Located in a river valley, Wenchuan's climate is nevertheless hot and arid. Its average annual precipitation is less than 500 mm, even lower than Beijing's 585 mm. This makes it hard for trees and grass to grow on the mountain slopes. Most of its precipitation also falls between June and August, with rainstorms giving rise to mudslides that are fatal to the area's sparse vegetation.

Over the past two decades, the Wenchuan government has been making efforts to grow trees on the mountains, but to no avail.

On the hills surrounding its county seat, there are only occasional clumps of shrub, offering visual relief from its drab slopes. The sizzling sunshine and relentless wind have been eroding rocks and the boulders on the mountain for years, slowly reducing them into sand and dust.

On sunny afternoons, strong wind in the valley would blow up the sand and dust, forming a huge yellow expanse that blankets the whole county. The earthquake, which added more than 300 hazardous spots such as landslides around the county seat, made the environmental situation worse.

Local residents say they have been suffering daylong sandstorms for half a month following the quake.

Wang Songbai, director of the People's Hospital in Wenchuan, says the hospital received more than 3,800 patients suffering from respiratory diseases in the month after the quake, compared with less than 400 in the same period last year.

"The worsening sandstorms are the main reason for these cases," Wang said. "Living in such an environment is like staying in a concrete-producing factory without wearing a mask."

Although a heavy dose of rain helps reduce the dust in the air, it creates another problem: mudslides.

Official figures show that the quake destroyed more than half of Wenchuan's arable land, mostly through landsides and mudslides. Experts say it will take about a decade for the mudslides to subside in quake zones, which pose a constant threat to those living in the mountains.

On June 17, about 10,000 people were evacuated from Wenchuan's mountainous villages, as continuous downpour over the past days threatened to trigger severe landslides.

Liu Hanxiu, 56, is one of the 659 villagers evacuated from the Tongshan village on that day. According to her, the mudslides destroyed almost half of the village's 50-hectare farmland. It also blocked the only water ditch in her village, cutting out its sole drinking water source as well as creating a huge quake lake in the valley behind their homes.

Ten days after being evacuated, few people in Liu's village were willing to return to their homes. They feared the collapse of the quake lake.

"The villagers don't want to go back," said Liu, a member of the Qiang ethnic group.

"Some in our village have lost their land completely. How can they make a living without a single inch of farmland?"

Crucial decisions

The authorities have not decided on whether to relocate Wenchuan's county seat completely, said Tang Kai, director of the urban planning department of the Ministry of Housing and Urban-Rural Development, in a press conference held on July 9.

"The shortage of land in quake-devastated counties is the major obstacle in choosing a new site," Tang said.

Most quake-stricken regions are already overpopulated. Wenchuan's natural environment is suitable for supporting about 50,000 people, rather than its existing population of 110,000, a report by the Institute of Mountain Hazards and Environment under China's Academy of Sciences showed.

"Relocation will be a very complicated and difficult task, especially for the local government ," said Yin from Tsinghua University.

"The central government will have to carve out new administrative areas for the relocated population, which may incur conflicts of interest among different regional governments," Yin said.

"Whatever the difficulties, the right decision must be made.

"Otherwise it will be like laying a weak foundation for future tragedies."

(China Daily July 16, 2008)