Central Arizona Project

The Bureau of Reclamation’s Central Arizona Project (CAP) collection presents results of the extensive cultural resource investigations conducted during the planning, construction, and maintenance of the project’s water delivery systems and associated infrastructure. The wide scope and expansive scale of CAP archaeology represent an impressive and now integral contribution to Southwestern archaeology, and much of the work changed and challenged many conceptions of Arizona’s prehistory. The collection’s materials are organized according to the CAP’s water delivery systems and other structures. Within each of these delivery system collections, materials are further divided into archaeological projects and tasks that were conducted to investigate cultural resources

The CAP is a multipurpose water resource development and management project that provides irrigation, municipal and industrial water, power, flood control, outdoor recreation, environmental enhancement and sediment control. The project also provides delivery of Tribal homeland water, partial settlement of Indian water rights claims, and economic benefits accruing from the leasing of Indian agricultural water rights to municipal entities. Water is provided to lands in Maricopa, Pinal and Pima counties, and to several communities, including the metropolitan areas of Phoenix and Tucson. Authorization also was included for development of facilities to deliver water to Catron, Hidalgo, and Grant Counties in New Mexico. In addition to water delivery systems, the CAP includes power generation infrastructure, principally participation in the Navajo Generation Station and a transmission system to supply power to pumping plants and check structures of the Hayden-Rhodes, Fannin-McFarland and Tucson aqueducts

For administration and construction purposes, the CAP was divided into the Granite Reef, Orme, Salt-Gila, Gila River, Tucson, and the Indian and Non-Indian Distribution divisions. During project construction, the Orme Division was re-formulated and renamed the Regulatory Storage Division; it includes New Waddell Dam and Camp Dyer Diversion Dam. Upon completion, the Granite Reef Division was re-named the Hayden-Rhodes Aqueduct, and the Salt-Gila Division was renamed the Fannin-McFarland Aqueduct.

The CAP was authorized by the Colorado River Basin Project Act of 1968. Construction of the project began in 1973 with the award of a contract for the Havasu Intake Channel Dike and excavation for the Havasu Pumping Plant (Mark Wilmer Pumping Plant) on the shores of Lake Havasu. Construction of the other project features followed. The backbone aqueduct system, which runs about 336 miles from Lake Havasu to a terminus southwest of Tucson, was declared substantially complete in 1993. The new and modified dams constructed as part of the project were declared substantially complete in 1994. All of the non-Indian agricultural water distribution systems were completed in the late 1980s, as were most of the municipal water delivery systems. Several Indian distribution systems are either under construction or remain to be built; it is estimated that full development of these systems could require another 20 years or longer.

When authorized, the plan included the construction of Hooker Dam and Buttes Dam on the Gila River to provide conservation storage, flood and sediment control, and recreation opportunities, and the construction of Orme Dam at the junction of the Salt and Verde Rivers to provide flood protection and water conservation. None of these facilities were built. Although authorized, Buttes Dam and Hooker Dam on the Gila River (in New Mexico) and Charleston Dam on the San Pedro River were not constructed because of cost considerations, a lack of demand for the water, lack of repayment capability by the users, and environmental constraints. To fulfill the authorized functions of Orme Dam, Plan 6 was developed. Plan 6 is the Regulatory Storage Division of the project and includes New Waddell Dam and Camp Dryer Diversion Dam located on the Agua Fria River, a tributary of the Gila River, and a modified Roosevelt and Stewart Mountain dams on the Salt River. These two dams predate the project and have been modified for safety and increased storage capacity.