Qingcaosha, a riverbank area sandwiched between two of the city's satellite islets, will become Shanghai's new major water source, the Xinhua News Agency reported Tuesday.

Located to the north of Changxing Island, the area spanning some 70 sq km will be used for the construction of the city's third reservoir, with water sourced from the Yangtze. Construction is expected to begin soon.

Official information about the projected costs has yet to be released, although some media reports have speculated the figure will be about 16 billion yuan (US$2.2 billion).

The reservoir, which is scheduled for completion in 2010, will have a storage capacity of about 553 million cu m, with an estimated daily supply of nearly 7.2 million cu m. It will provide more than 50 percent of the city's water.

Currently, the city has two major water sources, with one located near the upper reaches of the Huangpu River, accounting for nearly 80 percent of the total supply, and the other, the Chenhang reservoir, located at the mouth of the Yangtze.

Shanghai has an abundance of water resources because of its location at the mouth of the Yangtze, but lacks quality fresh water.

The Huangpu, the primary water source for the city before the 1980s, has been seriously polluted by activities associated with the city's fast economic development. Shanghai's primary water source, therefore, has gradually moved north to the upper reaches of the Huangpu.

The United Nations named Shanghai as one of six cities globally facing severe water shortages.

Chen Jiyu, a professor at the State Key Laboratory of Estuarine and Coastal Research at East China Normal University, first raised the Yangtze River proposal in 1990.

The subsequent second reservoir, built near the mouth of the river, now contributes 20 percent of the city's total water supply. About 10 million city residents will benefit from the third reservoir, Chen said.

"The water quality of the Yangtze is far better than that of the Huangpu, which is facing increasingly serious hazards from pollution," Chen said.

"The Yangtze is an ideal alternative source for Shanghai due to its larger water supply as well as geographical vicinity."

The reservoir will be able to ensure supplies of fresh water for up to 68 consecutive days during the salt tide periods, when it is impossible to draw fresh water from the Yangtze, Chen said.

(China Daily January 16, 2008)