Happy Valley Stormwater Storage Tank Highly Effective

21 March 2018

Happy Valley, in between Morrison Hill and Leighton Hill, was one of the flooding blackspots in Hong Kong in the past. To correct that, the Drainage Services Department launched the “Happy Valley Underground Stormwater Storage Scheme” in 2012 and the contracted was awarded to Chun Wo Construction and Engineering Co., Ltd., a subsidiary of Asia Allied Infrastructure. The project entailed the building of a stormwater storage tank underneath the Happy Valley Recreation Ground to store rainwater collected from upstream catchments and help reduce flooding risk of low-lying areas in Happy Valley and Wanchai.

At the hard work of the project team, the “Happy Valley Underground Stormwater Storage Scheme” was completed near a year ahead of schedule. Phase one of the stormwater storage tank began operation in March 2015 and lived up to its purpose of flood relief during the rainy season that year. When the black rainstorm warning was issued on 24 May 2017, the highest hourly rainfall registered in Happy Valley and around Wanchai was 85.2 mm, and the stormwater storage tank collected 12 thousand cubic metres of rainwater, equivalent to what five standard size swimming pools hold. The stormwater storage tank had effectively freed Happy Valley, Wanchai and nearby areas from the threat of flooding and, at 6pm that evening, the Hong Kong Jockey Club held races on its Happy Valley course as scheduled, proving the effectiveness of the Stormwater Storage Scheme.

To minimise the impact of related construction works on stakeholders, Chun Wo actively discussed and collaborated with different parties on different measures. For instance, replacing pilings with raft foundation, which permitted much time and cost saving, plus prevented potential issues such as subsidence of the horse racing course and obstruction of view. Moreover, in the name of its "Harmonious Community Programme", Chun Wo organised from time to time different types of CSR activity to help it build closer relationship with the local community. To help people better understand the “Happy Valley Underground Stormwater Storage Scheme”, Chun Wo co-organised the “Happy Valley Green Carnival” with the Wan Chai District Council and Drainage Services Department, with game booths, exhibitions and models in relation to the project put up and souvenirs given out to joining residents. Such CSR events had encouraged communication and cooperation among stakeholders, resulting in smooth completion of the project.