Over the last four decades, leaders across all levels of government have worked in concert to restore the health of the Chesapeake Bay. A report card issued by the University of Maryland Center for Environmental Science (UMCES) two weeks ago shows that the efforts are working—mostly.

The report card received an overall score of C+, the highest in the 40 years since its health has been measured in this way by UMCES.

“This is definitely a high-water mark, and it's an indication that the investments we've been making in wastewater and stormwater and our agricultural sector are starting to pay dividends,” said Jay Ford, Virginia policy manager at the Chesapeake Bay Foundation.

But issue areas remain, including in the York and Elizabeth rivers in Virginia, the Patapsco and Back rivers in Maryland and the Lower Susquehanna watershed in Pennsylvania, which all received D or D+ scores.

“Rivers like the Patapsco, Patuxent, and Choptank continue to be overburdened by pollution, which is driven by increased…