LAND-USE AS AN INFLUENCE ON RUNOFF GENERATING PROCESSES: A COMPARISON OF AGRICULTURAL AND FOREST LAND-USES IN THE SOUTHERN APPALACHIAN MOUNTAINS

The hydrological processes giving rise to runoff on relatively undisturbed, vegetated hillslopes have been extensively studied and are reasonably well understood. However, the proportion of land that can be considered relatively undisturbed is steadily decreasing as human land use increases in response to the demands of a rapidly growing population. As land use expands into mountainous headwater catchments where many major river systems begin, it becomes prudent to examine the potential influence of land use on runoff generating processes. We investigate the relationship between land use and runoff generation on hillslopes within headwater catchments of the Upper Little Tennessee River Basin in the southern Appalachian Mountains as a component of the Long Term Ecological Research (LTER) program at Coweeta Hydrologic Laboratory. Using hydrometric data and stable isotopes of oxygen and hydrogen as conservative tracers for precipitation, groundwater, and soil water we characterize subsurface runoff generating processes along the hillslope-to-stream continuum. The influence of land use on these processes is analyzed through comparison of data from sites representing two of the dominant land use types in the southern Appalachian Mountains. Preliminary results, based on data collected since August 2011, are presented here.