Wednesday, August 29, 2007
Three Gorges Dam Exacts Its Toll
2007-08-29, WSJ
THE MOST VAUNTED engineering marvel in China, the Three Gorges Dam project, is suffering from unforeseen problems including landslides and water pollution, raising new doubts about a project that has come to symbolize the country's effort to control its environment.
It was only a year ago that the massive Three Gorges Dam was completed, creating a reservoir on the Yangtze River some 640 kilometers long. Now, geologists say the trapped water's massive weight has begun to erode the Yangtze's steep shores at several spots. That, along with frequent fluctuations in water levels, has triggered a series of landslides and weakened the ground under places such as Miaohe, a village about 16 kilometers up the reservoir from the dam. Local officials worry that a whole mountainside here could collapse into the water, killing residents and threatening a vital shipping lane.
There are additional dangers. Chinese scientists say that as the dam blocks silt heading downstream, the Yangtze River estuary region, which includes Shanghai, is shrinking and salt water from the ocean is flowing further inland. A report this spring by the World Wildlife Federation said water flowing through the dam is now moving faster, damaging the downriver dikes that were built to prevent floods. Raw sewage and fertilizer runoff has fouled the reservoir, nourishing giant algae blooms and threatening downstream water supplies. Fluctuating reservoir levels have even been blamed for a bizarre plague of rats that farmers have been battling in central China's Hunan Province.
The emerging issues at Three Gorges illustrate this rapidly industrializing country's struggle against the constraints of nature, and how attempts to overcome them can worsen the problem. Three Gorges opens as dams are coming under new scrutiny abroad from ecologists, as well as from economists who say some of these costly projects can survive only with subsidies.
Questions about the Yangtze River's changed environment are taking on added urgency as China grapples with a mounting water shortage. Across the country, millions of tons of raw sewage, industrial waste and fertilizer runoff have turned lakes into algae-covered cesspools. According to official statistics, more than half of China's major waterways are so polluted that fish are dying or water is unsafe for drinking or irrigation. More than 300 million people -- almost one-quarter of the population -- lack access to clean drinking water, the government says.
Making things worse, more than one-third of the country's 85,000 or so reservoirs have 'serious' structural problems, according to the official Xinhua news agency. This spring, a deputy minister of water resources called China's reservoirs 'time bombs' that could threaten the lives and property of those downstream. In 1975, a dam collapse in Henan province killed tens of thousands or more, an incident that was covered up until recently.
At the center of the water debate is Three Gorges, China's largest and most visible reservoir. The country's news media are beginning to cover problems with the dam. The government hasn't spoken publicly about issues with the dam and reservoir, but it has quietly rolled out an early warning system for landslides and is supporting research to map at-risk regions. Officials are pouring money into water-treatment plants and reinforcing about 2,250 kilometers of riverbanks.
'We thought of all the possible issues,' says environmental scientist Weng Lida, the former head of the Yangtze River Water Resources Protection Commission, a government agency tasked with protecting the environment and water resources of the river basin. He is now secretary general of the Yangtze River Forum, a coalition of the Chinese government and nongovernmental organizations that share research on the region's environment. 'But the problems are all more serious than we expected.'
The government agency that oversees the dam, the Changjiang Water Resources Committee, declined requests for an interview.
The changes can be seen here in Miaohe, where villagers have grown oranges from gnarled trees and farmed the area's steeply terraced rice paddies for generations. Miaohe's 100 or so residents narrowly avoided the mass relocations that accompanied the dam's construction, when 1.3 million people moved from their homes to make way for the reservoir.
This spring, villagers noticed a 200-meter-long crack, barely a centimeter thick, zigzagging across their paddies. Not long afterward, dam officials lowered reservoir levels to prepare for the summer flooding season.
After early May rains raised reservoir levels again, there were four landslides in five days not far from Miaohe village. As the earth shifted, villagers say they heard cracking as the timbers in their houses began to split. The government told them to evacuate.
