ABSTRACT
The earth’s surface is organized into an integrated system of watersheds drained by rivers that function to transport water and sediment. In addition to their role in removing runoff and sediment, rivers perform important ecological functions, represent valuable habitat to aquatic flora and fauna, are laterally connected with riparian ecosystems, and represent a longitudinal corridor between terrestrial and marine settings. Since the beginning of civilization, humans have depended on rivers as resources for food and water, irrigation, and transportation. Humans have compromised the ecological functioning of many rivers because of exploitation related to irrigation, commerce and navigation, and flood control.[1,2] Changes to river channels frequently occur because of modifications to the physical controls on river channels, sediment, and streamflow. Modification to the streamflow and sediment regime occurs indirectly because of land degradation or dams within the upper basin, or by direct engineering modifications to the main-stem channel. Changes in these physical controls have significant implications to the morphology, behavior, and ecological viability of rivers and are likely to be somewhat unique to each river basin. Nevertheless, to understand the magnitude, timescale, and character of river response, it is essential to understand the fundamental processes controlling river channel morphology.
