Evaluating Water Sustainability across the High Plains Aquifer using Remote Sensing and Process-Based Hydrology Models

Abstract:

Much of the High Plains Aquifer region recently emerged from an extreme drought, which is likely to be a more common condition with projected changes in climate. Water use for agriculture greatly expanded since the early to mid 1900s, partly in response to drought. Over the last several decades there have been significant advances in the efficiency of irrigation technologies, which have changed from flood irrigation, to center pivot, then to LEPA systems. Here we present a synthesis of monitoring and modeling to investigate changes in water availability across this vast region that is dominated by agriculture. Our integrated Landscape Hydrology Model (LHM) was used to quantify hourly hydrologic fluxes including evapotranspiration and groundwater recharge across a range of observed climate conditions including the current drought. These simulations are coupled to groundwater models for the region to investigate the sustainability of current water use practices and the impacts of aquifer depletion on water budgets. Simulations are compared to measured water levels that have been synthesized across the region from presettlement to today, and with remotely sensed estimates from the GRACE satellite. Finally, we present simulations that quantify the likely impacts of projected climate changes from the CMIP5 forecasts of global climate.