Hydrogeology of the Little River Animal Agriculture Environmental Research Unit and Impacts of Dairy Operations on Groundwater

This thesis describes the development of an integrated hydrogeologic/hydrologic site assessment and groundwater/surface water quality monitoring program at the University of Tennessee – Little River Dairy Farm, located near Townsend, TN. Hydrologic/hydrogeologic investigations of streams and groundwater at the site have been underway for more than 5 years, and these are expected to provide background data for assessing impacts of dairy wastes. The lower half of the ~180 ha site consists of low-relief fields used for row crops, which are underlain by 4 – 9 m of alluvial deposits on top of black shale or limestone that include sinkhole features. The fields are bounded on two sides by the Little River and on the third side by Ellejoy Creek, which is on the state’s 303(d) list for impairment by nutrients, sediment and fecal microorganisms. These fields are now being fertilized with treated dairy wastes and are the main area of concern for offsite migration of contaminants through groundwater, drainage ditches and a tile drain system. Long term water quality monitoring of runoff, streams, drainage ditches and groundwater is planned, with the intent of measuring environmental impact of dairy operations and testing the effectiveness of different management practices.

Research findings indicate groundwater flow systems move toward the central ditch, Little River and Ellejoy Creek. Well hydrographs show rapid recharge in the floodplain. Geochemistry shows seasonal and short term variations, which are consistent with rapid recharge. Nitrate levels vary across the floodplain and in a few cases appear to be increasing slightly. E. coli is present before and after application of manure and major sinkholes could provide fast pathways to the Little River.