The Pakke River is a mountainous stream that flows through the Pakke Kesang district of Arunachal Pradesh, India, and is a tributary of the mighty Brahmaputra River. During the monsoon season, it transports a large amount of silt and sediment. In this region, flash floods are a general water-related natural disaster that resulted in massive loss of property and life. In addition, the raising of the riverbed due to the deposition of gravel, sand, and other debris in the upstream portion of the main channel caused overflooding and meandering of the river. This meandering of the Pakke River towards the left bank has flooded and damaged agricultural land, rural settlement, and nearby areas of the Siejosa town. HEC-RAS 6.3 is used to simulate one-dimensional hydrodynamic flood modeling in order to simulate water surface elevations and velocities for return periods of 25 years, 50 years, and 100 years. In this simulation, Gumbel's extreme value distribution method has been adopted by applying the available maximum annual discharge data for the past 26 years (1995-2020) collected from the water resources department, Government of Arunachal Pradesh. Identification of the most vulnerable areas by generating flood inundation maps of the study location is also one of the objectives of this study. This study will be useful in determining appropriate preventive and mitigation measures in the region. Being situated in a remote location there are hardly any studies available of this kind for this river.
