The Emerging Widespread Debris Flow Disasters in Tropical Terrain of Peninsular Malaysia: Understanding the Risk and Policy Intervention

¹ Institute of Geology Malaysia, 43600 UKM, Bandar Baru Bangi, Malaysia
² Geomapping Technology Sdn Bhd, 43000 Kajang, Malaysia
³ Academy of Professors Malaysia, 62000 Putrajaya, Malaysia
⁴ Geopark & Geotourism Creative Solutions Sdn Bhd, 43000 Kajang, Malaysia
⁵ Department of Mineral and Geoscience Malaysia, 62000 Putrajaya, Malaysia
⁶ Universiti Tenaga Nasional, Institute of Energy Infrastructure (IEI), 43000 Kajang, Malaysia
⁷ Universiti Teknologi Malaysia, Disaster Preparedness and Prevention Centre (DPPC), Malaysia-Japan International Institute of Technology, 54000 Kuala Lumpur, Malaysia
⁸ Universiti Kebangsaan Malaysia, Institute for Environment and Development (LESTARI), 43600 Bandar Baru Bangi, Malaysia

^* Corresponding author: arjaapar@gmail.com

Abstract

Several widespread debris flow disasters stroke Peninsular Malaysia in between 2021 and 2022, scattered across the country. It was the first time for this hazard being nationally recognised as a type of geological disaster in the country. Debris flow disaster is not a new phenomenon. It had been recorded since 1995, however, in the past they were isolated incidents and did not attract much attention. The recent widespread debris flow disasters started in Gunung Jerai, Kedah on 18 August 2021; followed by similar incidents but in 3 different states concurrently in (1) Bentong, Pahang, (2) Hulu Langat, Selangor, and (3) Jelebu, Negeri Sembilan on 18 December 2021; Kenyir, Terengganu on 27 February 2022; and finally at Gunung Inas, Kedah on 4 July 2022. These disasters sparked numerous technical and social issues where heated debates on whether they were purely due to natural processes or caused anthropogenic activities. Previously, debris flow phenomena in Malaysia were so rare, that the term ‘debris flow’ was not familiar to the lay public. The term of “debris flow” was often disregard or used interchangeable with ‘water surge’ phenomena by the media and public, especially for sudden sediment water surge from hilly upstream after intense rainfall at hillside river catchment areas, normally occurs during the monsoon season. The ordinary water surge has significantly lesser level of destruction and momentum as compared to a debris flow with higher debris-type sediments. This paper discusses the emerging issues of debris flow in Malaysia and some initiatives being carried out in in facing the geohazard. The Department of Mineral and Geoscience Malaysia and a team of local geohazard experts have taken the lead to carry out studies to understand the sudden emergence of widespread and cascading debris flow events in Malaysia. As a result, proposal on policy intervention was put forward to the relevant government ministries; post-disaster programme has been continuously carried out to educate the communities on the geological disaster risks through community-based disaster risk management (CBDRM).