Flood characteristics analyses in the Jratunseluna river basin due to the impact of Kedungsepur national strategic area development

Abstract

The area of the Jratunseluna river basin is categorized as a high-risk flood vulnerability. The urban development plan can worsen this condition through Kedungsepur national strategic area. The objective of this study is to identify flood characteristics in Jratunseluna river basin caused by the alteration of land use due to Kedungsepur national strategic area development through rainfall-runoff 2D simulation. The RRI 2D model was chosen because it could simulate flood inundation comprehensively in all river systems while the other models such as HEC-HMS, TOPMODEL, and Tank models have a limitation on it. The input data used for the RRI model were rainfall data, topography (DEM), and land use maps. The rain data used in the simulation was the Global Precipitation Measurement (GPM) from 2010 to 2020. The study results indicate that the flood risk level would increase during the implementation of the Kedungsepur national strategic area development. The flood duration and peak discharge increase mainly characterize the increase in flood risk. The most significant increase in peak discharge among the four outlets is obtained in the Garang watershed. In the case of a 2-year flood, the peak discharge increased by 44.91% from 262.18 m3/s to 379.92 m3/s and for the case of a 50-year flood, the peak discharge increased by 54.34% from 331.63 m3/s to 511.83 m3/.