The structure will alleviate flooding in the Lai Chi Kok, Cheung Sha Wan and Sham Shui Po areas.
The HK$1.7bn (£140m) project involves the construction of a branch tunnel and a main tunnel with a total length of 3.7km. Storm water will be channelled to the branch tunnel through six intakes and via 270m of adits. Together with storm water from Butterfly Valley, the combined flow will be conveyed by the main tunnel into Victoria Harbour near Stonecutters Island.
“Upon completion of the project, the flood protection level in Lai Chi Kok, Cheung Sha Wan and Sham Shui Po will be able to withstand rainstorms with a return period of one in 50 years,” said director of drainage services Chan Chi-chiu. “This will greatly alleviate the risk of flooding and associated impacts on the public, traffic and commercial activities.”
Construction started in November 2008 and the branch tunnel breakthrough took place in January this year. Work is scheduled for completion by late next year.