HYDROLOGIC RESPONSE TO GROUNDWATER WITHDRAWALS IN THE UPPER WABASH RIVER

The state of Indiana does not experience wide-spread water scarcity as water resources are currently sufficient. It receives more than 1000 mm of precipitation each year and out of that, in some areas more than 250 millimeters recharge groundwater aquifers. Groundwater resources have traditionally provided a buffer for cities and farms against drought. However, with increasing drought frequency, it is possible that groundwater conflicts during periods of scarcity will increase in the future. Traditionally, there is a tendency to underrepresent the human aspects of the water cycle such as groundwater withdrawals in large-scale simulation models because they tend to be site specific and small in scale. In this work, a macroscale hydrological model, the Variable Infiltration Capacity (VIC) model, is modified to represent the effect of water withdrawals and groundwater storage. Aquifer storage is represented through the inclusion of three additional subsurface layers in the VIC model and a new groundwater flow pathway. Observed monthly-average groundwater withdrawals from significant groundwater withdrawal facilities within the Upper Wabash River Basin are extracted from each 1/8 degree grid cell of the VIC model. Variability in groundwater level (water table) and streamflow response are quantified and evaluated against observed data throughout the basin. Future freshwater withdrawals are projected based on climate, population and energy projections and incorporated into model simulations of future conditions to quantify variability in the water table and streamflow response for different future water use scenarios. Locations of potential water stress with projected water withdrawals for the Upper Wabash River Basin will be explored to provide valuable information for improved response to short-term water limitation in the future.