Drops · Livability (Drainage Services Department)

Happy Valley and its neighbourhood are low-lying areas flanked by hills. In the past, heavy rains triggered frequent flooding, which had a significant impact on the public.

To protect people from the risk of floods, the Drainage Services Department (DSD) developed an innovative scheme to enhance flood protection in the district.

The project team installed a stormwater storage tank underneath the Happy Valley Recreation Ground. During heavy rains, the tank temporarily stores excessive stormwater. Conventional drainage improvement schemes in urban areas are normally upgraded in-situ and in a large scale. In comparison, building a storage tank and storing flood water below ground greatly reduces disruptions to traffic flows and the general public.

Movable weir

The stormwater storage tank features a movable weir, which is a mechanism deployed by DSD for the first time. The weir’s opening, closing and overall positioning are automatically adjusted according to the real-time information on tidal levels as well as the water levels in the drainage culvert upstream and downstream. This mechanism allows stormwater overflow into the storage tank at the optimal time.

Harvesting system collects groundwater and rainwater

The tank’s design also incorporates a sizeable water harvesting system that collects groundwater and rainwater. After undergoing some simple treatment, the water can be used for irrigating the Happy Valley Recreation Ground and for toilet flushing, thereby conserving water resources. These features ensure that the project is sustainable and in line with the concept of “Sponge City”.

Fan Room and Lawn

A stormwater storage scheme requires the construction of support facilities above ground such as a fan room and a pump house. The project team customised the design to make optimal use of the site in the interest of the public. With an environment-friendly design, the ground floor of the fan room is opened up as a public amenity. The pump house is covered by a lawn, providing a comfortable outside area for fun and game watching.

Going the extra mile, drop by drop, the project team consolidates stakeholders’ support and the fruit of joint efforts, bringing the project smoothly towards the goal of “Smart Drainage•Green Living”: flood protection and a more livable environment in tandem.

 

 

Partnering for innovation
CHENG Nga-see - Senior Engineer, Drainage Services Department

(For more details, please visit Sevice Excellence Website)