An ongoing problem

The lack of good-quality fresh water has been a problem for the city for a long time. Before the Qingcaosha reservoir was completed in 2010, the water supply changed sources several times.

In 1911, the initial major drinking water resource in Shanghai was Suzhou Creek when the first water works were built in today's Zhabei district. Later, because of the pollution in Suzhou Creek, the water intake was moved to downstream Huangpu River. By 1978, the Huangpu River was also seriously polluted and the intake was moved again and again over the next 20 years along the upper sections of Huangpu River.

Before the establishment of the Qingcaosha reservoir, the city relied on Huangpu River for 70 percent of its water with the other 30 percent coming from the Yangtze River.

But the source of the Huangpu River, Taihu Lake, was also becoming polluted by eutrophication (an oversupply of nitrogen and phosphorus) and this pushed authorities to find a new water supply.

Xu Xuehong, the deputy director of the Water Resources Protection Bureau for the Taihu Basin, told the Global Times that if Shanghai continued to take water from the Huangpu River, the entire river ecosystem would face a crisis.  

Last month, Shanghai's neighbor city, Hangzhou, moved to improve its water supply. Because of growing pollution in the Qiantang River, the current water source for Hangzhou, the city authorities plan to draw water from Qiandao Lake to guarantee a water supply for the city's 8.7 million people.

However the plan has been heavily criticized by experts and citizens for its expense with many arguing that the government should use such a large amount of money to fight pollution rather than to import water from hundreds of kilometers away.

The biggest threat

According to Professor Chen Zhenlou, with the School of Resources and Environment at East China Normal University, the biggest threat for Shanghai's water resources was pollution from the upper reaches of the Yangtze River, mostly caused by illegal factory discharges and domestic sewage.

"Even though Shanghai has done a perfect job in protecting and managing the Qingcaosha reservoir, the pollution coming from the upper stream is like the sword of Damocles threatening water supplies in Shanghai," Chen told the Economy & Nation Weekly.

Chen was not being paranoid. A survey conducted by the Ministry of Environmental Protection in December last year revealed that 81 percent of some 7,555 chemical and petrochemical industry projects under construction were being sited by rivers or in densely-populated areas. Forty-five percent of these projects were considered high risks.

Along the Yangtze River there are some 400,000 chemical plants, five major iron and steel plants and seven major refineries. The threat from the chemical industry is especially obvious in lower reaches of the Yangtze River, according to experts. From Nanjing to Shanghai, eight major chemical industrial zones spread along the banks of the Yangtze River.

"They are time bombs. If anything happens to these chemical factories, it could be a disaster for Shanghai," said Shen Jianhua, a senior researcher with the Shanghai Institute for Biological Sciences.

Officials from Shanghai Water Authority admitted at a government meeting recently that the security measures in place at the Qingcaosha reservoir are probably inadequate in the case of a major pollution threat upstream. Chief engineer Chen Guoguang said that the authority was working hard to improve methods of handling emergencies.