Scientists give Chesapeake Bay its highest environmental grade since 1992

A man looks out over the Chesapeake Bay at Sandy Point State Park in Annapolis. File Photo
A man looks out over the Chesapeake Bay at Sandy Point State Park in Annapolis. File Photo (Associated Press)

The Chesapeake Bay received a "C" on its latest report card, released Tuesday, its highest score since 1992.

In an annual survey of bay conditions, researchers at the University of Maryland Center for Environmental Science found that water clarity and the prevalence of underwater grasses increased over the past year, while levels of nitrogen pollution fell.


Ecosystems in the upper Chesapeake, north of the Bay Bridge, showed significant improvement, though conditions in the Patapsco and Back rivers in and around Baltimore remain poor, the survey found.

Scientists say the data shows that efforts to reduce the pollution flowing into the estuary are working.


"Never been so happy to be a 'C' student," said Ben Grumbles, secretary of the Maryland Department of the Environment. "We're not celebrating average. We're celebrating positive trends."

The bay has scored this high only twice since 1986, and those scores came in years of sustained drought — when there was little precipitation to wash pollutants into the bay.

Rain fell at a typical rate in 2015, and yet pollution declined.

"I think we're reaching the point where we're building resiliency back into the ecosystem," said Nicholas DiPasquale, director of the U.S. Environmental Protection Agency's Chesapeake Bay Program.


The 2015 study marked the estuary at 53 percent toward reaching a broad set of goals for ecosystem health, tying a score achieved in 2002 and behind only 1992 in studies that go back to 1986. The score represents a synthesis of about 20,000 data points that Maryland and Virginia officials collect year-round.

This was the bay's third straight year of steady improvement. It was 50 percent of the way to benchmark standards in 2014, and 45 percent in 2013.

Still, more improvement is needed for the state to meet a "pollution diet" established by the Environmental Protection Agency to dramatically reduce the volume of contaminants and sediment flowing into the bay by 2025.

The bay won't reach an "A" grade until benchmarks that include levels of nitrogen, chlorophyll, phosphorus and oxygen in the water reach 80 percent of goals.

Kim Coble, vice president of the Chesapeake Bay Foundation, called the score "good news" but said the region is not on track to meet the long-term goals.

"Bay jurisdictions, with EPA's leadership, need to do significantly more if we are to realize a restored bay by 2025," Coble said.

Weather can be a key factor in the health of the bay. Its worst scores came in 2003, when Hurricane Isabel hit, and in 2011, the year of Hurricane Irene and Tropical Storm Lee. Heavy rainfall across the Chesapeake watershed, which stretches from Virginia to upstate New York, means more pollutants and sediment make their way into the bay.

But Bill Dennison, vice president for science applications at the environmental science center, said the data shows that the impact of weather is lessening — a signal there are less pollutants spread across the land for the rain to flush away.

"This is not just a weather report," Dennison said.

Donald Boesch, president of the environmental science center, said previous years with similar rainfall patterns have posted lower scores. Researchers began releasing the report card in 2006, when the bay earned a "D-plus", but they have gathered the data going back two decades earlier.

"We feel confident in saying this is a robust trend," Boesch said.

Scientists credit factors such as sewage treatment upgrades, farmers' use of winter cover crops and reductions in the amount of nitrogen the atmosphere is depositing in waterways, Dennison said.

He also cited state policies such as the so-called "flush tax" — a $60 annual fee — that funds programs like a state cover crop initiative. Cover crops reduce the need for nitrogen fertilizers.

No region of the bay experienced worsening scores from 2014 to 2015. Some of the strongest improvements were observed in the creeks and rivers of Harford and Cecil counties, the Tangier Sound off of the lower Eastern Shore, and the James and Elizabeth rivers in Virginia.

The Patapsco and Back rivers also showed marked improvement, but they remain the lowest-scoring portion of the bay, earning a "D-minus" grade. That area includes the Baltimore harbor, which received failing grades in a report card by the Healthy Harbor Initiative released earlier this month.

The bay-wide report card's data shows the reduced nitrogen runoff is helping keep the water clear of algae while maintaining sufficient levels of oxygen. Nitrogen feeds algae blooms that can block sunlight from reaching bay grasses and deprive fish of oxygen.

But scientists found an inexplicable rise in phosphorus, which can also create algae blooms. Scientists had predicted that phosphorus levels would fall along with nitrogen levels. More research, including a study of sediments that pass through the Conowingo Dam on the Susquehanna River, is needed to understand why the data defied expectations, they said.

An index in the report shows a moderate increase in striped bass, bay anchovy and blue crab populations, but those data are not part of the report card grade because they are not collected in detail across the entire bay.

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