EFFORTS to improve the quality of surface waters in the United States have brought about a large number of state and federal regulations. Most of these regulations are directed at point sources of pollution, such as factories and municipal waste treatment plants. But now pollution from nonpoint sources is gaining the attention it deserves. These sources often account for the vast majority of waste discharges.
Sediment, sediment-related pollutants, and runoff from agricultural land, including cropland, rangeland, and forests, are the principal sources of nonpoint pollution. Soil erosion on cropland is a particularly important source of sediment and related pollutants. Because measures to reduce soil erosion typically reduce runoff also, nonpoint pollution policy has concentrated heavily on control of cropland erosion. This approach is evident in the conservation reserve provision of the 1985 farm bill.
Resources for the Future has developed a data base and modeling system that can assist in the design of nonpoint agricultural pollution control policy at the national level. The system permits simulations of alternative national policy approaches directed, if desired, at a variety of pollutants and geographical locations. In addition, the system accounts for the effects of point-source pollutants, thus permitting analyses of policies …