COMMUNICATING KARST- AND SINKHOLE-RELATED HAZARDS AND RISK: EXAMPLES FROM KENTUCKY (Invited Presentation)

Karst terrain encompasses about 50 to 60 percent of Kentucky, and about 67 percent of the state’s population lives in areas potentially affected by karst- and sinkhole-related hazards. Because of extreme geologic and hydrogeologic complexities, investigation and characterization of karst hazards such as cover-collapse sinkholes are often difficult. It is therefore not surprising that communicating the potential risks posed by karst is also challenging to do in a meaningful, easily understood manner.

Over the years, the Kentucky Geological Survey has been proactive in collecting, processing, and disseminating information on karst and sinkhole occurrences throughout the state. KGS scientists have worked for decades on a series of karst and sinkhole mapping projects, and have compiled a detailed database with information about occurrences of cover-collapse sinkholes across the state. Over 350 case histories have been collected and reviewed, going back to 1997. An average of 24 new reports of cover-collapse sinkholes are received each year from private citizens who either call or email, or who voluntarily submit information using an online sinkhole reporting form. A statewide map depicting the locations of 101,632 sinkhole depressions identified using 1:24,000-scale digital orthophotographic quadrangle data was created in 2003 and is accessible online. Recently, KGS karst researchers began the process of extracting data to delineate sinkhole depressions using high-resolution LiDAR data sets, and we are systematically working to update and refine the existing sinkhole map, generally increasing the number of previously mapped sinkholes by a multiple of three in areas where the LiDAR data are used. Other products of research that have been created and published by KGS largely for the purpose of communicating information about karst occurrence, features, and potential hazards include a karst potential index map and a series of karst hydrologic maps showing subsurface karst flow paths and groundwater basin divides inferred from water-tracer tests. All of these karst research activities and products are intended to provide useful information to meet public needs in an easily understandable way.