ENG-1995 — Page 266

LAND, PUBLIC WORKS AND UTILITIES

The extensive collection of historical and recent aerial photographs was supplemented by satellite data. These were used to monitor suspended sediment offshore and for studies of areas affected by landslips. Engineering geological studies are under way on slopes near Tung Chung new town, presently under construction in North Lantau.

The GEO's Geotechnical Information Unit (GIU) houses the largest collection of geotechnical data in Hong Kong. It served more than 8 800 users during the year.

Further major ground investigations were undertaken for main drainage channels in the New Territories and north-east Lantau development studies. In all, more than 240 land and marine ground investigations (including geophysical surveys) and over 120 laboratory test schedules were completed. Additional ground investigation and laboratory testing term contracts were let for the accelerated LPM Programme.

The GEO manages the Public Works Central Laboratory at Kowloon Bay and seven Public Works Regional Laboratories in various parts of the territory. These laboratories are accredited under the Hong Kong Laboratory Accreditation Scheme (HOKLAS) to carry out specific tests on construction materials and to provide laboratory calibration services. More than 90 tests have been accredited. A new section of the laboratory has been set up to extend the services to cover rock mechanics testing.

The GEO provides geotechnical advisory services to government departments. In 1995, it undertook detailed geotechnical design for 120 capital works projects and provided advice on the geotechnical aspects for 160 projects.

Fill Management

The territory's fill resources are managed by the Fill Management Committee, whose secretariat is a division of the Geotechnical Engineering Office. The committee was set up in 1989 to make decisions on the reservation, allocation and efficient utilisation of fill resources for government and major private projects. It consists of representatives from a broad spectrum of government departments and policy branches involved in the development of the territory.

From the beginning of 1990 up to the end of 1995, about 235 million cubic metres of marine fill and 150 million cubic metres of land-based fill had been used for reclamation projects. A further 375 million cubic metres of fill from both land and marine sources are needed for reclamations over the next 10 years. The committee will continue to identify suitable fill sources to meet project requirements, with considerable attention being focused on the supply of sand from waters outside Hong Kong.

A second role of the committee is to plan the marine disposal of dredged mud, including contaminated mud, and to allocate disposal capacity at the gazetted marine spoil grounds. During the year under review, approximately 30 million cubic metres of uncontaminated mud and 2.2 million cubic metres of contaminated mud were disposed of under licences issued by the Environmental Protection Department. The uncontaminated mud was dumped in submarine spoil grounds and in worked-out marine borrow pits, and the contaminated mud was placed in disposal pits especially designed to ensure containment.

In connection with the management of the territory's fill resources and mud disposal capacity, the GEO, on behalf of the Fill Management Committee, continues

219