This is a list of dams in the United States that have been removed as physical impediments to free-flowing rivers or streams. Dams are not included if they have instead failed, or if they have been decommissioned but not yet removed. Dam removal takes many forms, and some removals may leave structures behind or alter the natural course of a river.
According to the non-profit advocacy organization American Rivers, 2,119 dams were removed in the United States between 1912 and 2023. The peak year was 2018, which saw 109 removals. Pennsylvania removed 390 dams in this period, more than any other state. Mississippi is the only state with no documented dam removals.[1]
The 46feet[2] Brown Bridge Dam, 56feet[3] Boardman Dam, and 34feet[4] Sabin Dam were removed from the Boardman River in Michigan as part of the Boardman River Dams Ecosystem Restoration Project after their hydropower was decommissioned in 2005.
The 100adj=onNaNadj=on privately owned Rindge Dam on Malibu Creek in the Santa Monica Mountains of California was built in 1924 and has been allowed to completely fill with sediment, making it functionally obsolete but still a potential hazard. Malibu Creek once supported the southernmost steelhead population in the world. But today, steelhead no longer occupy the creek.
The similar 1947 Matilija Dam near Ojai, California was built against the advice of the U.S. Army Corps of Engineers, among others, and also blocked steelhead trout spawning grounds. After being notched twice and largely silted up, 90% of its design capacity has been lost. As of 2013 stakeholders agree that the dam and its sediment be removed, but no funding source has been identified.[5]
Built in 1916, the 25feet[6] Fossil Creek Dam supported hydroelectric power production on Fossil Creek, a tributary of the Salt River via the Verde River. The dam was removed in 2008 to restore flow, travertine deposition, and native fish populations.[7]
The 710feet Glen Canyon Dam has been proposed for removal because of the negative effects it has on the water quality and riparian habitat of the Colorado River in Grand Canyon National Park. In addition, the reservoir impounded behind it, Lake Powell has filled all of the canyons for up to 160miles above the dam. This lake, while providing recreational opportunities, has eliminated more than 160miles of habitat for endangered Colorado River fish species.
The reservoir also loses more than 6 percent of the total annual flow of the Colorado River to evaporation and seepage.[8] Advocates of dam removal such as the Glen Canyon Institute also cite these losses of stored water as reason to decommission the dam. If it were to be removed, it would dwarf any completed dam removal project in history.
On the South Fork Clearwater River, the Grangeville Dam was a 56-tallNaN-tall, 440-longNaN-long arched concrete hydroelectric dam constructed by the Washington Water Power Company in 1911. A wooden fish ladder had been installed but it collapsed in 1949. The dam was removed in the interest of fish passage and since the hydropower facilities had become obsolete. The dam was destroyed by dynamite at 6:35 PM on August 19, 1963, following two prior detonations that day which had failed to collapse the structure.[9] At the time, the dam was the largest ever to be removed, a record which stood for decades.[10]
In 1971 the tall Lewiston Dam was removed from the main stem of the Clearwater River just above its confluence with the Snake River. Built in 1927 as a hydroelectric facility, the dam lacked fish ladders and was rendered obsolete by the downstream Lower Granite Dam.
On the White Salmon River, the Condit Dam blocked access for Pacific Salmon and steelhead runs on of river. PacifiCorp proposed to remove the dam, rather than paying for fish passage upgrades. Removal was proposed in 2006, but actions from Skamania and Klickitat counties held up the process. In fall 2008, salmon were trucked up above to dam to allow them to spawn higher up the river. In October 2011, PacifiCorp contractors used explosives to blow a 15feet hole in the dam to drain its reservoir and allow young salmon to enter the Columbia River and head to sea.
The 21feet Milltown Dam lay the junction of the Clark Fork River and Blackfoot River in Montana. The dam held very high levels of toxic sediments from 100 years of mining and logging. Its 2008 removal improved water quality, trout habitat, and the general ecological condition of the watershed.[11]
On the Sandy River in Oregon, the 50feet tall Marmot Dam was removed by Portland General Electric in 2007. Its removal has been extremely successful at improving access for Pacific Salmon and steelhead to the upper Sandy River watershed up into the Mount Hood Wilderness.
