长江向洞庭湖分水演变规律研究

Runoff from Yangtze River into Dongting Lake though four inlets

长江自松滋口、太平口、藕池口、调弦口四口向洞庭湖分水,对洞庭湖防洪、水资源与生态环境有重要意义。本文利用三口五站的水文资料分析了包括分流比、断流天数、年内过程的变化趋势,利用水沙模型模拟结果分析了规划水平年分水量的变化趋势,并分析了三峡工程对分流比的影响。结果表明,受下游裁弯、干流水库的影响,长江向洞庭湖分水比例由50年代的30%下降到2000年以后的不足12%,断流天数不断增加,秋冬季节水量不断减少。未来水平年分水比例将进一步减少,三峡工程使这一趋势更为显著,枯水季节的水资源短缺将更为严峻。

Runoff from Yangtze River to the Dongting Lake though four inlets,Songzi,Taiping,Ouchi and Tiaoxian,is important to flood control,water resources and environment protection.This paper analyzes the observation data since 1950s,discusses the variation trends of diversion ratio,no-flow days and seasonal distribution of this runoff,predicts these trends with a flow-sediment model,and evaluates the impact of Three Gorges project.During the past five decades,the diversion ratio decreased from about 30% in 1950s to below 12% after 2000,the number of no-flow days increased,and the runoff decreased more significantly in dry season.In the future,the diversion ratio would decline further and the Three Gorges project would strengthen this trend.