Challenges in implementation of a Flood Relief Underground Storage Scheme in Happy Valley, Hong Kong

Cheuk Lun Leung, Jimmy SS Poon, Karen K Y Chan, Irene Y Y Chan

Friday 3 july 2015

12:42 - 12:45h at Oceania Foyer (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Flooding along in rivers and coasts, Poster pitches

Parallel session: Poster pitches: 15L. Flood Risk - Flooding

The Happy Valley Underground Stormwater Storage Scheme (HVUSSS) is proposed at the middle reach of the drainage system and is located at the city centre of Hong Kong. It comprises mainly a 60,000 cum underground storage tank to attenuate the peak discharge on the drainage system so as to alleviate the persistent flooding problem of the low-lying areas at Happy Valley and nearby districts. During the course of construction, the inherent geographical constraints of the site such as in the proximity of the aged buildings and high voltage cables, presence of heterogeneous marine deposits and irregularities in the aged drainage networks, and the increased public expectation for timely commissioning of the HVUSSS had all posed challenges and difficulties to the participants of the project. This paper presents the difficulties and challenges faced by various parties during the construction of the underground storage tank and associated box culvert and stilling basin, and the solutions adopted to overcome these difficulties through design revision with mathematical and physical modeling verification, proper sharing of risk amongst parties and meeting public interests at large.