The Conowingo Dam, shown in July 2017 (Bill O'Leary/The Washington Post)

Maryland Gov. Larry Hogan on Tuesday escalated pressure on neighboring states to reduce the amount of trash and pollution flowing into the Chesapeake Bay, accusing other jurisdictions of not doing their fair share to clean up the nation’s largest estuary.

He pressed Pennsylvania in particular to help clear the blanket of debris unleashed into the Chesapeake after last month’s historic rain. The cresting floodwaters forced the Conowingo Dam’s operator to open as many as 20 of more than 50 floodgates designed to relieve pressure and lower the water level behind the dam. Since then, tree trunks, trash, tires and other flotsam have poured down the Susquehanna River through the floodgates and into the bay.

The detritus has clogged navigation channels, closed beaches and cluttered shorelines, giving Hogan (R) ammunition to lean on other states in the watershed to accelerate broader cleanup efforts.

“When it comes to the Chesapeake Bay, Maryland honestly has more to lose than any other state,” Hogan said Tuesday at an annual meeting of the Chesapeake Executive Council, which reelected him chairman. “We cannot and we should not have to address this issue alone.”

The executive council includes governors of Virginia, New York, Pennsylvania, Delaware, and West Virginia, and D.C. Mayor Muriel E. Bowser (D). It coordinates the 15-year, $19 billion Chesapeake Bay Program cleanup effort ordered by the Obama administration and overseen by the Environmental Protection Agency.

Leaders from other states pushed back against Hogan’s assertion that they should help clear the bay of debris.


Maryland Gov. Larry Hogan, left, and Democratic gubernatorial nominee Ben Jealous. (Pete Marovich for The Post and AP/Pete Marovich for The Post and AP)

New York’s representative at the meeting, Deputy Commissioner James Tierney of the New York State Department of Environmental Conservation, said water leaving the state’s borders is cleaner than when it reaches the bay.

Pennsylvania’s environmental secretary, Patrick McDonnell, declined to commit resources to cleaning up the debris, saying his government has been dealing with historic flooding that killed two people in the state.

“We were, frankly, in flood response mode,” McDonnell said.

Maryland officials have no estimate on how much new debris is in the bay, but the Department of Natural Resources said crews pulled out 5,000 pounds Sunday.

Hogan’s administration has asked Exelon, the operator of the hydroelectric Conowingo Dam, to help with cleanup efforts. In a Monday letter to the company, administration officials said the state “simply does not have the resources to clean up all the pollution that flowed through the bay last week.”

Exelon officials said in a statement that they have already voluntarily cleared 600 tons of debris from around the dam this year and that all of the current debris came directly from the storms. The company offered the state staff time and $25,000 to help with the cleanup, a figure Hogan derided as a “drop in the bucket.”

Will Baker, president of the Chesapeake Bay Foundation, described the volume of clutter in the bay as “historic” and a symbol of how much of the bay’s health depends on what flows off land in Pennsylvania.

“We’re more concerned with what happens 365 days a year,” Baker said. “The debris is just a stark visual reminder of the connection between Pennsylvania and Maryland.”

In late July, the EPA released its midpoint assessment of the overall cleanup effort, halfway between when the program began in 2009 and when it is supposed to be completed in 2025. The EPA noted that most states involved in the cleanup have hit their targets for reducing sediment, which scours bay grasses, and phosphorus, which fuels algae blooms that ultimately deplete the bay of oxygen.

But the states have fallen behind on efforts to reduce nitrogen, another pollutant that reduces oxygen levels in the bay.

The federal government in June singled out Pennsylvania as “significantly off track” in meeting its goals.

“We’re clearly behind,” McDonnell said during the meeting, which was held at a maritime museum in Baltimore. “We’ve taken that as an opportunity to ­double down.”

Overall, the federal cleanup efforts appear to be working. A report released in June found that the bay’s water quality was the healthiest it had been in 33 years.

Last week, Hogan used more forceful language about the debris situation, calling it “an economic and ecological crisis.”

His public pressure on nearby states comes as he is seeking a second term and touting his environmental record. Hours before the meeting Tuesday, the governor released a digital campaign ad that features footage of him telling reporters last week that other states are “not doing enough” to clean up the bay.

Hogan’s Democratic opponent, former NAACP chief Ben Jealous, said the governor’s recent efforts obscure his past actions on the environment, which include vetoing a bill to boost how much electricity comes from renewable sources.