Legitimacy of EPA Total Maximum Daily Load rule called into question

The Agricultural Nutrient Policy Council (ANPC), a coalition of agricultural groups, released a third party report last month conducted by LimnoTech that raises significant questions about the data used by the Environmental Protection Agency (EPA) to develop and implement the Chesapeake Bay Total Maximum Daily Load (TMDL) rule. In a report, “Assessment of the Effects of Conservation Practices on Cultivated Cropland in the Chesapeake Bay Region,” developed by the U.S Department of Agriculture (USDA), very different estimates of pollutant loads to the Chesapeake Bay are reported compared to EPA’s data.

“Basically, we have two different agencies in this administration studying the same thing but yielding completely different results,” said Ashley Lyon, deputy environmental counsel for the National Cattlemen’s Beef Association. “USDA’s report clearly shows that farmers and ranchers have already significantly surpassed EPA targets for reductions in sediment and phosphorus.”

The LimnoTech report found many discrepancies between USDA’s report and EPA’s data. The LimnoTech study found that USDA and EPA make different assumptions about animal feeding operations (AFOs) and confined animal feeding operations (CAFOs). EPA attempts to model loads from the CAFO production areas, where animals are housed and manure stored, while USDA does not. Both EPA and USDA appear to model manure application on cropland on a nitrogen basis. USDA estimates that 38% of cropped acres have manure applied. According to the LimnoTech study, it is not possible to determine from the available EPA documentation how much of the cropland receives manure.

The report calls for a “timeout” on the Bay TMDL to make sure that EPA does not push the use of its pollutant estimation model beyond its original design. It asks EPA to not issue a rule setting the Bay’s “pollution loads” until the inconsistencies between the USDA and EPA reports can be reconciled.

According to the third-party report, “USDA estimates that 7% of cropped acres are under conventional tillage, 5% of cropped acres have a level of tillage between conservation tillage and conventional tillage, and 88% of cropped acres are under conservation tillage (mulch till or no-till) practices …EPA estimates that 50% of cropped acres are under conventional tillage and 50% are under conservation practices. In general, the cultivated cropland conservation practices incorporated in USDA’s model framework are documented and statistically valid in sufficient detail to allow a general understanding of practices accounted for in the modeling, the assumptions made regarding specific conservation practices, and the level of implementation. A similar level of detail and documentation is not, however, available for the EPA model framework.”

“Given the seriousness of this issue and potential regulatory consequences to agriculture, it is absolutely imperative that a more accurate study is conducted. The regulations that will likely be derived from EPA’s flawed model will put farmers and ranchers out of business,” Lyon said. “This regulation not only impacts agricultural producers living on the Chesapeake Bay watershed but lays the foundation for all watersheds. Sound science must be the basis for any regulations.”

According to the LimnoTech study, the USDA model framework seems to more accurately represent Chesapeake Bay watershed agricultural operations and management practices, including consideration of crop rotations, varying levels of tillage (no-till, mulch till, conventional till) and actual nutrient management practices.

“If USDA’s numbers are correct, agriculture has already significantly surpassed EPA targets for reductions in sediment and phosphorus,” said National Association of Corn Growers Director of Public Policy Rod Snyder. “It is crucial that farmers in the Bay watershed receive appropriate credit for their efforts to be good stewards of our land and water resources.”

The LimnoTech report is available at nutrientpolicy.org/ANPC_News.html.

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