Florida Geological Survey - Geology Topics
Lake Jackson Photo Gallery
On September 16, 1999, much of the central portion of Lake Jackson, a large lake on Tallahassee’s northern side, drained down an eight-foot-diameter sinkhole known as Porter Hole. Sinkholes in Lake Jackson open and drain portions of the lake approximately every 25 years. Following the September 1999 event, the FGS, in cooperation with the Northwest Florida Water Management District, Leon County, and the Florida State University Department of Geological Sciences began investigating this phenomenon. This investigation will improve our understanding of the connection between Lake Jackson and the Floridan aquifer system, which provides most of the area’s drinking water.
Shallow push cores in the vicinity of Porter Hole have been collected and are undergoing analysis, a general map of greater Lake Jackson has been compiled showing conditions resulting from the natural draw down event, and the Porter Hole area has been surveyed and mapped. Tom Scott (FGS) has explored Porter Hole Sink with a variety of scientists, state and local officials, and media representatives, affording the opportunity for down hole measurements and photography. The sink, which occurs in a 15 feet deep depression in the lake bed, is approximately eight feet in diameter at its top and is about 50 feet deep, below the average lake bed. The sink consists of a series of convoluted passages through the limestone, with various conduits intersecting the main sink. The FGS has drilled four vertical core holes to depths from 105 feet to 119 feet below the lakebed. Interpretation and analysis of the cores continues and will be published by the FGS upon completion.
Lake Jackson photo gallery includes a collection of interior and exterior images of the sinkhole taken by Tom Scott (FGS) during the investigation of the drawdown.
Last updated: February 09, 2010
903 W. Tennessee Street
Tallahassee, Florida 32304
850-617-0300 (phone) 850-617-0341 (fax)