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Winter 2002/2003
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Possible Interstate 66 Routes Scrutinized

Karst GIS Advances in Kentucky

By Lee J. Florea, I-66 Special Project, National Speleological Society, University of South Florida; Randall L. Paylor, Kentucky Speleological Survey, Kentucky Geological Survey; Larry Simpson, National Speleological Society; Jason Gulley, Purdue University

  Karst: terrain with distinctive characteristics indicative of bedrock dissolution by groundwater. Karst features include sinkholes, sinking streams, and caves.

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Karst map of Kentucky showing study areas.

Karst is an integral part of the landscape of Kentucky, with approximately 55 percent of the state underlaid by karstic limestone in three of seven physiographic provinces and along the margins of the eastern and western Kentucky coal fields. The abundance of karst in Kentucky affects everything from the state's biodiversity to the history of human settlement. Widespread and intense karstification of the region poses tremendous environmental impact issues due to continued population growth and industrialization.

Interstate 66 and Development Issues

When the Kentucky Transportation Cabinet (KTC) in 1999 unveiled possible routes for the section of Interstate 66 between London and Somerset, Kentucky, karst researchers became concerned. This proposed corridor traversed undeveloped woodlands inside and outside the Daniel Boone National Forest, crossed several high-quality watersheds, and threatened severe damage to cave and karst resources. In response, the I-66 Special Project of the National Speleological Society (NSS) in cooperation with the Sloans Valley Conservation Task Force, Kentucky Heartwood, Somerset Pulaski County Concerned Citizens, and dozens of other organizations initiated an extensive and cooperative karst data gathering campaign in the region.

The effort focused on collecting, maintaining, and presenting a GIS of karst resources in Pulaski County, Kentucky, using ArcView software. The first level of data included a point location database of cave entrances and associated karst features provided by locals and members of the caving community. A second layer of information included scanned and georeferenced (registered to real-world coordinates) cave maps. From these raster images, polygons outlining the passages were digitized to display regions in which surveyed caves were known to lie underneath the surface. A third layer of information included sinkhole polygons digitized from depression contours on 7.5-minute topographic quadrangles. The final layer of information in the GIS was vector representations of the corridor alternatives for the I-66 Special Project. This information was provided by KTC. All data was created using NAD83 datum and the Kentucky State Plane South 1983 coordinate system.

The data developed by this effort was used in several ways. Overlays of the corridor alternatives with a 1,000-foot buffer combined with conduit polygons, sinkholes, and cave entrance data were used to determine potential karst impacts for each alternative. Conduit polygons and sinkhole coverages for the area affected by the proposed corridors were provided to KTC and its consultants for incorporation in a second planning study (released in June 2000) to address the concerns raised by the first. Images produced using the data were presented in publications and at various presentations throughout the region to help others understand the concerns.

The Results

The impact of the GIS work to date by the I-66 Special Project, NSS, in Kentucky has been significant. Due to a combination of public opinion and evidence provided through karst GIS development, the second planning study for I-66 recommended a more northerly corridor, which avoided the primary environmental problems of the earlier route including many known cave and karst resources.

The efforts of the I-66 Special Project have opened the door to other research in the region, including a cave-cricket/beetle predatation study, cave diving exploration in regional aquifers, and geomorphic studies of regional caves. Other research stemming from this collected data has detected evidence of a previously unknown fault though sinkhole and conduit alignments.

The Kentucky Speleological Survey

Because of the cooperative atmosphere of the I-66 research, a desire to gather and organize the extensive karst data for all of Kentucky prompted the formation of the Kentucky Speleological Survey (KSS) during 1999 and 2000. KSS was formed to serve as a statewide database and repository for cave- and other karst-related data. The establishment of KSS is an important step toward proper planning and zoning in karst regions, implementation of best management practices for karst, and advancing the state of knowledge about karst through research.

The utilization of GIS as an integral component of KSS's data gathering and archiving activities was emphasized during organization. Currently, KSS uses ArcView linked to Access databases and spreadsheets to manage all its spatial data. This allows the user to link multimedia data such as narrative files, scanned maps, and cave photographs to the primary spatial index of feature locations. This will provide the framework needed for an eventual, fully integrated database of material without the need for paper copies.

Sinkhole Digitization Project

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Sinkhole distribution for Western Kentucky area.

An example of one of the issues that KSS is addressing arose during the work in Pulaski County for the I-66 efforts. The interstate development problem illuminated the need for a detailed statewide sinkhole delineation. Following a review of the results of the I-66 Special Project, NSS, and considering the ongoing groundwater investigations occurring at the Kentucky Geological Survey (KGS), a decision was made to complete a sinkhole digitizing effort for all of Kentucky on a 1:24,000 scale.

The sinkhole digitization required that several data issues be addressed. These included the representation of complex uvalas (sinkholes with multiple sink points), differences in contour intervals between topographic quadrangles and their effects on data resolution, and manipulation of United States Geological Survey hypsography files.

The statistics generated by the KSS sinkhole digitization project are impressive. Nearing completion, more than 62,000 sinkholes have been digitized to date for Kentucky. The combined area of these polygons suggests that approximately 3 percent (more than 1,200 square miles) of the surface of Kentucky lies within a topographically mapped sinkhole. The sinkhole digitization effort has also helped KGS develop more effective dye tracing methods due to the recognition of regional sinkhole lineaments.

The completed statewide sinkhole coverage will be published through KSS and KGS and will include a descriptive folio and data CD-ROM. The coverage will be useful for many purposes including planning, resource management, cave and karst research, groundwater studies, and statistical analysis.

Continuing Study

A 3D model of the Sloans Valley Cave System is being developed using ArcView with the ArcView Spatial Analyst and ArcView 3D Analyst software extensions. The GIS is nearing completion and will be used to model water levels, cave stream and reservoir water mixing, siltation, and landfill runoff routes through the cave.

A longer version of this article appeared in the Journal of Cave and Karst Studies (April 2002, Vol. 64, No. 1). To read the complete article with references, visit For more information, contact Lee J. Florea, Kentucky Speleological Survey, Inc. (e-mail:, tel.: 813-784-8490, fax: 813-974-2654, KSS Web site:

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