Rivers and the swath of land next to rivers are critically important for aquatic and riparian ecosystems and ecological processes, water resources, human infrastructure, and natural hazards. Several hydrologic and geomorphic processes—including flooding, erosion, deposition, river migration, bank failures, and landslides—create dynamic areas where water, sediment, nutrients, carbon, and pollutants are transported, sometimes gradually and sometimes catastrophically (Bierman et al., 2014). In 2019, Gartner et al. created a novel approach for delineating the area adjacent to a river that is likely to affect and be affected by river and floodplain processes, and called that area the river process corridor (RPC) (Gartner et al., 2019). They tested this delineating method in three river reaches in Northeastern U.S. and found the method to be successful at providing both an accurate assessment of potential active hazard areas and sensitive environmental areas, and that it also includes a margin of safety that many managers desire. This project proposes to apply the method to four entire sub-watersheds in the Deerfield River watershed in northwestern Massachusetts, that were delineated with a more complex method, in order to determine whether the method is truly accurate and easy to use in a region that does not have Federal Emergency Management Agency flood zones.