不同潮型和风况下青草沙水库取水口盐水入侵来源

Saltwater intrusion sources at the water intake of Qingcaosha reservoir in different tidal pattern and wind case

本文应用2013年12月和2014年2月青草沙水库取水口实测盐度和数值模式计算的流速流向,分析水库取水口盐水入侵的来源.2013年12月枯季在一般径流量和风况的情况下,大潮、大潮后中潮和小潮前期水库取水口盐水来源于上游的北支倒灌,小潮中后期、小潮后中潮盐水入侵来源于北港下游外海的盐水入侵.观测资料发现2014年2月长江河口盐水入侵是近几十年来发生过的最严重盐水入侵事件,导致青草沙不宜取水的时间达到23 d,对上海的安全供水造成了严重威胁.2014年2月枯季在一般径流量和持续偏北大风15 d情况下,所有4个潮型中青草沙水库取水口盐水均来自北港外海的正面入侵.

The measured salinity and numerical simulated current speed and direction in December2013 and February 2014 were used to analyze the source of saltwater intrusion at the water intake of Qingcaosha reservoir. Under the general river discharge and wind case in dry season December 2013,the saltwater sources at the water intake during spring tide,medium tide after spring tide,early neap tide came from the upstream saltwater-spill-over from the North Branch into the South Branch,whereas during late neap tide and medium tide after neap tide came from the downstream open sea,i. e.,through the saltwater intrusion in the North Channel. It was found that the saltwater intrusion in the Changjiang Estuary in February 2014 was very severe and had never been happened in recent decades,which resulted in the not suitable take water days of the reservoir reach to 23 days,and serious threat of safety water supply in Shanghai. Under the general river discharge and long continue strong northerlies lasting 15 days in February 2014,the saltwater sources at the water intake of Qingcaosha reservoir during the all four tidal patterns came from the downstream open sea saltwater intrusion through the North Channel.