,An extensive precipitation database at the 149 km2 Walnut Gulch Experimental Watershed (WGEW) has been developed over the past 53 years with the first records starting in August 1953 and continuing to the present. The WGEW is a tributary of the San Pedro River, surrounds the town of Tombstone in southeastern Arizona, and has a drainage area of approximately 149 km2. Elevation of the watershed ranges from 1220 m to 1950 m above mean sea level (MSL). Average annual precipitation for the period of 1956-2005, as measured with six gauges, is roughly 312 mm, with approximately 60% falling during the summer monsoon. Precipitation consists almost solely of rainfall with relatively rare instances of hail and snowfall. From a historical high of 95 rain gauges, a current network of 88 gauges is operational. This constitutes one of the densest rain gauge networks in the world (0.6 gauges/km2) for watersheds greater than 10 km2. Through 1999, the network consisted of analog recording weighing rain gauges. In 2000, a newly designed digital gauge with telemetry was placed adjacent (1 m) to the analog gauges. Both the analog and digital networks of gauges were in operation from 2000 to 2005 to enable a comparative analysis of the two systems. The analog data were digitized from paper charts and were stored in breakpoint format. The digital data consist of rainfall depths at 1-min intervals during periods of rainfall.,

Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support for this data set may be limited.This data set contains several parameters measured in the Walnut Gulch Experimental Watershed for the Soil Moisture Experiment 2004 (SMEX04).

,The site is located on the USDA-ARS's Reynolds Creek Experimental Watershed. It is dominated by Wyoming big sagebrush on land managed by USDI Bureau of Land Management.,

,The Walnut Gulch Experimental Watershed (WGEW) sediment collection program, established in 1953, provides event-based data for semiarid rangeland erosion, sediment transport, and yield research. Sediment loads carried through the channel network on the WGEW are high, but are typical of semiarid rangelands, and are influenced by soils, geologic parent material, and geomorphology. Typical monsoon thunderstorm generated flows in dryland regions are characterized by high velocities, short durations, and heavy and coarse sediment loads. Sediment is measured in conjunction with discharge measurements [Stone et al., 2008] that are integral to converting sample values to runoff event-based values. Sampling initiated in the 1960s was done with point intake pump samplers. The single point sampler intake tubes were later replaced with tubes that rise in response to flow and are perforated to collect depth integrated samples. Sampling with each of these systems is limited to suspended sediment smaller than the 0.635 cm diameter of the intake slots. Pump samplers are in use at the outlet of small watersheds where overland flow is the dominant hydrologic driver of sediment transport, and particles are small. As watershed size increases on the WGEW, in general, the channel network can dominate sediment delivery processes as it evolves to carry an increasingly coarse, and vertically sorted, sediment load. A traversing slot sediment sampler was designed in response to limitations of alternative sampling methods such as the pump sampler. The data collection network was expanded in 2002 and pit traps were added below the overfall at flumes 63.103 and 63.104. Analysis of these data, and efforts to process and make available the historic data, are ongoing.,

,The meteorological data and Bowen ratio energy balance systems (BREB) (Model 023/CO2 Campbell Scientific Inc., Logan, Utah, USA) data are used to calculate carbon dioxide and evapotranspiration (ET) fluxes at Lucky Hills. The stored Bowen ration instrument data from the measurement site were transmitted by radio daily to our research station in Tombstone, AZ. From there, they were transferred through an Internet connection to Tucson, AZ. The data were then divided into 5-day increments and inserted into a Quattro1 Pro spreadsheet file which had all the formulations to calculate flux of soil heat, latent heat, sensible heat, evapotranspiration rates (ET), and CO2 rates on the 20-min time step of the data. All instrument and calculated data were graphed in the spreadsheet file and thoroughly reviewed for any instrument problems or data stream collection issues. The shrub site is known as Lucky Hills, elevation 1372 m. The soil at this site is coarse-loamy, mixed, thermic Ustochreptic Calciorthids) with 3 to 8% slopes [NRCS Soil Survey, 2003]. The surface A horizon (0-6 cm) contains 650 g kg1 sand, 290 g kg1 silt, and 60 g kg1 clay with 290 g kg1 coarse fragments >2 mm, 8 g kg1 organic carbon, and 21 g kg1 inorganic carbon. Vegetation is dominated by creosotebush (Larrea tridentata (D.C.) Cov.), whitethorn Acacia (Acacia constricta Benth. (Fabaceae)), and tarbush (Flourensia cernua D.C. (Asteraceae)). Vegetation canopy height maintained an almost constant 1 m height. Carbon dioxide and water fluxes are important components of watershed function. In order to study carbon dioxide and water flux as they exist over the Walnut Gulch Experimental Watershed (WGEW), two sites were selected on the basis of their ecosystem composition, one site being dominated by shrubs and the other a grass dominated plant community. Lucky Hills is the shrub site. Measurements were made from 1997 through the present at the two sites.,

