Parts of the river itself are designated for recreational or preservational use . The Missouri National Recreational River consist of portions of the Missouri downstream from Fort Randall and Gavins Point Dams that total 98 miles ( 158 km ) . These reach exhibit islands , meanders , sandbars , underwater rocks , riffles , snags , and other once @-@ common features of the lower river that have now disappeared under reservoirs or have been destroyed by channeling . About forty @-@ five steamboat wrecks are scattered along these reaches of the river .