水科学进展2016，Vol.27Issue(1)：1-10,10.DOI:10.14042/j.cnki.32.1309.2016.01.001
分汊河流江心洲洲头冲淤概化模型
A conceptual model of deposition and erosion of mid-channel bar head zone in anabranching river
摘要
Abstract
Head zone of mid-channel bar is a dynamic shoal of water-sediment diversion and alternative erosion-depo-sition in anabranching river. Erosion-deposition process in bar head relates to water-sediment supply and local topo-graphic condition. Through the geometric generalization of the mid-channel bar head (i.e. longitudinal upslope and lat-eral downslope) , a conceptual model of bedload transport on the bar head is derived using the concept of upslope fa-cilitating deposition and lateral downslope dividing sediment, meanwhile to obtain a critical discharge formula of the e-rosion-deposition transition. Along with increasing upstream discharge, the deposition rate in bar head increases first up to the maximum value and then gradually decreases, until approaching the critical discharge, and eventually occur-ring erosion. The deposition rate in the bar head is proportional to the longitudinal channel gradient and bed sediment diameter, inversely proportional to lateral gradient, upslope and downslope. If other conditions are the same, the shape of bar head is more asymmetric with smaller sediment load supply, more beneficial to the erosion. The critical discharge in the Tianxingzhou Island head of Wuhan reach in the middle Yangtze River predicted by this model is roughly in agreement with the hydrological observation. Nevertheless, the Tianxingzhou Island head still occurs to the deposition when the flood discharge surpasses the critical discharge. To this particularity, this study presents a new ex-planation that the regulation project (i.e. revetment) in the Tianxingzhou Island head plays a pivotal role on resisting the erosion and facilitating the sedimentation in the higher discharge condition.关键词
分汊河流/江心洲/淤积/冲刷/概化模型/临界流量Key words
anabranching river/mid-channel bar/deposition/erosion/conceptual model/critical discharge分类
水利科学引用本文复制引用
李志威,李艳富,王兆印,胡世雄..分汊河流江心洲洲头冲淤概化模型[J].水科学进展,2016,27(1):1-10,10.基金项目
国家自然科学基金资助项目(91547112) （91547112）
水利部公益性行业科研专项经费资助项目(201401063) The study is financially supported by the National Natural Science Foundation of China (No. 91547112) and the National Non-Profit Research Program of China (No.201401063) . （201401063）
