Tallowa Dam, completed in 1976, is a

concrete gravity dam Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...

with central overflow

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure th ...

, located on the Shoalhaven River, downstream from the river's confluence with the Kangaroo River. The dam wall of is high and in length. At 100% capacity, the dam wall holds back approximately and creates the impounded reservoir of Lake Yarrunga that has a surface area of , drawn from a catchment area of . The spillway has a discharge capacity of . The 'full operating storage' for Tallowa Dam refers only to the amount of water in the dam that is available to be transferred to Sydney and the Illawarra. When full, the dam can hold approximately . is available to be transferred to the Sydney water supply. Other water from Tallowa Dam is provided to

Shoalhaven City Council The City of Shoalhaven is a local government area in the south-eastern coastal region of New South Wales, Australia. The area is about south of Sydney. The Princes Highway passes through the area, and the South Coast railway line traverses t ...

for supply to local communities. Water is also released from the dam as environmental flows for the Shoalhaven River. The construction of a large barrier across the river has meant that the means of travel for fish has been completely confounded. There was no longer any means for the fish to get to their spawning areas further upstream. An innovative fish lift was constructed in 2009 to allow the fish to be collected and transferred over the dam wall.

See also

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Further reading