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Conowingo Hydroelectric Generating Station

An Engineering Feat of Hydroelectric Power

The Conowingo Dam was an engineering marvel when constructed nearly a century ago, and it continues to operate safely and reliably today. Located on the lower Susquehanna River in northern Maryland, Conowingo has served as Maryland’s largest source of renewable energy since it began operation in 1928. Owned and operated by Constellation, the Conowingo Dam currently has 11 turbines, which can produce up to 572 megawatts (MW) of electricity. Over the years, the Conowingo Dam has played an important role in protecting the Chesapeake Bay, supporting local and state economies, and providing recreational opportunities for thousands of local residents and tourists.

The dam also has a visitors center where the public can learn about the history of Conowingo, the role of hydroelectricity as a renewable energy source, and about nearby recreational facilities and public access areas available for residents and tourists. These recreational activities include birdwatching, picnics, photography and more. Constellation maintains several public parks as part of its Conowingo license and welcomes thousands of visitors eager to learn about local ecology every year.

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About This Facility

Darlington, Maryland 21034

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Constellation received a 50-year license from the Federal Energy Regulatory Commission (FERC) on March 19, 2021 to continue operating the Conowingo Dam. The license is a critical step forward for Chesapeake Bay restoration efforts and paves the way for long-term investments that will enhance water quality, fish and eel passage, aquatic habitats and debris removal. It also enables the continued operation of Maryland’s largest source of renewable energy, which generates safe, reliable power for tens of thousands of families and businesses in the state.

Conowingo Dam Crest Gates​

To comply with Federal Energy Regulatory Commission (FERC) requirements, we open the dam's crest gates when river conditions require. We are committed to continually informing and working with community and government partners to fulfill our shared responsibility to protect and restore the health of the bay.

Constructed in 1928, the Conowingo Dam originally produced 252 megawatts (MW) of power, becoming the second-largest hydroelectric project in the United States after Niagara Falls. Today, the dam includes 11 turbines and can generate up to 572 MW of pollution-free electricity, powering 165,000 homes, on average. In fact, the dam's renewable energy production is greater than all other Maryland renewable energy sources combined.

The dam is also a critical player in meeting the state’s renewable energy and climate action goals and prevents 867,000 metric tons of greenhouse gas emissions each year, the equivalent of taking 186,000 cars off the road.

In addition to powering homes and businesses, the Conowingo Dam produces economic and environmental benefits for both the state and local communities throughout the region.

In October 2019, the State of Maryland and Constellation reached a historic agreement that will help protect the Chesapeake Bay for decades to come. Read more about the full agreement. 

As a part of Maryland’s vital energy infrastructure, the Conowingo Dam provides $273 million in economic benefits every year, which includes supporting 265 full-time equivalent jobs, paying $10 million in annual state and local taxes, and attracting 365,000 recreational visits annually. As a major tourist site in eastern Maryland, the Conowingo Dam and recreation area contribute to Cecil and Harford Counties’ $21.7 million in tax revenue from tourism in 2018. The Conowingo Pond, located behind the dam, is vital to the water supply for several communities, serving as a back-up water supply source for both the City of Baltimore and the Chester Water Authority.

With more than a dozen community events every year, Constellation is proud to be involved with several charitable activities and non-profit organizations committed to Maryland and the Chesapeake Bay. Our employees proudly participate in a variety of charitable activities, such as donations to the local United Way chapters, the Boys and Girls Clubs of Cecil and Harford Counties, the Harford Family House, the Stroud Water Research Center, and the Plumpton Park Zoological Gardens, Inc., among others. 

We share the State of Maryland’s commitment to restoring and sustaining the health of the Chesapeake Bay. That's why in October 2019, the State of Maryland and Constellation reached a historic agreement that will help protect the Chesapeake Bay for decades to come. The benefits to Maryland and the Chesapeake Bay are valued at more than $200 million over the anticipated 50-year life of the license, which will be funded from the dam’s earnings over that time period. These funds will be used to address key issues facing the bay, including upstream debris, fish and eel passage, nutrient reduction, mussel restoration, and resiliency initiatives.

