GEOLOGIC CONTEXT OF HIGHWAY MAINTENANCE COSTS FOR ROCKFALLS, LANDSLIDES, AND SINKHOLES IN KENTUCKY

The Kentucky Geological Survey has recently completed a three-year project to document the spatial distribution of geologically related highway maintenance costs in Kentucky. The project combined the statewide detailed digital geologic map dataset developed by KGS with data from the Kentucky Transportation Cabinet on maintenance costs on highway repairs related to landslides, rockfalls, and sinkholes.

The maintenance data are derived from the Kentucky Transportation Cabinet Operations Maintenance System, a database of maintenance activities that came from highway district work orders. Seven years of data were analyzed in three phases of the project. Phase I converted the tabular data into GIS format in order to analyze costs geospatially. Phase II investigated the geologic and geomorphic context of the landslide, rockfall, and sinkhole costs in the field. Phase III included the statistical and spatial analysis to correlate maintenance costs to geologic units.

Maintenance locations were intersected with recently released high-resolution geologic GIS data to get an estimate of the level of maintenance associated with each geologic unit. The state-maintained roads layer from the Transportation Cabinet was intersected with geology to calculate the total miles of roads exposed to each geologic unit. Spatial and statistical analyses were completed in an attempt to provide an estimate of the rockfall, landslide, and sinkhole maintenance costs per mile to be expected in the future for roads on different geologic units in each of the 12 transportation districts in the state.