LAND, PUBLIC WORKS AND UTILITIES
statutory procedures to make way for the implementation of the Stage II works. The completed project will provide a higher flood protection level to the communities along the river.
The Land Drainage Ordinance is an essential component of the strategy to alleviate flooding in the New Territories. It authorises government staff to gain access to, inspect, clear and maintain main watercourses running through or bordering on private land, in a further attempt to reduce the risk of flooding. It also empowers the government to control the erection of structures within main watercourses, to ensure their water-carrying capacity is not undermined. The ordinance is now effective in the Yuen Long, Kam Tin, Ngau Tam Mei and Indus drainage basins. It is planned to implement the ordinance in San Tin, Ganges and Tin Shui Wai drainage basins by the end of 1996.
Operation and Maintenance of the Drainage System
The volume of sewage treated by the department has increased from 385 million cubic metres in 1989 to 670 million cubic metres in 1995, of which 146 million cubic metres receive full biological treatment. This is handled by 80 sewage pumping stations and 66 sewage treatment plants throughout the territory.
Since the establishment of the department, the approach to the operation and maintenance of the public drainage system has progressively shifted from crisis management to preventive maintenance. The efficient maintenance of the drainage infrastructure is essential to ensure the proper and effective disposal of foul and storm water, and to prevent blockages and leaks which also cause bad odours, flooding or other nuisances to the public.
The department maintains more than 3 000 kilometres of watercourses, drains and sewers. Some 50 000 clearance exercises are carried out annually to remove more than 300 000 cubic metres of silt from drains and watercourses, to keep them free-flowing and their pollution level low. A 24-hour hotline service operates to receive complaints on blocked drains and sewers.
The department also operates an Emergency Storm Damage Organisation. It is run by staff on a rotational basis and is supported by the department's own labour force and contractors. Its operation ensures that emergency situations are dealt with efficiently.
Recurrent expenditure on operations and maintenance in 1994–95 was $644 million. This sum is increasing steadily.
Geotechnical Engineering
The Geotechnical Engineering Office (GEO) of the Civil Engineering Department was established after the landslip disasters of the 1970s. The control of geotechnical aspects of construction works, to reduce landship risk by geotechnical checking, continues to be its foremost duty in terms of staff deployed. Checks were made on 9 314 design proposals during the year.
Works to upgrade unsatisfactory old man-made slopes are continuing at an increased rate. Five consultancies are in place to accelerate the Landslip Preventive Measures (LPM) Programme to complete the necessary upgrading works for slopes in the 1977-78 Slope Catalogue by the year 2000. During 1995, a total of $175 million was spent on the LPM programme. Landship preventive works were completed on 60
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