(Xinhua/Agencies)
Updated: 2008-05-15 06:52

The devastating earthquake that jolted Sichuan province on Monday has raised concerns over the stability of dams and infrastructure in the afflicted mountainous area, while landslides have blocked a river that flows to the region.

Heavy rains could compound the damage by hindering rescue work, triggering mudslides and adding to pressure on weakened dams, officials and State media said yesterday.

The quake left a swathe of collapsed buildings in the steep, rainy mountain range that runs from southwest to the northeast. The dramatic shelf where the Tibetan plateau collides with the Sichuan basin is ideal for hydropower, while doubling the challenges of building roads, bridges and railways.

One of the worst damaged cities is Dujiangyan, site of multiple dams and weirs that irrigate about 3 million hectares in the Sichuan plain. The Dujiangyan irrigation works date from the 3rd century BC, when engineers split the Minjiang River where it spills from the mountains, and diverted it to irrigate the plain.

"Upstream on the Minjiang River is Tulong, an important reservoir which is already threatened. If the danger intensifies, this could affect some power stations downstream," He Biao, deputy Party chief of Aba prefecture, told reporters.

The quake caused the 760-megawatt hydropower generating unit at Zipingpu, 9 kilometers upstream of Dujiangyan, to collapse, the provincial government said.

Water has been released at 50 percent more than average levels, to lower water levels in the Zipingpu reservoir and relieve pressure on the cracked dam, the Ministry of Water Resources said on its website.

"If Zipingpu develops a serious safety problem, it could bring disaster to Dujiangyan city downstream," where half a million people live, it said.

It has dispatched teams to Sichuan, Yunnan, Gansu and Shaanxi provinces and Chongqing municipality to prevent dams from bursting, it said.