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Parker-Davis Project History (102 KB) (pdf)
General Description| Plan| Development| Benefits


General Description

In 1954, the Parker Dam Power Project and the Davis Dam Project were consolidated to form the Parker-Davis Project. The major works include Davis (originally named 'Bullshead') Dam and Powerplant, Parker Dam and Powerplant, a high-voltage transmission system, and substations which sectionalize the long transmission lines. The original capacity of the Davis Powerplant was 225,000 kilowatts. Between 1973 and 1976, the generator stator windings were replaced, increasing the capacity of the powerplant to 240,000 kilowatts. The rated capacity of the Parker plant is 120,000 kilowatts. The transmission system currently includes more than 1,500 miles of high-voltage transmission lines and 32 substations. Parker Dam and Davis Dam are located on the Colorado River, 155 miles and 67 miles, respectively, downstream of Hoover Dam.

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Lake Havasu, formed by Parker Dam, provides a forebay and desilting basin from which The Metropolitan Water District of Southern California pumps water into its Colorado River Aqueduct. Parker Dam Powerplant was added to provide low-cost electrical energy to Arizona and southern California. Lake Havasu also serves as the forebay from which Colorado River water is pumped into central and southern Arizona via the Central Arizona Project. Davis Dam provides re-regulation of the Colorado River below Hoover Dam and facilitates water delivery to Mexico, as required by a 1944 Treaty. Davis Dam also generates power, contributes to flood control on the river, facilitates delivery of irrigation and municipal water supplies, and provides outdoor recreation opportunities and fish and wildlife habitat.

Facility Descriptions

Parker Dam spanning the Colorado River between California and Arizona near Parker, Arizona, is a concrete arch structure commonly called the 'deepest dam in the world.' Seventy-three percent of the dam's structural height of 320 feet is below the original riverbed; only about 85 feet of the dam's strucural height is visible (its superstructure rises another 62 feet above the roadway across the top of the dam). Parker Dam has a volume of 380,000 cubic yards of concrete. At its crest, the dam is 856 feet long. Water control is provided by five 50-foot-square gates.

Lake Havasu backs up behind the dam for 45 miles and covers more than 20,400 acres (32 square miles). The reservoir's total capacity is 646,200 acre-feet. The Metropolitan Water District`s W. P. Whitsett Intake Pumping Plant for the Colorado River Aqueduct is located on the shore of Lake Havasu about two miles upstream from the dam. The aqueduct begins at the intake pumping plant and extends 242 miles to its terminus at Lake Mathews near Riverside, California. About half of the power generated at Parker Dam is reserved by Metropolitan to pump Colorado River water along the Colorado River Aqueduct. The remaining power is marketed to users in California, Nevada and Arizona by the Western Area Power Administration. By contract, the use of active storage in Lake Havasu to generate power is limited to the elevation between 440 to 450 feet.

The Parker Powerplant includes a penstock gate structure, four penstock tunnels, and a powerplant building housing four hydroelectric generating units. Each of the four penstocks conveying river water from the forebay at the left end of the dam to the turbines is 22 feet in diameter and has a water capacity of 5,575 cubic feet per second. The plant's nameplate capacity is 120 megawatts.

Davis Dam spans the Colorado River between Arizona and Nevada near Laughlin, Nev. and Bullhead City, Ariz. The Mexican Treaty of 1944 required that the United States construct Davis Dam for regulation of water to be delivered to Mexico. The reservoir formed by the dam, Lake Mohave, is used for that purpose through integrated operations of Hoover and Davis Powerplants.

Davis Dam, rising 200 feet above the lowest point of the foundation and about 140 feet above the level of the river, is a zoned earthfill structure with concrete spillway, intake structure, and powerplant. It has a crest length of 1,600 feet, and a top width of 50 feet. Its reservoir, Lake Mohave, has a total storage capacity of 1,818,300 acre-feet, and at maximum capacity extends 67 miles upstream to the tailrace of the Hoover Powerplant.

