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December 20, 2022

Conowingo Dam’s Relicensing is Illegal, Federal Court Rules

Victory: Millions of tons of pollution pass through the dam into the Susquehanna River and Chesapeake Bay


Zahra Ahmad,, (517) 898-0924

Wahington, D.C.

A federal appeals court today ruled that the Federal Energy Regulatory Commission (FERC) illegally relicensed the operation of the Conowingo Dam on the lower Susquehanna River, in Maryland. As a result, the dam’s owner and operator, Constellation Energy Generation, must implement water quality protections to help wildlife. Before the court’s decision, the dam owner did not have to take the necessary measures to allow fish and eel to pass through to spawn.

The decision comes about a year after environmental groups represented by Earthjustice challenged FERC’s decision to renew the dam’s operation for another 50 years. Groups argued the agency unlawfully renewed Constellation’s license — formerly known as Exelon Corp — as it did not require the company to follow Maryland’s mitigation practices necessary to restore water quality downstream.

“The court threw out a license that would have allowed the Conowingo Dam to catastrophically harm the Chesapeake Bay and the Susquehanna River for another 50 years,” said James Pew, Earthjustice attorney and director of Clean Air Practice. “Maryland must now make the dam’s owner clean up its operations, stop choking the Bay and the River with pollution, and stop blocking the great migrations of fish that are vital to the Bay’s health. It is time to let the bay and the river heal.”

The Susquehanna River and Chesapeake Bay’s water quality have substantially suffered because of sediment and other pollution that gets dragged through the dam and dumped into them. The Clean Water Act requires FERC only to issue a new license if the company includes flows that restore, maintain, and protect downstream habitats and conditions that restore declining fish populations.

Because the dam owner has not kept up with the giant reservoir behind it, it gets filled with millions of tons of sediment and pollution that get dumped into the river and bay during storms. As a result, the reservoir which used to be about 120 feet deep has filled up with pollution and is now only 15 feet deep or less.

The influx of sediment harms the ecosystems in the river and bay. The sediments dumped into them create “dead zones” that cause irreversible harm to their fisheries. The dam has almost decimated the Susquehanna River’s once-teeming populations of American Shad and River Herring. Eels, an important specie needed for a healthy local ecosystem, have also been affected.

Earthjustice represents Waterkeepers Chesapeake, Lower Susquehanna Riverkeeper Association, ShoreRivers, and Chesapeake Bay Foundation.

Quotes from our clients:

“This decision will not only protect the Susquehanna River and the Chesapeake Bay for the next 50 years of this license term but will also ensure that all water quality certifications for large projects can't just be thrown out when it is politically expedient or when the state is pressured to do so,” said Betsy Nicholas, executive director of the Waterkeepers Chesapeake. “This is a big win for the Chesapeake Bay, watermen, downstream residents and the entire Chesapeake Bay clean-up plan.”

“Vacating the unlawful 50-year license for Conowingo Dam which was conspired by the Dam’s owner Constellation Energy and Maryland Department of the Environment sets national precedent in protecting our communities and upholding the statutes of the Clean Water Act,” said Ted Evgeniadis, Lower Susquehanna Riverkeeper. “Our challenge and court ruling sets the record straight in that large corporations do not get a free pass and are held accountable to the law as written.”

“ShoreRivers applauds the Court’s decision to vacate this license and protect our local communities and their fundamental right to clean water. The Eastern Shore bears the brunt of the pollution that flows through the Conowingo Dam, creating navigational hazards, shorelines choked with debris, and oyster bars and underwater grass beds smothered with sediment,” said Sassafras Riverkeeper Zack Kelleher, from ShoreRivers. “We’re happy that the right decision was made in this case for our maritime communities and economy, and to protect all of the restoration work that Marylanders have worked so hard to implement.”

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