Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: April 30, 2003
Publication Date: November 4, 2003
Citation: Gish, T.J., Daughtry, C.S., Walthall, C.L., McCarty, G.W., Angier, J. 2003. Using subsurface stratigraphy to determine subsurface water flow pathways [CD-ROM]. Crop Science Society of America, Soil Science Society of America. Denver, Colorado: Agronomy Society of America. Technical Abstract: Complex interactions between soil heterogeneity and soil water movement have inhibited the development of a methodology to accurately monitor subsurface water fluxes at the field-scale. A protocol is presented that identifies subsurface convergent water flow pathways resulting from funnel flow which are critical for determining field-scale water fluxes. To identify soil layers that could restrict vertical water movement georeferenced ground-penetrating radar (GPR) data were collected on a coarse resolution grid (25 m spacings) over the entire 25 ha site as well as 44 (0.06 ha plots) fine resolution grids at 2 m spacings. The subsurface topography influencing water flow was determined by subtracting the depth of the restricting layer from a digital elevation map. Hydrologic models within a geographic information system were used to determine the spatial location of the subsurface convergent flow pathways. Independent data sets including real-time soil moisture monitoring, remotely sensed imagery, yield data, and location of upwelling zones in neighboring riparian wetland all support the location of the GPR- identified flow pathways. These findings suggests that a methodology incorporating GPR data may be used to identify subsurface flow pathways and to monitor subsurface water flow in sandy loam soils.