Quantification of the Coastal Exposure Index (CEI) in the Kangean Islands using GIS Based Modelling
Herlambang Aulia Rachman- Zainul Hidayah- Abd Rahman As-syakur

Marine Science Department, University of Trunojoyo Madura

Marine Science Department, Udayana University

Abstract

Climate change has become an important issue in recent years, especially in the context of threats to small islands. This phenomenon causes a rise in sea level and surface temperatures that endanger coastal ecosystems. Therefore, studies related to the calculation of coastal exposure levels are very important in an effort to mitigate and reduce these impacts. In this study, the calculation of Coastal Exposure Index (CEI) was carried out on the entire coastal area of the Kangean Islands, both large and small islands. We quantified the CEI using Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) Modeling. Parameters used in this analysis include coastal topography, bathymetry, waves, surges, natural habitats (mangrove, coral, and seagrass), geomorphology, and sea level rise. The results of the analysis were then classified into categories using 25% percentile as low, moderate, high, and critical vulnerability. The results show that about 7.29% (43 km) of the coastline has a critical vulnerability level, 28.42% is categorized as high (168 km), and about 290.65 km or 48.89%, is a moderate category. Locations with critical and high vulnerability dominate the northern part of Kangean Island. This area is more exposed to the open ocean and has relatively low natural habitat cover. While the southern part of the island is dominated by mangrove cover, which is protected from exposure in the open ocean area. This condition is probably causing this area to dominantly have low and moderate CEI categories. In the Sepanjang Island area, areas with coral reef and seagrass cover have a lower CEI. The existence of natural habitats is one of the important components of coastal area exposure and reduces the level of vulnerability. The results of this study can be used as a reference in the Kangean Islands management programme as a response to climate change disasters.

Keywords: Climate Change- Coastal Exposure Index (CEI)- GIS Modelling- Kangean Island-

Topic: Marine Hazard, and Coastal Protection