10
REVIEW
additional catchwaters were also built to augment the resources of the Tai Tam valley. The Jubilee reservoir itself was not finished until 1936, but it doubled the storage capacity for urban supplies. Thus, before the outbreak of the Second World War the Colony had thirteen reservoirs with a total storage capacity of 5,970 million gallons. Even so, restrictions had to be applied in 1937, and even before the outbreak of war there had been preliminary investigations into the possibility of damming the Tai Lam Chung valley to provide additional supplies. The war shelved this project and it was not re-opened until after the liberation of the Colony.
All this says little about the many and complex ancillary works associated with the storage and distribution of the urban supplies. The most remarkable of these is the system of catchwaters which follow the contours of the hills, intercept water from mountain streams and bring it to the reservoirs. Perhaps nowhere in the world have they been developed to quite such an extent as in Hong Kong. Where they pass over difficult and unstable ground they present major problems of design and construction. Probably the most serious difficulty is to determine their economic size. It would obviously be wasteful to design them to impound all the water available at times of torrential rainfall, and the aim is to collect the ordinary rainfall and to arrange for adequate overflows, preventing damage during periods of maximum flood.
Looking back over the pre-war history of water in Hong Kong, it is clear that there was a constant struggle to keep supply ahead of demand, that a lead was won for short periods only and that for most of the time the urban population was subject to water rationing. Two particularly bad years-1902 and 1929- stimulated a special effort to improve the situation and yet, by the outbreak of the war, the shadow of another crisis was already looming.
During the occupation of the Colony, the Japanese paid virtually no attention to the maintenance of the water installations, and their method of controlling consumption was simply to cut off large sections of the community and allow the mains to become derelict. Although little of the plant was removed or suffered direct war damage, a considerable backlog of repairs and rehabi- litation confronted the engineers on the liberation of Hong Kong.