Investigation of hydraulic simulation software function in the evolution of flood plains. Apply to a study area located at Thessaly

The 2007/60/EC Directive implementation by European Member States requires flood hazard and flood risk maps for low, medium (likely return period ≥100 years) and high flood probability. In this context, hydraulic models can be used to simulate flood events and map the resulting flooded areas. Particularly in this study, three models are used: 1D HEC-RAS and quasi-2D LISFLOOD-FP and FLO-2D. These are investigated in terms of input discharge, transverse and longitudinal topographic slope, roughness coefficient and model cell size. They are also compared to each other, based on applications using simplified topographies and scenarios and so leading to conclusions about their particularities and performance. Moreover, they are applied to a study area located at Thessaly, in central Greece that is extended to a length of 40 km, from the Ali Efenti (upstream) to Amygdalia (downstream) locations at the western basin of Penios river. The area of the basin is over 6300 km2, with an average annual rainfall of 779 mm. All three models are calibrated based on a recorded Landsat image flood event, on 28/1/2003. The overall flood event occurred on 21st and 28th January 2003. The calibration parameters are the river and floodplain Manning’s coefficients as well as the river discharge.