2011 Annual Report 1a.Objectives (from AD-416) The objectives of this cooperative research project are to develop new methods and technologies to improve the measurement and modeling of erosion and sediment yield at a range of scales, with an emphasis on the development of the Rangeland Hydrology and Erosion Model (RHEM) and application to the Conservation Effects Assessment Project (CEAP). Develop methods and techniques for quantifying natural and anthropogenic induced ephemeral-channel runoff and subsequent recharge in cooperation with U.S. Geological Survey Tucson Science Center under current and projected climate scenarios Develop methods and techniques to quantify and predict water budgets of riparian ecosystems under current and projected climate scenarios through direct measurements of evaporation and plant transpiration and predict water savings by removal of invasive mesquite vegetation. Develop methods and techniques to explicitly quantify the spatial and temporal distribution of vegetation, land use, and infiltration reduction using remotely sensed methods to improve prediction of basin scale semi-arid water budget components. 1b.Approach (from AD-416) The RHEM model will be tested, and parameter estimation procedures will be developed. A web-based interface will be constructed. The model will be linked to NRCS databases included the National Resource Inventory (NRI), and methods will be developed to assess the impact of conservation practices on natural resources, and soil erosion in particular. Relative accuracy of the models will be compared and documented, and models will be evaluated in terms of the type of information that each model is able to provide. Documents SCA with U of AZ. Replacing 5342-12660-004-02S 407119 (3/08). 3.Progress Report This project involves developing field and watershed scale models of runoff and erosion in rangeland environments. The Rangeland Hydrology and Erosion Model (RHEM) has been advanced with improved parameter estimation routines and model interfaces. RHEM has also been incorporated into the AGWA system via inclusion in KINEROS routines. Addition field data continues to be collected with the rainfall simulator to enable parameterization in more environments. RHEM was applied across rangelands of the western United States to assess current state of rangelands and effects of conservation practices for purposes of USDA reporting in conjunction with the Resources Conservation Act. The lead scientist and/or ARS representatives meet with University collaborators and employees on at least a monthly basis to assess progress.