Completed in 1926 under the supervision of Ernest Macartney de Burgh, the dam is owned by Water NSW, an agency of the Government of New South Wales.

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.

From here it was conveyed by aerial ropeway across the Nepean Gorge to an interchange on the eastern side where the material was transferred to a 2 ft (610 mm) gauge steam tramway to a point adjacent to the dam site.

Each end of the dam wall is flanked by massive Egyptian style pylons complete with decorative lotus columns.

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.

From here it is diverted by another weir to the Cataract Tunnel, three-point-two-kilometre (two-mile) long, emerging into the Upper Canal by which it is conveyed to Prospect Reservoir.

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 accessible by a narrow crazy-paved path in stone; and a Monterey Pine (Pinus radiata) avenue to the lower dam road with gums beyond.

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.

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.

[1] 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.

The design and construction of Cordeaux Dam was undertaken by the Water Supply and Sewerage Branch of the NSW Public Works Department.

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 popular press.

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 times of high water imparts a picturesque scene when viewed from selective vantage points above and on the dam wall.

It incorporates inspection galleries, contraction joints, and foundation drainage systems which collectively demonstrate the advanced state of this technology at the time.

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.

[1] The dam incorporates the first instance of multiple level water discharges and valve houses, and emergency roller gates in NSW.

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.

Key representative attributes include the use of cableways, the building of temporary 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 electricity to power plant and equipment.

[1] 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.