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Maryland Department of the Environment

Hogan administration issues comprehensive environmental plan for Conowingo Dam, Susquehanna River, Chesapeake Bay


Jay Apperson

(410) 537-3003

Hogan administration issues comprehensive environmental plan for Conowingo Dam, Susquehanna River, Chesapeake Bay

Newly issued Water Quality Certification for dam will drive major restoration and pollution prevention efforts upstream and downstream to benefit the river and Bay

BALTIMORE, MD (April 27, 2018) – The Maryland Department of the Environment today issued a Water Quality Certification with special conditions for the proposed relicensing of the Conowingo Dam. As part of a comprehensive strategy for Chesapeake Bay restoration, the certification requires the applicant, Exelon Generation Company LLC, to reduce water pollution that flows from the dam to the lower Susquehanna River and, eventually, the Bay.

The certification also requires Exelon to take several steps to reduce sediment and nutrient pollution and 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.

Science has demonstrated that the Conowingo Dam has lost its capacity to trap sediment and nutrient pollution, which severely threatens the state’s and region’s ability to meet  Chesapeake Bay cleanup goals. The Water Quality Certification, developed in partnership with the Maryland Department of Natural Resources, is part of a comprehensive strategy and regional approach to find solutions and ensure progress in Bay restoration.

“Maryland has taken bold, decisive action to reduce pollution in  the Chesapeake Bay and we are making tremendous progress, but all of our progress could be at risk if we do not pursue a comprehensive regional approach to reducing pollution in the Susquehanna River,” said Governor Larry Hogan. “From the beginning of our administration we have sounded the warning on the problems caused by the Conowingo Dam. This certification provides a strong framework for working with the upstream states and private partners such as Exelon to take real actions to address  the sediment and nutrient pollution problems caused by the dam so we can preserve the Bay for future generations.”

“The stringent environmental conditions in the certification are at the heart of a comprehensive strategy to speed up the cleanup of the Bay and hold our partners accountable for doing their part to create a healthier watershed. This water quality certification, based on sound science and law, includes responsible and necessary conditions for pollution prevention and continued progress for the Susquehanna River and the Chesapeake Bay,” said Maryland Environment Secretary Ben Grumbles. “This water quality certification is part of a holistic approach, working with Exelon and our fellow watershed states, to meet our Bay restoration goals and help launch a restoration economy.”

Since identifying sediment pollution flowing down the Susquehanna as a critical impediment to Bay restoration progress during his campaign for governor, Governor Hogan has convened two Conowingo Dam summit meetings to discuss solutions to the facility’s growing threat to the Bay. Following the second summit meeting, the Hogan administration launched a pilot project to dredge behind the dam and develop beneficial reuses for the dredged material. The dam’s effect on water quality is also a key element in the midpoint assessment of the multi-state Chesapeake Bay Total Maximum Load (TMDL), or pollution diet, and associated Watershed Implementation Plans (WIPs).

Governor Hogan serves as chair of the Chesapeake Executive Council of the Chesapeake Bay Program, which establishes the policy direction for the restoration and protection of the Bay. In March, consensus was reached on developing a separate Watershed Implementation Plan (WIP) to address the Conowingo. This summer, the Governor will reconvene the Chesapeake Executive Council to further discussions on the Conowingo WIP and other critical Chesapeake Bay initiatives.

The Conowingo Dam: water quality and relicensing

The presence of any dam, including the Conowingo Dam, influences the flow and conditions of a waterway in ways that affect its ability to naturally transport and process sediment and associated nutrients. 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.

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 Maryland Department of the Environment for the continued operation of the dam. The certificate enforces the requirement that the facility’s operation comply with state water quality standards.

In 2014, in response to Exelon’s initial application for a water quality certification, MDE stated its intent to deny the application due to insufficient information provided by the applicant regarding the water quality impacts of the proposed activity. In recognition of that position, Exelon withdrew its application and agreed to provide up to $3.5 million for further study of the effects of sediment and associated nutrients on the water quality of the lower Susquehanna River and the Chesapeake Bay.

