Using the hydrologic model mike she to assess disturbance impacts on watershed process and responses across the Southeastern U.S.

­­ A clear understanding of the basic hydrologic processes is needed to restore and manage watersheds across the diverse physiologic gradients in the Southeastern U.S. We evaluated a physically based, spatially distributed watershed hydrologic model called MIKE SHE/MIKE 11 to evaluate disturbance impacts on water use and yield across the region. Long­term forest hydrologic data from a southern Appalachian Mountain and a lower coastal plain watershed in South Carolina were used as model inputs. The model captured the temporal and spatial dynamics of shallow groundwater table movement and streamflow. Results suggest climate change and tree removal would have pronounced hydrologic effects; especially during dry periods. We also found that the data parameterization for even small scale distributed watershed­scale modeling remains challenging where spatial subsurface characteristics are often not known. The global change implications on hydrologic processes and response to in the two landscapes are discussed. INTRODUCTION Over half the land mass of the Southeastern U.S. is forested. The region has high biodiversity, and favorable climate for plant and animal growth, and human habitation. However, forest ecosystem services are threatened by global changes that include population growth, urban sprawl, climate change, and other natural and human stressors (Wear and Greis, 2004). These current and future biotic and abiotic changes will have long­term impacts on watershed ecosystems through their direct effects on the water cycle within the region (McNulty and others 1998). Although forested watersheds provide the best water, potential water quantity and water quality degradation from intensive forest management practices, landuse changes, wildfires and other disturbances is of regional concern (Swank and others 2001). Watershed management and restoration practices, such as Best Management Practices (BMPs) require an accurate understanding of the basic controlling factors of hydrologic processes at a watershed­scale across the diverse physiologic gradients in the Southeastern U.S. (Sun and others 2004)