LEVERAGING DETAILED GEOPHYSICAL AND HYDROSTRATIGRAPHIC DATA TO INFORM A REGIONAL FLOW MODEL IN A FRACTURED DOLOMITE AQUIFER

Preferential flow paths and rapid groundwater movement in the fractured Silurian dolomite aquifer present challenges for understanding, simulating, and protecting the groundwater system. Because the hydrostratigraphy and karst features often strongly influence flow patterns in these settings, understanding the geologic context is imperative for producing realistic simulations of flow. Near Sturgeon Bay, Wisconsin, the dolomite aquifer is characterized by a series of laterally-continuous high-permeability layers correlated to stratigraphy based on detailed geophysical data and flow logging (Muldoon et al., 2001). This hydrostratigraphic framework was successfully incorporated into a groundwater flow model for Sturgeon Bay (Rayne et al., 2001).

A new groundwater flow model is being developed to expand and test the same hydrostratigraphic framework in Kewaunee and southern Door Counties, Wisconsin. Recently-collected airborne electromagnetic (AEM) surveys in this region (Minsley and others, 2022) and associated interpretations of stratigraphy will be leveraged to improve model layering. Preliminary model results will be used to evaluate areas of uncertainty to inform targeted data collection, followed by testing and final model calibration. Developing a geologically-realistic flow model for this sensitive aquifer will improve the ability of water resource managers to evaluate vulnerability to nonpoint contamination and how the groundwater resource will react to future climate and anthropogenic stress.