By Anna Spitzer | US Environmental Policy Student

Dams in the United States are an increasingly aging infrastructure class and are omnipresent throughout the nation. There are almost 100,000 dams large enough to be included in the Army Corps’ National Inventory of Dams (NID), and the average age of these dams is 63 years old, and over 9,000 dams in the NID are over 90 years old.^[1] While dams can provide a multitude of services — hydropower, flood protection, water storage, recreation, irrigation, and river navigability improvements — there are environmental and safety trade offs to be considered as they age. In the American Society of Civil Engineers’ 2025 infrastructure report card, the American Society of Civil Engineers gave the United States’ dam infrastructure a grade of “D+”, finding that the number of high hazard potential dams (where either a breach or misoperation would lead to a probable loss of human life) is increasing, with over 2,300 deficient high hazard dams in the nation.^[2] The costs to repair dam infrastructure only continues to rise as their upgrades are delayed,^[3] and as dams age and climate change worsens, a new issue is arising — there is a higher risk of dam failure under climate change as the number of extreme weather and precipitation events increases.^[4]  US natural resource policy needs to adequately address this growing risk and provide funding for projects that would remove dams whose purpose is no longer effectively being served given the opportunity dam removal presents to both improve public safety and additionally improve environmental health.

Beyond hazard risk, dams have a multitude of environmental impacts on the streams and rivers that they hold back — from preventing fish migration, slowing rivers and increasing sedimentation, altering habitats, and degrading water quality. Large reservoirs increase greenhouse gas emissions from the decomposition of organic matter in stagnant waters. Under both climate change induced drought and higher temperatures, the amount of dissolved oxygen in reservoirs decreases, which causes anoxic conditions and furthers decomposition and greenhouse gas emissions.^[5] Dam removal, even of small dams, has been shown to improve fish passage, water quality, biodiversity outcomes, and restore habitat.^[6] In a case study of the Dead Lake Dam in Florida, observed fish species grew from 34 to 61 following its removal.^[7] Dams that endanger fish populations has been a long-contested issue by environmental and Native groups — especially regarding salmon migration and spawning patterns in the West. Famously, the discovery of the endangered Snail Darter fish in the Little Tennessee River led to the 1978 Supreme Court case Tennessee Valley Authority v. Hill, which ruled in favor of environmental groups aiming to protect the fish and stop the construction of the Tellico Dam under the Endangered Species Act (although the dam would later be exempted from this law and completed in 1980).

The Klamath dam removal project — the largest dam removal project in US history — is an example of successful large-scale dam removal managed by multiple regulatory agencies. The Klamath River’s water rights have been long contested by upstream farmers and downstream Native American groups. In 2010 (and amended in 2016), the Klamath Basin Restoration Agreement was signed by the states of California and Oregon, multiple counties, NGOs, irrigation districts, and farmers, which included provisions for the removal of four dams that separate the upper from the lower basin.^[8] The Federal Energy Regulatory Commission (which regulates and licenses hydroelectric projects), Bureau of Land Management, National Park Service, and US Forest Service collaborated to make sure that the dam removals met the standards of the Wild and Scenic River Act.^[9] The removal of the four dams was completed in October 2024, and cost $450 million USD that was funded through Pacificorp (the owner) and California state bonds — although this cost is far lower than it would have been to refurbish the dams, the most recent of which was built in 1964.^[10] Additionally, the Bipartisan Infrastructure Law has made available $162 million over the next five years towards restoration of the Klamath basin.^[11] Today, salmon can migrate to the upper Klamath River basin spawning grounds for the first time in over a century, and the river is recarving its original path — a huge ecological win.

Dam removal continues to grow as an option in the United States that policy changes need to continue to embrace, given the majority of dams in the United States no longer effectively serve their original purpose.^[12] American Rivers estimates that up to 85 percent of the nation’s dams are at best no longer useful, and at worst pose a public safety risk.^[13] The Klamath may be the largest of these projects to have taken place, but smaller removals are happening across the nation. There were 80 dams removed in the United States in 2023, and trends in dam removal are increasing year over year.^[14]  In spite of its benefits, dam removal is still greatly complicated by regulatory oversight at the state-level. 70% of the dams in the NID are state-regulated and over 50% are privately-owned.^[15] Federal requirements for dam removal can include FERC licensing (only if hydroelectric), Endangered Species Act consultation, NEPA review, and Rivers and Harbors Act permitting. Most states have a dam safety program responsible for dam oversight as well as their own environmental review systems in place. To accelerate dam removal at the state level, other states should follow the lead of North Carolina. In 2017, North Carolina passed SB 107: Streamline Dam Removal, a law that reviewed the permitting system in the state, created an explicit state review under the Clean Water Act, and made it easier for small and/or low hazard dams to be approved for removal.^[16]

