NCKRI Symposium 2: Proceedings of the Thirteenth Multidisciplinary Conference on Sinkholes and the Engineering and Environmental Impacts of Karst
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The mapping of karst features has taken on increasing importance in land use planning and zoning regulations across south east and east central Minnesota. The delineation of sinkholes, springs, and other features has traditionally depended on extensive field work, using topographic maps, and intensive networking with local landowners. The luck of the observer has also been critical as many sinkholes are rapidly refilled by landowners, concealed within extensive row crops, or hidden under tree canopies. The application of aerial tools allows mapping across large areas. Potential karst features can be identified, and indistinct or otherwise suspicious points targeted for field verification. LiDAR mapping across Minnesota now allows high-resolution imaging (1.5 m horizontal and 15 cm vertical) of small depressions in karst landscapes without interference from vegetation. These features can be visually compared to aerial photography, both visible and infrared, flown periodically by the U.S. Department of Agriculture (USDA) to verify persistence and/or reappearance of features through time. Additionally, low angle, high-resolution Pictometry(r) imagery allows overhead views from several angles to further identify and verify the genesis of a given depression. In areas with previously mapped karst features, precise locations can be compared to earlier estimates of location, which is particularly useful in applications like nearest neighbor analysis. The improved elevation mapping resulting from LiDAR work has greatly improved geologic mapping efforts based on well driller's logs. This improvement in geologic mapping allows much better correlation of karst features within stratigraphic units as well as identifying structural controls. The geologic mapping efforts are beyond the scope of this paper. While field verification is the ultimate standard, many obvious sinkholes can be identified, and numerous non-sinkhole depressions eliminated from consideration, helping focus valuable field time. -- Authors Open Access - Permission by Publisher See Extended description for more information.
University of South Florida
Alexander, Scott C.; Rahimi, Mina; and Larson, Erik, "Combining LiDAR, aerial photography, and Pictometry® tools for karst features database management NCKRI Symposium 2: Proceedings of the Thirteenth Multidisciplinary Conference on Sinkholes and the Engineering and Environmental Impacts of Karst" (2013). KIP Talks and Conferences. 36.