Historic American Engineering Record: Coolidge Dam, Pinal County, Arizona

Author(s): David M. Introcaso

Year: 1986


Historic American Engineering Record (HAER) No. AZ-7 presents a written historical summary and relevant historical documentation about the construction and use of the Coolidge Dam, which impounds water along the Gila River to form the San Carlos Reservoir 30 miles southwest of Globe, Arizona. It also contains a summary of Gila River water usage and conflicts over water access, from native Pima and Maricopa water use to Historic era, multi-community uses. The report contains a narrative description, photographs, drawings, and maps.

Coolidge dam is the principal water storage and regulation feature for the San Carlos Irrigation Project and San Carlos Drainage District water supply system. The dam stores Gila River water in the San Carlos Reservoir and helps to allocate that water to users. It provides water to the San Carlos Irrigation Project that serves the Gila River Indian Community. Additionally, it provides water to the San Carlos Irrigation and Drainage District that serves anglo and other non-Indian communities in the lower reaches of the Gila River valley and surroundings.

The history surrounding the development of water resources on the Gila River is not the typical narrative of reclaiming public lands for settlement. Instead, it encompasses the story of native communities increasing loss of water access, conflicts over water allocation and use, and the restoration of water access to native peoples.

During prehistory and the Historic period, indigenous communities who were affiliated with Historic Pima and Maricopa populations relied on the perennial flow of the Gila River to support a robust agricultural economy. In the mid 19th century, the sustained incursion of anglo settlers, principally American, began to strain the Gila's water resources and created competing interests. Unfortunately, the limited natural flow of the Gila could not adequately serve both Indian and anglo communities, particularly in a desert region of scarce rainfall and virulent heat. Competition for the Gila's flow quickly developed and favored the American settlements, as they were established upstream from the Indian lands. These American settlers appropriated an ever increasing amount of the river's water through the homesteading of public lands. This activity impinged upon Indian water use and resulted in persistent shortages for the tribal groups through the turn of the century.

The Indian Service struggled unsuccessfully to restore the tribes' water supply for sixty years. Throughout this period, local communities and the service realized that the river's available water could not sustain both social groups and that native communities were the ultimate victims. It was apparent that the only practical solution was additional development along the Gila River.

Coolidge Dam was finally authorized in the 1920's to remedy the Pima and Maricopa Indian communities' water needs and to resolve conflicts among users. The U.S. Indian Service constructed the dam between 1925 and 1928.

Cite this Record

Historic American Engineering Record: Coolidge Dam, Pinal County, Arizona. David M. Introcaso. 1986 ( tDAR id: 393145) ; doi:10.6067/XCV83F4QRP

Temporal Coverage

Calendar Date: 1928 to 1983 (operation of the San Carlos Irrigation Project)

Calendar Date: 1694 to 1924 (History of Pima Farming and Gila River water usage prior to Coolidge Dam construction)

Calendar Date: 1925 to 1928 (Coolidge Dam construction)

Spatial Coverage

min long: -110.537; min lat: 33.159 ; max long: -110.508; max lat: 33.188 ;

Record Identifiers

Historic American Engineering Record No.(s): AZ-7

NADB document id number(s): 2203101

NADB citation id number(s): 000000167205


Redaction Note: Sensitive information has been removed from the publicly accessible digital copy of this report. The following pages and/or plans have been redacted: Plans AZ-7-56 through AZ-7-111, Appendix III, Appendix IV, Appendix V, Appendix VI. Please contact the archaeologist at the USDI Bureau of Reclamation, Phoenix Area Office to obtain a complete digital copy of the report.

File Information

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