Ten years is not a short time, but the 33.5 million people living in the Taihu Lake area in East China will have to wait another decade to drink clean water from the country's third largest freshwater lake.

After a decade of treatment costing billions of yuan, Taihu Lake still cannot offer clean drinking water due to worsening pollution, even though it has been playing a key role in fighting floods in the area.

Covering an area of 2,400 square kilometres, Taihu Lake is a major source of drinking water for people living in Shanghai and East China's Jiangsu and Zhejiang provinces.

Historically known as a rich area, the Taihu Lake basin, whose land area and population account around 3 per cent and 8 per cent of the country's total, has become one the most populous and prosperous regions in the country.

But tremendous economic growth and the huge population of the area are putting the lake under increasing environmental pressure, resulting in deteriorating water quality in recent years.

Pollution problems

A struggle then took place between efforts to curb flooding and tackle pollution.

After 10 years, a series of core projects have been completed to curb the flooding of Taihu Lake, Vice-Minister of Water Resources Zhai Haohui told a recent high-profile seminar in Shanghai.

These projects, Zhai added, had established a framework for flood control and the utilization of water resources.

According to Zhai's ministry, the first-phase Taihu Lake projects have produced 15.8 billion yuan (US$1.9 billion) in economic benefits, two-and-a-half times the original investment.

"For example, these projects played an important role in combating the massive flooding of Taihu Lake basin in 1999, saving 9.2 billion yuan (US$1.1 billion)," said Sun Jichang, director of the administrative bureau of Taihu Lake basin under the Ministry of Water Resources.

However, compared with the social development of the entire area, the flood control standards are low and the pollution of the lake remains serious, officials noted.

During the Taihu seminar held on December 3, Vice-Minister Zhai pledged that people living in the Taihu Lake area will be able to drink "clean water" from the lake by 2015.

"(If the goal could be realized,) that would really be a great achievement," said senior geographer Shi Yafeng from Chinese Academy of Sciences.

Meanwhile, experts pointed out that the quality of Taihu Lake continues to deteriorate despite the more than decade-long efforts of both the central government and local authorities regarding the treatment of the lake.

Local industries and people living in the area had already seriously polluted the lake by 2001.

The environmental problems in the lake comprise general eutrophication (nutrient enrichment with nitrogen and phosphorus), oxygen depletion and probably also contamination with xenobiotics (substances dangerous to the environment) originating from increased agricultural, domestic and industrial pollution, experts said.

Nitrogen and phosphorus discharged into the lake has caused an overgrowth of algae, further deteriorating the water quality.

More treatment urged

The State Environmental Protection Administration (SEPA), the nation's top environmental watchdog, has been carrying out close monitoring on water quality of the Taihu Lake using 110 manned and three automatic surveillance stations throughout the entire area of the lake.

In the early 1990s, experts estimated that the annual industrial sewage entering the lake would reach 540 million tons and household sewage would reach 320 million tons; Meanwhile, spot checks conducted in 2000 indicated the total sewage surpassed 5.3 billion tons.

SEPA officials said by 2005, sewage treatment plants in the Taihu Lake region will have a capacity of 2.17 million tons of sewage per day, nearly 30 per cent more than the 1.67 million tons per day required by the 10th Five-Year Plan (2001-05).

A total of 243 projects will be constructed to treat waste water and rubbish, remove silt and reduce pollution from farming and ships. These projects will cost 21.9 billion yuan (US$2.6 billion), according to SEPA.

One of the most basic causes of the pollution lies in the sewage treatment measures lagging far behind the rapid social and economic development in the Yangtze River delta, experts said.

According to Sun, the director, only 30 per cent of the household sewage is treated before flowing into the lake.

At the same time, the treatment measures and standards of sewage and waste water could not meet the requirement of new situation, said Gao Erkun, an official with the Ministry of Water Resources.

Even if all the waste water produced in this region was treated in accordance with current standards, it still exceeds the capacity of the basin, Sun said.

Local people and enterprises that have benefited from the region's rapid industrialization and urbanization in the past two decades now have to pay for the treatment of waste water and rubbish.

Under the auspices of the State Council, some cities in the region began to seek water resources through cross-regional water transmission.

Enjoying a convenient location that neighbours the Yangtze River, the cities of Suzhou, Changzhou and Wuxi have utilized the river water to drive their rapid economic development for many years.

During the past three years, the Taihu Lake area borrowed more than 6 billion cubic metres of water from the Yangtze River and half of this flowed into the lake itself.

Meanwhile, a reasonable and cautious attitude must be adopted with regard to cross-regional water transmission, experts warned.

"No doubt, the quality of the Yangtze and Qiantang rivers is better than that of the Taihu Lake," said Chen Jiyu, an academician with the Chinese Academy of Engineering. "However, it should be noted that these rivers themselves are suffering from increasingly serious pollution."

Therefore, the fundamental way to improve the quality of the lakes and rivers is to solve the pollution issue as well as adopting measures to save water, he noted.

(China Daily 12/17/2004 page5)