Human interventions have altered almost all the river systems of the world. These interventions include channelization, alteration of stream courses, construction of levees, building of drainage channels, construction of dams and locks, installation of river training works, flow diversions, changes in land use, and many more. River systems respond to such changes through changes in flow, stages, gradients, or sediment supplies and through attempts to attain a new dynamic equilibrium suitable to the changed conditions. However, the time frame for obtaining a new dynamic equilibrium in response to an altered regimen ranges from a few years to decades or more. There are numerous examples of such alterations of large river basins and of the consequent responses of the rivers. In almost, all cases, the intervention is associated with a changed regimen of sediment delivery. The amount of sediment that is delivered either increases as a result of changed land use or decreases as a result of the construction of some form of sediment retention devices. Such devices may be created by an act of nature or intentionally, such as in the case of the construction of locks and dams. This paper presents three brief case studies, one each for the Kankakee, Mississippi, and Illinois River basins in the midwestern part of the United States of America. The drainage areas for these river basins at the locations where the case studies were conducted are 1920 square miles, 118,900 square miles, and 14,200 square miles, respectively. The impacts of channelization are illustrated by the case study of the Kankakee River, and the impacts of lock and dam construction for commercial navigational purposes are illustrated by the case studies of the Mississippi and the Illinois Rivers.