Cordeaux Dam | NSW Environment & Heritage

Culture and heritage


Cordeaux Dam

Item details

Name of item: Cordeaux Dam
Type of item: Built
Group/Collection: Utilities - Water
Category: Water Supply Reservoir/ Dam
Location: Lat: -34.3353731497 Long: 150.7499066490
Primary address: Cordeaux River, Cordeaux, NSW
Local govt. area: Wollondilly
Local Aboriginal Land Council: Illawarra


As per the Heritage Curtilage image.
All addresses
Street AddressSuburb/townLGAParishCountyType
Cordeaux RiverCordeauxWollondilly  Primary Address


Organisation NameOwner CategoryDate Ownership Updated
Water NSWState Government 

Statement of significance:

Cordeaux Dam was the second 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 still has the longest wall of all the NSW water supply dams. 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 Cordeaux 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, Cordeaux 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 supply for the Sydney region.

Cordeaux Dam is a handsome, well proportioned structure with strong Egyptian style architectural character which complements the monumental nature of the structure and its attractive natural surroundings. Cordeaux Dam includes a range of ancillary structures which form components of the overall site, including residential cottages of various ages for operational staff, one of which appears to date from the construction of the dam. This latter is associated with the Residential Engineer for construction and operation of the dam and is a fine example of a late Federation Bungalow style building. The other residences are representative of their age and type.

The public picnic grounds and gardens attached to the Cordeaux Dam contain a cultural landscape resource - including remnants of its interwar period plantings, layout and detailing, and extensive areas of bushland. There is evidence in the landscape design, particularly in the use of palms and tree ferns and battered stonework retaining walls, of an intention to continue the Egyptian Revival references apparent in the design of the main dam structures.
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 OEH copyright and disclaimer.


Designer/Maker: E.M. De Burgh and Department of Public Works
Builder/Maker: Department of Public Works
Construction years: 1918-1926
Physical description: Cordeaux Dam is a cyclopean masonry dam composed of sandstone blocks, weighing from two to four and a half tons, quarried at the site and bedded in a cement mortar. The roughly rectangular blocks were bedded on and packed with sandstone concrete, with cement mortar only being used where considered necessary. The concrete is made with crushed Hawkesbury sandstone. Concrete made of hard basaltic stone (instead of the softer sandstone) is used for the upstream face, 2 feet (0.6m) thick, which merges into sandstone concrete 6 feet (1.8m) thick at lower levels and 4 feet (1.2m) thick at higher levels. The dam wall is curved in plan and has a bywash spillway as a continuation of its southern end. Each end of the dam wall is flanked by massive Egyptian style pylons complete with decorative lotus columns. These pylons differ from those at Avon Dam by having heavy fluting to the lotus columns. Two valve houses along the dam wall are square, flat-roofed concrete buildings with strong Egyptian stylisation in the tapered wall profiles, circular beading to corners and overhanging eaves. These contain discharge outlets, with the Upper Outlet consisting of two 48 inch (1.2m) pipes with FCD valves and Ring Faulkner gate valves. The two lower valve houses at the downstream foot of the dam wall are very similar in appearance and which contain 36 inch (0.9m) discharge pipes with Ring Faulkner gate valves and scour valves as outlets.

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 90 feet (27.4m); inspection galleries at upper and lower levels, together with piping for registering any ground water pressure.

Specifications for Cordeaux Dam
Total capacity: 20,597 million gallons (93,716 million litres).
Greatest depth of water: 170 feet (51.8m).
Greatest height of wall: 191 feet (58.2m) (above foundations).
Length of crest including pylons: 1,327 feet (404.6m).
Area of lake: 1,931 acres when full (782.0ha).
Top water level 996 feet (303.6m) above mean sea level.
Completed in 1926.
Cost: £945,000 ($1,908,000).
Concrete in wall: 281,440 cubic yards (167,106.6 cm).
Length of spillway weir: 500 feet (152.4m).
Width of crest: 16.5 feet (5m).
Width of base: 150 feet (45.7m).

Cordeaux Dam storage is discharged to the Cordeaux River downstream, flowing to Pheasants Nest Weir on the Nepean River where it is diverted through a tunnel 4.5 miles (7.2km) long to the Cataract River at Broughton’s Pass. From here it is diverted by another weir to the Cataract Tunnel, 2 miles (3.2km) long, emerging into the Upper Canal by which it is conveyed to Prospect Reservoir.

