Using high resolution synthetic aperture radar for terrain mapping: Influences on hydrologic and geomorphic investigation

A high resolution digital elevation model (DEM) was constructed for the USD A-ARS Walnut Gulch Experimental Watershed located in southeast Arizona usin g interferometric synthetic aperture radar (IFSAR) processing techniques. T hree lower resolution DEMs had previously been constructed for the watershe d; a 40m photogrametrically derived surface, a combination USGS Level I and II 30m surface, and a derivative 10m surface. The IFSAR DEM, with a resolu tion of 2.5m and high vertical accuracy, is potentially a significant impro vement in terrain representation. This study investigates the differences i n topographic representation among the photo, USGS, and IFSAR DEMs and illu strates the influence they have on hydrologic and geomorphic studies. Water shed characteristics such as area, geometry, drainage network, slope, and d rainage density, derived from the DEMs, are compared. Results from these st udies demonstrate the impact of using IFSAR technology on watershed hydrolo gic and geomorphic research at a range of watershed scales.