Monday, 7 May 2012

Dan Sharpe: Recent News - Three Gorges Dam

Dan Sharpe, regular GfGD Columnist, writes...

Three Gorges Dam
A subject of many an A-level geography essay, the construction of the Three Gorges Dam was completed in 2006 and the 181m high dam is thought to have cost nearly £25 billion to build. It is the second largest producing dam with regards to electricity output (behind the Itaipu Dam on the border between Brazil and Paraguay) but this has come at a serious cost, and not just financially. About 1.4 million people have already been removed from their homes as the surrounding valley was flooded, and the Chinese Ministry of Land Resources have just announced that a further 100,000 people are to be evacuated due to safety issues.

The dam caused an area of over 600 square kilometers to flood and finally filled up to this maximum in 2010. Since then the number of geological disasters has increased dramatically. Landslips and rockfalls have led to the identification of 5,386 hazardous sites with banks already collapsing in hundreds of places. The unstable nature of the banks is caused by the huge seasonal variation in water level and it is this variation that is causing thousands more to be moved from their homes.

Submerged Cities:
Photos from1987 (bottom) and 2006 (top)
The controversial dam was the dream of revolutionary leader Mao Zedong and has submerged 13 cities, 140 towns and over 1,300 villages - staggering figures that have frequently been frowned upon by many nations (and geography students of course). More recently, a report published by the environmental group Probe International suggested that the entire upper Yangtze (where 20 dams are located, including the Three Gorges) is at risk from a catastrophic collapse of these man-made structures. The idea focused around the seismic activity in the area and the theory that a failure of one dam could cause a cascade of water collapsing further dams, which in a heavily populated area is clearly a significant problem.

The Three Gorges Dam is perhaps the last example of China’s historical dictatorship, a construction that typifies the ‘greater good’ mentality with little care for the collateral damage to local people. Now, in a westernising government, this fiercely growing nation has admitted problems regarding this structure. They have conceded that they have not done enough to ensure a similar quality of life for those forced to move, and many families are beginning to move back to the banks of the reservoir increasing the fatality risk from natural disasters. Further to this, there is suggestion that the reservoir increases the risk of earthquakes in the area, and has completely changed the ecology of the river even driving the Yangtze River Dolphin to extinction.

The long term goal was to provide a sustainable source of energy, which has certainly been fulfilled, as well as controlling damaging floods that used to regularly hit the area. In 2010 for example, the South China Floods caused the reservoir to rise by 3m in less than 24 hours. Due to the control of the dam, the outflow of water was reduced from 70,000m3/s in to the reservoir to just 40,000m3/s out, effectively reducing the impacts of serious flooding on the middle and lower river.

The Three Gorges Dam is a difficult issue. On one hand it is fantastically resourceful and very good at controlling floods; however it has ruined hundreds of thousands of lives. People have been forced to move into lower standard housing in poor areas with no prospects of work, and the government has done little to support them. This project was an example of what we can achieve with hydro-electric power, but due to the political situation in China at the time, it cannot be considered fully sustainable as so many citizens were displaced. As China are beginning to accept the problems with the dam, hopefully quality of life will increase for those who once suffered and the safety of the area improved. Still, with increasing evidence for the possibility of a catastrophic failure due to seismic activity, it may not be the last negative we hear about the geography students’ favourite case study.