FLOOD AND INUNDATION RISK ANALYSIS DUE TO POTENTIAL LAND SUBSIDENCE ON ALLUVIAL PLAINS

Abstract

Floods are capable of causing damage to residential areas, public facilities, and other infrastructure buildings. Areas with land use planning and land cover development that are not integrated are susceptible to experiencing flood and inundation problems. This is because regional development and spatial planning for public facilities do not consider the watershed storage capacity, leading to the inability to accommodate large amounts of runoff water. In Indonesia, the infrastructural and city development of Palembang requires extensive land reclamation because the area is an alluvial plain, characterized by swamp land. During land reclamation, storage capacity is considered, causing frequent floods and inundation in certain areas. Additionally, the phenomenon of land subsidence leads to rising river and sea water levels, which affects the low capacity of a watershed, making it no longer suitable. Based on the description, this research aimed to explore the watershed storage capacity to analyze flood problems occurring due to developments in land use and degradation through remote sensing image data. The analysis was carried out to evaluate changes in land cover (2014-2024) and the influence of land subsidence on reducing storage capacity in watershed areas to develop a flood control scenario. In this research, 2D modeling of flood events was performed to represent different land subsidence scenarios in 2014 and 2024. To determine flood area and variations in water depth, 2D HEC-RAS modeling was used to simulate flood inundation in the watershed area.