Bill Zawiski is Ohio’s water quality man and he knows the most efficient way to clean the infamously dirty Cuyahoga River that flows through Cleveland and other Ohio cities. It’s not a new regulation or cutting-edge infrastructure. The answer: tearing down old infrastructure — specifically, dams.

“If you are looking at the most economical way to gain watershed restoration, dam removal on its own jumps ahead of many things on the list,” says Zawiski, water quality supervisor with the Ohio Environmental Protection Agency.

Zawiski explains the science simply. Dams prevent waterways from cleaning themselves. When they are removed, the natural filtering process can work its magic.

“When the dams are removed, you are allowing that river to be free flowing, removing the chemicals the dam retains, and letting the river function in a natural way,” he says.

For about five years now, the Ohio EPA official has been working with local, state and federal agencies to move forward with an ambitious plan to tear down a 55-foot dam known locally as the Gorge Dam and clean up polluted sediment festering in its wake. The stately concrete waterfall was built in the early 1900s as a place to generate electricity, a purpose it ceased to serve in 1991 when nearby industry stopped relying on it for power. Aside from serving as a landmark in Gorge Metro Park, about 4 miles outside Akron, the dam serves no practical function. This is true of many of the 2 million to 2.5 million U.S. dams the EPA estimates are out there. However, they can impair water quality. Buried in the lake behind Gorge Dam are 832,000 cubic yards of sediment laced with arsenic, mercury and other harmful hydrocarbons that will have to be removed and then buried in a landfill.

John Waldman is a professor of biology at Queens College in New York. In 2015, he wrote an influential paper arguing that “no other action can bring ecological integrity back to rivers as effectively as dam removals.”

The paper got attention because it reinforced an idea gaining credence in many parts of the United States, particularly in urban regions where clean water and public waterfronts are both in short supply.

Since 1912, about 1,300 dams have been removed in the U.S. But in the last 10 years, the pace of de-damming has sped up considerably with nearly half of the removals happening since 2006.

“We have entered into a new era of dam removal because a broad array of people — ranchers, Native Americans, irrigators, businesses and communities — are realizing opening up and restoring rivers is an effective way to save taxpayer money, revitalize communities and help the environment,” says Michael Scott, acting environment program director at the Hewlett Foundation. To mark its 50th anniversary last year, the foundation is awarding $50 million in grants to fund community efforts to remove obsolete dams and restore rivers on the West Coast.

But $50 million is a drop in the rushing water where dam removals are concerned. Especially at a time like now, when federal support for the EPA and its environmental cleanup projects are being threatened. President Donald Trump has floated cutting the agency’s annual budget by nearly a third, to $5.7 billion. Though Trump’s proposal is just a starting point for budget negotiations with Congress and it’s possible that some EPA programs will be spared, there is no doubt that dam removal projects could be imperiled.

The Gorge Power Station, sometime before 1945 (Credit: Cuyahoga Falls Historical Society)

For Gorge Dam alone, the cost of removal and cleaning up left-behind sediment is estimated to be $70 million. The Ohio EPA is banking on the federal government to help cover some of that; the federal government is now working with the state agency on a preliminary design that will cost $1.4 million, $750,000 of which is coming from the state. A spokeswoman for the Ohio EPA says there is “no commitment” as of now for further assistance from Washington, but Cuyahoga Falls Mayor Don Walters has said that plans are in the works to lobby congressional and state representatives to sign letters of support for the project.

“A lot of these dams are unsafe and don’t serve any purpose anymore,” says Martin Doyle, director of the water policy program at Duke University’s Nicholas School of the Environment. “They represent making electricity and grinding grains and floating logs in a different era. There is certainly not many reasons to keep these dams, given that removing them lets the river oxygenate and clean itself up. But the big question is that even though there are not strong reasons to keep these dams, does that equate to spending tons of money to remove them in cities across the country?”

It’s a question that is being asked by local governments and the people they serve in dozens of communities, from Cleveland to Milwaukee to Colchester, Connecticut, and Washington State.

The American Society of Civil Engineers classifies almost a fifth of U.S. urban dams — 14,000 of 84,000 — as “high-hazard,” meaning there will be loss of life and significant economic loss downstream if they fail. The Association of State Dam Safety Officials estimates it would cost $21 billion to fix these dangerous, aging dams. Meanwhile, the U.S. Army Corps of Engineers projects that it would take $2 billion just to fix 20 of its most decrepit dams falling apart. Some of these aging dams are hydroelectric energy generators, some have flood control aspects to them, and some merely send water flowing into recreational lakes.