Gravity dam

[1][2] Gravity dams generally require stiff rock foundations of high bearing strength (slightly weathered to fresh), although in rare cases, they have been built on soil.

The main advantage to gravity dams over embankments is the scour-resistance of concrete, which protects against damage from minor over-topping flows.

A disadvantage of gravity dams is that their large concrete structures are susceptible to destabilising uplift pressures relative to the surrounding soil.

Gravity dams are built by first cutting away a large part of the land in one section of a river, allowing water to fill the space and be stored.

Sometimes the soil is sufficient to achieve these goals; however, other times it requires conditioning by adding support rocks which will bolster the weight of the dam and water.