Four dams along the lower Snake River, built and still operated by the United States Army Corps of Engineers, serve as hydroelectric power sources as well as maintaining an inland port at Lewiston, Idaho for agricultural barge traffic. The four are candidates for removal because of millions of cubic yards accumulated behind the dams, which are raising water levels for riverside cities. They include: the 1975 100feet Lower Granite Dam, the 1970 98feet Little Goose Dam, the 1969 100feet Lower Monumental Dam, and the 1962 100feet Ice Harbor Dam.
Three million new cubic yards of sediment are deposited behind the lower four dams on the Snake River annually.[12] The city of Lewiston, Idaho and others along the Snake have built a system of levees maintained by the Army Corps of Engineers. The levees in Lewiston were designed to leave five feet between water levels and the top of the levees. As of 2011, two feet remained. As water levels continue to rise, either some of the dams must be removed or dredged, or the municipal levees will continue to be raised. The Corps admits that the amount of sediment in the riverbed is too great for dredging to be effective, and Lewiston community leaders are worried that higher levees will further cut the town off from its rivers.[13] The Corps began dredging behind Lower Granite Dam in 2015.[14]
The 6feet tall Cuddebackville Dam on the Neversink River was built in two portions dating from the 1820s (for water diversion into a canal) and 1915 (for hydroelectric power). The dam had been abandoned since 1945, and was removed in October 2004 by the U.S. Army Corps of Engineers in a novel partnership with the Nature Conservancy. The removal benefited aquatic life in the area, specifically the Dwarf Wedge Mussel and the American Shad.
The Elwha Ecosystem Restoration project on the Olympic Peninsula of Washington started in 2012, and finished in 2014, the 108feet Elwha Dam and the 210feet Glines Canyon Dam were removed to restore stocks of Pacific Salmon and trout species to the Elwha River watershed. The removal of these blockades allows migratory salmon to travel past the dam sites and upriver, an event that has not occurred since the dams' creation in 1913. After spawning there, the salmon die and their carcasses decompose, releasing marine nutrients laid down in their bodies as they fed in the open ocean. This reintroduction provides a valuable research opportunity for interested parties.[15] Since the dam removal, reservoir beds that looked like moonscapes have returned to vibrant rich habitat. Within a year of the Elwha Dam removal, an increase in salmon-derived nutrients was documented in the American dipper.[16]
Built in 1837, the 24feet tall Edwards Dam on the Kennebec River in Maine blocked passage to Atlantic Salmon and American Shad. Its 1999 removal was the result of a landmark case in which a U.S. federal agency, the Federal Energy Regulatory Commission, required the decommissioning and removal of a dam against the operator's wishes.
After more than 20 years of advocacy from the Un-Dam the Klamath movement, the largest dam removal in history started,[17] the first of four dams - the Copco Number 2 Dam - was removed in fall 2023,[18] and the removal project was completed in August 2024.[19]
Two dams have been removed as part of the Penobscot River Restoration Project: the Great Works Dam in 2012 and the Veazie Dam in 2013, each tall.[20]
In 2008, the 80feet tall Elk Creek Dam was removed from the Elk Creek tributary to the Rogue River.
