Landslide mapping and characterization for agriculturally intensive mountainous region of Cameron Highlands, Malaysia


Author : Afiq F.A. Rahim, Abd Rasid Jaapar, Zakaria MohamadPublication : Bulletin of the Geological Society of MalaysiaNumber : 72Page : 177 - 190Year : 2021DOI : doi.org/10.7186/bgsm72202114


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Bulletin of the Geological Society of Malaysia, Volume 72, November 2021, pp. 177 - 190

Landslide mapping and characterization for agriculturally intensive mountainous region of Cameron Highlands, Malaysia

Afiq F.A. Rahim*, Abd Rasid Jaapar, Zakaria Mohamad

Geoscience Department, Geomapping Technology Sdn. Bhd., 806A & 807A (1st floor), Kompleks Diamond, Jalan Seksyen 1/16, Seksyen 1, 43650 Bandar Baru Bangi, Selangor, Malaysia
* Corresponding author email address: afiqfarhan9507@gmail.com

Abstract: Relatively cool tropical climate with high annual rainfall experienced in mountainous tropical region creates favorable agricultural areas where intensive agricultural practices often correlate with increasing landslide events. While it has long been associated with landslides, agricultural practice in such areas especially in Cameron Highlands, Malaysia continues to flourish with minimal regard to environmental sustainability and safety. Therefore, this study aims to confirm the relationship between human activities and landslide occurrences and identify human practices that directly or indirectly cause landslides. Aerial photograph was used to identify landslides and anthropogenic features while other remotely sensed data including Interferometric Synthetic Aperture Radar (IFSAR) were used to establish the geomorphology of study area. A total of 207 landslides were identified in a 25 km2 area from remote sensing study and field mapping. They were superimposed over several potential contributing factors including geology, slope gradient and human activities. This study found that landslides are more likely to occur in areas greater than 15° of slope angle. The main factor, however, is the human factor where 164 landslides (79.22% of total identified landslides) were located in agricultural lands. Poorly planned and engineered agricultural farms were identified as the main causal factors for landslide occurrences at the study area, either directly or indirectly. These issues were observed through remote sensing study using aerial photograph which were then verified through site observations. New district development plan called for a stricter regulations in new tourism and agricultural developments. Improvements should also be implemented on existing agricultural activities where most of these landslides were located at this area. Therefore, in addition to controlling new developments, improving of existing agricultural practices in Cameron Highlands shall be a major focus in ensuring slope safety and their sustainability.

Keywords: Landslide, Cameron Highlands, agriculture

Abstrak: Iklim tropika yang relatifnya sejuk dengan taburan hujan tahunan yang tinggi di kawasan pergunungan tropika membentuk kawasan pertanian yang sesuai di mana praktis pertanian tersebut sering kali dikaitkan dengan peningkatan peristiwa tanah runtuh. Walaupun telah lama dikaitkan dengan tanah runtuh, praktis pertanian di kawasan tersebut khususnya di Cameron Highlands, Malaysia terus berkembang dengan pertimbangan minimum terhadap kelestarian dan keselamatan alam sekitar. Justeru, kajian ini bertujuan untuk mengesahkan hubung kait antara aktiviti manusia dan kejadian tanah runtuh serta mengenal pasti praktis manusia yang secara langsung atau tidak langsung menyebabkan tanah runtuh. Imej fotoudara digunakan untuk mengenal pasti tanah runtuh dan fitur antropogenik manakala data penderiaan jauh yang lain seperti Radar Interferometrik Bukaan Sintetik (IFSAR) digunakan untuk menentukan geomorfologi kawasan kajian. Sejumlah 207 tanah runtuh dikenal pasti daripada kawasan seluas 25 km2 menerusi kajian penderiaan jauh dan pemetaan lapangan. Tanah runtuh tersebut ditindih di atas beberapa faktor penyumbang yang berpotensi termasuk geologi, kecuraman cerun dan aktiviti manusia. Kajian ini mendapati tanah runtuh lebih cenderung untuk berlaku di kawasan dengan sudut cerun melebihi 15°. Namun, faktor utama adalah faktor manusia di mana 164 tanah runtuh (79.22% daripada jumlah tanah runtuh yang dikenal pasti) terletak di dalam tanah pertanian. Ladang pertanian yang tidak dirancang dan direka dengan baik dikenal pasti sebagai faktor penyumbang utama untuk kejadian tanah runtuh di kawasan kajian, sama ada secara langsung atau tidak langsung. Isu-isu tersebut dicerap menerusi kajian penderiaan jauh menggunakan fotoudara yang kemudiannya disahkan menerusi cerapan lapangan. Rancangan tempatan daerah terbaharu mencadangkan peraturan yang lebih ketat untuk pembangunan pertanian dan pelancongan baharu. Penambahbaikan juga perlu dilaksanakan pada aktiviti pertanian sedia ada di mana kebanyakan tanah runtuh terletak di kawasan tersebut. Justeru, sebagai tambahan kepada kawalan terhadap pembangunan baru, membaiki praktis pertanian sedia ada di Cameron Highlands sepatutnya menjadi fokus utama dalam memastikan keselamatan cerun dan kelestariannya.

Kata kunci: Tanah runtuh, Cameron Highlands, pertanian

DOI: https://doi.org/10.7186/bgsm72202114