Stormwater management by nature-based techniques in "La Mandria" Park. Proposals and outcomes.

This thesis investigates natural-based stormwater management in Parco La Mandria, focusing on mitigating the impact of recurring flood events, notably in 1994 and 2000, which were exacerbated by the Stura Di Lanzo and Ceronda rivers. The research adopts a comprehensive mixed-methods approach, integrating observational techniques, secondary data analysis, and Geographic Information System (GIS) mapping. Data were sourced from municipal records, a project conducted by a private company, and geoportal maps to ensure a robust and multi-faceted analysis. Furthermore, the evaluation of the sewer system's capacity was conducted using precipitation data, specifically Design Rainfall (DR) and Recorded Rainfall (RR). This assessment was crucial for creating efficient water pathways from the sewer system. Additionally, this effort aligns with the incorporation of the United Nations Sustainable Development Goals (SDGs). Three specific areas within the identified flood-risk zones, as determined by flood-risk maps from GEOPORTALE, were selected for detailed study. These areas were chosen based on their varying land uses and their susceptibility to flooding, providing a diverse set of conditions to test the effectiveness of different stormwater management strategies. The study evaluated three distinct scenarios: the existing natural and current conditions, the application of Low Impact Development (LID) controls, and an optimized version of the LID scenario, which was refined based on financial feasibility and practical implementation considerations. The primary objective was to increase permeable surfaces, thereby enhancing the area's capacity to absorb and infiltrate stormwater, and ultimately reducing surface runoff and mitigating flood risks. Results from the study indicated a significant improvement in stormwater infiltration and a corresponding reduction in runoff across the selected areas. In the industrial area, the implementation of LID controls led to an increase in infiltration by 46.89 mm, with a total runoff measured at 63.85 mm. The Fiat testing road area exhibited exceptional performance of LID controls, with infiltration rates surpassing runoff rates, recording 86.89 mm of infiltration compared to 36.14 mm of runoff. Conversely, the residential area faced limitations due to existing land use and restrictions imposed by private property, resulting in a more modest increase in infiltration (34.85 mm) and higher runoff (107.64 mm). These findings underscore the significant potential of natural-based solutions for effective flood risk mitigation. They highlight the necessity for tailored approaches that consider the specific land use and contextual constraints of each area. The study emphasizes the importance of integrating financial and functional considerations into the design and implementation of stormwater management strategies to enhance urban resilience and sustainably manage stormwater in flood-prone regions. Keywords: stormwater management model, Low impact development, natural-based solution, flood risk mitigation, Sustainable Development Goals, geography information system, permeable surfaces.