List of dams and reservoirs in Washington facts for kids
Dams are like giant walls built across rivers. They hold back water to create large lakes called reservoirs. These dams and reservoirs are super important for many reasons, like making electricity, providing water for farms and cities, and controlling floods. This article lists some of the main dams and the lakes they create in Washington state.
Washington state has a lot of dams – over 1,200! As of 2020, King County had the most, with 125 dams.
The largest dam in Washington is the Grand Coulee Dam on the Columbia River. It's the biggest in terms of how much space it takes up, how much water its lake can hold, and how much electricity it makes. The tallest dam is Mossyrock Dam on the Cowlitz River, standing 606 feet (185 meters) tall. The longest dam is O'Sullivan Dam on Crab Creek, stretching 19,000 feet (5,800 meters).
Important Dams in Washington
| Key | ||||
|---|---|---|---|---|
 This dam is on the border with Oregon. |
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| Dam Name | County | River | Reservoir (Lake) | Type | Power Made (MW) |
Height | Water Held | Year Built | Owner | Main Reason | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| feet | meters | acre.ft | dam3 | |||||||||
| Alder Dam | Pierce/ Thurston |
Nisqually River | Alder Lake | Arch | 50.0 | 330 | 100 | 241,950 | 298,440 | 1945 | Tacoma Power | Hydroelectric |
| Bonneville Dam† | Skamania | Columbia River | Lake Bonneville | Gravity | 1,242.0 | 197 | 60 | 537,000 | 662,000 | 1937 | U.S. Army Corps of Engineers | Hydroelectric, Navigation |
| Boundary Dam | Pend Oreille | Pend Oreille River | Boundary Lake | Arch-gravity | 1,070.0 | 340 | 100 | 95,000 | 117,000 | 1967 | Seattle City Light | Hydroelectric |
| Box Canyon Dam | Pend Oreille | Pend Oreille River | Box Canyon Reservoir | Gravity | 90.0 | 62 | 19 | 60,000 | 74,000 | 1956 | Pend Oreille Public Utility District | Hydroelectric |
| Chief Joseph Dam | Douglas/ Okanogan |
Columbia River | Rock Island Pool | Gravity | 2,620.0 | 135 | 41 | 516,000 | 636,000 | 1979 | U.S. Army Corps of Engineers | Hydroelectric |
| Cle Elum Dam | Kittitas | Cle Elum River | Cle Elum Lake | Earthfill | 165 | 50 | 436,900 | 538,900 | 1933 | U.S. Bureau of Reclamation | Irrigation | |
| Culmback Dam | Snohomish | Sultan River | Spada Lake | Rockfill | 112.0 | 262 | 80 | 165,774 | 204,479 | 1965 | City of Everett, Snohomish County PUD | Water supply |
| Cushman Dam No. 1 | Mason | North Fork Skokomish River | Lake Cushman | Arch | 43.2 | 235 | 72 | 453,400 | 559,300 | 1926 | Tacoma Power | Hydroelectric |
| Cushman Dam No. 2 | Mason | North Fork Skokomish River | Lake Kokanee | Arch | 81.0 | 175 | 53 | 8,000 | 9,900 | 1930 | Tacoma Power | Hydroelectric |
| Diablo Dam | Whatcom | Skagit River | Diablo Lake | Arch | 129.0 | 389 | 119 | 88,500 | 109,200 | 1930 | Seattle City Light | Hydroelectric |
| Dry Falls Dam | Grant | Grand Coulee | Banks Lake | Earthfill | 123 | 37 | 1,275,000 | 1,573,000 | 1949 | U.S. Bureau of Reclamation | Irrigation | |
| Gorge Dam | Whatcom | Skagit River | Gorge Lake | Gravity | 199.2 | 300 | 91 | 9,700 | 12,000 | 1961 | Seattle City Light | Hydroelectric |
| Grand Coulee Dam | Grant/ Okanogan |
