Shoalhaven Scheme

The Shoalhaven Scheme is a dual-purpose water supply and hydro-electric power generation scheme in New South Wales. It was built as a joint project between the Electricity Commission of NSW and the NSW Metropolitan Water Sewerage and Drainage Board. Management has subsequently been passed from those bodies to Eraring Energy and the Sydney Catchment Authority.

Water supply

Water in the scheme is stored in three principle dams and reservoirs: Tallowa Dam, Fitzroy Falls Reservoir and Wingecarribee Reservoir.

Tallowa Dam is a concrete dam, located just downstream of the junction of the Kangaroo and Shoalhaven rivers. The dam was completed in 1976. It is 43 meters tall, 528 m long, and holds 85,500 megalitres. The lake created by the dam is called Lake Yarrunga.

Fitzroy Falls Reservoir consists of four separate earth and rockfill embankments, and was completed in 1974. The main embankment is 14 m tall and 1530 m long. The reservoir holds 23,500 megalitres. The 3300 m Wildes Meadow Canal connects the reservoir to the Burrawang Pumping Station. Burrawang Tunnel (2830 m) and Canal (1000 m) join the pumping station to the Wingecarribee Reservoir.

Wingecarribee Reservoir is located on the Wingecarribee River. The dam is an earth and rockfill structure that was completed in 1974. The dam is 19 m high, 1140 m long, and holds 25,900 megalitres.

Wingecarribee River is a tributary of Warragamba River, so water pumped into Wingecarribee Reservoir can be released into Warragamba Dam and hence the Sydney water supply. Water can also be released into Nepean Dam via a system of rock cuttings and tunnels known as Glenquarry Cut. Water from the Nepean Dam can be transferred to Sydney, or to Wollongong via Avon Dam.

Power generation

The Shoalhaven is a pumped storage scheme comprised of the Kangaroo Valley and Bendeela power stations. Water is pumped uphill from Lake Yarrunga into Fitzroy Falls Reservoir via Bendeela Pondage. The water can be released back into Lake Yarrunga to generate power. The scheme can generate up to 240 MW.

Environmental Consequences

The Shoalhaven River and its main tributary the Kangaroo River were once renowned as an Australian bass fishery. Unfortunately, Tallowa Dam has been a potent barrier to migratory native fish with estuarine/marine juvenile stages, blocking species including Australian bass from more than 80% of their former range in the Shoalhaven system. Recent stockings of hatchery bred Bass in Lake Yarrunga are a less than ideal attempt to remediate the situation. A fishway for Tallowa Dam has been discussed for more than 20 years but is yet to eventuate. Tallowa Dam has also suffered the illegal introduction of highly damaging exotic carp, which are now present in high densities.

References

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: 265–286.

See also

* Bendeela hydroelectric pumping station
* Kangaroo Valley hydroelectric pumping station

References

*Sydney Catchment Authority. [http://www.sca.nsw.gov.au/dams/shoalhaven.html Shoalhaven System]
* [http://www.eraring-energy.com.au/art-template-normal.asp?CID=55&AID=207 Eraring Energy] page on the Shoalhaven pumping stations