By Brian Witte

The health of the Chesapeake Bay improved to a grade of C in 2020 — up from a C-minus in 2019, according to an annual report card by scientists released Tuesday.

Individual indicators on the health of the nation’s largest estuary had mixed results in 2020, but the report released by the University of Maryland Center for Environmental Science found the overall bay-wide trend continues to improve over time.

For the first time, the report card examined new indicators of watershed health, including stewardship, protected lands, walkability, and heat vulnerability. Scientists have been putting a focus on assessing not just the environment, but also the social and economic factors that influence ecosystem health.

“This year’s report card provides new insights in our journey of restoring the Chesapeake Bay,” said Dr. Peter Goodwin, the president of UMCES. “Improvements in our environment go hand-in-hand with improvements in our communities.”

Seven out of 15 regions showed significantly improving health trends, the report said.

Dissolved oxygen and total nitrogen scores improved, while chlorophyll and total phosphorus scores declined. Water clarity, benthic community — organisms in the bottom of the bay — and aquatic grass scores decreased slightly.

Because of the pandemic, UMCES said there was a monitoring gap from March to May. The effects of the COVID-19 pandemic on the ecosystem health of the bay are not yet known, besides a reduction in atmospheric nitrogen, which has a declining trend, continued by reduced travel during 2020.

The overall grade for the Chesapeake watershed was a B-minus for 2020. That’s the same as it was in 2019, which was the first year UMCES included a separate grade for the overall watershed, which includes the six states of Maryland, Virginia, Delaware, Pennsylvania, West Virginia, New York, as well as the District of Columbia.

The report card has been released in each of the last 15 years. The analysis of the watershed’s health uses 23 reporting regions. It incorporates both ecological and social indicators in its scores. Four new watershed health indicators were assessed this year including: stewardship index, protected lands, heat vulnerability index and walkability.

The stewardship index looks at actions residents are taking to support the bay, volunteerism, and civic engagement. The report said there was room to grow in this area, which scored a D-plus grade.

The protected lands indicator measures the valuable lands protected in the watershed that maintain water quality and habitat, sustain forests, farms, and communities and support community values.

The heat vulnerability index focuses on climate safe neighborhoods throughout the watershed and includes data on tree canopy, impervious surface, temperature and poverty.

Walkability describes how many people can walk to a park in 10 minutes, which was particularly important in a pandemic year.

UMCES incorporated socioeconomic indicators in the 2019 report card for the first time in addition to ecological indicators.

UMCES says it is expanding on those indicators by having graduate students at the state’s university system develop an environmental justice index. More indicators will be added next year, particularly ones that address economic disparities.