USACE built, and continues to operate, six large and important dam and reservoir projects on the mainstem of the upper Missouri River. These dams, in combination with dams on the river’s tributaries, reduce the risk of downstream flooding along the Missouri and Mississippi rivers. When not operating to reduce flood impacts, this “mainstem” system of dams is managed for hydropower generation, water supply, water quality, irrigation, fish and wildlife conservation, navigation, and recreation benefits.