Cataract Dam
| Cataract Dam | |
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Cataract Dam wall
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| Country | Australia |
| Location | Macarthur, New South Wales |
| Coordinates | 34°15′56″S 150°48′11″E / 34.26556°S 150.80306°ECoordinates: 34°15′56″S 150°48′11″E / 34.26556°S 150.80306°E |
| Purpose | Potable water supply |
| Status | Operational |
| Construction began | 1902 |
| Opening date | 1907 |
| Construction cost | £329,136 |
| Owner(s) | Sydney Catchment Authority |
| Dam and spillways | |
| Type of dam | Gravity dam |
| Impounds | Cataract River |
| Height | 56 m (184 ft) |
| Length | 247 m (810 ft) |
| Dam volume | 112×103 m3 (4.0×106 cu ft) |
| Spillway type | Uncontrolled |
| Spillway capacity | 1,550 m3/s (55,000 cu ft/s) |
| Reservoir | |
| Total capacity | 94,300 ML (2.07×1010 imp gal; 2.49×1010 US gal) |
| Catchment area | 130 km2 (50 sq mi) |
| Surface area | 8,500 ha (21,000 acres) |
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Website Cataract Dam at Sydney Catchment Authority |
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Cataract Dam, one of four dams and weirs in the catchment of the Upper Nepean Scheme, in New South Wales, Australia, provides water to the Macarthur and Illawarra regions, the Wollondilly Shire, and metropolitan Sydney. Completed in 1907 under the supervision of Ernest Macartney de Burgh, the dam is currently managed by the Sydney Catchment Authority and is listed on the NSW State Heritage Register.
A straight dam with an unlined side spillway extending from the left abutment, it is 56 metres (184 ft) tall; 247 metres (810 ft) long; and it holds 94,300 megalitres (3,330×106 cu ft) 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. The downstream face is of mass poured basalt concrete, with a basalt facing. A readily accessible source of suitable rock was located at Sherbrooke, situated near the top of Bulli Pass. To transport the basalt from the quarry to the dam construction site, a 2 ft (610 mm) gauge steam tramway, 8.8 kilometres (5.5 mi) long, was constructed.
The dam is built of cyclopean masonry, composed of sandstone blocks weighing from 2 to 4.5 long tons (2.03 to 4.57 t; 2.24 to 5.04 short tons). These were quarried at the site and bedded in cement mortar. The vertical joints were filled with basalt or sandstone concrete. The upstream face consisted of basalt concrete moulded blocks set in a cement mortar. The downstream face was of basalt concrete, 1.8 metres (5 ft 11 in) thick in the lower section and 0.9 metres (2 ft 11 in) thick in the upper section. There were two lines of 122-centimetre (48 in) diameter pipes which passed through the dam and discharged water into the Nepean River. The flow is controlled by a Larner Johnson needle valve. The dam wall was given a decorative finish. The upstream parapet was castellated with sandstone blocks while the top of the downstream wall was corbelled in concrete. In approximately the midsection of the dam stands the valve house. This is finished in quarried sandstone blocks with ashlar coursing. It features a steeply pitched slate-covered pipped roof topped with finials and gables at either side.
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Wikipedia