ENG-1980 — Page 214

PUBLIC WORKS AND UTILITIES

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acceptable in the waters where it is discharged. Sewage from rural areas where sewage systems are not provided is sometimes disposed of through separate sewage treatment facili- ties such as septic tanks, Imhoff tanks and package sewage treatment plants.

A major stormwater culvert and intercepting sewer was completed during 1980 at Aldrich Bay Reclamation in Shau Kei Wan.

Construction of sewage treatment works at Yuen Long, Tuen Mun and Sha Tin and sewage pumping stations at Hung Hom and Tsuen Wan continued to progress, while work on detailed designs for additional sewage treatment facilities at Sha Tin and Tai Po, and for the first stage of treatment works for northwest Kowloon, also went ahead satis- factorily. The design for the sewage treatment works at Tai O an Lantau was completed. Work started on the construction of a trunk sewer in Kowloon Bay reclamation and a long, submarine sewer outfall off the airport runway at Kai Tak.

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-1979 was completed, and a technical report was prepared on the significance of the results, pollution trends and recommended action.

About 1,130,000 tonnes of solid waste was treated at the five controlled tipping sites at Sai Tso Wan, Ma Yau Tong, Siu Lang Shui, Shuen Wan and Junk Bay. The controlled tip at Gin Drinkers Bay was completed.

A refuse composting plant at Chai Wan became operational during 1980, and com- missioning trials of the refuse baling plant, at Sai Tso Wan, were completed.

Port Works

On Hong Kong Island, construction work was completed on 570 metres of seawall forming a breakwater arm for cargo-handling purposes in Western District. The construction of 900 metres of seawall foundation in Western District was also completed and a new contract was let for the seawall superstructure. New contracts were let for the construction of a 90 metre-long breakwater at Kellett Island and 510 metres of seawall in Aberdeen. Work on the construction of 675 metres of seawall continued at Quarry Bay, and construction of 185 metres of seawall with pump-houses was in progress at Tamar East Basin.

In Kowloon, construction of salt water pump-houses at Tsim Sha Tsui was completed and a contract was let for the construction of 400 metres of seawall in Cheung Sha Wan. In the New Territories, work was well advanced on the construction of a seawall and related reclamation works in the Rambler Channel Typhoon Shelter to extend the existing cargo-handling area. At Cheung Chau, construction work on the foundations for a breakwater was completed, and work commenced on forming the breakwater superstructure.

Water Supplies

Despite below average rainfall in 1980, a continuous water supply was maintained through- out the year. At the beginning of 1980 there were 403 million cubic metres of water in storage, compared with 361 million cubic metres at the start of 1979. Rainfall for the year was 1,710.6 millimetres compared with the average of 2,246.4 millimetres.

On January 1, 1980, the combined storage in Hong Kong's largest reservoirs, High Island and Plover Cove, was 363 million cubic metres. The salinity of the water at High Island remained at about 26 milligrams per litre while at Plover Cove the salinity varied from 74 milligrams per litre at the beginning of the year to 86 milligrams per litre at the end.