Coastal flood risk assessment and coastal zone management

Abstract

The rise of sea level increases the risk of coastal flooding by increasing the probability of occurrence of flood event at a given height. The essence of coastal planning and management in the future relies on an accurate coastal flood risk assessment with regards to sea level rise. Through the set up of flood risk assessment model in Geographic Information System (GIS) using Shuttle Radar Topography Mission (SRTM) elevation data, flood height data, and sea level rise estimate based on IPCC high emission scenario, areas at risk of inundation at Seberang Perai (highly developed area) and Kuantan-Pekan (less developed area) in Malaysia were identified. Flood maps were produced subsequently. Damage costs associated with a given flood event were calculated through the identification land value of different land use categories. Four flood management tools had been utlisied in the study. They include “Do nothing”, “Flood insurance”, “No development” and “Hold the line”. The costeffectiveness of these flood management tools was evaluated over a course of 200-year based on a 1 in 200-year flood event for both study locations. Results from the study show that the effectiveness of flood management tools varies with location and land use pattern. However, in both locations, “Flood insurance” is concluded to be the most economically viable option for coastal zone management in Malaysia in the future as the damage cost incurred from a flood event is effectively reduced via the implementation of “Flood insurance” policy. Flood insurance is currently not a common practice in Malaysia. However, in order to reduce the uncertaities resulted from flood risk assessment, the study recommends more accurate elevation data to be captured for future analysis. Besides, it is also recognised that there is a need for Malaysia to maintain long term measurement of sea level.