At the federal level, the Bipartisan Infrastructure Law included $2.4 billion towards the removal or rehabilitation of dams and $4.5 billion for watershed restoration.^[17] Under the current administration, the dispersal of BIL funds for dam removal is unclear, although a court did recently order the Trump administration to end the freeze of already awarded IIJA and IRA funding.^[18] These infrastructure improvements should have bipartisan support — the funds would go towards improving public safety, water quality, and ecosystem health. In 2021, the 21st Century Dams Act, a bipartisan bill, was introduced but was never voted on by Congress. The act would have allotted almost $25 billion towards removal and rehabilitation projects.^[19] The 21st Century Dams Act would be a step in the right direction and should be reintroduced to Congress. Additionally, states need to organize to sue the federal government for frozen BIL funding — a step already being taken by Pennsylvania in regards to the IRA.^[20] Overall, the trend of dam removal increasing in the United States is a positive move in the right direction that needs to continue to be aided by policy improvements. Efforts must continue to be taken at the state level to streamline the permitting process for small dam removals, and at the federal level, there needs to be large scale investment in larger and extensive restoration projects given both the public safety and environmental health impac

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^[1]United States Army Corps of Engineers. (2024). National Inventory of Dams. https://nid.sec.usace.army.mil/#/

^[2] American Society of Civil Engineers. (2025). 2025 report card for America’s infrastructure. https://infrastructurereportcard.org/cat-item/dams-infrastructure/

^[3] Ibid.

^[4]Hwang, J., Lall, U. (2024). Increasing dam failure risk in the USA due to compound rainfall

clusters as climate changes. npj Nat. Hazards 1(27),  https://doi.org/10.1038/s44304-024-00027-6.

^[5] World Bank Group’s Water Global Practice. (2017). Greenhouse Gases from Reservoirs Caused by Biogeochemical Processes. World Bank. https://documents1.worldbank.org/curated/en/739881515751628436/pdf/Greenhouse-gases-from-reservoirs-caused-by-biogeochemical-processes.pdf

^[6] Nargi, L. (2025). How tearing down small dams is helping restore northeast rivers. Yale Environment 360. https://e360.yale.edu/features/northeast-dam-removals#:~:text=American%20Rivers%20estimates%20that%2085,38%20of%20them%20since%202018.

^[7] Hill, M., Long, E., & Hardin, S. (1994). Effects of dam removal on Dead Lake, Chipola River, Florida. Florida Game and Fresh Water Fish Commission. https://hdl.handle.net/20.500.14394/29043

^[8] Klamath Basin Settlement Agreements. (2025, April 22). https://www.congress.gov/crs-product/R42158

^[9] Rosebrough-Jones, S. (2023). The largest dam removal in the US gets approved on the Klamath. National Park Service. https://www.nps.gov/articles/000/klamath-dam-removal.htm

^[10] Profita, C. (2022). The world’s largest dam removal will touch many lives in the Klamath River Basin. OPB.org. https://www.opb.org/article/2022/11/18/klamath-river-dam-removal-southern-oregon-dams-northern-california-drought/

^[11] https://www.fws.gov/program/klamath-basin-project-awards

^[12] Ho, M., U. Lall, M. Allaire, N. Devineni, H. H. Kwon, I. Pal, D. Raff, and D. Wegner (2017), The future role of dams in the United States of America, Water Resour. Res., 53, 982–998, doi:10.1002/2016WR019905.

^[13] American Rivers (2023). Importance of dam removal factsheet. https://www.americanrivers.org/wp-content/uploads/2023/11/Fact-Sheet-The-Importance-of-Dam-Removal.pdf

^[14] American Rivers. (2023). Summary 2023 US dam removals. https://www.americanrivers.org/wp-content/uploads/2024/02/DamRemovalCompiledSummaries_2024.pdf

^[15] United States Army Corps of Engineers. (2024). National Inventory of Dams. https://nid.sec.usace.army.mil/#/

^[16] North Carolina General Assembly. (2017). SB 107. https://www.ncleg.net/Sessions/2017/Bills/Senate/HTML/S107v4.html

^[17] Kober, A. (2021). Infrastructure bill funds urgent clean water and river restoration needs. American Rivers. https://www.americanrivers.org/media-item/infrastructure-bill-funds-urgent-clean-water-and-river-restoration-needs/

^[18] Magill, K. (2025) Trump administration ordered to resume IIJA, IRA funding. Construction Dive. https://www.constructiondive.com/news/judge-orders-trump-reinstate-iija-ira-funding/745582/

^[19] National Hydropower Association. (2021). Kuster, Young, Feinstein Introduce Bipartisan Legsilation. https://www.hydro.org/news/kuster-young-feinstein-introduce-bipartisan-legislation-to-address-climate-change-restore-rivers-improve-public-safety-and-modernize-hydropower/

^[20] DiGangi, D. (2025). Pennsylvania Gov. Shapiro sues Trump admin over IRA funding freeze. ESG Dive. https://www.esgdive.com/news/shapiro-sues-trump-administration-frozen-funding-inflation-reduction/740240/