There are nearly 3,400 dams in Pennsylvania regulated by the state. Many of those are “low head” dams spanning from one side of a creek or river to the other, affecting the water flow.
“About 75 to 80% of the dams in Pennsylvania are low head dams like this,” Lisa Hollingsworth-Segedy of American Rivers, referring to the Woodland Dam built in 1929 along Little Sewickley Creek in northern Allegheny County.
“The original intent was, it was a swimming pool,” said Eric Chapman of Western Pennsylvania Conservancy, who surveyed fish in the stream with students from nearby Quaker Valley High School from 2009 through 2012.
“It’s the only watershed in Allegheny County, I believe, with naturally reproducing trout in it,” he said. “We found out there’s spotted bass here, which is more of an Ohio [River] main stem species,” Chapman told a group of water experts. He and Hollingsworth-Segedy took a tour group to the former dam site, as part of the Ohio River Basin Alliance conference held recently in Pittsburgh.
However, surveys found that the dam was impacting fish populations.
“We’d have 25 and 30 species downstream of the dam on Woodland and only seven species upstream,” he said.
Because the dam was a barrier to the movement of some fish species, he asked Holligsworth-Segedy, who has worked on more than one hundred dam removals so far in Pennsylvania, to partner with him.
“‘I found a really complicated and horrible dam,’” he told her. “‘Do you want to work on it?’”
She agreed.
They put their money together. He got a grant from the Allegheny Conservation District, and along with funding from American Rivers, they moved forward with the $20,000 project.
The dam was part of the community
Most dam removals take place out of the public view.
“We’re normally in the hinterlands, away from everything,” Chapman said.
But once the permits were in place, the Woodland Dam was removed in full view of a public that had grown up enjoying the waterfall it created and using the pool of water behind it.
“The community felt a communal ownership of this site,” Hollingsworth-Segedy said. “I talked to people at some of the public meetings and they said in the 1950s they would pull their cars into the creek and wash them on Saturday mornings.”
People driving on Woodland Road would roll down their car windows to ask her what would happen to the waterfall.
“First, it’s not a waterfall. It’s an artificial structure,” she told them. “It was definitely a big-time learning, teaching opportunity for the people that really believed that this was something that had been made by nature and was here for their benefit.”
The dam was also dangerous
As Chapman and Holligsworth-Segedy waited for the removal work to begin, they would see kids playing on the dam structure.
“There was rebar sticking out. You could get impinged on it. It was a public safety hazard,” Chapman said.
Hollingsworth-Segedy remembers thinking, ”I can’t believe people are playing on this thing. But that’s what they did. It was their waterfall.”
In July 2015, it took two excavators four days of jackhammering the dam to get it out of the stream.
“The amount of rebar that was in that structure was biblical for the size that it was,” Chapman said. “We had a pile of scrap rebar that was taken out of there, and we took that structure all the way down to the river bottom and took every single piece of concrete out of it.”
A couple of months later, they found new fish species upstream of the dam site, like rainbow darters and smallmouth bass.
But they haven’t heard much from the community,
“Which is generally how it goes,” Hollingsworth-Segedy said. “People are really mad when it happens and then when they realize…”
“The world didn’t come to an end,” Chapman chimed in.
Read more from our partners, The Allegheny Front.
