Kids’ Guide to Dams

What are dams and how do they work?


There are many different types of dam and they all work in different ways and do different jobs. Take a look…

Arch dam

This is best for narrow rocky ravines with steep walls strong enough to support the structure They’re made from solid concrete that curve upstream, forming an arch.

The pressure from the water is distributed evenly which means no point is likely to break, similar to an arch bridge. The weight of the dam pushes it into the ground, helping to reinforce it too.

Dam 1

Buttress dam

Buttress dams are used when the surrounding rock is not strong enough to provide a solid foundation.

A series of solid concrete buttresses – kind of like beams – lined along the downstream face of the dam provide the strength needed to hold it in place. Buttresses add weight to the structure, pushing towards the ground and anchoring the dam even further. Since most of the support comes from the buttresses, the dam wall can either be flat or curved.

Buttress Dam

Embankment dam

Made from a bank of earth, these dams rely on their intense weight and sloped shape to hold the water back.

There may be an impervious layer of concrete, plastic or other material on the upstream face if the particle sizes in the earth are big enough for water to seep through. Earth-filled dams can be made completely from one type of material, but may need a layer that collects and drains seep-water to ensure the structure stays intact.

Dam 3


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