Missouri River Basin Overveiw

Science Center Objects

Learn About the Missouri River Basin


The Missouri River is the largest river in North Dakota and accounts for 80 percent of the total mean streamflow in the State. The Missouri River Basin is comprised of seven major subbasins and drains about 34,000 square miles or about 48 percent of the State's total area.

Of the original 390 Missouri River miles in North Dakota, about 80 miles remain free-flowing. These free-flowing river miles are located in the reach just below Garrison Dam and upstream from Lake Oahe (formed by a Oahe Dam located in South Dakota). Garrison Dam, about 70 miles north of Bismarck, was built in 1953 as part of a system of dams and reservoirs located on the Missouri River in Montana, North Dakota, and South Dakota. The U.S. Army Corps of Engineers built the dams, in part, to control flooding on the Missouri River. Before the construction of Garrison Dam, the maximum peak streamflow measured at Bismarck was 500,000 cubic feet per second on April 6, 1952. For 1954-2000, the annual mean flow at Bismarck was 23,170 cubic feet per second.

Helpful Links