Groundwater and Climate Change: Forcing, Feedbacks, and Integrated Hydrologic Response
Colorado School of Mines
While anthropogenic climate change is significantly altering the hydrologic cycle at global and regional scales, climate change impacts on water resources will ultimately depend on interactions and feedbacks between groundwater and surface water processes, the land surface water and energy balance, and regional climate processes. Here we use ParFlow, an integrated watershed model that includes three-dimensional variably-saturated subsurface flow, overland flow, and land surface processes, to analyze watershed response under observed and perturbed climate conditions. Streamflow response to changes in temperature and precipitation is shown to differ significantly between predominately energy-limited (direct runoff) conditions compared to moisture-limited (baseflow) conditions. Similarly, the evapotranspiration response to changing climate conditions is shown to depend on feedbacks between groundwater and the land surface water and energy balance. Notably, our results demonstrate not only that local and watershed response to climate change depends on feedbacks between groundwater, surface water, and land surface processes, but that the magnitude of these feedbacks is sensitive to changes in climate. Developing effective strategies to mitigate the impacts of climate change on water resources will therefore require an improved understanding of interactions and feedbacks across the hydrologic cycle at local, regional, and global scales.