Applications of Aquifer Vulnerability Assessments in Florida

With more than 700 springs, thousands of cave systems and tens of thousands of sinkholes, Florida's aquifers are among the most intrinsically vulnerable in the United States. Stressors on the quality and quantity of the groundwater include a statewide population of ~18 million that increases at a rate exceeding 1000 people per day. Moreover, the source for more than 90% of the state's drinking water is groundwater.

Aquifer vulnerability assessments in Florida have become important resources for growth management, land-use planning and water management professionals as they implement science-based policy at the local and state level. Applications of the assessments include defining levels of sewage treatment, stormwater management, density of residential development and delineation of protection zones for springs, groundwater recharge and wellheads. Use of aquifer vulnerability maps is also part of the emergency protocols for animal carcass disposal in the event of a major storm or viral outbreak (e.g. avian influenza). The assessments are also being integrated into development of best management practices for various land-uses.

Maps utilized for these activities are the product of the Florida Aquifer Vulnerability Assessment (FAVA), which is framed on a GIS-platform using the weights of evidence component of ESRI's ArcGIS Spatial Data Modeler. This data-driven, Bayesian probabilistic model applies spatial hydrogeologic inputs such depth to water table, proximity to karst features, soil permeability and confinement thickness, combined with ambient water-quality data from wells to yield a map of relative aquifer vulnerability to surface sources of contamination. Successful implementation of the maps is due in large part to membership of the project's technical advisory committee, which included representatives from key state agencies that would be the end-users of the model outputs. Numerous presentations of the FAVA project at the state and county level and at trade meetings enhanced visibility and application of the maps.