City Tunnel

  • Number
    4574202
  • Primary address

    201, Potts Hill Reservoir to Dowling St Pumping Station Potts Hill to Waterloo, . NSW
    LGA: Marrickville
    LGA region: Sydney
    DUAP region: Sydney South

  • Alternate Address

    37, Potts Hill Reservoir to Dowling St Pumping Station Potts Hill to Waterloo, . NSW
    LGA: Bankstown
    LGA code: BANK
    LGA region: Sydney
    DUAP region: Hunter & Central Coast

  • Owner
    Sydney Water
  • Current use
    Supply of large volumes of water to city, especially the east and south-east.
  • Former use
    Water Supply
  • Item type
    Built
  • Item group
    Utilities - Water
  • Item category
    Water Tunnel
  • Curtilage/Boundary
    The physical and operational curtilage is limited to the tunnel and any access chambers and supporting or associated structures from its original construction. The physical curtilage of the City Tunnel is to be taken as a distance of 3 metres around the existing infrastructure. The infrastructure associated with this item includes the tunnel, vertical shafts and the buildings attached to the shafts.
  • Statement of significance
    The City Tunnel in its function largely is a duplicate of the Pressure Tunnel. It supplies water from Potts Hill to the city. The need for an additional pipeline was recognised in the early 1940's and it has been used in conjunction with the original Pressure Tunnel. The City Tunnel has made maintenance of the supply easier due to Sydney Water's ability to close sections of either tunnel for inspection and maintenance. It has increased the supply of water to the eastern and southern suburbs of Sydney. The City Tunnel has little cultural landscape value as it is located entirely below ground. The physical and operational curtilage is limited to the tunnel and any access chambers and supporting or associated structures from its original construction. The physical curtilage of the City Tunnel is to be taken as a distance of 3 metres around the existing infrastructure. The infrastructure associated with this item includes the tunnel, vertical shafts and the buildings attached to the shafts.
  • Endorsed significance
    Local
  • Designer
    Sydney Water Board
  • Builder
    Sydney Water Board
  • Year started
    1946
  • Year completed
    1961
  • Circa
    No
  • Physical description
    The tunnel begins at Potts Hill and passes under Chullora, Bankstown, Enfield, Canterbury, Ashfield, Petersham, Marrickville, Erskineville and Waterloo at depths varying between 15 and 67 metres. There are cross connections between the City Tunnel and the Pressure Tunnel. The tunnel is 2400mm and 3100mm in height, steel lined and 14 km in length. The City Tunnel was constructed by digging a tunnel, laying fully joint welded steel pipes, with the annular spaced filled with blue metal concrete. The pipes were internally cement lined during manufacture. It represented the latest in tunnelling technology of the time. The physical curtilage of the City Tunnel is to be taken as a distance of 3 metres around the existing infrastructure. The infrastructure associated with this item includes the tunnel, vertical shafts and the buildings attached to the shafts.
  • Modifications made
    N/A
  • History
    With the Pressure Tunnel running to full capacity it became necessary for a second tunnel from Potts Hill to the city. In 1943 the Board gave priority to the construction of a second tunnel, and approved the construction of this tunnel in 1946. In that same year excavation began on shaft 5. By 1949 all the shafts except for shaft 13 were excavated. In 1952 work on the tunnel was suspended due to lack of funds but recommenced in 1953. Lining of the tunnel began in 1954. Two years later the tunnel was completed and the first section between Potts Hill and Ashfield (shaft 7) was commissioned in 1957. The safety of the workers was of utmost importance. A safety committee was set up and met monthly. Constant examination of the tunnel was employed to ensure worker safety.
  • National
    Economy
  • State
    Technology
  • Local
    (none)
  • National
    Settlement
  • State
    Utilities
  • Local
    Water Supply
  • Local description
    Relates to the planning, development, expansion and provision of water supply.
  • a) Historical
    This was one of Sydney Water's major post-WW2 projects. It utilised Returned Service personnel and recently arrived migrants, especially from Europe.
  • c) Aesthetic
    Only the access shafts are visible from the surface. They are less decorative than the 1930's Pressure Tunnel structures.
  • d) Social
    The tunnel is socially significant as it provided great volumes of drinking water to the residents of the city suburbs and is likely to be held in high regard by the community for the functions it plays.
  • e) Research
    Despite post-WW2 shortages, this was a copy book job. It made use of the relatively new process of "rockbolts" particularly in dealing with shale layers. It also allowed for future operation and maintenance of the system, whereby it can alternate with the Pressure Tunnel at times of low demand. With the tunnel being steel-lined conduit and fully welded it would be possible to boost supply in future years.
  • f) Rarity
    It is one of a handful of significant larger tunnels built as part of Sydney's water supply system. It was one of Sydney's major post-war projects.
  • g) Representative
    Representative of a number of large pipelines built since WW2. However this was built by the "drill and blast" method. More recent tunnels involved tunnel boring machines.
  • Integrity assessment
    Substantially intact.
  • List name
    Heritage Act - s.170 NSW State agency heritage register
  • Date listing listed
    01 January 2000
  • City Tunnel - Jumbo Drill in Tunnel at Shaft 5
    City Tunnel - Jumbo Drill in Tunnel at Shaft 5
    Created by: Sydney Water
    Creation date: 01 January 2055
  • Location of the City Tunnel - from '''The Water Supply, Sewerage and Drainage of Sydney''
    Location of the City Tunnel - from '''The Water Supply, Sewerage and Drainage of Sydney''
    Created by: W.V. Aird
    Creation date: 01 January 2061
  • Longitudinal Section of City Tunnel and Shafts
    Longitudinal Section of City Tunnel and Shafts
    Created by:
    Creation date: 01 January 2058
  • Data entry status
    Basic
  • Entered
    01 December 2000
  • Updated
    18 March 2014