An hour away in the county seat, Zigui City, officials are facing a new wave of relocations. About 100,000 people in the county were moved to make way for the reservoir, and now local officials are concerned they'll have to relocate many more. 'The changes have come faster than our plans,' said Cui Shaofeng, an official from the Zigui County resettlement office.
The 6,400-kilometer-long Yangtze is the third-longest river in the world, racing down from Tibetan glaciers, slicing massive valleys through the middle of China and passing fertile plains before its brown waters meet the sea. Along the way, the river passes the Three Gorges, a series of canyons that for centuries plagued sailors with swift currents and hidden rocks. Floods were a constant threat, claiming about 300,000 victims, by some estimates, in the last century alone.
China's leaders long dreamed of damming the Yangtze, in part to harness its power, but primarily to prevent catastrophic flooding. Modern China's founding father, Sun Yat-sen, proposed a dam in 1919. Mao Zedong, who believed nature could be shaped to man's purpose, wrote a poem about turning the treacherous Three Gorges into a navigable lake.
From the late 1950s, the government approved and then delayed construction of a dam here several times, hobbled by technical challenges. By the late 1980s, China also faced mounting charges that a dam and reservoir would not only force farmers to relocate en masse to cities, but also destroy some of China's most precious archeological sites and temples.
In April 1989, the government responded to criticism by announcing that it would delay a decision for at least five more years. But opponents were silenced in the aftermath of the Tiananmen Square crackdown a few months later. In 1992 scientists and engineers completed a final environmental feasibility study, and later that year the dam project was put to a vote before the National People's Congress. It passed. But nearly one-third of China's usually docile legislature voted 'No' or abstained, an unusual show of dissent.
Construction officially began in 1994, but controversy continued. Responding to pressure from human-rights groups, the U.S. government and the World Bank pulled support from the project. In an open letter in 2000, leading engineers in China, including some who had worked on the feasibility study, protested a decision to fill the reservoir faster than originally planned to maximize profit.
The first trouble came in June 2003, two weeks after the Yangtze River was impounded and the reservoir began to fill. While water levels rose, passing 90 meters and approaching 135 meters, the valley's slopes started eroding under the pressure of the water.
On July 14, a mountain on a tributary of the Three Gorges gave way, shearing a tongue of land about a kilometer wide and long and more than 18 meters thick. Thirteen farmers were swept to their deaths in the mud and debris. The wedge hit the water, sending a two-story-tall wave crashing over 20 boats, drowning 11 fishermen. Officials blamed the landslide on heavy rainfall. Geologists says a sudden change in water levels loosened rocks along the riverbanks.
With a final cost of at least $22 billion, the 180-meter tall dam was finished in May 2006. Once it is fully operational later this year, it will contain 19 trillion liters of water, equivalent to one-fifth of the fresh water consumed each year in the U.S. It will produce more than 18,000 megawatts of electricity, 20 times more than the Hoover Dam.
Mr. Weng, the environmental scientist, believes the dam was necessary to stop floods. Now, his biggest worry is the worsening quality of the reservoir's water. Phosphorus and nitrogen levels from industrial and fertilizer runoff have risen 10 times above levels a decade ago, according to the WWF report, which he co-edited.
The Three Gorges reservoir is also filling with sewage. Wastewater discharge has soared in the Yangtze River basin, more than doubling from 2000 to 2005, the WWF report says. The basin is home to 160 million people, including 30 million in what is now by some measures the world's largest municipality, Chongqing, about 640 kilometers upstream from the dam. In the decade ending in 2005, the Yangtze basin economy grew 12.6% a year on average -- a percentage point faster than the rest of the nation -- as it has switched from agriculture to heavy industry.
Scientists and government officials say many sewage plants were built to process waste before it hits the reservoir, but that some aren't connected to city drains. Zhou Wei, vice director of the department of reservoir management at the government's Three Gorges Project Construction Committee, acknowledges that sewage levels in the reservoir appear to be increasing. He says the government has given additional funds to make sure plants are running full-time.
