枯季三峡库区泄流对缓解长江口盐水入侵的数值模拟研究

Numerical Simulation Study on Mitigation of Saltwater Intrusion in Changjiang Estuary During the Flood Season in the Three Gorges Reservoir Area

为研究枯季三峡库区泄流后对长江河口咸潮入侵的影响,利用三维数值模式ECOM-si分别模拟了枯季1、2月份径流量为大通站实测多年平均状况下和三峡库区受上游水库群调蓄后保持天然入库量的情况下泄流后长江河口的盐水入侵特征,模拟结果表明:(1)三峡库区泄流对缓解长江口咸潮入侵有一定的作用,表现在径流量增加,咸潮入侵变弱;(2)上游放水后在大潮涨憩期间对北支盐水入侵影响不大,但使得南支北港和南港部分地区在大潮涨憩期间出现了淡水;(3)从等盐度线垂直分布方向上看,泄流后大小潮涨憩时刻的等盐度线较之前相比都向海洋方向移动;(4)从取水时间上来看,三个水库在泄流后不宜取水天数和取水时间都发生了变化,不宜取水时间分别缩短了1~2d,且青草沙水库盐度的日变化幅度也有所缩小。

In order to study the influence of the discharge of the Three Gorges Reservoir on the saltwater intrusion in the Yangtze estuary after the drainage in the dry season, the three- dimensional numerical model ECOM-si was used to simulate the runoff in January and February in the dry season respectively.The results showed that： （1）The discharge from the Three Gorges Reservoir Area plays a certain role in alleviating the saltwater intrusion in ＂the Yangtze Estuary, showing in the increase of flow rate and the decrease of saltwater intrusion. （2） The upper and lower water diversions have little effect on the salt water intrusion in the northern branch during the spring tide, while the northern part of Nanzhibei North Port and some parts of South Port appeared fresh water during the spring tide- （3） In the vertical direction of the salinity line, the salinity line of the tidal wave after the discharge of the discharge is moving in the direction of the sea. （4）From the point of water in time, three days after discharge is unfavorable for water reservoir and water time has changed, not for water, respectively, to shorten the time of 1 to 2 days.The diurnal variation of the grass and sand reservoir salinity range is narrow.