arch dam

noun

1. a dam resisting the pressure of impounded water by an arch principle, especially a dam having in plan the form of a single arch abutted by natural rock formations.

arch dam

noun

1. a dam that is curved in the horizontal plane and usually built of concrete, in which the horizontal thrust is taken by abutments in the sides of a valley. Arch dams must be built on solid rock, as a yielding material would cause a failure