From the beginning, engineers were also concerned about sedimentation. The Yangtze carries 500 million metric tons of silt into the gorges each year. Without a way to release most of this mud, the reservoir would silt up and possibly collapse. Government engineers created 23 sluice gates at the bottom of the dam to release turbid water during flood season, and they estimate the system will keep the reservoir at roughly 90% or more of its capacity for nearly a century. Some critics believe sedimentation is growing at a faster rate, which could eventually make the dam unable to contain a flood crest.
Downstream, fluctuating sediment levels pose yet a different problem. In water with little sediment, sunlight reaches deeper and nourishes the photosynthetic algae, which also feeds on sewage and fertilizer runoff, Mr. Weng says.
Mr. Zhou, the reservoir management vice director, says the dam isn't responsible for the blooms. Algae had turned out to be less of a concern than the Three Gorges committee had expected, he says, with only minor blooms in Yangtze tributaries. He didn't address downstream algae growth.
There are also concerns about whether the dam will fulfill its primary flood-control function. Weeks of torrential downpours in July created one of the biggest surges on the upper Yangtze -- the biggest crest since 1998, when flooding on the undammed river killed thousands downstream. Officials announced on Aug. 1 that the crest passed through the dam without incident, crediting the structure for taming it for the river's lower reaches.
Critics say that while the dam can handle flood surges, it may contribute to downstream flooding for an unforeseen reason. Past the narrow gorges where it enters central China's broad plains, the river traditionally slowed, and in some places centuries of sedimentation raised the riverbed above the surrounding countryside and is held back by dikes, as in the city of New Orleans. Water released by the dam runs faster, the WWF says, because the dams traps most of the silt. Lightened of its muddy load, the water courses out with more force and speed and threatens to gouge out the dikes.
Geologists, meanwhile, are focusing on landslides. The Three Gorges were formed as the river gradually sliced through rock 300 million to 70 million years ago. The gorges have a base of limestone but are layered in places with sandstone, shale and mudstone -- softer materials that are more likely to collapse. As dam officials raise and lower water levels in anticipation of floods, the soaking and huge pressure changes leave banks weakened and in danger of collapse.
'Slope instability is responsible for the most widespread natural hazard in the Three Gorges,' a team of scientists at the Imperial College London wrote earlier this year in the 'Quarterly Journal of Engineering Geology and Hydrogeology,' published by the Geological Society of London. They warned the problem is likely to get worse.
One of the authors looked at satellite readings of Zigui, Wushan and Badong counties, with a combined population of more than million people. In these areas, estimated geologist Ioannis Fourniadis of Imperial College London, 3% of slopes are actively falling and 7% are unstable for activities such as road-building. Another 15% were mostly stable. The rest were solid limestone, which he says pose extremely low risk.
Landslides can also trigger tsunamis, says Mr. Wang Fawu, a scientist at the Disaster Prevention Research Institute at Kyoto University, who has studied the gorges for decades. Narrow valleys could amplify a wave set off by falling rocks, sending a wall of water downriver. Such a flood occurred at northern Italy's Vaiont Dam in 1963, he says, killing 2,000 people.
A spokesman for China's Ministry of Land Resources blames this year's high incidence of landslides on heavy rainfalls since spring. He says the early-warning system has detected some major slides and that the government is training local people to recognize landslide warning signs.
A kilometer from Miaohe, where the gravel road that provides sole access to the village passes through a muddy tunnel, the villagers have set up temporary housing. Inside the tunnel, the farmers live in plastic lean-tos. Nearby the local government is creating a clearing where refugees will build their new homes. The site is an hour's walk from a simple river ferry.
The government is providing some money for new homes, but the villagers say it isn't enough. The farmers will be able to grow rice, oranges and tea here, but they complain that the land here isn't good for the crops. In a nod to the villagers' bleak future, the local government is providing families a dowry for their daughters, to encourage them to marry out.
'This all started happening right after they began damming the river,' says villager Han Qingxi, 52 years old, pausing for a moment from rebuilding his simple stone home. Nearby, giant backhoes level the mountainside. 'They say it's safer here,' he says.
