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Hogan Administration Announces Significant Progress on Conowingo Dam

Includes Multi-State Strategy, Bidder for Dredging Pilot Project

ANNAPOLIS, MD – The Hogan administration today announced that Maryland has made significant progress toward solving environmental problems stemming from the Conowingo Dam on the Susquehanna River. This progress includes the U.S. Environmental Protection Agency’s (EPA) recognition of the Conowingo Watershed Implementation Plan multi-state strategy and plan to hire a third-party fundraiser and project coordinator; and Maryland’s selection of a winning bidder to carry out a pilot project for dredging, beneficial reuse, and testing of sediment behind the dam.

These steps – along with a comprehensive set of environmental protection requirements issued by the Hogan administration to Exelon Corporation as conditions for the company relicensing the dam – encompass the Hogan administration’s multi-pronged, multi-state, public-private strategy to address water pollution issues associated with the Conowingo Dam.

“From the beginning of our administration, we have warned of the risks posed by debris and pollution flowing down the Susquehanna River and over the Conowingo Dam,” said Governor Larry Hogan, who chairs the Chesapeake Executive Council regional commission. “Now, through our consistent efforts to address this issue, we are making measurable and real progress in our efforts to reduce pollution and preserve our Chesapeake Bay for future generations.”

“Maryland’s holistic strategy on the Conowingo Dam is a smart way to restore the Chesapeake Bay,” said Maryland Environment Secretary Ben Grumbles. “With a cleanup plan specific to the Conowingo Dam, dredging that provides materials for beneficial reuse, and an environmental plan for the dam’s relicensing that includes stringent environmental conditions, we can help launch a restoration economy and restore the Bay.”

The presence of any dam, including the Conowingo Dam, influences the flow and conditions of a waterway in ways that impact its ability to naturally transport and process sediment and associated nutrients that can negatively affect water quality. For many years, the Conowingo Dam improved water quality in the lower Susquehanna River and Chesapeake Bay by trapping sediment that can contain nutrients. However, because the reservoir has reached capacity, the dam is no longer acting as a trap. This leads to additional nutrients – nitrogen and phosphorus that in the past would have been trapped by the dam – entering the Bay.


Maryland and the other Chesapeake Bay watershed states are several years into the implementation of federally required state-by-state plans to collectively reduce water pollution and restore the Chesapeake Bay. Last year, the Chesapeake Bay Program partnership unanimously agreed on the need to develop an additional plan – known as the Conowingo Watershed Implementation Plan (WIP) – to specifically reduce pollution associated with the loss of the Conowingo Dam’s capacity to trap sediment in the reservoir behind the dam. Secretary Grumbles, as chair of the Bay Program’s Principals’ Staff Committee, has played an active role on behalf of the Governor’s Chesapeake Bay Cabinet to ensure progress is being made in developing a collaborative Conowingo WIP that engages all of the states and the federal government.

A key step was taken when the EPA issued a Request for Applications (RFA) for work on the Conowingo WIP. The EPA plans to award one to three cooperative agreements for work that will support the efforts of the watershed jurisdictions, along with other partners, to help restore the Bay. The work proposed by the RFA includes facilitating the development and implementation of a Conowingo WIP, the development of a comprehensive financing strategy and implementation plan, and the development of a system for tracking, verifying, and reporting the results of the WIP. A scientific analysis shows an additional reduction of six million pounds of nitrogen and 260,000 pounds of phosphorus is needed to mitigate the water quality effects of the dam’s lost trapping capacity. Science has demonstrated that this lost trapping capacity severely threatens the state’s and region’s ability to meet Chesapeake Bay cleanup goals.


The Maryland Environmental Service (MES), in coordination with MDE and the Governor’s Bay Cabinet, has selected Northgate Dutra JV to carry out a $3 million pilot project to test the quality of sediment throughout the Conowingo reservoir and to dredge and beneficially reuse a small portion of it to create a market for cost-effective recovery of material that has greater value on the land than as a threat to water quality in the river or Bay.

The proposed pilot project schedule provides for the work to be substantially complete in 2019. The pilot project will be fully funded by the Maryland Department of the Environment.

“MES is committed to expeditiously moving this pilot project forward utilizing innovative solutions for preserving and enhancing the health of the Bay,” said MES Director and CEO Roy McGrath. “The project will aid in identifying and ultimately reducing contaminants in the reservoir behind the hydroelectric dam, preventing those from flowing downstream, and leading to continued improvements in water quality throughout the Chesapeake Bay watershed.”


Exelon is seeking a 50-year federal license renewal for the dam’s operation. Under federal law, and as part of the Federal Energy Regulatory Commission’s relicensing process, Exelon is required to obtain a Clean Water Act, Section 401 Water Quality Certification from the state for the continued operation of the dam. The certificate enforces the requirement that the facility’s operation comply with state water quality standards.

In 2018, the Hogan administration issued a comprehensive environmental plan for the Conowingo Dam, Susquehanna River, and Chesapeake Bay to drive major restoration and pollution prevention efforts upstream and downstream of the dam. The plan, contained in a Water Quality Certification issued by MDE, includes special conditions for the proposed dam relicensing and requires the applicant, Exelon Generation Company LLC, to reduce water pollution that flows from the dam to the river and, eventually, the Bay.

The certification also requires Exelon to improve conditions for aquatic life, including changes in its control of water flow from the dam and installation of equipment to improve migration of fish to upstream spawning areas. It also requires Exelon to improve its management of debris that collects at the dam, including conducting a feasibility study on a solar-powered trash collection wheel.

Maryland is vigorously defending this science-based and federally enforceable plan in the face of challenges from Exelon. In October, the Circuit Court for Baltimore City dismissed Exelon’s challenge there (although Exelon is appealing the dismissal). Exelon’s request that MDE reconsider the issuance of the Water Quality Certification is also pending with the department. MDE has filed a motion to dismiss a complaint filed by Exelon in U.S. District Court.


The Hogan administration fully funded all Chesapeake Bay restoration efforts for four years in a row, investing a record $5 billion, and earlier this year proposed a fifth year of major funding for the Bay. As chairman of the Chesapeake Executive Council, Governor Hogan has led the fight to protect and restore federal funding for the Bay. Governor Hogan has also stated his intention to continue to push the upstream states of Pennsylvania and New York to do their fair share to protect the Bay.


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