How Demolishing Dams in Connecticut Restores Rivers and Wildlife | Connecticut Public Radio
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How Demolishing Dams in Connecticut Restores Rivers and Wildlife

Oct 13, 2015

Removing old dams is sometimes a tough sell.

Follow a stream in Connecticut and eventually, you're likely to encounter a dam.

Before electricity, dams across Connecticut provided power for places like mills. Today these remnants of our industrial past serve largely aesthetic functions -- if any purpose at all. And a group of state and federal organizations are using storm resiliency money to remove these dams and reduce flooding risks. 

Sally Harold works on river restoration projects for the Nature Conservancy. One of those projects is the Ed Bills Pond Dam, on the eastern side of the Eight Mile River in Lyme. 

"There are over 4,000 dams in Connecticut streams, so they're very, very dense.  There are very few streams that we could name that have no dams," Harold said.

Ed Bills is an 80-year-old dam. It's a small concrete and stone barrier holding back a large pond of water. But there's something peculiar about this dam -- part of it's missing. In the center, a notch about three or four feet wide has been removed, and water is slowly trickling through.

“If you imagine that the impoundment or the pond behind the dam is like a big bucket of water -- you don't want to release that all at once,” Harold said.   

Ed Bills Pond in Lyme, Connecticut.
Credit Ryan Caron King / WNPR

While the dam comes down, engineers have installed a temporary stone 'check dam' behind the old one. It's basically a big pile of gravel that can be shifted around to filter water and control flow levels.

“We have to find a way to control that slowly -- so that we're draining the pond slowly. It allows us an opportunity to collect mussels and fish. Other organisms that might be living in the pond -- so that we're not leaving them high and dry,” Harold said. 

Amy Singler works for American Rivers. She said many of Connecticut's 4,000 dams are privately owned. And while removing old dams removes barriers to migrating fish like river herring, American shad and eel ---- getting rid of them can radically change how a property looks. So, sometimes, its a tough sell.

“It's a lot to say 'Take our word for it,' because what we're saying is -- is it's going to look fundamentally different than what it looks like now,” Singler said. 

Amy Singler of American Rivers at the site of the White Rock Dam removal project.
Credit Ryan Caron King / WNPR

Fortunately, she said --- that wasn't the case here. Ed Bills Pond Dam removal will cost about $600,000, but she said the private landowner was all for it. Both for high-minded things like "conservation" and more practical concerns like liability.

“The most obvious one is the potential for the dam to fail -- either just during regular storm events or, increasingly, during some of the high flow events that we're getting,” Singler said. 

Sally Harold works on river restoration projects for the Nature Conservancy.
Credit Ryan Caron King / WNPR
"We are actually returning the river to its historic channel."
Sally Harold

And lately, there's been a lot of federal money to back this up. About $170 million was set aside for the U.S. Fish and Wildlife Service following Hurricane Sandy for recovery and resiliency projects -- including about $2 million, some of which will be used for the White Rock Dam in Stonington.

At the site of the White Rock Dam last Thursday afternoon, a water pump hummed along as engineers zipped around the site, sizing up large stones and trying to determine how they'll impact river flow once river water pours back into its natural channel.

The 113-foot concrete dam that used to stretch across the Pawcatuck River was removed. In its place is a temporary barrier redirecting river flow down a man-made channel that runs parallel to where the river used to flow

Decades ago, the water flowing through the man-made channel powered a mill. “But fish couldn't go up that channel because the water velocity was too strong,” Harold said. 

And ultimately, the goal will be to have the water flow down the original, natural channel. In a few weeks, once the temporary barrier comes down, water will flow over the ground on which the engineers stood. 

The dam removal site at the White Rock Dam in Stonington, Connecticut.
Credit Ryan Caron King / WNPR

The dam removal site at the White Rock Dam in Stonington, Connecticut.
Credit Ryan Caron King / WNPR

“Essentially this was a dry riverbed. Very little flow went down. So we are actually returning the river to its historic channel,” Harold said. 

Harold said some stones will stay in place. Others will be moved to create shaded, deeper, pools — a helpful diversity of habitat for river animals.

And that man-made channel will stay in place, too, to catch overflow during heavy storms.

Harold said the White Rock project should be completed in late November. As to how the river will flow when the dams are gone and the natural riverbed is restored: “This time of year, it looks like a lazy river -- it would be a nice paddle,” Harold said. 

And yes, when it's done, Harold said she'll paddle it -- enjoying one more Connecticut river, blocked by one less dam.