AECOM serves some of the world’s most complex infrastructure projects, such as the Harbor Area Treatment Scheme Stage 2A. The notion of this project, however, is loud and simple – “Our effort is made to achieve a cleaner harbor for the future of Hong Kong.” The Harbour Area Treatment Scheme (HATS) Stage 2A is one of the most important environmental programmes undertaken in Hong Kong with the objective of improving the water quality of Victoria Harbor.

The project works include construction of 21km of deep sewage tunnels covering the following areas:

  • from North Point to Wan Chai to Sai Ying Pun
  • from Ap Lei Chau to Aberdeen to Cyberport to Sandy Bay to Sai Ying Pun
  • from Sai Ying Pun to Stonecutters Island

The tunnels are at a maximum depth of 160m below sea level. Works also include associated production shafts, drop shafts, ancillary civil and E&M works. Control over groundwater ingress during tunnelling at such great depths and preventing building settlement are great challenges for this Project. Extensive ground investigation had been carried out by land boreholes, marine boreholes and horizontal directional coring at tunnel horizon to retrieve the ground samples and to obtain the hydrogeological information to aid the design.Most of the tunnels are constructed by drill-and-blast method, except a short section which is constructed by horizontal directional drilling. AECOM is responsible for the detailed design, tender documents preparation, tender assessment and construction supervision.