Winny Wang, Shanghai Daily
October 24, 2006

The third salt tide of this year is expected to hit Shanghai this afternoon, but it will last for a shorter period and bring less impact to the city’s tap water supply, compared with last tide, Shanghai Morning Post reported today. The Chenhang Reservoir near the Yangtze River estuary has stored fresh water for a week and will keep stable supply of tap water to water plants when the salt tide reaches. The chloride contained in water won’t exceed standard. The reservoir has a capacity of 8.3 million tons and can supply fresh water for five days. Water flow from the Yangtze River dropped to a record low in early October, only 12,400 cubic meters per second, but the flow began increasing in the recent two days, which can reduce the influence brought by salt tide. Normally, salt tides take place at the mouth of the Yangtze River in winter or early spring, when water flow in the river decreases, causing chloride levels to rise. But the city was stricken by the first summer salt tide on September 11 and the second one on October 9. Shanghai will begin building a huge water reservoir at the mouth of the Yangtze River by end of the year to ensure a plentiful fresh water supply during the city’s salt tide periods, which will be able to provide a daily supply of nearly 7.2 million cubic meters of fresh water.