In settlement with Maryland, Conowingo Dam owner Exelon to invest $200 million to clean up Susquehanna River

Conowingo Dam owner Exelon Corp. and the state of Maryland have reached a settlement under which the Chicago-based energy company will invest $200 million to clean up the Susquehanna River, and, by extension, the Chesapeake Bay.

That includes $41 million to reduce the amount of trash and debris passing through the dam toward the bay, $47 million for projects to increase populations of grasses and oysters and $500,000 to study how to deal with sediment built up behind the dam.


The company and Gov. Larry Hogan’s administration had been at odds over Exelon’s management of the flow through the dam after record rainfall across the Mid-Atlantic in 2018 sent a surge of debris downstream into the bay.

Even before that, they had long discussed what to do to reduce sediment and nitrogen pollution reaching the Chesapeake because the dam has reached its capacity for trapping that material. Exelon sued Maryland last year after environmental officials issued the Conowingo a new water quality permit that demanded the company do more to reduce pollution passing through the dam. The company argued it should not be held responsible for pollution it does not create.


The Conowingo and Susquehanna are a pressing concern for environmentalists because the river provides most of the fresh water in Maryland’s portions of the bay, and also carries massive amounts of nitrogen, phosphorus and sediment pollution that foul Chesapeake ecosystems. Since its construction in 1928, spanning Harford and Cecil counties about 10 miles upstream of where the Susquehanna meets the bay, the dam has prevented much of that pollution from reaching the bay.

Hogan administration officials said the agreement would do much to protect the bay and advance progress toward a 2025 goal to restore the health of the estuary.

“This agreement charts a bold course for clean water and climate resiliency in the Susquehanna River and Chesapeake Bay,” state Environment Secretary Ben Grumbles said in a statement.

Exelon officials confirmed that the settlement resolves their lawsuit, though they added that it must be approved by the Federal Energy Regulatory Commission. FERC is soon expected to begin reviewing an application for the Conowingo’s next 50-year operating license. Maryland had sought to impose the stricter environmental requirements on Exelon as part of that process.

“This agreement charts a bold course for clean water and climate resiliency in the Susquehanna River and Chesapeake Bay.”

—  Ben Grumbles, Maryland environment secretary

CEO Chris Crane said the investment, which will come from the dam’s earnings over the anticipated life of that FERC license, would "substantially improve water quality while ensuring Maryland’s largest source of renewable energy continues to deliver environmental and economic benefits for the next generation.”

“This is a victory for clean energy and the long-term preservation of the Chesapeake Bay," he said in a statement.

Environmental groups agreed that the settlement could promote a healthier bay, though some expressed concern about how it would be enforced.

Chesapeake Conservancy CEO Joel Dunn praised it for including investment in upstream ecosystems and focusing on preventing pollution from reaching the bay in the first place.


Waterkeepers Chesapeake Executive Director Betsy Nicholas said she was pleased to see the deal calls for investment in eel and mussel populations, both species that have suffered since the dam has blocked upstream access.

However, Alison Prost, Maryland executive director of the Chesapeake Bay Foundation, said she thinks the investments aren’t enough to offset the dam’s impact on water quality. She said Exelon should focus on “significant environmental improvements upstream” of the Conowingo.

Nicholas said she is also concerned that the deal does not set aside enough money to deal with the risk of a hurricane or other major rainstorm washing out a large amount of the sediment and nitrogen trapped behind the dam. Waterkeepers Chesapeake and the Lower Susquehanna Riverkeeper appealed the state Conowingo permit last year because of those concerns, and Nicholas said that petition is remains pending despite the settlement.

“At no point in this process have we seen anything that would really address that threat,” she said.

Grumbles said the agreement includes $250,000 a year to monitor the scouring of material from behind the dam, providing information that could show how best to address concerns about the sediment and nitrogen polluting downstream waterways.

While groups including Waterkeepers Chesapeake, the Chesapeake Bay Foundation and the Nature Conservancy have been formally involved in the dam’s license renewal process, they are not a party to the settlement, Nicholas said. They also have no power to make sure the money Exelon is committing to various programs will be spent on those initiatives; the agreement calls for the company to deposit the money into the state’s Clean Water Fund, a pot of money the state uses for environmental projects around Maryland.


“As groups who consider ourselves sort of watchdogs on industry and government, we’d like to have some enforceable power,” Nicholas said.

Grumbles said the state, as well as FERC, would hold Exelon to its commitments.

“It’s an enforceable contract,” he said.