Schnabel performed a high-resolution site characterization (HRSC) program for the South Carolina Department of Health and Environmental Control Underground Storage Tanks (SCDHEC UST) management division at 13 highly contaminated locations throughout the state. Since this was the first HRSC program to be performed for SCDHEC UST, we served in both a consulting and training role for state personnel.

These problematic sites had been extensively assessed and monitored for several years, some for decades, without a clear understanding of the subsurface lithology and hydrogeology as well as the horizontal and vertical extent of the contaminant plumes. We utilized HRSC instrumentation technologies including laser-induced fluorescence, optical image profiler, membrane interface probe, hydraulic profiling tool, and electrical conductivity tool. Through this method, we were able to characterize the subsurface at a very small scale. This degree of detail was needed to understand heterogeneities in the subsurface that control contaminant mass distribution, affect the fate of contaminants, and influence exposure pathways.

Our personnel conducted daily project debriefs with SCDHEC UST personnel to communicate findings and determine future areas to be assessed. This dynamic planning approach allowed for greater efficiency and ultimately cost savings. The resulting HRSC data was then utilized to create 3D models to illustrate subsurface contamination and allow conceptual site models to be refined for each of the properties. The revised conceptual site models will be used in future efforts to better design remedial approaches for the properties. We completed the HRSC program ahead of schedule and on budget, at $969,000.