A guide to major hydropower dams of the Columbia River Basin

A map of Columbia and Snake River dams and fish protection facilities

Choose a dam or see all dams:

Hydroelectricity in the Columbia River Basin

Not long after Northwest pioneers established the first cities in the region, they began to capture the power of falling water to make electricity for their homes and industries.

They were the first to tap the great hydroelectric potential of the Columbia River Basin, a region that includes parts of Washington, Oregon, Idaho, Montana, Wyoming, Utah, Nevada, and British Columbia. It is an area considerably larger than the country of France.

Today, the Northwest relies on hydropower for about two-thirds of its electricity, and 40 percent of all U.S. hydropower comes from the Columbia system.

    photo: willamette falls power station
Willamette Falls Power Station, 1889
Oregon Historical Society photograph
(click to enlarge)

The T.W. Sullivan Dam at Willamette Falls in Oregon City was the first hydroelectric dam in the lower Columbia Basin. It was built in 1888, 37 years after the founding of Portland.

Washington Water Power Company built the Monroe Street Dam on the Spokane River in downtown Spokane in 1896, just 15 years after the city of Spokane Falls was platted and seven years after fire destroyed 32 blocks of the downtown business district. In Spokane, as elsewhere in the Northwest, hydroelectric power and progress were linked.

The city of Idaho Falls built the first hydroelectric dam on the Snake River in 1904. The nearby Minidoka Dam, a federal project, followed in 1906. Development of other dams in the Columbia and Snake basins proceeded at a rather slow pace during the early 1900s.

Hydroelectric development in the basin really began in earnest in the 1930s with the damming of the mainstem of the Columbia and Snake rivers. The first, in 1933, was Rock Island Dam near Wenatchee. Bonneville Dam followed in 1938. Construction of dams on the Columbia and Snake rivers continued into the 1970s, with most of the development occurring between 1950 and 1970.

Today there are 56 dams built exclusively for hydropower in the Columbia River Basin, and hydropower now supplies roughly 50 percent of the electricity used in the Northwest. 74 percent of the power generating capacity in the Columbia River basin is hydropower, 38,670 megawatts of the 52,357 megawatts total. The mainstem of the Snake River not only has more dams than any other tributary in the Columbia Basin, it has the largest dams of any tributary in the basin.

In addition to the 56 hydropower dams, there are 77 multiple purpose projects in the basin that include hydropower production. Other benefits provided by many of the dams include navigation for large barges; irrigation to farms in drier areas; launching areas for recreational activities; and flood control.

While the dams brought tremendous advantages, they also posed problems to the region. They are obvious physical barriers to the salmon and steelhead that hatch in the tributaries and migrate through the mainstem Snake and Columbia to the ocean as juveniles, and back home to spawn as adults.

In 1982, at the behest of Congress, the Northwest Power and Conservation Council adopted the Columbia River Basin Fish and Wildlife Program. It is designed to reverse some of the damage to fish and wildlife caused by hydropower and to increase protection in the future.

The Council’s program calls for permanent solutions to improve fish survival at dams, such as screens and bypass systems to channel juvenile fish migrating downstream away from the dams’ turbines, surface bypass systems, and spill for fish passage. 
Fish spill and/or bypass systems are in place at all dams downstream of Chief Joseph Dam on the Columbia and Hells Canyon Dam on the Snake. Those two dams do not have fish passage facilities.

The map identifies the United States dams along the mainstem of the Columbia and Snake rivers. In addition to historical information, the map describes the dams and the types of fish protection facilities, including those for downstream and upstream fish passage.