OCR Text |
Show cember 13, 1912, two 20" Jackson Church centrifugal pumps, delivering 25 cf .s. each, began operation, and with additional pumping equipment subsequently installed, continued until June 27, 1942. In 1918, the first improvement leases were approved for an aggregate of 5,000 acres. In July 1918, the Congress appropriated $50,000 for the investigation of a gravity flow system. In 1933, $200,000 was appropriated for drainage. In 1936, Boulder Dam was placed in operation stabilizing the flow of the Colorado River and making clear water available. Whereas earlier the project was faced with problems arising from too much silt in the water, now there was not enough silt to keep the canals sealed and problems of weed, brush, and rodent control were intensified. On August 9, 1937, the Congress appropriated the first funds for the construction of the gravity flow system. On August 6, 1938, construction work was started on the Headgate Rock Dam and control works. In 1942, these structures were completed and the operation was converted to a gravity flow system. The system was enlarged and extended, until now 38,000 acres are in operation. Soils-Physiography The area considered consists of river flood plains gently sloping south, with varying cross gradiants, which are generally characterized by the local occurrence of low swales, old slough channels, and intermittent sand dunes. During recent geological times and prior to river control upstream, the Colorado River flooded the area intermittently, depositing new materials and reworking the valley from side to side. Sediments of various geological origin brought from a wide area within the Colorado River watershed were deposited in varying locations, sequences and thickness, depending upon the vagaries of the stream. |
Source |
Original book: [State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants, United States of America, State of Nevada, State of New Mexico, State of Utah, interveners] : |