Work started on Hong Kong's West Drainage Tunnel (HKWDT) scheme in November 2007 in a 49 months contract to alleviate the flooding problems in northern Hong Kong island.  The contract for the project was awarded by the Drainage Services Department to the Dragages-Nishimatsu Joint Venture.
     The scope for the new HKWDT project involves construction of a new 11 km long drainage tunnel deep in the ground in the mid-levels of the island from Tai Hong to Pokfulam. The scheme will intercept and convey the storm water from the upper catchment directly into the sea near Cyberport.
     The tunnel is being constructed in two sections.  The first, 4.5 km long and 6.25 m in diameter, runs the Tai Hong to beneath the Aberdeen Tunnel. The second, 6 km long and 7.25 m diameter, is from the Aberdeen Tunnel to Cyberport.
     The main tunnels will be constructed by two tunnel boring machines starting from the Eastern Portal at Tai Hong and the Western Portal at Cyberport. Along the main tunnel there will be 35 intake shafts up to 180 m depth. The shafts are connected by 29 adits totalling 8 km. The tunnels will be lined by the concrete ring segments.
     A Liebherr 550 EC-H 20 tower crane is providing a key support role on the unloading pre-fabricated concrete ring segments, each weighing between 1.92 to 6.55 t. With a 20 t lifting capacity the crane is currently considered to be Hong Kong's biggest crane.
    Weekly delivery to the project at Cyberport by barge conveys a total of 312 segments comprising six segments per ring. As the scheme progresses, barge deliveries will be increased to two, and at a peak, three. The pre-formed concrete segments are lifted from the barge into the storage yard, for delivery by the site's overhead gantry crane into the projects Western Portal.