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This article in SSSAJ

  1. Vol. 66 No. 5, p. 1620-1629
    Received: Jan 9, 2001

    * Corresponding author(s): tgish@hydrolab.arsusda.gov
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Evaluating Use of Ground-Penetrating Radar for Identifying Subsurface Flow Pathways

  1. T. J. Gish *a,
  2. W. P. Dulaneya,
  3. K.-J. S. Kungb,
  4. C. S. T. Daughtrya,
  5. J. A. Doolittlec and
  6. P. T. Millerd
  1. a USDA-ARS Hydrology and Remote Sensing Laboratory, Animal Natural Resources Inst., Beltsville, MD 20705
    b Univ. of Wisconsin, Madison, WI 53706
    c USDA-NRCS, Newtown Square, PA 19073
    d Advanced Geological Services, Malvern, PA 19355


Complex interactions between soil heterogeneity and soil water movement have inhibited the development of a methodology to accurately monitor subsurface water or chemical fluxes at the field-scale. A protocol is presented that identifies subsurface convergent flow pathways resulting from funnel flow which are critical for determining field-scale water and chemical fluxes. Georeferenced ground-penetrating radar (GPR) data were collected on a coarse resolution grid (25-m spacings) across 7.5 ha and a fine resolution grid (2-m spacings) across 22 0.06-ha plots. Although spherical models generally provided the best fit to experimental semivariograms of the restricting layer depth at a variety of spatial scales, the distance over which these data showed spatial dependency, that is, as reflected by semivariogram ranges, was highly dependent upon the scale of observation. Georeferenced ground-penetrating radar images of soil stratigraphy were used to create three-dimensional maps of the depth to the layer or horizon which restricts vertical water movement. Hydrologic models were used in conjunction with a geographic information system to determine potential flow pathways from topographic maps of subsurface restricting layers. A network of soil moisture probes allowed GPR-identified subsurface flow pathways to be verified. This suggests that a methodology incorporating GPR data and real-time soil moisture sensors may be used to identify subsurface flow pathways and to monitor subsurface water flow.

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Copyright © 2002. Soil Science SocietyPublished in Soil Sci. Soc. Am. J.66:1620–1629.