Preliminary Assessment of Flood Hazard Reduction Strategies: The Enza River

This paper presents a preliminary hydraulic assessment of different strategies to reduce the residual flood hazard, by means of two-dimensional numerical modelling, for the case study of the Enza River (Italy). The first approach concerns the possibility of relocating the levees and lowering the floodplain at critical locations with the purpose of making “room for the river”. Numerical results are encouraging, suggesting that more in-depth analyses of technical and economic feasibility could be carried out. Additional simulations are dedicated to finding suitable locations for controlled overflows, leading to the flooding of rural areas in case of emergency. Finally, inundation scenarios due to hypothetical levee breaches are also simulated, and results can be useful to support emergency planning. Thanks to the adoption of a GPU-accelerated shallow water code, simulations of several scenarios concerning flood events with high return period could be performed using a fine spatial resolution. Although the outcomes are site-specific, the study underlines the importance of considering different structural and non-structural measures for flood management and of exploiting state-of-the-art numerical tools to identify and assess the effectiveness of planned mitigation measures.