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Stream Channel Stability
E. H. Grissinger
其他書名
Appendix E : Geomorphic Controls of Channel Stability : Project Objective 5
出版USDA Sedimentation Laboratory, 1981
URLhttp://books.google.com.hk/books?id=eNA1jX3UNGkC&hl=&source=gbs_api
EBookFULL_PUBLIC_DOMAIN
註釋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.