A major new reservoir near Chongming Island at the mouth of the Yangtze will start supplying water to 18m Shanghai residents before 1 May 2010, when the Shanghai World Expo begins. Zhang Quan, director of the Shanghai Environmental Protection Bureau, said construction of the Qingcaosha reservoir dam was completed in late 2008.

"By late next year, around 70 to 80 per cent of the overall population in Shanghai will get access to the better-quality drinking water from the Yangtze River,” China Daily quoted Zhang as saying.

Qingcaosha will be able to store 435m cubic metres of water and provide more than half of the city’s water needs with an estimated daily supply of 7.2m cubic metres.
The reservoir will be the third major water source for Shanghai; one located on the upper reaches of the Huangpu River currently contributes 80 per cent of Shanghai’s water, with the rest supplied by Chenhang reservoir.

Although Shanghai has abundant water resources due to its location at the mouth of the Yangtze, it has long been suffered from poor water quality. High emission rates of ammonia and nitrogen in the upper reaches of the Huangpu River and salt tides, which mostly occur during the drier winter months, are two major problems.