Historic American Engineering Record: Mormon Flat Dam, Maricopa County, Arizona and Horse Mesa Dam, Maricopa County, Arizona

Together, Historic American Engineering Record (HAER) Numbers AZ-14 and AZ-15 describe the origins, development, and expansion of power generation and delivery facilities along the Salt River to service residents of the Salt River Valley. This report, HAER No. AZ-14, presents a full narrative history of the Reclamation Service's and the Salt River Valley Water User's Association's efforts to expand the Salt River Project's hydroelectric program. It details the construction and use of Mormon Flat Dam, which impounds water along the Salt River to form Canyon Lake, and the construction and use of Horse Mesa Dam, which impounds water along the river to form Apache Lake. It also includes photographs, drawings, and maps of Mormon Flat Dam. HAER No. AZ-15 (see https://core.tdar.org/document/393155) contains photographs, drawings, maps, and/or plans that detail the construction and use of Horse Mesa Dam.

Mormon Flat Dam was the first dam constructed under the Salt River Project's 1920's hydroelectric expansion program. Currently, the dam is operated by the Salt River Project for the purposes of generating hydroelectric power and for storing approximately 57,000 acre feet of water for agricultural and urban uses. Horse Mesa Dam was the second dam constructed under the Salt River Project's 1920's hydroelectric expansion program. Currently, this dam is operated by the Salt River Project for the purposes of generating hydroelectric power and for storing approximately 245,000 acre feet of water for agricultural and urban uses.