General Description

The Salt River Project, located near Phoenix, Arizona, includes a service area of about 240,000 acres spanning portions of Maricopa, Gila and Pinal Counties in central Arizona. The land within the project is furnished a full irrigation water supply from the Salt and Verde Rivers and from 250 groundwater wells; about 26,500 acres are furnished supplemental irrigation water. The rivers are controlled by six storage dams, two of which were constructed by the Bureau of Reclamation. A diversion dam constructed by Reclamation serves 1,259 miles of canals, laterals, and ditches of which 842 miles are lined and piped.

The power system includes five hydroelectric plants; three steam plants, two with separate combustion-turbine installations; and a combined-cycle plant. In addition, the Salt River Project participates in four coal-fired generating stations and the Palo Verde Nuclear Generating Station, and built its own coal-fired station near St. Johns, Arizona. As of July 1983 (UPDATE????), the power system also included 1,533 circuit miles of transmission lines, 5,183 circuit miles of overhead distribution lines, and 11,146 cable miles of underground distribution lines.

Plan

Water is furnished by the Salt and Verde Rivers, which drain a watershed area of 13,000 square miles. The four storage reservoirs on the Salt River form a continuous chain of lakes almost 60 miles long. An important supplemental supply is obtained from well pumping units.

Irrigation flow is regulated by Bartlett Dam on the Verde River and Stewart Mountain Dam on the Salt River. Downstream of the confluence of the Verde and Salt Rivers, water is diverted to two main canals at the Granite Reef Diversion Dam. The Arizona Canal serves the north side of the project; the South Canal serves the south side. From the two main canals, water is diverted to secondary canals, then to laterals through which the water is delivered to farms and cities. Total storage capacity of Salt River reservoirs is more than 2.4 million acre-feet. The combined storage capacity of the two reservoirs on the Verde River is 317,715 acre-feet.

Total hydroelectric generating capacity is 232 megawatts, including power from the pumped storage units at Horse Mesa and Mormon Flat Dams. Turbine generating units at these two dams produce power during periods of peak demands. The turbines can be reversed to pump water during off peak periods from the lower reservoir back to the upper reservoir for repeated usage. As part of the same program, which began in 1969, existing units at the two dams were converted from 25 to 60 hertz, and one new 60-hertz unit replaced the former 25-hertz units at Theodore Roosevelt Dam. A hydroelectric unit located on the crosscut canal, which links the project's two major canals, provides additional hydroelectric capacity.

Unit descriptions and facilities

Theodore Roosevelt Dam and Reservoir

Theodore Roosevelt Dam, the first major structure constructed by the Bureau of Reclamation on the Salt River Project, is located about 76 miles northeast of Phoenix and 30 miles northwest of Globe, Arizona. The dam, completed in 1911, was subsequently modified between 1989 and 1996.  The original dam was a cyclopean, rubble-masonry, thick-arch structure that spanned the Salt River to form a reservoir of 1,381,580 acre-feet. It was 280 feet high, 723 feet long at the crest, and contained 355,800 cubic yards of masonry,

In 1936, the spillways were modified by lowering crests 6 feet to increase their capacities, and installing individual gate hoists, operating motors, and two 5-kilovolt-ampere gasoline-engine driven generators.

From 1989 to 1996, the dam was modified by the Bureau of Reclamation.  The modification raised the dam 77 feet in elevation, increasing its water conservation storage capacity by 20 percent, adding flood control space to the reservoir, and addressing concerns about its safety as well as the safety downstream dams.  In addition to raising the dam´s height, the modification included construction of two new spillways, installation of new outlet works, and powerplant modifications.  Also, existing recreation facilities at Roosevelt Lake were improved, and new recreational facilities were constructed.

Lake Roosevelt is 22.4 miles long, with 128 miles of shoreline and almost 21,500 surface acres. 

Horse Mesa Dam and Reservoir

Located on the Salt River 65 miles northeast of Phoenix, Horse Mesa Dam is a concrete thin-arch structure 305 feet high. Constructed by the Salt River Valley Water Users' Association during 1924-1927, the dam contains 162,000 cubic yards of concrete, and forms a 245,138 acre-foot reservoir.

