Minister of Water Resources Chen Lei said in Beijing on Thursday that damaged water infrastructure, including reservoirs and hydropower plants, posed serious threats to flood control and security in earthquake-stricken regions, particularly in the hardest-hit province of Sichuan.

Chen, who is also head of the ministry's command center for disaster rescue and relief operations, said the southwestern province had a large number of reservoirs, many of which had sustained significant but still unknown damage during Monday's 7.8-magnitude quake.

Also unknown was the extent of damage to hydropower plants owing to inadequate management systems and poor data collection, he said.

It was crucial to prevent secondary disasters and control floods at damaged reservoirs, hydropower plants and dikes, he stressed.

He noted that it is necessary to study and judge potential dangers at these facilities by analyzing satellite and other aerial images.

If necessary, downstream residents should be evacuated, he said.

Earlier in the day, the Water Resources Ministry said the Zipingpu dam, near the quake epicenter in Wenchuan County is structurally stable and safe.

But the multi-functional facility sustained a range of damage during the quake, including cracks at the top and collapsed workshops, according to the Emergency Response Office of the Sichuan Provincial Government.

Another key water project in Sichuan, the Dujiangyan irrigation system, which was more than 2,000 years old, was also reported safe after Monday's quake.

Sichuan has other major water projects, including the south-to-north water diversion project and the Three Gorges Dam, both of which reported no impact from the quake.

The devastating quake was centered in Wenchuan County, 159 kilometers northwest of Chengdu, Sichuan's capital. The death toll as of Wednesday afternoon was put at 14,866.

(Xinhua News Agency May 15, 2008)