Hydrological and hydraulic modelling for a severe flood event in Sperchios River Basin

A combined hydrological and hydraulic analysis is presented for an extreme flood event occurred on February 6, 2012 in Sperchios River Basin, located in Central Greece. This event caused the river’s overflow and, consequently, several damages to infrastructure and agricultural land. Sperchios River Basin is a case of ungauged basin and only rainfall measurements of fine temporal scale are available. The hydrological analysis was performed with the aid of the Hydrologic Modeling System (HEC-HMS) to incorporate and combine different methods concerning the rainfall-runoff transformation, the hydrological losses, the river routing and the baseflow recession, and finally to generate the flood hydrograph. The hydrological analysis output was then used in the River Analysis System (HEC-RAS), which has the ability to model unsteady flow through a river channel network and produces the water profiles, velocity and inundation maps of the flood plain. The implementation of this integrated model for historic flood events in such ungauged basins is useful for reducing the uncertainty and developing robust flood forecasting and early warning systems in order to reduce life casualties and mitigate losses due to flooding.