A brief background on the U.S. Department of Agriculture Agricultural Research Service Walnut Gulch Experimental Watershed

Abstract

[1] 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.

A channel transmission losses model for different dryland rivers

“…Based on previous publications (e.g. Renard, 1970;Goodrich et al, 2004; Renard et al, 2008;Stone et al, 2008;Emmerich, 2008;Osterkamp, 2008), we assumed that streamflow infiltrates into an sandy alluvium with enough depth such that it never becomes completely saturated during a streamflow event, because depth to groundwater within the WGEW ranges from ∼50 m at the lower end to ∼145 m in the central portion of the watershed (Goodrich et al, 2004; also see Spangler, 1969). Hydrological data and geo-information were made available at http://www.tucson.ars.ag.gov/dap/.…”

“…Secondly, we apply it to an ephemeral small 1.5 km channel reach in the Walnut Gulch Experimental Watershed (WGEW), Arizona, USA, which is well-known for its long-term database of semi-arid hydrology and studies on channel transmission losses (e.g. Renard, 1970;Renard et al, 2008;Stone et al, 2008). The MJR is a losing/gaining (mostly losing) river and hydraulically connected to the groundwater system; the small reach in the WGEW on the other hand is a losing stream and hydraulically disconnected to the groundwater system.…”

An experiment to gauge an ungauged catchment: rapid data assessment and eco-hydrological modelling in a data-scarce rural catchment

“…Unlike other prominent semi-arid study areas, such as Walnut Gulch (Renard et al 2008) and the Southern Pyrenees (Mueller et al 2009), the monsoon climate here is not dominated by convective thunderstorm events but by mainly south-north propagating bands of monsoon bursts (Keshavamurty and Rao 1992). This station provides daily records of temperature (min/max), relative humidity, precipitation, soil temperature, wind speed and direction, and pan evaporation.…”

Sediment database, Walnut Gulch Experimental Watershed, Arizona, United States

“…Sediment data collection in dryland ephemeral channels is notoriously difficult, and early efforts to measure sediment were hindered by inadequate measurement technologies. Most of the measurement methods and instruments available in 1953 when the WGEW was initiated were based on designs for sampling perennial flow [Renard et al, 2008]. Typical monsoon thunderstorm generated flows in dryland regions are characterized by high velocities, short durations, and heavy and coarse sediment loads.…”