There are three cottages associated with the Dam, two of brick and one of weatherboard. The brick cottages are both very similar single-storey brick bungalows with terracotta-tiled hipped-gable roofs, dating from the 1960s. The weatherboard cottage appears to date from the construction of the Dam and is reputed to have been the Resident Engineers residence. It is a single-storey, weatherboard clad building on sandstone piers with a hipped and gabled roof clad in corrugated-iron. The building features little decoration but has a front verandah which wraps around the building for half the length of the sides. This has chamfered square timber posts, a slatted timber balustrade and sandstone steps with sandstone masonry balustrades.

The Cordeaux Dam site is a popular tourist attraction. The public area is maintained with picnic grounds, landscaped gardens, shelter sheds and pathways. The grounds associated with the main public areas of the dam contain many intact landscape elements from the circa 1930s (and possibly late 1920s). Remnant landscape features include stone retaining walls; gardens (layout and plantings); a robust and imaginative cement-sculpted grotto/picnic shelter sited between a large Monterey Pine and a very large Eucalypt; a broad stone flagged surface drain in the upper picnic area; a lower picnic area with a series of grassed terraces accessable by a narrow crazy-paved path in stone; and a Monterey Pine (Pinus radiata) avenue to the lower dam road with gums beyond. The upper park area is characterised by mature pines while an interwar cottage and nearby propagating structure include older plantings of Magnolia grandiflora and Lagerstroemia indica which are probably contemporary with the cottage. A distinctive feature of the site is stands of autochthonous Cypress Pine (Callitris sp.).

The Conservation Management Plan outlines the key elements and their individual significance assessments.
Physical condition and/or
Archaeological potential:
Date condition updated:21 Jan 09
Modifications and dates: 1960's - Two brick cottages were built , probably as replacements for earlier weatherboard cottages.
1988 - Upgraded with a system of drains in the wall and foundations.
Further information: Cordeaux Dam is located in three Council areas: Wollondilly, Wingecarribee and Wollongong.
Current use: Water Supply
Former use: Water Supply


Historical notes: Soon after the completion of Cataract Dam it was identified that more storage was required for Sydney. Low rainfall on the catchment between 1907 and 1911, coupled with a greatly increased demand for water stressed the necessity for extra water for the growing population. In 1911 the Board selected a site for the dam on the Cordeaux River and a gauging weir was constructed. Preliminary plans and estimates were prepared and the foundations were tested.

Over the next few years good rainfall kept the storage levels in Cataract Dam at satisfactory levels, and this along with the intervention of World War I, delayed any major construction work on the dam site until 1918.

In November 1918 a Board of Experts was appointed by the Government to draw up recommendations for the amplification of the Sydney water supply. The Board recommended the construction of not only Cordeaux, but also of Avon and Nepean Dams, which were proceeded with in turn.

Cordeaux Dam was built by the Department of Public Works, with the design being supervised by the Chief Engineer for Water Supply and Sewerage, E.M. de Burgh, who was also responsible for the construction.

During construction, local Hawkesbury sandstone was quarried and dressed on site into the necessary sized blocks. Because the stone was easily quarried into large blocks, cyclopean masonry was the preferred construction method, with the blocks being bedded on and packed with sandstone concrete. The concrete was made with the Hawkesbury sandstone crushed to 2.5 inch gauge, cement mortar being used only when deemed necessary.

Concrete made from harder basalt stone was used on the upstream face two feet thick, merging into sandstone concrete six feet thick at lower levels and four feet thick at higher levels. Cement and basalt were bought to the construction site by three miles of steam operated aerial ropeway. Much of the plant was electronically operated with power being supplied from the State Power Station at Port Kembla via transmission lines.

The workers were accommodated within the vicinity of the dam in barracks or cottages depending on their marital status, with the Public Works Department assisting in the construction of temporary homes for the married men and their families.

The dam was completed in 1926 and handed over to the Metropolitan Water Sewerage and Drainage Board on February 3rd, 1927. The dam showed a number of improvements in design and construction from the earlier Cataract Dam, including contraction joints between units of construction placed at regular intervals, inspection galleries at upper and lower levels, together with piping to register any ground water pressure.

In December 2016 the state government approved the controversial South32 Dendrobioum coal mine in the Metropolitan Special Areas, created to protect the waters of Cordeaux, Avon, Cataract and Nepean Reservoirs (Hannam, 2016, 14).

