ENG-1981 — Page 220

PUBLIC WORKS AND UTILITIES

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An intercepting sewer at Kowloon Bay Reclamation was completed, while construction of a screening plant at Central, a stormwater box culvert in Western Reclamation, and a sewage treatment works at Tai O started during the year.

Construction of sewage treatment works at Yuen Long, Tuen Mun, Sha Tin and Tai Po, sewage pumping stations at Hung Hom and Tsuen Wan, and a long submarine sewer outfall off the airport runway continued to progress satisfactorily. Detailed designs for the first stage of treatment works for northwest Kowloon continued.

Long-term monitoring of the quality of Hong Kong waters to establish pollution levels and trends and to provide data for the timely implementation of sewage treatment facilities continued throughout the year. A data report summarising all monitoring results up to mid-1980 was completed, and a technical report was prepared on the significance of the results, pollution trends and recommended action.

As regards solid waste management, about 1 408 000 tonnes of solid waste were treated and disposed of at the five controlled tipped sites at Sai Tso Wan, Ma Yau Tong, Siu Lang Shui, Shuen Wan and Junk Bay. During the year consultants were engaged to study the disposal of toxic, hazardous and difficult wastes in Hong Kong, to ensure that adequate arrangements are made and facilities available for dealing with such wastes. Consultants were also being considered for the development of a computer-based waste management planning system which will be used in the formulation and implementation of waste disposal plans.

Water Supplies

For the second year in succession rainfall was below average, with a consequent reduction in the quantity of water in storage. Additional resources were introduced by reactivating the Lok On Pai desalting plant and obtaining additional supplies from China. These measures were, however, inadequate to maintain a full supply and restrictions were imposed in October.

On October 1, 1981 - before the start of the restrictions - there were 255.96 million cubic metres of water in storage, compared with 380.67 million cubic metres on the same day in 1980. Rainfall for the year was 1 660 millimetres compared with the average of 2 225 millimetres.

In anticipation of a possible need to resume operation of the Lok On Pai desalting plant, preparations started early in the year to recommission progressively each of the six units of the plant from a 'care and maintenance' state. Reactivation was completed by the end of September and the plant was in full operation - producing some 182 000 cubic metres of fresh water a day - by early October.

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Also on October 1, 1981 the combined storage in Hong Kong's largest reservoirs, High Island and Plover Cove, was 197 million cubic metres. The salinity of the water at High Island remained at about 25 milligrams per litre while at Plover Cove the salinity varied from 86 milligrams per litre at the beginning of the year to 149 milligrams per litre at the end. A total of 211 million cubic metres of water was piped from China during the year, including an extra supply of 30 million cubic metres provided in response to a request to the Guangdong provincial authorities for additional water in the light of the low reservoir storage position.

Water restrictions helped maintain consumption at the 1980 level. A peak of 1.62 million cubic metres a day was reached, an increase of 1.3 per cent over the 1980 peak of 1.6 million cubic metres a day. The average daily consumption throughout the year was 1.39 million cubic metres, the same as in 1980. A total of 507 million cubic metres of potable