A major sluice gate opened on Sunday at the upper Yellow River, China's second longest, to alleviate floodwater pressure caused by an ice run blockage. Officials said that opening the gate would avert dam bursts and consequent threats to people and property.

The sluice gate for the general irrigation channel in the Hetao area of northern Inner Mongolia will help distribute 220 million cubic meters of water, which has accumulated to levels about 50 percent higher than in normal years, said Yellow River Conservancy Committee official Zhang Jinliang.

Sections of the river freeze and thaw at different times. When an ice run flows to a frozen section, it can become blocked. If the blockage persists, water levels may rise and cause floods and dam bursts, threatening lives and property. The ice-run phenomenon takes place at the start of winter and spring.

A 210-kilometer section of the river's 260-km stretch in upper Ningxia Hui Autonomous Region has thawed, but further downstream, high-altitude Inner Mongolia still has a 720-km frozen section, Zhang said. The Inner Mongolia section is expected to begin to thaw in mid-March.

The water in the Inner Mongolia section has hit 1.8 billion cubic meters, half again the level of normal years, so action must be taken to prevent dams from bursting, according to the official.

The distribution will last half a month as water is directed into the irrigation channel network in the Hetao area and a nearby desert.

The 5,464-km Yellow River originates in Qinghai Province in the northwest and flows through Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan and Shandong before emptying into the Bohai Sea.

(Xinhua News Agency March 10, 2008)