TheUpper Nepean Scheme is a series ofdams andweirs in the catchments of theCataract,Cordeaux,Avon andNepean rivers ofNew South Wales,Australia. The scheme includes four dams and two weirs, and a gravity-fed canal system that feeds into a large storagereservoir to provide water to theMacarthur andIllawarra regions, theWollondilly Shire, and metropolitanSydney. The four dams and associated infrastructure are individually listed on theNew South Wales State Heritage Register.[1][2][3][4]
By 1867, Sydney was outgrowing the water supply available fromBotany Swamps and theGovernor (Sir John Young) appointed a Commission to recommend a future water supply.[5]In 1869, the Commission recommended the Upper Nepean Scheme.[6] This comprised weirs on the Cataract and Nepean rivers, astorage reservoir at Prospect and 101.79 kilometres (63.25 mi) of pipelines, tunnels, canals and aqueducts to bring water from the 900 square kilometres (347 sq mi) catchment area to Sydney. Work on the Scheme began in 1880[7] and was completed in 1888.[8]: 15–17 The Scheme was a significant feat of engineering at the time of construction.
In June 1885 Sydney was in the grip of a severe drought and the Upper Nepean Scheme was incomplete. The Government accepted an offer fromHudson Brothers to bridge the gaps and deliver 14 megalitres; 3.6 million US gallons (3×10^6 imp gal) of water per day into Botany Swamps. Duplicating the entire length of the half built permanent scheme this became known as Hudsons' Temporary Scheme and was turned into the swamps on 30 January 1886.[9]: 64 [10] This emergency work was dismantled as the main scheme was completed.[8]: 18–19
As originally built, the Upper Nepean Scheme was capable of supporting an estimated population of 540,000. By 1902, Sydney had a population of 523,000 and was again in the grip of a severe drought. A Royal Commission appointed to report on Sydney's water supply recommended a dam on the Cataract River and construction commenced in the same year. Dams were subsequently built on each of the Cordeaux, Avon and Nepean rivers, with the last being completed in 1935. Each dam includes a public picnic area.[8]: 25–31 In total, the four dams hold 483,600 ML (1.064×1011 imp gal; 1.278×1011 US gal) and can safely provide 353 ML (78×10^6 imp gal; 93×10^6 US gal) per day.[8]: 268
The Scheme is now managed by theSydney Catchment Authority.
Further supplementary water supply is provided by a feed from theShoalhaven Scheme through various pumps, pipes, cuts and diversions.
TheCataract Dam is aheritage-listedgravity dam with an unlined side spillway extending from the left abutment. It is 56 metres (183 ft) tall, 247 metres (811 ft) long and holds 97,190 ML (2.138×1010 imp gal; 2.567×1010 US gal) of water.[8]: 268 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.[1] The core of the dam consists of large 2-to-4.5-long-ton (2.03 to 4.57 t; 2.24-to-5.04-short-ton) sandstone blocks, quarried onsite andcemented together. The downstream face is of mass pouredbasalt concrete, with abasalt facing. A readily accessible source of suitable rock was located some distance away at Sherbrooke, also known as Ferndale, situated near the top ofBulli Pass. To transport the basalt from the quarry to the dam construction site, a2 ft (610 mm) gauge steam tramway, 8.8 km (5.5 mi) long, was constructed.[11] Dam construction began in 1902 and was completed in 1907, and the spillway was widened in 1915.[8]: 27–28 Ernest Macartney de Burgh was the supervising engineer for the project from 1904.[12] PoetBanjo Paterson wrote a satirical ballad "The Dam that Keele Built" about the politics behind the construction of Cataract Dam.[13]
TheCordeaux Dam is a heritage-listedarch dam across theCordeaux River with an unlined side spillway on the left abutment. It is 58 metres (191 ft) high, 404 metres (1,327 ft) long and creates a reservoir which holds 93,640 ML (2.060×1010 imp gal; 2.474×1010 US gal). Construction began in 1918 and was completed in 1926[8]: 268 [14] at a cost ofA£945,000.[2] The wall consists of large sandstone blocks, quarried onsite and cemented together, faced with a combination of bluestone and sandstone concrete.[8]: 28–29 The dam featured a number of improvements in design and construction on the earlier-completed Cataract Dam. These included contraction joints between units of construction placed at intervals of 27 metres (90 ft); inspection galleries at upper and lower levels, together with piping for registering any ground water pressure.[2] The blue metal used in the construction of the dam was supplied from the Government Quarries atKiama and brought by rail toDouglas Park. From here it was conveyed by aerial ropeway across theNepean Gorge to an interchange on the eastern side where the material was transferred to a2 ft (610 mm) gauge steam tramway to a point adjacent to the dam site.[15]
