Yangtze Tsunami

Steve's picture

Have you ever heard of China’s Three Gorges Dam? That’s that mega project intended to control the Yangtze River.  At 1.3 miles long, 610 feet high, and possessing the hydroelectric capacity of eleven Hoover Dams, the thing is sometimes called “China’s Other Great Wall”.

Because of the Yangtze’s low gradient, the Three Gorges Dam will back up the River for 360 miles.  1.3 million people are to be displaced by rising waters.  Most of these folks already have, or soon will, relocate to “new towns” sited and built by the government on nearby hills.

As often the case with reservoirs, impounded water increases the fluid, or pore, pressure in adjacent rock formations.  Increased pore pressure acts to “lubricate” existing fractures in the rock.  Lubrication can induce earthquakes and accelerate piping of fluids around or through the dam.  The former certainly generate unease in close by residents, while the latter has been known to lead to complete dam failure (See my blog “Teton Trouble”).

Another product of fracture lubrication are landslides.  As you might suppose from the name, the banks of the Yangtze in Three Gorges are astonishingly steep.  Landslides in the Region were not unusual even prior to dam building.  The Chinese take reservoir induced landslides very seriously because some of those “new towns” have been recently discovered to be sitting on fossil landslide debris. Moreover, highly visible landslides directly into the Yangtze River pose hazards to property, transportation,  tourist trade and public perception. You can imagine that the “L word” is politically delicate.

In November, 2008 a significant rock slip struck Wu Gorge, 120 km upriver from the Dam.  Losses were minimal, but the event highlighted some of the issues associated with the “L word”.  I have made this YouTube movie detailing the event, together with several computer simulations of the slide and tsunami.

Like all major water projects, Three Gorges has potential for disaster.  Let’s hope that the Dam lasts as long as “China’s Other Great Wall”.

Steven N. Ward     Santa Cruz

Comments

pbrundle's picture

I can see how rising water could lubricate fractures and make it easier for earthquakes to happen, but why would the Chinese government to build a dam in an earthquake-prone area?

HarryWilliams's picture

It’s really shocking why the government took such weird decisions; the safety cautions are very less. I heard about the lake through popular assignmentman service and the project is very dangerous to be built. Hope the project could be stopped and implement any other behalf of this.

Connie2256's picture

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elamoxon's picture

The Chinese consider store prompted avalanches important on the grounds that some of those "new towns" have been as of late found to sit on fossil avalanche trash. Besides, profoundly noticeable avalanches specifically into the Yangtze River posture risks to property, transportation, traveler exchange and open recognition. You can try http://www.simonsholidays.uk/kerala-packages/ Kerala tour with houseboat stay.

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