Pennsylvania's aggressive dam removal program questioned

Photo Copyright 2008 by Sofia Lareau

The Conewango Dam will be scheduled for demolition next year if the Pennsylvania Department of Environmental Protection can obtain a permit from the U.S. Army Corps of Engineers.

However, recent research by two Pennsylvania scientists suggests that removal of dams like this one could actually cause environmental damage.

The Conewango Dam in downtown Warren, which has been present in some form for a century and a half, is scheduled for removal this summer by the Pennsylvania Department of Conservation and Natural Resources.

The state's program to remove "orphaned" mill dams across Pennsylvania has had great success in restoring waterways, allowing fish to swim upstream and increasing access to boaters and canoers. The mill dams that fill the commonwealth are a legacy of the state's timber and mill industries, that no longer use the waterways.

In Warren County, which once had the largest lumberyard east of the Mississippi, the Conewango Dam and its variations were used to power a mill and to collect timber prior to assembly as giant rafts to float downstream to Pittsburgh. Those days are gone, but local residents who have grown up with the Conewango Dam have become accustomed to its appearance and the charm it bestows in the middle of town just upstream from the confluence of the Allegheny River and the Conewango Creek.

Efforts to save the dam were approved, at least informally, by members of the City Council recently, but there is no money to pay for insurance and maintenance, although no work has been done on the dam in recent memory and there is no record known of a death caused by the structure.

Now, two Pennsylvania scientists think removal of the ancient mill dams may paradoxically contribute to waterway pollution. Each dam holds back huge amounts of silt which, once released, alter the chemistry of a waterway once the dam is removed. The sediment is nutrient rich with high concentrations of phosphates which can be harmful to a local eco-system. It could take many, many years for local flora and fauna to recover from the removal of a dam, according to the scientists.

The recent discovery was written up in the New York Times and a paper on the ecology of mill dams  was published in Science on January 18 of this year.

see related editorial: Nuke the whales and save the dam

--Chris Lareau

Comments

[Fred]

Nuke the Whales!

...and save the dam.