Foster Reservoir, located near Sweet Home, is part of the Corps’ Willamette Valley System of 13 dams and reservoirs, which span from Detroit to Cottage Grove and were built between 1940 and 1969 primarily for flood risk management. The Corps is currently updating its long-term plan, referred to as a master plan, for managing recreational, natural, and cultural resources at Foster and Green Peter Reservoir, located just upstream of Foster.