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Providing an adequate water supply for Hong Kong has
always been difficult because there are no natural lakes,
rivers or substantial underground water sources. The annual
rainfall averages 2 398.5 millimetres but this is insufficient to
meet current demands — the average daily consumption of
potable water during 2015/16 being 2.68 million cubic
metres.
The Water Supplies Department is a government department
providing potable water to the people living within the Hong
Kong Special Administrative Region. The department also
supplies sea water for flushing.
Sources of Water: Hong Kong’s two main sources of water
are rainfall from natural catchments and Dongjiang water
from Guangdong Province. Shortage of natural storage
reservoir sites led to the construction of Hong Kong’s first
‘reservoir in the sea’ at Plover Cove. The initial scheme,
completed in 1967, was created by damming, and draining
an inlet of Tolo Harbour and had a storage of 170 million
cubic metres. The storage was increased in 1973 to 230
million cubic metres by raising the dam. A similar but larger
scheme at High Island, completed in 1978, has a capacity of
281 million cubic metres. The total storage capacity of Hong
Kong’s reservoirs is 586 million cubic metres.
Supply from Guangdong: Dongjiang is Hong Kong’s major
source of water. Dongjiang water first started to be supplied
to Hong Kong in 1965. Today, about 70-80 per cent of water
comes from Dongjiang by arrangement with the Guangdong
authorities. 747 million cubic metres of Dongjiang water was
imported in 2015/16. The Dongshen-Hong Kong water
supply system is designed to be capable of providing Hong
Kong with 1.1 billion cubic metres per annum.
Sea Water for Flushing: An interesting facet of the
waterworks is the sea water supply systems with their
separate networks of distribution mains, pumping stations
and service reservoirs. In 2015/16, an average of about
730 000 cubic metres of sea water was supplied each
day.
Consumption (in million cubic metres):
Fresh Water 2014/15 2015/16
Annual 961.46 982.15
Daily Average 2.63 2.68
Highest Daily 2.85 2.93
Sea Water
Annual 273.17 267.89
Daily Average 0.75 0.73
Rainfall and Yield: About one-third of Hong Kong’s 1 098
square kilometres has been developed as water catchments.
Water Treatment: The supply is fully treated by chemical
coagulation, sedimentation (at most treatment works),
filtration, disinfection by chlorination, pH value adjustment,
chlorination and fluoridation. The drinking water is soft in
character and conforms fully to the Guidelines for Drinkingwater Quality recommended by the World Health
Organization.