May 23, 2019 — A year of historically heavy rainfall strained the Chesapeake Bay’s ecosystem — but not past the breaking point, according to a wide-ranging assessment released Tuesday.
The estuary’s overall health score in 2018 dropped from 54% to 46% but retained its “C” grade for a seventh consecutive year, according to the University of Maryland Center for Environmental Science’s latest report card.
It marked the lowest grade since 2013 and reversed a streak of four years of improving or steady scores.
“We don’t have as good of news to report because of some record rainfall,” said Bill Dennison, UMCES vice president for science application. “The good news is it took a hit, but it did not crash.”
The federal government and the states within the 64,000-square-mile Bay watershed are working on a plan to reduce nutrient and sediment pollution under an agreement signed in 2010. The effort faces a 2025 deadline.
The resilience of that recovery faced one of its biggest tests last year. About 72 inches of rain inundated the Baltimore area during 2018, about 30 inches more than normal, according to the report.
From a scientific perspective, the deluge offered a glimpse of how the recovering ecosystem may respond as climate change leads to increasingly erratic weather, Dennison said.
Many scientists predicted that last year’s rains would dampen the restoration gains. The UMCES report bears out those projections, showing reductions in the scores for water clarity, nitrogen, phosphorus and aquatic grasses.