2D Hydrodinamic Modelling of Flood Inundation Scenarios of Krueng Peuto River at North Aceh Regency of Aceh Province

Abstract

Krueng Peuto sub-watershed, is a part of the Krueng Keureuto watershed in North Aceh that frequently experiences flooding. At the end of 2021, an embankment broke on the Peuto River and caused river overflow and submerged hundreds of houses in 33 villages around the sub-watershed. This study aims to analyze the critical circumstance of the Krueng Peuto sub-watershed which potentially lead to Peuto River overflow, using a 2D hydrodynamic model Geo-HECRAS. The validation of flood distribution points is based on historical floods conditions, i.e. depth and area of flood inundation, with modeling results for return periods scenarios of 2, 5, 10, 25, 50, and 100 years. From the modelling results, the flood inundation area at the 25-year return period was 25.514 km2, with a flood depth of 0-1 m covering an area of 8.35 km2 (32.73%), a depth of 1-2 m covering an area of 6.71 km2 (26.33%), and a depth of >2 m covering an area of 10.44 km2 (40.95%). The validation results of the 25-year return period flood inundation with flood distribution points show that in the flood inundation area there are 17 flood distribution points or the flood inundation area already represents 81% of flood distribution points.