Flood impact assessment using earth observation data and geospatial technique: A case study from Bojonegoro Regency, Indonesia

Abstract Floods are the primary natural hazard in Indonesia, accounting for 43% of all recorded incidents, and are particularly prominent in the Bjonegoro Regency. Satellite observations, notably facilitated by platforms such as Google Earth Engine (GEE), are indispensable for flood studies, furnishing crucial spatial and temporal data. This study aims to conduct a flood impact assessment using earth observation data to assess its impact on cropland area. To analyze flood extent map, we utilized a change detection method with the Sentinel-1 GRD product. This approach allows for an effective comparison of data collected before and after the flood event. By applying an overlay technique between the flood extent map and land use/land cover (LULC), we can assess the impact of the flood on cropland areas. The flood extent map showed that 13% of the region was inundated. 14028 hectares — 15 % of cropland land—were damaged. Urban areas were less damaged but had significant socio-economic effects, affecting 200 hectares. Despite modest damage to tree cover (2% of the total area), flood control and forest protection remain crucial. Flooding affected 3 % of the population, or 42056 people, stressing the need for disaster management and community resilience. The diverse impacts of LULC categories highlight the need for targeted flood risk management strategies that integrate infrastructure improvements, land use planning, early warning systems, and community engagement to protect livelihoods and support sustainable development in flood-prone regions.