In May 2017, Exelon submitted the current application for Water Quality Certification for the dam’s relicensing. As part of its review, MDE, in close coordination with the Maryland Department of Natural Resources and other agencies, identified all applicable water quality standards and requirements and utilized data, modeling and further scientific analysis, along with materials provided by Exelon and information provided in public comments.

MDE sought to find a constructive solution to the challenges at Conowingo Dam by working together with Exelon, but recently concluded that it is unrealistic for the department and the company to reach a negotiated settlement regarding the water quality certificate prior to the May 17, 2018, deadline, as mandated under the Clean Water Act, for a state response to the application.

The certification’s nutrient reduction requirements

The certification establishes a requirement, based on the Clean Water Act, for Exelon to reduce nutrient pollution in amounts equal to what had previously been trapped by the dam. A scientific analysis shows those amounts to be six million pounds of nitrogen and 260,000 pounds of phosphorus a year. Exelon will be required to develop a sediment and nutrient management plan to meet its obligation.

Recognizing the constant challenges posed by upstream pollution flowing down the river, the certification also includes a provision under which Bay watershed states will also make reductions.  Under the terms of the certification, the reductions required of Exelon would be reduced by the amount of reductions made by bay watershed states under the new Conowingo WIP. The Bay watershed states have agreed to work together, along with Exelon, to achieve water pollution reductions needed to account for the additional pollution resulting from the loss of the dam’s trapping capacity. Those reductions by the states are to be in addition to the reductions each state is already required to make under their pollution reduction plans.

Improving conditions for aquatic life

Exelon controls the flow of water from the Conowingo Dam. The dam’s operation causes unnatural flows of water downstream, adversely affecting migratory fish such as the American shad, river herring and American eel, as well as habitat for mussels and other aquatic life. The certification requires Exelon to implement its proposed changes in flow to improve conditions for downstream aquatic life and increase fish migration upstream. It would also allow Exelon 10 years to study flow, at which time Exelon would be required to implement a more natural flow regime, as proposed by the Susquehanna River Basin Commission and the Nature Conservancy and supported by the Chesapeake Bay Foundation and Midshore Riverkeeper Conservancy, unless Exelon can show that some or all of those provisions will not provide significant benefits to migratory fish and other aquatic life.

The certification also requires Exelon to build an additional eel passage facility at the dam and comply with provisions for restoring migratory fisheries contained in a prior fish passage agreement. The Department of Natural Resources will play a key role in overseeing the implementation of provisions to improve conditions for aquatic life and migratory fish passage.

Debris and other conditions

The certification requires Exelon to improve its operation to remove debris, which threatens recreational use of the reservoir for boating and fishing as well as recreational uses and clean water supplies downstream after a large storm. Under terms of the certification, Exelon must more frequently remove debris and must conduct a study on the feasibility of installing and operating a solar-powered trash collection wheel, similar to those used in the Baltimore Harbor.

The Hogan administration and the Chesapeake Bay

Governor Hogan’s fiscal year 2019 budget invests a record $1.2 billion in state funds toward wide-ranging Chesapeake Bay restoration efforts, continuing the Hogan administration’s commitment to protecting Maryland’s most precious natural asset. With more than $4 billion toward restoration efforts since taking office, no administration in state history has invested more in its first four years.

The record levels of funding for key Chesapeake Bay conservation and regulatory innovation programs includes $52.9 million for the Chesapeake and Atlantic Coastal Bays Trust Fund​, marking the third year in a row that the Hogan administration has fully funded Bay restoration efforts​. The fiscal year 2019 budget marks the first time since 2008 that no funding for transfer tax programs, including Program Open Space, is diverted to the General Fund. In total, these programs receive $253 million, an increase of $67 million from the prior fiscal year.

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