Hong Kong water comes from two sources – rainfall from natural mountain catchments, and by pipeline supply from Guangdong Province. Over the first hundred years of water supply in Hong Kong several inland dams were create as well as cisterns located at the top of hills. But with the increasing size of Hong Kong’s population and a shortage of natural storage reservoir sites led to the construction of Hong Kong’s first ‘reservoir in the sea’ at Plover Cove – the Plover Cove Reservoir.

And not before time. In 1963 and 1967, serious droughts affected Hong Kong. Our water supply was unable to support the needs of the rapid population growth of the 1950’s and early 60’s. In 1963 and 1967, there were periods when water supply was restricted to four hours per four days and people had to save water for four days’ use.

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.

Dongjiang is Hong Kong’s major source of water, and will meet all future increase in demand. It has so far supplied Hong Kong with more than 11 billion cubic meters of water, accounting for 80 percent of the fresh water supplied to Hong Kong.

In 1960, the agreement was reached with the Guangdong authorities whereby Hong Kong would purchase 23 million cubic metres of water each year. The supply from Guangdong stipulated under the latest agreement was increased to 810 million cubic metres a year in 2003.

This continued to increase by 10 million cubic metres per annum up to 2004, beyond which the annual supply quantity has been subject to further review. The designed maximum capacity of the supply system is 1.1 billion cubic metres per annum. The supply contract, costing HK$2 billion a year, has helped the city’s economy grow without the interruption of water shortage, although the payment constitutes only 0.15 per cent of Hong Kong’s HK$1.3 trillion gross domestic product.