ADDRESSING WATER-MANAGEMENT ISSUES IN WISCONSIN’S CENTRAL SAND PLAIN USING A GROUNDWATER FLOW MODEL

Concerns about increasing use of groundwater and declines in streamflows and lake levels in Wisconsin’s central sand plain have motivated the development of modeling tools to help inform local water-management decisions there. The Little Plover River basin in Portage County, WI has a long history of groundwater/surface water interaction studies. Declines in the river flow and subsequent establishment of public rights flows motivated the Wisconsin DNR to commission a modeling project using state-of-the-practice groundwater science to explore water management options for the Little Plover watershed. The resulting model and analyses may serve as a prototype for addressing similar issues in wider areas of the state.

A transient MODFLOW model of the region uses up-to-date hydrogeologic observations, monthly water-use records, and temporally and spatially variable estimates of evapotranspiration and recharge. After calibration, we are implementing a linked groundwater management tool (GWM) to evaluate optimal solutions for alternative water-use scenarios (maximize withdrawal while minimizing stream and water table declines). Using these techniques and science for decision making is an important project objective. Critical to that effort is stakeholders gaining trust that the science used can fairly represent various viewpoints, and can adequately evaluate their concerns and theories of how groundwater and surface water are connected. Accordingly, our team has participated in numerous public meetings and outreach events with local stakeholders and regulatory officials. In this way, the overall project goal represents not only the interface between groundwater and surface water, but also the interface between science and policy.