2008 Model Karst Land Development Ordinance

Approximately 55 percent of Kentucky is underlain by limestone and dolostone, soluble rocks that have produced karst landscapes characterized by sinkholes, disappearing streams, springs, and caves. Over 25 percent of Kentucky is intensively karst. As Kentucky urbanization accelerates, less desirable land for building is being used, including large areas of karst topography.

The Kentucky Geological Survey has investigated many cases of property loss associated with construction on unsuitable karst sites. Karst-based environmental damage and losses tend to cluster around groundwater pollution, cover-collapse sinkholes, and sinkhole flooding. Kentucky’s karst cover-collapse losses alone are estimated as ranging from millions to tens of millions of dollars per year annually, but costs of losses tend to be largely hidden. The magnitude of karst-based losses is not recognized because individual incidents of damage, though frequent, are scattered over broadly separated areas. Property losses are typically paid by private citizens because insurance coverage is not available. Damage to public property is typically paid for from routine maintenance funds without notification of the cause.

In responding to this issue, James Currens of the Kentucky Geological Survey (KGS), in cooperation with the city of Radcliff, Kentucky, is drafting a Model Ordinance for Guidance of Development on Karst Land. Radcliff officials will provide suggestions regarding language, barriers to adoption, and adjustments needed to secure approval of the ordinance. The intent is to reduce economic and environmental damage in the years to come. Dr. Currens and the KGS will broaden the effort by contacting 25 to 50 fiscal courts, zoning commissions, Area Development Districts, and regional planning commissions over the next two years. Contacts will increase awareness of KGS expertise and the availability of its reports. Currens also intends to present the model ordinance along with case histories at a national symposium on geohazards, environmental issues, and engineering practices in karst regions.