Hydrodynamic Numerical Simulation and Flood Risk Assessment in a Natural River

Evangelia Farsirotou, Athanasios Blantas

The current research work presents one-dimensional numerical simulation results of water surface elevation along a natural river, in order to investigate an accurate operation of three existing dams, with flat and arched gates, for flood protection. The study reports an extensive numerical simulation procedure of four different operations of the dam gates, including all gates opened, all gates closed, only flat gates opened and only arched gates opened, for flood risk estimation through the studied river reach. The one-dimensional hydrodynamic numerical simulation procedure of water surface profile variation, under steady flow conditions, through the natural river, was performed for available maximum inflow discharges of 5, 25 and 100 year flood period.

All numerical results are graphically presented and comparisons between different gate operations provide an accurate investigation of a safe dam handling in order to prevent the surrounding river area against flood events. The applied hydrodynamic numerical model, “HEC-RAS” model, is a useful and accurate methodology for flood risk assessment in a natural river area, with complicate geometries and different hydraulic constructions.