LULU GARCIA-NAVARRO, HOST:
Every year, dozens of aging dams are removed from U.S. rivers. That's something that can bring dramatic transformations downstream. Murray Carpenter takes us to a place upstream from the Kennebec River in Maine, where the federal government ordered the removal of a large dam two decades ago to see what happens when a river is allowed to run free.
MURRAY CARPENTER, BYLINE: Along the Sebasticook River, the first thing you'll notice are the birds. Eagles are everywhere, waiting on gravel bars and chattering from the trees.
(SOUNDBITE OF EAGLES CHATTERING)
STEVE BROOKE: A whole bunch of birds - they're bald eagles. Those are all bald eagles.
CARPENTER: That's conservationist Steve Brooke, who began pushing for dam removals in the 1990s.
BROOKE: As I'm looking down the Sebasticook River, I see a number of bald eagles flying, catching fish from the river to feed themselves and their families.
CARPENTER: When Brooke and others began talking about getting rid of the dam on the Kennebec and another on this tributary, many Mainers didn't see the point. There were hints of the Sebasticook's former productivity - 3,000-year-old fish traps built by the Wabanaki people were found in an upstream lake. But Brooke says many had never seen a large river system in its natural state.
BROOKE: In the Pacific, they're restoring rivers because they still have runs of Pacific salmon. Here on the East Coast, the rivers have been dammed since the 17th century. And so it's very hard for people to understand what's missing.
CARPENTER: Part of what's missing from many Northeast rivers - alewives. The half-pound herring swim up from the ocean to spawn. Now, in some places, it looks like this river is paved with the fish, just like in historical accounts from before the Industrial Revolution.
GAIL WIPPELHAUSER: The expression is you could walk across the river on the backs of fish, and it looks like you could because it's solid fish all the way across and all the way downstream for as far as you can see.
CARPENTER: Gail Wippelhauser is a fisheries biologist with Maine's Department of Marine Resources. She says after the dams came down, fisheries managers helped the fish over dams further upriver, and the alewife population exploded.
WIPPELHAUSER: The increase was just amazing - from 400,000 to, like, a million, then 3 million, 5 million. Just amazing.
CARPENTER: Now the Sebasticook has the nation's largest run of alewives and blueback herring. There's even a commercial harvest, mostly for lobster bait. And other migratory fish are using the river, like striped bass, shad, lamprey and eels.
Dave Scott lives nearby and has fished along the river for 19 years. Sometimes he just puts his rod down and watches.
DAVE SCOTT: Right about two miles from my house is one of the best nature shows. I just come down here to relax sometimes, just to watch the birds fly.
CARPENTER: And there are lots of birds flying. One hundred and ninety eagles were counted along the river in mid-June. Steve Brooke says the Sebasticook shows what could happen elsewhere when other dams come out to bring back free-flowing rivers and wild native fish.
For NPR News, I'm Murray Carpenter in Benton, Maine.
(SOUNDBITE OF TOMMY EMMANUEL'S "THOSE WHO WAIT")
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