近40年洞庭湖澧水洪道冲淤演变分析

Research on the Fluvial Process of the Lishui Flood Channel in Recent 40 Years

基于澧水洪道实测水文资料、不同年代水下地形资料、断面测绘资料及现有相关研究成果,系统分析研究了澧水洪道及七里湖槽蓄量变化、洪道重点部位冲淤变化特征、纵断面及典型横断面冲淤演变规律等。结果表明1995年来澧水洪道平面调整不大,但河槽冲刷较明显,滩地存在淤积,洪道整体表现为冲刷。七里湖槽蓄量1995-2003年间略有减小,2003-2011年槽蓄量增长较快。随着上游水库的运用,2003年后河道深泓下切速率加快,洲滩普遍存在泥沙淤积,新河口、柳林咀河段存在较强的演变趋势,需要加强观测并采取必要的稳定河势措施。

Based on the measured hydrological data, underwater topographic data, cross-section mapping data in different years and existing research findings of the Lishui Flood Channel, this paper studies the variation of storage capacity of Lishui Flood Channel and Qili Lake Channel, the variation characteristics of erosion and deposition in key parts of flood channel, the evolution law of erosion and deposition in vertical section and typical cross-section. The results show that the level of Lishui Flood Channel has not changed much since 1995, but the riverbed fluvial scour is obvious. It also shows that the beach of the Lishui Flood Channel is the place of sediment deposition while the whole of the flood channel is scouring. With the operation of the upstream reservoir, the scouring rate of river channel has been accelerated since 2003. There is a strong trend of evolution in Xinhekou and Liulingzui reach where it is necessary to strengthen observation and take necessary measures to stabilize the river regime.