TheAvon Dam is a heritage-listed arch dam across theAvon River; it is 72 metres (237 ft) tall, 223 metres (732 ft) long and its reservoir holds 146,700 ML (3.23×1010 imp gal; 3.88×1010 US gal). It has the largest capacity of all the dams in the Scheme. Construction of theheritage-listed dam wall began in 1921 and was completed in 1927[8]: 268 [16] at a cost ofA£1,047,000.[3] The dam construction and materials are the same as Cordeaux.[8]: 29 All materials for construction were transported fromBargo railway station on a specially built road, all the other dams in the scheme used rail transport.[14] There were some light tramways constructed at the dam site, however it would appear that no locomotives were employed; skips and other items being moved by winch, horse or manpower.[17]
TheNepean Dam is a heritage-listed arch dam across theNepean River; it is 82 metres (269 ft) tall and 216 metres (709 ft) long. Construction on the Dam began in 1926, construction was delayed for two years during the Depression, it was finally completed in 1935.[8]: 268 [18] The capacity is listed variously as 67,730 to 81,400 ML (1.490×1010 to 1.791×1010 imp gal; 1.789×1010 to 2.150×1010 US gal).[18][8]: 268 The Nepean Reservoir has a small storage capacity in relation to its large catchment area of 319 square kilometres (123 sq mi). While its capacity is much the same as that of Cataract and Cordeaux Reservoirs, its catchment basin is two and a half times as extensive as Cataract and three and a half times as extensive as Cordeaux. The Nepean Reservoir therefore fills more rapidly and, under normal conditions, is drawn upon more freely than the other reservoirs. The dam is located at an elevation of 325 metres (1,066 ft)above sea level and the construction cost wasA£2,062,000.[4]
Railway sidings were established on theMain Southern railway line at a point between Bargo andYerrinbool. Transport to the dam site was again by light railway, on this occasion of standard gauge. This avoided transhipment from the Government vehicles bringing materials from large commercial quarries, effectively making the line an extended privately owned siding. The line was 4 km (2.5 mi) long through gentle countryside. Trains were worked by a variety of locomotives, including a formerSydney Steam Tram Motor. Additionally, there was a system of narrow (610 mm /2 ft) gauge lines in use at the dam construction site.[19]
Additional work was carried out on the spillway between 1943 and 1947 to prevent scouring of the dam foundations.[8]: 31
Text is licensed by State of New South Wales (Department of Planning and Environment) underCC BY 4.0licence. Text is licensed by State of New South Wales (Department of Planning and Environment) underCC BY 4.0licence. Text is licensed by State of New South Wales (Department of Planning and Environment) underCC BY 4.0licence. Text is licensed by State of New South Wales (Department of Planning and Environment) underCC BY 4.0licence.
This Wikipedia article was originally based on the"New South Wales State Heritage Register" published by theGovernment of New South Wales underCC-BY 3.0 AU licence (accessed on 13 April 2012); and based on the"New South Wales State Heritage Register" published by theGovernment of New South Wales underCC-BY 3.0 AU licence (accessed on 29 September 2017); and based on the"New South Wales State Heritage Register" published by theGovernment of New South Wales underCC-BY 3.0 AU licence (accessed on 29 September 2017); and based on the"New South Wales State Heritage Register" published by theGovernment of New South Wales underCC-BY 3.0 AU licence (accessed on 29 September 2017).
34°13′40″S150°44′39″E / 34.227699°S 150.744232°E /-34.227699; 150.744232 (Broughtons Pass)
