Columbia Basin Project

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The Columbia Basin Project is a water reclamation project located in east central Washington. The project covers affects about 671,000 acres. Original plans had the project taking over 70 years to complete. This report was developed in 1945, but the project stopped in 1985, far below its original expected completion. However, the project is still being considered if further needs arise.

The Columbia River generally sustains a heavy flow during the late spring and early summer. Flow generally peaks in mid-June. The project utilizes this heavy flow, which comes from the Rocky Mountains, western Montana, and northern Idaho, for irrigation, power generation, and reversible pump-generation. The project directly affects areas of Grant, Lincoln, Adams, Franklin, and Douglas counties.

The project is authorized and controlled by the Bureau of Reclamation as part of the Department of the Interior. The project was originally considered in 1902, but was determined at the time to be too difficult to complete. The project was then reconsidered in 1922 in a survey conducted by George Goethals. The first dam was built in 1941. Congress authorized the Columbia Basin Project Act in March of 1943. The project processes 2.3 to 2.7 million acre-feet of water annually, which can be used for generating electricity or irrigation. The Grand Coulee pumping station has a capacity of 314 megawatts, which is enough electricity to power about 188,000 Northwest homes.


The Grand Coulee component of the Columbia Basin Project includes the Grand Coulee Dam, Franklin D. Roosevelt Lake, The Grand Coulee

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Powerplant Complex, and the Grand Coulee Pump Generating Plant. The Bureau of Reclamation boasts that “The Grand Coulee Dam is one of the largest concrete structures ever built.” The water for the Grand Coulee Dam comes from the Franklin D. Roosevelt Lake. The original construction began in the 1930’s, but stopped during World War II and resumed after the war ended. Construction was completed in 1951. The annual volume inflow varies from 48.5 million acre-feet to 111.8 million acre-feet. The inflow from April to July accounts for nearly 70 percent of the average annual inflow. The total generating capacity of the Grand Coulee Pump-generating plant is 317,000 kilowatts.

====Banks Lake Banks Lake is an equalizing reservoir. It was built using two earth-filled dams at the north and south ends of the Grand Coulee.

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It is 27 miles long and has a storing capacity of 715,000 acre-feet. The Banks Lake feeds the Columbia River into the Main Canal. The south side of the canal was removed in order to expand the canal when six pump/generating units were added to the Grand Coulee Pump-generating plant. These changes increased the operating capacity to 26,000 cubic feet per second. Construction was completed in 1981.

====East High Canal and East Low Canal The East Low Canal was built for an initial capacity of 4,500 cubic feet per second. The canal begins at the bifurcation of the Main Canal. The Canal ends just east of the Scooteney Reservoir. Plans have been made to extend the canal to carry water to Connell, Mesa, and Eltopia, but the plans have been deferred.

The East High Canal is a proposed 88 mile long canal. It was designed to have an initial capacity of 7,500 cubic feet per second. The canal would serve lands east of the East Low Canal. In 1993 an Environmental Impact Statement was completed, but has yet to be filed. As of now, the Canal is still in deferred status.

Other components of the Columbia Basin Project include the Main Canal, the Pinto Dam, the West Canal, the O’Sullivan Dam, and the Potholes Canal.


The original plans of the Columbia Basin Project included a replacement of groundwater usage. However, plans to expand the project in the 1980’s were rejected on the basis of the environmental damage and the amount of funds required for the expansion of the project. Taxpayers currently support the Columbia Basin Project, which is the largest federally-run irrigation project. The monetary costs of the project for taxpayers is one of the largest of this kind in the country, which would only increase if the “second-phase” of the project were to be completed.

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The environmental impact of the project has also been called into question as a result of the talks of resuming construction continue. Columbia River salmon are one of many species that were listed as endangered in the 1990’s that are also threatened by the construction plans of the Columbia Basin Project. The salmon population is declining as a result of “low river flows and reservoir slackwater,” according to the Columbia Institute for Water Policy. The proposed expansion would draw even more water from the Columbia River, which would further endanger the survival of these species, including the salmon. The city of Odessa claims to be reaping none of the benefits assured by the Columbia Basin Project unless the construction is continued. However, only about half of the Odessa subarea would have been affected by the original plans.



Construction of the Columbia Basin Project allowed the irrigation of 671,000 acres of land which has led to the favorable growth of grain, alfalfa hay, ensilage crops, dry beans, fruit, sugar beets, potatoes, sweet corn, and seed and other specialty crops. In addition, the irrigation has assisted with the dairy farming and beef production in the area.

====Power The average annual net generation of the Grand Coulee Powerplant has been about 21.2 billion kilowatt hours. The power supplied by

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this plant supports a large portion of the power needs of the Pacific Northwest. The revenue from the plant is required by law to repay the power investment and to repay the irrigation investment of the Columbia Basin Project.

====Flood Control Franklin D. Roosevelt Lake is maintained to keep sufficient space to control the Columbia River at The Dalles in efforts to prevent flooding. The river is kept at no more than 450,000 cubic feet per second. The U.S. Army Corp of Engineers predict and control the amount of runoff and the amount of storage capacity needed. According to the Bureau of Reclamation, “The Grand Coulee Reservoir has 5,232,000 acre feet of capacity assigned to flood control. The Grand Coulee Project has provided an accumulated $173,976,000 in flood control benefits from 1950 to 1998.”


Hudson, John C. (2002). Across This Land: A Regional Geography of the United States and Canada. Baltimore: The Johns Hopkins University Press.

Bureau of Reclamation

Columbia Institute for Water Policy

Grand Coulee Dam

Columbia Basin Project

Bureau of Land Management: Columbia River Basin

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