Nepean Dam

Item details


Name of item:	Nepean Dam
Type of item:	Built
Group/Collection:	Utilities - Water
Category:	Water Supply Reservoir/ Dam
Location:	Lat: -34.3353731497 Long: 150.6169604400
Primary address:	Avon Dam Road, Bargo, NSW 2574
Local govt. area:	Wingecarribee

Property description

Lot/Volume Code	Lot/Volume Number	Plan/Folio Code	Plan/Folio Number
LOT	1	DP	1055279
LOT	2	DP	1055279
LOT	3	DP	1055279
LOT	4	DP	1055279
PART LOT	12	DP	1092321
PART LOT	13	DP	1092321

Boundary:

As per the Heritage Curtilage image.

All addresses

Street Address	Suburb/town	LGA	Parish	County	Type
Avon Dam Road	Bargo	Wingecarribee			Primary Address
Avon Dam Road	Bargo	Wollondilly			Alternate Address

Owner/s

Organisation Name	Owner Category	Date Ownership Updated
Water NSW	State Government

Statement of significance:


	Nepean Dam was the fourth of the four water supply dams built as part of the development of the Upper Nepean Water Supply Scheme, one of the most important engineering works and items of public infrastructure in Australia, and had the highest wall of all the NSW water supply dams at the time of its construction. It was designed by the NSW Public Works Department under the direction of one of Australia’s leading water supply engineers, E.M. de Burgh. The completion of the Nepean Dam was a significant step in the continuing process of providing a reliable water supply for Sydney and surrounding areas as part of the Upper Nepean Scheme. Even by the international standards of the time, Nepean was a large dam and was a significant work of engineering in its day. It continues to play an important role as a major source of water supply for the Sydney region. Additionally, the Nepean Dam is a handsome, well proportioned structure with strong Stripped Classical style architectural character which complements the monumental nature of the structure and its attractive natural surroundings. Nepean Dam includes a range of ancillary structures which form components of the overall site, including residential cottages of various ages for operational staff and are representative of their age and type. The former Resident Engineer's cottage is an attractive example of a vernacular cottage of the early twentieth century. The public picnic grounds include a former construction railway platform now housing picnic shelters, and the site of the original construction village remains undeveloped and is now an overgrown archaeological site. The Nepean Dam picnic areas and gardens contain a cultural landscape resource - including remnants of its interwar period plantings, layout and detailing, and extensive areas of bushland - of regional value. The finely detailed dam structures of large-scaled concrete in Art Deco-style sit within a broader landscape setting of outstanding scenic quality.
	Date significance updated: 21 Jan 09
	Note: The State Heritage Inventory provides information about heritage items listed by local and State government agencies. The State Heritage Inventory is continually being updated by local and State agencies as new information becomes available. Read the Department of Premier and Cabinet copyright and disclaimer.

