Stream Channel Stability. Appendix E. Geomorphic Controls of Channel Stability,
SOIL CONSERVATION SERVICE OXFORD MS SEDIMENTATION LAB
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This process-oriented study was organized to investigate three complementary aspects of channel stability including a the nature of channel failure processes b the influences of valley-fill depositional units on these processes and c the properties and distributions of the valley-fill units. The study included the near-surface geologic investigation, investigation of the late-Quaternary valley-fill deposits, and channel morphometric investigations. The properties and distributions of the valley-fill units directly and indirectly influence the nature of channel failure processes. Although gravity-induced failure is the most frequent form of present-day bank instability, the type of gravity failure is dependent upon the properties of the valley-fill units. Both depositional and weathering properties influence the type of failure. The valley-fill units indirectly influence bank stability through their control of groundwater movement and the development of unusually large seepage forces at point-locations along the channels. Bed instability has primarily resulted from upstream migration of knickpoints and the rate of knickpoint migration has been affected by valley-fill unit controls. Present drainage systems in the study area are immature channel morphometry has not adjusted at this time to the new flow regime resultant from cultural and natural changes.
- Geology, Geochemistry and Mineralogy
- Hydrology, Limnology and Potamology