Read more about the full agreement and all of the benefits for the Chesapeake Bay. 

 

Protecting Our Waterways

One of the key environmental issues for the Chesapeake Bay is debris. Debris originates upstream from the more than 27,500 miles of tributaries and streams in the Susquehanna River watershed, flowing down through New York, Pennsylvania, and Maryland. Our agreement with the U.S. Department of Interior also includes significant investments in fish passage improvements at the dam and the creation or re-introduction of a trap-and-transport program to transport fish from Conowingo Dam to north of the York Haven Dam. In addition, Constellation will fund a total of $11 million for improvements to eel passage and to benefit nutrient reductions and aquatic habitats, plus $1 million to fund eel passage research.

To comply with Federal Energy Regulatory Commission (FERC) requirements, we open the Conowingo Dam's crest gates when river conditions require. We are committed to continually informing and working with community and government partners to fulfill our shared responsibility to protect and restore the health of the bay.

Constellation uses a variety of tools and resources to help remove the debris safely and efficiently, including:

  • Deploying crews to operate overhead cranes and grapple devices
  • Launching debris skimmer boats to assist with clean up
  • Sponsoring two major annual events: the Lower Susquehanna Heritage River Sweep and Conowingo Pond clean-up day, where we remove 600 tons of debris and refuse from the river each year
  • Supporting other groups also focused on bay clean-up efforts, as with our $25,000 donation in 2018 to the Chesapeake Bay Trust to support local debris clean-up efforts after a severe flooding event

Through these efforts, we removed more than 4,000 tons of debris in 2018 alone. Although Constellation voluntarily removes debris from the river, it is not possible to remove all debris flowing toward the dam from the upstream watershed. This is especially true during flood conditions, as seen during the summer of 2018 when the Susquehanna River swelled to 10 times its normal level.

 

Protecting Our Wildlife

The Conowingo Dam continues to play an instrumental role in wildlife conservation. In the early 1990s, a $12 million fish lift was completed at the dam, which has restored more than 1 million American shad, returning them to the upper Susquehanna River and supporting local recreational fishing. Moreover, 300 American bald eagles gather at the Conowingo Dam annually by Thanksgiving, which they use as a major breeding, nesting, and foraging ground.

  • Located on the Susquehanna River in northern Maryland, the Conowingo Dam is the largest source of renewable energy in the State of Maryland.
  • The Conowingo Dam can generate up to 572 megawatts (MW) of power. In average operating conditions, the Conowingo Dam produces enough power to supply 165,000 homes.
  • Because water is used to turn the turbines, Conowingo can be used to "jump start" the electric distribution system in the event the connection to the regional grid experiences a failure.
  • The Conowingo Pond, which is created by the dam holding back the water of the Susquehanna River, is used as a public water supply source for the City of Baltimore and Chester Water Authority (CWA).
  • Conowingo supports local residents and business throughout the region with substantial contributions to local and regional economies and the recreational opportunities it provides for thousands of residents each year.

To comply with Federal Energy Regulatory Commission (FERC) requirements, we open the dam's crest gates when river conditions require.

No, the Conowingo Dam does not produce any pollution.

  • Constellation voluntarily removes an average of 600 tons of trash and debris around the dam each year.
  • We deploy crews to operate overhead cranes and grapple devices to clear debris from the river as safely and efficiently as possible.
  • When safe, we will also launch debris skimmer boats to assist with cleanup.
  • Although Constellation voluntarily removes debris from the river, no one can remove all debris from the upstream watershed, especially during flood conditions.

Debris originates upstream from the more than 27,500 miles of tributaries and streams in the Susquehanna River watershed, which flows across New York, Pennsylvania, and Maryland.

In October 2019, the State of Maryland and Constellation reached a historic agreement that will help protect the Chesapeake Bay for decades to come.

