Sains Malaysiana 52(7)(2023): 1939-1954

http://doi.org/10.17576/jsm-2023-5207-04

Peta Ketumpatan Fizikal bagi Menentukan Unsur Berisiko Banjir Di Kawasan Kota Belud, Sabah, Malaysia

(Physical Density Map for Determining Flood Risk Elements in Kota Belud Area, Sabah, Malaysia)

KAMILIA SHARIR^1,2 & RODEANO ROSLEE^1,2*

¹Natural Disaster Research Centre (NDRC), Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia

²Faculty of Science & Natural Resources (FSSA), Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia

Received: 28 April 2022/Accepted: 12 July 2023

Abstrak

Banjir merupakan bencana alam yang berlaku setiap tahun dan memberi impak kepada kehidupan manusia, gangguan sosio-ekonomi dan kemusnahan alam sekitar. Terdapat tiga komponen penting dalam mentafsir risiko banjir iaitu; Bahaya, Kemudahterancaman dan Pendedahan. Pendedahan dalam konteks ini merujuk kepada unsur yang terdedah atau berisiko kepada sesuatu kerugian dan mempunyai tahap kemudahterancamannya yang tersendiri. Rekod kejadian banjir di kawasan ini semakin meningkat terutamanya selepas kejadian Gempa Bumi Ranau 2015. Peningkatan kejadian ini menjejaskan kelangsungan hidup kerana kebergantungan komuniti setempat terhadap hasil pertanian seperti penanaman padi untuk menjana pendapatan selain penempatan kemudahan fasiliti awam seperti hospital, pejabat kerajaan dan sekolah. Justeru, mengenal pasti unsur berisiko di kawasan ini amatlah penting untuk meminimumkan risiko banjir yang akan menjejaskan kawasan ini. Objektif utama kajian ini adalah untuk mengenal pasti unsur berisiko yang terdedah kepada ancaman bencana banjir di kawasan Kota Belud, Sabah. Pendedahan unsur berisiko boleh dikenal pasti secara nyata atau tidak nyata. Unsur berisiko nyata dikenal pasti melalui jejak bangunan dan jenis jaringan jalan raya yang ada di sekitar kawasan kajian manakala unsur berisiko tidak nyata pula, analisis ini dilakukan secara soal selidik di lapangan. Peta Ketumpatan Fizikal (PKF) kemudian dihasilkan daripada jejak bangunan dan peta jaringan jalan raya untuk menggambarkan unsur berisiko pada skala rantau. Peta ini dihasilkan dengan menukar poligon bangunan menjadi titik dan pengiraan dibuat berdasarkan kilometer persegi dan menggabungkannya dengan maklumat ketumpatan jaringan jalan raya. Kaedah ini turut digunakan sebagai kaedah alternatif untuk menggambarkan taburan penduduk bagi kawasan yang mempunyai ketersediaan dan kebolehcapaian data yang terhad. Hasil analisis menunjukkan kawasan unsur berisiko yang berketumpatan fizikal tinggi terletak berhampiran dengan sungai-sungai utama seperti Sungai Kadamaian, Sungai Wariu, Sungai Gurong-gurong, Sungai Tempasuk dan Sungai Abai. Kajian ini amat berguna sebagai kajian perintis dalam mentafsir risiko banjir di kawasan ini dan berpotensi dikembangkan di kawasan lain agar kerosakan dan kerugian harta benda, infrastruktur atau utiliti awam dapat diurus dan dikurangkan.

Kata kunci: Bahaya; banjir; kemudahterancaman; Kota Belud; risiko; unsur berisiko

Abstract

Flooding is a natural disaster that annually impacts human lives, socio-economic disruptions, and environmental destruction. There are three critical components to interpreting flood risk: Hazard, vulnerability, and exposure. Exposure in this context refers to elements that are exposed or at risk of experiencing losses and have their level of vulnerability. The record of flood incidents in this area is increasing, especially after the Ranau Earthquake 2015. This increase in incidents affects livelihoods as the local community relies on agricultural yields such as rice cultivation for income generation, in addition to the presence of public facilities such as hospitals, government offices, and schools. Therefore, identifying the risky elements in this area is crucial to minimising the flood risk that may affect the region. The main objective of this study was to identify the elements at risk from flood disaster threats in the Kota Belud area of Sabah. Risk elements can be identified explicitly or implicitly. Explicit risk elements are identified through the presence of buildings and the types of road networks in the study area, while implicit risk elements are analysed through field surveys. A Physical Density Map (PDM) is then generated from the building footprints and road network map to illustrate the risk elements at a regional scale. This map is created by converting building polygons into points, calculating them based on square kilometres, and combining them with road network information. This method is also an alternative approach to depicting population distribution in areas where data availability and accessibility are limited. The analysis results show that high physical density risk elements are located near major rivers such as Sungai Kadamaian, Sungai Wariu, Sungai Gurong-gurong, Sungai Tempasuk, and Sungai Abai. This study is precious as a pioneering study in interpreting flood risk in this area. It has the potential to be extended to other areas to manage and reduce damages and losses to properties, infrastructure, or public utilities.

Keywords: Element at risk; flood; hazard; Kota Belud; risk; vulnerability

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*Corresponding author; email: rodeano@ums.edu.my