Adapting drainage networks to the urban development: An assessment of different integrated approach alternatives for a sustainable flood risk mitigation in Northern Italy

Political bodies, planners and the scientific community agree on the need for making cities and communities resilient and sustainable in the near future. Urban infrastructures generate too often negative impacts on the surrounding environment. Hence, it is considered today an absolute priority implementing actions able to generate an optimal relationship between citizens and the environment. Even in the field of hydraulic constructions and urban hydrology, it is therefore essential to develop water management strategies able to contribute to the definition of this new paradigm of city. With regard to flood management, integrated strategies including the combined implementation of Stormwater Detention Tanks and Sustainable Drainage Strategies (SuDS) seem successful solutions but additional studies are required to define their potential. This research aims at assessing and comparing different integrated drainage alternatives involving the single or combined implementation of two categories of SuDS in Sesto Ulteriano (Northern Italy): Green Infrastructures (GI) and flood control areas. The Hydraulic Risk Mitigation Index (HRMI), is here proposed to account for different hydraulic parameters in the performance assessment of an integrated drainage strategy. Results highlighted the importance of HRMI as decision support measure and the effectiveness of SuDS strategies, especially those involving GI, at reducing urban flooding.