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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 on the Colorado River include Davis Dam and Parker Dam, the forebay for the Metropolitan Water District pumping system. These dams help 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 drought conditions or poor irrigation practices forced the ancient civilization to abandon its lands and move away. Although various Indian tribes had been irrigating lands along rivers and streams in Arizona for many centuries, the first white settlers began diversions in the mid-1800's. Throughout the remainder of the century, canals were extended and new canals built that increased the irrigated acreage. In the 1890's, alternating severe flood and drought conditions beset the Salt River Valley. The tenacity and determination of the people resulted in the formation of an organization pledged to rebuilding its agricultural enterprise. Following enactment of the Reclamation Act of 1902, Arizona, still a territory, immediately moved forward. Construction of the Salt River II-3Epson Perfection 4870 Photo, 400 dpi, 8 bit, 14,131,200 byte