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article imageChina's Three Gorges Dam has 'urgent' environmental problems

By Lynn Herrmann     May 20, 2011 in Environment
Shanghai - Environmental deterioration in the Three Gorges Dam region of China is forcing the government to acknowledge “urgent problems” which include landslides, seismic activity, relocations of citizens, and biodiversity loss.
China’s State Council held a meeting this week to address concerns associated with the controversial project, issuing a statement acknowledging problems connected with the dam, saying “Although the Three Gorges project provides huge comprehensive benefits, urgent problems must be resolved regarding the smooth relocation of residents, ecological protection and geological disaster prevention,” the New York Times reports.
A 17-year construction project carrying a $23 billion price tag, the 600-foot-tall Three Gorges Dam was eventually finished in May 2006. It began operation in 2008 and by the end of 2010 had generated 440 billion kwh of electricity. It is the world’s largest hydropower complex.
Rising water levels necessary for the dam to function have begun a long list of problems, and some experts believe the worst is yet to come, noting the sheer weight of water behind the dam as a major factor.
Scientists and environmentalists have long contended the Three Gorges Dam could lead to one of the country’s largest environmental disasters. Sitting behind the dam is a body of water 410 miles long - 60 miles longer than Lake Superior in the US - and 3,600 feet wide, twice as wide as the original river channel.
The Three Gorges project has a history of problems, and in some instances, people are losing their lives because of them.
In June 2003, state-owned China Yangtze Three Gorges Development Corporation (CTGPC) approved the first of three filling stages eventually leading to the lake’s depth of 575 feet, with the first increment filling the lake with 445 feet of water.
Scientists looked good, in a bad way, when just a month after the first increment was completed, a massive rock slide of around 700 million cubic feet dumped itself into the Qinggan River two miles from its confluence with the Yangtze River. The resulting 65-foot waves took the lives of 14 people.
Three years later the water level was increased to 512 feet and since then, one 20-mile section of the river has become prone to landslides. In November, 2007, in Badong County, the ground gave way at the entrance to a railway tunnel near a Three Gorges tributary and 4,000 cubic yards of rock and dirt poured onto a highway. The landslide killed 30 people, burying them in a bus they were traveling in.
Those landslides are believed to be directly related to filling the reservoir. Scientists in China have noted the water first seeps into loose soil at the base of area cliffs, destabilizing the land, thus setting up conditions for the landslides.
Water level fluctuations add further to the deteriorating effects. Dam engineers lower the lake’s levels in summer months to accommodate for upstream flooding. Levels are increased at the end of flood season for power generation. The change in water pressure adds to further land disturbances.
Scientific American (SA) reports scholars at South China Normal University predicted these water level fluctuations may increase activity in 283 landslide-vulnerable areas. Such fluctuations are apparently the source of a 655-foot wide crack which occurred in 2007 just behind the village of Miaohe, located 10 miles upstream of the Yangtze.
The land split occurred shortly after the reservoir’s water level was lowered for summer flood season. As a result, 99 villagers were relocated to a mountain tunnel, where they were forced to camp for three months.
China s May 2008 earthquake in Sichuan province.
China's May 2008 earthquake in Sichuan province.
Remko Tanis/flickr
Compounding the already experienced problems, the Yangtze sits on two major geological faults: the Zigui-Badong and the Jiuwanxi. Due to the sheer weight of water behind the dam, alterations of the reservoir’s water level to accommodate for floods could put a strain on those faults. The Chines government has denied any connection between the reservoir and a May 2008 earthquake in Sichuan Province that claimed the lives of 87,000 people.
Reservoir-induced seismicity, the link between dams and temblors, is believed to be responsible for at least 19 earthquakes in China over the last five decades, ranging from small tremors to a 6.1 magnitude quake in 1962 near Xinfengjiang Dam in Guangdong province.
“When you alter the fault line’s mechanical state, it can cause fault activity to intensify and induce earthquakes, said Fan Xiao, a geologist at China’s Bureau of Geological Exploration and Exploitation of Mineral Resources, according to SA.
A huge relocation effort occurred because of the Three Gorges project. More than 1.2 million people were ordered evacuated from two cities and 116 towns along the now-inundated banks of the Yangtze River.
Some villagers, relocated because of the reservoir’s rising waters, have been moved a second time because of the landslide and tremor activity. In some instances, according to local news media, some of the villagers have received only half of the acreage they had been promised by the government. Earlier reports state some of the people had received compensation stipends equivalent to $7 a month.
However, the government statement this week has pledged to address the concerns of citizens impacted by the displacement, saying it will increase the standard of living by 2020 for those citizens associated with the relocation effort.
Flood damage along China s Yangtze River.
Flood damage along China's Yangtze River.
Heavy rains and flooding in 2010 washed tons of trash and litter into the reservoir, with garbage so thick it threatened to clog the dam. An intense clean-up effort was required to help ease those pressures.
Changing weather patterns in the region are believed linked to the Three Gorges project. Increased drought and increased flood events are taking a toll on plants and animals, with reproduction patterns being altered.
In January, 2008, the Yangtze reached its lowest level in 142 years, stranding dozens of boats and ships in Hubei and Jiangxi provinces, SA reports. Some estimate the river’s flow volume has been reduced by as much as 50 percent.
Increasing the problem, China has approved a highly controversial $62 billion scheme which will divert water from the Yangtze to northern China through a series of canals and tunnels, projected to be completed by 2050.
Downstream from Three Gorges, where the Yangtze meets the East China Sea, are some of the highest concentrations of human habitation on the planet, including Shanghai, China’s largest city. Decreased flow of river water has led to water shortages in the city. Salt water now moves further upstream, bringing with it an influx of jellyfish competing with native river fish by eating their food, eggs and larvae.
Overfishing in the area has led to almost 15 percent of the river’s unique fish species becoming endangered.
Some scientists believe many of those fish evolved over time in relation to the Yangtze flood plain, but the dam has decreased downstream flooding, an essential component of downstream lakes. Lowered water levels downstream are putting pressures on many fish survivability rates. Three Gorges has helped contribute to the baiji dolphin’s decline, so rare it is now considered functionally extinct.
Prior to Three Gorges, flooding along the lower Yangtze kept a parasitic snail population in check. Now, decreased river flow has led to an explosion of these snails which transmit a blood parasite, schistosomiasis, to humans who swim or wade in the contaminated fresh water. A spike of the disease has been recorded in some areas.
Such changes in microbial waterborne diseases could lead to other changes as well.
Aerial view of Yangtze River and Three Gorges Dam.
Aerial view of Yangtze River and Three Gorges Dam.
Euclid vanderKroew/flickr
Government officials claim they have spent billions of dollars in addressing these issues, including at least $1.6 billion in shoring up landslide-prone areas. In 2008, a proposed $3.2 billion was to be spent on water cleanup alone. Attaining water quality targets continues to be a major challenge for the government, despite cleanup efforts first initiated in 2001.
New dams are being built in attempts at alleviating sedimentation problems associated with the Three Gorges Dam. An additional 12 dams are being proposed for the upper Yangtze to help wean the country off its coal addiction. China hopes to receive 15 percent of its power from renewable resources by 2020, with one-third of that coming from hydropower.
A government website noted officials at this week’s meeting have
vowed to stick to the principle of putting people first and promoting sustainable development in post-construction work.
More about yangtze river, Three gorges dam, Dam, River, relocate
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