Report No. : GEO Report No. 141

Report Title : Evaluation of the Effectiveness of Squatter Clearance Actions in Reducing Landslide Risk (2003), 32 p.

Author : W.M. Cheung & Y.K. Shiu

Abstract

Since the establishment of the Geotechnical Control Office in 1977 (renamed as the Geotechnical Engineering Office in 1991), there have been concerns about the safety of squatters living on steep hillsides. Various clearance actions have been taken by the Government to reduce landslide risk to squatters. They include (i) Emergency Clearance (EC) due to landslides, (ii) Non Development Clearance (Slope Safety) (NDC) Programme, and (iii) Development Clearance (DC) Programme.

The objective of this study is to evaluate the effectiveness of the various squatters clearance actions in respect of landslide risk reduction to squatters up to September 2001. The technique of expert opinion has been used in an attempt to quantify the apportionment of landslide risk reduction associated with the respective squatter clearance actions. The results of the study show that the landslide fatality rate has been reduced by about 90% since the mid 1980s. This reduction is largely attributable to the combined effects of the squatter clearance actions. Based on the judgement of the expert panel formed for this study, the relative contributions in reducing landslide fatality rate attributable to the EC, NDC and DC Programmes are about 27 to 29%, 14 to 18%, and 57 to 55% respectively.

The landslide risk posed to squatters presented in this study is reflected by the historical fatality rates. As such, it should not be regarded as being equivalent to landslide risk calculated in a formal quantitative risk assessment because 'near-miss' events would not have been fully considered.

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