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Eye on the Bay: W&M geologists look at riparian buffers

The Chesapeake always is on the minds of members of the William & Mary geology team investigating effectiveness of riparian buffers. Their research, which is funded by the Virginia Environmental Endowment, is part of the overall effort to save the Bay.

Riparian buffers are thin bands of forest used to prevent agricultural runoff from entering streams and rivers that form a watershed. In Virginia, such buffers are mandated at a minimum of 100 feet. Throughout the summer and into the fall, team members, led by geology professors Jim Kaste and Greg Hancock, have been collecting field samples and beginning the analytic processes to determine whether that distance is enough.

Nitrogen, phosphorous and other sediments can bypass riparian buffers and enter the Bay's watershed either as overland flow or as subsurface flow, according to Kaste. Invoking leading-edge scientific techniques, the team is measuring overland flow through the radioactive cesium that was deposited on the land during 1950s and 1960s when atmospheric testing of nuclear weapons occurred. "That cesium can be thought of as a blanket evenly spread across the land's surface," Kaste said. "As you have sediment movement post 1967, or so, the sediment takes the cesium with it.

"That testing is going to take a few months; essentially you put the sample on a detector and wait for the gamma emission from that cesium to interact with the detector," Kaste continued.

Assisting Kaste and Hancock are Morgan Stumb ('10) and Eric Newman ('10), geology majors who are working on the team as part of their senior honors projects. Stumb is focusing on use of cesium as a tracer element in determining sediment movement from the farm fields through the forest. Newman is looking at the groundwater flow.

The group's initial research is occurring on four different farms on Virginia's Middle Peninsula. In addition, it is conducting analyses on two control sites not affected by agricultural uses.

Hancock views the project as a means of bringing scientific methods to bear upon the critical question of how pollutants continue to enter the Bay. "One of the things I am interested in is bringing a geologic way of thinking about the earth to problems that are typically engineering in nature," he said. "We are interested in data-collection and observation in the field, whereas much engineering is done on paper."

Hancock explained that the relative smallness of William & Mary and the resulting interdisciplinary discussions fostered by that size help make the College the perfect host for such research. "Not only is geology involved, but biologists are involved and the Environmental Science and Policy Program is involved," Hancock said.

Kaste agreed. "There is a social part, a scientific part and a political part," he said. "We can find whatever we are going to find but if we don't find a way to convey that information to policymakers then it's all for naught.

"We may find some interesting things in a year or two," he continued, "and I have a feeling it's going to open up a few cans of worms here and there."