Columbia River | Franklin Delano Roosevelt Lake | Gravity | 6,809.0 | 550 | 170 | 9,562,000 | 11,795,000 | 1942 | U.S. Bureau of Reclamation | Irrigation, Hydroelectric, Flood control |
| Hiram M. Chittenden Locks and Dam | King | Lake Washington Ship Canal | Lake Washington | Gravity | 0 | 26 | 7.9 | 458,000 | 565,000 | 1916 | U.S. Army Corps of Engineers | Navigation |
| Howard A. Hanson Dam | King | Green River | Howard A. Hanson Reservoir | Earthfill | 235 | 72 | 136,700 | 168,600 | 1961 | U.S. Army Corps of Engineers | Flood control, Water supply |
|
| John Day Dam† | Klickitat | Columbia River | Lake Umatilla | Gravity | 2,160.0 | 184 | 56 | 2,530,000 | 3,120,000 | 1971 | U.S. Army Corps of Engineers | Hydroelectric, Navigation |
| Ice Harbor Dam | Franklin/ Walla Walla |
Snake River | Lake Sacajawea | Gravity | 603.0 | 100 | 30 | 249,000 | 307,000 | 1962 | U.S. Army Corps of Engineers | Hydroelectric, Navigation |
| Kachess Dam | Kittitas | Kachess River | Kachess Lake | Earthfill | 112 | 34 | 239,000 | 295,000 | 1912 | U.S. Bureau of Reclamation | Irrigation | |
| Keechelus Dam | Kittitas | Yakima River | Keechelus Lake | Earthfill | 128 | 39 | 157,900 | 194,800 | 1917 | U.S. Bureau of Reclamation | Irrigation | |
| LaGrande Dam | Pierce/ Thurston |
Nisqually River | LaGrande Reservoir | Gravity | 65.0 | 192 | 59 | 2,700 | 3,300 | 1945 | Tacoma Power | Hydroelectric |
| Lake Tapps (Multiple dikes) | Pierce | Off-stream | Lake Tapps | Earthfill | 48,258 | 59,525 | 1911 | Cascade Water Alliance | Recreation, Water supply (proposed) |
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| Little Goose Dam | Columbia/ Whitman |
Snake River | Lake Bryan | Gravity | 810.0 | 96 | 29 | 516,300 | 636,800 | 1970 | U.S. Army Corps of Engineers | Hydroelectric, Navigation |
| Long Lake Dam | Lincoln/ Stevens |
Spokane River | Long Lake | Gravity | 71.0 | 213 | 65 | 105,000 | 130,000 | 1915 | Avista | Hydroelectric |
| Lower Baker Dam | Skagit | Baker River | Lake Shannon | Arch | 79.0 | 285 | 87 | 161,470 | 199,170 | 1925 | Puget Sound Energy | Hydroelectric |
| Lower Granite Dam | Garfield/ Whitman |
Snake River | Lower Granite Lake | Gravity | 810.0 | 100 | 30 | 440,200 | 543,000 | 1975 | U.S. Army Corps of Engineers | Hydroelectric, Navigation |
| Lower Monumental Dam | Franklin/ Walla Walla |
Snake River | Lake Herbert G. West | Gravity | 810.0 | 100 | 30 | 432,000 | 533,000 | 1969 | U.S. Army Corps of Engineers | Hydroelectric, Navigation |
| Masonry Dam | King | Cedar River | Chester Morse Lake/ Masonry Pool |
Arch-gravity | 30.0 | 215 | 66 | 93,900 | 115,800 | 1915 | Seattle Public Utilities | Water supply, Hydroelectric |
| Mayfield Dam | Lewis | Cowlitz River | Lake Mayfield | Arch-gravity | 162.0 | 250 | 76 | 133,764 | 164,995 | 1963 | Tacoma Power | Hydroelectric |
| McNary Dam† | Benton | Columbia River | Lake Wallula | Gravity | 986.0 | 183 | 56 | 1,350,000 | 1,670,000 | 1954 | U.S. Army Corps of Engineers | Hydroelectric, Navigation |
| Merwin Dam | Clark/ Cowlitz |
Lewis River | Lake Merwin | Arch-gravity | 136.0 | 313 | 95 | 422,000 | 521,000 | 1931 | PacifiCorp | Hydroelectric |
| Mossyrock Dam | Lewis | Cowlitz River | Riffe Lake | Arch | 300.0 | 606 | 185 | 1,685,000 | 2,078,000 | 1968 | Tacoma Power | Hydroelectric |
