Use of ground-penetrating radar on upland Coastal Plain soils

ABSTRACT: A study was conducted to determine the effectiveness of ground-penetrating radar (GPR) for detecting soil horizons and geologic layers with different characteristics, for determining their thicknesses, and for measuring depth to the water table in upland Coastal Plain soils. Common upland soils of the Georgia Coastal Plain were grouped by texture and presence of plinthite into the categories clayey, loamy nonplinthic, loamy plinthic, and sandy. GPR was tested on soil series within each group, and its effectiveness on upland Coastal Plain soils was found to vary primarily with soil texture. GPR provided clear delineation of underground features on the sandy soils and also delineated layers with different moisture and texture on certain loamy plinthic and nonplinthic soils. Use of the technique by the Southeast Watershed Research Laboratory has shown GPR to be useful for research planning, particularly for groundwater research on deep sandy soils because it provides a continuous record of underground features and is nondestructive. Calculation of percentage of the Georgia Coastal Plain landscape for which GPR may be used effectively showed that on at least 27% of the landscape GRP can be an important site investigative tool for differentiating and determining the thicknesses of soil horizons or geologic layers or for determining the depth to the water table.