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Dunhuang Heritage Protected from Moving Sand
Chinese scientists have achieved success in protecting the world-class heritage relics in northwest China's Dunhuang from being damaged by encroaching sand from nearby deserts.
Located at the western end of the arid Gansu Corridor, Dunhuang 's famous Mogao Grottoes with their priceless murals have long been under threat from moving dunes from Mingsha Hill, which is only 1,500 meters from the caves.
There have been worries that the sand might eventually bury the 1,600-year-old site, which was put on the World Heritage List by the United Nations Educational, Scientific and Cultural Organization in 1987.
"Long-term research has suggested that the biggest threat is not the moving dunes but the sand blown by the wind from Mingsha Hill. So we have taken measures to curb it," said Wang Wanfu, deputy director of the Conservation Institute of the Dunhuang Academy, a center of Dunhuang studies.
A three-step project built to obstruct and fix the sand has helped reduce the annual amount of sand invading the cave area by 70 percent, he said.
The first step was to grow some desert plants at the foot of Mingsha Hill to fix the sand. Now, a 2,000-meter-long and 12-meter- wide shelterbelt of vegetation blocks 5,400 cubic meters of loose sand, while reducing the wind speed by 20 percent, Wang said.
The scientists adopted a system which conveys water directly to the root of each plant through perforated pipes, to ensure the plants survive the extremely dry environment.
Monitoring results showed that the establishment of nylon fencing around the caves, the second step, has stopped more than 95 percent of the sand moving toward the caves.
The final weapon used to curb soil erosion and drifting sand is silicon emulsion, which is sprayed to fix the sandy surface on the top of the caves, Wang explained.
The conservation work was jointly conducted by specialists from Wang's institute, the Lanzhou Desert Research Institute under the Chinese Academy of Sciences and the Getty Conservation Institute of the United States.
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