The spillway, as modified in 1936 by the Bureau of Reclamation, included a 50,000 cubic foot per second, concrete-lined auxiliary tunnel, 30 feet in diameter and 400 feet long; a regulating gate, gatehouse, and operating mechanism for controlling the tunnel; and a concrete discharge apron below the existing spillway. The piers on the radial-gate spillways were thickened, individual motor-driven gate hoists were installed, and two 15-kilovolt-ampere gasoline-engine driven generators were installed for emergency operation of the hoist motors.

Mormon Flat Dam and Reservoir

Mormon Flat Dam, a 224-foot high concrete thin-arch structure, is on the Salt River 51 miles northeast of Phoenix. Constructed by the Salt River Valley Water Users' Association from 1923-1926, it creates a 57,852 acre-foot reservoir.

In 1938, Reclamation completed construction of a new gate structure and a concrete-lined spillway discharge channel, and installed two 50-foot-square stoney regulating gates, hoists, motors, two 25-kilovolt-ampere gasoline-engine driven generators, and a new road to the powerhouse.

Stewart Mountain Dam and Reservoir

On the Salt River 41 miles northeast of Phoenix, Stewart Mountain Dam created Saguaro Lake, a 69,765 acre-foot capacity reservoir. The dam is a concrete thin-arch structure, 207 feet high, with gravity abutments. When built by the Salt River Valley Water Users' Association from 1928-1930, the dam included an open, super-elevated channel spillway equipped with radial gates.

The spillway was modified by Reclamation in 1936. The work consisted of building a concrete-lined spillway discharge channel, 450 feet long by 265 feet wide, below the existing ogee spillway; reconditioning the hoisting equipment for the radial gates; and installing individual gate operating motors and two 10-kilovolt-ampere gasoline-engine driven generators.

From 1988 to 1992, the dam was again modified by Reclamation, to meet concerns about its stability in a probable maximum flood or maximum credible earthquake.  To address PMF concerns,  a new spillway was constructed on the dam's right abutment to increase its ability to safely release flood waters.  As part of earthquake protection measures, a new concrete overlay was placed over areas on the right and left abutments to improve the dam's stability. T he existing power penstock and river outlet works were also replaced, the road on the top of the dam was raised and widened, and the existing left spillway and spillway wall was modified. In addition, drainage holes were drilled at selected locations in the dam's foundation to help relieve hydraulic uplift pressures, and some areas of the foundation were grouted to help reduce seepage. Finally, 84 steel cables were installed through the dam and into its foundation to strengthen it.

Bartlett Dam and Reservoir

From 1936-1939, Bartlett Dam was constructed by Reclamation on the Verde River, 48 miles northeast of Phoenix. This multiple-arch dam is 287 feet high, contains 182,000 cubic yards of concrete, and creates a 178,490 acre-foot capacity reservoir.

Bartlett Dam was also recently modifyed by Reclamation to address safety concerns.  The modification, initiated in March 1994, included construction of a new, unlined auxiliary spillway about 1,500 feet south of the dam´s left abutment, along with a concrete control structure and three-segment fuseplug embankment along with training dikes. In addition, the dam was raised 21.5 feet to prevent overtopping, and the walls and bridge of the existing service spillway structure were modified.  Modifications were completed in  December 1996. 

Horseshoe Dam and Reservoir

Horseshoe Dam, on the Verde River 58 miles northeast of Phoenix, is an earthfill structure 194 feet high, with a reservoir capacity of 139,238 acre-feet.  Horseshoe Dam was built from 1944-1946 by the Phelps-Dodge Copper Products Corp. for the Salt River Valley Water Users' Association under a water exchange agreement.  Spillway gates were added to the dam in 1949 by the city of Phoenix to increase the domestic water supply.

Horseshoe Dam has also been modified by Reclamation to address concerns about its safety in the event of a Probable Maximum Flood or Maximum Credible Earthquake.  The modification began in May 1993, and was completed in _____________.  Modifications included construction of a fuse plug auxiliary spillway with an erodible embankment and a concrete foundation 2,000 feet west of the existing spillway.  In addition, a 148,000 cubic-yard stability berm was constructed at the downstream toe of the dam to help stabilize it in the event of an earthquake, and the dam was raised eight feet to enable the spillway to pass the Probable Maximum Flood. To prevent overtopping of the structure from wave action, an additional 4-foot parapet was built on the dam´s crest. Other work included relocation of the dam tender facilities, upgrading the road to the public boat ramp, and study and protection of archaeological artifacts during construction.

