Happy Valley, located in the Wan Chai District of Hong Kong, is a cultural, economic and entertainment centre for the city. Despite its metropolitan development, the area was prone to flooding as it is located on low-lying ground near the Victoria Harbor. The Happy Valley Racecourse, one of Hong Kong’s most popular attractions, was submerged under nearly three feet of stormwater during a severe rainfall event in 2008.
The traditional solution to resolve this type of flooding would be “throwing more drains at the problem areas" said Black & Veatch* Project Director Andy Kwok. However, enlarging and multiplying the number of drains would involve opening up busy roads in Wanchai and around the racetrack and disrupting popular racing and sporting events. Furthermore, even with all these disruptions, this strategy wouldn't effectively reduce flooding risk because part of the low-lying drains adjacent to the sea would still be occupied by tidal water, thus reducing the flood protection efficiency.
In view of the effectiveness and public interest, the Drainage Services Department (DSD) of the Government of the Hong Kong Special Administrative Region decided to implement an underground storage scheme, comprising a large tank to store stormwater runoff for reduction of downstream flooding risk during severe rainfall events.