The U.S. Army Corps of Engineers built many of the dams and bank control structures that now control Missouri River hydrology and geomorphology. Operations of these projects, in conjunction with projects built by other entities, provide many benefits, including moderation of flood flows that allow human activity in once flood-prone areas, reliable supplies of hydroelectric power and water supply for rural and urban areas, a reliable commercial navigation channel, and extensive water-based recreation opportunities. Recent attention to the status of, and protection for, three endangered species has focused attention on a need to better understand the river’s altered sedimentary processes and how these processes might be best managed in the interests of species recovery. Meanwhile, changes to sedimentary processes and river geomorphology threaten some benefits currently enjoyed by basin residents and water-related and other infrastructure along the river, and have been associated with the loss of wetlands along the Gulf coast.
In response to a request from the Corps of Engineers, the National Academies convened a committee to address seven questions related to Missouri River sediment. The topics covered by the questions ranged from a general overview of past and present sediment processes to how current habitat construction projects and other sediment management alternatives might support species recovery and affect local water quality, as well as land-building processes and water quality in the Gulf of Mexico. The committee thoroughly considered each question in its deliberations and spent a good deal of time discussing its consensus responses to them. Beyond specific findings and recommendations, two cross-cutting themes are reflected throughout this report.