Historic American Engineering Record: South Canal, South of the Salt River, Mesa Vicinity, Maricopa County, Arizona

Historic American Engineering Record (HAER) No. AZ-52 presents a written historical summary and relevant historical documentation about the construction and use of the South Canal, which delivers water to Mesa, Tempe, Chandler and other parts of the Salt River Valley south of the Salt River for agricultural, industrial, and municipal uses. The report contains a narrative description, photographs, drawings, and maps.

The South Canal is the single, principal irrigation feature that delivers surface water from the Salt River at Granite Reef Dam to the farmers and residents on the south side of the Salt River. It encompasses portions of the Eastern Canal and the Consolidated Canal, and carries water to the Tempe Canal and to the Western Canal. The South Canal improved water distribution to the southside canals and provided water for a series of hydropower plants that supplied electricity to the Salt River Project and to south valley cities.

Built between 1907 and 1909, the original canal carried diverted water from the then newly-erected Granite Reef Dam (see HAER No. AZ-51 at https://core.tdar.org/document/393534) into a waterway that stretched only two miles southeast of the Salt River. When the Salt River Project (SRP) first opened in the early 1900's, many farmers, who held early water rights, did not recognize the advantages to joining the project and the Salt River Valley Water User's Association (the Association), because the canals that supplied water to them had their own headings and diversion points along the Salt River. In the 1910's, local farmers built new ditches and laterals to join the Association. In the 1920's, the majority of unsigned lands within the exterior of the Salt River Reservoir District became members of the project. The original South Side Canal was enlarged and expanded to accommodate all users on the south side of the Salt River; it grew to encompass parts of the Eastern and Consolidated canals.

Because the early founders of the Salt River Project saw the potential of hydropower, the Association contracted with the federal government in 1910 to build three power plants on the Salt River Project canals. Three hydropower plants were built along the South Canal. These plants provided needed power to an expanding Salt River Valley for commercial and domestic use.