INTEGRATING LIDAR DATA, 2D HEC-RAS MODELING AND REMOTE SENSING TO DEVELOP FLOOD HAZARD MAPS DOWNSTREAM OF A LARGE RESERVOIR IN THE INNER EASTERN CARPATHIANS

Abstract

The use of 1D, 2D, and 1D/2D modelling techniques to identify flood prone areas is a critical component of any flood hazard management project (e.g., APDF – action plan for dam failure) in the proximity of big dams and reservoirs. In this work, we manage to computed flood hazard models using 2D HEC-RAS module based on Digital Elevation Models (DEM’s) derived from Light Detection and Ranging (LiDAR) data and pre- and post-processed using Geographic Information Systems (GIS)-based software (e.g., ArcGIS, HEC-RAS). Therefore, to produce urban flood hazard (FH) maps downstream of the Strâmtori-Firiza reservoir (S-Fr) in NW Romania, a multi-scenario approach based on LiDAR-derived DEM integration, 2D hydraulic modeling, and remote sensing (RS) data validation is provided. In this context, to assess the flood control capacity (FCC) of the S-Fr hydro-technical system, three flood tests based on S-Fr flow rate with 5% (167 m3/s), 1% (270 m3/s) and 0.1% (447 m3/s) return periods were performed. The flood impact within the urban area of Baia Mare located downstream of S-Fr was achieved for each flood scenarios using four spatial data derived from the RAS Mapper module: flood extent (FE), flood depth (FD), flood velocity (FV) and flood hazard (FH). The results indicate that a large area of Baia Mare city can be affected by a potential flood caused by a dam failure and also contribute to the APDF update of S-Fr dam.