In recent decades, natural hazards have caused major disasters in natural and man-made environments. Floods are one of the most devasting natural hazards, with high levels of mortality, destruction of infrastructure, and large financial losses. This study presents a methodological approach for flood risk management at lakes and adjacent areas that is based on the implementation of the EU Floods Directive (2007/60/EC) in Greece. Contemporary engineering approaches have been used for the estimation of the inflow hydrographs. The hydraulic–hydrodynamic simulations were implemented in the following order: (a) hydrologic modeling of lake tributaries and estimation flood flow inflow to the lake, (b) flood inundation modeling of lake tributaries, (c) simulation of the lake as a closed system, (d) simulation of the lake outflows to the adjacent areas, and (e) simulation of flood inundation of rural and urban areas adjacent to the lake. The hydrologic modeling was performed using the HEC-HMS model, and the hydraulic-hydrodynamic simulations were implemented with the use of the two-dimensional HEC-RAS model. The simulations were applied to three soil moisture conditions (dry, medium and wet) and three return periods (T = 50, T = 100 and T = 1000 years) and a methodology was followed for the flood inundation modeling in urban areas. Upper and lower estimates on water depths, flow velocities and inundation areas are estimated for all inflow hydrographs and for varying roughness coefficient values. The proposed methodology presents the necessary steps and the results for the assessment of flood risk management and mapping for lake and adjacent urban and rural areas. The methodology was applied to Lake Pamvotida in Epirus, Greece, Ioannina.
Towards a better understanding of the evolution of the flood risk in Mediterranean urban areas: the case of Barcelona