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MD's Agreement On Conowingo Dam Fails To Address Sediment Pollution Problem

Tom Pelton

In North Central Maryland, near the base of the Conowingo hydroelectric dam on the Susquehanna River, a small group of protesters rallied on Friday. They were complaining about an agreement that the dam’s owners, the Exelon Corporation, recently signed with Maryland Governor Larry Hogan’s Administration.

The protesters’ signs read, “Don’t let Exelon off the hook!” and, “We all live downstream.”

Ted Evgeniadis is the Lower Susquehanna Riverkeeper, a nonprofit clean water advocacy group that organized the event. “The reservoir is at capacity, and as it stands now, the dam is a ticking time bomb toward the Chesapeake Bay,” he said.

His group is urging the Federal Energy Regulatory Commission to reject a proposed relicensing of the 92-year old dam for another half century. Evgeniadis’ main concern is that Maryland’s agreement with Exelon – which would allow the relicensing -- does nothing to solve the biggest problem with the dam. Over the decades, millions of tons of tons of sediment and pollution have built up behind the dam, and the muck keep getting flushed downriver into the Chesapeake Bay during big storms.

“I believe Exelon has a responsibility to remove that sediment,” Evgeniadis said. “A river’s job is to transport sediment.  During any given time, reservoirs behind dams will fill.  And here we are, all hydroelectric dams on the lower Susquehanna River are full of sediment and something needs to be done about it.”

When Governor Hogan ran for election in 2014, he made a big deal about the sediment behind the Conowingo Dam. Back then, Hogan said he would oppose granting Exelon a long-term renewal of its license unless it agreed to help remove the sediment, perhaps by dredging.

But the agreement signed by the Hogan’s Administration and Exelon on October 29 does nothing to require the company to remove the sediment by dredging or by any other means.  Instead, the agreement merely requires Exelon to pay for a $500,000 feasibility study of what could potentially be done with the sediment. The company would also pay millions of dollars for a variety of other environmental projects – such as the planting of bay grasses, clams, oysters and trees along streams on farms to reduce runoff.

Here’s Hogan’s environmental secretary, Ben Grumbles.

“We believe that the settlement that we reached with Exelon is historic. It’s a $200 million investment in holistic river and watershed improvements,” Grumbles said. “But it’s certainly not enough by itself. We really need the states of Pennsylvania and New York to step up.”

Much of the sediment and pollution behind the dam comes from farms in Pennsylvania, and Pennsylvania lawmakers have been negligent about --and even hostile to -- the regulation of agriculture.

Kathleen Barron, a senior vice president at Exelon, argues that dredging behind the dam could hurt the bay by stirring up more sediment.

“What you have to think about is – if you were to talk about taking that sediment out from behind the dam – is not just the cost of it – which would be prohibitive – but also the environmental costs,” Barron said. “And the US Army Corps has done a study examining what that would mean to the water downstream and the bay and they have concluded that dredging would increase sediment at an environmental cost 10 times greater than any potential benefit.”

However, that’s not really the conclusion of the Army Corps study she referred to.  That 2015 study, titled the “Lower Susquehanna River Watershed Assessment,” said that dredging the sediment from behind the dam would likely produce small but short-lived ecological benefits to the Chesapeake Bay.

The Army Corps of Engineers and partners concluded that, even after dredging, some sediment would still be flushed over the dam during big storms, but in lesser amounts than today.

With a lack of even that small step forward – a requirement for dredging behind the Conowingo -- the bay’s biggest dam problem remains as murky today as it was before Governor Hogan was elected.

Tom Pelton, a national award-winning environmental journalist, has hosted "The Environment in Focus" since 2007. He also works as director of communications for the Environmental Integrity Project, a non-profit organization dedicated to holding polluters and governments accountable to protect public health. From 1997 until 2008, he was a journalist for The Baltimore Sun, where he was twice named one of the best environmental reporters in America by the Society of Environmental Journalists.