Changes in Channel Geometry and Channel Capacity of Alluvial Streams Below Large Impoundment Structures

摘要

Alluvial streams are known to form their own channels, and the characteristics of the channels is in a state of equilibrium with the bank material, and water and sediment discharge patterns. Construction of large impoundment structures on alluvial streams alters their water and sediment discharge patterns. Changes in channel geometry and channel capacity are therefore induced. In this study, the changes in channel geometry and channel capacity caused by large impoundment structures are examined. The theories of fluvial morphology and the theories of open channel flow are used for analyses. Hydraulically, the morphological changes of the stream channel are attributed to channel degradation and increased channel roughness. A channel degradation model is presented and applied on the Wakarusa River below Clinton Dam.