Dams of the Columbia River Basin. Click to view higher resolution and read legend.Hydroelectric generators in the basin sized by capacity. 17 dams on the British Columbia side of Canada-US border not shown.
There are more than 60 dams in the Columbia River watershed in the United States and Canada. Tributaries of the Columbia River and their dammed tributaries, as well as the main stem itself, each have their own list below. The dams are listed in the order as they are found from source to terminus. Many of the dams in the Columbia River watershed were not created for the specific purposes of water storage or flood protection. Instead, the primary purpose of many of these dams is to produce hydroelectricity. As can be seen in the lists, these dams provide many tens of gigawatts of power.
Major dam construction began in the early 20thcentury and picked up the pace after the Columbia River Treaty in the 1960s, by the mid 1980s all the big dams were finished. Including just the dams listed below, there are 169 dams in the watershed, with 14 on the Columbia, 20 on the Snake, seven on the Kootenay, seven on the Pend Oreille / Clark, two on the Flathead, eight on the Yakima, and two on the Owyhee. Averaging a major dam every 72 miles (116km), the rivers in the Columbia watershed combine to generate over 36,000 megawatts of power, with the majority coming on the main stem. Grand Coulee Dam is the largest producer of hydroelectric power in the United States,[1] generating 6,809 megawatts, over one-sixth of all power in the basin.
In addition to providing ample power for the people of the Pacific Northwest, the reservoirs created by the dams have created numerous recreational opportunities, including fishing, boating, and windsurfing. Furthermore, by creating a constant flow and consistent depth along the river channel, the series of locks and dams have allowed for Lewiston, Idaho, to become the furthest inland seaport on the west coast of the United States.[2] Despite the numerous benefits to humans that the dams have provided, a number of environmental consequences have manifested as a result of the dams, including a negative impact on salmonid populations of the basin.[3]
The organization of the following lists begins with the Columbia River dams and is followed by dams on its tributaries (in order of length) and their respective watersheds. Additionally, the table of contents below is indented to indicate tributary status of each river.
Dams are listed in order from headwaters of each fork (North Santiam and South Santiam rivers) to their mouth at the confluence. There are no dams between the confluence and the mouth of the Santiam (Willamette River, OR).
Dams are listed in order from headwater (confluence of the Ohanapecosh River and the Clear Fork of the Cowlitz River, WA) to mouth (Columbia River, WA)
↑ Dam was initially completed in 1941; third power plant was begun in 1967 and completed in 1974.[9]
↑ Dam was initially completed in 1937; second powerhouse was completed in 1981
↑ The original dam was completed in 1911. In 1917, the dam was raised 17.5 feet (5.3m) to increase storage. Later, safety concerns were addressed and the new, modified dam was completed in 1989.[28]
↑ Original dam was completed in 1927. Due to deterioration, a replacement dam was commissioned and completed in 1978.[31]
1 2 3 4 5 Information received in email exchange with representative from Idaho Power.
↑ Initially completed in 1935, updated in 1995 with diversion structure and two powerhouses[35]
↑ Constructed with two power plants - A & B. Upper Salmon A was completed in 1937, Upper Salmon B, located a mile upriver from A, was completed in 1947.[35]
↑ Initially constructed by Greater Shoshone and Twin Falls Water Power Company in 1910, bought by Idaho Power in 1916 and updated in 1949.[35]
↑ A new power plant was built in the 1990s; this one was decommissioned and turned into a historical display[41][42]
↑ Dam and units one to four completed in 1959, unit five completed in 1980.[44]
↑ Dam and first three powerhouses were completed in 1975. Three further powerhouses, as well as modifications to Lewiston's water intake, were completed in 1987.[51]
↑ Dam was initially completed in 1961 with three generators online. Powerhouse units four through six were later added and online in 1976.[56]
↑ The first Wild Horse Dam was constructed in 1937. After the aggregate was found to be of poor quality, a new concrete, thin arch dam was completed in 1969, doubling the size of the reservoir.[62]
↑ Power plant located along the Owyhee Tunnel No. 1.[65]
↑ Power plant located along the Mitchell Butte Lateral.[65]
↑ Kootenay Canal Generating Station is located at the end of a canal created by the Corra Linn Dam.
1 2 Original dam constructed in 1944 created 140 MW; expansion completed in 2007 added 120 MW.[8]
↑ Although these rivers are not one, for the simplification of this list they will be listed together, as they are only separated by Lake Pend Oreille.
↑ This dam is made up of four sections with the highest being 110ft (34m) and the other three lower sections being 53ft (16m),[151]38ft (12m),[152] and 54ft (16m).[153]
↑ All forks of Flathead River are treated as being on main stem, as there is only one dam on any of the forks.
↑ Originally constructed in 1894, upgraded to concrete structure in 1933, with significant upgrades in the 1980s.[207]
↑ Beginning in 1892, dams were constructed at the mouth of Lake Chelan. After two failures, a more robust dam was constructed in 1903, providing electricity to Chelan. The current dam was completed in 1927.[227]
↑ Touchstone Nelson: Museum of Art and History (2007). "Upper Bonnington Dam". Archived from the original on September 26, 2018. Retrieved January 6, 2015.
↑ Touchstone Nelson: Museum of Art and History (2007). "Lower Bonnington Dam". Archived from the original on September 26, 2018. Retrieved January 6, 2015.
↑ Touchstones Nelson:Museum of Art and History (2007). "South Slocan Dam". Retrieved January 7, 2015.
↑ United States Bureau of Reclamation (October 13, 2013). "Hungry Horse Dam". Retrieved January 9, 2015.
↑ United States Bureau of Reclamation (October 21, 2013). "Hungry Horse Powerplant". Archived from the original on November 29, 2014. Retrieved January 9, 2015.
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