On the LID systems effectiveness for urban stormwater management: Case study in Southern Italy

Here we present the hydrological effectiveness of Low Impact development (LID) solutions at urban catchment scale, by modelling a highly urbanised area located in South Italy. For the model creation and simulation, PCSWMM based on the Storm Water Management Model (SWMM) was used. The analysis was carried out by considering different land use conversion scenarios including the implementation of LID practices. Therefore, a specific permeable pavement and green roof developed and implemented at full scale at University of Calabria were chosen as source-control measures. The simulations were run by using as input a synthetic hyetograph of 30 min with return period of 10 years. Three hydrological performance indexes, Runoff Coefficient (RC), Runoff Reduction (RR) and Peak Flow Reduction (PFR) were evaluated at subcatchment scale and, a mean value was estimated for an overall evaluation. Main findings show that RR and PFR linearly increase with the reduction of imperviousness due to the modelling of a major percentage of LID solutions, while the RC decreases. In addition, first detailed results reveal the suitability of LID solutions to reduce surface runoff also for the scenario 1 which considers the conversion of only 30% of specific impervious surface in green roofs and permeable pavements.