The Chesapeake Bay’s recovery took a step back in 2018, but the estuary retained its “C” grade on an annual report card from the University of Maryland Center for Environmental Science.
With nearly twice as much rainfall as normal across the state last year, the bay saw increases in nitrogen and phosphorus levels and declines in abundance of underwater grasses and many types of aquatic life. The surges of precipitation throughout the year washed large amounts of pollution and nutrients into the bay from across its 64,000-square mile watershed, fouling waters and disrupting its ecology.
The Chesapeake’s overall report card score declined for the first time since 2013, falling from 54% to 46%. A score of 80% or better would earn an A grade.
UMCES scientists said the setback could be a sign of more challenges ahead for the Chesapeake.
“Climate change causes increased variability in rainfall with extreme wet and dry conditions in different regions,” they wrote. “These extremes will continue to put pressure on the entire Chesapeake Bay watershed.”
Nevertheless, they noted, “the long-term trajectory of bay health is still positive, even with the impacts of precipitation on the Bay in 2018.”
“While 2018 was a difficult year for Chesapeake health due to high rainfall, we are seeing trends that the Bay is still significantly improving over time,” said Bill Dennison, UMCES vice president for science application, in a statement. “This is encouraging because the Bay is showing resilience to climate change.”
The scientists found the worst scores for nitrogen levels in rural areas along the Mason-Dixon Line and throughout the Eastern Shore. Most of Maryland showed acceptable scores for phosphorus, while poorer scores were reported along the Susquehanna River in Pennsylvania.
The report card also noted declines in the populations of striped bass, bay anchovies and blue crabs in 2018 (though crab abundance has since rebounded in 2019). Poor levels of macroinvertebrate benthic life — bugs and other tiny crawling, swimming or burrowing creatures — were reported on creek and river bottoms across Maryland and northern Virginia.
A similar report card issued by the Chesapeake Bay Foundation in January found a similar decline in bay health amid an “assault” from excessive precipitation. The foundation dropped its grade for the bay to a D+ from a C-.
There was more than 72 inches of precipitation in 2018 at Baltimore/Washington International Thurgood Marshall Airport, about 175 percent of a normal year there.
Climate change research suggests more wet years could be ahead for the Chesapeake region, stressing a need to “remain vigilant” with bay restoration efforts, UMCES President Peter Goodwin said.