Hydrostratigraphy and Groundwater Flow Model: Troy Valley Glacial Aquifer, Southern Waukesha Co., WI

Groundwater is an important resource in Wisconsin, especially in areas of southeastern Wisconsin outside the surface water divide of the Great Lakes that are prohibited from using water from Lake Michigan by the Great Lakes Compact. After decades of pumping, the potentiometric surface in the deep bedrock aquifer has dropped several hundred feet, causing some wells to draw water with high salinity and radium. Treating radium is expensive and many communities are looking for good quality shallow groundwater that would not require treatment. One possible source of shallow groundwater for these communities is the Troy Valley, a deep pre-glacial valley that was probably deepened by subglacial meltwater and is now filled mostly with glacial and related deposits.