Description


Designer/Maker:	E. M. de Burgh
Builder/Maker:	Public Works Department / Metropolitan Water Sewerage and Drainage Board
Construction years:	1925-1935
Physical description:	The Nepean Dam is a large cyclopean masonry dam. This consists of large blocks of sandstone quarried at the site, embedded in and surrounded by sandstone concrete. To ensure water-tightness, all construction joints are grouted. The upstream face consists of blue metal concrete 5 feet (1.3m) thick while the downstream face is of similar material 3 feet (0.9m) thick. Both of the facing concrete sections are merged progressively into the central sandstone masonry concrete. All the latest improvements in dam design and construction of the day were embodied in the work, building upon the experience gained from the construction of the previous three Upper Nepean Scheme dams. Inspection galleries are provided, with pressure and drainage pipes from the foundations, and rubble drains lead into them. Provision is made for any leakage of water past the copper seals in the contraction joints to be conducted into the galleries and thence drained away. To facilitate the work of maintenance staff, an electric lift was provided in the wall. The water is discharged through two 36 inch (92cm) diameter outlet pipes controlled by Ring Falkner gate valves and FCD valves. After construction was complete and the dam had filled, the spillway weir was altered by the construction on the western side of the stream of a concrete channel approximately 2,000 feet (609.7m) long and 120 feet (36.6m) wide, widening to 432 feet (131.7m) at the discharge weir. The Nepean Reservoir has a small storage capacity in relation to its large catchment area. 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. Specifications of Nepean Dam: Area of lake: 881 acres (356.5 hectares). Area of catchment: 123 sq miles (319km2). Total capacity: 17,898 million gallons (81,400 million litres). Years of construction: 1926-1935. Cost: (Pounds)2,062,000 ($4,124,000). Crest level above sea level: 1,066 feet (325m). Amount of concrete in the wall: 300,218 cu yards (229,600 cu metres). Length of crest including pylons: 710 feet (216.4m). Length of spillway weir: 436 feet (132.9m). Width at crest: 20 feet (6.1m). Width at base: 225 feet (68.6m). Full supply level above sea level: 1,051 feet (320.3m). Greatest depth of water: 225 feet (68.6m). Average annual rainfall: 42.3 inches (1074mm). Average annual yield: 23,515 million gallons (106,993 million litres). Average annual evaporation: 38.5 inches (978mm). The Nepean Dam continues to supply Sydney with water. It is discharged as required into the river bed below the dam and flows to Pheasant's Nest where it is diverted by a weir to the Nepean Tunnel, 4 miles (7.2km) long, discharging into the Cataract Tunnel, 2 miles (3.2km) long, emerging into the Upper Canal, by which it is conveyed to Prospect Reservoir. The Nepean Dam is now also cross-connected to the Avon Dam, which supplies the Wollongong area, to provide additional water supply to that district. If necessary, it can also receive additional water from the Shoalhaven Scheme. Water is supplied to the Picton and Bargo districts from Nepean Dam, with this water treated and filtered in the Nepean Water Filtration Plant, a treatment facility added to the dam to improve the water quality to this district, which is now supplied directly from Nepean Dam. The Nepean Dam includes within its area three brick residential staff cottages, two apparently dating from the 1960s and one from the1980s, and two older weatherboard cottages, one of which, utilised by the Filtration Plant staff, is the original Resident Engineer's Cottage. Just north of the entrance to the Dam picnic area are the former Catchment workshops, a series of small corrugated iron and weatherboard utilitarian buildings which were formerly the central maintenance facility for the Upper Nepean Catchment area. They remain in use at a low scale by the Sydney Catchment Authority and include a weatherboard residential cottage similar to the second of the weatherboard residences at the Dam. The area of the former construction village for the Dam remains undeveloped and heavily overgrown, with remnant road borders and evidence of buildings visible on the ground. The public area has been maintained by the Water Board and its successors, with picnic grounds, landscaped gardens and a children's playground. Remnants of the interwar period landscape at the Nepean Dam site are mainly concentrated in two areas - around a small park, with cement faux rockwork bedding edges, to the east of the dam wall, including a long line of Roman Cypress (Cupressus sempervirens) along the spillway alignment; and in a park-like picnic area along a terrace above the dam. Features of the latter area include pleasant plantings of mixed deciduous and evergreen exotic trees and Australian trees enclosing a long raised shelf, which is the remnant railway platform from the temporary construction railway, with a series of small timber picnic shelters with a somewhat log cabin-style character. Nearby a considerable line of dry-packed sandstone walling has been used and drystone walling is used generally to control access. The main entry road includes the remains of an old Cypress avenue and an ornamental gum avenue.
Physical condition and/or Archaeological potential:	Good
	Date condition updated:27 Aug 09
Modifications and dates:	Scouring at the toe of the foundations of the dam made it necessary to alter the direction of the flow of floodwaters discharged over the spillway weir. This was done by constructing a concrete channel approximately 2,000 feet (609.7m) long, 120 feet (36.6m) wide, widening to 432 feet (131.7m) at the discharge weir. Construction of the channel commenced in July 1943, and was completed in November 1947. In the early 1970s, work was undertaken on Nepean Dam to alleviate uplift pressure on, and leakage through, the foundations of the dam wall, in accordance with modern design criteria. The downstream face of the wall was supported with an embankment of quarried sandstone blocks and sandstone fill, the latter being compacted by grid and vibratory rollers. It was similar to the work undertaken at the same time for Avon Dam. The original Glenfield-Kennedy needle valves have been replaced with Ring Faulkner gate valves and FCD valves. In 2006 a deepwater pumping station was built at Nepean Dam as part of the Metroplitan Water Plan. The station allows water to be transferred to Avon Dam even when the level of Nepean Dam is lower than Avon Dam. The building containing the pumping station was built in the same style to Nepean Dam. In 2008 the overhead crane was modified to make electric the east-west long travel of the overhead crane which was hand operated and had suffered critical failure in 2005.


