Author(s): George Mitsopoulos; Apollon Bournas; Aimilia Theochari; Michalis Diakakis; Aristeidis Bloutsos; Efthymios Lekkas; Evangelos Baltas; Anastasios I. Stamou

Linked Author(s): George Mitsopoulos, Aristeidis Bloutsos, Apollon Bournas, Anastasios I. Stamou

Keywords: Nature Based Solutions; Climate Change; Flood risk; Hydrologic models; Hydrodynamic models

Abstract: Nature Based Solutions (NBS) are proposed in Agia Triada and Oinoi river basins of areas equal to 22.36 km2 and 25.22 km2, respectively, upstream of the historic town of Marathon in Attica, to reduce flood risk. These NBS include the land use change of a total bushland area of 29.51 km2 to forest land and the development of flood basins in the main streams and their floodplains of a total area equal to 11.02 ha. We applied a 4-step methodology using an integrated modelling approach in climate change conditions to determine the effects of the NBS. Calculations showed that the NBS have the following effects: (1) the peak flow rates and the flood volumes of the hydrographs are reduced by 28-26% and 17-23%, respectively, (2) the inundation areas decrease by approximately 17%, (3) the maximum water depths are reduced by 20-35% and the maximum water velocities by 18-27% in the main streets of the town of Marathon, (4) the flood hazard follows the behavior of the flow characteristics being very high near the banks of the Oinoi stream and in the main streets of the town of Marathon and (5) the average flood risk is reduced by 8% in the inundation areas and 15% in the main streets of the town of Marathon. The effect of the NBS on flood risk is maximized in the north-eastern part of the town that was inundated without the implementation of the NBS and non-inundated with the NBS.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p1768-cd

Year: 2023