LCQ11: Measures to prevent landslides

Following is a question by the Hon Ip Kwok-him and a written reply by the Secretary for Development, Mr Paul Chan, in the Legislative Council today (April 27):

Question:

It has been reported that the Hong Kong Observatory has forecast that the rainfall in Hong Kong this year will be higher than that in previous years, and the Geotechnical Engineering Office (GEO) has also forecast that the number of landslide incidents for the year will correspondingly increase. GEO will therefore carry out works so that slopes can better withstand severe rainstorms. In this regard, will the Government inform this Council:

(1) of the respective current numbers of man-made slopes and natural hillsides on government lands and private lands; whether the Government will, in light of the aforesaid forecasts, carry out comprehensive assessment on the stability of those slopes prior to the onset of the rainy season this year to protect the lives and safety of members of the public; if it will, of the relevant timetable; if not, the reasons for that;

(2) given that in 2014, a big tree collapsed from a slope inside a private residential estate at Robinson Road and fell onto a footpath, crushing a passing pregnant woman to death, whether the Government will take relevant precautionary measures in public places (e.g. bus stations and public light bus stations) with heavy pedestrian flows and adjacent to slopes prior to the onset of the rainy season this year to safeguard public safety; if it will not, of the reasons for that; if it will, apart from issuing notices to the relevant private lot owners to remind them of their responsibilities, what other measures the Government will take in respect of places adjacent to slopes on private lands, and what measures the Government will take in respect of places adjacent to man-made slopes and natural hillsides on government lands; and

(3) whether it has compiled statistics on the current number of dangerous slopes across the territory which were formed as a result of fly-tipping of soil; if it has, of the number of such slopes which are in danger of collapse; whether the Government will hydroseed the surface layers of those slopes to reinforce them with vegetation; if it will not, of the reasons for that?

Reply:

President,

The Government has been paying close attention to the risk of landslide and has strived to improve slope safety. To this end, we have adopted a risk-based priority ranking system to ensure that the most deserving man-made slopes and natural hillside catchments are selected for action under the Landslip Prevention and Mitigation Programme (LPMitP). Our reply to the three parts of the questions is as follows:

(1) and (2) There are about 60 000 registered man-made slopes in Hong Kong, of which about 40 000 are government man-made slopes while the remaining 20 000 are of private responsibility. The number of natural hillside catchments with known hazards and located close to existing buildings and important transport corridors amounts to about 2 800.

The departments responsible for slope maintenance carry out regular maintenance inspections and, where necessary, maintenance works on all government man-made slopes and all hazard mitigation measures implemented on natural hillsides. These maintenance departments also adopt precautionary actions against heavy rainfall and endeavour to complete the necessary regular maintenance inspection and maintenance works before the onset of the wet season each year. For private slopes, their owners are responsible for the inspection and maintenance works. In this connection, the Civil Engineering and Development Department will continue with its public education programme to remind owners of private slopes the importance of slope inspection and maintenance. Relevant public education will be stepped up prior to the onset of the wet season, including media briefings on slope safety, written reminders to private slope owners, exhibitions on slope safety and special Announcements in the Public Interest (APIs) for TV and radios.

In addition to the above precautionary measures before the wet season, the Government will continue to upgrade 150 government man-made slopes, implement risk mitigation works for 30 natural hillside catchments and conduct safety-screening for 100 private man-made slopes each year under the LPMitP. In accordance with the risk-based selection principle, priority will be given to slopes located in close vicinity of public facilities with heavy pedestrian flows (such as bus shelters).

The Greening, Landscape and Tree Management Section (GLTMS) of the Development Bureau has been actively coordinating and promoting proper tree care. By disseminating information on the Internet, TV APIs and seminars, the owners are made aware of their responsibilities and ways for proper tree care. The GLTMS has recently published a Handbook on Tree Management, with guidelines and practice notes on tree management, for information of the owners to help them enhance their work in tree care. Furthermore, apart from issuing letters to owners and property management companies in January 2016 to remind them to conduct tree inspections and carry out mitigation measures as appropriate before the wet season, the GLTMS also conducted four public seminars on "Tree Care before Wet Season" in March and April to enhance the knowledge of public in proper tree care. The GLTMS is committed to disseminating the information on proper tree care to all stakeholders.

For trees on government man-made slopes and natural hillsides, the tree management departments will follow the requirements stipulated in the Guidelines for Tree Risk Assessment and Management Arrangement (the TRAM Guidelines) as published by the GLTMS and undertake tree risk assessments and appropriate mitigation measures at least once a year before the onset of the wet season to ensure public safety. Illustrations showing different location types of trees on slopes are included in the latest revised TRAM Guidelines for easy reference of tree inspection officers and to prompt them to pay particular attention to tree stability and root anchorage during tree inspections.

(3) The Government does not have any data on the dangerous slopes formed by fly tipping. On receipt of a complaint about fly tipping that have slope safety implications, the Geotechnical Engineering Office (GEO) will assess the situation. For cases with potential risk of landslide that may endanger the public, the GEO will provide professional advice and assistance to the relevant departments, including the Buildings Department, Environmental Protection Department, Planning Department and Lands Department, for their follow-up actions. Generally, hydroseeding alone cannot stabilise substandard slopes.

Ends/Wednesday, April 27, 2016
Issued at HKT 11:31

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