Current use:	Water supply water storage
Former use:	Aboriginal land, water supply water storage

History

Historical notes:

Aboriginal land
This area was the traditional land of the Gandangara people (Garran ,1978, 530). The area is home to the Tharawal and Gundungurra people (Robinson, 2008).

Gundungurra or Gandangarra people lived in the Southern Highlands area, which includes Mittagong, for many thousands of years. People who spoke the Gundungurra language lived in the Blue Mountains, the Southern Highlands and the Goulburn Plains of New South Wales. They lived in small groups of extended family members, who were attached to particular areas of country (Di Johnson: 2004 in SHR database 5045486).

Gundungurra groups left archaeological evidence of their occupation throughout their traditional lands, including scarred trees where bark was removed for use as a boat or other object, grinding grooves on rocks where axes were ground, and occupation sites which include middens. Well-worn Gundungurra pathways on ridge tops were often the routes used as the first roads by colonists (Di Johnson 2004). Possibly this could have been the origin of the Old South Road... (SHR database 5045486).

One of the first places in the Gundungurra traditional homelands that most appealed to the Anglo-Celt settlers were the river flats of the Burragorang Valley (now flooded under Warragamba Dam). Even before the valley was officially surveyed in 1827-8, many early settlers were already squatting on blocks that they planned to officially occupy following the issue of freehold title grants. From the Burragorang Valley and using Aboriginal pathways, other valleys to the west were occupied and developed by the settlers with construction of outstations and stock routes. These cattle entrepreneurs were then followed by cedar-wood extractors and miners (Johnson, 2009, 4).

After Anglo-European settlers caused displacement of Gundungurra people, they often worked on farms or grazing properties within and adjacent to their traditional land (Di Johnson: 2004 in SHR database 5045486).

The Gundungurra traditional owners resisted the taking of their lands, and, relying on various laws of the colony at the time, continually applied for official ownership. Although their individual claims failed, in some kind of recognition of the significance of the designated tracts of land claimed, six Aboriginal Reserves (under the control of the NSW Aborigines Protection Board) were formally declared in the Burragorang Valley. Even after these reserves were revoked, many of the traditional owners remained, quietly refusing to leave their traditional homelands (ibid, 2009, 4).

Finally pushed into the 'Gully', a fringe development in West Katoomba from about 1894, the Gully community stayed together for more than 60 years until dispossessed of the Gully by the then Blue Mountains Shire Council so a group of local businessmen could develop a speedway that became known as the Catalina Race Track. The Gully people kept talking about areas of land they had walked in as children - the nearby Megalong and Kanimbla Valleys and the Burragorang Valley. They knew of the profound significance of these valleys for their parents and grandparents (ibid, 2009, 4).

Camden and the Cow Pastures:
The area is associated with the early history of the colony of New South Wales. Governor Hunter named it 'The Cowpastures' after cattle which had strayed from the Farm Cove settlement were discovered there in 1795 (to the south-west of Sydney). Due to the early European settlers, namely the Macarthurs, who established flourishing wool, wine and wheat industries here, the area is said to be the 'birthplace of the nation's wealth' (ibid, 2008).

Sydney's Water Supply:
The Upper Nepean Scheme was commenced in 1880 after supply from the Botany Swamps became insufficient to meet Sydney's growing water supply needs. The Upper Nepean Scheme was based on the diversion of the waters of four rivers, the Cataract, Cordeaux, Avon and Nepean, into a series of tunnels, canals and pipelines, collectively known as the Upper Canal, to be conveyed for storage in Prospect Reservoir, from which supply to Sydney was drawn.

By 1902, however, the water supply was found to be inadequate and a Royal Commission was held which recommended impounding the waters of the Cataract River by means of a major storage dam. The Cataract Dam was completed in 1907. In November 1918, a Board of Experts was appointed by the Government to draw up recommendations for the amplification of the Sydney water supply. It was upon the recommendations of this body, as approved by the Public Works Committee of the NSW Parliament, that not only Cordeaux, but also Avon and Nepean Dams were built. The Cordeaux Dam was completed in 1926 and the Avon Dam in 1927, on the Cordeaux and Avon Rivers respectively. As Cordeaux and Avon Dams were approaching completion, a fourth dam, Nepean Dam, was commenced in 1925.

The site chosen was on the Nepean River, about 7 miles (12.5km) above the point where the Cordeaux River joins the main stream at Pheasants Nest Pass and about 4 miles (6.4km) by road southeast of Bargo railway station. The dam was designed by engineers of the Public Works Department under the direction of the Chief Engineer for Water Supply and Sewerage, EM de Burgh.

