PUBLIC WORKS AND UTILITIES
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A considerable proportion of the sand needed by Hong Kong was met by dredging suitable deposits in Mirs Bay, and a total of 960,082 cubic metres of marine sand was sold through government sand depots. In addition, 129,232 cubic metres of sand manufactured from crushed rock and supplied through government contracts was sold at the sand depots. The construction of a sand depot at Kowloon Bay was completed early in the year. Work started on the new sand depot at Lai Chi Kok which will be used for maintaining the marine sand service. A start was made on the design of additional sand depots to serve the New Territories, and construction of these depots is expected to follow shortly.
Water Supplies
Below average rainfall fell during January and February but early summer rains in March and April enabled water restrictions, which had been in effect since June 1, 1977, to be lifted. A full supply was restored from April 19,1978, to the end of the year.
Storage at the beginning of 1978 was only 187 million cubic metres, compared with 238 million cubic metres at the start of the previous year. But by October the situation had improved considerably, with 347 million cubic metres (or 60.1 per cent of the total capacity, which now includes High Island Reservoir) held in storage, compared with 202 million cubic metres at the same time in 1977. Rainfall for the year was 2,593 millimetres compared with an average of 2,246 millimetres.
On January 1, the combined storage in Hong Kong's two largest reservoirs, High Island and Plover Cove, was 148 million cubic metres. The quality of water impounded in these reservoirs was satisfactory throughout the year: salinity contents at the end of the year being 35 and 79 milligrammes per litre respectively.
A total of 144 million cubic metres of water was piped from China during the year. An additional nine million cubic metres is to be supplied from October, 1978, to July, 1979, following a further agreement reached with the Bureau of Water Conservancy and Electric Power, Kwangtung Province.
Due mainly to the lifting of water restrictions, fresh water demand increased over the previous year with the average consumption being 1.13 million cubic metres a day, compared with 1.06 million cubic metres'a day in 1977. In addition, 76 million cubic metres of salt water were supplied for flushing purposes.
At High Island Reservoir, which has a capacity of 273 million cubic metres, con- struction of the east dam was completed by June, thus bringing the reservoir basin to its full height. All other works were substantially completed and the project was officially opened by the Governor on November 27.
The 182,000 cubic metres a day desalting plant at Lok On Pai continued to operate at full output until May when, with a favourable reservoir storage position, a phased shutdown commenced. Plant operation ceased early in June. Planned maintenance commenced and detailed feasibility studies into ‘mothballing' the plant were in hand. Shift working on the plant was reduced to a caretaker basis, with the balance of operational staff redeployed to supplement maintenance staff at Lok On Pai and to assist other divisions of the Water Supplies Department. General investigations con- tinued into the various alternative desalting processes and the assessment of possible future plant sites.