Overview
Arch-gravity dams are massive dams of concrete that resist the thrust of water by their weight pushing down using the force of gravity. A gravity dam is constructed so that the dam's massive weight resists the pressure of the water against it.
At the same time an arch-gravity dam incorporates the arch's curved design that is so effective in deflecting the water in narrow, rocky locations where the gorge's side are of hard rock and the water is forced into a narrow channel. Therefore the span needed for the dam is narrow; the dam's curved design effectively holds back the water in the reservoir using a lesser amount of construction material.
When properly situated on an appropriate site, the arch-gravity dam, combining the load resisting qualities of both a gravity dam and an arch dam, inspires the most confidence in the public at large because of its appearance of massive permanence. However, curving a gravity dam may make it look stronger, but some of this effect may be psychological factors in operation in making a choice of dam style.
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