A History of the Salt River Project

SRP historical timeline


The Hohokam, a Pima word that means "those who have vanished," were peaceful farmers who inhabited the Salt River . They built 500 miles of irrigation ditches with stone and wooden tools. The Hohokam canal system served as many as 50,000 people. After living in the Valley for hundreds of years, the Hohokam inexplicably vacated the area, but they left a complex framework of irrigation engineering that began anew centuries later.

1860s - 1880s:

Beginning in the mid-1860s, mining and agricultural development in Arizona increased with the influx of settlers who desired to live in the Southwest. One of the Salt River Valley's first settlers was John W. "Jack" Swilling, who observed the Hohokam's ancient, but neglected canals. Swilling was intrigued with re-constructing these canals. His enthusiasm attracted business partners, and the Swilling Irrigating Canal Company dug the Salt River Valley Canal in 1867. These developments enticed more people to settle in the area and reap the benefits of a revitalized irrigation system.


By the 1890s, the Valley enjoyed an advanced irrigation system, but still suffered from droughts. The Tonto Basin dam site in a narrow canyon 80 miles northeast of Phoenix was identified as an ideal location to store the winter snow and rain runoff from the mountains above the Salt River and provide a reliable supply of water for delivery through the canals. For more than a decade, private companies and local communities tried unsuccessfully to finance a dam at the Tonto site. Meanwhile, a national movement was growing for federal financing of water reclamation projects.


Visionary president Theodore Roosevelt, who knew that the future of the United States lay beyond the Mississippi River, signed into law the National Reclamation Act. The Act allowed money from the sale of public lands in the West to be made available for water reclamation projects to enhance the growth and settlement of the western U.S. territories and states. The establishment of the National Reclamation Act came at a time when the Salt River Valley was in the grip of a terrible drought. Among the ranchers and farmers already settled in the area, the drought confirmed the need for a water storage system to assure a water supply during dry years.


In order to obtain money through the National Reclamation Act, ranchers and farmers in the Salt River Valley banded together to form the Salt River Valley Water Users' Association. They pledged their own land as collateral to repay federal loans to build a dam at the Tonto site. Prior to his tenure as governor, Joseph H. Kibbey wrote the Association's articles of incorporation.


On September 20, 1906, the U.S. Reclamation Service laid the six-ton cornerstone of Theodore Roosevelt Dam at the Tonto dam site. Stones for the dam were cut out of the canyon walls and set in cement manufactured at the site. Work went on around the clock, but was interrupted by several powerful floods. In order to meet the challenges of the remote location, a hydroelectric generator was built at the site to facilitate construction of the dam.


Excess power from Theodore Roosevelt Dam was delivered to irrigation pumps and other customers in the Salt River Valley, thus establishing hydropower as a "paying partner" for the water reclamation project.


More than 4,500 landowners were made party to the lawsuit Hurley vs. Abbot in order to settle water rights in the Valley. Edward H. Kent, the presiding judge, made his decision in 1910. The Kent Decree established what land would receive how much water from the Salt and Verde rivers.


Former President Theodore Roosevelt arrived in Arizona to dedicate Theodore Roosevelt Dam on March 18, 1911. In his speech, Roosevelt named the National Reclamation Act and the Panama Canal as two of the greatest accomplishments of his administration. At the time of the dedication, Roosevelt Lake was less than half full, but it contained more than 500,000 acre-feet of water and reaches 160 feet up the dam. It was enough water to sustain the Salt River Valley with two full years of irrigation, even if there were no further inflow.

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The Salt River Project (SRP) became important to the mining industry in Arizona through supplying hydroelectric power to the Inspiration Consolidated Copper Company of Miami. This power contract and other contracts helped assure the viability of SRP's electric system.


The Salt River Valley Water Users' Association (Association), which acted as a liaison to the U.S. Reclamation Service, received operational control of SRP's water and power facilities. In the Association's contract with the federal government, the United States retained title to the dams, canals and hydropower plants, and SRP remained a federal reclamation project and was able to use power revenues to reinvest into the project. SRP's headquarters were located at Van Buren Street and 2nd Avenue in Phoenix.


An earlier study showed the water table in the Salt River Valley was rising at a rate of 1.5 feet per year. The soil was waterlogged and the subsequent salt deposits rendered the land useless. In 1920, SRP shareholders assessed themselves to construct drains and install pumps to remove the rising groundwater.


Further advancing the "paying partnership" of power and water, SRP's General Superintendant C.C. Cragin designed a plan to finance and build three additional dams along the Salt River to include more hydroelectric generating capabilities. The dams included Mormon Flat Dam in 1925, Horse Mesa Dam in 1927 (pictured), and Stewart Mountain Dam in 1930.

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By the late 1920s, approximately 1,000 shareholders requested electric farm service so SRP embarked on an effort to extend electricity service to a growing residential and rural customer base. SRP's effort preceded the New Deal rural electrification project by 10 years.


In an effort to supplement its workforce during the Depression, SRP contracted with the Civilian Conservation Corps (CCC) to conduct maintenance and construction work on the canal system. The CCC crews typically completed projects including: building fences, creating trails for trucks, constructing levees or dykes, clearing laterals, lining and piping waterways, or upgrading water control structures with stone masonry or rubble lining. In less than three years, men from the CCC worked with SRP and for the Valley community completing over 700 separate jobs.


