HK$1.2 billion drainage plan to collect reservoir excess will save city 3 million cubic metres of water – enough for 70,000 Hongkongers yearly
But expert questions if HK$19.7 million saved from importing this amount from mainland is worth it, against city’s massive consumption bill
Hong Kong will save more than 3 million cubic metres of water each year when a project to collect excess run-off from four Kowloon reservoirs is completed, drainage officials have said.
According to the Drainage Services Department, the amount could meet the annual demand of 70,000 Hongkongers.
At present, all excess rainwater goes to waste once the reservoirs are full, because it flows downhill into storm drains and out to sea.
The plan centres on transferring water between reservoirs when they fill up during periods of heavy rain.
A 2.8km tunnel will connect Kowloon Byewash Reservoir – which is fed by the Kowloon, Shek Lei Pui and Kowloon Reception catchments – to Lower Shing Mun Reservoir through Kam Shan Country Park.
Works could begin as early as next year, and the design would involve automated water gates releasing excess water into the tunnel once the reservoirs reach capacity.
“The four reservoirs only have a capacity of about 2.8 million cubic metres,” drainage chief Edwin Tong Ka-hung said. “The storage capacity is not really sufficient and they have a tendency to overflow.”