How Geophysics Supports Environmental Cleanup | HydroGeo Environmental

Environmental cleanup projects succeed or fail based on how well subsurface conditions are understood. At HydroGeo Environmental, we use applied geophysics to support environmental investigations by reducing uncertainty before intrusive work begins.

Our geophysical survey packages are commonly used to support Phase II Environmental Site Assessments (ESAs), remedial planning, and cleanup verification by providing site-wide subsurface context that traditional sampling alone cannot deliver.

Geophysics in Phase II Environmental Site Assessments

Phase II ESAs are designed to confirm the presence, extent, and potential migration of soil and groundwater contamination. While soil borings and monitoring wells provide high-quality data at specific locations, they represent only a small fraction of the subsurface.

Geophysical surveys help bridge those data gaps by screening large areas efficiently and identifying features that influence contaminant distribution. This allows environmental professionals to design subsurface investigations that are more targeted, safer, and more defensible.

HydroGeo’s Phase II geophysics support packages commonly include:

• Electromagnetic (EM) Surveys
  Used to screen for subsurface variability, buried debris, USTs, fill areas, utilities, and zones that may warrant focused sampling.

• Ground-Penetrating Radar (GPR)
  Used to identify shallow subsurface features such as USTs, trenches, foundations, and disturbed soil horizons that may not be visible at the surface.

Together, EM and GPR surveys support smarter boring placement, reduce the likelihood of missed subsurface features, and help avoid unnecessary drilling in low-risk areas.

Supporting Subsurface Investigation and Remedial Planning

Geophysics is most effective when used early in an environmental cleanup project. Our surveys are frequently performed to support:

• Subsurface investigation planning

• Utility and infrastructure clearance prior to drilling

• Identification of buried tanks, trenches, or debris

• Evaluation of site conditions that may influence contaminant migration

• Reduction of uncertainty before excavation or system installation

By integrating geophysical data with environmental and hydrogeologic interpretation, project teams gain a clearer understanding of site conditions before committing to costly field activities.

Alaska Environmental Site Investigation

HydroGeo Environmental recently supported an environmental investigation at a complex coastal site in Dutch Harbor, a former military installation characterized by steep terrain, heterogeneous soils and geology, and decades of historical industrial and military use.

To support site characterization and cleanup planning, our team conducted electromagnetic (EM) and ground-penetrating radar (GPR) surveys to screen subsurface conditions across the property prior to intrusive investigation. These surveys provided site-wide context that helped identify buried infrastructure, disturbed ground, and subsurface anomalies that could influence contaminant distribution and migration.

The geophysical results were used to refine soil boring locations, reduce uncertainty in subsurface interpretation, and improve confidence in overall site characterization. Importantly, the surveys identified several previously unknown contamination zones and an undocumented underground storage tank that were not evident from historical records or surface observations alone.

By integrating geophysical data early in the investigation, the project team was able to improve data coverage while controlling investigation costs, ultimately supporting more informed cleanup planning based on a clearer and more complete understanding of site conditions.

Working with Environmental Consulting Teams

HydroGeo Environmental regularly supports environmental consulting firms, remediation contractors, and engineering teams on cleanup projects across the Mid-Atlantic and nationwide.

Our geophysical survey packages are commonly used to:

• Screen sites prior to intrusive investigation

• Support placement of monitoring and recovery wells

• Identify subsurface features that affect remedial system design

• Provide additional lines of evidence during remediation and cleanup verification

This collaborative approach helps project teams reduce uncertainty, manage risk, and implement cleanup strategies more efficiently.

Reducing Risk in Environmental Cleanup Projects

Geophysics is not a replacement for sampling, but it is a powerful tool for improving subsurface understanding and supporting defensible environmental decisions.

By incorporating geophysical surveys into Phase II ESAs and remedial planning, HydroGeo helps clients collect better data, avoid unnecessary fieldwork, and move cleanup projects forward with confidence.

From environmental site assessments in the Mid-Atlantic to complex investigations in Alaska, our geophysics packages provide practical subsurface insight that supports effective environmental cleanup.