In keeping with our strong track record of environmental stewardship, we will contribute more than $200 million from the Conowingo Dam’s operation over the next 50 years to address key issues facing the bay, including upstream debris, fish and eel passage, nutrient reduction, mussel restoration and resiliency initiatives. Specifically, the $200 million in contributions to restore and sustain the Chesapeake Bay include the following initiatives:

 

Restoration and Protection of the Chesapeake Bay

  • A contribution of Constellation lands and more than $25 million in funding to support the construction, operations, and maintenance of a mussel hatchery along the banks of the Susquehanna River. Mussels from this hatchery when stocked into the Susquehanna River basin will filter nutrients and sediment before they reach the Chesapeake Bay. This natural improvement in water quality will be further enhanced by increasing passage of an important mussel host species, American eel, at the Conowingo Dam.
  • More than $19 million of funding support for Maryland to invest in water quality improvement projects, including forest buffers and agricultural projects such as cover crops to reduce nutrient pollution.
  • More than $12 million to Maryland to support staff resources for oversight and protection of the Chesapeake Bay.
  • $5 million for chlorophyll A monitoring and reporting.
  • $500,000 to fund a feasibility study of dredge material disposal options in and around the Conowingo pond.

 

Enhanced Debris Management

 Continued commitments valued at $41 million to address debris accumulation, including an engineering study examining additional methods to divert debris before it reaches the dam, and employment of clamming, skimming, or other equally effective means of debris removal.

 

Enhanced Habitat and Fish Passage Improvements

  • $11 million of improvements to eel passage that will help facilitate mussel restoration, plus a contribution of $1 million to fund eel passage research.
  • More than $47 million in funding for climate resiliency projects, including submerged aquatic vegetation, aquaculture, clam and oyster restoration projects, and living shoreline creation to help make the Susquehanna River and Chesapeake Bay more resilient to severe weather events. 
  • Modifications to river flow valued at $52 million to enhance habitat for aquatic species like American shad and river herring, which reside downstream of the dam, and submerged aquatic vegetation, which trap sediment, remove pollution, and serve as a vital habitat for spawning and rearing fish.

 

Read more about the full terms of the agreement. 

  • Every year, the Conowingo Dam provides $273 million in economic benefits to Maryland and its local communities.
  • The dam and its employees participate in a variety of charitable activities, such as donations to the local United Way chapters, the Boys and Girls Clubs of Cecil and Harford Counties, the Harford Family House, the Stroud Water Research Center, and the Plumpton Park Zoological Gardens, Inc., among others.
  • The dam also serves as a major source of educational and recreational opportunities, which includes a Visitors Center, several public parks maintained by Constellation, and access to the river for fishing, bird-watching, picnics, photography, and more.

Constellation received a 50-year license from the Federal Energy Regulatory Commission (FERC) on March 19, 2021 to continue operating the Conowingo Dam. The license is a critical step forward for Chesapeake Bay restoration efforts and paves the way for long-term investments that will enhance water quality, fish and eel passage, aquatic habitats and debris removal. It also enables the continued operation of Maryland’s largest source of renewable energy, which generates safe, reliable power for tens of thousands of families and businesses in the state.

Conowingo Dam Crest Gates​

To comply with Federal Energy Regulatory Commission (FERC) requirements, we open the dam's crest gates when river conditions require. We are committed to continually informing and working with community and government partners to fulfill our shared responsibility to protect and restore the health of the bay.

Constructed in 1928, the Conowingo Dam originally produced 252 megawatts (MW) of power, becoming the second-largest hydroelectric project in the United States after Niagara Falls. Today, the dam includes 11 turbines and can generate up to 572 MW of pollution-free electricity, powering 165,000 homes, on average. In fact, the dam's renewable energy production is greater than all other Maryland renewable energy sources combined.

The dam is also a critical player in meeting the state’s renewable energy and climate action goals and prevents 867,000 metric tons of greenhouse gas emissions each year, the equivalent of taking 186,000 cars off the road.

In addition to powering homes and businesses, the Conowingo Dam produces economic and environmental benefits for both the state and local communities throughout the region.

In October 2019, the State of Maryland and Constellation reached a historic agreement that will help protect the Chesapeake Bay for decades to come. Read more about the full agreement. 

