Hydrological analysis and hydraulic simulation for Sperchios River Basin

Abstract

This research work deals with a flood risk assessment methodology for the ungauged Sperchios River basin, an area of 1003 km2 located in Central Greece. This region is frequently exposed to floods, thus a floodplain evaluation is very important in order to take measures against the effects of floods. Initially, a hydrological analysis was conducted through the Hydrologic Modeling System (HEC-HMS) using the estimation of the runoff, based on the Natural Resources Conservation Service (NRCS) method and the appropriate curve numbers (CN) for the study area. The output of the hydrological analysis was a flood hydrograph, which was then used for hydraulic simulation through the River Analysis System (HEC-RAS) (2D), having the ability to produce the water profiles, velocity and inundation maps of the floodplain. The results of this work indicated that surface runoff is equal to 66% of the total rainfall and the flood hydrograph peaks at 1969 m3/s, under normal soil moisture conditions. An increase of 22% in the surface runoff, leads to a peak of 2756 m3/s (40% increase), under wet conditions. The adopted methodology contributes to the development of robust flood forecasting and early warning systems.