A geographic information systems methodology for the identification of groundwater recharge areas in Waukesha County, Wisconsin

A Geographic Information Systems (GIS) based comparative methodology to delineate groundwater recharge areas was developed to identify recharge areas in Waukesha County, Wisconsin. Rapid growth in the county has increased fresh water demand, and groundwater levels have dropped between 45 and 60 meters. Recharge areas are particularly important to protect because misuse of these areas can lead to depletion of potable water supplies and increased groundwater contamination. Recharge potential mapping is an important step towards protecting regional groundwater resources. This study provides a method that can be implemented by local and regional planning boards to protect water resources. Precipitation, temperature, soil and land cover data were used to generate percolation, surface runoff and root-zone water capacity maps, which were used as proxies for recharge. These maps were then combined and ranked according to recharge potential, creating a recharge potential index suitable for land use planning decisions. Application of this method to Waukesha County, developed herein, indicates that the greatest source of recharge is the Kettle Moraine plateau in the western part of the county. Other regions with high recharge potential include those areas where interlobate moraines and drumlins are found at the surface.