The health of the Chesapeake Bay is improving significantly over time, though several benchmarks continue to lag behind, according to an annual report card released Tuesday.
The bay overall earned a 56%, which translates to a C-plus on the 20-point scale officials use for scoring. That’s an increase of 6% from last year and the best grade in four decades of data tracking.
“We recognize we have a long way to go,” said David Bulova, Virginia’s Secretary of Natural and Historic Resources, at an event Tuesday celebrating the release of the report. “We are taking this as an opportunity to acknowledge that what we are doing is working, and that we have momentum moving forward.”
The University of Maryland Center for Environmental Science creates the score based on data from the previous year, meaning this grade reflects conditions in 2025.
Factors include water clarity, underwater plants, marine organisms, oxygen in the water and nutrient pollution.
Program manager Alexandra Fries said the report card started in 2006 “as a way to synthesize information in order to make better decisions about the Chesapeake Bay.”
It’s gotten more detailed, such as adding indicators and expanding to look at not only the boundaries of the bay but also tributaries throughout the 64,000-square-mile watershed, she said.
For a long time, the numbers didn’t budge much.
“It seemed like we were just holding the line.”
The new score finally captures long-term trends, she said. The greatest gains were in dissolved oxygen and reducing pollution from nitrogen and phosphorus.
Yearly data varies depending on weather conditions, such as heavy rains that wash pollution into the bay. Last year was relatively dry.
“But seeing the significantly improving trends over time shows us that it's not just the weather patterns that are affecting it,” Fries said. “It's also our actions. And despite increasing development pressure, a bigger population, we're still improving.”
Bulova said Virginia’s population has grown by more than 3 million people since the original Chesapeake Bay Agreement was signed in 1983, and is expected to grow by another million by 2040, which is the agreement’s next deadline.
“I think what makes that progress all that more spectacular is the headwinds that we face with population growth, in the face of climate change, in the face of invasive species like blue catfish,” he said. “When you think about it, I'm amazed that we make progress at all.”
Oysters are a big highlight of the new report. Last year, the Chesapeake Bay Program announced it would achieve a goal set more than a decade prior for restoring native oyster reefs.
Since 2014, 11 bay tributaries in Maryland and Virginia have restored and protected about 2,400 acres of reef habitat, including planting more than 7.5 billion oysters.
The lower part of the bay, in southeastern Virginia, appears to be doing the best. The region received a B-plus, the highest on record.
However, there are trouble spots, such as the York and Elizabeth Rivers.
In the bay overall, two indicators have continued to worsen: water clarity, which reflects the murkiness of the water and how far light can penetrate through; and chlorophyll a, which is a measure of algae in the water.
Scientists don’t know exactly why these aspects are declining, Fries said. Sediment pollution, from sources such as construction projects, could be hampering water clarity.
Authors also noted that a massive sewage spill in January in Montgomery County, Maryland could affect next year’s outcome. Water monitoring earlier this year found bacteria levels in the area were hundreds of times higher than normal after the spill of up to 400 million gallons of raw sewage.
The report card comes weeks after President Donald Trump repealed an Obama-era executive order that had helped coordinate the long-running effort to clean up the Chesapeake Bay.
Fries said the evidence of progress reiterates that the federal model has been working.
“For many years we were like, ‘We're putting all this time and money and effort, and we're not seeing an improvement for years and years and years,’ and so that can get very tiring and easy to say, ‘why are we bothering to do this?’’ she said.
“But if we hadn't been doing those things, maybe we would be declining. Maybe we'd be losing the resources that we rely on for tourism and recreation and local economies. Water quality connects everything in the bay.”
