ARS | Publication request: WATERSHED-SCALE SENSING OF SUBSURFACE FLOW PATHWAYS AT OPE3 SITE

Submitted to: First Interagency Conference on Research in the Watersheds
Publication Type: Proceedings
Publication Acceptance Date: August 5, 2003
Publication Date: October 23, 2003
Citation: Gish, T.J., Walthall, C.L., Daughtry, C.S.T., Dulaney, W.P., McCarty, G.W. 2003. Watershed-scale sensing of subsurface flow pathways at OPE3 site. In: Proceedings of the First Interagency Conference on Research in the Watersheds, October 27-30, 2003, Benson, Arizona. p. 192-197.

Technical Abstract: The Optimizing Production inputs for Economic and Environmental Enhancement (OPE3) research program focuses on developing strategies for meeting economic crop production goals while mitigating excess chemical loss to neighboring ecosystems. The OPE3 site has four hydrologically-bounded watersheds, about 4 ha each, which feed a wooded wetland and first order stream. Among the OPE3 watershed-scale research projects seeking to meet these goals are investigations focused on methods to quantify spatial variations of water and nutrients vial characterization of subsurface flow pathways and analysis of crop response. Subsurface topography of the first continuous clay lens was determined by combining ground-penetrating radar (GPR) data with surface digital elevation maps to identify the spatial location of subsurface convergent flow pathways. Remote sensing provided information on crop nitrogen status and foliage density via spectral vegetation indices (SVI) from an airborne imaging system. Both the spectral and spatial information domains of imagery are being used to map Lai and leaf chlorophyll at high spatial resolutions (1 to 4 m pixels). These analyses provide links for mapping the impact of soil water dynamics over several growing seasons. The maturation and fusion of these technologies will permit an assessment of watershed strategies influencing water and chemical flows and their impacts on surrounding ecosystems while simultaneously assessing the effectiveness of management strategies on crop production.