Two-Phase Fuzzy System for Multiple Hydro-Meteorological Spatial Risk Mapping in Surabaya, Indonesia

Abstract

Disaster in Indonesia is caused by hydro-meteorological factors dominate disasters in Indonesia every year. Surabaya is the capital of East Java, which has population growth problems and a high incidence of hydro-meteorological disasters. Surabaya has a high vulnerability to floods, drought, and strong winds. The mapping of the risk of hydrometeorological hazards in cities with rapidly growing populations is used as a guide for preventive measures. The map can provide information on disaster risk which consists of 3 aspects, they are a hazard, vulnerability, and capacity. A multi-disaster map is needed because it provides a complete picture of the potential and history of disasters in an area. The hydro-meteorological multi-disaster map can be used by policymakers to weigh benefits or risks and to resolve contingent disasters. In this study, we proposed a multiple hydro-meteorological spatial risk mapping in Surabaya city using a two-phase Fuzzy system. The first phase assesses the risk of each flood, drought, and wind disaster in each sub-district based on multi-criteria, such as hazard, vulnerability, and capacity. The second phase calculates the risk assessment of the three disasters and divides it into three levels of risk, consist of the low, medium, and high for each sub-district. In 2014 and 2015, there are 16.1% of low risk, 77.4% of medium risk, and 6.5% high risk sub-districts for multiple hydro-meteorological risk assessments. The results of the analysis show that there are three districts in the city of Surabaya that are at high risk of hydro-meteorological disasters, consisting of Tambaksari, Wonokromo, and Sawahan.