Environmental policy has been explicitly expanded to consider nonpoint or dispersed sources of water pollutants. This study utilizes a national agricultural model to evaluate hypothetical policies of sediment control viewing the problem as primarily a national problem of agricultural land use. A sediment sector is added to the basic Center for Agricultural and Rural Development‐National Water Assessment model in order to test the impacts of sediment control policies on the agricultural production system. The primary function of this paper is to present the formulation of this model and a short summary analysis of some results. Specifically, costs of alternative control policies are analyzed. These costs are defined as the additional costs to agriculture of several alternative sediment control policie