Constantin Buta
DOI: 10.2478/ouacsce-2025-0020
Pages 187-201
Abstract – This paper presents a methodology for the delineation of flood-prone areas in the Topolog watershed (southeastern Romania) using GIS and hydraulic modelling software, specifically HEC-RAS and the HEC-GeoRAS extension for ArcGIS. Digital Elevation Models (DEM) derived from SRTM and ASTER GDEM satellite data were used to determine morphometric basin parameters and to construct the Triangular Irregular Network (TIN) required as the geometric input for hydraulic analysis. The peak discharge with 1% exceedance probability was estimated at approximately 338 m³/s using the rational reduction formula. Three flood scenarios at exceedance probabilities of 0.1%, 1%, and 10% were run under steady-flow conditions. The resulting floodplain boundaries were mapped in ArcGIS, providing spatial data for flood hazard assessment in compliance with EU Directive 2007/60/EC.
Keywords – ArcGIS, DEM, floodplain delineation, HEC-GeoRAS, HEC-RAS, watershed.
