geo.wikisort.org - Reservoir

Tallowa Dam, completed in 1976, is a concrete gravity dam with central overflow spillway, located on the Shoalhaven River, downstream from the river's confluence with the Kangaroo River. The dam wall of 325 cubic metres (11,500 cu ft) is 43 metres (141 ft) high and 528 metres (1,732 ft) in length. At 100% capacity, the dam wall holds back approximately 85,500 megalitres (3,020×10^⁶ cu ft) and creates the impounded reservoir of Lake Yarrunga that has a surface area of 831 hectares (2,050 acres), drawn from a catchment area of 5,750 square kilometres (2,220 sq mi). The spillway has a discharge capacity of 27,600 cubic metres per second (970,000 cu ft/s).[2]

Tallowa Dam
The Tallowa Dam spillway, 2010
Country	Australia
Location	Shoalhaven
Coordinates	34°46′11″S 150°18′30″E
Purpose	water supply
Status	Operational
Construction began	1972[1]
Opening date	1976
Construction cost	$11,250,000
Dam and spillways
Type of dam	Gravity dam
Impounds	Shoalhaven River
Height	43 m (141 ft)
Length	518 m (1,699 ft)
Dam volume	325 m3 (11,500 cu ft)
Spillways	1
Spillway type	Central overflow
Spillway capacity	27,600 m3/s (970,000 cu ft/s)
Reservoir
Creates	Lake Yarrunga
Total capacity	90,000 ML (3,200×10^6 cu ft)
Catchment area	5,750 km2 (2,220 sq mi)
Surface area	831 ha (2,050 acres)
Website Visit Tallowa Dam at waternsw.com.au

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 90,000 megalitres (3,200×10^⁶ cu ft). 21,800 megalitres (770×10^⁶ cu ft) is available to be transferred to the Sydney water supply.[3] Other water from Tallowa Dam is provided to Shoalhaven City Council for supply to local communities. Water is also released from the dam as environmental flows for the Shoalhaven River.[4][5]

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.[6] An innovative fish lift was constructed in 2009 to allow the fish to be collected and transferred over the dam wall.

See also

• List of reservoirs and dams in Australia

References

Further reading

• Gehrke, P. C.; Gilligan, D. M.; Barwick, M. (2002). "Changes in fish communities of the Shoalhaven River 20 years after construction of Tallowa Dam, Australia". River Research and Applications. 18 (3): 265–286. doi:10.1002/rra.669.

---