gravity dam

Its huge mass resists the thrust of the water to prevent it from overturning or sliding; this type of dam is usually used to hold back large volumes of water.

cross section of a gravity dam

cut-off trench

Watertight structure that extends the foundations of the dam into the ground; it limits leakage and infiltration under the dam.

reservoir

Basin formed by the construction of a dam; it holds back a very large volume of water so that the flow rate can be controlled.

afterbay

Area of the watercourse where water is discharged after passing through the turbines.

downstream face

Usually sloping dam face on the afterbay side.

upstream face

Dam face on the reservoir side.

top of dam

Upper part of the dam that usually contains a roadway.