Three Gorges Extravaganza

Time to pack again. Sadly our last day on the cruise ship. After another scrumptious buffet breakfast we left the ship, traipsed through the narrow cast iron doorways and corridors of the lower decks of the ship adjacent to ours and surfaced on the dock. A single train carriage of sorts, inclined at about 30 degrees, transported us to the shore, where we negotiated a hoard of vendors, who rapidly descended on us, eager to sell us books and souvenirs before we boarded our bus for the Three Gorges Dam. The sun was scorching in the humidity of the day.

The tour was included as part of our Yangtze cruise package. Lily, our young guide for the morning, enlightened us about the Three Gorges Dam Project, as amazing as it is controversial. Campbell, the river-guide on our cruise, had similarly given us a background talk on the dam a few days previously.

Dam Amazing but Dam Controversial

The Dam Harbours Controversy

The dam project harbours not only the waters of the Yangtze but also considerable controversy.

The Good

Proponents of the dam argue for benefits in terms of saving lives through controlling the water level and reducing the impact of flooding. Historical records list 214 floods over the past 2200 years. The Yangtze River has notoriously claimed the lives of 300,000 people in the floods of 1871; 145,000 in 1931 and 142,000 in the floods of 1935. And countless millions of lives have been impacted.

A further benefit is the ability to harness the untapped energy that lies within the river. The Three Gorges Project will become the largest power plant in the world. Currently 70% of China’s energy is sourced from coal. The hydroelectric energy generated by the dam’s turbines will contribute to a reduction in coal consumption.

Other benefits include a reduction in the cost of navigating the river for commercial vessels and facilitating transfer of water to Beijing as part of the South-North water transfer initiative. The project is, not least of all, a matter of national pride being the lergest water conservancy project ever undertaken by man.

The Bad

Detractors have raised concerns about the human and environmental impact of the dam.

The rising waters have forced the relocation of at least 1.3 million people to higher ground. Families will lose the land they’ve inhabited for generations. This was evident on our bus trip from the cruise ship to the dam, for we passed through “New” Zi Gui, a relocated town perched in the shadow of the dam itself. The official line is that the young people feel positively about the move, giving them a chance to improve their quality of life by moving to newly built cities with more spacious and luxurious accommodation at subsidised prices. The older generations, however, are less optimistic and rue the loss of their land and way of life. There may also be changes to temperature and precipitation in the vicinity of the dam, further impacting on the delicate ecosystem.

Endangered species living in the maters of the Yangtze may be affected. These include the Chinese Sturgeon, the Baiji Dolphin, the Finless Porpise and the Yangtze Alligator. The Baiji Dolphin is a freshwater dolphin and there are less than 100 remaining in the wild. In fact, in a recent search was unable to locate the dolphin and it may already be extinct.

Sedimentation may contribute to flooding itself. Accumulation of silt at the dam site will further raise the water level unless it is cleared periodically. Passage of silt through the turbine generators may also prematurely wear out the turbines. Sluice gates have been incorporated into the dam design to mitigate the downstream accumulation of silt and its deleterious effects. Further upstream, however, dredging would be required to remove the silt and dredging is an expensive undertaking.

Other potential problems include the dam becoming either a target for terrorist attack or a source of an earthquake.

The Raw Facts

Timeline

Construction officially began in 1994 and is due for completion in 2009, the project having been conceived by Sun Yat Sen in 1918.

Cost

The total investment is approximately $US 25 billion, equivalent to 209.3 billion Chinese Yuan.

Dam Placement

There were three major reasons for choosing to construct the dam in the Xiling Gorge (the third of the Three Gorges) at Sandouping.

1. This section of Xiling Gorge comprises granite rather than sandstone or limestone found elsewhere. A strong foundation is of critical importance.
2. This was the site of an island within the river itself. The island was a third of the way across the river, facilitating closure of segments of the river for construction purposes.
3. It was decided to preserve a small farming village located at Sandouping, which is currently nestled behind a sturdy dyke.

Dam Workers

Currently 5,000 workers on site. At the peak of construction 28,000 workers were on site. In the final stages only 2,000 workers will be required.

Water Level

Prior to construction the water level was 75m above sea level, while following completion the maximum level will be 175m with the dam height at 185m. The current maximum level is 154m, however, during flood season (July to September) it is lowered to 147m to accommodate surges of water and obviate the risk of downstream flooding. A watermark, visible throughout Xiling and the lesser three gorges, attests to this preemptive lowering of the water level. A reservoir, 600 km in length and with a cpacity of 39.9 billion cubic metres, will be created extending as far as Chongqing.

Dam Wall

The dam wall is 18m wide at the top and 130m wide at the riverbed. It is 2335m long.

“Seven Degrees Dam”

This alternative name for the dam is derived from the fact that the cement used in construction was allowed to set at 7°C. Slowing the rate at which the cement hardens, will reduce the chance of cracks developing. The constant temperature of 7°C was achieved by embedding large pipes within the cement and running iced water through the pipes in summer and warm water in winter. The lifespan of the concrete is predicted to be at least 200 years.

Turbines

There are 14 hydroelectric generators to the left of the spillway and 12 to the right. All of the left turbines are in place while only 2 of those on the right are in place. Eventually another 6 will be added for a total of 32 generators. Annual power generating capacity is from 18,200 - 23,000 megawatts, or 85-100 billion kilowatt hours, which is equivalent to the output from approximately 15 nuclear power plants. The first generator started to produce power in 2003 when the body of the dam was completed.

Ship Elevator

Ship traffic has to be managed at the dam. This is achieved currently via a two lane, five stage ship lock which takes several hours to negotiate. This is the only option for large vessels, and it’s free of charge. Small vessels, less than 3000 tonnes, will have another option by 2012. There will be an elevator to transfer the vessel from the higher upstream waters to the lower downstream waters in under 40 minutes. However, ship captains will have to pay for the privilege.

New Roads

Twentt-eight kilometres of manicured roads were built around the dam site, linking the project to the nearby city of Yichang.

Our Impressions

We were left with an indelible impression of the amazing capacity for mankind to transform his environment. The Dam is without doubt a remarkable achievement of planning, cooperation and engineering. There appears to be much benefit to be gained from the project in terms of lives saved from the ravages of flooding and the capacity for hydroelectric power generation. Yet, such optimism is tempered by the impact of the construction on the lives of millions of Chinese who have carved out their livelihoods on the Yangtze, and the environmental burden that will be borne. Only time will tell if it has been worthwhile.

We returned to the ship for a final buffet lunch – hot chips and make-your-own hamburgers – before final disembarkation and the bus trip to Yichang, our haven for the night.