Construction of the dam was undertaken by the Public Works Department until 1 September 1928, at which time the Department was re-organised and the majority of the staff associated with water supply were transferred to the Board of Water Supply and Sewerage, who continued the work on the dam. At that date, excavation for the foundations of the wall was complete and placing of concrete about to begin. Most of the plant and equipment used for the construction of Avon Dam was dismantled and re-erected at the Nepean Dam site, including the cableways and timber towers. A suspension bridge was constructed across the Nepean River which was later used at Warragamba Dam.

A township for workers was constructed of timber obtained from the clearing of the catchment for the Avon Dam. This township provided four and five-roomed cottages for the married men and had metalled roads with concrete kerbing. A typical working man's accommodation consisted of a simple timber hut with a galvanised roof. Later, a barracks was constructed for single men. A Public School and recreation halls were also provided, as were full-time medical staff and facilities.

Shortly after construction of the dam was transferred from the Public Works Department to the Water Board, it was decided upon the recommendation of the Chief Engineer the Board, G Haskins, that the height of the dam wall be increased by 25ft (7.6m). This added nearly 50% to the storage capacity of the dam.
Work on the dam continued until March 1930, when the depression compelled the Board first to curtail and then suspend work completely. The work recommenced on 12 June 1933 and continued without interruption until completion of the dam in 1935. Although the dam was ready to store water by September, 1935, there was little rainfall on its catchment during the ensuing three years; however, by October 1938 the dam was overflowing. At this time it was realised that scouring at the toe of the foundations of the dam required an alteration to the direction of the flow of floodwaters discharged over the spillway weir. This was done by constructing a concrete channel approximately 2,000 feet (609.7m) long, 120 feet (36.6m) wide, widening to 432 feet (131.7m) at the discharge weir. Construction of the channel commenced in July 1943, and was completed in November 1947.

In in the late 1960's, as part of a plan to interconnect the various water supply systems for Sydney Wollongong and Sutherland, a tunnel was constructed between the Nepean Dam and the Avon Dam (which now supplies the Wollongong area). This allows water to be transferred in either direction, as required.

In the 1980s, work was undertaken on Nepean Dam to alleviate uplift pressure on, and leakage through, the foundations of the dam wall, in accordance with modern design criteria. The downstream face of the wall was supported with an embankment of quarried sandstone blocks and sandstone fill, the latter being compacted by grid and vibratory rollers. It was similar to the work undertaken at the same time for Avon Dam.

In December 2016 the state government approved the controversial South 32 Dendrobium coal mine, in the Metropolitan Special Area, created to protect waters of Avon, Cataract, Cordeaux and Nepean reservoirs (Hannam, 2016, 14).