As a part of Maryland’s vital energy infrastructure, the Conowingo Dam provides $273 million in economic benefits every year, which includes supporting 265 full-time equivalent jobs, paying $10 million in annual state and local taxes, and attracting 365,000 recreational visits annually. As a major tourist site in eastern Maryland, the Conowingo Dam and recreation area contribute to Cecil and Harford Counties’ $21.7 million in tax revenue from tourism in 2018. The Conowingo Pond, located behind the dam, is vital to the water supply for several communities, serving as a back-up water supply source for both the City of Baltimore and the Chester Water Authority.

With more than a dozen community events every year, Constellation is proud to be involved with several charitable activities and non-profit organizations committed to Maryland and the Chesapeake Bay. Our employees proudly participate in a variety of charitable activities, such as donations to the local United Way chapters, the Boys and Girls Clubs of Cecil and Harford Counties, the Harford Family House, the Stroud Water Research Center, and the Plumpton Park Zoological Gardens, Inc., among others. 

We share the State of Maryland’s commitment to restoring and sustaining the health of the Chesapeake Bay. That's why in October 2019, the State of Maryland and Constellation reached a historic agreement that will help protect the Chesapeake Bay for decades to come. The benefits to Maryland and the Chesapeake Bay are valued at more than $200 million over the anticipated 50-year life of the license, which will be funded from the dam’s earnings over that time period. These funds will be used to address key issues facing the bay, including upstream debris, fish and eel passage, nutrient reduction, mussel restoration, and resiliency initiatives.

Read more about the full agreement and all of the benefits for the Chesapeake Bay. 

 

Protecting Our Waterways

One of the key environmental issues for the Chesapeake Bay is debris. Debris originates upstream from the more than 27,500 miles of tributaries and streams in the Susquehanna River watershed, flowing down through New York, Pennsylvania, and Maryland. Our agreement with the U.S. Department of Interior also includes significant investments in fish passage improvements at the dam and the creation or re-introduction of a trap-and-transport program to transport fish from Conowingo Dam to north of the York Haven Dam. In addition, Constellation will fund a total of $11 million for improvements to eel passage and to benefit nutrient reductions and aquatic habitats, plus $1 million to fund eel passage research.

To comply with Federal Energy Regulatory Commission (FERC) requirements, we open the Conowingo Dam's crest gates when river conditions require. We are committed to continually informing and working with community and government partners to fulfill our shared responsibility to protect and restore the health of the bay.

Constellation uses a variety of tools and resources to help remove the debris safely and efficiently, including:

  • Deploying crews to operate overhead cranes and grapple devices
  • Launching debris skimmer boats to assist with clean up
  • Sponsoring two major annual events: the Lower Susquehanna Heritage River Sweep and Conowingo Pond clean-up day, where we remove 600 tons of debris and refuse from the river each year
  • Supporting other groups also focused on bay clean-up efforts, as with our $25,000 donation in 2018 to the Chesapeake Bay Trust to support local debris clean-up efforts after a severe flooding event

Through these efforts, we removed more than 4,000 tons of debris in 2018 alone. Although Constellation voluntarily removes debris from the river, it is not possible to remove all debris flowing toward the dam from the upstream watershed. This is especially true during flood conditions, as seen during the summer of 2018 when the Susquehanna River swelled to 10 times its normal level.

 

Protecting Our Wildlife

The Conowingo Dam continues to play an instrumental role in wildlife conservation. In the early 1990s, a $12 million fish lift was completed at the dam, which has restored more than 1 million American shad, returning them to the upper Susquehanna River and supporting local recreational fishing. Moreover, 300 American bald eagles gather at the Conowingo Dam annually by Thanksgiving, which they use as a major breeding, nesting, and foraging ground.

