In the spring of 2005 Subsurface Evaluations was contracted to investigate the entire perimeter and selected transects within the interior of a proposed above grade reservoir. Our client wanted to achieve multiple objectives with a single all encompassing geophysical survey. The primary objective was to map the depth to, thickness of, and lateral continuity of a clay confinement layer. Understanding the nature of this clay unit was critical for the design of the reservoir’s slurry wall. A secondary concern was to identify karst features within the limestone at depth. Tertiary concerns included an attempt to better understand the origin of the many surface ponds contained within the footprint of the reservoir.

Based on the multiple objectives of the client and known geologic conditions of the survey area, SEI determined that two dimensional resistivity would be the optimum geophysical method for the job. Employing 101 smart electrodes and the SuperSting R8 multi-channel resistivity meter Subsurface Evaluations was able to tackle the task of acquiring more than 10 miles of data through terrain ranging from chest deep ponds to muddy swamps, and upland forests. A combination of improvised field techniques, all-terrain vehicles, and hard work led to the successful completion of a tough project in adverse field conditions and a pleased client.