Historic themes

Australian theme (abbrev)	New South Wales theme	Local theme
1. Environment-Tracing the evolution of a continent's special environments	Environment - naturally evolved-Activities associated with the physical surroundings that support human life and influence or shape human cultures.	Natural - regenerating native flora valued for conservation purposes-
3. Economy-Developing local, regional and national economies	Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings	Developing local, regional and national economies-National Theme 3
3. Economy-Developing local, regional and national economies	Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings	Unseen but Present-
3. Economy-Developing local, regional and national economies	Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings	Landscapes and parklands of distinctive styles-
3. Economy-Developing local, regional and national economies	Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings	Landscapes of institutions - productive and ornamental-
3. Economy-Developing local, regional and national economies	Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings	Landscapes of industrial production-
3. Economy-Developing local, regional and national economies	Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings	Landscapes drowned beneath dam waters-
3. Economy-Developing local, regional and national economies	Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings	Landscapes of urban and rural interaction-
3. Economy-Developing local, regional and national economies	Technology-Activities and processes associated with the knowledge or use of mechanical arts and applied sciences	Technologies for reticulated water supply-
4. Settlement-Building settlements, towns and cities	Accommodation-Activities associated with the provision of accommodation, and particular types of accommodation – does not include architectural styles – use the theme of Creative Endeavour for such activities.	Building settlements, towns and cities-National Theme 4
4. Settlement-Building settlements, towns and cities	Land tenure-Activities and processes for identifying forms of ownership and occupancy of land and water, both Aboriginal and non-Aboriginal	Administering and alienating Crown lands-
4. Settlement-Building settlements, towns and cities	Towns, suburbs and villages-Activities associated with creating, planning and managing urban functions, landscapes and lifestyles in towns, suburbs and villages	Planning relationships between key structures and town plans-
4. Settlement-Building settlements, towns and cities	Towns, suburbs and villages-Activities associated with creating, planning and managing urban functions, landscapes and lifestyles in towns, suburbs and villages	Developing towns in response to topography-
4. Settlement-Building settlements, towns and cities	Towns, suburbs and villages-Activities associated with creating, planning and managing urban functions, landscapes and lifestyles in towns, suburbs and villages	Creating landmark structures and places in regional settings-
4. Settlement-Building settlements, towns and cities	Towns, suburbs and villages-Activities associated with creating, planning and managing urban functions, landscapes and lifestyles in towns, suburbs and villages	Shaping coastal settlement-
4. Settlement-Building settlements, towns and cities	Towns, suburbs and villages-Activities associated with creating, planning and managing urban functions, landscapes and lifestyles in towns, suburbs and villages	Suburban Consolidation-
4. Settlement-Building settlements, towns and cities	Towns, suburbs and villages-Activities associated with creating, planning and managing urban functions, landscapes and lifestyles in towns, suburbs and villages	20th Century infrastructure-
4. Settlement-Building settlements, towns and cities	Towns, suburbs and villages-Activities associated with creating, planning and managing urban functions, landscapes and lifestyles in towns, suburbs and villages	Outlying settlements-
4. Settlement-Building settlements, towns and cities	Utilities-Activities associated with the provision of services, especially on a communal basis	Water and drainage-
4. Settlement-Building settlements, towns and cities	Utilities-Activities associated with the provision of services, especially on a communal basis	Water supply-
4. Settlement-Building settlements, towns and cities	Utilities-Activities associated with the provision of services, especially on a communal basis	Providing drinking water-
5. Working-Working	Labour-Activities associated with work practises and organised and unorganised labour	Working complex machinery and technologies-
5. Working-Working	Labour-Activities associated with work practises and organised and unorganised labour	Working independently on the land-
5. Working-Working	Labour-Activities associated with work practises and organised and unorganised labour	Working on public infrastructure projects-
5. Working-Working	Labour-Activities associated with work practises and organised and unorganised labour	Working in the public service-
5. Working-Working	Labour-Activities associated with work practises and organised and unorganised labour	Working on the land-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	State government-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - surveying of land-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - administration of land-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - building and operating public infrastructure-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - providing community facilities-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Public works-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - providing reticulated water-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - public water supply-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - public land administration-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - town and country planning-
7. Governing-Governing	Government and Administration-Activities associated with the governance of local areas, regions, the State and the nation, and the administration of public programs - includes both principled and corrupt activities.	Developing roles for government - conserving cultural and natural heritage-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Monuments-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Developing cultural institutions and ways of life-National Theme 8
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Industrial buildings-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Landscaping - late 20th century-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Landscaping - neglected, regenerating to bushland-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Landscaping - 20th century interwar-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Landscaping - 20th century post WW2-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Building in response to natural landscape features.-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Designing in an exemplary architectural style-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Applying architectural design to utlilitarian structures-
8. Culture-Developing cultural institutions and ways of life	Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities.	Technological innovation and design solutions-
8. Culture-Developing cultural institutions and ways of life	Domestic life-Activities associated with creating, maintaining, living in and working around houses and institutions.	Living near factories and industrial complexes-
8. Culture-Developing cultural institutions and ways of life	Domestic life-Activities associated with creating, maintaining, living in and working around houses and institutions.	Ways of life 1900-1950-
8. Culture-Developing cultural institutions and ways of life	Domestic life-Activities associated with creating, maintaining, living in and working around houses and institutions.	Ways of life 1950-2000-
8. Culture-Developing cultural institutions and ways of life	Domestic life-Activities associated with creating, maintaining, living in and working around houses and institutions.	Living on the urban fringe-
8. Culture-Developing cultural institutions and ways of life	Leisure-Activities associated with recreation and relaxation	Outdoor relief-
8. Culture-Developing cultural institutions and ways of life	Leisure-Activities associated with recreation and relaxation	Tourism-
8. Culture-Developing cultural institutions and ways of life	Leisure-Activities associated with recreation and relaxation	Visiting heritage places-
8. Culture-Developing cultural institutions and ways of life	Leisure-Activities associated with recreation and relaxation	Activities associated with relaxation and recreation-
8. Culture-Developing cultural institutions and ways of life	Leisure-Activities associated with recreation and relaxation	Visiting lookouts and places of natural beauty-
8. Culture-Developing cultural institutions and ways of life	Social institutions-Activities and organisational arrangements for the provision of social activities	Joining together to study and appreciate philosophy-
8. Culture-Developing cultural institutions and ways of life	Social institutions-Activities and organisational arrangements for the provision of social activities	Places of informal community gatherings-
8. Culture-Developing cultural institutions and ways of life	Social institutions-Activities and organisational arrangements for the provision of social activities	Developing local clubs and meeting places-
8. Culture-Developing cultural institutions and ways of life	Social institutions-Activities and organisational arrangements for the provision of social activities	Belonging to an historical society or heritage organisation-
9. Phases of Life-Marking the phases of life	Persons-Activities of, and associations with, identifiable individuals, families and communal groups	Associations with E.M. deBurgh, Public Works Chief Engineer-
9. Phases of Life-Marking the phases of life	Persons-Activities of, and associations with, identifiable individuals, families and communal groups	Associations with the NSW Department of Public Works-