Maricopa County authorized the formation of the second part of SRP, the Salt River Project Agricultural Improvement and Power District. The District was formed as a political subdivision of the state of Arizona. The District was able to issue municipal bonds and proceeds from these bonds were used to redeem outstanding higher-interest bonds, thus assuring the financial health of SRP during the Depression and into the future.

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In the mid-1930s SRP received approval to dam the Verde River through the construction of Bartlett Dam. The dam was erected in 1,000 days and completed in 1939, which resulted in improved water supplies, while simultaneously providing much needed labor opportunities for unemployed Arizonans. Bartlett Dam was the first multiple-arch dam the Bureau of Reclamation constructed in the nation.


Due to many men serving in the military during WWII, SRP received help from the local prisoner of war camps in the Salt River Valley. German and Italian POWs worked on SRP's water transmission and distribution system.


SRP and Phelps Dodge negotiated the building of Horseshoe Dam, the second dam on the Verde River and the sixth storage dam in the water transmission and distribution system. The Phelps Dodge Corporation paid for the dam with financing from the federal Defense Plant Corporation in order to supply enough water to Phelps Dodge copper mines to meet production needs during WWII.


The District, which was established in 1937, becomes the entity responsible for the operation and maintenance of the power system. The Association continued to operate and maintain the water transmission and distribution system.


After WWII, SRP entered into contracts with the cities to deliver water to the rapidly urbanizing Salt River Valley. SRP entered into the first domestic water agreement with the City of Phoenix in 1952. Under these contracts, the cities were able to divert water from SRP canals at selected sites in order to deliver domestic water to SRP lands within their municipal boundaries. These contracts provided a stable water supply to the cities as SRP's service territory transitioned fro predominately agricultural to urban users.

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During the post-WWII era, SRP built three steam-generating stations in the Phoenix metropolitan area to keep pace with growth. The first facility was the Kyrene Generating Station built between 1952 and 1954 (pictured). The other generating stations included Agua Fria (1957-1961) and Santan (1972-1975).


The original $10.3 million debt on Theodore Roosevelt Dam and associated works was repaid to the federal government.


SRP partnered with other utility companies in the coordinated development of a regional power system that included power plants and many miles of long-distance transmission lines.


President Lyndon B. Johnson signed the 1968 Colorado River Basin Project Act, which authorized the construction of the Central Arizona Project (CAP). CAP is another major water construction and management project in Arizona and SRP lobbied heavily for its passage.


The first of three Navajo Generating Station (NGS) units was completed followed by the second and third units in 1975 and 1976. NGS in Page, Arizona was the biggest construction project SRP has ever attempted for a consortium of owners. Built on land within the Navajo Indian Reservation, the project launched a long, favorable and educational relationship between SRP and the Navajo Nation.

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The Reclamation Safety of Dams Act was passed authorizing work at 17 Western reclamation dams to bring them up to state-of-the-art safety standards. This Act and a reauthorization in 1984 eventually led to funding of more than $400 million in improvements at Stewart Mountain (pictured) and Theodore Roosevelt dams on the Salt River, and Bartlett and Horseshoe dams on the Verde River.


The Coronado Generating Station Unit One is completed near St. Johns, Arizona.


For the first time in its history, SRP's urban water use surpasses agricultural use, with 55 percent of its water deliveries going to urban areas and 45 percent of deliveries going to agricultural customers.

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The challenge of controlling aquatic weed growth in the canal has existed within SRP's system since its inception. The introduction of fish that eat canal vegetation is one of the methods that was devised to alleviate the problem. The white amur is a fish that eats more than its weight in water vegetation every day. In 1989, as part of a pilot program for weed control, over 1,700 white amur were introduced into portions of the Tempe and Crosscut canals. The white amur proved to be an effective form of weed control that minimized the use of chemical treatment in the canals.

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SRP began banking water at the Granite Reef Underground Storage Project to help ensure a reliable and adequate supply of water for the growing Phoenix metropolitan area. GRUSP was designed to enable the state of Arizona to maximize use of its Colorado River entitlement and help the state reach its "safe yield" goal. Safe yield is the equilibrium between the amount of groundwater pumped from an aquifer and the amount recharged into it.


In 1996 a modification project was completed that raised the height of Theodore Roosevelt Dam and expanded the lake's storage capacity. This increase offered Valley cities more water and, for the first time, provided SRP with substantial amounts of flood control and Safety of Dams storage space.


SRP was named a recipient of one of the world's highest and most distinguished awards for community and volunteer service. SRP received the coveted Award for Excellence in Workplace Volunteer Programs for 2000 from the Points of Light Foundation based in Washington, D.C.


SRP acquired C.C. Cragin (formerly Blue Ridge) reservoir from Phelps Dodge Corporation in 2005 as part of the Gila River Indian Water Rights Settlement approved by the Arizona Water Settlement Act. The agreement settled water rights issues and allowed for the transfer of C.C. Cragin reservoir from Phelps Dodge to SRP. The water stored behind the dam will be used for the benefit of SRP and its shareholders. This water supply will be used to meet domestic and municipal water demands in northern Gila County.


In 2006, SRP's Board of Directors approved a management proposal that directs SRP's future use of renewable energy resources and energy conservation measures. Among them are a diversified resource mix of wind, geothermal, large hydro (added in 2007) and low-impact hydro, landfill gas and solar (pictured at Agua Fria Generating Station). The approved portfolio sets a target of 15 % of SRP retail sales to be met through sustainable resources by fiscal year 2025.

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