Question

why do dams have broad base

Answer 1

Because if the base will be strong...then the whole dam will be able to beer the water pressure....thank u

Answer 2

the reason is that the pressure exerted by a liquid increases with its depth. Thus as the depth increases, more and more pressure is exerted by the wateron the wall of the dam. A thicker wall is required to withstand greater pressure therefore the thickness of the dam increases towards the bottom.