The Upper Nepean Scheme is a series of dams and

weir A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. Weirs are also used to control the flow of water for outlets of l ...

s in the catchments of the

Cataract A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colors, blurry or double vision, halos around light, trouble ...

, Cordeaux, Avon and Nepean rivers of

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

. The scheme includes four dams and two weirs, and a gravity-fed canal system that feeds into a large storage

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contr ...

to provide water to the Macarthur and

Illawarra The Illawarra is a coastal region in the Australian state of New South Wales, nestled between the mountains and the sea. It is situated immediately south of Sydney and north of the South Coast region. It encompasses the two cities of Wollong ...

regions, the Wollondilly Shire, and metropolitan

Sydney Sydney ( ) is the capital city of the state of New South Wales, and the most populous city in both Australia and Oceania. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about towards the Blue Mounta ...

. The four dams and associated infrastructure are individually listed on the

New South Wales State Heritage Register The New South Wales State Heritage Register, also known as NSW State Heritage Register, is a heritage list of places in the state of New South Wales, Australia, that are protected by New South Wales legislation, generally covered by the Heritag ...

History

By 1867, Sydney was outgrowing the water supply available from

Botany Swamps The Botany Water Reserves are a heritage-listed former water supply system and now parkland and golf course at 1024 Botany Road, Mascot, Bayside Council, Sydney, New South Wales, Australia. It was designed by City Engineers, W. B. Rider, E. Bel ...

and the

Governor A governor is an administrative leader and head of a polity or political region, ranking under the head of state and in some cases, such as governors-general, as the head of state's official representative. Depending on the type of political ...

( Sir John Young) appointed a Commission to recommend a future water supply. In 1869, the Commission recommended the Upper Nepean Scheme. This comprised weirs on the Cataract and Nepean rivers, a storage reservoir at Prospect and of pipelines, tunnels, canals and aqueducts to bring water from the catchment area to Sydney. Work on the Scheme began in 1880 and was completed in 1888. 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 from

Hudson Brothers The Hudson Brothers were an American musical group formed in Portland, Oregon, consisting of brothers Bill Hudson, Brett Hudson and Mark Hudson. They were discovered by a record producer while recording music at a local studio, and offered a rec ...

to bridge the gaps and deliver 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. This emergency work was dismantled as the main scheme was completed. 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. In total, the four dams hold and can safely provide per day. The Scheme is now managed by the

Sydney Catchment Authority The Sydney Catchment Authority was a statutory authority of the Government of New South Wales created in 1999 to manage and protect drinking water catchments and catchment infrastructure, and supplies bulk water to its customers, including Sydn ...

. Further supplementary water supply is provided by a feed from the Shoalhaven Scheme through various pumps, pipes, cuts and diversions.

Associated dams

Cataract Dam

The

Cataract Dam The Cataract Dam is a heritage-listed dam in Cataract (formerly Appin), New South Wales, Australia, provides water to the Macarthur and Illawarra regions, the Wollondilly Shire, and metropolitan Sydney. It is one of four dams and weirs in the ca ...

is a

heritage-listed This list is of heritage registers, inventories of cultural properties, natural and man-made, tangible and intangible, movable and immovable, that are deemed to be of sufficient heritage value to be separately identified and recorded. In many i ...

gravity dam A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using only the weight of the material and its resistance against the foundation to oppose the horizontal pressure of water pushing against it ...

with an unlined side spillway extending from the left abutment. It is tall, long and holds 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 core of the dam consists of large sandstone blocks, quarried onsite and

cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixe ...

ed together. The downstream face is of mass poured basalt concrete, with a

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

facing. A readily accessible source of suitable rock was located some distance away at Sherbrooke, also known as Ferndale, situated near the top of Bulli Pass. To transport the basalt from the quarry to the dam construction site, a gauge steam tramway, long, was constructed. 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. Poet

Banjo Paterson Andrew Barton "Banjo" Paterson, (17 February 18645 February 1941) was an Australian bush poet, journalist and author. He wrote many ballads and poems about Australian life, focusing particularly on the rural and outback areas, including the ...

wrote a satirical ballad "The Dam that Keele Built" about the politics behind the construction of Cataract Dam.

