder Canyon Project Act to have become effective. The Act, among other things, authorized the construction of Hoover Dam and the All-American Canal. Hoover Dam was constructed between 1930 and 1935, and brought the first control to the Colorado River. The All-American Canal, so called because it would flow entirely within the United States, was constructed between 1934 and 1942, thus ending diversions through Mexican territory. The Imperial Diversion Dam, constructed during this period, supplanted the Laguna Diversion Dam, built in 1909, and delivered water to both the Yuma and Imperial Valley irrigated areas. Other surface-water control works built during this period include Davis Dam on the Colorado River, which, in conjunction with Parker Dam, the forebay for the Metropolitan Water District pumping system, helps to control floods along the river and reregulate the riverflow for benefit of downstream irrigation and Mexican Treaty commitments. The combined works, named the Parker-Davis Project, also produce electrical energy which is distributed in the Pacific Southwest. Construction of Headgate Rock Diversion Dam was completed in 1941, which, with a connecting canal, made possible a dependable and increased water supply to lands of the Colorado River Indian Reservation and replaced the pumping system which had been used for many years to obtain water from the Colorado River. The Palo Verde Diversion Dam was subsequently constructed to facilitate diversions to the Palo Verde Irrigation District. Long before the time of Christ, irrigation was extensively practiced by ancient Indian civilizations in central Arizona. Drawing No. 344-314-111 is a map of the ancient canal system of the Hohokam (those who are gone) Indians as it existed about 1100 A. D. when the system was abandoned and this civilization disappeared. When the early Spanish explorers arrived in the area in the 16th century they found a later Indian culture occupying and irrigating the same lands. It is believed by many that drouth conditions forced the ancient civilization to abandon its lands and move away. II-3Epson Perfection 4870 Photo, 400 dpi, 8 bit, 1,802,295 byte