• Main tunnel from Tai Hang in the east to Pokfulam in the west

  • 11-km long main tunnel

  • The largest hard rock double-shield TBMs in Hong Kong

  • One of the TBMs used in Hong Kong’s largest flood-prevention project

  • Main Tunnel broke through in January 2011

  • Installation of precast ring down to 170m shaft

  • FIRST in Hong Kong: Extensive adoption of Raise Boring Machines

  • Commissioning ceremony held in August 2012

  • International Tunnelling Awards 2011 – Tunnelling Project of the Year (US$100 million to US$1 billion category)


Hong Kong West Drainage Tunnel


Designed to alleviate Hong Kong’s seasonal flooding problems, the massive Hong Kong West Drainage Tunnel stretches deep underground across the western spine of Hong Kong Island. The tunnel collects excess surface runoff from the Mid-Levels area and above, and then discharges it directly into the sea, thus bypassing the highly urbanised areas downstream.


Offering an innovative solution to the seasonal flooding problems, the project has achieved a number of technical “firsts” in Hong Kong’s construction industry: adoption of the largest hard-rock Tunnel Boring Machines (TBMs) (7.2m and 8.3m diameters respectively); the first to employ TBM excavation and blasting concurrently; and the first to extensively adopt Raise Boring Machines. All these measures ensured that disruptions to the community were kept to the minimum, including the minimisation of road traffic, noise and dust.


The project was named “Tunnelling Project of the Year” (US$100 million to US$1 billion category) at the International Tunnelling Awards 2011, with judges remarking, “This is a model tunnelling project, delivered under difficult circumstances.”



Client Drainage Services Department, Hong Kong Government
Project Design and Construction of Hong Kong West Drainage Tunnel
Eastern tunnel 6.25-m diameter
Intakes 34
Western tunnel 7.25-m diameter
Year 2007 - 2012