THE MOST VAUNTED engineering marvel in China, the Three Gorges Dam project, is suffering from unforeseen problems including landslides and water pollution, raising new doubts about a project that has come to symbolize the country's effort to control its environment.
It was only a year ago that the massive Three Gorges Dam was completed, creating a reservoir on the Yangtze River some 640 kilometers long. Now, geologists say the trapped water's massive weight has begun to erode the Yangtze's steep shores at several spots. That, along with frequent fluctuations in water levels, has triggered a series of landslides and weakened the ground under places such as Miaohe, a village about 16 kilometers up the reservoir from the dam. Local officials worry that a whole mountainside here could collapse into the water, killing residents and threatening a vital shipping lane.
There are additional dangers. Chinese scientists say that as the dam blocks silt heading downstream, the Yangtze River estuary region, which includes Shanghai, is shrinking and salt water from the ocean is flowing further inland. A report this spring by the World Wildlife Federation said water flowing through the dam is now moving faster, damaging the downriver dikes that were built to prevent floods. Raw sewage and fertilizer runoff has fouled the reservoir, nourishing giant algae blooms and threatening downstream water supplies. Fluctuating reservoir levels have even been blamed for a bizarre plague of rats that farmers have been battling in central China's Hunan Province.
The emerging issues at Three Gorges illustrate this rapidly industrializing country's struggle against the constraints of nature, and how attempts to overcome them can worsen the problem. Three Gorges opens as dams are coming under new scrutiny abroad from ecologists, as well as from economists who say some of these costly projects can survive only with subsidies.
Questions about the Yangtze River's changed environment are taking on added urgency as China grapples with a mounting water shortage. Across the country, millions of tons of raw sewage, industrial waste and fertilizer runoff have turned lakes into algae-covered cesspools. According to official statistics, more than half of China's major waterways are so polluted that fish are dying or water is unsafe for drinking or irrigation. More than 300 million people -- almost one-quarter of the population -- lack access to clean drinking water, the government says.
Making things worse, more than one-third of the country's 85,000 or so reservoirs have 'serious' structural problems, according to the official Xinhua news agency. This spring, a deputy minister of water resources called China's reservoirs 'time bombs' that could threaten the lives and property of those downstream. In 1975, a dam collapse in Henan province killed tens of thousands or more, an incident that was covered up until recently.
At the center of the water debate is Three Gorges, China's largest and most visible reservoir. The country's news media are beginning to cover problems with the dam. The government hasn't spoken publicly about issues with the dam and reservoir, but it has quietly rolled out an early warning system for landslides and is supporting research to map at-risk regions. Officials are pouring money into water-treatment plants and reinforcing about 2,250 kilometers of riverbanks.
'We thought of all the possible issues,' says environmental scientist Weng Lida, the former head of the Yangtze River Water Resources Protection Commission, a government agency tasked with protecting the environment and water resources of the river basin. He is now secretary general of the Yangtze River Forum, a coalition of the Chinese government and nongovernmental organizations that share research on the region's environment. 'But the problems are all more serious than we expected.'
The government agency that oversees the dam, the Changjiang Water Resources Committee, declined requests for an interview.
The changes can be seen here in Miaohe, where villagers have grown oranges from gnarled trees and farmed the area's steeply terraced rice paddies for generations. Miaohe's 100 or so residents narrowly avoided the mass relocations that accompanied the dam's construction, when 1.3 million people moved from their homes to make way for the reservoir.
This spring, villagers noticed a 200-meter-long crack, barely a centimeter thick, zigzagging across their paddies. Not long afterward, dam officials lowered reservoir levels to prepare for the summer flooding season.
After early May rains raised reservoir levels again, there were four landslides in five days not far from Miaohe village. As the earth shifted, villagers say they heard cracking as the timbers in their houses began to split. The government told them to evacuate.
An hour away in the county seat, Zigui City, officials are facing a new wave of relocations. About 100,000 people in the county were moved to make way for the reservoir, and now local officials are concerned they'll have to relocate many more. 'The changes have come faster than our plans,' said Cui Shaofeng, an official from the Zigui County resettlement office.
