Northern Prairie Wildlife Research Center
Roberts and his co-workers charted the Missouri River to assess its navigational potential from the Three Forks to the Great Falls during the summer of 1872. Roberts' journal contains some interesting natural history notes. Roberts calculated the flow of the Missouri River at the Three Forks in mid-July to be 8,533 cfs. He reported a ferryman as stating the river level was only about 8 inches above its lowest point.
Roberts, T.P. 1902. The upper Missouri River, from a reconnaissance made in 1872. Contributions to the Montana Historical Society. vol 1, 2nd ed. Independent Publishing Company, Helena, MT.