A spatio-temporal analysis of groundwater level changes in relation to urban growth and groundwater recharge potential for Waukesha County, Wisconsin

Abstract

The main objective of this study was to spatially and temporally analyze groundwater level changes using geographic information systems and spatial analysis with respect to urban development, groundwater water withdrawal, and groundwater recharge potential. The study focused on Waukesha County in southeastern Wisconsin, where urban development has been accelerating while groundwater has been declining during the last several decades. We analyzed data about groundwater withdrawal, groundwater level, land use/land cover, and precipitation utilizing correlation analysis, Geographically Weighted Regression (GWR), land-use change analysis, and map overlay. As a result, we found that (1) Urban areas increased faster in areas with high recharge potential than in areas with low or moderate recharge potential, (2) The effect of urban growth on groundwater level is highly variable by time and space, and (3) The changes in groundwater level are strongly related to the spatial distribution of groundwater withdrawal. The study pinpoints the need to consider the spatial unevenness of groundwater withdrawal in understanding the changes in groundwater level and groundwater recharge potential for better managing groundwater resources.