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Canyon Ferry Unit
Photo of Canyon Ferry Dam, Montana
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Pick Sloan Missouri Basin Program
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Canyon Ferry Unit History (59 KB) (pdf)
General Description| Plan| Development| Benefits
General Description

The Canyon Ferry Unit of the Pick-Sloan Missouri Basin Program is a multiple-purpose project which makes an important contribution to the power supply, flood control, and irrigation in the upper Missouri Basin. Storage in Canyon Ferry Reservoir makes possible the irrigation of new land and supplemental irrigation of inadequately irrigated land in the upper Missouri area. Principal structures are Canyon Ferry Dam and Powerplant, about 17 miles northeast of Helena, Montana.

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Located 50 miles downstream from where the Gallatin, Madison, and Jefferson Rivers join to form the Missouri River, Canyon Ferry Dam intercepts the runoff from about 15,904 square miles, and stores the unused floodwater and unappropriated water in a 1,992,997 acre-foot reservoir. The reservoir permits upstream irrigation development by reregulating residual flows of the river for downstream powerplants.

In addition to providing power for irrigation pumping, Canyon Ferry Powerplant provides low-cost energy for use by farm, residential, and commercial consumers.

Facility Descriptions
Canyon Ferry Dam and Powerplant

Canyon Ferry Dam and Powerplant are on the Missouri River about 1.5 miles downstream from the original Montana Power Company`s Canyon Ferry Dam and 6,700-kilowatt powerplant in the backwater of Hauser Lake. The dam is a concrete gravity structure about 1,000 feet in length along the crest with a structural height of 225 feet. It contains 414,400 cubic yards of concrete.

The spillway is an overflow section in the central portion of the dam controlled by four radial gates. The spillway capacity is 150,000 cubic feet per second. The total reservoir capacity is 1,992,997 acre-feet at an elevation of 3800.0 ft. Four river outlets have a maximum discharge capacity of 9,400 cubic feet per second. One 13-foot-diameter pumping intake pipe is embedded in the concrete of the dam near the left abutment for the Helena Valley Pumping Plant. Three 13.5-foot-diameter penstock pipes for the power generating units are embedded in the dam near the right abutment.

The powerplant is on the right downstream toe of the dam adjacent to the spillway apron. It is of reinforced concrete construction and houses three 16,667-kilowatt vertical-shaft generators driven by 23,500-horsepower turbines.

Operating Agencies

Canyon Ferry Dam is operated by the Bureau of Reclamation. The Canyon Ferry Unit was transferred to operation and maintenance January 1, 1955.

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In 1846, the American Fur Trading Company established a post at Fort Benton which for many years was a major center of the area. The discovery of lode and placer gold at Bannock in 1862, and a year later at Virginia Gulch, brought a influx of prospectors and miners. Further discoveries of gold as well as rich deposits of silver and lead followed, and mining and smelting became an important industry.

Following the high silver production period, 1863-1893, a different type of settler moved into the area, and dryland farming and ranching operations began. The earliest agricultural enterprises were largely gardening and minor dairying around military forts and stage posts. Later, beef herds were driven into the area and stockmen began establishing headquarters along the stream valleys and in the foothills.


The first extensive survey of irrigation possibilities, both upstream and downstream from Canyon Ferry, was conducted in 1941 under terms of a three-party agreement between the Montana Water Board, Montana Power Co., and the Bureau of Reclamation. The results of the survey led to development of the water resources of the area.


The Canyon Ferry Unit was authorized by the Flood Control Act of December 22, 1944, Public Law 534, which approved the general comprehensive plan set forth in Senate Document 191, as revised and coordinated by Senate Document 247, 78th Congress, nd session.


Construction of Canyon Ferry Dam began May 24, 1949, and was completed June 23, 1954. The first power unit began operating December 18, 1953, followed by the other two in March 1954.

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Canyon Ferry Dam and Lake provide storage for irrigation development in the upper Missouri River Basin. The economic development of the areas benefited accrues to other units of the project. 


Canyon Ferry Reservoir is located in Montana about 50 miles downstream from where the Gallatin, Madison, and Jefferson Rivers join to form the Missouri River. This lake offers excellent fishing opportunity for rainbow trout, perch, ling, and walleye. Concrete boat ramps, campgrounds, day-use areas, shelters, swimming, and three marinas are available for recreational use. The Bureau of Land Management operates a visitor center at the lake.

Canyon Ferry Reservoir is one of the best in the country for viewing large concentrations of bald eagles. A wildlife management area at the end of the reservoir is managed by the Montana Department of Fish, Wildlife and Parks and is home to a colony of terns and pelicans. Barrow's Goldeneyes winter along the Missouri River. The upland areas around the reservoir provide habitat for Chestnut collared Longspurs and Longbilled Curlews, as well as hundreds of Pronghorn antelope.

For more specific information on the dam, visit Canyon Ferry Dam.

For information on recreation at Canyon Ferry Lake, visit Canyon Ferry Lake at Recreation.gov

Hydroelectric Power

Electric energy produced at the 50,000-kilowatt Canyon Ferry Powerplant is marketed by the Missouri River Basin Transmission Division Canyon Ferry Powerplant.

Flood Control

Canyon Ferry Reservoir has an exclusive flood control capacity of 101,089 acre-feet and a joint use capacity of 794,289 acre-feet for a total flood control capacity of 895,378 acre-feet and, as of 1998, has prevented $126.00 million in flood damages since 1973.

Conservation and Wildlife Enhancement

Since initial filling of Canyon Ferry Lake in 1955, wind blown, fine-grained material from exposed flats at the upper end of the lake have been a major contributor to air pollution in the area near the lake. The flats were exposed when the lake was drawn down to provide storage space for spring inflows or when water levels were low because of low precipitation and runoff. These conditions caused a deterioration of the living environment for farmers and stockmen in the general area and especially for the town of Townsend. These conditions also have an adverse effect on forage crops and livestock.

In June 1968, the Governor of Montana suggested that the best long-range solution would be attained through a cooperative program between the Bureau of Reclamation and the Montana Fish and Game Department. A dike system at the upper end of the lake that would include waterfowl development features had been planned by the Fish and Game Department, but was beyond the financial capabilities of that agency. Therefore, Federal assistance was requested. Construction began in 1972 and was essentially completed in 1978.

The waterfowl facilities provide habitat for nesting and breeding, supplemental resting and feeding sites for migratory birds, and public hunting and observation of waterfowl and upland game birds.

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Last updated: May 11, 2011