Granite Reef Diversion Dam

Granite Reef Diversion Dam is located about 4 miles downstream of the confluence of the Salt and Verde Rivers and about 22 miles east of Phoenix. The dam was constructed between 1906 and 1908 by Reclamation to divert water released from storage to project canals.

Well Pumping Units

Pumps are installed on 250 wells to supplement the surface water supply. The total pumping capacity of these wells is 738,595 acre-feet. Several booster pumps have been installed to lift water to canals and laterals through low lifts ranging from 3 to 40 feet.  (INFORMATION CURRENT?)

Distribution and Drainage System

A total of 131 miles of irrigation canals, 878 miles of laterals, and 250 miles of drain ditches make up the water distribution system.  (INFORMATION CURRENT?)

Operating agencies

The Salt River Valley Water Users' Association operated and maintained the irrigation and drainage system below Granite Reef Diversion Dam from November 1, 1917, to 1949, and the power features were operated by the Salt River Project Agricultural Improvement and Power District until 1937.  In 1937, the Association transferred all of its rights, title and interest in the Salt River Project to the District.  In 1949, the original agreement was amended so the District would assume construction, operation and maintenance responsibilities for both the electric and irrigation systems.  The District then delegated to the Association operation and maintenance of the irrigation and water supply system of the project.

Development

Irrigation of the Salt River Valley began about 1867. The riverflow was erratic, varying from a small stream to enormous floods. During years of drought, the supply of water at low river stages was inadequate for the land in cultivation. River flows in excess of immediate needs or canal capacities were lost, due to lack of storage facilities.

From 1867 to 1902, a number of diversion dams, canals, and laterals were constructed by private companies or through community effort. Difficulties caused by lack of water storage, inadequate diversion dams, and inequitable water distribution were so critical that many of the settlers left the valley. A committee was named to investigate the feasibility of a water storage system. A reservoir site located 80 miles from Phoenix, where Tonto Creek flowed into the Salt River, seemed the most practical.

Such a reservoir would cost from $2 to $5 million. As a territory of the United States, Arizona was prohibited from assuming such a large-scale debt; private investors could not be induced to take on the financial risk necessary to construct the dam.

The Salt River Valley Water Users' Association was incorporated on February 9, 1903, for the purpose of furnishing water, power, and drainage for the benefit of approximately 4,800 individual landowners.

Power Developments

When Phoenix and the surrounding communities began to grow, patterns of water distribution were affected. A great impact was also felt on electrical service provided by the Salt River Project.

In 1947, power sources included the hydroelectric facilities at the dams and on the Crosscut Canal and gas/oil-fired units at Crosscut. In 1952, the Kyrene Steam Plant, south of Tempe, was placed in operation and in 1971-1973, three combustion turbines were added, increasing the plant capacity from 104 to 250 MW.

In 1957, the Agua Fria Generating Station, located west of Glendale, was placed in operation. Since then, the station's capacity has been increased to 600 MW.

In 1969, the Salt River Project initiated its Hydroelectric Expansion and Frequency Unification (HEFU) program to increase hydroelectric generating capacity at facilities on the Salt River. This program included the installation of pumped storage units at Mormon Flat Dam in 1971 and at Horse Mesa Dam in 1972. The HEFU program also provided for converting the conventional hydroelectric generating facilities at the dams on the Salt River from the outmoded 25-hertz (Hz) to the modern frequency of 60 Hz and in 1973, a new 60-Hz, 36-MW generating unit was installed at Theodore Roosevelt Dam, which replaced the existing 25-Hz units.

In 1974-1975, the four-unit combined-cycle Santan Generating Station was built near Gilbert, Arizona. This station has an installed capacity of 300 MW.

In December 1979, the project completed Unit 1 at its coal-fired Coronado Generating Station near St. Johns, Arizona.  In October 1980, the plant´s second unit was completed, bringing it to its full 760 MW capacity.

Salt River Project Participation in Power Projects

The Salt River Project and five Southwestern utilities invested in the construction of two of the large coal-fired units at the Four Corners Generating Station near Farmington, New Mexico. The project has a 10-percent share of units 4 and 5 of the 2,040-MW capacity plant. First power was received in 1969 and the second unit went on line in 1970.

