232
HONG KONG ANNUAL REPORT
the Tai Lam Chung tunnel for repairs in March, described later, made it necessary to reduce the period of supply to three hours daily. Upon completion of the repairs at the beginning of April, the eight-hour period was restored; and on 24th April was increased to ten daily. June turned out to be the wettest on record, and a twenty-four-hour supply was given on 16th June when a new record consumption of 93.34 million gallons per day was established; the previous highest being 83.9 million gallons on 4th September 1958. This unprecedented demand resulted in some service reservoirs being emptied faster than it was possible to re- fill them, and it was found necessary to restrict the supply during the night to enable the service__reservoirs to refill. A very wet summer, when every reservoir overflowed for lengthy periods, enabled a seventeen-and-a-half-hour supply period to be main- tained in most areas from 17th June to 2nd October when the hours were reduced to thirteen daily. In anticipation of a dry October, the hours were again reduced to eight on 11th October; but the complete absence of rainfall during the month made a further cut to four hours a day necessary on 30th October.
The average daily consumption was 59.89 million gallons as against 53.03 last year, an increase of 12.9 per cent. The maximum consumption was 11.3 per cent higher than last year's highest figure.
A section of the delivery tunnel on the Tai Lam Chung Scheme, which had given trouble previously, developed further leakage at the beginning of 1959. Attempts were made to repair the leakage without interfering with supply by drilling and grouting from outside the tunnel, but this was not effective. The tunnel was therefore emptied on 12th March, and supplies were restricted to three hours a day. There followed an intensive period of activity in which internal radial holes were drilled and grouted over the first 400 feet length of the suspect tunnel, and finally a 36-inch diameter steel pipe was laid inside the tunnel to preclude the possibility of further leakage due to cracking of the tunnel lining. This work was completed on 2nd April and the supply hours were increased to eight hours a day on 4th April.
The year's work included a large programme of main laying to enlarge existing services and extend the distribution system. An important factor contributing to the rapid increase in the demand