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Debris Problems in the River Environment

Fred F. M. ChangHsieh Wen Shen

出版	Department of Transportation, Federal Highway Administration, [Office of Research], Environmental Design & Control Division, 1979
URL	http://books.google.com.hk/books?id=BJjVgdxiG9cC&hl=&source=gbs_api

註釋

Debris causes hydraulic problems at highway bridges nationwide. The problems are the greatest in the Pacific Northwest and the upper and lower Mississippi River Valley. Debris hazards are local and infrequent phenomena often associated with large floods. Most bridge destruction is due to accumulation against bridge components. Debris may partially or totally block waterways and create adverse hydraulic conditions that erode pier foundations and bridge abutments and do other structural damage. Many debris problems exist in forested areas with active logging operations. Bridges on streams where stream slopes are mild or moderate, in contrast to headwater streams, are more vulnerable to debris related hazards. Debris hazards occur more frequently in unstable streams where bank erosion is active.