ENG-1995 — Page 261

LAND, PUBLIC WORKS AND UTILITIES

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maps, except the 1:1 000 basic map series, are bilingual. Guide book, tourist guide and leisure maps in the form of the Countryside Series produced by the Office are very popular.

The Survey and Mapping Office provides extensive Cartographic services for many government departments. These include the production of coloured geological maps, thematic maps, weather forecasting plans, aeronautical charts, electoral boundary maps and pollution control maps. Plans are also prepared for legal purposes, land disposals, street and place naming, government gazette notices, setting out of private land parcels, and for land boundary identification.

The computerised Land Information Systems being implemented in the District Survey Offices contain all the necessary basic mapping data and the land boundary or cadastral survey data. The Land Information Centre of the Survey and Mapping Office has completed the digitisation of the basic 1:1 000 survey sheets. The conversion work of the land boundary record is proceeding district by district, enabling the phased implementation of the district systems. The main benefits of using the systems are that many jobs can now be performed in a shorter time and the quality of the products is also improved because of the timeliness of the land information and the wide choice of plan sizes, scales, and colours available. As with the hard copy maps, digital maps at 1:1 000 and 1:20 000 are now on sale at the Land Information Centre. Digital maps are widely used by public utility companies, engineering consultants and construction firms.

The Photogrammetric Survey Section provides aerial photographs and photo- grammetric mapping as well as digital 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 record photography after storms, landslides and aircraft crashes.

The Land Survey Ordinance was enacted in May 1995 and will be fully imple- mented by January 1996. It controls the quality of land division surveys which can be done only by Authorised Land Surveyors.

Drainage Services

The Drainage Services Department is responsible for planning, designing, con- structing, operating and maintaining the sewerage, sewage treatment and stormwater drainage infrastructures.

Treatment and Disposal of Foul Water

The treatment and disposal of foul water, including domestic sewage and trade and industrial effluent, are based on standards, strategies and programmes drawn up by the Environmental Protection Department. Planning, design and construction of the associated projects are carried out by the Drainage Services Department.

Foul water disposal projects are broadly divided into three categories: sewerage or sewage treatment projects which were in the public works programme before the new strategy to combat water pollution evolved; 'sewerage masterplan schemes' which are 16 territory-wide sewerage rehabilitation and improvement projects; and the 'Strategic Sewage Disposal Scheme' under the new strategy. The latter is a massive project to collect, treat and discharge all sewage from Hong Kong Island, Kowloon, Tsuen Wan, Kwai Chung and Tseung Kwan O into carefully selected waters.