The upstream lakes and dams in Oklahoma play a critical roll in the operation of the navigation system, since there is no floodwater storage allocated in the Lock and Dam Reservoirs. Each reservoir operates for their individual authorized purposes; however, in the case of flood risk management each reservoir has limitaions according to downstream conditions. Linked by their discharge to the same river system, the Arkansas main stem, the reservoirs operate not only for local conditions, but also as a part of a larger system. Integrated with other projects, these lakes help to reduce high flows and augment low flows on the Arkansas and the Mississippi Rivers.