Provision of potable water and flushing water in Hong Kong is a highly challenging task. Faced with a population over 7 million residing in a tiny area of about 1100 km2, we have had to develop ingenious solutions and extraordinary expertise in the management of water supply in Hong Kong. The primary challenges of WSD are not just the water delivery or treatment, but also the maintenance of a huge water infrastructure to ensure a sustainable and environmentally friendly water supply. Hong Kong’s water infrastructure comprises essentially catchwaters, tunnels, impounding reservoirs, water treatment works, pumping stations, service reservoirs and water mains. These infrastructure elements are the key components of two separate water supply systems, one for fresh water supply and the other for flushing water supply.
Hong Kong’s impounding reservoirs comprise two reservoirs constructed by damming the sea with other conventional reservoirs. Catchwaters and supporting installations such as tunnels and aqueducts have been constructed to transfer the rainwater collected to the reservoirs. Here the rainwater collected and any surplus raw water received daily from Dongjiang is held until it is required for the next stage in the supply process.
The treatment process of water treatment works is to purify the raw water to drinking water standards. In Hong Kong, the quality of treated water fully complies with the Hong Kong Drinking Water Standards (HKDWS).
Raw water, fresh water and sea water pumping stations of various sizes are dotted across Hong Kong. Each pumping station basically houses pumps and control equipment. Pumping stations can be manned or unmanned. They can be operated either in automatic mode or remotely from a regional control centre.
Fresh water and sea water service reservoirs are located in different sites across the territory. They provide transient storage for fresh water or sea water to cope with the peak demand and help manage the supply water pressure. They also serve as a buffer for maintaining supply when the trunk mains are not operating (e.g. during maintenance). Service reservoirs are normally constructed on high ground so that gravity will help assert enough pressure to supply water to customers through the distribution network.
Water mains are the pipes transporting water to the taps of our homes in every part of Hong Kong. They stretch above ground and underground; cross the harbour in submarine pipelines and feed urban and rural areas alike.
