Long considered a laggard in Chesapeake Bay cleanup efforts, Pennsylvania last year led the watershed in nitrogen reductions reported by the state-federal Bay Program partnership.
The state was recognized for making nearly 4.5 million pounds of nitrogen reductions in 2020, accounting for nearly half of the 10 million pounds attributed to the entire watershed, according to Bay Program computer models.

Still, the recently released figures show that the region as a whole remains far behind the pace needed to meet its 2025 pollution reduction goals for nitrogen, a key nutrient affecting Bay water quality.
From 2009 to 2020, watershed states reduced the amount of nitrogen reaching the Bay by just 29%, leaving more than 70% of the work to be accomplished in just five years.
Much of the shortfall is in Pennsylvania, largely because the great majority of its nutrient runoff comes from the 33,000 farms in its portion of the Bay drainage. All states have struggled to control farm runoff, according to the models.
The nitrogen reduction credited to Pennsylvania for 2020 was more than the state had accomplished in the entire previous decade, according to model estimates. But they show that the state would have to control another 32.5 million pounds to meet its 2025 goal.
The 2020 progress did not represent a dramatic ramp-up in an effort, though. About 75% of the credited reductions resulted from improved reporting of nutrient discharges from wastewater plants that had previously been upgraded. Similarly, much of the reduced agricultural runoff stemmed from better accounting for actions previously taken by farmers.
Patrick McDonnell, secretary of the Pennsylvania Department of Environmental Protection, praised wastewater treatment plants and conservation districts for helping to improve tracking and applauded the work of farmers for achieving a “record reduction.”
Russell Redding, Pennsylvania’s agricultural secretary, also credited farmers for their actions, particularly for the more efficient use of fertilizers. “Increasingly, farmers recognize that soil, nitrogen, and phosphorus running off the land into streams is a symptom of a farm operating at less than peak efficiency,” he said.
Frustrated by the state’s slow progress, the states of Maryland, Delaware, and Virginia, along with the District of Columbia and the Chesapeake Bay Foundation, have sued the U.S. Environmental Protection Agency, saying it has not done enough to force Pennsylvania to do more to meet Bay cleanup obligations.
Harry Campbell, director of science policy and advocacy in the Bay Foundation’s Pennsylvania office, said it was encouraging that improved information showed the state’s efforts are having results. And, he said, initiatives to secure financial support, both at the state and federal level, could produce greater progress.
“I think it is critically important for that positive momentum to show that Pennsylvania — not easy by any stretch of the imagination — can do this,” Campbell said. “And that if we have sufficient investment … we could have a significant uptick in implementation.”
After Pennsylvania, most of the 2020 improvements were credited to Maryland, which reduced nitrogen by 4.1 million pounds. Much of that, almost 3 million pounds, came from upgrades and improved performance at wastewater treatment plants, said Jay Apperson, spokesman for the Maryland Department of the Environment.
Most of the rest of the state’s reductions came from agriculture, though runoff from developed lands also dropped — Maryland and the District of Columbia were the only jurisdictions to show decreases in urban runoff.
Overall, the region is attempting to reduce the amount of nitrogen that annually reaches the Bay from its watershed from 270.8 million pounds in 2009 to 199.3 million pounds by 2025.
The Bay Program estimates annual progress toward that goal based on the amount of runoff control practices states report installing each year, such as nutrient-absorbing cover crops or stream restorations, as well as wastewater treatment plant upgrades.
That information is fed to a computer model that estimates the impact those actions would have in reducing the amount of pollution reaching the Bay in a year with “average” rainfall. But years with more precipitation send more nutrients to the Chesapeake, while drier years result in less runoff.
Many on-the-ground actions, such as cover crops or streamside forest plantings, can take years to produce results that reach the Chesapeake, so the full impact of actions taken now may not be realized for decades. The regional goal is to have enough practices in place by 2025 to fully meet Bay water quality goals at some point in the future.
Based on the most recent model estimates, steps taken through 2020 would eventually reduce the amount of nitrogen reaching the Bay to 241.5 million pounds a year. That’s far off track from what’s needed by 2025.
The challenge is especially difficult because more than 80% of the remaining nitrogen reductions need to come from agriculture, a sector in which all the states have struggled to make progress. No state has shown a sustained rate of progress that would meet Bay nitrogen goals.
The story is better for phosphorus, another targeted nutrient, where progress is generally on track. But nitrogen is the nutrient primarily responsible for fouling the Bay and fueling the growth of algae blooms that cloud its water and deplete it of oxygen, creating “dead zones” as the excess algae decompose.
Overall, the Bay Program’s figures for 2020 show the following:
- New York reduced its nitrogen loads from 13.87 million pounds in 2019 to 13.24 million pounds in 2020. Its goal is 11.8 million pounds.
- Pennsylvania reduced its nitrogen loads from 110.4 million pounds to 105.99 million pounds. Its goal is 73.49 million pounds.
- Maryland reduced its nitrogen loads from 52.02 million pounds to 47.96 million pounds. Its goal is 45.83 million pounds.
- Virginia reduced its nitrogen loads from 58.35 million pounds to 58 million pounds. Its goal is 52.95 million.
- West Virginia reduced its nitrogen loads from 8.07 million pounds to 7.96 million pounds, surpassing its goal of 8.23 million pounds.
- Delaware’s nitrogen loads increased from 6.7 million pounds to 6.9 million pounds. Its goal is 4.55 million pounds. (The state reported problems with its nutrient reduction tracking database).
- The District of Columbia reduced its nitrogen loads from 2.06 million pounds to 1.42 million pounds, surpassing its goal of 2.42 million pounds.