CENTRAL FLORIDA LAKES STUDY: EVIDENCE FROM 1973 TO 2006 LANDSAT MSS/TM/ETM IMAGES

Most of Central Florida lakes which are relics of sinkholes and have experienced isostatic uplift driven by karstification show an interesting evolution. Lake level fluctuations in the counties of Polk, Highlands, Hardee, Osceola, and Okeechobee in central Florida were studied using a set of time series of Landsat (MSS, TM, ETM+) infrared imagery from 1973 to 2006. Lake boundaries were delineated using the infrared band. While overall precipitation in the area increases during the last three decades, lakes which are smaller than 1,000,000 m² tend to extinct. Despite of lake water area fluctuations, expansion, shrinking or even extinction of some lakes, most of the wider lakes show significant offset. Each of the 54 lakes, which covers more than 1,000,000 m², shows drifting-away mostly southwestward. Centroids of the lake polygons made by Geographical Information System (GIS) were used to estimate the drifting-away azimuth and offset during 1973-2006. Lakes that occur in recharge areas of the Floridan aquifer system show southwestward lake drifting-away while few lakes that occur in the discharge area show southern to southeastern lake drifting-away. The drifting-away of the Central Florida lakes may be explained by the Northern Florida isostatic uplift driven by karstification.