民主垸溃口入垸水量计算及出险成因分析

洞庭湖区从１９９５年到１９９９年间有４年发生特大洪水，大小共计几十个堤垸溃或愉。１９９９年７月益阳民主垸溃疡后，长江不文部门组织施测了从溃口开始到堵口复堤期间长达９０多天的水位、流量、溃口地形、河订地质等资料。通过大量实测数据，结合附近基本文站网的资料，把民主垸溃决作为一次分洪溃口的试验模型，对民主垸的入出流过程、入垸总水量、垸内 作用、资水中下游河段水位降低幅度及出险成因等方面进行限分析，为资水

Calculation of water entering into Minzhu Polder through a dyke breach and analysis of breach cause

From 1995 to 1999,several catastrophic floods occurred in the Dongting lake area,and dozens of large to small-sized polder dykes were breached.After Minzhu polder dyke in Yiyang was breached in July 1999,the hydrologic departments of Changjiang Water Resources Commission carried out measurements of water level,discharge,and surveys of topography,river bed geology at the breach in a period of more than 90 days from the beginning of the dyke breach to its closure.The breaching of Minzhu polder dyke are taken as an experimental model of breaching the dyke for flood diversion in this paper.The inflow and outflow of the polder,total water volume entering the polder,effect of segragating tykes in the polder,drawdown range of water level in the middle and lower reaches of Zishui River and causes of the dyke failure etc.are analyzed by using numerous data measured at the breach and historical materials of the nearby hydrometric basic station.This calculation and analysis provide reliable results for the planning and regulation of Zishui River and for flood diversion routing of Yangtze River.