Originally Posted by
nomorehelosforme
Crab, I started looking at the mathematics of this and gave up! That aside, some good pictures and videos on the Daily Mail
Think in terms of pressure, not weight. The extent of the reservoir behind the dam wall doesn't affect the load on the wall at all; it could go back a hundred miles or it could be a narrow canal between two parallel dam walls, but the pressure at the surface of the dam depends only on the depth, and the force on the wall is the integral of pressure x area over the immersed surface.