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原文传递 Methodology for Predicting Channel Migration.

题名：	Methodology for Predicting Channel Migration.
作者：	lagasse, p. f. zevenbergen, l. w. spitz, w. j. thorne, c. r.
关键词：	rates, extent, channel morphology, meanders, alluvial channels, hydrology, aerial photographs, aerial maps, channel shift, banklines
摘要：	This report documents and presents the results of a study to develop a practical methodology to predict the rate and extent of channel migration in proximity to transportation facilities. The principal product of this research was a stand-alone Handbook for predicting stream meander migration using aerial photographs and maps. The Handbook is published separately as NCHRP Report 533 and can be purchased through the TRB bookstore (trb.org/bookstore). The Handbook deals specifically with the problem of incremental channel shift and provides a methodology for predicting the rate and extent of lateral channel shifting and down valley migration of meanders. The comparison technique developed for this project consists of overlaying channel banklines traced from successive historic maps or photos. Movement of bankline position is then evaluated by measuring the change in radius and movement of the centroid of best-fit circles on the banklines to provide a quantitative estimate of migration distance, rate, and direction over time. Predictions can then be made on the potential position of the river at some point in the future. The process can be completed manually or by using computer photo editing software. In addition, a GIS-based approach was developed with ArcView extensions to streamline the measurement and analysis of bend migration data and aid in predicting channel migration. The ArcView extensions are included in CRP-CD-48, which comes with NCHRP Report 533. The report also contains an archive of the data base compiled on CRP-CD-49 to include all meander site data acquired for this study (141 meander sites containing 1,503 meander bends on 89 rivers in the U.S.). The methodology developed will enable practicing engineers to evaluate and determine bridge and other highway facility locations and sizes and ascertain the need for countermeasures considering the potential impacts of channel meander migration over the life of a bridge or highway river crossing. / Supplementary Notes: Prepared in cooperation with Ayres Associates, Ft. Collins, CO. Sponsored by American Association of State Highway and Transportation Officials, Washington, DC. and Federal Highway Administration, Washington, DC. / Availability Note: Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
总页数：	u0711；214p
报告类型：	科技报告