Geophysical site assessment in karst terrain: A case study from southwestern Missouri

Abstract

A 110 acre study site in karst terrain in southwestern Missouri was investigated to assess suitability for landfill expansion. ERT, MASW and core hole data were acquired on the site with the objectives of identifying any karst features that could potentially pose a threat to an overlying landfill, mapping variable depth to the top of rock, and mapping the probable flow pathway(s) of groundwater from the site to both a proximal spring and a proximal creek. Top of rock was readily mapped on the acquired ERT data, except in those areas where shallow bedrock was anomalously moist, such as beneath drainage ditches and surface flow pathways. In areas where bedrock was anomalously moist, depth to top of rock was more reliably estimated using the MASW method. Karst features that could affect the stability of an overlying landfill were not imaged on the geophysical data. Dye testing was performed to establish connectivity between the site and the proximal spring. Probable flow pathways from the site to the spring and the creek were identified.