ENVIRONMENTAL GEOPHYSICS


Geophysical techniques have many useful applications to environmental site characterization studies, including:


  • Mapping the location of underground storage tanks (USTs) and utilities
  • Identifying and delineating contaminant plumes in ground water
  • Delineating the extent of free-phase contaminant
  • Mapping the extent of buried waste in landfills and at uncontrolled dump sites
  • Development of geological/geotechnical models for understanding the
    distribution of contaminants


Geophysical techniques that D'Appolonia commonly applies to site environmental studies include:

DC Resistivity – This geophysical method is used to map electrical variations in the subsurface. It is frequently used to map contaminant plumes in ground water, to assess the extent of buried waste and to produce subsurface profiles.

Electromagnetic (EM) methods – EM methods are commonly applied to rapidly map lateral electrical contrasts in the ground (e.g., contaminant plumes in ground water) or to assess the extent of buried waste. EM methods do not provide the degree of vertical resolution obtainable using DC resistivity, but the method allows rapid mapping of lateral variations of subsurface electrical properties withoud placing electrodes in the ground.

Ground Penetrating Radar (GPR) – GPR offers the highest resolution of any geophysical method when soil conditions are favorable. Typical environmental applications that we have conducted with this technique include mapping of buried waste and locating underground storage tanks (USTs), pipelines, and other utilities.

Magnetics – We routinely conduct total field and gradiometer surveys for mapping the distribution of buried metallic waste locating underground tanks. The method can be used to map subtle variations in soil properties that could indicate areas of past excavation.

High Resolution Seismic Reflection – D'Appolonia has conducted research using this technique as a tool for ground water investigations.


EM survey being conducted in the field.



Some representative environmental projects where geophysical techniques have been applied are provided below.


EXAMPLE PROJECTS


Expedited Site Characterization Study at Contaminated Site

Expedited Site Characterization (ESC) is a concept developed at the Argonne National Laboratory and subsequently implemented to improve the effectiveness of pre-remedial environmental site characterizations. D’Appolonia participated in the first test ESC, which was managed by the DOE’s Ames Laboratory in Iowa. Our work consisted of conducting three-dimensional and common-midpoint-profile ground penetrating radar (GPR) surveys, as well as performing geophysical well logging.


Remedial Investigation/Feasibility Studies for Aviano Air Base

D'Appolonia investigated subsurface contamination and developed remedial cleanup designs for sites at the Aviano Air Base in Italy. The work included extensive use of geophysical techniques including electromagnetics (EM), DC resistivity, and ground penetrating radar (GPR).


Three-Dimensional Ground Penetrating Radar Research Project

D’Appolonia working in association with the Michigan Technological University conducted research to improve the interpretability of the ground penetrating radar geophysical method. The work was continued through an Expedited Site Characterization (ESC) contract with the Ames Laboratory at Iowa State University.


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