Subsurface Investigations

SES geologists, hydrologists, soil scientists and other environmental professionals are experienced at conducting subsurface investigations in the various hydrogeological environments of the western United States. SES professionals have experience at over 50 National Priority List sites, some the most contaminated sites in the country, and have investigated the full spectrum of chemicals of concern. From radioactive and munitions-related releases at military or Department of Defense sites, large scale manufacturing facility solvent and heavy metal releases, heavy metals and fuel spills from auto wrecking yards, metal and polychlorinated biphenyls from metal recycling operations, airport fueling or solvent degreasing operations, landfill leachate, solvents from former and operational dry cleaners, gas stations, to residential heating oil releases, our environmental professionals have effectively designed subsurface investigations and sampling and analytical plans to delineate subsurface releases. Our data interpretation software allows us to present and interpret data in three dimensions in order to fully convince project stakeholders our site conceptual models are accurate. This allows us to be assertive client advocates in agency or opposing stakeholder negotiations and to provide our engineers with the information they need to design an effective and efficient environmental remediation system.

Seattle, WA :

Following a brief historical review, SES identified the historic presence of a retail gasoline station and an automobile repair facility on a commercial property in Seattle. Using ground-penetrating radar and by conducting a survey using a magnetometer, SES was able to identify the historical presence of an underground storage tank beneath the property. A subsurface investigation was conducted based on the presence of the tank, the location of the former dispenser islands, and an adjacent operating automobile repair facility.

Our investigation identified the presence of high concentrations of gasoline, benzene, toluene, ethylbenzene, total xylenes, and chlorinated solvents in the soil and groundwater beneath the property. We entered the data into 3-D visualization software (GEMS™ and EnviroInsite™) that allowed us to distinguish the presence of a silt mound on what appeared to be the downgradient portion of the property. The silt mound forced groundwater to flow in what appeared to be an uphill direction; based on this information, we were able to design and implement a remedial system that will efficiently and effectively reduce the concentrations of contaminants both on- and off-site.