Canyon Ferry Dam is a concrete gravity dam in a narrow valley of the Missouri River, United States, where the

Big Belt Mountains The Big Belt Mountains are a section of the Rocky Mountains in the U.S. state of Montana. Situated mainly in the Helena National Forest, the mountains are used for logging and recreation for the surrounding residents. Nearby are the cities of Hel ...

and the Spokane Hills merge, approximately downstream from the confluence of the Gallatin, Madison, and Jefferson rivers, and about east of the city of Helena, Montana. The dam is for

flood control Flood control methods are used to reduce or prevent the detrimental effects of flood waters."Flood Control", MSN Encarta, 2008 (see below: Further reading). Flood relief methods are used to reduce the effects of flood waters or high water level ...

, irrigation, recreation and hydroelectric power. The building of the dam created a

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

known as Canyon Ferry Lake.

Background

In 1941, the first study for the dam was carried out by the

Bureau of Reclamation The Bureau of Reclamation, and formerly the United States Reclamation Service, is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and opera ...

, the Montana Water Board and Montana Power Company. The dam and power plant were part of the Pick-Sloan Plan and approved by the Flood Control Act of 1944 which was signed on December 22. Known as the Canyon Ferry Unit, construction began on May 24, 1949, and was completed on June 23, 1954. On December 18, 1953, the power plant's first generator became operational and the other two went online in 1954. The 1949 structure replaced the original Canyon Ferry Dam upstream. The original dam was constructed between 1896 and 1898 by the Helena Water and Electric Power Company. It was a timber crib dam with rock-fill and was high and long.

Design

The dam is a tall concrete gravity type and has a length of . The crest of the dam is while the base is . The dam structure compromises a total of of concrete. The dam's

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure th ...

is located on its central portion and is controlled by four radial gates. It has a maximum discharge of . Adjacent to the spillway is the dam's power plant which contains three 16.5 MW Francis turbine generators for an installed capacity of 50 MW. Each turbine is fed with water by a diameter

penstock A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and sewerage systems. The term is inherited from the earlier technology of mill ponds and watermills. H ...

. At a normal elevation of , the

contains of water.

References

External links

U.S. Reclamation website: Canyon Ferry Unit
{{Authority control Dams in Montana Buildings and structures in Lewis and Clark County, Montana Hydroelectric power plants in Montana Gravity dams United States Bureau of Reclamation dams Energy infrastructure completed in 1954 Dams completed in 1954 Dams on the Missouri River 1954 establishments in Montana