The safety of the world's oldest operating irrigation system was not compromised by Monday's quake, though the system sustained minor damage, the Ministry of Water Resources said on Wednesday.

The quake caused cracks in the V-shaped dike of the Dujiangyan project, which is more than 2,000 years old, and there were collapses in a sluice control room and a standby power generator room, it said.

The city of Dujiangyan, near the epicenter in Wenchuan County, was one of the worst-hit regions in the 7.8-magnitude earthquake.

The ministry urged protection of the Zipingpu Reservoir between Dujiangyan and Wenchuan, and on the upper stream to Dujiangyan.

It said the irrigation system and Dujiangyan City "would be swamped" if major problems emerged at the dam at the reservoir.

The emergency response office of the Sichuan government said on Tuesday that cracks had appeared on the surface of the dam at Zipingpu and workshops collapsed, while all hydropower generators came to a halt.

The ministry set up a command center at Zipingpu to safely discharge the reservoir's rising waters and guarantee that the damage posed no threat to Dujiangyan and the neighboring Chengdu Plain.

The Dujiangyan project, built in 256 BC, is more than 50 kilometers from the provincial capital of Chengdu and irrigates 666,000 hectares of land, including Chengdu.

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.

(Xinhua News Agency May 14, 2008)