| Mud Mountain Dam | King | White River | Mud Mountain Lake | Earth/rockfill | 0 | 432 | 132 | 106,000 | 131,000 | 1948 | U.S. Army Corps of Engineers | Flood control |
| Pinto Dam | Grant | Off-stream | Billy Clapp Lake | Earthfill | 130 | 40 | 21,200 | 26,100 | 1948 | U.S. Bureau of Reclamation | Irrigation | |
| Priest Rapids Dam | Grant/ Yakima |
Columbia River | Priest Rapids Lake | Gravity/ Embankment |
955.6 | 178 | 54 | 237,100 | 292,500 | 1961 | Grant County Public Utility District | Hydroelectric |
| Rock Island Dam | Chelan/ Douglas |
Columbia River | Rock Island Pool | Gravity | 623.7 | 135 | 41 | 131,000 | 162,000 | 1933 | Chelan County Public Utility District | Hydroelectric |
| Rocky Reach Dam | Chelan/ Douglas |
Columbia River | Lake Entiat | Gravity | 1,299.6 | 130 | 40 | 382,000 | 471,000 | 1969 | Chelan County Public Utility District | Hydroelectric |
| Ross Dam | Whatcom | Skagit River | Ross Lake | Arch | 460.0 | 540 | 160 | 1,435,000 | 1,770,000 | 1949 | Seattle City Light | Hydroelectric |
| Skookumchuck Dam | Thurston | Skookumchuck River | Skookumchuck Reservoir | Earthfill | 1.0 | 190 | 58 | 34,800 | 42,900 | 1970 | TransAlta | Water supply |
| South Fork Tolt River Dam | King | South Fork Tolt River | South Fork Tolt Reservoir | Earthfill | 6.55 | 200 | 61 | 57,900 | 71,400 | 1964 | Seattle Public Utilities | Water supply |
| Swift Dam | Skamania | Lewis River | Swift Reservoir | Earthfill | 240.0 | 512 | 156 | 755,600 | 932,000 | 1958 | PacifiCorp | Hydroelectric |
| The Dalles Dam† | Klickitat | Columbia River | Lake Celilo | Gravity | 1,878.3 | 200 | 61 | 330,000 | 410,000 | 1957 | U.S. Army Corps of Engineers | Hydroelectric, navigation |
| Tieton Dam | Yakima | Tieton River | Rimrock Lake | Earthfill | 15.6 | 319 | 97 | 203,600 | 251,100 | 1925 | U.S. Bureau of Reclamation | Irrigation |
| Toutle River Sediment Retention Structure | Cowlitz | North Fork Toutle River | Earthfill | 0 | 184 | 56 | 160,000 | 200,000 | 1989 | U.S. Army Corps of Engineers | Sediment control | |
| Upper Baker Dam | Whatcom | Baker River | Baker Lake | Arch | 91.0 | 312 | 95 | 285,000 | 352,000 | 1959 | Puget Sound Energy | Hydroelectric |
| Wanapum Dam | Grant/ Kittitas |
Columbia River | Lake Wanapum | Gravity/ Embankment |
1,040.0 | 185 | 56 | 796,000 | 982,000 | 1963 | Grant County Public Utility District | Hydroelectric |
| Wells Dam | Chelan/ Douglas |
Columbia River | Lake Pateros | Gravity | 851.4 | 160 | 49 | 331,200 | 408,500 | 1967 | Douglas County Public Utility District | Hydroelectric |
| Wynoochee Dam | Grays Harbor | Wynoochee River | Wynoochee Lake | Gravity | 10.8 | 175 | 53 | 69,405 | 85,610 | 1972 | City of Aberdeen | Water supply |
| Yale Dam | Clark/ Cowlitz |
Lewis River | Yale Lake | Earthfill | 134.0 | 323 | 98 | 402,000 | 496,000 | 1953 | PacifiCorp | Hydroelectric |
Dams That Are No Longer There
Some dams have been removed over time. Here are a few examples:
- Condit Dam, on the White Salmon River in Klickitat County
- Elwha Dam and Glines Canyon Dam, on the Elwha River in Clallam County
More to Explore
- List of dams in the Columbia River watershed
- List of hydroelectric power stations in Washington
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List of dams and reservoirs in Washington Facts for Kids. Kiddle Encyclopedia.