Preliminary Development of Sinkhole Hazard Charts for Stormwater Pond Flooding in the Silver Springs Recharge Basin, Marion County, Florida, USA

The Silver Springs State Park in Marion County has played a tremendous role in the development of Central Florida’s national image of beautiful natural resources and unique eco-tourism attractions. However, with an increase in urbanization in the surrounding area, the groundwater emitted from Silver Springs has seen a drastic increase in pollutant concentrations, in turn severely affecting the water quality and ecosystems within the Silver River. A major contributing role for the increase in groundwater pollutants is the increase in sinkhole occurrences within the recharge basin for the springs. Sinkholes essentially provide a “direct connect” to the Floridan aquifer, allowing nutrient-rich surface water to enter the aquifer without any natural filtering or biological degradation processes. This study investigates the influences of subsurface conditions to sinkhole formation within the area surrounding Silver Springs through implementing in situ soil laboratory testing and numerical modeling. Through simulations of various subsurface and hydrogeological conditions, stability hazard charts were developed to estimate the critical subsurface and stormwater conditions leading to a potential sinkhole. This methodology presented will greatly benefit future decision making when designing stormwater management structures (i.e., ponds or roadway swales) to ensure less potential of pollutant groundwater entering the groundwater aquifers-particularly in a sensitive environment such as Silver Spring’s.