Historic themes

Australian theme (abbrev)New South Wales themeLocal theme
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 industrial production-
3. Economy-Developing local, regional and national economies Technology-Activities and processes associated with the knowledge or use of mechanical arts and applied sciences (none)-
4. Settlement-Building settlements, towns and cities Utilities-Activities associated with the provision of services, especially on a communal basis (none)-
4. Settlement-Building settlements, towns and cities Utilities-Activities associated with the provision of services, especially on a communal basis (none)-
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 (none)-
7. Governing-Governing Defence-Activities associated with defending places from hostile takeover and occupation Involvement with the Second World War-
8. Culture-Developing cultural institutions and ways of life Leisure-Activities associated with recreation and relaxation (none)-

Assessment of significance

SHR Criteria a)
[Historical significance]
Cordeaux Dam is constructed 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. Cordeaux Dam is the second of these dams to have been completed. The Upper Nepean Catchment Area continues to supply the regions of Sydney and Illawarra.

Cordeaux Dam was the fourth of the major water supply dams constructed in NSW during the first half of the twentieth century. The design and technologies used in the construction of the dam are representativethe methods developed by the Public Works Department of NSW at the time.

In conjunction with the completion of Avon Dam in 1927, the impounded water of the Cordeaux catchment area provided one of the major sources of water for domestic and industrial consumption in metropolitan Sydney, the largest city in New South Wales. 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 1920s and 1930s.
SHR Criteria b)
[Associative significance]
The design and construction of Cordeaux Dam was undertaken by the Water Supply and Sewerage Branch of the NSW Public Works Department. The construction of the dam drew upon the knowledge and experience of a number of engineers employed in the Branch at the time, including Ernest M. de Burgh (Chief Engineer). The successful completion of the dam and its continuation of use as a water supply dam are a lasting testament to the professional capabilities of the Federation/Inner War era generation of engineers of the Public Works Department.

The tract of Eucalyptus bordering the encircling road of the upper picnic area was planted out by Board members of the former Water Board in 1928. The trees have particular memorial associations with past identities of the Board.
SHR Criteria c)
[Aesthetic significance]
The wall of Cordeaux Dam is an engineering work imbued with a sense of aesthetic values expressed through the long curved wall set within the valley of the Cordeaux River.

The design and finishes of the crest houses, entry pylons and lower valve houses in the Inter Egyptian style were undertaken by the Government Architect's branch of the Public Works Department at the time headed by George McCrae. The architectural detailing evokes a romanticised version of the Ancient Near East at a time when many Australians had first hand experience of the area through military service, and through knowledge of archeological finds reported in the popluar press.

The dam is set within the valley of the Cordeaux 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 gorgre created by the river's flow over time. Collectively this topography at times of high water imparts a picturesque scene when viewed from selective 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 accomodation provided for 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 signficance 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 signficance to NSW in relation to its historical, scientific, cultural, social, archaeological, natural and aesthetic values.
SHR Criteria e)
[Research potential]
The cyclopean masonry of the dam is an excellent early example of gravity dam construction in the Inter War era. It incorporates inspection galleries, contraction joints, and foundation drainage systems which collectively demonstrate the advanced state of this technology at the time.

Terraces and platforms adjoining the dam abutments demarcate the location of plant and equipment used in in the construction of the dam, in particular the location of the cableway head towers, and concrte batching plant. The plateau of the upper picnic area was the site of the original construction township and retains a road formation, culverts and drainage lines and tennis court from that era.

The grounds of the dam retain numerous tree plantings undertaken for the opening of the dam in 1927. Collectively the diversity of these trees present a good record of past horticultual practices.
SHR Criteria f)
The wall of the Cordeaux Dam is the longest of all the dams constructed in the Upper Nepean Catchment Area. Cordeaux Dam is one of three dams in NSW which incorporate extensive inter War Egyptian architectural detailing. Cordeaux Dam is one of two extant dams in NSW which incorprate pedestrian and vehicular entry pavillions to the crest wall.

The crest and valve houses and inlet works retain original ironwork and machinery such as roller gates, penstocks and penstock opening sysyem which represent a substantial repository of water supply delivery technology for the era in NSW.

The dam incorporates the first instance of multiple level water discharges and valve houses, and emergency roller gates in NSW. The ensemble of plant buildings either asscociated with the construction or completion of the dam, such as weatherboard machine shed (adapted to double garage) and the corrugated iron blacksmiths, are unique in situ examples within the broader context of the four Metropolitan Dams.

The dam incorprates cyclopean masonry which is a construction technique unique to the Metropolitan Dams in Australia. The dam incorptates the first instance of internal inspection galleries and connecting pipework and V notch weirs in a dam in NSW.
SHR Criteria g)
Cordeaux Dam is representative of a type of dam (cyclopean masonry gravity dam) constructed in NSW by the Department of Public Works during the first half of the twentieth century. Key representative attributes of the dam design and construction include the use of cyclopean masonry bedded in sandstone concrete, use of blue metal concrete in facing the upstream face, the use of sandstone concrete in facing the downstream wall, use of a spillway that is an extension of the gravity wall, upper and lower valve/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 galleries, the foundation grouting system, the contraction joints, and the internal drainage system.

