Although investment may be flooding into China's booming economy, the country's vital water resources are stuttering to a trickle, a senior expert has warned.

According to Liu Ning, chief engineer of the Ministry of Water Resources, about 25 percent of all groundwater is contaminated with pollution.

More than half of groundwater in plain areas, which cover 1.15 million square kilometers, is below drinking water standard, and the groundwater in more than half of China's cities is "severely polluted," said Liu.

"The strain on water resources is increasing along with rapid economic and social development," Liu said at a forum in Xinyang, Henan Province on Tuesday.

Water consumption in some areas has far exceeded the resources available, causing the drying up of rivers, lakes and wetlands, and exacerbating pollution, Liu said.

"This has created a potential, and in some ways direct, threat to the security of the environment and the economy," he added.

Official statistics show there are 164 regions, covering an area of 190,000 square kilometers, where too much water is being taken from the environment. It is reckoned that, all together, more than 10 billion cubic meters of water too many have been tapped.

Subsidence, a result of excessive water extraction, has affected 64,000 square kilometers, including land in 50 cities.

Meanwhile, the country's sewage output reached 68 billion tons in 2003, more than triple the 1980 level. About a third of industrial sewage and two thirds of domestic sewage were discharged without any treatment.

"In some areas where the ecosystem is fragile, water resources are so badly degraded it affects people's daily lives and threatens social and economic development," said Liu.

According to Liu's ministry, more than 90 rivers in the country, including the major Yellow and Liaohe rivers, have run dry. Compared to the 1950s, the size of lakes across the country has decreased by 15 percent, while natural wetlands have retreated 26 percent.

(China Daily October 28, 2005)