,Atmospheric carbon dioxide and moisture concentrations were measured with an infrared gas analyzer (IRGA) (LI-6262, LI-COR, Inc. Lincoln, Nebraska, USA). Measurements were made from 1997 through the present at the Kendall site. The meteorological data and Bowen ratio energy balance systems (BREB) (Model 023/CO2 Campbell Scientific Inc., Logan, Utah, USA) data are used to calculate carbon dioxide and evapotranspiration (ET) fluxes. The stored Bowen ration instrument data from the measurement site were transmitted by radio daily to our research station in Tombstone, AZ. From there, they were transferred through an Internet connection to Tucson, AZ. The data were then divided into 5-day increments and inserted into a Quattro1 Pro spreadsheet file which had all the formulations to calculate flux of soil heat, latent heat, sensible heat, evapotranspiration rates (ET), and CO2 rates on the 20-min time step of the data. All instrument and calculated data were graphed in the spreadsheet file and thoroughly reviewed for any instrument problems or data stream collection issues. Carbon dioxide and water fluxes are important components of watershed function. In order to study carbon dioxide and water flux as they exist over the Walnut Gulch Experimental Watershed (WGEW), two sites were selected on the basis of their ecosystem composition, one site being dominated by shrubs and the other a grass dominated plant community. The grass site is identified as Kendall (109560800W, 314401000N; elevation; 1526 m). The soils at the Kendall site are a complex of Stronghold (coarse-loamy, mixed, thermic Ustollic Calciorthids), Elgin (fine, mixed, thermic, Ustollic Paleargids), and McAllister (fine-loamy, mixed, thermic, Ustollic Haplargids) soils, with Stronghold the dominant soil [NRCS Soil Survey, 2003]. Slopes range from 4 to 9%. The Stronghold surface A horizon (0-3 cm) contains 670 g kg1 sand, 160 g kg1 silt, and 170 g kg1 clay with 790 g kg1 coarse fragments >2 mm, 11 g kg1 organic carbon, and 7 g kg1 inorganic carbon. Vegetation is dominated by herbaceous plants, predominately black grama (Bouteloua eriopoda (Torr.) Torr.), sideoats grama (Bouteloua curtipendula (Michx.) Torr.), three-awn (Aristida sp.) and cane beardgrass (Bothriochloa barbinodis (Lag.) Herter). Vegetation canopy height at the grass site ranged from 0.4 to 0.7 m during the growing season.,

,The Southwest Watershed Research Center (SWRC) operates the Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona as an outdoor laboratory for studying semiarid rangeland hydrologic, ecosystem, climate, and erosion processes.,,

,Weather, snow, stream, topographic, and vegetation data are presented from the South Mountain Experimental Catchments from water years 2007-2013 (10-1-2007 to 9-30-2013). The data provide detailed information on the weather and hydrologic response for four highly instrumented catchments in the late stages of woodland encroachment. Hourly data from six meteorologic stations and four weirs have been carefully processed and quality checked, are serially complete, and ideal for hydrologic, ecosystem, and biogeochemical modeling. Topographic and vegetation data, as well as stream and drainage area delineations are Lidar-derived. This study site was established in 2007 as a collaborative, long-term research laboratory to address the impacts of western juniper (Juniperus occidentalis Hook) encroachment and treatments in the interior Great Basin region of the western USA.,For more information about this dataset, contact: Patrick R. Kormos: patrick.kormos@ars.usda.gov Danny G. Marks: ars.danny@gmail.com,