Upper Nepean Scheme

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The Upper Nepean Scheme is a series of dams in the catchments of the Cataract, Cordeaux, Avon and Nepean rivers of New South Wales, Australia. The scheme includes four dams and supplies the Macarthur and Illawarra regions, the Wollondilly Shire, and metropolitan Sydney.

1 History
2 Cataract Dam
3 Cordeaux Dam
4 Avon Dam
5 Nepean Dam
6 References

[edit] History

The Upper Nepean Scheme was completed in 1888. The Scheme was a significant feat of engineering a the time of construction, it worked by diverting water from weirs on the Cataract, Cordeaux, Avon and Nepean rivers to Prospect Reservoir via 64 kilometers of tunnels, canals and aqueducts collectively known as the Upper Canal. Between 1907 and 1935 a dam was built on each of the rivers to increase the water supply for Sydney. The Scheme is managed by the Sydney Catchment Authority. Each dam includes a public picnic area.

In total, the four dams hold 510,660 megalitres and can safely provide 353 megalitres/day.

[edit] Cataract Dam

Cataract Dam Wall

Cataract Dam is a straight dam with an unlined side spillway extending from the left abutment. It is 56 meters tall; 247 m long; and it holds 94,300 megalitres of water. Cataract Dam was the first dam built in the Upper Nepean Scheme, it was also first dam in Australia to use pre-cast moulded concrete blocks for the upstream face of the dam. Construction began in 1902 and was completed in 1907, and the spillway was widened in 1915. Ernest Macartney de Burgh was the supervising engineer for the project from 1904^[1]. Poet Banjo Patterson wrote a satirical ballad "The Dam that Keele Built" about the politics behind the construction of Cataract Dam.

[edit] Cordeaux Dam

Cordeaux Dam #3 Wall

Cordeaux Dam is a curved dam with an unlined side spillway on the left abutment. It is 57 m height; 405 m long; and holds 93,640 megalitres. Construction began in 1918 and was completed in 1926.

[edit] Avon Dam

Avon Dam is a curved dam, it is 72 m tall; 223 m long; and it holds 214,360 megalitres. It has the largest capacity of all the dams in the Scheme. Construction began in 1921 and was completed in 1927. All materials for construction were transported on a specially built road, all the other dams in the scheme used rail trasport.

[edit] Nepean Dam

Nepean Dam Wall

Nepean Dam is a curved dam, it is 82 m tall; 216 m long; and holds 81,360 megalitres. Construction on the Dam began in 1926, construction was delayed for two years during the Depression, it was finally completed in 1935. Additional work was carried out on the spillway between 1943 and 1947 to prevent scouring of the dam foundations.