Groundwater Flow and Reservoir Management in a Tributary Watershed along Kentucky Lake

Understanding groundwater flow in tributary watersheds is important for evaluating water and solute storage and inputs into reservoirs. We delineated groundwater flow at various spatial and temporal scales within the watershed of Ledbetter Creek, a third-order tributary of the Tennessee River (impounded to create Kentucky Lake) in western Kentucky. We monitored hydraulic heads in wells (primarily in the upper watershed) and piezometers (in the lower watershed) and measured the flow of a spring along the embayment where the creek enters the reservoir. Manual measurements were made at least quarterly from July 1999 to March 2002 and were made annually each April from 2002 through 2006. From May 2000 to March 2002, hydraulic heads were recorded continuously in selected piezometers. At the watershed scale, groundwater flow followed the topography, with discharge occurring along the creek and in the embayment. Hydraulic heads in piezometers responded to large storms over periods of hours to days. Longer-term fluctuations in hydraulic head reflect reservoir management in the embayment (stage increased in early spring and decreased in late summer) and seasonal variability elsewhere in the watershed.