LAND, PUBLIC WORKS AND UTILITIES
the Countryside Series (six sheets) and the Tourist Guide, remains strong and the design and contents are continually under review to make subsequent editions more attractive to users.
Extensive cartographic and reprographic services are provided for other government departments. These include full-colour mapping for the geological series, base maps for weather forecasting, aeronautical charts, electoral boundary maps, pollution control plans and photo-reproduction and plan copying of all types by the Reprographic Unit. The unit also provides essential back-up for in-house map production and other cartographic activities.
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Installation of a computerised Land Information System at a capital cost of $24 million began at the Land Information Centre of the Survey and Mapping Office in late 1989. Conversion of large-scale mapping, land parcel boundaries, land use and zoning data will begin in early 1990. The new system will speed up the updating, processing and retrieval of land data and automate the production of basic survey sheets and cadastral plans. In view of its land information and data analysis capability, the land information system will be a powerful tool to assist decision-making in land administration and town planning. When the system is fully established, it will provide basic land information and a unique geographic reference system to both the public and private sectors in Hong Kong. As more users introduce their own compatible systems, an integrated network can be expected to grow. The system should be in operation for the first urban district in mid-1990 and the whole project completed by mid-1993.
The Photogrammetric Survey Section (with the Air Survey Unit operating from Royal Hong Kong Auxiliary Air Force aircraft) continues to provide aerial photographs and photogrammetric mapping for engineering design work, volumetric calculations for quarry and controlled tipping operations, environmental studies and specific development proj- ects. The Air Survey Unit is also on call for quick-response photography to assist in the investigation of flooding, air crashes and other emergency situations.
Water Supplies
Full supply was maintained throughout the year. At the beginning of 1989, there were 230 million cubic metres of water in storage, compared with 350 million cubic metres at the start of 1988. The combined storage of Hong Kong's largest reservoirs, High Island and Plover Cove, was 173 million cubic metres. Rainfall for the year was 1945 millimetres compared with the average of 2 225 millimetres. Water piped from China during the year totalled 610 million cubic metres. The salinity of water at High Island remained at about 21 milligrams per litre while at Plover Cove it varied from 71 milligrams per litre at the beginning of the year to 51 milligrams per litre at the end of the year.
A peak consumption of 2.63 million cubic metres per day was experienced, compared with the 1988 peak of 2.49 million cubic metres per day. The average daily consumption throughout the year was 2.32 million cubic metres, an increase of 5.0 per cent over the 1988 average of 2.21 million cubic metres. The consumption of potable water totalled 845 million cubic metres compared with 808 million cubic metres in 1988. In addition, 112 million cubic metres of salt water for flushing was supplied, compared with 110 million cubic metres in 1988.
The Lok On Pai Desalter was not operated and remained in a mothballed state. With reliable resources available from China and in view of the improved water storage situation it was decided to dispose of the desalting plant.
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