The Salt River Project is Now Listed on the National Register of Historic Places

Written by: Emily Quinn

Historic photo of Bartlett Dam, part of the Salt River ProjectImagine the bustling metropolis of Phoenix, Arizona, without a reliable water supply and electricity. Before the construction of the Salt River Project, this image was reality. On August 7, 2017, the historical Salt River Project facilities were listed on the National Register of Historic Places in recognition of the fundamental role the Project played in the development of the Salt River Valley and of central Arizona, and also for its place in the Bureau of Reclamation’s own history. Soon after the end of the Civil War, American and Mexican settlers began to establish the towns and build the irrigation canals that are the foundation of today’s “Valley of the Sun.” They were successful; by 1910, 15,288 people lived in the towns and 92,000 acres were being farmed.

However, private resources could not fund the construction of a storage reservoir to hold water to irrigate through the summer, nor were the private entities able to engineer diversion structures able to withstand spring floods on the Salt River. These limitations made farming risky, and held back potential growth. Representatives traveled to Washington, D.C., and joined the ranks of other Westerners to ask the federal government to fund and construct irrigation works in the arid West.

For settlers in the Salt River Valley who persevered, their efforts paid off. In 1902, President Theodore Roosevelt signed the Reclamation Act, and soon after, Secretary of the Interior Ethan Allen Hitchcock established the U.S. Reclamation Service to design and build irrigation water storage and delivery systems. The irrigation representatives from the Salt River Valley played such a significant role in gaining support for the irrigation bill that Secretary Hitchcock named the Salt River Project as one of the first five projects that would be authorized under the Reclamation Act. Before the Salt River Project could be authorized under the Reclamation Act, Secretary Hitchcock asked valley irrigators to come together in order to resolve any outstanding disputes. He then tasked irrigators with creating a water users’ association, which sparked the formation of the Salt River Valley Water Users’ Association.

On March 14, 1903, Secretary Hitchcock authorized the construction of the Salt River Project and directed the USRS, eventually known as the Bureau of Reclamation, to construct a storage dam and a diversion dam on the Salt River. That single diversion dam, Granite Reef Diversion Dam, would serve the entire Project’s system of canals. The USRS began the work to construct a storage dam, Roosevelt Dam, in 1903 (completed in 1911) and started work on the Granite Reef Diversion Dam in 1906 (completed in 1908).

Since the Salt River Valley Water Users’ Association had already constructed irrigation canals, the USRS purchased those canals (and the water rights) from the private companies and converted them for Project use. To serve lands on the north side of the Salt River, between 1907 and 1912, the USRS purchased and enlarged the Arizona and Grand canals, and in 1913 completed construction of the new Crosscut Canal and the Crosscut Hydro Plant. To serve the south-side lands, in 1908 the USRS purchased the Consolidated Canal, including the associated Chandler hydro plant, and constructed the South Canal, and in 1911-1912 they constructed a portion of the Western Canal.

When the USRS lacked sufficient funds to finish the Western Canal, the Water Users’ Association completed that canal, as well as the Eastern Canal and the Highline laterals themselves, working under USRS engineers’ oversight. They received credits on their project assessments to compensate them for the cost of their construction efforts.

In the 1920s, the USRS purchased the Tempe Canal system, and the Consolidated Canal was extended toward Chandler to serve new lands. When drainage issues arose, Reclamation and the Water Users’ Association cooperated to design and construct a drainage system to prevent waterlogging, and to recycle drain water for irrigation use. The end product was an interconnected system of 1,300 miles of canals, laterals, ditches and drains that supply water to farms and communities within an approximately 375 square-mile water service area.

The USRS was authorized to build a storage dam and irrigation system, and limited hydropower developments to support construction work, to operate irrigation facilities and to replace electricity lost when the USRS shut down private plants on the Arizona Canal. The USRS, at that time, had no authority to build power plants to generate revenue.

However, the Water Users’ Association had no such legal limitation. The Association saw an opportunity to develop hydropower facilities using Project water and to apply the revenue toward repayment and maintenance. Between 1924 and 1930, the Association constructed three dams with power plants on the Salt River below Roosevelt Dam. Reclamation could release irrigation water from Roosevelt Lake, which would run through the Water Users’ power plants at Horse Mesa and then Mormon Flat dams.

Outside of irrigation season, that water would be stored behind Stewart Mountain Dam, and would eventually be released through that power plant during irrigation season. After Bartlett and Horseshoe dams were built on the Verde River to supplement the irrigation water supply, the Association could maximize power generation year-round. In the 1940s, the Association transferred ownership of their dams to Reclamation. The Salt River Project has played an integral role in developing the Salt River Valley into the industrious region as it is known today, by providing water and hydroelectric power to a once water-limited, desert area. The water and power attracted industry to the valley, and during World War II, supported a large military plant. These industries stayed after the war.

Post war, with the development of air conditioning systems, the valley boomed as people moved to the area to enjoy the hot, sunny climate. Project water and electricity were essential for this continued growth in population.

Growth was so great, the agricultural lands were eventually developed to build homes and infrastructure necessary to support these non-agricultural residents. By the early 1980s, when Phoenix became one of the 10 largest cities in the nation, the agricultural lands served by Project water dropped to less acreage than had been served in 1910, before the first Project irrigation water was delivered to Valley farms.

Ultimately, the Salt River Project changed with the times, extending its economic benefit beyond agriculture. It has enabled the valley to support new, expanding industries that now play important roles in the State’s financial prosperity, including the growth of the tech industry, tourism, recreation and the development of retirement communities. Between the project’s ability to support early 20th century agriculture in an arid state, and its current ability to support residents, businesses and entire industries with far-reaching water and hydroelectric power resources, there is no questioning why these historically significant project dams, power plants, and canals warranted listing on the National Register of Historic Places.

Visit Reclamation's SRP Flickr Album to see additional photos of the Salt River Project facilities listed on the National Register of Historic Places.

Published on October 26, 2017