The 6,400-kilometer-long Yangtze is the third-longest river in the world, racing down from Tibetan glaciers, slicing massive valleys through the middle of China and passing fertile plains before its brown waters meet the sea. Along the way, the river passes the Three Gorges, a series of canyons that for centuries plagued sailors with swift currents and hidden rocks. Floods were a constant threat, claiming about 300,000 victims, by some estimates, in the last century alone.
China's leaders long dreamed of damming the Yangtze, in part to harness its power, but primarily to prevent catastrophic flooding. Modern China's founding father, Sun Yat-sen, proposed a dam in 1919. Mao Zedong, who believed nature could be shaped to man's purpose, wrote a poem about turning the treacherous Three Gorges into a navigable lake.
From the late 1950s, the government approved and then delayed construction of a dam here several times, hobbled by technical challenges. By the late 1980s, China also faced mounting charges that a dam and reservoir would not only force farmers to relocate en masse to cities, but also destroy some of China's most precious archeological sites and temples.
In April 1989, the government responded to criticism by announcing that it would delay a decision for at least five more years. But opponents were silenced in the aftermath of the Tiananmen Square crackdown a few months later. In 1992 scientists and engineers completed a final environmental feasibility study, and later that year the dam project was put to a vote before the National People's Congress. It passed. But nearly one-third of China's usually docile legislature voted 'No' or abstained, an unusual show of dissent.
Construction officially began in 1994, but controversy continued. Responding to pressure from human-rights groups, the U.S. government and the World Bank pulled support from the project. In an open letter in 2000, leading engineers in China, including some who had worked on the feasibility study, protested a decision to fill the reservoir faster than originally planned to maximize profit.
The first trouble came in June 2003, two weeks after the Yangtze River was impounded and the reservoir began to fill. While water levels rose, passing 90 meters and approaching 135 meters, the valley's slopes started eroding under the pressure of the water.
On July 14, a mountain on a tributary of the Three Gorges gave way, shearing a tongue of land about a kilometer wide and long and more than 18 meters thick. Thirteen farmers were swept to their deaths in the mud and debris. The wedge hit the water, sending a two-story-tall wave crashing over 20 boats, drowning 11 fishermen. Officials blamed the landslide on heavy rainfall. Geologists says a sudden change in water levels loosened rocks along the riverbanks.
With a final cost of at least $22 billion, the 180-meter tall dam was finished in May 2006. Once it is fully operational later this year, it will contain 19 trillion liters of water, equivalent to one-fifth of the fresh water consumed each year in the U.S. It will produce more than 18,000 megawatts of electricity, 20 times more than the Hoover Dam.
Mr. Weng, the environmental scientist, believes the dam was necessary to stop floods. Now, his biggest worry is the worsening quality of the reservoir's water. Phosphorus and nitrogen levels from industrial and fertilizer runoff have risen 10 times above levels a decade ago, according to the WWF report, which he co-edited.
The Three Gorges reservoir is also filling with sewage. Wastewater discharge has soared in the Yangtze River basin, more than doubling from 2000 to 2005, the WWF report says. The basin is home to 160 million people, including 30 million in what is now by some measures the world's largest municipality, Chongqing, about 640 kilometers upstream from the dam. In the decade ending in 2005, the Yangtze basin economy grew 12.6% a year on average -- a percentage point faster than the rest of the nation -- as it has switched from agriculture to heavy industry.
Scientists and government officials say many sewage plants were built to process waste before it hits the reservoir, but that some aren't connected to city drains. Zhou Wei, vice director of the department of reservoir management at the government's Three Gorges Project Construction Committee, acknowledges that sewage levels in the reservoir appear to be increasing. He says the government has given additional funds to make sure plants are running full-time.
