Evaluating Use of Ground-Penetrating Radar for Identifying Subsurface Flow Pathways
- T. J. Gish *a,
- W. P. Dulaneya,
- K.-J. S. Kungb,
- C. S. T. Daughtrya,
- J. A. Doolittlec and
- P. T. Millerd
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2002. Published in Soil Sci. Soc. Am. J.66:1620–1629.