Identification of hotspots of flood risk in High Mountain Asia region based on geomorphology and climate data

<p>High Mountain Asia (HMA) has the most complex terrain with active hydrologic and geomorphologic processes. Climate change has expedited glacial melt and altered monsoon rain intensity. This has increased flood vulnerability across the region. There have been a few initiatives to measure the vulnerability locally. However, to identify hotspots of flood risk across the region, investigation of the entire HMA region is necessary. Unfortunately, in ungauged basins, the use of traditional floodplain mapping techniques is prevented by the lack of the extensive data required. The present work aims to provide a remote sensing-based flood-risk assessment model that maps and quantifies susceptibility in flood-prone areas. We developed a procedure for floodplain delineation based on high-resolution terrain data and a geomorphic classifier, coupled with satellite-derived extreme rainfall quantiles, and records of past flood events. For this work, we used the unique 8-meter Digital Elevation Models (DEMs) for HMA that are available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). The geomorphic classifier is based on the Hydraulic Scaling Function automatically derived from the DEM, which is used to normalize topography according to the ratio between the local elevations along the drainage network and the riverbanks.  We assess the flood risk hot spots for a specific year based on the spatial distribution of flood losses, drainage density, flood-prone areas, and rainfall. This local flood-risk assessment framework, gradually applied across the entire HMA domain, will increase the awareness of flood risk, towards improved measures for flood risk reduction.</p>

DELINEATION OF FLOOD PLAIN EXTENSION

Floodplain delineation is an effective approach in either avoiding of water crisis or making pragmatic decisions in terms of water management strategies. In this study a flood plain extension has been developed in ArcGIS and HE-CRAS models and a comparison has been made within three different scenarios of discharge. The results showed in low and medium discharge scenarios the buffer zone acts as a safety factor zone to adjacent infrastructure either agricultural or residential, but in high discharge condition buffer zone is entirely filled with stream water hence yet more safety regulation should be considered in order to avoid human and resource loss or damage within adjacent areas. Keywords: Flood plain delineation, Water depth profile, HE-CRAS, F. Sakhaee. Parks College of Engineering, Aviation and Technology, Civil Engineering Dept., Saint Louis University, USA

Floodplain Delineation Based on Analysis of Digital Elevation Model, Soil Maps and Occurrence of Quaternary Formations

This paper presents a GIS based method of indicating flood extent in a mountainous river basin. Only main river with the valley is object of this analysis. The approach used in this work combines analysis of digital elevation model (DEM) obtained from LIDAR data with presence of alluvial soils and quaternary formations. In addition, in this article an attempt of calculating flood wave height for delineated floodplain is presented. The results are compared with floodplains derived from one of the products of country-scale project „IT system for protection against extraordinary hazards” (ISOK) which are flood hazard maps and with the extent of The Great Flood of 1997. Indication of the area flooded during Poland’s Great Flood in July 1997 is based on the hydrological data from Institute of Meteorology and Water Management – National Research Institute (IMGW – PIB).