Embankment Dams
These rely on a large mass of cheap materials such as rock, gravels, earth or clay to hold back the water. Their shape usually reflects the natural settling angle of the material used to make them. Concrete, bitumen or clay are used to prevent water seeping through the dam.
Concrete Faced Rockfill Dams
Hydro Tasmania specialised in the construction of these types of dams. The largest in the State is the Reece Dam. It is 122 metres high and contains more than 2.6 million cubic metres of fill. Locally available, good quality rock material was transported and compacted using heavy machinery. The dam was waterproofed using a thin layer of cncrete on the upstream face. Other dams of a similar type include Cethan, Wilmot, Paloona, Serpentine, Murchison, Mackintosh, Bastyan and Crotty. The Scotts Peak Dam has a bituminous concrete face and the Mackenzie Dam has a bitument face.
 Blackline represents Concrete and Bitumen Face |
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Clay or Earth - Cored Rockfill Dams
These differ from concrete-faced dams in their method of waterproofing. Instead of using thin concrete or bitument faces they have a central core of clay or other fine-grained material. The water penetrates the upstream side of the dam but is prevented from flowing through the clay core. The Hydro has built a number of these dams - particularly during he 1950s and 60s. Examples include Rowallan, Parangana, Echo, Bradys, Binney, Wayatinah and the third Miena Dam.
 Central clay core (orange) is the method of water-proofing |
 Rowallan Dam in Tasmania's north-west. An intregal part of the Mersey Forth Scheme |
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