Report No. : GEO Report No. 97
Report Title : Hong Kong Rainfall and Landslides in 1997 (1999), 271 p. plus 2 drgs.
Author : T.W.K. Lam
This Report presents a review of rainfall and landslides in Hong Kong throughout 1997. Rainfall information has been obtained from the Geotechnical Engineering Office (GEO) automatic raingauge system and from the Hong Kong Observatory (HKO). Most of the landslide data have been taken from the records of incidents reported to the GEO in 1997. Supplementary data have been obtained from the GEO's 1997 Landslide Investigation Consultants and other Government Departments.
1997 was the wettest year at the Hong Kong Observatory (HKO) since records began in 1884. Rainfall at the HKO amounted to 3343.0 millimetres, 51% above normal and exceeding the previous record set in 1982. The most intense maximum 24-hour rainfall of 799.0 millimetres was recorded at the Chinese University (CU) on 2 and 3 July. The annual rainfall at the CU amounted to 4391.0 millimetres. The maximum annual rainfall of 4907.0 millimetres was recorded at Tai Mo Shan.
Eight Landslip Warnings were issued in 1997. The rainstorms in 1997 resulted in 543 incidents being reported to the GEO, 491 of which were classified as genuine landslides, and 50 of which were major (i.e. an event with a volume of collapsed mass of 50 m3 or more, or where a fatality has occurred). Two fatalities and nine injuries occurred. The consequences resulting from the landslides included the temporary evacuation of 47 squatter huts, 19 houses and 14 flats, the permanent evacuation of 115 squatter huts, and 120 landslides resulted in the blockage of sections of road, pedestrian pavement and/or access.
Report SPR 7/98 provides more detailed information on the rainfall and landslides associated with the rainstorm of 1-4 July 1997.