Almost 5 million cubic yards of rock and earth were excavated to form the diversion and forebay channel and foundations for the dam, spillway and intake structures, and powerplant. More than 3,642,000 cubic yards of earth and rockfill were required to form the dam, and about 600,000 cubic yards of concrete and 23 million pounds of reinforcing steel were placed in the spillway, powerplant, and other structures.

The semi-outdoor type Davis Powerplant is on the Arizona side of the river immediately downstream from the dam embankment. Water is delivered from the forebay to the powerplant through five 22-foot-diameter penstocks. The plant's nameplate capacity is 240 megawatts.

Transmission System

The transmission system, operated by the Western Area Power Administration, includes 32 substations and transmission lines that have a total length exceeding 1,600 miles. The high-voltage switchyards near the Parker and Davis powerplants are the takeoff points for a system of transmission lines and substations that tie together the Davis, Hoover, and Parker Powerplants, and interconnect to load centers in central and southern Arizona, southern Nevada, and southern California.

Operating Agencies

The dams, hydroelectric powerplants, and attendant facilities are operated and maintained by the Bureau of Reclamation. The Parker Dam and Davis Dam Field Divisions of the Parker-Davis Project and the Boulder Canyon Project (Hoover Dam) were combined in a single operating unit administered by the Lower Colorado Dams Office located at Hoover Dam. The marketing functions, including the operation and maintenance of the transmission lines and attendant facilities of the Parker-Davis Project, are administered by the Western Area Power Administration.

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History and Investigations

Parker Dam. In the early 1900's, population growth of municipalities within California's greater Los Angeles area created a domestic water demand in excess of the supply from the local streams and the more remote Owens Valley source in northern California. After intensive investigations, it was determined that sufficient water could be obtained from the Colorado River. The construction of Hoover Dam, with its resulting river regulation and power generation, made it feasible to construct a dam on the Colorado River below the mouth of the Bill Williams River. Surveys initiated by the Bureau of Reclamation on June 25, 1934, established the best site for the location of Parker Dam.

Davis Dam. The Reclamation Service investigated a possible damsite at the lower end of Pyramid Canyon, 67 miles below Hoover Dam, as early as 1902-1903. Until Hoover Dam controlled the Colorado River, however, a dam at the Davis site was not practicable.

In 1930, the Bureau of Reclamation made further investigations and explorations of the site in Pyramid Canyon, which led to authorization of the Davis Dam Project.


The Parker-Davis Project was formed by the consolidation of the Parker Dam Power Project and the Davis Dam Project under the terms of the act of May 28, 1954 (68 Stat. 143). The Parker Dam Power Project was authorized by the Rivers and Harbors Act of August 30, 1935 (49 Stat. 1028). The Davis Dam Project was found feasible and authorized April 26, 1941, by the Secretary of the Interior under provisions of the Reclamation Project Act of 1939 (53 Stat. 1181).

On October 1, 1977, in conformance with Public Law 95-91, the Department of Energy Organization Act of August 4, 1977, the power marketing function of the Bureau of Reclamation, including operation and maintenance of transmission lines and attendant facilities, was transferred to the Department of Energy.


With funds advanced by the Metropolitan Water District of Southern California, contracts were awarded by the Bureau of Reclamation and excavation for Parker Dam and Powerplant began in October 1934. The dam was substantially completed in September 1938. Construction of the powerplant began in July 1939. Concurrently with construction of the powerplant, transmission lines and substations of the project were constructed and put into operation. Because of the onset of World War II, certain features were constructed with temporary materials or were omitted until proper materials could be made available and installed. Postwar work included replacement of temporary wood supporting structures with permanent steel structures in the substations.

A contract for the construction of Davis Dam and appurtenant works was awarded in June 1942. Work was halted after the War Production Board revoked priority ratings required to obtain the necessary materials for construction. Construction resumed in April 1946, and the project was completed in 1953.

