Submitted to: Water Resources Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/18/2007
Publication Date: 5/6/2008
Citation: Renard, K.G., Nichols, M.H., Woolhiser, D.A., Osborn, H.B. 2008. A brief background on the U.S. Department of Agriculture Agricultural Research Service Walnut Gulch Experimental Watershed. Water Resources Research. Vol. 44, W05S02, doi:10.1029/2006WR005691. Interpretive Summary: Watershed research is important for understating rainfall patterns and their relation to runoff that carries sediment to downstream points. In the southwestern US, these processes are difficult to measure. Early attempts to collect data were impeded by limitations of measurement instruments that were developed for more humid areas. Field measurements are critical for understanding watershed processes. Characterizing these processes requires long term data records. This manuscript describes the evolution of watershed research in non-forested regions of the southwestern US, with a focus on semiarid rangelands. Instrumented watersheds in Arizona and New Mexico are described. The development of specialized supercritical runoff measuring flume, and the limitations of other runoff measuring methods are described. Watershed data have been used to develop natural resource models that are important tools for land management decision making. This manuscript provides an historic perspective on ARS watershed research in the southwestern US.
Technical Abstract: Watershed research is critical for quantifying the unique characteristics of hydrologic processes worldwide and especially in semiarid regions. In 1953, the United States Department of Agriculture established the Walnut Gulch Experimental Watershed (WGEW) near Tombstone, Arizona, to conduct hydrologic and erosion research. This manuscript (1) provides a historical context summarizing the evolution of the Southwest Watershed Research Center research program, (2) describes significant contributions to instrumentation development and contributions to science, and (3) describes the current WGEW data collection program in the context of contemporary research questions. The development of specialized flumes for streamflow measurement and the establishment of the core monitoring networks are described. WGEW data have been used to quantify semiarid rainfall, runoff, infiltration, and transmission losses; to develop and validate simulation models; and to support broader, regional, basin-scale research. Currently, rainfall, runoff, sediment, meteorology, and flux data collection continue at the WGEW, but the monitoring network has been expanded, and data use has evolved to support several multiple government agencies, universities, and international research programs.