  • Located on the Susquehanna River in northern Maryland, the Conowingo Dam is the largest source of renewable energy in the State of Maryland.
  • The Conowingo Dam can generate up to 572 megawatts (MW) of power. In average operating conditions, the Conowingo Dam produces enough power to supply 165,000 homes.
  • Because water is used to turn the turbines, Conowingo can be used to "jump start" the electric distribution system in the event the connection to the regional grid experiences a failure.
  • The Conowingo Pond, which is created by the dam holding back the water of the Susquehanna River, is used as a public water supply source for the City of Baltimore and Chester Water Authority (CWA).
  • Conowingo supports local residents and business throughout the region with substantial contributions to local and regional economies and the recreational opportunities it provides for thousands of residents each year.

To comply with Federal Energy Regulatory Commission (FERC) requirements, we open the dam's crest gates when river conditions require.

No, the Conowingo Dam does not produce any pollution.

  • Constellation voluntarily removes an average of 600 tons of trash and debris around the dam each year.
  • We deploy crews to operate overhead cranes and grapple devices to clear debris from the river as safely and efficiently as possible.
  • When safe, we will also launch debris skimmer boats to assist with cleanup.
  • Although Constellation voluntarily removes debris from the river, no one can remove all debris from the upstream watershed, especially during flood conditions.

Debris originates upstream from the more than 27,500 miles of tributaries and streams in the Susquehanna River watershed, which flows across New York, Pennsylvania, and Maryland.

In October 2019, the State of Maryland and Constellation reached a historic agreement that will help protect the Chesapeake Bay for decades to come.

In keeping with our strong track record of environmental stewardship, we will contribute more than $200 million from the Conowingo Dam’s operation over the next 50 years to address key issues facing the bay, including upstream debris, fish and eel passage, nutrient reduction, mussel restoration and resiliency initiatives. Specifically, the $200 million in contributions to restore and sustain the Chesapeake Bay include the following initiatives:

 

Restoration and Protection of the Chesapeake Bay

  • A contribution of Constellation lands and more than $25 million in funding to support the construction, operations, and maintenance of a mussel hatchery along the banks of the Susquehanna River. Mussels from this hatchery when stocked into the Susquehanna River basin will filter nutrients and sediment before they reach the Chesapeake Bay. This natural improvement in water quality will be further enhanced by increasing passage of an important mussel host species, American eel, at the Conowingo Dam.
  • More than $19 million of funding support for Maryland to invest in water quality improvement projects, including forest buffers and agricultural projects such as cover crops to reduce nutrient pollution.
  • More than $12 million to Maryland to support staff resources for oversight and protection of the Chesapeake Bay.
  • $5 million for chlorophyll A monitoring and reporting.
  • $500,000 to fund a feasibility study of dredge material disposal options in and around the Conowingo pond.

 

Enhanced Debris Management

 Continued commitments valued at $41 million to address debris accumulation, including an engineering study examining additional methods to divert debris before it reaches the dam, and employment of clamming, skimming, or other equally effective means of debris removal.

 

Enhanced Habitat and Fish Passage Improvements

  • $11 million of improvements to eel passage that will help facilitate mussel restoration, plus a contribution of $1 million to fund eel passage research.
  • More than $47 million in funding for climate resiliency projects, including submerged aquatic vegetation, aquaculture, clam and oyster restoration projects, and living shoreline creation to help make the Susquehanna River and Chesapeake Bay more resilient to severe weather events. 
  • Modifications to river flow valued at $52 million to enhance habitat for aquatic species like American shad and river herring, which reside downstream of the dam, and submerged aquatic vegetation, which trap sediment, remove pollution, and serve as a vital habitat for spawning and rearing fish.

 

Read more about the full terms of the agreement. 

  • Every year, the Conowingo Dam provides $273 million in economic benefits to Maryland and its local communities.
  • The dam and its employees participate in a variety of charitable activities, such as donations to the local United Way chapters, the Boys and Girls Clubs of Cecil and Harford Counties, the Harford Family House, the Stroud Water Research Center, and the Plumpton Park Zoological Gardens, Inc., among others.
  • The dam also serves as a major source of educational and recreational opportunities, which includes a Visitors Center, several public parks maintained by Constellation, and access to the river for fishing, bird-watching, picnics, photography, and more.