URBAN DEVELOPMENT on KARST: LESSONS LEARNED..OR NOT? A CASE STUDY IN BOWLING GREEN, KENTUCKY, USA

The city of Bowling Green, Kentucky (population 56,600) is a focal point for the convergence of groundwater flowing beneath the sinkhole plain of Warren County, Kentucky and has long suffered the impacts associated with urban development on karst. Groundwater contamination of the local karst aquifer from domestic sewage disposal systems has been a long-term issue for area water quality. Rearrangement of the natural surface drainage by many urban development projects has resulted in numerous regolith collapses throughout Bowling Green and Warren County in general. Continued urbanization has significantly increased impervious surface areas, increased storm water runoff, and as a consequence increased sinkhole flooding. Though the routes of subterranean conduit drainage have been identified with dye tracing, cave mapping, cave radio-location and geophysical methods, roads and other infrastructure continue being constructed in high risk areas and at least one significant bedrock collapse into the karst aquifer has occurred. In the mid-eighties toxic vapors were found leaking into local homes and buildings. They were eventually identified as leaks from underground storage tanks owned by local industries. Though leaks were repaired and toxic factory wastes were no longer discharged into the karst aquifer, the city continues to have sporadic problems with fume leaks. Extremely high levels of radon, which are a natural occurrence in karst areas, remain a hazard that must be remediated in many residences in the city of Bowling Green. Despite the large body of information, literature, and maps generated by the Center for Cave and Karst Studies, the Crawford Hydrology Laboratory, and Hoffman Environmental Research Institute, that identifies the impacts of urbanization on Bowling Green’s karst, these environmental issues are still addressed in retrospect rather than proactively by the city, local industries and developers.