The assessment for selection and correction of <scp>RS</scp> ‐based <scp>DEMs</scp> and <scp>1D</scp> and <scp>2D HEC‐RAS</scp> models for flood mapping in different river types

Digital Elevation Models (DEMs) act as an essential input to hydraulic models for the simulation of flood hazard maps. Coarser resolution DEMs are subject higher levels uncertainty, particularly in capturing river-bed bathymetry. The principal aim present study was assess potential use freely available and 1D 2D HEC-RAS modeling approaches mapping four different types river morphology. DEM created from direct survey (Surveyed DEM) used a benchmark three remote sensing-based (i.e., ALOS, SRTM, ASTER). results indicated that ALOS is more accurate. However, regeneration main-channel bathymetry poor floodplain-meandering braided reaches. were then corrected by optimizing number layout representative sections. A total 144 tests carried out. flood-mapping index F increased 86% 91%. with model sufficient straight reaches (F-index 84%). In rivers, had be reach F-index up 81%. responses both almost identical case wide-braided rivers.