Delineation of Flow Paths, Capture Zones and Source Areas, Allequash Basin, Vilas County, Wisconsin

There are numerous interconnected lakes, streams, and wetlands in Wisconsin that are well connected to the groundwater system. Consequently, the chemistry of groundwater may greatly influence the chemistry of surface waters. Therefore, the testing of tools that can aid in identifying the source areas of recharge waters and the geologic controls on groundwater chemistry is crucial to understanding and protecting both groundwater and surface water. In the proposed study, groundwater flow paths along two transects within the Allequash basin, a sub-basin within the Trout Lake watershed located in Vilas County in northern Wisconsin, will be delineated and the geologic factors controlling the chemistry of groundwater along these paths from point of origin to discharge point will be investigated using isotope tracers and major ion chemistry. Also, an existing three-dimensional groundwater flow model will be modified to delineate lake capture zones and characterize seasonal and long-term chemical variability. This project is being done in cooperation with the Wisconsin Long Term Ecological Research (LTER) program and the Water, Energy, and Biogeochemical Budgets (WEBB) program of the USGS and results of this study will be used by both groups. Currently, the U. S. EPA STAR funding is investigating the effects of carbon quality on metal complexation within the basin, and the University of Wisconsin System is funding work on the importance of hyporheic processes on mercury cycling. The results of the groundwater analyses proposed in this study will enhance these investigations. This study will also be useful to local and state officials in efforts to understand and mitigate the effects of development and urbanization in Northern Wisconsin’s Lake District.