Flood Hazard Mapping in Cimandiri Watershed using Fuzzy Logic Method Based on Multi-Source Geospatial Datasets

Abstract Flood is a frequent disaster in the Cimandiri watershed. This is evidenced by the fact that during 2017-2022, 37 floods occurred in this area. This condition causes losses to the community and damage to the environmental ecosystem. Therefore, disaster management is needed to overcome and reduce the impact of this flood. One management that can be done is by mapping flood hazard areas. However, until now there is no map available that presents the flood hazard study area in the Cimandiri watershed. If available, the maps generally cover Regency, sub-Regency, or large-scale maps covering the entire territory of Indonesia. This condition causes deficiencies or misinformation on the map because the scale of the study is irrelevant. Based on this, this study attempts to conduct flood hazard mapping in the Cimandiri watershed with a scale of analysis of 100,000. This study uses fuzzy logic method to generate hazard maps based on spatial parameters, rainfall, distance from the river, elevation, slope, vegetation density, land cover, soil type, and topographic wetness. The results of this method produce a hazard map with a class range of 0 to 1, a class that is close to 1 means that it has a high level of hazard. To see the correctness of this map, a validation test was carried out using flood data from 2017-2022 which contained 37 flood event data. Based on the validation results, 86% of flood points are in the non-0 hazard class (low hazard), only 13% are incorrect because they are in the 0-hazard class.