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Applied Geophysical Research

The Office of Ground Water, Branch of Geophysics (OGW BG) conducts applied geophysical research to support studies of the Nation's water resources. Research at the Branch is focused on the development and testing of new and emerging geophysical methods to image near-surface geologic structure, measure hydraulic properties, and estimate physical properties that control hydrologic processes.

Applied research conducted by OGW BG is supported by numerous sources including the Office of Ground Water, the Toxic Substances Hydrology Program, the Ground-Water Resources Program, and cooperative relationships with other federal agencies, state agencies, and universities.

Applied research by the Office of Ground Water, Branch of Geophysics focuses on several themes:

• development and testing of surface, borehole, and water-borne geophysical data acquisition and analysis methods to image geologic structure and estimate physical properties that control fluid flow and contaminant transport;
• direct and indirect detection of contaminants;
• monitoring of hydrologic and remedial processes; and
• development of advanced geophysical acquisition and processing methods.

Current examples of some of these themes are included below. For more information, also see our recent publications or our online geophysical technology information and resources section.

In recent years, hydrologists and geophysicists have been placing an increased emphasis on the development and advancement of the field of hydrogeophysics. Professional societies such as the American Geophysical Union define hydrogeophysics as

the use of geophysical methods to estimate parameters and monitor processes important to hydrological investigations, such as those associated with water resources, contaminant transport, ecological and climate investigations.

Hydrogeophysics emphasizes a more fully integrated approach to the study and applications of hydrology and geophysics, from project planning through data collection and into data analysis and interpretation. This theme runs through much of the applied research conducted by the OGW, Branch of Geophysics, particularly in the areas of contaminant detection and geophysical monitoring.

• Detection of Contaminants
• Applied geophysics and discrete-zone monitoring at the University of Connecticut landfill study area
• Integrated, multidisciplinary"tool box" approach to development of site conceptual model:
• Use of geophysical tool box to characterize ground-water flow in fractured-rock
• Geophysical Monitoring
• Electrical resistivity tomography (ERT) monitoring:
• Saline tracer tests and salt water intrusion in porous media
• Borehole radar tomography monitoring:
• Biostimulation for remediation through vegetable oil injection in porous media
• Steam-enhanced remediation (SER) in fractured rock
• Hydrologic and remedial processes in fractured rock:
• Applied research through USGS Toxic Substances Hydrology Program
• Applied research at the University of Connecticut landfill study area
• Geostatistical Modeling of Aquifer Properties
• Assessing the resolution-dependent utility of tomograms for geostatistics

The field of geophysics is constantly evolving, with new equipment being developed and emerging applications for existing methods and systems. OGW, Branch of Geophysics uses a wide array of geophysical methods and equipment, and is actively involved in the development and testing of new and emerging geophysical data acquisition and analysis methods that can be applied to groundwater investigations. Some of our recent applied research in this area has included the following methods:

Electrical Resistivity

• Continuous resistivity profiling (CRP) in shallow-water environments for mapping saltwater/freshwater interface and sub-bottom contamination plumes
• Electrical resistance tomography (ERT) for estimation of hydraulic properties in porous media

Radar

• Borehole radar cross-hole tomography and directional reflection
• Advanced methods for cross-hole data analysis

Seismic

• Continuous seismic reflection profiling in shallow-water environments for sediment classification and mapping
• Horizontal-to-vertical ambient-noise seismic method technology demonstration and evaluation project

Hydraulic Methods

• Discrete-zone isolation to prevent cross-contamination
• Discrete-zone monitoring to determine hydraulic head, connections between transmissive zones within fractured rock, and the extent of connection between fractured rock and surficial aquifers

Natural gamma

• Spectral gamma borehole logging for litho-typing and correlating structural and geologic features across sites

Temperature Monitoring

• Fiber-Optic Distributed Temperature Sensing Technology Demonstration and Evaluation Project