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Editorial Manure Manger: November-December 2013

A wealth of recent data about Chesapeake Bay and the Delmarva Peninsula is giving agriculture and the nutrient management industry a lot to think about in terms of total maximum daily load (TMDL) targets – and it’s important to be educated about this key issue.

The American Farm Bureau Federation (AFBF) announced this past fall that it is appealing a district court decision upholding the U.S. Environmental Protection Agency’s TMDL limits imposed on nutrients entering the Chesapeake Bay area.

The AFBF had originally challenged the limits, set in 2010, on the amount of nitrogen, phosphorus and sediment that can enter the watershed, due to concerns the EPA had been granted a wide frame of reference regarding local land use and development.

“This is a wrongly decided case that has dangerous implications for farmers and many others in the Chesapeake Bay area and nationwide,” said AFBF president Bob Stallman. “This case isn’t about whether or not to protect the Chesapeake Bay – we all share that goal. This case is about whether EPA can dictate where farming will be allowed, where homes can be built, and where businesses can be established. By taking over decisions like that, EPA has turned the whole concept of cooperative federalism out the barn door.

Meanwhile, the American Water Resources Association Journal themed its October 2013 issue around Chesapeake Bay Total Maximum Daily Load (TMDL) Development and Application. According to publication officials, 10 papers plus an introduction were published in the journal, telling the story of the Chesapeake Bay TMDL from developing water quality standards through to establishing allocations – an issue they described as results of a recently published “an up-to-date picture of the result of 30 years of restoration effort.”

That restoration effort might take a bit longer than expected, given the results of a recently published U.S. Geological Survey (USGS) study on the Delmarva Peninsula. According to that research, it may take several decades for current water-quality management practices to achieve their goal due to lag response time, which is the time between implementing management actions and the resulting improvements.

The study, conducted by Ward Sanford, shows that the ages of groundwater in Chesapeake Bay and Delmarva can range from less than a year to centuries, with the median age being between 20 and 40 years. These results indicate that groundwater age in the area is much older than was originally estimated. That estimation was based on the age of groundwater located west and north of Chesapeake Bay, which has a median age of 10 years.

“The USGS research found that in some areas of the Delmarva, the groundwater currently discharging to streams is gradually transitioning to waters containing higher amounts of nitrate due to fertilizer used during the 1970s through the 1990s,” the report states. “Similarly, the total amount of nitrogen in the groundwater is continuing to rise as a result of the slow groundwater response times.”

According to Sanford’s model, a 12 percent increase in nitrogen loads from the Delmarva to Chesapeake Bay is expected by 2050 if additional management practices are not put into place.

All of this information provides much to consider and raises many questions: What happens if the EPA TMDL models are flawed? Is the region shooting for targets that are unattainable? And, given the new information on lag response time, will anyone be able to meet the targets in the required time?

Hopefully, the answers will emerge as this important appeal goes forward.