Avoided Surface Runoff as an Ecosystem Service: the Case Study of a Green Area in Turin (IT)

The following work is part of the broader panorama of the relationship between man and nature, with a point of view looking to the future: the study of ecosystem services provided by nature and, in particular, by vegetation, is taking on a role gradually more and more consistent, in relation to the need of climate change adaptation. And what better representation of the human footprint than city: the urban scale is deepened in this project, through an investigation aimed at quantifying a specific ecosystem service: the avoided surface runoff. The reference area is a park of about 35 hectares located in the suburbs of Turin city, inserted within the relative metropolitan area: the tool used is a specific software suite for quantifying the ecosystem services provided by vegetation. In particular, the evaluation of the avoided surface runoff was carried out relying on two different i-Tree programs: using the Eco tool, aimed at studying the environmental benefits produced by an urban forest, the focus was on the quantity of water that trees are able to subtract, through interception, from the water runoff that has the city sewers as its final destination, while i-Tree Hydro, a hydrological model specific for vegetation, allowed to quantify the total amount of surface runoff interesting the green area, taking into account the whole vegetative sector. Linking the final results of both i-Tree programs, the study aims to discuss the role of the park in the water management of the sewerage system and, at the same time, make a reflection on the relationship between urban green spaces within built-up areas and the reduction of hydrogeological risk