Assessment of significance


SHR Criteria a) [Historical significance]	Nepean Dam is located within the Upper Nepean Catchment Area which was developed with the completion of the Cataract and Nepean Tunnels in 1888, as the fourth source of water supply for Sydney. The potential of the Upper Nepean Catchment Area to supply water was fully developed through the construction of four major dams between 1903 and 1936. Nepean Dam is the last of these dams to have been completed. The Upper Nepean Catchment Area continues to supply the regions of Sydney and Illawarra, with the Nepean Dam providing a supply to Sydney, Macarthur, Bargo and Illawarra (through the Avon/Nepean Tunnel) regions. Nepean Dam was the fifth of the major water supply/irrigation dams constructed in NSW during the first half of the twentieth century. Whilst the dam was designed by the Public Works Department of NSW, the technologies used in the dam are representative5 of methods developed by that authority, the planning and scale of the construction techniques are more representative of the Water Board. In conjunction with other Metropolitan Dams and Woronora Dam built in 1941, the impounded water of Nepean Dam provided one of the major sources of water for domestic and industrial consumption in metropolitan Sydney, the largest city in NSW. In providing water for metropolitan Sydney during this era the dam, in ensuring security of supply, contributed to the extensive residential, commercial and industrial development of Sydney during the 1930s and 1950s. Nepean Dam was constructed over a period of ten years between 1926 and 1936, a protracted construction period which is directly related tot he Great Depression and a period of Government financial stringency. The completion of the dam during this period was one of the major public works projects undertaken in the State.
SHR Criteria b) [Associative significance]	The design and construction of Nepean Dam was initially undertaken by the Water Supply and Sewerage Branch of the NSW Public Works Department, and later developed by the Construction Branch of the Water Board. The construction of the dam drew upon the knowledge and experience of a number of engineers employed in the branches including E.M. de Burgh (Chief Engineer), and Gerald Haskins (the first engineer-in-chief of the former Water Board).
SHR Criteria c) [Aesthetic significance]	The wall of Nepean Dam is an engineering work imbued with a sense of high aesthetic value expressed through the short curved high wall set with the steeply sided valley of the Nepean River. The design and finishes of the crest house and lower valve house in the Inter War Stripped Classical style were prepared by the engineers of the Water Board. The architectural detailing evokes a sense of monumentalism that is ideally suited to the context of the dam. The dam is set within the valley of the Nepean River. Upstream of the dam wall this setting is characterised by the broad expanse of the pool of water bordered by the crests of the valley sides. Downstream of the dam wall the setting is characterised by the steeper inclines that graduate into the gorge created by the river’s flow over time. Collectively this topography at time of high water level imparts a picturesque scene when viewed from select vantage points above and on the dam wall. The former resident officer’s cottage erected at the time of the dam’s construction to house the resident engineer is an excellent and intact example of the high standard of accommodation provided for resident Public Works Department Senior staff.
SHR Criteria d) [Social significance]	The dam and grounds are recognised by the National Trust of Australia (NSW) as being a place which is part of the cultural environment of Australia, which has aesthetic, historical, architectural, archaeological, scientific and social significance for future generations, as well as for the present community of NSW. The dam and grounds are recognised by the Heritage Council of NSW as a place which is of significance to NSW in relation to its historical, scientific, cultural, social, archeological, natural and aesthetic values.
SHR Criteria e) [Research potential]	The cyclopean masonry of the dam is an excellent late example of this type of gravity dam construction in the Inter War era incorporating inspection galleries, contraction joints, and ground surface drainage system which demonstrate the principal characteristics of this technology at this time. Terraces and platforms adjoining the dam abutments demarcate the location of plant and equipment used in the construction of the dam, in particular the location of the cableway headtowers, the railway terraces and concrete mixing plant platform. The hillside near the upper picnic area was the site of the original construction township and retains an intact road formation, kerbing and guttering and tennis courts from that era. The integrity is such that collectively these features may potentially provide further insight into the lifestyles of the employees that constructed the dam.
