INTEGRATED WATERSHED MODELING: APPLICATIONS TO CLIMATE CHANGE IMPACT ANALYSIS

Numerous studies have shown that land-atmosphere feedbacks play a significant role in regional climate. More recently, several studies have shown that land-atmosphere feedbacks, the land surface energy balance, and the hydrologic response to climate change are all dependent on interactions between groundwater and the land surface. Here we describe the latest version of ParFlow, a unique, three-dimensional, variably-saturated groundwater flow model with fully integrated vegetation and overland flow processes. We then use ParFlow to investigate the role of groundwater-land surface interactions on regional climate and the regional response to climate change over the Little Washita watershed in central Oklahoma, USA. Results demonstrate that impacts of changes in temperature and precipitation on the local water balance, surface-atmosphere interactions, and surface climate are strongly dependent on groundwater-land surface interactions. Results suggest that accurate assessment of the hydrologic and water resources impacts of global climate change require a fully-integrated approach that captures the two-way interactions between surface and subsurface hydrology, the land surface energy balance, and regional climate.