Geomorphic Study of Upper Mississippi River

In order to estimate the effects of removal of snags hazardous to navigation and construction of dikes, revetment, and locks and dams on the river geomorphology, the past and present geomorphic features of the Upper Mississippi River were studied. The geomorphic features studied include: the river position, river surface area, island surface area, number of islands, riverbed surface area, surface widths, water depth, side channels, and riverbed elevations. The study results indicate that natural and man-induced activities in the last 150 yr have produced subtle changes in the river geomorphology. The low dike fields narrowed the river, created new islands and chutes, and enlarged old islands. Locks and dams have widened the river and increased the number of islands in the pools. It was concluded that 50 yr from now the river scene of the Upper Mississippi River will be essentially as it is today if no major man-made changes or natural events occur.