O'Shaughnessy Dam in California was completed in 1923 and represented the first great environmental controversy in the US as it was constructed in a national park.[21] The debate over the dam and reservoir continues today. Preservationist groups such as the Sierra Club lobby for the restoration of the valley, while others argue that leaving the dam in place would be the better economic and environmental decision.[22]
The two remaining dams on the Kinnickinnic River in River Falls, Wisconsin are being considered for removal in order to completely restore the Kinnickinnic River to its natural state.[23] The Kinnickinnic River, called the Kinni for short, is a 22adj=midNaNadj=mid[24] river in northwestern Wisconsin in the United States. The Kinni is a cold water fishery supporting a population of native Brook Trout and naturally reproducing Brown Trout. The Kinnickinnic River is officially designated as a Class I trout stream by the WI DNR, indicating it is a "high quality" trout water that has sufficient natural reproduction to sustain populations of wild trout, at or near carrying capacity.[25] The Kinnickinnic is also designated as an Outstanding Resource Water (ORW) by the WI DNR both above State HWY 35, and below the Powell Falls Dam, however, the stretch of the Kinni through the City of River Falls is not included in this designation where the river is impounded into two reservoirs which do not support a fishery. This ORW designation indicates the Kinni provides outstanding recreational opportunities, supports valuable fisheries and wildlife habitat, has good water quality, and is not significantly impacted by human activities.[26] This designation indicates that the State of Wisconsin has determined the Kinnickinnic River warrants additional protection from the effects of pollution. These designations are intended to meet federal Clean Water Act obligations requiring Wisconsin to adopt an “antidegradation” policy that is designed to prevent any lowering of water quality – especially in those waters having significant ecological or cultural value.[26]
Local stakeholder organizations in the FERC relicensing process include the Friends of the Kinni, the Kiap-TU-Wish Chapter of Trout Unlimited, the Kinnickinnic River Land Trust, and the River Alliance of Wisconsin. Government agencies also serving as stakeholder organizations include the Wisconsin DNR, the US Fish and Wildlife Service, and the National Park Service.
This list includes all known removals of dams greater than or equal to in height.
| Matilija Dam | Ojai, CA | Matilija Creek | Ventura River | |||
| Rindge Dam | 2025–2035 | Malibu Creek State Park, CA | Malibu Creek | Santa Monica Bay |
| Glen Canyon Dam | Coconino County, AZ | Colorado River | Colorado River | |
| O'Shaughnessy Dam | Yosemite National Park, CA | Tuolumne River | San Joaquin River | |
| Ice Harbor Dam | Franklin County and Walla Walla County, WA | Snake River | Columbia River | |
| Lower Monumental Dam | Franklin County and Walla Walla County, WA | |||
| Little Goose Dam | Columbia County and Whitman County, WA | |||
| Lower Granite Dam | Garfield County and Whitman County, WA |
See main article: List of dam removals in Alabama.
See main article: List of dam removals in California.
See main article: List of dam removals in Connecticut.
See main article: List of dam removals in Delaware.
See main article: List of dam removals in Florida.
See main article: List of dam removals in Georgia (U.S. state).
See main article: List of dam removals in Idaho.
See main article: List of dam removals in Louisiana.
See main article: List of dam removals in Maine.
See main article: List of dam removals in Maryland.
See main article: List of dam removals in Massachusetts.
See main article: List of dam removals in New Hampshire.
See main article: List of dam removals in New Jersey.
See main article: List of dam removals in New York (state).
See main article: List of dam removals in North Carolina.
See main article: List of dam removals in North Dakota.
| Dam | Dam height | Watercourse | Removal completed | Notes |
|---|---|---|---|---|
| Pinery Feeder Dam | Cuyahoga River | 2020 | [27] | |
| Brecksville Dam |
See main article: List of dam removals in Rhode Island.
See main article: List of dam removals in South Carolina.
See main article: List of dam removals in Tennessee.
See main article: List of dam removals in Vermont.
See main article: List of dam removals in Virginia.
See main article: List of dam removals in West Virginia.
See main article: List of dam removals in Washington, D.C..
| Dam | Watercourse | Removal completed | Notes |
|---|---|---|---|
| Island Woolen Mill Dam | Baraboo River | 1972 | Opened of a Wisconsin River tributary to fish and wildlife.[28] |
| Reedsburg Woolen Mills Dam | 1973 | ||
| Wonewoc Dam | 1996 | ||
| Waterworks Dam | 1998 | ||
| Oak Street Dam | 2000 | ||
| LaValle Dam | 2001 | ||
| Linen Mill Dam | 2001 |
| Dam | River | Removal timeframe | Notes |
|---|---|---|---|
| Junction Falls Dam | Kinnickinnic River | 2023–2040 | In 2018, River Falls, Wisconsin, approved the removal of two little-used dams in the city. This would return the Kinnickinnic River to a free-flowing state and restore the city's namesake falls.[29] |
| Powell Dam | 2025–2040 |
See main article: List of dam removals in Wyoming.