Visits and Tours

Technical Visits

Lai Chi Kok Drainage Tunnel cum Tai Hang Tung Stormwater Storage Scheme

Many of the stormwater drainage systems in Kowloon, namely Lai Chi Kok, Cheung Sha Wan, Sham Shui Po and Mong Kok, were built several decades ago.  With continuous urbanization and development, the capacity of these systems are inadequate to meet the prevailing flood protection standard.  During heavy rainstorms, fast and huge runoff from the hills would run along the paved areas and steep slopes down to the downstream urban areas, causing flooding hazards. 

Lai Chi Kok Drainage Tunnel (LCKDT) and Tai Hang Tung Stormwater Storage Scheme (THTSSS) are part of the long term measures for resolving the flooding problem in urban areas of Hong Kong.  The functions of LCKDT are to intercept and divert storm flows from upland catchment for direct discharge into the sea, while the THTSSS temporarily stores stormwater in an underground tank for subsequent discharge back to the existing downstream drainage system when rainstorms subside. 

By employing these measures, less rainwater would enter the existing drainage systems in the urban areas or part of the rainwater would be detained.  Therefore, the flood protection standard of the areas could be uplifted without the carrying out of traditional drainage improvement works.

Highlights

Lai Chi Kok Drainage Tunnel

• LCKDT is located at West Kowloon mid-level to collect runoff from natural terrain and thus reduces the volume of peak flow at the existing drainage systems.  It serves to alleviate flooding risk at Lai Chi Kok, Cheung Sha Wan and Sham Shui Po areas.
• The project commenced in November 2008 and LCKDT was commissioned in October 2012.
• Project cost: about HK$ 1,700M
• The project mainly comprises 3.7 km of tunnel of 4.9m internal diameter, 6 intakes, a stilling basin, 2 shafts and an outfall.
• Design flow of tunnel: 102 m³/s

Layout of LCKDT


Illustration of Drainage Tunnel Scheme

Tai Hung Tung Stormwater Storage Scheme

• The THTSSS, an integral part of the West Kowloon drainage improvement scheme, was designed to address the flooding risk in Mong Kok area.  The stormwater storage tank was constructed underneath Tai Hung Tung Recreation Ground, which serves to reduce rainfall volume discharging into existing unban drainage systems. Stormwater will spill over the overflow weirs into the storage tank during heavy rainstorms.
• The Project was completed in November 2004.
• Project cost: about HK$290M
• The project mainly comprises an underground storage tank of capacity 100,000 m³, a pumping station with pumping capacity of 0.95 m³/s for dewatering of storage tank, and connections to existing upstream and downstream drainage systems.

Illustration of the THTSSS

Interior of THT Underground Storage Tank