ARS | Publication request: USING TERRAIN ANALYSIS TO PLAN THE PLACEMENT OF CONSERVATION PRACTICES IN A WATERSHED

Submitted to: Midwest Fish and Wildlife Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2003
Publication Date: December 10, 2003
Citation: Tomer, M.D., James, D.E., Isenhart, T.M. 2003. Using terrain analysis to plan the placement of conservation practices in a watershed [CD-ROM]. Kansas City, MO: Midwest Fish and Wildlife Conference.

Technical Abstract: Riparian buffers and constructed wetlands are two best management practices (BMPs) that can improve water quality. However, these practices are not equally effective in all locations. Our objective was to develop maps to help plan the placement of BMPs in a watershed for water quality benefits. Tipton Creek, a 49,000-acre Iowa watershed, provided a case study. Buffer-placement maps, developed from analysis of a 30-m digital elevation model, identified riparian locations with large wetness indices, where buffer vegetation could intercept sheet/rill flows from significant upslope areas. These sites were numerous, usually small (<200 m in length) and well distributed across the watershed's riparian areas. Candidate wetland sites were also mapped by interpreting maps of drainage area and slope, and by applying automated techniques to elevation data. A team of conservation professionals reviewed and discussed the maps in the field. Buffer maps highlighted riparian areas where perennial vegetation could effectively intercept runoff and/or manage seasonal wetness. The review team also located three feasible wetland sites, which were all identified by an automated mapping technique that provided twelve candidate sites meeting specific criteria for a USDA-supported program encouraging installation of constructed wetlands. The methods only required public data and should be applicable to other watersheds where good-quality DEM data are available. Results show that terrain analysis can provide hydrologic criteria to identify priority areas for implementing conservation practices, and that maps based of these analyses provide information that is consistent with human interpretation.