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Report: Extreme Rainfall Hurt Chesapeake Bay Health

Another day, another report card on the health of the Chesapeake Bay.

The latest, released Tuesday, is from the University of Maryland Center of Environmental Science, graded the Bay’s overall health as a C. The report found that heavy rainfall in 2018 negatively impacted the score – even though the Bay’s long-term health trend is improving.

“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. This is encouraging because the Bay is showing resilience to climate change,” said Bill Dennison, vice president for Science Application at the University of Maryland Center for Environmental Science.

Almost all indicators of Bay health, such as water clarity, underwater grasses, and dissolved oxygen, as well as almost all regions, declined in 2018. In particular, chlorophyll a and total nitrogen scores had strong declines due to very high rainfall, which caused nutrient runoff that then fed algal blooms.

Of the many factors that affect Chesapeake Bay health, the extreme precipitation seen in 2018 appears to have had the biggest impact. The Baltimore area received 72 inches of rain in 2018, which is 170 percent above the normal of 42 inches. As a result, the reporting region closest to Baltimore—the Patapsco and Back Rivers—saw a decline in health, decreasing to an F grade in 2018. The strongest regional declines were in the Elizabeth River and the Choptank River. The two regions that remained steady were the Lower Bay and the York River.

However, the overall Bay-wide trend is improving. Since 2014, all regions have been improving or remaining steady.

“This report, along with the great news that Maryland’s crab population has grown 60 percent, is yet another promising sign of ongoing improvement of the Bay and that our continued investment is making a difference,” Gov. Lawrence J. Hogan Jr. (R) said in a statement.

Beth McGee, Chesapeake Bay Foundation director of Science and Agricultural Policy, said the latest study suggests that more needs to be done to curb pollution in and near the Bay.

“The Bay is recovering but it is a fragile recovery,” she said. “Extreme weather caused by climate change means pollution must be reduced even more from sources we can control. The states and federal government must do more to save the Bay.”

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Report: Extreme Rainfall Hurt Chesapeake Bay Health