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Drainage Services Department
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OUf VISION is to provide world-class wastewater and stormwater drainage services enabling the sustainable development of Hong Kong
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BACKGROUND
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Most of the existing drainage systems of
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the lower catchment of Nor t hern Hong
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Kong Island were built decades ago. The
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protection standards are no longer adequate
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t o co pe w ith the requirement of rapid
urbanization and changes in land use over
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the years. During heavy rainstorms . huge
flows run alo ng paved areas and down to
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the low- lying urban areas, ca using floods
and disturbance to traffic and business.
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The traditional approach to improve the
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drainage systems in urbanized areas is to
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construct additional drains. However, this
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en large the existing drainage system or
will require extensive road openings in busy
roads causing serious traffic disruption s
and environmental nuisances. A drainage
tunnel scheme is considered to be a better
approach to intercept the surface runoff in
mid - hi ll for discharge into the sea without
passing through the downstream drainage
systems. This wi ll greatly reduce the extent
of pipe-laying works and relieve the flood
hazard in the downstream built-up areas.
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SCOPE OF WORK
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The Hong Kong West Drainage Tunnel is
a government's major initiative to relieve
the flooding problem in Northern Hong
Kong Island. It consists of a ma in tunnel
to be built deep underground in Mid-levels
extending from Tai Hang to Pokfulam. It will
collect and divert surface runoff from the
upper catchment of Northern Hong Kong
Island via 34 planned intakes to the sea near
Cyberport.
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Interception Approach
Schematic Diagram
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Surface Runoff
on Street
Drainage System
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Surface
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Main Drainage Tunnel
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The ma i n drainage tunnel
is about 11 km in length and
6.25m to 7.25m in diameter. It
will be constructed at generally
100m below ground. The main excavation
works will be carried out mainly by using a
Tunnel Boring Machine and the majority of
the construction works will be carried out
underground.
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Intake
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34 intakes are planned along the tunnel
catchment area to intercept stormwate r
flow from major stream courses and/or
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underground pipes. The Intercepted flo w
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is then diverted through drop shafts to the
main tunnel. A total of about 8km associated
connection adits will be built.
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20071f-11F)30B
Project commenc ement d ate
30 November 2007
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Project completio n date
2012
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Project estimate
About HK$3,OOO million
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Controlling division
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A RU P Ove
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Arup & Partners Hong Kong Ltd
Consultant
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Contractor
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Drainage Services Department
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Project Management
Division
~ Dragages - Nishimatsu Joint Venture
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MAJOR BENEFITS
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Relieve the flo oding prob lem in the
Northern Hong Kong Island , in particular
the low-lying areas along Central, Sheung
Wan and Wan Chai
• Raise the overall flood protection level
• Reduce potential risk of damage to life,
property and economy during heavy
rainstorm
• Minimize disturbance to the public during
construction
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ENQUIRY
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DSD's Website
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Project Enquiry Hotline
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Drainage Hotline
www.dsd.gov.hk
2671 8600
23001110