Effects of climate change and high-capacity wells pumping on streamflow and groundwater elevation in Northeastern Wisconsin

The number of high-capacity wells has increased substantially in the state of Wisconsin, United States, and concerns have been raised about their impact on both groundwater levels and streamflow. At the same time, Wisconsin's annual precipitation and temperature have been trending upward over the last 30 years and both are predicted to increase into the middle of the twenty-first century. The study demonstrates the simultaneous effects of climate change and groundwater withdrawal from high-capacity wells by employing two simulation models: the Soil & Water Assessment Tool (SWAT) and the USGS Modular Hydrologic Model (MODFLOW). SWAT was used to simulate the change in the recharge rate, and MODFLOW was then used to simulate the change in hydraulic head. The SWAT model predicted that future increases in Wisconsin's annual precipitation (5%) will cause increases in both groundwater recharge (16.7%) and streamflow (14.1%). The future increases in temperature (approximate to 3 degrees C), however, are predicted to leave the state with a net deficit in both streamflow (- 23.4%) and groundwater recharge (- 19.6%). In addition, the MODFLOW model predicted a mean head elevation decrease of over 2 m due to changes in the climate and an additional decrease (approximate to 3 m) in groundwater elevation surrounding high-capacity wells due to predicted increases in annual withdrawal rate.