Maryland Gov. Larry Hogan (R) is moving forward with his goal of reducing sediment overflow from the Conowingo Dam, announcing Tuesday that his administration will request bids to test dredging the reservoir and reusing the materials.
The plan, which would involve removing about 25,000 cubic yards of sediment from an estimated buildup of 31 million cubic yards, could help determine whether a more expansive dredging operation could improve the health of the Chesapeake Bay, he said.
Conowingo Dam, in northeast Maryland on the Susquehanna River, aids in preventing sediment from smothering aquatic grasses that provide food, habitats and oxygen for marine life in the Chesapeake Bay.
“Much of our efforts to protect the bay and safeguard our environment for future generations could be wiped out by the effects of one bad storm,” Hogan said. “This is a growing threat that must be addressed.”
Benjamin H. Grumbles, the state’s secretary of the environment, said the test project would cost the state about $4 million. The state will issue a request for proposals Aug. 31 and award a contract this fall, with the dredge operation starting before spring.
Hogan raised concerns about the dam’s sediment ponds during his 2014 gubernatorial campaign, saying that the reservoirs were long overdue for dredging and that upriver states needed to bear some of the burden for the costs.
After taking office, he proposed that the dam’s owner, Exelon, should pay most of the cost, which he said could be $250 million. The company runs an active hydroelectric generating station at the site.
Grumbles said that the state will pay for the test project but that the administration plans to discuss cost-sharing options with other states, the federal government and private partners for a potential larger-scale operation in the future.
For years, Maryland farmers have been at odds with environmentalists over whether sediment from the dam poses a major threat to the Chesapeake Bay compared with the phosphorus and nitrogen coming from agricultural lands and municipal sewer systems.
Farmers, concerned that the cost of preventing chemicals and animal manure from reaching waterways had become too costly, pushed the state to focus more on sediment overflow. But environmental groups, worried about abandoning efforts to reduce nutrient pollution, said the sediment issue was overstated.
The U.S. Environmental Protection Agency, which runs a multibillion-dollar plan to clean up the Chesapeake Bay by limiting phosphorus and nitrogen, said in a 2009 study that the reservoir behind the Conowingo Dam was about half full with sediment and could continue collecting deposits for decades to come. But the EPA and the U.S. Geological Survey have concluded more recently that the reservoir is nearly full.
Grumbles said the test project is part of a holistic approach to protecting the bay.
“The science is clear that unless this sediment is dealt with and we have pollution controls upstream, we can’t meet our Chesapeake Bay cleanup goals,” he said. “They’re both important, but nothing has been done to date on sediment behind the dam, so we view this as a positive step forward.”
In May, the University of Maryland Center for Environmental Science gave the Chesapeake Bay one of its highest grades for overall health in 30 years of scoring.
Hogan said his administration is also fighting efforts in Congress to diminish the role of states in reauthorizing hydroelectric-power projects.
Exelon is seeking to renew its federal license to operate Conowingo Dam for 46 more years, which would require the state to certify that the structure meets Clean Water Act standards. The state must issue its determination by May 16.