The upgrading of the valves within the dam wall and ancillary monitoring and operating equipment is representative of modern day safe operating practice.

The construction technologies used at Cordeaux Dam are representative of dams constructed in NSW through the first half of the twentieth century. Key representative attributes include the the use of cableways, the building of temporay townships to house labourers and tradesman, building of semi-permanent cottages to house salaried staff, the construction of terrace 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, men and horses and the use of electricty to power plant and equipment.

The rehabilitation of tracts of land scarred in the construction processes employed at Cordeaux Dam through beautification works is representative of pratices undertaken at other dams throughout NSW. Key representative attributes of this practice include utilising the former township as a picnic area, utilising the former terraced construction areas as picnci areas and lookouts, and utilising the former construction roads and tramway for vehicular access to the dam wall.

The practice of ongoing maintenance of the wall after completion through surveillance provided by resident staff and workshop facilities is representative of procedures undertaken at other dams 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 fabric of Cordeaux Dam retains a high level of integrity.
Assessment criteria: Items are assessed against the PDF 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: Prepare a maintenance schedule for the item(s) in Maximo. Recommended Management: Implement the Conservation Management Plan (Graham Brooks & Assoc., 2003). 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.

Procedures /Exemptions

Section of actDescriptionTitleCommentsAction date
21(1)(b)Conservation Plan submitted for endorsementMetropolitan Dams, NSW: Conservation Management Plan (Graham Brooks and Associates, Feb 2002) CMP endorsed by Heritage Council 27 June 2003 for a period of five years, expires 27 June 2008. Jun 27 2003
57(2)Exemption to allow workStandard Exemptions SCHEDULE OF STANDARD EXEMPTIONS
Notice of Order Under Section 57 (2) of the Heritage Act 1977

I, the Minister for Planning, pursuant to subsection 57(2) of the Heritage Act 1977, on the recommendation of the Heritage Council of New South Wales, do by this Order:

1. revoke the Schedule of Exemptions to subsection 57(1) of the Heritage Act made under subsection 57(2) and published in the Government Gazette on 22 February 2008; and

2. grant standard exemptions from subsection 57(1) of the Heritage Act 1977, described in the Schedule attached.

Minister for Planning
Sydney, 11 July 2008

To view the schedule click on the Standard Exemptions for Works Requiring Heritage Council Approval link below.
Sep 5 2008

PDF Standard exemptions for works requiring Heritage Council approval


Heritage ListingListing TitleListing NumberGazette DateGazette NumberGazette Page
Heritage Act - State Heritage Register 0136018 Nov 99   
Heritage Act - s.170 NSW State agency heritage register 125220   
Local Environmental PlanCordeaux dam and pumping station 23 Aug 91   
National Trust of Australia register Cordeaux Dam Wall Including Bywash And Valve House192023 Sep 85   

Study details

TitleYearNumberAuthorInspected byGuidelines used
Sydney Water Heritage Study1996125220Graham Brooks and Associates Pty LtdGRAHAM BROOKS AND ASSOCIATES PTY LTD 1 July 1996 Yes

References, internet links & images

TypeAuthorYearTitleInternet Links
Tourism 2007Cordeaux Dam View detail
WrittenAird W. V.1961The Water Supply, Sewerage and Drainage of Sydney
TourismAttraction Homepage2007Cordeaux Dam View detail
WrittenAustralian Museum Business Services2008Statement of heritage impact: Cataract, Cordeaux & Nepean Dams: Environmental Flow Releases for the Upper Hawkesbury-Nepean River
WrittenBeasley M.1988The Sweat of their Brows - 100 Years of the Sydney Water Board 1888 - 1988
WrittenGraham Brooks and Associates2003Cordeaux Dam Conservation Management Plan
WrittenHannam, Peter2016'Controversial South32 mine wins nod' - Mining: concerns for Ground Water
WrittenNick Jackson, Matthew Taylor, Jon Breen2003Metropolitan Dams Conservation Management Plan Vol.3, Cordeaux Dam
WrittenSimpson M.1985Cordeaux Dam Wall

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

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Data source

The information for this entry comes from the following source:
Name: Heritage Office
Database number: 5051470
File number: H08/00191; H99/00197, 125220

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.

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