Report No. : GEO Report No. 345

Report Title : Factual Report on Hong Kong Rainfall and Landslides in 2017 (2022), 78 p.

Author : R.C.T. Wai, R.W.H. Lee & V.W.W. Kong

Abstract

This report presents a summary of the factual information on rainfall and landslides in Hong Kong throughout 2017. Rainfall information was obtained from the Hong Kong Observatory (HKO) to supplement the information available in the Geotechnical Engineering Office (GEO). Details of the landslides were obtained from records of landslide incidents reported to the GEO. Supplementary information was collected from the Agriculture, Fisheries and Conservation Department, Architectural Services Department, Drainage Services Department, Highways Department, Housing Department, Lands Department, Water Supplies Department, and the GEO's landslide investigation consultants, namely Fugro Hong Kong Limited and AECOM Asia Company Limited.

Rainfall recorded in 2017 at the HKO's Principal Raingauge at Tsim Sha Tsui amounted to 2572.1 mm, a surplus of seven percent comparing to the mean rainfall of 2398.5 mm between 1981 and 2010. One Black Rainstorm Warning was issued on 24 May 2017. Five Red Rainstorm Warnings and 24 Amber Rainstorm Warnings were issued between 24 May and 3 August 2017, and between 21 April and 17 October 2017 respectively.

Four Landslip Warnings were issued on 24 May, 13 June, 17 July and 27 August 2017. A total of 188 incidents were reported to the Government in 2017. Of these, 152 were classified as genuine landslides and eight of them were designated as major failure (i.e. with a failure volume of 50 m³ or more, or where a fatality has occurred).

There were eight landslides in 2017 with notable consequences. Of these landslides, one led to minor injury of a villager due to fallen bricks as well as temporary evacuation of a squatter dwelling and two other led to temporary evacuation of one squatter dwelling and five squatter dwellings respectively. The remaining five landslides resulted in temporary closure of roads. Other landslides in 2017 primarily affected open areas, footpaths or minor access roads, catchwaters and construction sites without any significant direct or indirect consequence. No fatality was reported as a result of the 2017 landslides.

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