Some notes on the Yangtze/Three Gorges Dam Project
    Destined to perhaps become yet another Wonder of the Modern World the recently completed "Three Gorges Dam Project" on the Yangtze (or Chang Jiang) river in China, still has many "ifs" and "buts" hanging over it.
    The scale of the project is difficult to comprehend; it is the largest civil engineering project the Chinese have engaged upon since the construction of the Great Wall many centuries ago and is very much a source of national pride and prestige. It HAS to succeed. But will it?
    The idea of a dam across the Yangtze was first mooted earlier in the last century, primarily to alleviate the regular, devastating flooding in the lower reaches of the river. Television pictures of the last severe flood in 1998 may come to mind when thousands of people lost their lives and billions of dollars of damage was done. So, after some nine years of construction, the project was finally completed in 2003. It is 2335m long (almost a mile and a half), some 185m (607ft) high and will house 26 giant turbines each weighing some 400 tons which will, between them, produce 18,200 megawatts - almost three times the output of the U.S. Grand Coulee tam, some 20% of China's electrical power needs and the equivalent of 18 nuclear power plants. Most of this will be fed, initially, to Shanghai and the East China Sea regions rather than the immediate locality. There is a 5-stage lock system capable of taking ships much larger than those that used to navigate the Yangtze. The economics of the project, as presented, are olindingly simple. The construction costs will be saved within ten years or so because of the prevention of flood damage. The sale of the generated power will then be a continual source of income, easily exceeding maintenance costs. Voila!
    Note the height of the dam - 185 metres - and just think for a moment of the implications. By 2009 the water level in the Yangtze behind the dam will have risen by 175 metres (575 feet) and the reservoir that is formed will back up some 375 miles to Chongqing. In other words a huge inland sea will have been created and the fabled scenery of the Yangtze Gorges will be changed forever.
    Also changing forever are the lives of the 1.3 million people who are being displaced by the rising waters. Along the river bank there are many cities, towns and villages and as one travels up the river there are numerous markers sited high on its banks which indicate the eventual water level. Many of these settlements are being submerged by the slowly rising waters and plans have been underway for some time to resettle the unfortunate citizens. A number of them have been relocated to Shanghai (where no one speaks their dialect), many new apartment tower blocks are being built higher up on the slopes of the river bank, farmers working the fertile soil of the river bank are being offered land higher up the river's mountainous slopes, which inevitably happens to be stony and barren. Unused to possessing large sums of money the $3000 resettlement grants given to families to help them relocate are being squandered on non-essentials. The official line is that the families are happy to move to modern, new apartments but this disregards the strong feelings that many have for their existing homes, homes that they may have had for many generations and where their forebears and ancestors have lived and died.
    To discourage any of the unfortunate citizens from returning it is also official policy to demolish all of the buildings below the eventual higher water level. This has the effect of creating scenes of total devastation along the waterfronts, comparable to an earthquake or a war. It also creates serious environmental problems of course. Sewage systems, where they exist at all, will be submerged. Industrial sites on ground contaminated with a lethal cocktail of chemicals will also be submerged. And remember, there will no longer be swiftly flowing river currents to wash these contaminants away.
    The resulting absence of strong river currents also has an important bearing on another feature of the Yangtze - silt. Like its sister river, the Yellow River to the north, the Yangtze carries enormous quantities of silt from its upper reaches and its colour is a consistent murky brown. What will happen to all of this silt which will still continue to be added to that already there? Some say "No problem! The new waters will be sufficiently deep for it to be no hindrance to navigation. If there is a problem then we'll dredge it." Others say "What if the silt slowly piles up against the dam? Will it interfere with the efficient operation of the turbines? Will it become a threat to the dam itself?" The real answer - no one really knows.
    The present course of the 3964 mile long Yangtze river, from the Tibetan plateau to the East China Sea, has been dictated by geological earth movements. (Many millions of years ago, before India collided with Tibet, it used to flow westwards towards the Mediterranean Sea.) Geologists have decided that the site of the dam at Sandouping, a narrow point of the Xiling Gorge to be the most suitable - although the area is still possibly liable to the very occasional small earth movement! There has also been some concern expressed about the sheer weight of the structure on the underlying ground. Some cracks have already been observed in the structure although they are apparently purely "cosmetic" and have been repaired. Comments have also been passed on the construction methods employed - the concrete not being poured continuously was one such. It is also understood that many of the thousands-strong construction force are army conscripts. The consequences of the dam suffering a catastrophic failure are, of course, too horrific to contemplate. It might be mentioned that several other smaller dams, built on other rivers in China in recent years, have not been overly successful - hopefully not a portent for this one.
    Other consequences of the creation of this new inland sea are the loss of many very important archaeological sites, a number of which have only recently been discovered. Many of them date from before 2000BC. Where funds permit there is intense activity on some of these sites to rescue something before the waters inexorably rise and they are covered over for ever.
    So, "Chang Jiang", you have some interesting times ahead of you. Let us hope that some of them, at least, are good and that the thousands of families displaced by this modern wonder also gain some good from their sacrifices.

A.G.