Benjamin Schwartz, a Ph.D. student in geosciences in the College of Science, who is from Doe Hill, Va., in Highland County, is using an innovative technique to characterize ground water movement in sinkholes. His goal is to recommend management strategies to reduce contamination of aquifers in regions that are rife with sinkholes. Hurricane Ivan's downpour in Southwest Virginia allowed him to measure changes in underground water over a short 4-day period.
Schwartz will present his findings at the 116th national meeting of the Geological Society of America in Denver on Nov. 7-10.
Sinkholes generally form over limestone and dolomite. That rock dissolves and the earth on the surface subsides. Water from the sinkhole either seeps into the subsurface or runs in through a fissure or cave opening and rapidly enters the aquifer.
"People up and down the Shenandoah Valley get their water from aquifers," Schwartz said. "Often, these aquifers are contaminated. Sources of contamination include runoff from paved surfaces or because a good portion of Virginia's agricultural land is on karst terrain. There is little filtration between surface water and karst aquifers."
Karst is a term used for a landscape where water movement is underground because of the voids in the bedrock.
Schwartz is using six sinkholes on Virginia Tech's Kentland Farm along the New River in Montgomery County to measure how water and contaminants move within a sinkhole, that is, thehydrology and chemical transport in a sinkhole. He is looking at depth to bedrock (soil thickness), slope within the sinkhole, drainage area, and land use such as wood land, crop land, or pasture ("Cattle love to stand in sinkholes.") to determine if such sinkhole characteristics indicate what is happening underground.