It is a concrete gravity dam, which creates Lake Burragorang, the primary reservoir for water supply for the city of Sydney.

The dam was devised as part of a collective engineering response to Sydney's critical water shortage during World War II and was originally known as the Warragamba Emergency Scheme.

[4] In 1845, Paweł Strzelecki drew attention to the Warragamba River as a water supply catchment; in 1867, supporters proposed a dam.

[5] 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.

[5] In 1910, Ernest de Burgh, Chief Engineer for Water Supply and Sewerage, in the NSW Public Works Department prepared a proposal for a dam on the Warragamba River and followed it up in 1918 with more detailed plans.

Major elements of the construction works still extant include the weir, a 10-cable cableway, shads, batching plants, roads, electrical substation, chlorination plant, maintenance staff accommodation, balance reservoir, Megarritys Bridge, water pumping station, tunnels, and associated pipelines.

[4] In 1943 the Metropolitan Water, Sewerage and Drainage Board invited the geologist William Browne to investigate a proposed site.

[7] The site was reviewed and approved by Dr John Savage, considered the pre-eminent expert in this field, and formally accepted by the Metropolitan Water, Sewerage and Drainage Board on 2 October 1946.

This river configuration allows for a relatively short but high dam wall, in the gorge, to impound a vast quantity of water.

The resulting dam of the Warragamba River formed Lake Burragorang, which is one of the largest reservoirs for urban water supply in the world.

It was laid as interlocking blocks roughly 17 metres (56 ft) on each side, which were later grouted together to form a continuous, monolithic wall.

[9] There was also a hydroelectric power station at the dam that could generate 50 megawatts (67,000 hp),[11][12] transmitting its output over a 132 kV transmission line to a Penrith Substation.

[citation needed] Since 2017, WaterNSW has been working on a risk-mitigation project, aimed at protecting human life and property in the floodplain catchment area in case of major flooding, primarily by raising the dam wall by up to 17 metres (56 ft).

[14] Infrastructure NSW's rationale is based on the fact that up to 134,000 people live and work on the floodplain, and urban growth could greatly increase this number in decades to come; giving the dam a greater capacity would enable holding back floodwaters before releasing it in a controlled fashion, reducing the need for urgent evacuations.

The box gum grassy woodlands are home to threatened species of birds, including up to 50% of the remaining population of the critically endangered regent honeyeater, as well as koalas and greater gliders.

[16] The federal review also said that the environmental impact assessment lacked detail on how the project could affect species such as the platypus and echidna.

[20] The New South Wales State Government tried to reduce this risk by implementing water restrictions[21] and commissioned the construction of a desalination plant, at Kurnell.

[22] On 30 February 2012, it was reported that the dam was likely to overflow for the first time in fourteen years, due to continuing heavy rain in the region.

[27] Warragamba Dam was a popular picnic spot for Sydneysiders, but access to the public was restricted after 1999 due to A$240 million of upgrades in that time.

The Emergency Scheme is representative of the collective engineering response to Sydney's critical water shortage during the Second World War period.

All of the components are excellent examples of the civil engineering skills of the times; the Balance Reservoir is particularly significant because it provides a stilling pool downstream of Warragamba Dam for the purpose of flood discharge; the group of five cottages associated with the construction of the dam are considered to be of high significance because they housed the operations staff between 1940 and 1959.