The following article from Chinadialogue.net highlights some of the key issues with the construction of Three Gorges Dam, as the project is nearing its completion. The author emphasizes on China conducting a thorough environmental impact assessments after the project is over.
- China completed the highly complex, challenging construction project ahead of schedule, which is rare in the international hydropower sector. Technically, the Three Gorges Dam is a masterpiece of Chinese engineering. The government insists that with a cost of US$27.2 billion, the project was built within budget. Others claim that many costs do not appear in the official calculations, and that the project may cost up to $88 billion.
- The hydropower project on the Yangtze River substitutes the burning of at least 30 million tonnes of coal every year, which is more than 1% of China’s total coal consumption. However, the Three Gorges Dam was not the only option for replacing coal. During the period from 2001 to 2005, the energy efficiency of the Chinese economy dropped overall. According to Douglas Ogden of the Energy Foundation, it would have been “cheaper, cleaner and more productive for China to have invested in energy efficiency” rather than in new power plants.
- The dam has displaced more than 1.24 million people, and more people will need to be displaced to avoid an environmental disaster in the reservoir area. When I visited the Yangtze Valley this summer, many people complained that compensation payments had been diverted into the pockets of local officials, and were not sufficient to pay for the new apartments. Citizens who protested against such corruption were frequently beaten up. The government was not able to fulfill its original promise to provide jobs and replacement land to most resettlers. Now that the project is complete, some areas have overcome the trauma of displacement, while others seem to be caught in a cycle of poverty and desperation.
- The Three Gorges Dam is a massive intervention into the Yangtze’s ecosystem. Now that it has been converted into a stagnant water body, the river has lost the ability to clean itself. Pollution from the submerged areas and the dirty industries along the shores are causing frequent toxic algae blooms. Important fish species are threatened with extinction, and commercial fisheries in the Yangtze and off the river’s mouth have plummeted. In September 2007, senior government officials warned that the project could turn into an environmental “catastrophe” if drastic measures were not taken.
- The water level of the Three Gorges reservoir fluctuates between 145 and 175 metres every year. This has already destabilised the slopes of the Yangtze Valley, and has created serious risks of erosion and landslides. According to Caijing magazine, erosion affects slightly more than half the reservoir area, and 178 kilometres of riverbanks are at risk of collapsing. The project authorities had not predicted such a serious threat to the region.
- Since most of the silt load from the Yangtze’s upper and middle reaches is now deposited in the reservoir, the downstream regions are being starved of sediment. Up to four square kilometres of coastal wetlands are eroded every year, and seawater is intruding up the Yangtze. Some scientists even suggest that changes in the Yangtze’s nutrient load are responsible for the sudden explosion of giant jellyfish populations which hamper fisheries off the coast of Japan. While there are no in-depth studies on this phenomenon, the discussion illustrates that the ecological impacts of large dams are often too wide-ranging and complex to be predicted or controlled.
- Periodic floods have taken the lives of hundred thousands of people in the Yangtze Valley. The Three Gorges reservoir has created a buffer which mitigates these flood risks. On the other hand, the river’s silt-free water is now scouring the banks downstream of the dam, which undermines these benefits. The dam also increases the exposure of Shanghai to typhoons by eroding the coastline, and creates seismic risks in the Yangtze Valley. It is difficult to balance these risks with the increased flood protection which the dam may offer in the lower Yangtze Valley.
- Earlier this month, the project authorities could not raise the water level in the reservoir to 175 metres as planned. They were surprised by the drought in the lower Yangtze Valley and, some observers say, needed to protect the banks of the reservoir from further landslides. The incident suggests that the interests of electricity generation, flood protection and environmental mitigation will continue to collide in the operation of the reservoir.