USDA - Natural Resources Conservation Service
Ground Penetrating Radar Program

Guide to Interpreting Radar Profiles | Using GPR to Map Peat Deposits | GPR Surveys on Cranberry Beds
Instructions on how to download GPS data and create contour maps


Video: Using Ground-Penetrating Radar for Soil Survey

SIR System -3 GPR unit with a 300 MHz antenna (photo courtesy of GSSI The use of trade names in this article does not constitute endorsement by the USDA)

NRCS GPR Program
The United States Department of Agriculture, Natural Resources Conservation Service (USDA-NRCS) has been using ground-penetrating radar (GPR) technology to study soil subsurface features since 1979. GPR is a broad band, impulse radar system that has been specifically designed to penetrate earthen materials. The GPR unit provides a continuous real-time profile of subsurface features in soil and geologic deposits.


GPR Profile of an area of Bridgehampton and Enfield Soils. The GPR profile (right) shows the eolian/outwash interface and stratification in the outwash deposits. Photo (left) is a profile of and Enfield soil series, the eolian/outwash contact is at 50 to 55 cm.

How Does GPR Work?
The radar transmits high frequency, short duration pulses of energy into the ground from a coupled antenna. Transient electromagnetic waves are reflected, refracted, and diffracted in the subsurface by changes in electrical conductivity and dielectric properties. Travel times of reflected, refracted and diffracted waves are analyzed to give depths, geometry and material type information. The energy returning to the antenna is processed within the control unit and displayed on graphic paper.

GPR Advantages GPR Limitations
Hi resolution, vertically and laterally. Site specific applications.
Rapid. Generally, shallow depth of observation (1)
Cost effective.  
Generally, near real time interpretation.  
Numerous areas of application.  
Non destructive.  

(1) Radar depth of observation; decreases as frequency (antenna) increases, decreases as water content increases, decreases as clay/salt content increases, decreases as scattering increases, increases as transmitter power increases.

NRCS Uses of GPR

 

Investigating the variability of soil properties. Mapping peat thickness and volume.
Mapping geologic deposits. Sedimentation surveys.
Locating buried objects. Engineering application.
Hydrologic Investigations. Soil survey investigations.
Locating contamination plumes. Cultural resources/Archeological investigations.

Click Here for A Guide on Interpreting Radar Profiles

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GPR Links

Ground Penetrating Suitability Maps for the U.S.
Geophysical Survey Systems Inc.
Ground Penetrating Radar from US Radar
Ground Penetrating Radar Services
GRORADAR Ground Penetrating Radar Gary R. Olhoeft
http://www.penetradar.com/
http://www.archeologymapping.com/index.htm
http://www.geomodel.com/
http://www.ka.shuttle.de/software/index.html Sandmeier scientific software
IDS Georadar Division -
Mala Geoscience
Sensors and Software  
GPR Data.com

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