The Chesapeake Bay’s health dipped in 2024, due in part to extreme weather conditions causing stormwater runoff to carry pollutants into the waterway, a University of Maryland report finds.
The Chesapeake Bay earned an overall score of a C grade (50%), which is 5 points lower than last year’s overall score of C+ (55%), according to the University of Maryland Center for Environmental Science’s 2025 Chesapeake Bay and Watershed Report Card released on Tuesday.
But the Bay’s health has still shown improvement compared to levels in the 1980s, the report finds.
“The health of the Chesapeake Bay isn’t just an environmental issue. It’s a quality-of-life issue for nearly 19 million people,’ said Hilary Harp Falk, president and CEO of the Chesapeake Bay Foundation, a partner of the UMCES. “This report card reflects the progress we’ve made, and the serious challenges that remain. This is the moment to push forward—not pull back.”
The report attributes last year’s health decline, in part, to climate change intensifying extreme weather conditions in 2024. Last year saw periods of drought that dried out soil, followed by heavy storms washing pollution into streams, rivers, and the Chesapeake Bay.
“Last year was the hottest year on record and there were extreme rainfall patterns,” the report reads. “While parts of the watershed experienced drought, brief but intense downpours also caused runoff into Bay waters. These downpours can cause water to flow over the ground rather than soak into it, increasing the fertilizer, dirt, and debris carried into waterways.”
Such extreme weather conditions could become more frequent as the Trump administration continues to roll back policies and slash programs aimed at curbing climate change, including the Environmental Protection Agency, the National Oceanic and Atmospheric Administration, the U.S. Department of Agriculture, and the U.S. Geological Survey.
“The extreme weather of 2024 is not an anomaly—it’s a warning,” Falk said. “Climate change is accelerating, and with it comes more flooding, pollution, and ecological stress. The Trump administration’s proposed budget cuts threaten the world-class science and partnership at the heart of the effort.”
The report highlighted moderate and poor conditions for most regions of the Chesapeake Bay. Six regions demonstrated slight (Lower Bay) or significant improvement (Upper Bay, Upper Western Shore, Patapsco & Back Rivers, James River, and Elizabeth River).
Meanwhile, eight regions showed no change (Lower Western Shore, Choptank River, Patuxent River, Mid Bay, Potomac River, Lower Eastern Shore, Rappahannock River, and York River). Only one region (Upper Eastern Shore) showed slight decline in health.
For the Bay overall, measurements of dissolved oxygen, aquatic grasses, total phosphorous, and total nitrogen trended positively.
Measurements of the benthic community – bottom-dwelling organisms such as oysters, mussels, and other life – demonstrated a neutral trend, while negative trends were recorded for Chlorophyll A and water clarity.
“Improving trends can be attributed to management and restoration efforts at the regional, state, and local levels,” the report reads. “Regionally, wastewater treatment plants have been upgraded, and programs have been put in place to reduce nutrient and sediment input. State efforts include seagrass restoration, oyster plantings, and watershed planning. Communities play a huge role in improving Bay health by managing their local resources.”
The report also gave the Chesapeake Bay Watershed an overall score of C+ (57%), with the score based on indicators in three categories:
- Ecology (comprising income equality, affordable housing, household income, and jobs growth)
- Society (comprising walkability, heat vulnerability, and social index)
- Ecology (comprising temperature stress, water quality, benthic community, fish community, and protected lands)
The watershed was strongest in the jobs growth (87% or A) and temperature stress (84% or A-) indicators, with good scores as well for household income, water quality, and protected lands.
The lowest score (25% or D) was for income equality.
“This means that although there are more jobs across the watershed, there are still strong disparities in the amount of income people are earning,” the report reads.
Earning moderate scores were indicators for affordable housing, walkability, heat vulnerability, social index, benthic community, and fish community.
