Alluvial Fan Flooding (1996) / Chapter Skim
Currently Skimming:
Conclusions and Recommendations
Conclusions and Recommendations
Pages 133-138
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 133... ...
Hazardous flood processes can, in some cases, occur over entire alluvial fans or, as is more common, only on the active portions of a fan. Relict alluvial fans are entirely inactive Thin to identify the location of alluvial fan flooding, flooding processes need to be understood in regard to their temporal and spatial relationship to the landscape.
|
From page 134... ...
. The FEMA definition of alluvial fan flooding applies to this general concept, rather than to the complex reality of the flood processes that occur on various individual alluvial fans.
|
From page 135... ...
The Committee on Alluvial Fan Flooding proposes the following definition and supporting explanation, which are to be applied only with due consideration to all other conclusions and recommendations that are made in this report: Def nizion Alluvial fan flooding is a type of flood hazard that occurs only on alluvial fans. It is characterized by flow path uncertainty so great that this uncertainty cannot be set aside in realistic assessments of flood risk or in the reliable mitigation of the hazard.
|
From page 136... ...
The potential for erosion and deposition, the related uncertainty In flow path behavior, and the imprudence of increasing elevation by filling an area as a mitigation measure are joint and separate characteristics shared among many flood hazards on depositional environments other than alluvial fans, although not usually with the same intensity. It stands to reason that some of the same rules should be applied to this more inclusive type of flood hazard, termed uncertain pow path pooping, as applied to alluvial fan flooding.
|
From page 137... ...
Flooding on alluvial fans can only be evaluated on a site-specific basis. On-site evaluation of the flood hazard requires field investigations by specialists experienced in the scientific study of alluvial fan processes and the geomorphologic indicators of their present and past operation.
|
From page 138... ...
FEMA should set an example of effective risk communication by dealing directly with flood hazard uncertainty. Action to clarify confusion created by terminology will help transform the alluvial fan flooding concept from its current status as a vague, catch-all phrase to an administratively meaningful tool.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.