The encroaching Kumutage desert is threatening the Mogao grottoes in Dunhuang, Gansu Province, a scientist warned yesterday.

The Shule River, which runs through the Dunhuang oasis, has so many dams on it that its waters are shrinking, said Wang Jiru, director of the Gansu Desert Control Institute in Wuwei, Gansu.

A man passed by a desertification area in Yangjiaqiao Village, Duhuang City of Gansu Province.

The institute, which is situated near the desert's edge, has been monitoring the desert's shifting sands over the past four decades.

It has found the sixth largest desert in China, covering 20,000 sq km, growing between 1-4 m every year since 2004.

The 1,600-year-old Mogao grottoes are just 50 km east of the desert. Its caves are famous for their statues, wall paintings and 1,000 years of Buddhist art.

They are being damaged by sand blown from the desert and in the future could be buried by the drifting sands, Wang said.

The desert is expanding because there is less water in the Shule river to its east. Increased agriculture in the Dunhuang oasis and damming on the river since the 1960s has dried up the area, Wang said.

As the desert expands there is less vegetation, fewer wild camels and other animals, he added.

Desertification in the country is a serious problem. The desert has almost covered Minqin County in Gansu.

It is moving 8-10 m a year along the chain of oases known as the Hexi Corridor.

The corridor once connected China's central plains with the grasslands in the Xinjiang Uygur Autonomous Region and separated the Tengger and Badain Jaran deserts.

Building dams was one of the reasons Minqin has been devastated, Wang said. Residents also dug up more than 10,000 wells, exacerbating the situation.

The dry Danghe River course in Yangjiaqiao Village, Duhuang City of Gansu Province

(China Daily November 6, 2007)