Mosman Bay Sewage Aqueduct | NSW Environment, Energy and Science

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Mosman Bay Sewage Aqueduct

Item details

Name of item: Mosman Bay Sewage Aqueduct
Other name/s: Aqueduct over Mosman's Bay
Type of item: Built
Group/Collection: Utilities - Sewerage
Category: Sewage Aqueduct
Location: Lat: -33.8346252042 Long: 151.2333882750
Primary address: Avenue Road, Mosman, NSW 2088
Local govt. area: Mosman
Local Aboriginal Land Council: Metropolitan
Property description
Lot/Volume CodeLot/Volume NumberSection NumberPlan/Folio CodePlan/Folio Number
PART LOT1 DP172712
PART LOT7078  93732


Curtilage includes the sewage aqueduct support, part carrier and part footbridge. It excludes the two small pipes and paving of the pedestrain bridge, both c.1970 installations.
All addresses
Street AddressSuburb/townLGAParishCountyType
Avenue RoadMosmanMosman  Primary Address
Park AvenueMosmanMosman  Alternate Address


Organisation NameOwner CategoryDate Ownership Updated
Sydney WaterState Government27 Nov 98

Statement of significance:

The Mosman Bay Aqueduct over Reid Park completed in 1901 is a magnificent piece of Federation era engineering constructed from imported steel. It is one of two such structures in Sydney Water's portfolio of assets, which as a type are unique in New South Wales . The aqueduct was designed to provide the conveyance of sewerage over the bay as part of the Neutral Bay and Mosman branch sewerage scheme, one of the earliest of the lower north shore sewerage schemes constructed from 1891. The structure is a key element in the historic built environment of the lower north shore, and continues to serve as a pedestrian right-of-way. The structure forms an intrinsic element of the landscaping of Reids Park. Elements of significance are past and ongoing use, technology of construction, the shape of the arch, and setting within the park (inclusive of views).
Date significance updated: 21 Apr 05
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: Sewerage Construction Branch, Department of Public Works
Builder/Maker: Department of Public Works
Construction years: 1899-1901
Physical description: An arched steel aqudeuct built for the purpose of enabling water mains to be carted over a gully, linking Avenue Road and Bay Street Mosman. The single span steel arch aqueduct currently carries three pipes. Two 500mm mild steel cement lined pipes laid between 1968 and 1971 and a 600mm mild steel cement lined pipe which replaces a rivetted original with the same diameter. The fix ended steel arch has a span of 42.68m with arch members being '18inches x 7 inch x 75lbs per ft.' A pedestrian walkway was built along the top of the pipes and the arch now serves a dual purpose.
Modifications and dates: Intact and in good condition. In 1968, maintenance and up-grading works were commenced and consisted of the addition of 2530mm pipes and the replacement of the slats of the timber footbridge with concrete block paving.
Further information: Johnson's Creek Aqueduct
Current use: Public footbridge and sewage aqueduct
Former use: Sewage Aqueduct


Historical notes: The sewage aqueduct over Reid Park at the head of Mosman Bay was partially completed by 1901 (and fully completed by 1904) as part of the Neutral Bay and Mosman branch sewerage scheme. The sewer originally discharged into the Folly Point (Primrose Park) sewerage treatment plant. This was one of the earliest of the lower north shore sewerage schemes, which were constructed between 1891 and 1898. The bridge was designed in the Sewerage Construction branch of the Department of Public Works in June 1899. The engineer-in-chief of this department was Joseph Davis. The design provided for an aqueduct to ‘connect the second and third divisions of this sewer where it crosses the tidal waters at the head of Mosman Bay’. The design of a steel parabolic arch of 140-ft (42.6 m.) span was evidently determined by need to provide a structure ‘in such a way as to be no disfigurement to the locality (and) for convenience of foot passengers, a bridge will be built on top of the aqueduct.’ The aqueduct is one of two examples of a steel arch aqueduct constructed in Sydney for sewerage and water supplies (another carried the rising water main from Ryde to Chatswood reservoir over the Lane Cove River, in the second bridge on that site.) It is the only aqueduct with pedestrian access. The steel use in the construction of the aqueduct was imported from England. Due to delays encountered in the delivery of this material construction work did not commence until 1900. The aqueduct was originally fitted with one 2-ft. (0.6 m) diameter riveted steel pipe. In 1926 the Neutral Bay and Mosman branch sewer was connected to nearly completed Northern Suburbs Ocean Outfall Sewer. The original riveted steel 2-ft. (0.6 m) diameter pipe was replaced with a welded steel pipe in 1937. An additional two 20-in (0.53 m) mild steel pipes were laid in 1971. Also at this time the timber slat paving of the pedestrian bridge was replaced in concrete blocks. The Mosman sewage aqueduct (1901) is one of six sewage aqueducts in Sydney completed in the period 1895-1901. Others include the reinforced concrete ‘Monier’ arches at Whites Creek and Johnstons Creek (1897), the mass concrete/brick arches and iron pipe at Wolli Creek and Cooks River (1895), the Lewisham concrete/stone pier and steel oviform carrier (1900).

Historic themes

Australian theme (abbrev)New South Wales themeLocal theme
4. Settlement-Building settlements, towns and cities Utilities-Activities associated with the provision of services, especially on a communal basis (none)-

Assessment of significance

SHR Criteria a)
[Historical significance]
The aqueduct was designed to provide the conveyance of sewage over Mosman Bay as part of the Neutral Bay and Mosman branch sewerage scheme, one of the earliest of the lower north shore sewerage schemes constructed from 1891.
SHR Criteria c)
[Aesthetic significance]
The Mosman Bay Aqueduct over Reid Park completed in 1901 is a magnificent piece of Federation era engineering purposely and attractively set within a public reserve.
SHR Criteria d)
[Social significance]
The structure is a key element in the historic built environment of the Mosman area, and continues to serve as a pedestrian right-of-way. The structure is listed by authorities such as the National Trust of Australia (NSW).
SHR Criteria e)
[Research potential]
The bridge structure incorporates an extensive quantity of imported steel work, which is likely to be rare for this date outside of railway construction.
SHR Criteria f)
The use of a steel supporting structure with pedestrian bridge is rare; another example is the aqueduct over the Lane Cove River. Collectively these two bridges are rare in NSW as a type.
SHR Criteria g)
The siting of the aqueduct within a reclaimed public reserve is representative of other items of Water Board infrastructure located on the lower north shore.
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.

Procedures /Exemptions

Section of actDescriptionTitleCommentsAction date
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 0132818 Nov 99   
Heritage Act - s.170 NSW State agency heritage register 115046   

Study details

TitleYearNumberAuthorInspected byGuidelines used
Sydney Water Heritage Study1996115046Graham Brooks and Associates Pty LtdGRAHAM BROOKS AND ASSOCIATES PTY LTD 1 July 1996 Yes

References, internet links & images


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Data source

The information for this entry comes from the following source:
Name: Heritage Office
Database number: 5051429
File number: H05/00106

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