The X-DRAIN model is a user-friendly computer program based on the Water Erosion Prediction Project (WEPP) and is designed to estimate sediment yield from roads, landings, skid trails, and foot trails as affected by climate, soil, local topography, and transportation system characterictics. X-DRAIN can be used to determine optimum cross drain spacing for existing or planned roads, and for developing and supporting recommendations concerning road construction, reconstruction, realighment, closure, obliteration, or mitigation efforts based on sediment yield. The model estimates sediment yield produced by a given road or road system by summing sediment quantities from each unique road segment or road length between cross drains.