In 1974-1976, three coal-fired units came on line at Navajo Generating Station near Page, Arizona. The Salt River Project manages the station and receives 21.7-percent of its installed capacity, which is 2,250 MW.

In 1976, a second unit of the Hayden Generating Station at Hayden, Colorado, was completed. The Salt River Project receives 50 percent of the 262-MW coal-fired unit's capacity.

The 1,580-MW Mohave Generating Station near Laughlin, Nevada, was built by a regional group of utilities. The project has a 10 percent interest in this station. Power from the first unit was delivered in 1970 and the second unit became operational in 1971.

The Palo Verde Nuclear Generating Station was constructed 55 miles west of Phoenix, Arizona, from June 1976 to January 1988.  Salt River Project is one of the seven utilities that receives power from the 3,810 MW-capacity plant.  SRP´s share is 17.5 percent.

Investigations

The project was investigated and found feasible by the Director of the Reclamation Service on March 7, 1903.

Authorization

The project was authorized by the Secretary of the Interior on March 14, 1903, in accordance with the act of June 17, 1902 (32 Stat. 338). Rehabilitation and betterment of the project works was authorized by the act of October 7, 1949 (63 Stat. 724), as amended.

Construction

Construction was started on August 24, 1903, and the first water was delivered in 1907.

The original project system, composed of' Theodore Roosevelt Dam and Powerplant, Granite Reef Diversion Dam, and the improved main canals, was placed in service in 1909 and completed in 1911. The Salt River Valley Water User's Association built Horse Mesa, Stewart Mountain, and Mormon Flat Dams during 1923-1930. On November 26, 1935, the association entered into a contract with the Bureau of Reclamation for the construction of Bartlett Dam, reconstruction or repairs to the spillways at Horse Mesa, Mormon Flat, Stewart Mountain, and Theodore Roosevelt Dams, and other improvements. All the work was started in 1936 and completed by 1939. In 1946, the Phelps-Dodge Corporation completed Horseshoe Dam on the Verde River under a water exchange agreement. From 1989 to 1998 (???), Reclamation modifyed several of the dams on the Salt and Verde Rivers.

Benefits

Irrigation water from the project helped transform a part of the Arizona desert into fertile farmland that produces millions of dollars worth of crops annually. The project delivers more than a million acre-feet of irrigation water to municipal, agricultural and urban irrigators in a 240,000-acre service area each year.  Principal crops are wheat, grain sorghum, pasture, grain, alfalfa, barley, and citrus. (CROP DATA ACCURATE?)

Power

The Salt River Project, with an installed capacity of more than 5,000 MW, provides electric service to more than 700,000 residential, business and industrial customers in a 2,900-square-mile service area in parts of Maricopa, Gila, and Pinal Counties.

Flood Control

Capacity assigned to flood control is 556,000 acre-feet.  The Salt River Project has provided accumulated flood control benefits of $1,419,267,000 from 1950-1999.

Recreation and Fish and Wildlife

All reservoirs located on the Salt and Verde Rivers offer year-round boating and fishing for a variety of warmwater fish species. Waterfowl hunting is permitted in season. Theodore Roosevelt Lake contains a wildlife area and, as a wildlife refuge, is posted to permit hunting at certain times of the year. Theodore Roosevelt and Apache Lakes offer year-round motel rental facilities. Canyon, Saguaro, and Bartlett Lakes offer a variety of camping, picnicking, swimming, and other outdoor recreation opportunities. The Salt River below Stewart Mountain Dam offers outstanding trout fishing during certain times of the year. During 1993 the Salt River Project recorded 1,070,690 12-hour visitor days. (UPDATE??)

The first hard-surface bicycle path placed on Salt River Project right-of-way was completed in 1975. The 11.5-mile Papago Loop Bicycle Path was made possible through an agreement between the project and the cities of Phoenix, Tempe, and Scottsdale.

For specific information about any of these recreation sites, click on the name below.

Apache Lake
Bartlett Reservoir
Canyon Lake
Horseshoe Reservoir
Lake Pleasant
Saguaro Lake
Theodore Roosevelt Lake

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