Spatial interrelationships between lake elevations, water tables, and sinkhole occurrence in central Florida: A GIS approach

Sinkholes constitute the principal geologic hazard in central Florida. Loca l hydrogeology is recognized as an important factor in their formation. We use a GIS to investigate the spa tial relationships between hydrogeology an d sinkhole formation near Orlando, Florida. Landsat TM imagery, digital top ography, and well data are used to construct a model of the head difference between a discontinuous set of surficial aquifers and the Floridan aquifer , a regionally extensive confined aquifer. This model is quantitatively com pared to a buffer model of distance to nearest sinkhole constructed from a database of collapse events. Sinkhole occurrence is positively associated w ith regions where the head difference is between 5 and 15 m. In these regio ns, sinkholes are more common and more closely spaced than expected. In con trast, sinkholes are less frequent and farther apart than expected in regio ns of low head difference. This association of sinkhole proximity to high h ead difference demonstrates the importance of hydrostatic loads in sinkhole hazard.