EXAMINING THE IMPACTS OF A LAKE-DRAINING SINKHOLE EVENT ON THE DOWNGRADIENT AQUIFER

Karst environments are hydrogeologically heterogeneous and many karst features allow for the very rapid exchange of surface water and groundwater. On June 6th, 2021, a sinkhole in Tallahassee, Florida reopened and drained a local polje-style lake, Lake Jackson. Approximately one third of the 16 square kilometer lake was emptied through the sinkhole into the Upper Floridan Aquifer. This oxic surface water is quickly being injected to the anoxic aquifer via turbulent flow through a karst conduit. The rapid change in redox state and kinetics of this flow is expected to have an impact to chemical transport in these karst environments. While this water is assumed to have moved through karst conduits, the impacts of this draining event on the surrounding matrix of the Upper Floridan Aquifer has not been studied. This project explores the responses of this sinkhole event downgradient of the lake. In one downgradient monitoring well, groundwater level, conductivity, temperature, and pH are examined to detect the signals of the sinkhole event. We attempt to find the spatial extent of the responses to the sinkhole event in the water levels of multiple downgradient water bodies and monitoring wells. One such of these is Wakulla Springs, a first order magnitude karst spring that is expected to have water sourced from the lake and the sinkhole event. A proposed dye tracing experiment from the sinkhole to springs will hope to corroborate these findings.