Advisory Council on the Environment

Strategic Sewage Disposal Scheme - Stage I Information Note on the Progress of the Tunnelling Works (as at end March 1999)

(ACE Paper 15/99)
for information by circulation only

The six sewage tunnels for the collection and transfer of sewage from the urban Kowloon and north east Hong Kong Island to the Stonecutters Island Sewage Treatment Works for treatment were originally scheduled for completion in mid 1997. Owing to the unilateral suspension of tunnelling works by the original contractor in mid-1996, the Government decided to re-enter the tunnel contracts in December 1996. The tunnel completion works were relet in three separate contracts with two tunnels each. The contract for completing the western tunnels (i.e. the two tunnels running from Kwai Chung and Tsing Yi to Stonecutters Island), i.e. Contract No. DC/96/20, was awarded in July 1997. The other two contracts for completing the eastern tunnels (i.e. the four tunnels running from Tseung Kwan O and Chai Wan to Stonecutters Island), Contract Nos. DC/96/17 and DC/96/18, were awarded in January 1998. The progress of the tunnelling works up to end March 1999 is :-


Tunnel Length of
completed up to
last quarter
completed in
this quarter
up to date
Western Tunnels
Tunnel from Kwai Chung to Tsing Yi 779 740 (95%) 39 (5%) 779 (100%)
Tunnel from Tsing Yi to Stonecutters Island 3580 897 (25%) 358 (10%) 1255 (35%)
Eastern Tunnels
Tunnel from Tseung Kwan O to Kwun Tong 5332 629 (12%) 1013 (19%) 1642 (31%)
Tunnel from Chai Wan to Kwun Tong 4830 799 (17%) 104 (2%) 903 (19%)
Tunnel from Kwun Tong to To Kwa Wan 3572 647 (18%) 647 (18%) 1294 (36%)
Tunnel from To Kwa Wan to Stonecutters Island 5495 440 (8%) 565 (10%) 1005 (18%)

In total, 6.9km (29%) of the 23.6km tunnel system has been excavated up to end March 1999. The excavation for the tunnel from Kwai Chung to Tsing Yi was completed on 21 January 1999. Despite the difficulties encountered during the early stage of tunnelling works which caused a delay of about eight months to the overall completion of the system, progress of the tunnelling works is picking up steadily. It should be noted that the risk of encountering difficult ground condition still remains as the work proceeds. We shall continue to work hard to achieve our target to complete the Strategic Sewage Disposal Scheme - Stage I project as a whole by end year 2000.

Drainage Services Department
April 1999


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