LAND, PUBLIC WORKS AND UTILITIES
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The computerised land information system is being installed in District Survey Offices by phases once the digital map data and land records are available. The system processes and analyses land information and is a useful tool for enquiry on land status and decision making. The system also automates the production of large scale maps and cadastral plans. Up-to-date mapping and boundary information can be made readily available to users. Besides producing standard 1:1 000 survey sheets containing full topographical features, the system can also produce plans according to the user's specifications. The users can choose the features to be shown, such as buildings, roads and contour lines; colours and symbols for different features; and plan scale and plan size. Mapping information in digital form may be supplied to the public on payment of a licence fee and direct on-line access to the central mapping data may also be possible. The data conversion for other districts in the territories will be speeded up by contracting out the work and is scheduled to be completed by 1994.
The Photogrammetric Survey Section provides aerial photographs and photogrammetric mapping as well as data for engineering design work, volumetric calculations for quarry and controlled tipping operations, environmental studies and town planning work. The Air Survey Unit is also on call for quick response photography in emergency operations such as storms, flooding and landslips.
Drainage Services
The Drainage Services Department is responsible for planning, designing, constructing, operating and maintaining sewerage, sewage treatment and stormwater drainage infra- structures.
Treatment and disposal of foul water
The treatment and disposal of foul water, that is domestic sewage and trade and industrial effluent, is based on standards, strategies and programmes drawn up by the Environmental Protection Department. Projects on foul water disposal can be broadly divided into three categories: 'existing schemes' which are sewerage or sewage treatment projects which have been in the public works programme before the new strategy evolved and which are compatible with the new strategy for the treatment and disposal of sewage to satisfy new water quality standards; 'sewerage masterplan schemes' which are sewerage rehabilitation and improvement projects to ensure the proper collection of sewage in foul sewers, and the 'strategic sewage disposal scheme' which is a massive project to collect all the sewage from Hong Kong Island, Kowloon, Tsuen Wan and Tseung Kwan O into a deep tunnel intercepting sewer system that will discharge, after treatment on Stonecutters Island, through a long sea outfall into the Dangan Channel.
Under the 'existing schemes' category the largest project is the North West Kowloon Sewage Treatment and Disposal Scheme. In this scheme, the sewage from Sham Shui Po, Mong Kok and Yau Ma Tei with a total population of about 1.2 million will be collected and treated prior to discharge. All construction works have been completed and the operation of the scheme has been in commission since August 1992. The second largest project in this category is the Tolo Harbour Effluent Export 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, submarine pipelines