ENG-1960 — Page 19

6

REVIEW

course many mountain streams and small rivers which during heavy rainfall become roaring torrents, but most of these dwindle to a trickle or dry up completely at other times of the year. There is an average annual rainfall of just under 85 inches, but three quarters of this falls during the summer months of May to September. Each summer it is vital to collect and store enough rainwater to last through the following winter.

Apart from climate and geography, the other important factor in the attempt to solve the equation of demand and supply has been the population. Once again Hong Kong's problem of people dominates the situation. In 1859, at the time of planning the first reservoir project, the population was about 90,000. On its com- pletion in 1863, it was already too small, for the number of inhabitants had grown to 125,000. This pattern was to repeat itself over and over again. By 1931 the population of the Colony had risen to 500,000 and in the following year the Japanese attack on China began. As the Japanese worked their way south, people crossed the border from Kwangtung province in increasing num- bers until, at the outbreak of the Pacific War, the Colony har- boured no less than 1,600,000. Then came the outbreak of the Pacific War and the occupation of the Colony by the Japanese. During this period wholesale expulsions reduced the population to 600,000, but from the liberation of the Colony onwards the upward trend continued and quickly intensified. By the end of 1946, the pre-war figure of 1,600,000 had been overtaken; by 1956 it had gone up to 2,500,000; today, just 101 years after the first reservoir was planned, the population is thought to be in the region of 3,200,000. The census in March 1961 will tell how accurate this estimate is and will make planning for the future somewhat easier than in the last fifteen years.

The loss of Government records during the last war has obscured the history of Hong Kong's waterworks. Fortunately some of the past has been pieced together from such records as still exist, and from the memories of those who, in the early years after the war, were still here to recall the details. Some of this history is recorded in a paper read by Mr Leonard Jackson, lately of the Public Works Department, before the Engineering Society of Hong Kong in December 1948. The present review owes a great deal to this source for its information on the pre-war years.