All the barrier lakes (or quake lakes) formed after the massive May 12 earthquake in southwest China's Sichuan Province are "under control" but the situation is still grim, said Vice Minister of Water Resources E Jingping on Sunday.

Photo taken on May 22, 2008 shows an airscape of the quake lakes formed after the massive May 12 earthquake in Beichuan County, southwest China's Sichuan Province. According to a preliminary analysis, a total of 34 quake lakes have been found in Sichuan, eight of which contain more than 300 million cubic meters of water each.

Heavy rains forecast for the area over the next three days are a major threat, as the additional water build-up in the lakes could cause the landslide barriers that formed them to burst, flooding nearby areas, E told a news conference.

The 8.0-magnitude earthquake, aftershocks and landslides created 35 such lakes, with 34 in Sichuan, posing a new danger to more than 700,000 of the people who survived the deadly quake, the vice minister said.

E admitted that these lakes posed a challenge for the government's efforts to prevent secondary disasters in the quake regions.

The biggest concern is the Tangjiashan lake, the largest of the 34 quake lakes in Sichuan, whose water level rose by nearly 2 meters Saturday to 723 meters, only 29 meters below the lowest part of the barrier.

About 1,600 armed police officers and People's Liberation Army soldiers were hiking on Sunday toward the Tangjiashan lake, hoping to blast away its landslide barrier before it bursts and causes a flood.

Earlier attempts to send military helicopters on the same mission were hampered by adverse weather and low visibility at the lake.

The ministry has drawn up evacuation plans for communities downstream of the 19 quake lakes at high risk of bursting, E said. He did not provide an estimate of the people who might have to move.

The massive earthquake also left 69 reservoirs in danger of collapse in Sichuan. Another 310 reservoirs were in "highly dangerous" situations and more than 1,400 posed a moderate risk, according to E.

Steps have been taken to tackle the problem, E said, such as completely draining the 69 collapse-prone reservoirs, lowering water levels at 826 others and putting all the damaged reservoirs under 24-hour observation.

The ministry wants to fix the reservoirs in the "highly dangerous" and more risky categories before July, when the rainy season is expected to start in the quake regions, he said.

Priority has been given to the Zipingpu dam, which is only 17 kilometers from the quake epicenter of Wenchuan County and would threaten 11 million lives on the downstream Chengdu Plain if it collapsed, E said. However, he said, the dam was structurally stable and safe despite some minor damage.

After planned explosion, experts opened wider the mouth of a major barrier lake on Shiting River Sunday afternoon, which was about 5 kilometers upstream from Hongbai County of Shifang City. The mouth width almost doubled to 17.3 meters, with per second discharge increased by 8.8 cubic meters to 30.4 cubic meters, according to the Ministry of Water Resources.

The lake was the most dangerous one among the six formed in Shifang after the earthquake.

Meanwhile, 803 hydropower stations were damaged in the quake nationwide, including 481 in Sichuan.

(Xinhua News Agency May 26, 2008)