Celebrating 100 years of catchment protection

Metropolitan Special Area celebrates 100th anniversary

Metropolitan Special Area protects Upper Nepean dams

That Greater Sydney enjoys some of the highest quality drinking water in the world is because of a remarkable series of firsts, one of which celebrates its 100th anniversary this year.

The Metropolitan Catchment Area was proclaimed in 1923 to protect the water that flowed into the Nepean, Avon, Cordeaux and Cataract rivers above Pheasants Nest and Broughton Pass weirs that at the time supplied most of Sydney’s water.

Covering 90,239 hectares on the Woronora Plateau south of Sydney, and later re-named the Metropolitan Special Area, it is believed to be one of the longest-standing drinking water catchment protection areas in Australia.

The Metropolitan Special Area was designed to protect the water quality of an even more remarkable first – the Upper Nepean scheme.

The visionary scheme in the late 1800s helped solve Sydney’s water supply problems by collecting water from where it rained frequently and heavily south of Sydney, and transferring that water to Sydney to provide a reliable supply.

It was the first time in Australia that water was collected well away from a city, transported by canals and pipelines, and stored in a major dam (Prospect Reservoir).

A Royal Commission after the Federation Drought of 1901-02 expanded the Upper Nepean system by building four new dams: Cataract (completed 1907), Cordeaux (1926), Avon (1928) and Nepean (1935).

Throughout the past 100 years the water that flows into those dams and weirs has been protected by the native bushland and upland swamps of the Metropolitan Special Area. Today, it is a haven for native flora and fauna, including many threatened or endangered species.

Cordeaux Dam and catchment
Completed in 1926, Cordeaux Dam is remarkable for its Egyptian inspired architecture, with massive Egyptian style stone gateways guarding the entrance to the dam wall.
Upland swamp
There are over 1000 uplands swamps on the Woronora Plateau. Water flows through this patchwork of swamps, helping purify the water and store it to be slowly released.

Multi-barrier approach to protect water quality

Special Areas cover 364,778 hectares of land that surrounds and protects water supply storages for more than 5 million people of Sydney and the Illawarra, Blue Mountains, Southern Highlands, Goulburn and Shoalhaven regions.

WaterNSW manages the Special Areas to reduce risks to water quality, protect and prevent the environmental degradation, and conserve cultural values.

More Special Areas followed the successful creation of the Metropolitan Special Area in 1923 (amended 1933): Woronora Special Area (established 1941), Warragamba (1942), Shoalhaven (1970), Fitzroy Falls (1973), Wingecaribee (1973), Blue Mountains (Blackheath, Katoomba, Woodford, 1991), and Prospect (2008).

“WaterNSW is proud to jointly manage the Metropolitan and other Special Areas that protect Greater Sydney’s drinking water catchments, in partnership with the NSW National Parks & Wildlife Service, and our neighbours and stakeholders,” WaterNSW Executive Manager Strategy & Performance, Fiona Smith, said.

The Special Areas are part of a multi-barrier approach to address risks to water quality throughout the whole of the water supply chain, from the raw water source in the catchment, water storages and transfer systems through to treatment plants and delivery systems to customers’ taps.

“The multi-barrier approach recognises that while each individual barrier may not be able to completely remove or prevent contamination all of the time, they collectively provide greater assurance that the water supply will be safe,” Fiona said.

The Special Areas also protect a rich and diverse range of Aboriginal heritage sites and values in a relatively undisturbed landscape setting, and historic heritage features such as early infrastructure associated with roads, water supply, farming and mining.

The health of Sydney’s Drinking Water Catchment is independently audited every three years. While the latest audit found that recent climate-driven events, including severe drought, bushfires and subsequent heavy rainfall events have had a negative influence on catchment health, the audit also found that actions taken by agencies such as WaterNSW in partnership with industry and the community have reduced many hazards to catchment health. These actions include restoration and rehabilitation of the natural environment, and policy and decision-making backed by sound evidence.

NSW Govt Gazette 1923
NSW Government Gazette No. 79 on 13 July 1923 proclaimed the establishment of the Metropolitan Catchment Area, by the order of His Excellency's Command, R.T. BALL. GOD SAVE THE KING!
Metropolitan Catchment 1928
The valley of the Cataract River before construction of Cataract Dam began in 1902, located in the Metropolitan Catchment, declared a Special Area in July 1923 (State Library PXA 101-4).

100th anniversary of Metropolitan Special Area

This year is the 100th anniversary of the declaration of the Metropolitan Special Area on July 13, 1923.

Although the catchment areas were secured by other legislation from 1888 by the Board of Water Supply and Sewerage (1888-1892) and Metropolitan Board of Water Supply and Sewerage (1892-1925), there was no formal protection until 1923.

On 13 July 1923 the NSW Government Gazette No. 79 proclaimed:



I, Sir Walter Edward Davidson, the Governor of the State of New South Wales and its Dependencies, in the Commonwealth of Australia, in pursuance of the provisions of the Metropolitan Water and Sewerage Acts, 1880-1922, do, by this my Proclamation, revoke and cancel the Proclamation of the Metropolitan Catchment Area, published in pursuance of section twenty-seven of the Metropolitan Water and Sewerage Act. 1880, in the Government Gazette of sixth July, one thousand eight hundred and eighty, and do hereby proclaim and define the boundaries as described in the Schedule hereto to be the boundaries of the Metropolitan Catchment Area for the purpose of supplying water for the City of Sydney and its suburbs and places and districts served from such supply.

[Misc. 1923-2,477]

Signed and sealed at Sydney, this twenty-seventh day of June, 1923.

By His Excellency's Command,




All that piece or parcel of land in area about 347 and a half square miles, situated in the parishes of Appin, Wedderburn, and Southend, county of Cumberland, and parishes of Bargo, Banksia, Dendrobium, Wilton, Wallandoola, Wonona, Cordeaux, Kembla, Wongawilli, Burke, Calderwood, Kangaloon, Mittagong, and Colo, county of Camden, State of New South Wales, as defined on plan catalogued Ms. 2,286 Sy. (eight sheets) deposited at the Department of Lands, Sydney.

Published date: 21 August 2023

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