Let's see if I can get the numbers on the three gorges project.
The capacity of the reservoir is 39.3 cubic km. The area is 1,000,000 sq kilometers (if I read wiki correctly there). This is full capacity, which is not normally used since they need a flood buffer. Add to that the weight of the dam, locks, etc.
But I don't think the problem is going to be the actual pressure by m^2. It might have more to do with the distribution of weight by the dam wall (which, by the way, is an incredible feat of engineering) or the water seeping into the surrounding area.
I also found that the BBC has picked up on that scarecrow:
http://news.bbc.co.uk/2/hi/science/nature/1974736.stm
This of course ignores that there have been huge quakes in the area long before the dam was built and that the reservoir isn't even filled yet...
Any thoughts?
