It’s horse-racing day, but heavy rain with the risk of flooding is predicted for low-lying areas like Happy Valley. Should the races be called off? That decision is much easier to make today thanks to the Happy Valley Underground Stormwater Storage Scheme (HVUSSS), which has helped to reduce the likelihood of flooding. 

People attending the races at Happy Valley or using the sports facilities may well be unaware of the engineering marvel beneath their feet. Thirty members took the opportunity to explore this underground system during a Chamber visit on 19 April. 

The HVUSSS, comprising a 60,000-cubic-meter stormwater storage tank, is Hong Kong’s first application of a movable weir system, which is integrated with a real-time monitoring system and uses augmented reality technologies. This means that it can adapt to collect stormwater at times when heavy rainfall may otherwise overwhelm the existing drainage system. 

The scheme also fosters the development of a sustainable water supply. “The groundwater collected is reused as irrigation water for the sport pitches and flushing water in toilets at the Happy Valley Recreation Ground,” said Tong Kwan Shing, Engineer, Drainage Projects Division, Drainage Services Department. 

The HVUSSS has been cleverly integrated with the existing landscape so it is largely invisible at ground level. “A turfed slope has been built on top of the Pump House, which not only provides a serene public space and open-air vantage point but also helps to reduce the indoor temperature,” Tong explained. 

Members got a first-hand look at the movable weirs in action during the visit, as the gates regulated the flow of water.   

Black & Veatch Hong Kong, the engineering firm that designed the HVUSSS, won the Innovation and Creativity Grand Award at the 2017 Hong Kong Awards for Industries in recognition of its innovative work on the project.