重大人类活动对洞庭湖四口水系洪水特性的影响分析

Impacts Analysis of Major Human Activities on Flow and Sediment Diversion from Four Outlets of Dongting Lake

依据长江干流水文站和洞庭湖四口水系(松滋、虎渡、藕池、调弦水系)各控制站实测数据,通过对比分析下荆江裁弯、葛洲坝水利枢纽和三峡水利枢纽等重大水利工程运行前后,四口水系分流分沙的变化,阐述重大人类活动对洞庭湖地区四口水系洪水特性的影响。结果表明,下荆江裁弯后四口分流分沙比明显减少,分流分沙量也呈递减趋势,四口分流分沙比的时间变化过程表现出不同特征。葛洲坝水利枢纽的运行对四口水系流量过程影响很小,拦沙作用也十分有限。三峡水利枢纽的蓄水对四口水系的分流分沙比影响较小,但分沙量大幅减少,洞庭湖湖区泥沙淤积量也大幅减少。

The paper illustrates the influence of four outlets of Dongting Lake （Songzi ,Hudu ,Ouchi ,Tiaoxian） flood characteristics by major human activities ,including the lower Jingjiang River curve cutoff ,the Gezhouba Dam and the Three Gorges Dam ,by con-trasting the changes of diversion of discharge and sediment of four outlets of Dongting Lake before and after major water conservancy projects ,based on control station and hydrometric station measured data from the four outlets of Dongting Lake and the stem stream of Yangtze River ,and the results show that after the lower Jingjiang River curve cutoff ,the rates of diversion of discharge and sedi-ment significantly reduce and the volume of diversion of discharge and sediment of four outlets of Dongting Lake also show a decrea-sing trend ,the time-varying process of the rates of diversion of discharge and sediment of four outlets of Dongting Lake exhibit dif-ferent characteristics .The Gezhouba Dam has little influence on split-flow process and sediment trapping .Impoundment of the Three Gorges Dam has little effect on the rates of diversion of discharge and sediment ,but the sub-sediment load is substantially reduced , also significantly reduced the amount of sediment deposition in Dongting Lake area .