Tai Hang Tung Storage Scheme

The Tai Hang Tung Storage Scheme was designed to prevent flooding in Mongkok area caused by heavy rainfall sweeping southward from Lion Rock.

The problem was highlighted by the severe flooding in the area in 1997 and 1998. Years of development in Kowloon Tong and Yau Yat Tsuen areas had increased the amount of surface runoff downstream. Although there were three main stormwater drains serving the area, they were no longer adequate for the task.





The Tai Hang Tung site proved to be the perfect choice because it was located just above the bottleneck and was thus best situated to intercept the heavy flow. In the scheme, a 136 m long, 130 m wide and 7.5 m internal depth storage tank under the rugby pitch and football pitch was constructed with a target flow interception of 70 cubic metres per second into the tank during heavy rainstorms. To add flexibility to the system, a steel mechanism was fitted to the top of the weir to permit height adjustments from 5.4 m to 5.7 m.

The storage tank, which has a 100,000 cubic metres capacity, is the first large-scale underground flood storage tank in Hong Kong. It was designed to handle rainstorms with a return period of 50-year which could dump more than 100 mm/hour, much more than the 70 mm/hour rainfall categorized as “black rainstorm” by the Hong Kong Observatory. The performance of the storage tank has been tested for robustness under eight historic or synthetic rainstorm scenarios based on local and overseas design standards.

The project was completed in September 2004 and won the HKIE’s Innovation Award in 2002 and Merit Award in Skyrise Greenery Award in 2012."  

The flood water pumping station at Tai Hang Tung Storage Scheme

Main Components of Stormwater Storage Scheme

Trunk Drains in Mong Kok Area
Dry Wet Well 3 numbers of centrifugal pumps (Two Duty and One Standby) Each of 0.95 m3/s for dewatering the storage tank 100,000 m3 in 15 hours
Underground Storage Tank, capacity of 100,000 m3
Pumping station roof