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. Local hydrogeology is recognized as an important factor in their formation. We use a GIs to investigate the spatial relationships between hydrogeology and sinkhole formation near Orlando, Florida. Landsat TM imagery, digital topography, 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 compared to a buffer model of distance to nearest sinkhole constructed from a database of collapse events. Sinkhole occurrence is positively associated with regions where the head difference is between 5 and 15 m. In these regions, sinkholes are more common and more closely spaced than expected. In contrast, sinkholes are less frequent and farther apart than expected in regions of low head difference. This association of sinkhole proximity to high head difference demonstrates the importance of hydrostatic loads in sinkhole hazard.