Kentucky Geological Survey Report of Investigations


To prevent or reduce the contamination of ground water from agricultural sources, Best Management Practices (BMP’s) such as land-use changes, modifications to control surface runoff, various tillage methods, variations in rates and kinds of chemical applications, and handling procedures for chemicals are being employed and analyzed for effectiveness. The effectiveness of a BMP is often estimated before implementation by evaluating the BMP through the use of computer simulation models. The interactions between surface water and ground water that are unique to karst terranes are not incorporated into the frequently used predictive models. The purpose of this study was to document the impact of topographic data resolution on model input and performance in a karst setting.

An analysis of the impacts of topographic data resolution on data collection and output for the AGNPS computer model revealed that the sinkhole drainage area for two karst catchments located in the Blue Grass Region of central Kentucky is approximately doubled when using a 2-ft contour interval instead of a 10-ft interval. This doubling of the subsurface drainage was caused by a threefold increase in the number of sinks identified on the 2-ft contour interval map. The increase in the subsurface drainage was the most significant factor affecting model results, and resulted in significant differences between predicted runoff volumes, peak runoff rates, sediment yields, and nutrient yields for 2-ft contour interval data compared with 10-ft contour interval data.

Publication Date



Series XI

Report Number

Report of Investigations 13

Digital Object Identifier (DOI)

Notes/Citation Information

© 1998 University of Kentucky