TITLE: Modeling groundwater-lake interactions for management of a highly stressed temperate aquifer in the Central Sands Region of Wisconsin.
ABSTRACT: In the temperate upper Midwest of the US, where groundwater and surface water are intimately connected, the overall water balance maintains abundant volume, but stress is expressed through impacts to streams, lakes, and springs. In Wisconsin, the state legislature mandated a study to evaluate the relationship between groundwater withdrawals and lake levels in the intensive agricultural Central Sands region of the state where irrigated agriculture is a dominant land use. The project quantified the impact pumping has on three study lakes in the area and identified potential remedies to reduce those impacts. In support of that goal, we established a modeling framework that could represent regional boundaries at a coarse scale while simultaneously representing lake geometry and physical properties at a much finer scale. This was accomplished through a combination of static and dynamic model linking taking advantage of the multi-model capabilities in the MODFLOW 6 framework. Recharge was simulated using the Soil Water Balance (SWB) code including simulating irrigation following the FAO-56 crop evapotranspiration technique. History matching using reported pumping and observed weather from 2012-2018 was performed to tune parameters.
With representative models created for three specific lakes, we performed a comparison of lake level history under three assumed land use configurations: current agriculture, no agriculture, and maximum future agriculture. All three configurations were simulated over a representative climate history of 40 years to compare potential impacts to lake ecology and recreation. The resulting lake elevation histories were then evaluated by a multi-disciplinary team to evaluate significance of impacts. The results of this work could directly inform groundwater management in Wisconsin going forward.
BIO: Dr. Mike Fienen is a Research Hydrologist specializing in groundwater modeling, parameter estimation, statistical and probabilistic modeling, and uncertainty analysis at the USGS Wisconsin Water Science Center in Middleton, Wisconsin USA. A native of Minnesota, Mike earned a B.A. in Geology with a Russian Language minor from Macalester College in 1993. He then embarked on a consulting career where he conducted field investigations throughout the US and the Pacific Ocean and performed groundwater and air dispersion modeling studies. Mike earned a MS and PhD in the Environmental Fluid Mechanics and Hydrology program in the Civil and Environmental Engineering Department at Stanford University in 2002 and 2006. After a postdoc, Mike began his USGS career.
Mike’s research mission is to provide decision-making support for environmental managers that considers uncertainty in all aspects of decisions and strives to extract the most information from the data. This mission is expressed through the main research threads of model calibration and inference of environmental systems. Specific applications include groundwater quantity and quality; statistical inference and prediction of recreational water quality on beaches; mercury in water and fish; and the groundwater and habitat impacts of sea-level rise. In support of these threads, aspects of computational efficiency, statistical analysis, and data management also play important roles.