ANALYSIS OF LOCAL GEOHAZARDS IN RICHMOND, KENTUCKY, USING GIS

We present a GIS-based study of local potential geohazards within the Richmond, KY area. ArcGIS was used to develop several different maps using a 10m DEM and KRG data, in order to do topographic and geologic analysis of the area. Joint orientations of the bedrock were also measured and plotted on rose diagrams using the program GeoRose. Structural analysis from previous studies indicates a tectonically active geologic history in Richmond, KY’s past. Several major fault systems are in the vicinity of the area, including the Kentucky River, Irvine-Paint Creek, and Lexington fault zones. Two minor faults also run close to the city of Richmond: the Richmond and Tates Creek faults, both striking in a west-northwest and north-northwest direction, congruent with local stream orientation. While Richmond, KY is located within the vicinity of several major fault systems, there hasn’t been any major activity along the faults since the Paleozoic era in recorded geologic history, making the most prominent geohazard affecting local areas flooding. Though urbanization of the city of Richmond plays a significant role, geologic and topographic features should be taken into account when analyzing potential flood hazards in the area. Climatologically, the state of Kentucky is considered sub-tropic. Being within the vicinity of the Appalachian Mountains, orographic uplift contributes to increased rainfall and flooding potential within the state. The city of Richmond is situated on a plateau area, with slope mostly ranging from gently to moderately sloping, away from the river. The creation of this plateau from the downcutting of the Kentucky River has created the potential for increased orographic uplift in this area. The geology of the area consists mostly of carbonates, with interbeds of shale. The soil formation from the erosion of these units consists of silty loam and clay, with the majority of the soils in the Richmond, KY being classified in hydrologic groups C and D, with a small remainder in group B, indicating the area has slow to very low infiltration rates when thoroughly wet, leading to high runoff potential. This, in addition to several other factors, including urbanization, the general topography and slope of the area, and the erodibility of local bedrock, would indicate high flooding potential within the city of Richmond.