The Drainage Services Department (DSD) is implementing a series of major flood control projects in the New Territories and in West Kowloon, costing about $12 billion.

In the north-western New Territories, construction works for improving about 10 kilometres of the middle and lower reaches of the Kam Tin River and the Shan Pui River in Yuen Long have been completed. Construction of about nine kilometres of drainage channels for the upper reaches of the Kam Tin River and the Ngau Tam Mei stream has been in progress since 1999. Design work for another 23 kilometres of new river channels is under way, including the Yuen Long Bypass Floodway, the upper reaches of the Kam Tin River, the Ngau Tam Mei stream and the San Tin drainage channel.

In the northern New Territories, the most critical flood mitigation project is the Shenzhen River Regulation Project, which aims to improve the downstream outlet for several major rivers in the area, such as the River Indus and the River Beas. Stage I and II works were completed in April 1997 and June 2000 respectively. Planning and design for Stage III works were in hand, with construction scheduled to commence in 2001 for completion in 2005. Corresponding improvement works for the River Indus and the River Beas had also started, to match the Stage II works.

On completion of these river training works, flood prevention measures in the New Territories will be greatly improved.

In addition to the major river training works, village flood protection schemes were also implemented to protect low-lying villages, which are lower than the drainage channels, from flood hazards. These schemes consist of a protective earth bund encompassing the village, a flood storage pond and a flood water pumping station. Flood water within the protected area is collected in the flood storage pond for pumping into the drainage channels outside the bund. To date, 19 such schemes are in operation and another six schemes are at various stages of planning and design.

In West Kowloon, good progress is being made on the Stage I drainage improvement works, which are scheduled for completion in 2003. Stage II works had commenced in December 1999 for completion in 2004. In order to minimise the occurrence and extent of road openings caused by the extensive drainage improvement works, construction works for a flood storage tank underneath the Tai Hang Tung Recreation Ground and a 1.8-kilometre stormwater transfer tunnel from Kowloon Tong to the Kai Tak Nullah will start in early 2001 for completion in 2004. The underground flood storage tank will have a capacity of 100 000 cubic metres.

The DSD has also completed seven Drainage Master Plan Studies to review the condition and performance of the existing stormwater drainage systems in various flood-prone areas in Hong Kong. Both long-term and short-term measures to upgrade the system to cope with current and future development needs would be devised.

The department operates a preventive maintenance programme whereby the public drainage system is regularly inspected and desilted before and during the rainy seasons. This ensures the effective discharge of stormwater, and prevents blockages and overflows which may cause flooding and nuisance to the public.

In 2000, the DSD maintained over 2 200 kilometres of watercourses, river channels and drains. About 400 000 cubic metres of silt from drains and watercourses were removed in order to keep them free from blockages. To provide effective drainage services, a 24-hour drainage complaint hotline service was operated to receive complaints from the public on blocked drains. The department also operated an Emergency and Storm Damage Organisation to ensure that emergency situations could be dealt with speedily and efficiently.

The department strives for continuous improvement of its services by undertaking various public education activities on flood prevention through roving exhibitions with video shows at popular shopping centres, wide distribution of promotional leaflets and pamphlets, media site visits and press conferences. Since the launching of an 'Outreach Programme' in September 1999, engineers have visited more than 50 secondary schools and held seminars with the students to increase awareness of flood prevention work.

The Geotechnical Engineering Office (GEO) was established after landslip disasters in the 1970s. Its main duties are the control of geotechnical aspects of construction works and upgrading of substandard slopes to reduce landslip risk.

In 2000, geotechnical checks were made on 12 930 design proposals. A total of $850 million was spent on the Landslip Preventive Measures Programme. Upgrading works were completed on 250 government slopes and safety screening was completed on 309 private slopes.

The slope cataloguing work under the 'Systematic Identification and Registration of Slopes in the Territory' project had been completed, and regular updating of the Government's Slope Catalogue will continue. The 'Systematic Identification of Maintenance Responsibility of Slopes' project was completed at the end of 1999, and the database opened for public access. A new computerised Slope Information System (SIS) had been compiled, and it contains important information on all sizeable man-made slopes and retaining walls in Hong Kong. Public access to the information on the 54 000 slopes in the SIS had been enhanced by the launch of the English and Chinese versions of the SIS on the Internet at the Hong Kong Slope Safety web site (http://hkss.ced.gov.hk) in March 1999 and March 2000 respectively. The web site has also been enhanced to include more slope safety related information.

