Model Development for Evaluating USDA Conservation Practices

For many years the United States Department of Agriculture (USDA), through the Natural Resources Conservation Service (NRCS), has administered conservation programs to protect million of acres of land from degradation and to enforce environmental quality. The impact, effectiveness, and efficiency of these programs have not been quantified. The USDA-NRCS has been instructed to quantify the existing environmental programs and/or design new programs to more effectively and efficiently meet the conservation goals of the U.S. Congress. Therefore, the NRCS and the USDA Agricultural Research Service (ARS) are currently leading a project to quantify the effects of the USDA conservation programs. The project, known as the Conservation Effects Assessment Project (CEAP), has two major components: (1) a National Assessment that will be conducted using NRCS data and watershed scale models developed by the ARS, and (2) the Watershed Assessment Study (WAS) which is concerned with detailed assessment of conservation programs on selected watersheds. The National Assessment will provide estimates of conservation benefits at a national scale. Two ARS models have been identified to make this assessment: SWAT (Soil Water Assessment Tool) and AnnAGNPS (ANNualized AGricultural Non-Point Source). The National Assessment approach is to provide state-of-the art modeling capability for estimating conservation effects on a regional basis. The Object Modeling System (OMS) will be used to assist the development of these regionalized models. This system is in effect a modular modeling framework containing a library of simulation modules describing specific component processes. Depending on the nature of the dominant processes, components can be assembled under the OMS into a regionalized watershed model that best reflects the critical problems of the region under consideration. This presentation will discuss in broad outlines the CEAP program and the development of the OMS framework for use in regionalized watershed model development.