DEVELOPING A SINKHOLE DATABASE FOR MONTGOMERY COUNTY, TN

In Montgomery County Tennessee, clayey soils overlie Warsaw and St. Louis limestone formations, which formed approximately 330 million years ago. Millions of years of water moving through the subsurface and chemically weathering these limestones created underground cave and conduit systems into which the overlying clayey soils collapse, forming a sinkhole. Sinkholes present many problems in the region, including road and building collapse, and groundwater contamination. To aid developers and city planners in siting future developments and waste disposal in Montgomery County, outlines and long and short axes of sinkholes were drawn on a set of United States Geological Survey topographic maps. During this process sinkholes are also labeled, and the orientation of the long axes recorded. These maps will then be digitized and constructed into one large map using QGIS. The digitized topographic map will then be overlaid on an aerial map and aligned using the coordinates from each quadrangle. Then the length of the long and short axes of each sinkhole will be measured with QGIS’s line tool. Additionally, the location and distance to the nearest neighboring sinkhole, and each sinkhole’s area will be calculated. Analysis of this data will help determine if or how these sinkholes are connected and the potential for future collapse, and the digital map will serve as a resource to Montgomery County.