长江河口青草沙水库盐水入侵来源

应用改进的三维数值模式ECOM-si,从模式计算的盐度和流向的变化过程、涨憩和落憩时刻盐度等值线和淡水区域的变化,分析在一般动力条件下青草沙水库取水口盐水入侵来源。计算结果表明,小潮后中潮、大潮、大潮后中潮和小潮期间北支倒灌占青草沙水库取水口表层盐水入侵比例分别为69.5%、89.3%、98.5%和99.5%,占底层盐水入侵比例分别为34.9%、88.9%、98.5%和99.5%。除了小潮后中潮期间底层盐水入侵来源主要来自下游外海(占65.1%),青草沙水库取水口表层和底层盐水入侵来源主要来自北支盐水倒灌,尤其是大潮后中潮和小潮期间几乎全部来自北支盐水倒灌。

Sources for saltwater intrusion at the water intake of Qingcaosha Reservoir in the Changjiang Estuary

Based on temporal variation of the simulated salinity and current direction,change of the isohaline and freshwater zone at flood slack and ebb slack,this study used the modified numerical 3-D model ECOM-si to analyze sources of saltwater intrusion at the water intake of Qingcaosha Reservoir under normal dynamic condition. The modeled results showed that saltwater-spill-over from the North Branch into the South Branch(SSO) accounts for 69.5%,89.3%,98.5% and 99.5% of the surface saltwater intrusion at the water intake of the Qingcaosha Reservoir during moderate tide following neap tide,spring tide,moderate tide following spring tide and neap tide,respectively,and 34.9%,88.9%,98.5%,99.5% of the bottom saltwater intrusion at the water intake of the reservoir during the same four-type tides mentioned above. Except for the bottom saltwater intrusion mainly from downstream open sea (accounts for 65.1%) during moderate tide following neap tide,the source of the saltwater intrusion at surface and bottom layer at the water intake of the reservoir is mainly from the SSO,especially during moderate tide following spring and neap tide.