食水：由水塘到東江

1. The reservoir era: starting from two million gallons

Pok Fu Lam Reservoir was completed in 1863 as Hong Kong’s first fresh-water reservoir, holding about two million gallons when commissioned; two expansions before 1877 raised capacity to 68 million gallons. The figure looks small today, but it marks a shift: water moved from wells, streams and springs to central storage and piped distribution, and the Government began managing the city through engineering rather than relying on natural sources alone.

The reservoir model has a built-in limit: capacity depends on catchment and rainfall. Hong Kong’s rain is concentrated in summer and dry seasons can be long; two poor years can empty the reservoirs. The rationing of 1963–64 was that limit at its most severe.

2. 1963–64: 360 days of rationing

Drought in 1963 and 1964 led to 360 days of rationing; at the tightest, water was available for only four hours every four days. The effect was not merely inconvenience: the official account records business depression, unemployment and rising prices, while the lack of clean water in summer worsened sanitation and increased cholera, dysentery and typhoid.

During the rationing the Government, with Guangdong’s consent, sent oil tankers to draw fresh water from the Pearl River. It was a temporary measure, but it pointed to the future: once local reservoirs could not carry the city, Hong Kong had to look beyond its boundary. The decision was simultaneously a water-engineering and a political question, not a purely technical arrangement.

3. East River supply: two figures, two scopes

In 1965 the East River–Shenzhen water supply project was completed and Hong Kong began importing raw water. That year one official passage says the project supplied 60 million cubic metres, one-third of total demand; another records actual imports of 49 million cubic metres. The two figures should not be added or treated as an error: one may be capacity and the other actual intake, but this site has not verified the definitions page by page, so they are set side by side.

By 2017 the recorded imports had risen to 651 million cubic metres. The increase reflects population and economic growth, and a falling share from local sources. When citing, ask whether the figure is capacity, actual intake or demand: the three are not interchangeable.

Keeping both figures may look indecisive, but for policy history it is safer to preserve two official formulations than to hide one behind an unverified definition. A reader who needs a single number should first find the definition in the original document, then say which one is being used.

4. Plover Cove and High Island: reservoirs built in the sea

Construction of Plover Cove Reservoir began on 20 February 1964; it was completed and began supplying water on 20 January 1969, and the record calls it the world’s first reservoir built by damming the sea. The design created storage beyond Hong Kong’s limited land, at the cost of managing seawater, salinity and catchment quality.

On 27 November 1978 the High Island Reservoir opened as Hong Kong’s largest, costing HK$1.35 billion and holding 273 million cubic metres; it entered supply on 9 February 1980. With Plover Cove, Hong Kong’s fresh-water reservoirs reached 17 and total storage 586 million cubic metres. The two reservoirs gave the city a buffer in dry years, but a buffer is not unlimited.

Reservoirs are stock; the East River is flow. Storage carries the dry season and emergencies, while flow meets everyday demand. If either is suddenly cut off, the other cannot carry the whole territory for long. That complementarity is the core of Hong Kong’s water system, and it explains why local reservoirs and imported water cannot simply replace each other. The claim that “with the East River we do not need reservoirs” ignores the role of reserve capacity.

5. How to read the sources

Reservoir and supply figures are mainly in the chronology p.150 (Pok Fu Lam), p.335 (start of Plover Cove), p.361 (Plover Cove supply and sea damming), p.417 (High Island opening and cost) and p.39 (completion of the East River scheme). For rationing and drought, see Nature: Natural Environment p.599; for Pearl River tankers, sanitation and actual imports, see Natural Resources and Ecology p.35 and p.48.

Keep two notes while reading: one for the year, one for the scope. The 1965 figures of 60 million and 49 million, and the 2017 figure of 651 million, sit at different levels; write down the scope before comparing. For policy research, go next to Water Supplies Department annual reports, Development Bureau water-supply papers and LegCo development panel documents.

6. Gaps

This dossier does not cover desalination, tariffs, leakage, reclaimed water or flushing water; East River prices, supply agreements and water-quality incidents are also absent. The definitions behind the two 1965 figures have not been verified page by page, so they are set side by side rather than reconciled. These gaps are not filled with “roughly” or “about”.

The next check is whether the Water Supplies Department annual report separates local catchment, East River imports and flushing water. If the three are mixed, any “self-sufficiency” claim will mislead. That is a question of scope, not engineering.