USGS study focuses on the water of the Great Lakes Basin, the world's largest freshwater system. While there is no overall shortage of water in the system at this time, as water is taken from different parts of the system it is slow to replenish itself. This means that if groundwater is used near Milwaukee, the surrounding water levels will not significantly decrease in order to replenish that groundwater. In the Milwaukee and Chicago areas groundwater levels have decreased as much as 1,000 feet. Anticipated future pumping could decrease these levels even further.
This knowledge is very important to developers, planners, and anyone interested in the well being of the Great Lakes system. It is also part of a larger, five year research project currently being undertaken by the USGS aimed at "understanding the impact of climate variation on water use, lake levels, streamflow and groundwater levels" (USGS release). In addition to this study, the Groundwater Resources Program is also studying groundwater availability nationally. Major findings from the Great Lakes Basin pilot study can be found here.
Image credit: GLIN