Recent Developments

At Parker Dam, several hydropower units have been uprated with generator rewinds, turbine replacements, and the addition of solid-state excitation systems to improve their future performance. The five spillway regulating gates and hoists were also rehabilitated as of September 2002.

At Davis Dam, four of the five generators have been rewound and uprated to 51,750 kW.  One unit will not be rewound as it is still in good condition.

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Municipal and Industrial Water Supply
The Metropolitan Water District of Southern California, the nation's largest provider of treated drinking water, diverts water from Lake Havasu behind Parker Dam into the Colorado River Aqueduct for use in the southern California metropolitan area.  During a normal year, Metropolitan moves more than 1.5 billion gallons of water through its distribution daily, delivering supplies to 19 million Southern Californian homes and businesses in a 5,200-square-mile service area.  

The Central Arizona Water Conservation District also draws an average of 1.5 million acre-feet of Colorado River water annually from Lake Havasu for the Central Arizona Project (CAP) for use in central and southeastern Arizona. The CAP is a 336-mile long system of aqueducts, tunnels, pumping plants and pipelines and is the largest single resource of renewable water supplies in the state of Arizona.


Lake Havasu and the Parker Strip has become a major recreation area for boaters and fishermen, attracting thousands of people annually. In addition, a portion of the north end of Lake Havasu and most of the large marsh area extending 10 miles above the reservoir are included in the Havasu National Wildlife Refuge; the Bill Williams River National Wildlife Refuge connects with the reservoir near Parker Dam. Principal recreation activities at the reservoir are camping, picnicking, swimming, boating, and year-round fishing--primarily for striped and large-mouth bass, blue gills, and crappie. Migratory waterfowl hunting is permitted in season. Lake Havasu also is the site of the largest and most comprehensive warmwater fisheries project ever undertaken in the United States. A multi-agency effort, the program's goals are to increase sport fishing opportunities in Lake Havasu, improve access and facilities for shoreline anglers, and augment the dwindling populations of razorback sucker and bonytail chub, two endangered species of native Colorado River fish.

Lake Mohave is administered by the National Park Service as part of the Lake Mead National Recreation Area. Several National Park Service concessionaires operate in the area, providing numerous services, including lodging, boat rentals, trailer spaces, houseboat rentals and other modern amenities. Camping, picnicking, swimming, and boating are the major recreational attractions, and along with excellent year-round fishing in the reservoir. Lake Mohave also is home to the world's largest remaining population of the razorback sucker, a native Colorado River fish that is now endangered. Reclamation led the formation of a multi-agency Native Fish Work Group in an effort to maintain and restore this endangered fish

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

Bill Williams National Wildlife Refuge
Davis Dam
Davis Dam Camp
Havasu National Wildlife Refuge
Lake Mead National Recreation Area
Parker Strip Recreation Area

Hydroelectric Power

Davis, Hoover, and Parker Powerplants are interconnected through transmission systems owned and operated by the Western Area Power Administration. The Parker-Davis Project provides firm electric service to 26 municipalities, cooperatives, federal and state agencies and irrigation districts in Nevada, Arizona and California. The electrical integration of and interconnection of these Bureau of Reclamation powerplants provides maximum generation of power with efficient use of water resources. The highly developed agricultural base and complex industrialization of the Southwest benefit greatly from Colorado River hydroelectric energy.

Flood Control

To control flash floods on the Bill Williams River, the Corps of Engineers closed the gates at Alamo Dam on March 28, 1969. Since then, Parker Dam and Lake Havasu have been used for flood control regulation when the Corps is releasing large quantities of water to vacate the flood control pool behind Alamo Dam. Lake Havasu has a contractual operating range between 440 and 450 feet above mean sea level, but is generally operated between elevation 445 and 450 to support recreational use of the reservoir.

Both Parker and Davis Dams reregulate water releases from Lake Mead through the Hoover Dam powerplant for use downstream.

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Last updated: May 11, 2011