China's huge south-to-north water diversion project entered a crucial stage on Monday as the dam heightening project at Danjiangkou Reservoir in central China got underway.

The height of the dam will be raised by 15 meters to 175 meters over five years, which is a key project to ensure the effective diversion of 20 billion cubic meters of water to the arid northern and northwestern parts of the country by 2010, according to Ning Yuan, deputy director of the South-North Water Diversion Project Office of the State Council.

The Danjiangkou Reservoir was built in 1958, and is the center of the massive south-to-north water diversion project. It was put into operation in 1973.

When the dam works are completed, the reservoir will have a bigger storage capacity -- enlarged by 11.6 billion cubic meters -- and a larger land area -- expanded from 745 sq km to 1,050 sq km, Ning said.

Water will be diverted from the upper, middle and lower reaches of the Yangtze River to the northern and northwestern parts of China through western, central and eastern routes. Construction of the eastern and central routes began in 2002 and 2003 respectively.

Between 2002 and 2010, some 20 billion cubic meters of water will be diverted from south to north, about 9.5 billion cubic meters from the Danjiangkou Reservoir.

In about 40 to 50 years, 44.8 billion cubic meters of water will be diverted, which is equal to the total water volume of the Yellow River, the country's second largest river.

According to Ning, the dam project should be completed by 2010. By then, water will be diverted through a 1,420-km-long trunk canal to moisten and irrigate the arid northern lands.

When the entire project is completed, about a dozen provinces, municipalities and autonomous regions in north China including Beijing, Tianjin, Hebei, Henan, Shandong, Qinghai, Gansu, Ningxia, Inner Mongolia, Shaanxi and Shanxi -- or about 300 million people -- will benefit from it.

These areas produce one third of the country's grain output and gross domestic product, but operate on merely a fifth of the country's average per capita water resources.

The project, estimated to cost a total of 486 billion yuan (US$60 billion), will have a far-reaching impact on the sustainable development of the country, and benefit generations of Chinese to come, Wu Xinmu, an economist and professor with Wuhan University, said.

China is short of water resources in general, Wu said, with average per capita access to water resources accounting for merely a quarter of the world's average.

The distribution of water resources is uneven throughout the country. It is rich in the south and deficient in the north.

The proposal for a water diversion project was first put forward by the late Chairman Mao Zedong in 1952.

(Xinhua News Agency September 27, 2005)