Environmental Geophysics
Olson performs geophysical investigations for environmental site surveys. Our clients’ needs range from detection of subsurface metallic objects and features prior to intrusive activities, imaging of geologic conditions conducive to contaminant migration, to addressing changes in the subsurface during remediation. Each site and each objective is always different for environmental projects. Many projects are very straight forward with detection of buried metallic objects, both large and small (e.g., UST, pipes, UXO/MEC). Some projects require very intricate methods to image complex geology or hydro-geologic characteristics involving the lateral or vertical transport of contaminants.
Rarely, are geophysical methods capable of direct detection of the contaminants; however, free product in the form of LNAPL or DNAPL can sometimes be imaged with the right subsurface conditions and the right application of methods, including even multiple geophysical methods. But at the low concentrations that many compounds are considered dangerous, or defined as contaminants of concern (COC’s), there is not sufficient contrast with the soil, rock or groundwater surrounding them to be successfully imaged using geophysical methods.
Clients appreciate that we take the appropriate steps and spend time with them to understand the specific site settings, geologic and groundwater conditions, and project objectives to carefully determine the best approach to meet those objectives. It is important to note that often, when it comes to contaminant transport modeling, the geophysics does not, in fact, address the level-of-contamination but rather provides evidence of faulting for vertical migration, layers such as aquatard or aquifers which influence the lateral flow of fluids or contaminants, or of fractured rock for secondary porosity versus primary porous-flow media models.
Because of Olson’s geophysical expertise, the unique and varied objectives of environmental problems, and the wide variety of
methods available, we recommend you call to discuss what solution will best suit your site issue(s). We can tell you what should or shouldn’t be done on your project site, allowing you to decide if geophysics is the right approach to meet the Data Quality Objectives. Olson staff have OSHA HAZWOPER 40-hour, CFR 1910.120 training (with annual refresher), and MSHA 24-hour health and safety training. We are skilled at detailed Workplan preparation (e.g., FSP, SAP, DMP, and QAP), prepared results for presentations at RAB meetings, completed projects under the ROD process, and are very experienced working with municipal, state (e.g., DEQ) and Federal agency (i.e., EPA and USFWS) regulators, as well as commercial environmental professionals throughout the U.S.
Applications for Geophysics to Environmental Problems
Underground Storage Tanks (UST)
Abandoned drums, pipes, or concrete containers
Utilities – hazardous or otherwise
Ordnance – Unexploded Ordnance (UXO) or Munitions and Explosive of Concern (MEC)
Spills or Free Product in the shallow subsurface
Abandoned oil wells
Lateral delineation of historic landfills
Vertical imaging of landfill thickness
Abandoned and covered / buried mud pits from oil well drilling
Unknown geologic conditions (e.g., karst, faults, dipping layers)
Radiometrics
Time lapse monitoring (4D) investigation for flow movement
Abandoned Mine Lands (AML) – both coal and hard rock
Leak detection for liners
Acid Mine Drainage
