Inventory of River Basin Flood Events for Drainage System Examination Using Multi-Temporal Composite Remote Sensing Data

- Palembang City is divided into two regions by the Musi river, and there are 114 tributaries streamed within Palembang City, with 31.58% located in the Seberang Ilir region and 68.42% in the Seberang Ulu region. In the lowland topography of Palembang City, with most of the region below 5 m above mean sea level, flooding becomes repetitive. This paper examines the flooded area within the Bendung river basin using multi-temporal composite remote sensing radar data from Sentinel 1. Flood events in November 2018 and December 2021 were selected. The flood extent and affected populations will be calculated using Information System (GIS) application. In this study, flood extent was delineated and compared for different digital elevation models. It is found that the threshold value, the DEM, and the availability of radar data in conjunction with the flood event will better delineate the affected area to the flood. The DEM contributed a 37.5% to 83% difference in the delineated area calculation. The script in the GEE is customizable for different areas of interest and can be applied to different areas with adjustments to the threshold value that should be a minimum of 1.0 or higher.