Conowingo Dam’s Relicensing is Illegal, Federal Court Rules


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


Zahra Ahmad,, (517) 898-0924

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.

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 that FERC unlawfully issued a new 50-year license for the Dam that did not include any of the environmental protections Maryland’s Department of the Environment had found necessary to protect the Chesapeake Bay and the Susquehanna River.

“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 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 any license for the Dam to include the conditions Maryland finds necessary to achieve the state’s water quality standards. In 2018 Maryland found that many cleanup measures are necessary, including efforts to reduce the Dam’s discharges of nutrients and sediment and measures to maintain and protect downstream habitats and restore declining fish populations.

Because the Dam’s owners have never maintained it, the giant reservoir behind the Dam has been filled with nutrient-laden sediment. When built the reservoir was about 120 feet deep, but now it is only 15 feet deep. During increasingly frequent and severe storm events, that sediment gets scoured from the bottom of the reservoir, washed through the Dam, and discharged in volumes that the River and the Bay cannot handle.

The influx of nutrients from the Dam harms the ecosystems in the River and Bay by creating oxygen-depleted “dead zones” where fish cannot live. The Dam has contributed to an alarming drop in Susquehanna River’s once-teeming American Shad and River Herring populations. These fish used to migrate up the Susquehanna in the millions; now only a few thousand make it each year. The Dam also blocks the passage of eels, an important specie needed for a healthy local ecosystem.

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

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 a 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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