One of the limiting factors to building a dam is that the rock under the dam is softer than the rock on either side. That is why there is a gorge there in the first place.
The 3 gorges dam was built there is because Mao had a dream of a dam being built there. The designers warned about the structural issues from a dam that high with that much of an impoundment area.
The water behind the 3 gorges dam actually affects the rotation of the earth. It is very small but it is measurable.
WWG1WGA
Garde la Foi, mes amis! Nous nous sommes les sauveurs de la République! Maintenant et Toujours!
(Keep the Faith, my friends! We are the saviors of the Republic! Now and Forever!)
LonePalm, le Républicain du verre cassé (The Broken Glass Republican)