SHR Criteria f) [Rarity]	The wall of the Nepean Dam is the highest of all the dams constructed in the Upper Nepean Catchment Area. Nepean Dam is one of three dams in NSW which incorporate extensive Inter War Stripped Classical architectural detailing. The crest and valve houses and inlet works retain original ironwork which represent a substantial repository of water supply delivery technology of the era. The use of an electronic lift in the wall (albeit now decommissioned) is a first for NSW. The completion of the dam necessitated the construction of a standard gauge (1835mm) railway line from Bargo which is unique in context of dam construction in NSW. The extent of foresight in planning the execution and design of the construction township is likely to be a first ion NSW in regard to dam construction, setting a practice which was further developed at Woronora Dam, and came to be exemplified at Warragamba Dam. The remnant platforms and terraces of the construction area are the largest in scale and most intact in regard to finishes and planning of all four of the Metropolitan Dams. The means of delivering stores and raw material through the network of railway lines and raised platforms, and the system of suspension footbridge and aerial stone ropeway to provide access and material over the gorge were particularly sophisticated for the time and foretells later developments at Warragamba Dam. The reservoir of the Nepean Dam is the second largest source of water in the whole of the network administered by SCA for the supply of metropolitan Sydney.
SHR Criteria g) [Representativeness]	Nepean Dam is representative of a type of dam (cyclopean masonry gravity dam) constructed in NSW by the Water Supply and Sewerage Branch of the Public Works Department during the first half of the twentieth century. Key representative e attributes of the dam’s design and construction include the use of cyclopean masonry bedded in sandstone concrete, use of blue metal concrete in the wall facings, use of a spillway set away from the gravity wall, valve and crest houses attractively designed and finished to a high standard, the use of an array of upstream intakes to regulate the quality of water supply, the internal inspection gallery, the foundation drainage system, the contraction joints, and the internal drainage system. The upgrading works to the spillway and dam wall in the 1980’s, with the rock embankment to make the dam meet modern safety requirements are representative of modern day safe operating practice. The construction technologies used at Nepean Dam are representative of dams constructed in NSW through the first half of the twentieth century. Key representative attributes include the use of cableways, the building of temporary camps to house labourers and tradesman, building of semi-permanent cottages to house salaried staff, the construction of terraced platforms for plant and machinery, mechanisation of concrete production, the construction of a purpose built road of access and tramway to transport men, supplies and materials from the nearest railhead to the construction site, the building of permanent infrastructure such as water supply for plant and men and horses, and the use of electricity to power plant and equipment. The rehabilitation of tracts of land scarred in the construction process employed at Nepean Dam through beautification works is representative of practices undertaken at other dams throughout NSW. Key representative attributes of this practice include utilising the former terraced construction platforms as picnic areas and lookouts, and utilising the former construction roads and tramway for vehicular access to the dam site and dam wall. The practice of ongoing maintence of the Nepean Dam wall after completion through the surveillance of resident staff and workshop facilities is representative of procedures undertaken at other dams and weirs constructed in NSW. The provision of public amenity at the dam site is representative of the use of large water supply and irrigation dams in NSW as places for recreation by the greater community.
Integrity/Intactness:	The Nepean Dam has a high level of integrity, though the downstream face of the dam is now covered by an embankment of sandstone. It retains two of its original staff residences and the site of the construction village appears to be relatively undisturbed by later usage. The site contains partially intact period landscape design features.
Assessment criteria:	Items are assessed against the State Heritage Register (SHR) Criteria to determine the level of significance. Refer to the Listings below for the level of statutory protection.

