Joe Cain Pushing a Ground Penetrating Radar (GPR) cart at an urban site to locate subsurface pipes.
The greatest risks and unknowns at redevelopment sites are typically within the subsurface, this can pose significant challenges and require broad site assessments to be contracted by stakeholders. Be it a brownfield site, historic gas station, military
base, industrial area, or Superfund site, these properties can contain contamination
and hidden subsurface infrastructure from previous commercial or industrial usage.
The majority of these sites carry great uncertainty due to lack of information and
documentation on their historical use.
Geophysical Operations CART or “G.O.CART”
Geophysical instruments coupled with a GPS navigation system and controlled by a Pocket PC (PDA) are towed by an all-terrain vehicle (ATV) during a site clearance survey.
Geophysical tools and techniques are very cost-effective and most practical
approach to assess these types of sites and pinpoint problems prior to the traditional
intrusive and per-point site investigation methods. Geophysics techniques are easily
applied to sites ranging from a single acre to 100’s of acres in size, remote sites to
downtown urban areas, paved or dirt ground, and site clearance data can often be
turned around rapidly.
Large Area Site Clearance Example
Results from an electromagnetic survey across an Air Force Base site to map potential historic foundations, utility lines, and areas of disturbed ground – hydrogeophysics
In the site clearance example above are the results of an electromagnetic survey
across an Air Force Base site to map potential historic foundations, utility lines, and
areas of disturbed ground. This 12-acre site was surveyed over two days with the
electromagnetic method providing information on both the ground conductivity and
metallic objects in the subsurface.
UST Site Clearance Example
Survey for the location and delineation of USTs, and UST footprints for tank removal
Hydrogeophysics has over 25 years of experience locating and identifying USTs at numerous sites across the country. We employ a range of geophysical techniques, including ground penetrating radar, electromagnetic induction, and magnetics, to custom design surveys based on available information on tank design and site conditions. Survey design can range from simple determination of the number and location of USTs, to accurate delineation of UST footprints and depths to allow tank removal with minimal disturbance to the surroundings or assist with positioning for direct sampling for leak detection.