TRANSIENT GROUNDWATER FLOW MODELING USING THE FINITE ELEMENT METHOD IN AN UNCONFINED AQUIFER IN THE PIEDMONT AREA, WATKINSVILLE, GEORGIA

The USDA Agricultural Research Service has instrumented a small (~10 ha) grass watershed in Watkinsville, Georgia. It is a typical piedmont site with saprolite developed approximately 8.5 meters above the saprolite-bedrock interface. At the base of the watershed is a small wetland, with streamflow from the wetland measured by a flume. Streamflow measurements have been manually taken three days a week for eight years. Four water level recording data loggers have been installed in shallow saprolite wells set to record depth to water every 15 minutes since September 2007. A three dimensional finite element model is being parameterized to estimate saturated transient conditions at the site. This model will be calibrated using the measured head and streamflow values. These results will be used to estimate nitrate travel times to the wetland from different locations on the watershed.