State officials have voiced strong concerns about updated Chesapeake Bay computer modeling that shows little overall progress in controlling nutrient runoff from farmland.

The updated modeling suggests that meeting the Bay’s 2025 cleanup goals — already highly unlikely — will be even more difficult than regional leaders believed just a few months ago.

Nutrient pollution from farmland continues to be the largest form of pollution in the Chesapeake Bay. All states in the Bay watershed face significant challenges in reaching pollution reduction goals by 2025. Credit: Dave Harp / Bay Journal Media

If correct, the figures indicate that work over the past decade by farmers to plant cover crops, install stream buffers, construct manure storage facilities and undertake other conservation practices were largely offset by increased crop production, more fertilizer use, and more livestock.

The model revisions also show greater increases in nutrient pollution from urban stormwater than previously estimated, but those were small compared to the farm changes.

The U.S. Environmental Protection Agency recently signed off on the model changes, saying the updates followed normal procedures approved by the state-federal Bay Program.

But state officials questioned the new results at recent meetings and in written comments, citing uncertainties with the underlying data. They also worry about creating the perception within the farm community, where distrust of Bay computer modeling is already high, that efforts to reduce runoff have produced few results.

The EPA uses the computer model to track progress toward meeting nutrient reduction goals under the Bay’s total maximum daily load, or “pollution diet,” established in 2010.

The TMDL set the maximum amount of nitrogen, phosphorus and sediment that can reach the Bay each year from states in the watershed. States are to implement all actions needed to achieve those goals by 2025.

The updated calculations show estimated annual nitrogen reductions from 2009 to 2020 being 6.25 million pounds less than what was calculated just a few months earlier, largely because of new data showing the intensification of farm operations, including a sharp increase in fertilizer use.

That means the region has achieved only about a third of the 71 million pounds of nitrogen reductions needed to meet the 2025 goal. And most of those reductions came from upgrading wastewater treatment plants, a job that is mostly completed. The vast majority of future nitrogen reductions must now come from farms and, to a lesser extent, urban stormwater.

The story was better for phosphorus as the figures showed 533,000 more pounds of reductions than previously estimated.

But the region was already on track to meet phosphorus goals, while significantly off track for nitrogen, which tends to have a worse impact on Bay water quality.

State officials have questioned the underlying data, and many contend that the model results sometimes show worsening nutrient trends in places where water quality monitoring shows improvements.

“We don’t think that the data sources are the right data sources … or even the best,” said Pat McDonnell, secretary of the Pennsylvania Department of Environmental Protection, at a May 17 meeting of senior state and federal environmental officials. “It just puts us, and I’m sure other jurisdictions, in a challenging position.”

Scott Mandirola, deputy secretary of environmental affairs with the West Virginia Department of Environmental Protection, said the results showed a tenfold increase in fertilizer use in urban areas in his state’s portion of the watershed, “which I don’t believe anybody accepts as being factual.”

Andrew Wheeler, a senior adviser to Virginia Gov. Glenn Youngkin, said officials in his state have “seen inconsistencies in the [nutrient] loading data” produced by the model when compared with water quality monitoring. He called for “transitioning to more monitoring, instead of modeling, [for] assessments of progress going forward.”

Ann Swanson, executive director of the Chesapeake Bay Commission, which includes representatives from state legislatures, said the updated findings should be used, but that states should be allowed to achieve the additional 6.25 million pounds of nitrogen reductions after 2025.

“Right now, it’s very clear that we will not reach the TMDL, [that] we will not make that pollution diet,” Swanson said. “We will hold our heads very, very high. And we will get as close as we can. And we remain with our foot on that pedal.”

EPA officials say all of the Bay states signed off years ago on the data sources used in the model and the procedures used to produce updated results. While concerns about some of the data have grown, states and the EPA have failed to reach agreements on alternative information sources or other fixes. EPA officials say they plan to continue to work with states to address the issues they raised.

Joe Wood, a senior scientist with the Chesapeake Bay Foundation’s Virginia office, acknowledged that there are questions about some of the data but said the new figures should be used because they followed agreed-upon protocols.

Wood questioned whether states would be voicing similar concerns if the revisions had shown them to be making greater progress, instead of less.

“If we had these anomalies, and all of a sudden everything looked a lot better than it previously did, would we have the same reaction?” Wood asked. “The process is what it is, and if you change it because it makes things look more difficult — that’s challenging to me to wrestle with.

“The fact of the matter is, we’re behind, and we’re not getting where we need to go,” he said. “Regardless of whether we change these numbers to reflect new data or not, we’re still severely behind.”

Under procedures followed by the state-federal Bay Program partnership, the model is updated every two years to incorporate new data, science, and estimates of growth in the watershed. Those updates in the past have reduced estimated progress, but not by such a large amount — and they were farther away from the 2025 deadline.

“I think the intentions are good,” said Lee Currey, director of the water and science administration at the Maryland Department of the Environment. “You want to use the best science. You want to incorporate [new] information every two years. But in the real world, that can be really challenging.

“I think what’s important is that you don’t lose sight of the good things that have happened. A model doesn’t erase those.”

Karl Blankenship

Karl Blankenship is editor-at-large of the Bay Journal.

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