Development of flood hazard model based on land use and land cover change 1973–2023 in Cikapundung watershed, West Java Province

Abstract

Changes in LULC, caused by urbanization and deforestation, can disrupt ecosystem patterns, including climate change. These changes lead to a decrease in the infiltration capacity of the soil, thereby increasing the surface runoff. Understanding LULC change over long periods and impacts is important for mitigating flood risks. This study analyzes LULC changes in the Cikapundung watershed over a 50-year period (1973–2023) and models flood inundation for 2014 and 2023, predict for 2032, which highlight critical knowledge gap this study addresses. The LULC model was conducted using satellite imagery, classified using random forest algorithm. The result shows the study area experienced significant changes, with built-up expanded by about 700% while non-agricultural vegetation declining by around 50%. The LULC model is considered along with DEM and the 2 to 100-year return periods to model the flood inundation, which was processed in HEC-RAS. The flood inundation model shows minimal variation between 2014–2032, with rainfall return period intensity having a greater influence on flood inundations, evidenced by increasing inundation corresponding to longer return intervals. The study is anticipated to inform spatial planning and disaster risk management decisions, as well as aid in adapting to the increasingly apparent effects of climate change.