Troops prepare for the worst as dam springs a leak Residents of Mianyang held their breath yesterday as rising waters in the Tangjiashan 'quake lake' threatened to unleash a deluge at any moment Water levels in the dam created when the May 12 earthquake sent boulders and mudslides into the Jian River in Beichuan rose to 738.8 metres by 5pm, just below its 740-metre-high wall. The water level has risen 1 metre a day this week. The Sichuan meteorological bureau said showers could be expected in Beichuan last night. And just 2mm of rainfall over an area of 3,350 square meters upstream from the lake would push the water level up 1 metre, experts said. 'Water is already seeping through the dam wall,' a spokesman at the lake control centre said. The water would probably flow over the top of the dam tonight, one irrigation expert said. He declined to give his name because all experts were barred from speaking to the media during the crisis. But the expert said the best scenario would be for the water to build up pressure and burst through the dam at a spot where the soil was particularly loose, and connect to the head of an already dug run-off channel, allowing for a controlled draining of the dam. The authorities are pinning their hopes on a 475-metre long, 11-metre deep run-off channel - scooped out after six days and nights of non-stop digging by hundreds of engineers and soldiers. 'We actually want the dam to burst in a controlled way. Otherwise, the dam will never be safe,' the expert said. 'But at the current rate of water flow of 75 cubic meters per second, the water pressure would not be strong enough to burst the dam. We will have to discuss what to do when that happens.' Unforeseen factors have increased the likelihood of a dam burst, whether controlled or uncontrolled. Liu Ning , head of the dam control expert team, said earlier that there was a 93 per cent likelihood of a burst, with factors like fresh mudslides, higher-than-expected rainfall and aftershocks adding uncertainties to the situation. Meanwhile, in Mianyang and villages downstream, residents and troops were on high alert. The dam now holds more than 200 million cubic meters of water and would cause a flood up to 36 metres deep in the village closest to the dam. In Mianyang's low-lying Shenjiaba area, red lines have been marked on building walls and lamp posts indicating how far the water would rise if up to half the water was released. Evacuation plans have been drawn up according to two scenarios. Everybody living in areas that would be affected by a 'one-third dam burst' had been compulsorily evacuated, while all others at risk in the case of a complete dam collapse have gone through drills and learned escape routes. In Jiulin township, the last major township before Mianyang, a 670-strong bridge and boat division of the Chengdu PLA helped with last-minute evacuations. Special troops were also preparing for the collapse of a major pipe supplying petrol from Lanzhou to Chongqing via Chengdu . If that happened, it could affect provinces like Yunnan and Guizhou . The underground pipe was designed to withstand 6,000 cubic meters of water rushing past it per second, but a one-third collapse of the dam would send water travelling at twice that speed, said the troops' commander-in-chief, Colonel Liu Yongzhan . A squad of soldiers was on standby to build a 200-metre-long support bridge within two hours should the pipe break. The bridge would allow the oil company to rebuild the pipe within 48 hours, a mission that would otherwise take a month. The troops were also there in case some residents were washed away. A lieutenant-colonel said some people were still refusing to leave during the evacuation. 'One minute they said they wanted to go back to get some clothes; the next minute they said they needed to go back and feed the pigs,' he said. 'Perhaps some did not believe the flood was coming, given they have been told from around May 20 that the dam would burst.' Troops were standing guard at the entrance to every settlement to make sure no residents returned to their homes, and small patrols of government workers and volunteers were double-checking that no one was be left behind. The patrols would continue until up to two hours before the floods were due to arrive. If the deluge comes, it is expected to reach Jiulin in about two hours. Half an hour's drive away in Mianyang, residents evacuated from Shenjiaba have been camping on Fule Mountain for 10 days, but not every one has been supplied with bottled water and food as promised. 'Residents of other Shenjiaba regions have already been provided subsidies, but not us,' a woman from Luduchi said. 'We have received nothing so far, not even a waterrepellent sheet.' At a glance 69,127 confirmed dead 17,918 missing 373,612 injured 43.7b yuan in donations received from home and abroad Source: Xinhua
