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CHENGDU, June 4 (Xinhua) -- The plan to drain the Tangjiashan "quake
lake" in southwest China's Sichuan Province is due to be implemented
by Thursday or thereafter, with the trapped water volume having
risen to 211.6 million cubic meters as of 2 p.m. Wednesday.
The volume was 200.8 million cubic meters at 8 a.m. Tuesday,
according to the quake control and relief headquarters with the
Ministry of Water Resources (MWR).
The water level has been moving higher. It stood at 737.78 meters at
2 p.m. Wednesday, up 0.25 meters from 8 a.m. The water level was
just 1.37 meters from the lowest point of the blockage.
"We must prepare for dealing with the worst situation but strive for
the best results," said Chen Lei, minister of water resources, at a
meeting on Wednesday in Sichuan.
He stressed great efforts should be made to guarantee smooth
drainage of the quake lake to "ensure the safety of people
downstream".
To prevent the quake-formed lake from breaching its barrier and
endangering survivors downstream, more than 600 armed police and
soldiers raced to complete a water diversion facility on Saturday
night, digging a 475 meter channel in the barrier.
The timing of actually draining the lake, however, will be decided
by water inflows from its upper reaches, said Liu Ning, MWR Chief
Engineer.
According to Liu, the catchment area of the upper reaches covers
3,350 sq km. It is estimated that a 2 mm rainfall in that area will
mean a rise of 1 meter in the water level before the quake lake
barrier.
Weather experts consulted by the Sichuan Provincial Bureau of
Meteorology on Tuesday predicted scattered thundershowers and two
more rainy days on Thursday and Friday around Tangjiashan lake, with
rainfall to peak on Thursday night and hit 20 mm.
According to weather records, rainfall for June, July and August
over the Tangjiashan area stands at 140 mm, 360 mm and 330 mm,
respectively. Rainfalls of such levels would pose a grave danger to
the quake lake.
Here are some key statistics regarding the May 12 quake, Tangjiashan
lake and efforts to avoid further emergencies:
Human toll -- The number of those killed was 69,122 as of Wednesday
noon, the Information Office of the State Council said. Another
373,606 people were injured and 17,991 others remain missing, while
45.69 million people were affected by the disaster.
Tangjiashan lake -- One of 35 lakes formed after landslides
triggered by the quake blocked rivers in the mountains. Tangjiashan
lake, which sits on the Jianjiang River, a local waterway, is 3.2 km
from the seat of the hard-hit Beichuan County. It is inaccessible by
road and can only be reached by foot or air.
Evacuation plans -- There are three plans to move survivors if
necessary. The target is zero deaths, according to Tan Li, Mianyang
City Communist Party chief and also chief of its Quake Control and
Relief Headquarters. In the first instance, 158,000 people will have
to relocate if one-third of the lake breaches its banks. Actually,
more than 250,000 people in Mianyang City have already been
relocated.
Two other plans require the relocation of 1.2 million people if half
the lake volume is released or 1.3 million if the barrier fully
opens.
Water diversion channel -- A 475 meter channel was cut into the
Tangjiashan lake barrier by 620 armed police and engineers over six
days and nights. The cubical channel is 12 meters deep and 7 meters
wide upstream and in the middle but becomes larger downstream. Most
of the workers have already left the site. A dozen police stayed
behind to monitor the situation.
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