ABSTRACT
The Walnut Gulch Experimental Watershed of the United States Department of Agriculture—Agricultural Research Service was established in 1953 with the broad objectives to (1) determine the effects of conservation projects on water yield and sediment movement and (2) quantify flood runoff from semi-arid rangeland watersheds. The 150 km2 watershed was instrumented with rain gauges and runoff-measuring flumes arranged in a pattern of nested subwatersheds. Data collected during the past 50 years have been analyzed to characterize precipitation in regions dominated by convective thunderstorms and to study and model subsequent flood wave movement, transmission losses, and water yield from complex watersheds. The effects of topography and various soil, vegetation, and surface cover complexes on water and sediment movements have been studied at spatial scales ranging from plots to watersheds. The initial research objectives have expanded to include remote sensing, nutrient cycling, and development of decision support systems. The comprehensive database has been used to characterize baseline conditions and variability inherent in semi-arid rainfall and runoff. The data have also been used to develop rainfall, runoff, and erosion prediction technologies. This 268chapter focuses on hydrologic and erosion research and includes a description of instrumentation and monitoring sites, a description of major research findings, and a summary of lessons learned from measurement and field experiences associated with both long-term and short-term projects.
