The Wind Erosion Prediction System (WEPS) is a process-based, daily time-step, computer model that predicts soil erosion via simulation of the fundamental processes controlling wind erosion. WEPS can calculate soil movement, estimate plant damage, and predict PM-10 emissions when wind speeds exceed the erosion threshold. It also can provide the user with spatial information regarding soil flux, deposition, and loss from specific regions of a field over time. WEPS is intended for conservation planning, assessing wind erosion for USDA-NRCS's National Resources Inventory (NRI), and aiding the development of regional and national policy. WEPS modular design is amenable to incorporation of new features. Thus, WEPS will also be used for estimating long-term soil productivity, determining physical damage to crops, depositional loading of lakes and streams as well as estimate visibility reductions near airports and highways. WEPS will also aid in calculating both on-site and off-site economic costs of erosion and assess impacts of management strategies on public lands when used in conjunction with other models.