Why Pennsylvania Is Removing Its Dams—And How It’s Helping Fish, Rivers, and Communities
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Asia Tabb
Aired; July 7th, 2025.
Listen to the podcast to hear the full conversation.
With thousands of dams scattered across its waterways, Pennsylvania has a complicated relationship with its aquatic infrastructure. But a growing number of those dams—especially small, aging, and obsolete ones—are being taken down. And for good reason.
“A dam is any sort of manmade obstruction in a waterway that impounds water,” said David Dippold, Ph.D., Fish Passage Biologist with the Pennsylvania Fish and Boat Commission, in an interview with The Spark. “There are a whole bunch of them in Pennsylvania,” he explained, noting that many were built centuries ago to power mills, harvest ice, or create swimming areas.
Today, many of those purposes no longer exist. Instead, the dams sit unused, deteriorating, and in some cases, creating safety or environmental hazards. That’s why Pennsylvania has become a national leader in dam removals, with over 400 removed so far.
While the official count of dams in Pennsylvania hovers around 3,000, Dippold believes the real number could be twice that.
“Now we have formal processes for constructing and permitting these types of structures,” he said, “but that wasn’t always the case. So there are small dams in forests or agricultural settings that aren’t even on the official list.”
The Pennsylvania Fish and Boat Commission works with partners to remove dams that no longer serve a useful purpose.
“Like all infrastructure, there’s a lifespan to these things,” Dippold said. “Where they’re not serving a purpose, we’re interested in removing them.”
Pennsylvania removes an average of 15 to 25 dams per year, but the process is far from simple. According to Dippold, it’s “a two-to-three year process for two or three weeks worth of work.” That includes securing a willing landowner, finding grant funding, completing engineering designs, and receiving regulatory approval from the state Department of Environmental Protection.
For aquatic life, dam removal is like tearing down a brick wall in the middle of their home.
“Fish live in a linear network,” Dippold said. “When there’s a dam, it prevents access to habitats they need to live out different aspects of their life—feeding, reproducing, finding colder water.”
Dam removal restores the flow and health of rivers and streams. “It’s the movement of organisms, water, and material,” Dippold added. “All of those things are restored when you remove the structure and allow the river or stream to freely flow.”