Cordeaux Dam

The Cordeaux Dam is a heritage-listed

arch dam An arch dam is a concrete dam that is curved upstream in plan. The arch dam is designed so that the force of the water against it, known as hydrostatic pressure, presses against the arch, causing the arch to straighten slightly and strengthe ...

across the

Cordeaux River The Cordeaux River, a perennial river of the Hawkesbury- Nepean catchment, is located in the Southern Highlands and Macarthur regions of New South Wales, Australia. Course The Cordeaux River rises on the western slopes of the Illawarra escar ...

with an unlined side spillway on the left abutment. It is high, long and creates a reservoir which holds . Construction began in 1918 and was completed in 1926 at a cost of A£945,000. The wall consists of large sandstone blocks, quarried onsite and cemented together, faced with a combination of bluestone and sandstone concrete. 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 ; inspection galleries at upper and lower levels, together with piping for registering any ground water pressure. The blue metal used in the construction of the dam was supplied from the Government Quarries at

Kiama Kiama () is a coastal town 120 kilometres south of Sydney in the Illawarra. One of the main tourist attractions is the Kiama Blowhole. Kiama features several popular surfing beaches and caravan parks, and numerous alfresco cafes and restaurants ...

and brought by rail to

Douglas Park Douglas Park was a football stadium in Hamilton, South Lanarkshire, the home ground of Hamilton Academical from 1888 to 1994. The stadium holds the record for Hamilton Academical's largest ever attendance, 28,690 people against Hearts in 1 ...

. From here it was conveyed by aerial ropeway across the

Nepean Gorge The Nepean Gorge is a gorge on the Nepean River west of Sydney, New South Wales, Australia. The gorge is located south of the western suburb of Penrith and is administered and protected by the National Parks and Wildlife Service. It is c ...

to an interchange on the eastern side where the material was transferred to a gauge steam tramway to a point adjacent to the dam site.

Avon Dam

The Avon Dam is a heritage-listed arch dam across the Avon River; it is tall, long and its reservoir holds . It has the largest capacity of all the dams in the Scheme. Construction of the

dam wall began in 1921 and was completed in 1927 at a cost of A£1,047,000. The dam construction and materials are the same as Cordeaux. All materials for construction were transported from

Bargo Bargo is a town in the Macarthur Region, New South Wales, Australia, in the Wollondilly Shire. It is approximately 100 km south west of Sydney. It is situated between the township of Tahmoor (north) and the village of Yanderra (south) ...

railway station on a specially built road, all the other dams in the scheme used rail transport. 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.

Nepean Dam

The Nepean Dam is a heritage-listed arch dam across the

Nepean River Nepean River (Darug: Yandhai), is a major perennial river, located in the south-west and west of Sydney, New South Wales, Australia. The Nepean River and its associated mouth, the Hawkesbury River, almost encircles the metropolitan region of ...

; it is tall and long. Construction on the Dam began in 1926, construction was delayed for two years during the Depression, it was finally completed in 1935. The capacity is listed variously as . The Nepean Reservoir has a small storage capacity in relation to its large catchment area of . 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

above sea level Height above mean sea level is a measure of the vertical distance ( height, elevation or altitude) of a location in reference to a historic mean sea level taken as a vertical datum. In geodesy, it is formalized as '' orthometric heights''. Th ...

and the construction cost was A£2,062,000. Railway sidings were established on the Main Southern railway line at a point between Bargo and

Yerrinbool Yerrinbool is a Northern Village of the Southern Highlands of New South Wales, Australia, in the Wingecarribee Shire, and is accessible from the Hume Highway (via Bargo or Alpine) and is about a drive from nearby Mittagong. It is to Hill ...

. 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 long through gentle countryside. Trains were worked by a variety of locomotives, including a former Sydney Steam Tram Motor. Additionally, there was a system of narrow () gauge lines in use at the dam construction site. Additional work was carried out on the spillway between 1943 and 1947 to prevent scouring of the dam foundations.

Gallery

Image:Cataract_at_capacity.jpg, Cataract reservoir at full capacity, discharging through spillway Image:Cataract_spillway.jpg, Detail of Cataract Dam spillway Image:Cataract_outlet_works.jpg, Outlet works at Cataract Dam Avon Dam plate.jpg, Avon Dam plate Nepean Dam plate.jpg, Nepean Dam plate

References

Attribution

This Wikipedia article was originally based on th
''"New South Wales State Heritage Register"''
published by the

Government of New South Wales The Government of New South Wales, also known as the NSW Government, is the States and territories of Australia, Australian state democratic administrative authority of New South Wales. It is currently held by a coalition of the Liberal Party o ...

unde
CC-BY 3.0 AU
licence (accessed on 13 April 2012); and based on th
''"New South Wales State Heritage Register"''
published by the

unde
CC-BY 3.0 AU
licence (accessed on 29 September 2017); and based on th
''"New South Wales State Heritage Register"''
published by the

unde
CC-BY 3.0 AU
licence (accessed on 29 September 2017).