Ricerc@Sapienza

The proposed research can significantly contribute to improve flood resilience of Mediterranean compact cities, which are an important part of the European built heritage. These urban contexts are suffering increasing vulnerability to flooding due to the lack of an organic framework to mitigate connected risks. Indeed, the prevention and the management of such hazards have always been carried out with defensive actions and traditional engineering solutions, disregarding the essential role of other connected disciplines. The necessity to go beyond this approach has been recognized only in recent years in view of the fact that urban flood risk mitigation is a complex issue that involves different actors (inhabitants, developers, local authorities, designers) and several interrelated intervention scales.
The innovative feature of the proposed research relies in its cross-scale, interdisciplinary approach, which aims to answer this need in a coordinated way, integrating architectural, geological and hydrology professionals in order to find proper site-specific solutions. Thanks to the different cultural background of the partners involved in the research group, it will be possible to develop a procedure to analyze all those components of the Mediterranean compact city that contribute to urban behavior during flood and to check the effectiveness and the feasibility of urban and architectural interventions designed to make it more resilient.
The importance of this goal is connected to the fact that many researches about flood mitigation strategies refer to contexts that are very different from the area of interest of the proposed work, in terms of climate and urban features. Mediterranean compact cities, in fact, are characterized by a peculiar climate with a specific annual rainfall regime and studies evaluating the effectiveness of practices that were specifically developed for colder regions, such as green roofs, are still scarce [1]. Moreover, Mediterranean cities have a particular relationship between public outdoor areas and buildings, which form dense and compact textures. Furthermore, the majority of building stock is dated and, to a great extent, it has been constructed with massive building techniques. Finally, parts of the existing urban developments are informal settlements that do not respect town planning regulations. Solutions to flooding risks are usually applied either at the urban scale or at the building scale, while an interconnection is needed to evaluate them with a cross-scale approach: single measures such as permeable paving or green roofs have been widely studied but the cross-scale approach would permit to add to these researches a more complete overview on solution effectiveness.
There are also other general gaps in current knowledge related to urban flood resilience that need to be addressed, to the best of Proponents' knowledge. Firstly, few studies have evaluated the effects of Sustainable Urban Drainage Systems (SUDS) on urban drainage systems performance [2]. In particular, there is a limited number of studies investigating the effect of pervious pavements on the different components of the urban ecosystem, including soil [3], and there are still many barriers to the implementation of biodiversity-led green infrastructure in urban areas, connected to cost/benefit assessment, maintenance issues and applicable policy [4]. Moreover, in Italy there are no examples of floating and amphibious architecture built with innovative technologies and, as for the hydrology perspective, the linked vertical risk delocalization strategies are still poorly studied: in fact, modelling tools that simulate the response of this building typologies to flooding events are scarcely applied. Finally, few studies of the above-mentioned discipline have applied two-dimensional fluid-dynamics models to specific sites or have attempted to refine the meshes currently used in Flood Inundation Models to simulate more accurately the response of smaller areas.
The proposed research aims at addressing these gaps: the outcomes are intended to be useful tools for designers and local authorities to respond to site-specific flooding challenges. The findings would be applied to the selected case studies towards an in depth understanding of their response to flood events and the definition of feasible solutions with additional co-benefits. The cross-scale interdisciplinary approach of the research would definitely improve the effectiveness of existing protection strategies and would have positive benefits for inhabitants.
[1] Fioretti R. et al. Green roof energy and water related performance (...) Build.and Env.45.8(2010): 1890-1904
[2] Pappalardo V. et al. The potential of green infrastructure application (...) Ecosystem Services (2017)
[3] Fini A. et al. Nature based solutions to mitigate soil sealing (...) Env.Research 156 (2017): 443-454
[4] Connop S. et al. Renaturing cities (...) Env.Science&Policy 62 (2016): 99-111