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Title: THE USDA-ARS LITTLE WASHITA RIVER EXPERIMENTAL WATERSHED

Author
item Van Liew, Michael
item Starks, Patrick
item Steiner, Jean
item Daniel, John

Submitted to: Interagency Conference on Research in the Watersheds
Publication Type: Proceedings
Publication Acceptance Date: 10/1/2003
Publication Date: 10/27/2003
Citation: Van Liew, M.W., Starks, P.J., Daniel, J.A., Steiner, J.L. 2003. The USDA-ARS Little Washita River Experimental Watershed. In: Proceedings of the First Interagency Conference on Research in the Watersheds, October 27-30, 2003, Benson, AZ. p. 50-55.

Interpretive Summary: A drainage area of the Washita River in Southwestern Oklahoma, known as the Little Washita River Experimental Watershed (LWREW), is unique in that over a period of four decades, it has been the focus of extensive research related to soil and water conservation. Located about 50 miles Southwest of Oklahoma City, the LWREW is one of the USDA Agricultural Research Service's (ARS) largest and best-instrumented experimental watersheds. It drains an area of 236 square miles on gently rolling hills that consists of rangeland (66%), crops (19%), forest (9%) and miscellaneous land use types (6%). The LWREW has been operated and maintained by ARS since the 1960s and provides a wealth of information that has been collected from instruments distributed across the watershed. Information has also been collected on the watershed from aircraft or orbiting satellites through a process referred to as remote sensing. A meteorological network, consisting of 42 stations, spaced about 3 miles from one another, provides 5-minute measurements of rainfall, air temperature, relative humidity, solar radiation, and soil temperature on an automatic basis. These measurements as well as wind speed, wind direction, and air pressure are also monitored at three sites by the University of Oklahoma/Oklahoma State University, which maintain a network referred to as the Oklahoma Mesonet. In addition, hourly measurements of soil moisture and soil temperature are made at 12 ARS soil heat and water measurement stations. Ten stream gages are located in the watershed, with three on the main stem of the river. Current research on the LWREW is designed to address problems related to the impacts of changes in land use and variations in climate on surface and ground water resources. Research also consists of using remote sensing techniques to monitor and predict soil water content and availability over large areas. Research from these programs is expected to promote the conservation of water resources and to help reduce uncertainties associated with the availability of water due to fluctuations in climate.

Technical Abstract: The Little Washita River Experimental Watershed (LWREW) located in the Red River Basin of the Southern Great Plains (SGP) near Chickasha, OK is one of USDA Agricultural Research Service's (ARS) largest and best-instrumented watersheds. The LWREW drains an area of 610 square kilometers and is characterized by variations in topography, soils, and land use. The watershed is located within a steep precipitation gradient of the SGP, making it ideal for conducting research on regional mass and energy fluxes at the earth's surface. The LWREW has been operated and maintained by ARS since the 1960s and provides a wealth of field and remotely sensed data. An automated meteorological network, consisting of 42 stations, spaced at 5 km intervals, provides 5-minute measurements of rainfall, air temperature, relative humidity, solar radiation, and soil temperature. These variables as well as wind speed, wind direction, and air pressure are also monitored at three of the University of Oklahoma/Oklahoma State University Mesonet sites. Hourly measurements of soil matric potential, heat flux, and soil temperature are made at 12 soil heat and water measurement stations. Ten stream gages are located in the watershed, with three on the main stem of the river. Current research on the LWREW is designed to address problems that relate to the integrated effects of agricultural land use, land management and climate variability on surface and ground water resources and the use of remote sensing techniques to monitor and predict root zone water content and availability at regional scales. Research from these programs is expected to promote the sustainable use of water resources and to help reduce the risk associated with fluctuations in climate. Current research on the LWREW also facilitates multi-stakeholder discussions for UNESCO's HELP (Hydrology for the Environment, Life and Policy) in the Red-Arkansas River Basin.