Recommended management:

Recommended Management: Manage the place and its components in accordance with the NSW Heritage Office Management Principles and Guidelines for NSW Agencies including the Minimum Standards of Maintenance and Repair. Recommended Management: Implement the Conservation Management Plan (Graham Brookes & Assoc., 2002). Recommended Management: Undertake environmental impact assessment (EIA) when planning works on the site (refer to SCA's EIA Policy). Prepare a Statement of Heritage Impact and gain S60 or S140 Heritage Office approval prior to undertaking any non-exempt works on the site. Recommended Management: Implement bushfire management plans for the Metropolitan Special Area. Recommended Management: Carry out annual condition inspections and report condition in SCA annual report. Recommended Management: Consult experienced heritage practitioners and the SCA's Planning and Assessment Team during the preparation and execution of works to the place. Recommended Management: Prepare a maintenance schedule for the item(s) in Maximo.

Recommendations

Management Category	Description	Date Updated
Recommended Management	Review a Conservation Management Plan (CMP)
Recommended Management	Prepare a maintenance schedule or guidelines
Recommended Management	Carry out interpretation, promotion and/or education

Procedures /Exemptions

Section of act	Description	Title	Comments	Action date
CMP-Endorse	Conservation Plan submitted for endorsement	Metropolitan Dams, NSW: Conservation Management Plan (Graham Brooks and Associates, Feb 2002)		Jun 27 2003
57(2)	Exemption to allow work	Standard Exemptions	HERITAGE ACT 1977 ORDER UNDER SECTION 57(2) TO GRANT STANDARD EXEMPTIONS FROM APPROVAL I, Penny Sharpe, the Minister for Heritage, on the recommendation of the Heritage Council of New South Wales and under section 57(2) of the Heritage Act 1977: revoke the order made on 2 June 2022 and published in the Government Gazette Number 262 of 17 June 2022; and grant an exemption from section 57(1) of the Act in respect of the engaging in or carrying out the class of activities described in clause 2 Schedule A in such circumstances specified by the relevant standards in clause 2 Schedule A and General Conditions in clause 3 Schedule A. This Order takes effect on the date it is published in the NSW Government Gazette. Dated this 29th day of October 2025 The Hon Penny Sharpe MLC Minister for Heritage For more information on standard exemptions click on the link below.	Nov 7 2025

Standard exemptions for engaging in or carrying out activities / works otherwise prohibited by section 57(1) of the Heritage Act 1977

Listings

Heritage Listing	Listing Title	Listing Number	Gazette Date
Heritage Act - State Heritage Register		01368	18 Nov 99
Heritage Act - s.170 NSW State agency heritage register		125181
Heritage study	Nepean Dam tramway site		01 Jan 92
National Trust of Australia register	Nepean Dam - wall etc	1420

Study details

Title	Year	Number	Author	Inspected by	Guidelines used
Sydney Water Heritage Study	1996	125181	Graham Brooks and Associates Pty Ltd	GRAHAM BROOKS AND ASSOCIATES PTY LTD. 1 July 1996	Yes
Macarthur Heritage Study	1986		JRC Planning Services		No
Macarthur Region Heritage Study	1992		Macarthur Development Board		No

References, internet links & images

Type	Author	Year	Title	Internet Links
Written	Aird W. V.	1961	The Water Supply, Sewerage and Drainage of Sydney.
Tourism	Attraction Homepage	2007	Nepean Dam - Wall & Valve House	View detail
Other	Australian Museum Business Services	2008	Statement of heritage impact: Cataract, Cordeaux & Nepean Dams: Environmental Flow Releases for the Upper Hawkesbury-Nepean River	View detail
Written	b cubed sustainability Pty Ltd	2005	Nepean Dam Storage Access Heritage Impact Statement
Written	Beasley M.	1988	The Sweat of their Brows - 100 yrs of the Sydney Water Board 1888 - 1988
Written	Hannam, Peter	2016	'Controversial South32 mine wins nod - Mining: concerns for groundwater
Written	Heritage Concepts Pty Ltd	2005	Archaeological Assessment
Written	M Simpson	1985	Nepean Dam Wall
Written	Nick Jackson, Matthew Taylor, Jon Breen	2002	Metropolitan Dams Conservation Management Plan Vol.5, Nepean Dam NSW	View detail
Tourism	Tourism NSW	2007	Nepean Dam	View detail

Note: internet links may be to web pages, documents or images.

(Click on thumbnail for full size image and image details)

Data source


The information for this entry comes from the following source:
Name:	Heritage NSW
Database number:	5051477
File number:	H08/00193; 125181; 13/03104

Every effort has been made to ensure that information contained in the State Heritage Inventory is correct. If you find any errors or omissions please send your comments to the Database Manager.

All information and pictures on this page are the copyright of Heritage NSW or respective copyright owners.