BCP - Coachella Canal Rehabilitation and Betterment
General
Experience in operating the irrigation facilities serving the Coachella Valley has revealed several deficiencies inherent in the canal and distribution system as constructed. The most serious were the lack of regulatory storage reservoirs along the main canal; lack of fine control on water movement through the main canal due to the distance between check structures and inability to reach those structures under certain conditions; the inability to get designed deliveries through farm turnout structures; and unexpected operating problems caused by accumulation of moss and debris in the main canal.
History
The Boulder Canyon Project Act of December 21, 1928, authorized construction of an All-American Canal system to deliver irrigation water to Imperial and Coachella Valleys, California, and a distribution system in Coachella Valley. Construction of the underground distribution system, the first of its size and magnitude constructed by the Bureau of Reclamation, was completed in 1954. The distribution system was transferred to the CVWD (Coachella Valley Water District) for operation and maintenance on a section-by-section basis as each construction unit was completed. Formal transfer of the system was made in July 1954. The Colorado River Basin Salinity Control Project legislation provided for the concrete lining of the initial 49 miles of Coachella Canal to reduce seepage losses. The concrete lining work was completed in 1980, and operation and maintenance was transferred to the district on November 1, 1981. The facilities being operated and maintained by the district include 74 miles of the Coachella Canal and appurtenant flood control works, and an underground distribution system capable of serving about 78,530 irrigable acres. The system can serve about 70,000 acres; the remaining 8,530 acres are primarily Indian lands to which extensions and turnouts are being constructed by the district under contract of October 14, 1958, entered into with the Secretary of the Interior (Bureau of Indian Affairs) pursuant to the act of August 28, 1958 (72 Stat. 968). At the end of calendar year 1982, about 57,000 acres in the valley had been developed and were receiving Colorado River water through the federally constructed system. Several hundred additional acres under the system are irrigated entirely with ground water from private wells.
Construction
The R&B work was begun by the district in January 1964 and was essentially completed in 1977. Benefits to the district are: (1) reduced operation and maintenance costs, (2) more reliable water service, (3) water conservation, (4) increased returns from crop production, and (5) flood control. The recreation facilities at Lake Cahuilla were developed by the Riverside County Department of Parks under a lease agreement with the CVWD. Picnicking, swimming, camping, boating, and fishing for trout, bass, and catfish are popular activities. For specific information about recreation activities at Lake Cahuilla, click on the name below: http://www.recreation.gov/detail.cfm?ID=18
Plan
The general nature and purpose of the rehabilitation and betterment (R&B) program was to install a supervisory remote control and telemetering system for operating the canal and distribution system; to construct a terminal reservoir; dikes No. 2 and 4, and Avenue 64 Evacuation Channel; and to install traveling screens, a new check gate, and rehabilitate an existing check gate in the canal. Dike No. 2 extends from near Avenue 58 to the north end of Coral Reef near Avenue 59. Dike No. 4 extends from the south end of Coral Reef from below Avenue 59 to below Avenue 65. These dikes protect the area from floodwaters discharged from the upstream canyons and provide detention reservoirs to store the floodwaters. These excess flows are released through the Avenue 64 Evacuation Channel, which extends about 6 miles to the Whitewater Storm Channel. The terminal reservoir, Lake Cahuilla, at the end of the Coachella Canal on the west side of the valley, provides regulatory storage of irrigation water and impounds storm waters from the mountains to the west. It also serves as a temporary reservoir for La Quinta area floodwaters. The lake is 3,960 feet long by 1,980 feet wide and 11 to 12 feet deep. It is lined with soil cement to prevent seepage. The entire distribution system and the Coachella Main Canal are operated and maintained by the CVWD.
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