During heavy rainstorms, huge flows coming from Northwest Kowloon mid-level will discharge to habour via the costal urban areas. Much of the stormwater drainage system in the Lai Chi Kok, Cheung Sha Wan and Sham Shui Po area was built serveral decades ago. With continuous urbanization and development, the capacity of the existing drainage system is no longer adequate to cope with the increasing flows during times of heavy rainstorms and floodings will find at the costal urban areas.
Lai Chi Kok Drainage Tunnel adopted an interception approach which six intakes are constructed along Northern side of Ching Cheung Road to intercept stormwater flow. The intercepted flow is then diverted to the stilling basin via the branch tunnel and then further discharge to the harbor via the main tunnel. The drainage tunnel provides a flood relieve measures for the low-lying urban areas at Lai Chi Kok, Sham Shui Po, and Cheung Sha Wan areas.
The traditional approach requires enlarging the existing drainage system within urban area while the tunnel interception approach is an innovative flood relief measure. The construction work sites are located in rural areas such that extensive road openings can be avoided and minimize the disturbances to the public, traffic, and commercial activities and at the same time achieving the flood relief purpose.