Types of Dams
Dams can be grouped according to the type of material of which they are constructed as follows; concrete dams are further grouped according to how they achieve their strength and stability.
FILL (EMBANKMENT) DAMS
- Concrete Gravity Dams
- Concrete Arch Dams
- Concrete Buttress Dams
- Earth Dams
- Earth and Rock Fill Dams
- Concrete Faced Rock Fill Dams
Concrete Gravity Dams rely on the weight of the concrete of which they are built to resist the forces (gravity, water pressure, earthquake) to which they are subjected.
Concrete Arch Dams and Buttress Dams can be built using a smaller amount of concrete than that required for a Gravity Dam and, as a result, are cheaper to build. This is possible because Arch and Buttress Dams are designed to transfer some of the loads (forces) on them to the foundation on which they are built ie the strength of the foundation is used to help resist the loads which could not be resisted simply by the weight of the dam wall alone. In all cases the impermeable membrane of concrete dams is the whole dam wall.
Fill or Embankment Dams are grouped according to the material of which they are constructed which, in turn, relates to the type of impermeable membrane used.
Earth Dams are built of homogeneous, impermeable earth material so that the impermeable membrane is the whole dam wall.
Earth and Rock Fill Dams have a relatively narrow, impermeable earth or clay core inside the dam but most of the dam is constructed of permeable rock fill which, by itself, would be incapable of retaining water. The impermeable membrane in these dams is the clay core.
Concrete Faced Rock Fill Dams are constructed of permeable rock fill, the impermeable membrane being a concrete slab constructed on the upstream face of the dam wall. This type of dam has become increasingly popular over the last 25 years or so. A recent example is the proposed 205 m high Bakun Dam in Malaysia, originally put on hold due to the Asian financial crisis.
Three Australian concrete faced rock fill dams (CFRD) built in 1970-71 (Pindari, Kangaroo Creek and Cethana) played a significant role in the development of the CFRD type of dam design.
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