In order to provide a more efficient and effective landslip emergency service, the GEO has developed and installed a computerised information system to facilitate the collection and dissemination of landslip information. This enhancement can significantly improve the co-ordinated efforts among departments to deal with landslide incidents.

Another duty of the office is to inspect the hillside squatter villages and to recommend rehousing of squatters living in structures that are most vulnerable to landslips. Upon the GEO's recommendation, more than 74 500 squatters at landslide risk had been rehoused. In 2000, GEO had inspected about 5 000 squatter structures.

The office continued with its studies on natural terrain landslides to improve the ability to assess natural terrain hazards. Guidelines were issued in 2000 for trial use by the geotechnical profession in assessing and mitigating natural terrain landslide hazards. An area-based study of the natural terrain hazards affecting the Tsing Shan Foothills region in Tuen Mun was being carried out.

The GEO continued with its public education campaigns on slope maintenance and slope safety warnings by, inter alia, wide distribution of promotional booklets and pamphlets, attending media interviews and public seminars, and mounting displays at popular shopping centres. TV broadcasting of announcements of public interest continued on the issues of private slope maintenance; personal precautionary measures while landslip warnings are in effect and the problems of unauthorised cultivation on slopes. A training video for government slope maintenance personnel and a teaching kit on slope safety for secondary schools had been produced. To further enhance public education on slope safety, an independent review of the existing public education work, together with the formulation of a long-term strategy, will be completed by January 2001. The Community Advisory Unit continued to provide useful advice to private slope owners to help them maintain and improve their slopes.

During the year, the GEO completed a study on the use of geophysical investigation techniques to assist in the identification of weak soils that may adversely affect slope stability. Two geophysical methods were found to be useful and were introduced for use in selected landslide and slope studies. A magnetic survey was completed for Hong Kong waters, and this provided improved regional perspective on faults and other geological structures. Two new geological memoirs, presenting a comprehensive review of the geology of Hong Kong, were published.

The Geotechnical Information Unit in the Civil Engineering Library houses the largest collection of geotechnical data in Hong Kong. It is open to the public, and served more than 36 000 users during 2000.

The GEO provides material testing and ground investigation services to support land production and infrastructure projects. The Public Works Laboratories (PWL) operated by the office (consisting of the Public Works Central Laboratory at Kowloon Bay and six Public Works Regional Laboratories in various parts of Hong Kong), carry out specific tests on construction materials and provide calibration tests. In 2000, some 410 000 tests were carried out through the PWL and in the GEO's ground investigation term contracts, and the length of soil and rock drilled totalled 9 600 metres.

In 2000, the GEO continued to provide specialist geotechnical advisory services to government departments. The intent of the services is to help government departments achieve a high standard of geotechnical works and to assist them to find cost-effective solutions. These services include the provision of ad-hoc geotechnical advice and carrying out feasibility studies, detailed investigations, design and construction supervision for a wide range of public works projects, such as road improvement works at Ap Lei Chau North Coastal Road and Clearwater Bay Road; road widening and footbridge improvement works at Ap Lei Chau Bridge Road; road widening works and mitigation of natural terrain landslides at Tsing Yi North Coastal Road, Yam O Tuk Service Reservoirs and the Teleport project at Chung Hom Kok; boulder and slope stabilisation works at Tseung Kwan O Area 137 and Yung Shue Wan; reclamation works at North Tsing Yi; regulation works (Stage III) at Shenzhen River; and flood protection works at East San Tin and other regions in the north-western New Territories.

The Slope Maintenance Audit Section of the GEO continued to assist maintenance departments to improve their performance in discharging their slope maintenance responsibilities. First-round audits of government slope maintenance works had been completed, and identified improvements had been substantially implemented by the maintenance departments. The second-round audits will begin in early 2001.