Report No. : GEO Report No. 347

Report Title : Factual Report on Hong Kong Rainfall and Landslides in 2018 (2022), 81 p.

Author : R.C.T. Wai, R.W.H. Lee & E.K.H. Chu

Abstract

This report presents a summary of the factual information on rainfall and landslides in Hong Kong throughout 2018. 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 2018 at the HKO's Principal Raingauge at Tsim Sha Tsui amounted to 2162.9 mm, a deficit of about 10% comparing to the mean annual rainfall of 2398.5 mm between 1981 and 2010. No Black Rainstorm Warning was issued in 2018. Four Red Rainstorm Warnings and 27 Amber Rainstorm Warnings were issued between 8 June and 16 September 2018, and between 6 June and 24 September 2018 respectively.

Three Landslip Warnings were issued on 7 June, 29 August and 16 September 2018. A total of 346 incidents were reported to the Government in 2018. Of these, 253 were classified as genuine landslides and 12 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 16 landslides in 2018 with notable consequences. Of these landslides, one resulted in damage of a storage structure, a container and several vehicles as well as temporary closure of a road, one led to a permanent evacuation of a squatter dwelling, two led to temporary evacuation of squatter dwellings and three resulted in damage of vehicles. The remaining nine landslides resulted in temporary closure of roads. Other landslides in 2018 primarily affected open areas, footpaths or minor access roads, catchwaters and a construction site without any significant direct or indirect consequence. No fatality was reported as a result of the landslides.

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