COMPILATION OF NATIONAL-SCALE KARST DATA BY THE U.S. GEOLOGICAL SURVEY WITH EMPHASIS ON THE SOUTHEASTERN UNITED STATES

The U.S. Geological Survey KARST (Karst Applied Research Through geologic mapping) Project is producing a new national karst map of the United States in cooperation with the National Cave and Karst Research Institute (NCKRI) and the National Speleological Society (NSS). This map will replace the national atlas karst map of Davies and others (1984). As a GIS-based map, improvements in precision and utility will be inherent to this product. In the eastern United States the extent of outcrop of soluble rocks provides a good first-approximation of the distribution of karst-prone areas. Our approach to producing a new karst map is to first compile a soluble rock map derived from various data sources, primarily state geologic maps. The potential karst areas derived from this map are then subdivided based on regional styles of karstification inherent to those rocks. Criteria are being developed for further refinement of the map units including the distribution and density of cave, sinkhole, and other karst features. Issues complicating the compilation and classification process include: 1) unevenness in spatial precision and lithologic classification between the various geologic maps; 2) lack of easily obtainable statewide and region-wide karst data, especially cave locations; and, 3) recognition of key, non-lithologic factors affecting the development and distribution of karst features. Over the past four years, we have organized three regional workshops with various state geological surveys and other interested parties. The outcomes of these workshops include the establishment of personal contacts, offers of data support, suggestions for construction of the map, and regional perspectives on karst-related issues. One of our next goals is to find a way to bridge a current disconnect between portraying and serving national-scale data produced by the U.S. Geological Survey and data owned by other national, state, and, local groups. A new karst digital data portal sponsored by NCKRI offers a potential framework for integration of data sets of all resolutions from national to local scales.