Hong Kong West Drainage Tunnel

Completed Project

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
Construction period 2007 - 2012