Karst of the Western Delaware County, Ohio, Region - Mapbook

Abstract

To locate sinks, LiDAR was used to create an ArcGIS layer that identified low, enclosed areas. These low spots were cross referenced with known karst points, bedrock geology, aerial photography (multiple sources/ages), soil maps, drift thickness, and water well logs to locate potential sinks. Suspect locations then were visited in the field, evaluated, and photographed. Through this process we quickly learned that many of the LiDAR returns were not sinks; features such as building foundations, broken field tile, steep-walled streams, and road culverts often produced enclosed areas similar in shape to sinkholes. Many of these features were eliminated using 6-inches-per pixel aerial photography and experience from field verification. The resulting map of sinkholes and collection of photographs can be used to monitor the growth of preexisting sinkholes and the development of new karst features. Furthermore, areas of land development should be carefully planned in regions of dense karst since they are highly susceptible to pollution and may subside.