From the beginning, engineers were also concerned about sedimentation. The Yangtze carries 500 million metric tons of silt into the gorges each year. Without a way to release most of this mud, the reservoir would silt up and possibly collapse. Government engineers created 23 sluice gates at the bottom of the dam to release turbid water during flood season, and they estimate the system will keep the reservoir at roughly 90% or more of its capacity for nearly a century. Some critics believe sedimentation is growing at a faster rate, which could eventually make the dam unable to contain a flood crest.
Downstream, fluctuating sediment levels pose yet a different problem. In water with little sediment, sunlight reaches deeper and nourishes the photosynthetic algae, which also feeds on sewage and fertilizer runoff, Mr. Weng says.
Mr. Zhou, the reservoir management vice director, says the dam isn't responsible for the blooms. Algae had turned out to be less of a concern than the Three Gorges committee had expected, he says, with only minor blooms in Yangtze tributaries. He didn't address downstream algae growth.
There are also concerns about whether the dam will fulfill its primary flood-control function. Weeks of torrential downpours in July created one of the biggest surges on the upper Yangtze -- the biggest crest since 1998, when flooding on the undammed river killed thousands downstream. Officials announced on Aug. 1 that the crest passed through the dam without incident, crediting the structure for taming it for the river's lower reaches.
Critics say that while the dam can handle flood surges, it may contribute to downstream flooding for an unforeseen reason. Past the narrow gorges where it enters central China's broad plains, the river traditionally slowed, and in some places centuries of sedimentation raised the riverbed above the surrounding countryside and is held back by dikes, as in the city of New Orleans. Water released by the dam runs faster, the WWF says, because the dams traps most of the silt. Lightened of its muddy load, the water courses out with more force and speed and threatens to gouge out the dikes.
Geologists, meanwhile, are focusing on landslides. The Three Gorges were formed as the river gradually sliced through rock 300 million to 70 million years ago. The gorges have a base of limestone but are layered in places with sandstone, shale and mudstone -- softer materials that are more likely to collapse. As dam officials raise and lower water levels in anticipation of floods, the soaking and huge pressure changes leave banks weakened and in danger of collapse.
'Slope instability is responsible for the most widespread natural hazard in the Three Gorges,' a team of scientists at the Imperial College London wrote earlier this year in the 'Quarterly Journal of Engineering Geology and Hydrogeology,' published by the Geological Society of London. They warned the problem is likely to get worse.
One of the authors looked at satellite readings of Zigui, Wushan and Badong counties, with a combined population of more than million people. In these areas, estimated geologist Ioannis Fourniadis of Imperial College London, 3% of slopes are actively falling and 7% are unstable for activities such as road-building. Another 15% were mostly stable. The rest were solid limestone, which he says pose extremely low risk.
Landslides can also trigger tsunamis, says Mr. Wang Fawu, a scientist at the Disaster Prevention Research Institute at Kyoto University, who has studied the gorges for decades. Narrow valleys could amplify a wave set off by falling rocks, sending a wall of water downriver. Such a flood occurred at northern Italy's Vaiont Dam in 1963, he says, killing 2,000 people.
A spokesman for China's Ministry of Land Resources blames this year's high incidence of landslides on heavy rainfalls since spring. He says the early-warning system has detected some major slides and that the government is training local people to recognize landslide warning signs.
A kilometer from Miaohe, where the gravel road that provides sole access to the village passes through a muddy tunnel, the villagers have set up temporary housing. Inside the tunnel, the farmers live in plastic lean-tos. Nearby the local government is creating a clearing where refugees will build their new homes. The site is an hour's walk from a simple river ferry.
The government is providing some money for new homes, but the villagers say it isn't enough. The farmers will be able to grow rice, oranges and tea here, but they complain that the land here isn't good for the crops. In a nod to the villagers' bleak future, the local government is providing families a dowry for their daughters, to encourage them to marry out.
'This all started happening right after they began damming the river,' says villager Han Qingxi, 52 years old, pausing for a moment from rebuilding his simple stone home. Nearby, giant backhoes level the mountainside. 'They say it's safer here,' he says.
Labels: Three Gorges Dam
¶ 10:23 AM
