LAND, PUBLIC WORKS AND UTILITIES
and Yau Ma Tei. All the construction contracts have been awarded and one has been completed. The second largest project in this category is the scheme to ‘export' the sewage effluent from the Sha Tin and Tai Po sewage treatment works and discharge it into Victoria Harbour. The works comprise sewage pumping stations, rising mains and a sewer tunnel of 3.2-metre diameter and 7.5 kilometres in length under Tsz Wan Shan. This is the first government project in which a tunnel-boring machine was used. Construction will be completed by 1993. The biggest-ever sewage screening plant in Hong Kong which will serve a population of 1.2 million in the Tsuen Wan and Kwai Chung area will start construction at the end of the year for completion in April 1994. Construction of the Ha Tsuen sewage pumping station, the San Wai sewage treatment works, and the rising main between them, which together form part of the North West New Territories Sewerage Scheme, will be completed in 1992. The extension of Yuen Long sewage treatment works will also be completed in 1992.
Under the sewerage masterplan scheme, five contracts have been awarded to improve the sewage disposal facilities in the Southern District of Hong Kong Island. In East Kowloon, design for sewerage improvement is nearing completion and construction will commence early in 1992.
Under the strategic sewage disposal scheme, detailed engineering feasibility studies have been progressing well and will be completed in 1992.
With the commissioning of each additional item of infrastructure there is a consequential increased commitment in operations and maintenance. By the end of the year, territory- wide, some 1.15 million cubic metres per day of sewage were receiving grit removal and screening and another 300 000 cubic metres were receiving full biological treatment, and the 1 400 cubic metres-capacity purpose-designed vessel Sha Tin Prince commenced opera- tion in March 1991 for dumping at sea the sludges from both sewage treatment works and water treatment works at Sha Tin, Plans were made to carefully monitor the environmental effect of such dumping.
Since the establishment of this department, the approach to operation and maintenance of the public drainage system has progressively shifted from crisis management to preventive maintenance; resources are being deployed to carry out regular inspection, cleansing, repair and minor improvement of the system, especially at identified drainage black spots. The results are promising and although the public drainage system is becoming larger and more complex with urbanisation, the number of drainage complaints, chokage and flooding show steadily declining trends. The department now maintains 2800 kilometres of watercourses, drains and sewers, increasing at the rate of 40 kilometres per year. Some 80 000 cubic metres of silt are removed from drains and watercourses each year to keep their pollution level low and keep them free-flowing.
Further to the initial territory-wide study carried out by consultants in 1989 to review rainfall, stream flow and flooding predictions, the government has commissioned a second study on flood control which is concentrating on North and North-west New Territories. This study aims to draw up basin management plans for the river basins in the North and North-west New Territories and examine in more detail what local flood mitigation measures can be taken. In addition, pamphlets giving advice on what to do and what not to do in a flooding situation are widely distributed through the District Offices to people living in flood-prone areas. An Emergency and Storm Damage Organisation has been set up to deal with emergency flooding cases.
URBAN COUNCIL PUBLIC LIBRARIES REFERENCE LIBRARY
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