An Analysis of Potential Hazard and Risk for Flood and Landslide (Case Study in West Java Province)

Abstract

Trend disaster in Indonesia has increased from year to year. Hydro-meteorological disasters such as floods, droughts, landslides, cyclones and tidal waves are the dominant type of disaster in Indonesia. Hydrometeorological disasters occurred on average almost 70% of total disaster in Indonesia. West Java Province is one of the areas that have a high potential for the occurrence of landslides. This is due to the topography of the hilly and mountainous regions, as well high population density which puts pressure on the ecosystem. The purpose of this study is to establish the methodology in determining the criteria forming floods and landslides, determine the distribution of the occurrence of potentially vulnerable hazard areas and risk of floods and landslides, as well as determine the suitability of spatial pattern in the spatial plan of West Java Province Year 2010-2030 against potential floods and landslides hazard in the province of West Java. Floods and landslides potential hazard models were constructed through spatial analysis (overlay) with scoring and weighting system of the 7 parameters used, namely: land use, rainfall, slope, elevation, landform, soil type and geology. The model risk of floods and landslides were constructed by integrating the hazard map with the analysis of vulnerability, which consists of the parameters road/ accessibility, infrastructure and land use, as well as the analysis of the element of risk, which consists of a number of density parameters population (people/km2), GDP, land use, and emergency preparedness or response. The results showed that the area of West Java which has the potential flood-prone high is 460.204 ha (12,5%) and very high is 507.274 ha (13,8%), with distribution locations in Bekasi, Cirebon, Indramayu, Karawang, Majalengka, Subang, Bandung City, Banjar City, Bekasi City, Bogor City, Cirebon City and Depok City. The area with the potential of landslide-prone high is 141.855 ha (3,9%) and very high is 14.895 ha (0,4%), with distribution locations in Bandung dan Garut. The results of field validation and data recapitulation incidence of floods and landslides in the field with BNPB data (2010-2012), show that the accuracy of a map resulting from the analysis of potential hazard and risk of flooding and landslides are quite high. The frequency of floods in the field occurs 88 times as much as the class of potential flood hazard areas of moderate to very high with a total of 115 times the incidence of flooding, or by 76.5% of the total flood. While the frequency of landslides in the field occurs 86 times in the classes as potential landslide hazard moderate to very high with a total of 113 times the incidence of landslides, or 76.1% of the total landslide. There are only 5 spatial pattern with the high suitability of the potential flood-prone high: LNH-Tsunami Hazard (97,6 %), KB-Forest (77,7 %), Municipality (90,3 %), Paddy Field (96,5 %), and KB-Water Body (76,7 %). And only 2 spatial pattern with the high suitability of the potential landslide-prone high: Conservation Forest (86,8 %) and Primary Forest (80,2 %).