The Chesapeake Bay Program has released new numbers showing how the Bay watershed states have performed in their efforts to reduce key pollutants entering the Bay.
The report reveals that the six Bay states (Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia), along with Washington D.C., continued to make progress between 2023 and 2024 in reducing the amount of nitrogen, phosphorus and sediment flowing into the Chesapeake. And we’re getting an overall snapshot of how much the pollution levels have improved since efforts began in 2009.
The Chesapeake Bay Total Maximum Daily Load, a pollution diet set by the U.S. Environmental Protection Agency, put limits on the key pollution offenders of nitrogen, phosphorus and sediment in 2010. Its goal was to reduce those pollutants enough to allow the Bay and its tidal rivers to reach water quality standards. The cleanup plan, known as the Chesapeake Bay Watershed Agreement, had a deadline of 2025.
Now that 2025 is here, the Chesapeake Bay Program shares how much progress has been made since the pollution diet’s baseline year of 2009. Overall, the three main pollutants have all decreased, but not enough to reach all three of the water quality goals. Phosphorous entering the Bay decreased 21.8% from 2009 to 2025, meeting 92% of the Bay states’ reduction goal. Sediment going into the Bay decreased 7.6%, reaching 100% of the reduction goal. Nitrogen entering the Bay decreased by 15.3%, meeting just 59% of its goal for 2025.
To come up with the pollutant reduction estimates, the Chesapeake Bay Program used modeling tools to analyze the practices the Bay states have put into place to prevent pollution from entering waterways. The Bay Program also factored in data on land use, fertilizer and manure use, wastewater and septic discharges, and river flow.
Each Bay state or district had a goal of putting 100% of practices in place by 2025. However, by fall 2022, it was acknowledged that the 2025 Watershed Implementation Plan Outcome will not be met on time. Indicators continue to support that the states will fall short of their goals.
Individual states’ achievements vary. Delaware, New York and Pennsylvania have not met statewide targets for sediment. Nitrogen and phosphorus modeled load reductions are off course for the Chesapeake Bay watershed as a whole; however the District of Columbia and West Virginia have met their statewide nitrogen and phosphorus targets. Maryland has met its statewide phosphorus target and is on course to meet its nitrogen target by 2025.
So how has the Bay as a whole managed to achieve the reductions it has? According to the Bay Program, the agricultural sector was responsible for 76% of the nitrogen reductions from 2023-2024. The natural sector (defined as trees, shoreline, forests and wetlands) was responsible for 46% of the phosphorous reductions and 77% of the sediment reductions during that time period.
Why are nitrogen, phosphorous and sediment such bad words on the Chesapeake Bay? These nutrients, in excessive amounts, contribute to the Bay’s poor water quality. Nitrogen and phosphorous can fuel the growth of algae blooms, which lead to “dead zone” areas of little to no oxygen. And sediment can block sunlight from reaching underwater grasses.
When a direct pollution source like a wastewater treatment plant takes action to reduce pollution, the positive changes can be immediate. But when a less-direct pollution source, like a farm or development, takes steps to reduce runoff containing fertilizer or chemicals, there can be a lag time on water quality improvements. The Bay Program continually revises its numbers as new information comes in.
Despite missing the 2025 deadline, the Bay watershed jurisdictions are still required to meet their goals. You can check the progress that each state or district is making toward its goal by visiting the 2025 Watershed Implementation Plan Outcome page. Final progress will be assessed in 2026.
With the 2025 deadline passing, the Chesapeake Bay Program is now focused on revising the new Chesapeake Bay Watershed Agreement. “We’re committed to building on this momentum for lasting improvements and a healthier Bay,” says Maryland Department of the Environment’s Gregorio Sandi, who serves as vice-chair of the Chesapeake Bay Program Water Quality Goal Implementation Team.
The Chesapeake Bay Foundation points out that the need for water quality improvements is evident in struggling populations of blue crabs and striped bass, as Chesapeake Bay Magazine has recently reported.
“The Chesapeake Bay cleanup has made tremendous progress thanks to decades of partnership at the state, federal, and local levels. But far too much pollution still enters the Chesapeake Bay,” points out Chesapeake Bay Foundation Senior Vice President for Programs Alison Prost. She calls on federal funding and state-federal partnerships to make the Chesapeake Bay healthy.
