The delay of the South-to-North Water Diversion Project is accelerating the water crisis in the capital, where 17.55 million people are overdrawing inadequate supplies, experts said.

The project was planned to transfer 1 billion cubic meters of water to the capital in 2010, but its completion has been postponed until 2014.

According to Beijing's urban planning design (2004-2020), the city's annual water demand will be 4 to 5 billion cubic meters by 2020. The water diversion project will transfer at least 1 billion cubic meters of water every year.

The project is very important to alleviating the capital's water shortage, Wang Jianhua, a scientist with the China Institute of Water Resources and Hydropower Research, was quoted by Beijing media as saying in May. The city's current shortage has reached 400 million cubic meters, experts said.

The capital's urban planning design recommended that the capital's population be kept within 18 million. But it grew from nearly 17 million at the end of 2008 to at least 17.5 million a year later, Beijing government figures show.

Experts estimated that unless controlled, the city's population is likely to surpass 21 million, perhaps even reaching 25 million.

Since 1949, available per capita water has decreased from 1,000 cubic meters to less than 230 cubic meters as of 2008, less than 3.3 percent of the global average, Probe International's Beijing Water Report 2008 said.

Yu Yaping, director of Beijing Water Bureau's information department, told the Beijing Sci-Tech Report that nine straight years of drought have decreased the Miyun reservoir's annual storage volume.

The major water source's storage level is about 1.1 billion cubic meters, meaning more groundwater must be extracted.

The storage volume in Miyun and Guanting reservoirs, which supply more than 90 percent of Beijing's surface water, reached nearly 11 billion cubic meters in mid-June. That is about 200 million cubic meters less than the same period last year, Beijing Water Bureau's latest figures show.

The diversion project is designed to transfer water from the country's wet south to the drought-prone north along three routes (eastern, central and western), with most of it coming from the Yangtze River.

Officials have said the eastern route will eventually be able to annually transfer about 15 billion cubic meters of water and the central route will be able to send 13 billion to 14 billion cubic meters north each year.

As of April 2009, the water diversion project had cost nearly 54 billion yuan ($8 billion). Up to 540,000 people will eventually be resettled to make way for the middle and eastern routes, according to statistics from the project's construction office.