Case Studies with Innovative Technology

   doi:10.3850/978-981-07-0188-8_P093

ABSTRACT

Oblique aerial photographs taken around Tioman Island during the preparation of an integrated shoreline management plan (ISMP) showed the presence of numerous, old coastal landslides that buried beaches and fringing corals as they slid into the sea. Although the slides have been re-colonized by often thick vegetation, the characteristic slide form is still recognizable on the aerial photographs. Some of these slides have influenced the evolution of the coast by providing input of materials and rocks for beach formation, or even dividing a former bay into two discrete smaller bays. In places, the clayey materials of the slide that ended in the sea have been colonized by mangroves. The presence of these old slides has great implications on attempts to develop the narrow coastal strip of land on the hilly island for tourism. The hazards posed by possible landslides must be taken into account when drawing up an ISMP for Tioman. It is important that the landslides be mapped comprehensively, studied and potential sites of slope failure be identified. The study mapped the coastal landslides from oblique aerial photographs, describes their characteristics and examines the influence of past landslide occurrences in choosing development or no development strategy for management units (MUs). The possible impacts of future slides on existing settlements, resorts and proposed development for tourism are also examined. Although in Malaysia there are laws requiring environmental impact assessments for development of large coastal resorts in which site suitability is assessed for risks, smaller resorts are exempted. Such small resorts are being built on sites that can be considered as landslide-sensitive. Such sites should be declared ‘no development zone’ to avoid future loss of property and lives. It will also be helpful to use remote sensing techniques to generate slope maps and combine slope classes with the various layers of paleoslide location, geology, rock outcrops, elevation, land use and vegetation types in a GIS platform to locate sites of possible future slope failures.

© 2012 by Geotechnical Society of Singapore (GeoSS)