A Study Conducted in Labaro - Prima Porta District, Rome, Italy
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Environmental Engineering and Management Journal October 2020, Vol. 19, No. 10, 1835-1846 http://www.eemj.icpm.tuiasi.ro/; http://www.eemj.eu “Gheorghe Asachi” Technical University of Iasi, Romania NATURE-BASED SOLUTIONS FOR FLOOD MANAGEMENT: A STUDY CONDUCTED IN LABARO - PRIMA PORTA DISTRICT, ROME, ITALY Giulia Pandolfi1, Jessica Pettinari2 1Architecture Department - Urban studies, University of Roma Tre, Largo Giovanni Battista Marzi, N10 – 00154, Roma 2Architecture Department - Landscape, University of Rome Sapienza, Piazza Borghese, N9 - 00186 Roma Abstract ‘Labaro-Prima Porta’ is a district in the outskirts of Rome, increasingly afflicted by recurrent floods. In order to reduce the local runoff volume, this paper defines a resilience and twofold strategy. At first, the use of a hydrologic software, called Storm Water Management Model (SWMM), along the research makes possible the evaluation of which Nature-based Solutions (NbS) are more effective in terms of runoff management. The results demonstrate short-term positive effects, with an immediate reduction of the local discharge of about 8%. The second phase of the study explores the possibility of designing a resilient ‘Labaro-Prima Porta’ district. A master plan, structured in two overlapping scales, is proposed. One large-scale, improving the ecological network of the Veio Park and the rivers close to the urban settlements; in the second layer a green blue infrastructure at the district scale is defined, including a 3.3 km greenway as an urban and ecological corridor. The overall objective of this study is to provide theoretical support for the “sponge city” theory. Key words: hydro-ecological infrastructure, landscape design, SWMM, nature-based solutions, sponge city, urban water management Received: February, 2020; Revised final: June, 2020; Accepted: July, 2020; Published in final edited form: October, 2020 1. Introduction landscape structure, besides not considering the social aspects at all. On the contrary, this work highlights the The growing flood risk is a major challenge importance of working following environmentally today for land and urban planning: there has never sustainable lines joining together the simulation with been a stronger incentive to re-think our approach to SMWW of the urban runoff (Rossman, 2010) and the environment and to use differently land, water and importance of urban and landscape design. The design space in our towns and cities. One of the urbanization of city roads should be adjusted timely, since it is a direct effects is the continuous growth of the very important part of urban development. It would be impervious areas, which interferes with the natural crucial to create ecological grass ditches, sunken lawn flow of the water cycle, and increases the urban runoff. areas, rain gardens and permeable pavement. Zhang et In recent years, many storm events have haunted the al. (2009) used SWMM to simulate the surface runoff cities, where in most cases the urban sewerage is no of a residential area in Nanjing which was longer correctly dimensioned due to recent extreme reconstructed with sunken lawn areas and permeable rain events. The tendency in water management of the pavement (Zhen-ci and Yuongchen, 2017) studied the current policies is to favor fast and expensive solutions relationship between rainfall and runoff in the area when the damage is already done. Italian authorities, under four different underlying surfaces conditions, in particular, have often shown little interest in where, thanks to the distributed water stability model, environmental issues, harming the territorial and the work achieves some possible suggestions to how Author to whom all correspondence should be addressed: e-mail: [email protected] Pandolfi and Pettinari/Environmental Engineering and Management Journal 19 (2020), 10, 1835-1846 to contribute scientific to the creation of an ecological each other to solve problems from different scales and city. Other studies analyzed the effect of different maximize environmental, economic, and social kinds of Nature-based Solutions (NbS) on the control benefits” (Liang and Hou, 2018). of surface runoff, such as the beneficial hydraulic The paper focuses on Labaro-Prima Porta effects of green roofs (Bliss et al., 2009; Gregoire and District, located in the north of Rome, as a case study Clausen, 2011; Lamera et al., 2014), rainwater storage area to assess other content to be added to Sponge City tanks (Abbott et al., 2007) and draining parking lots theory. In particular, regarding the four points (Collins et al., 2008). mentioned above, particular attention was given to In these latter 10 years the most interesting point 1, 2 and 4. research steps that kept together modeling approach, case study and landscape where carried out on chinese 2. Case study territory since the Chinese government launched the sponge city pilot construction in 2015. There is a long The study focuses on Labaro-Prima Porta, a list of case study investigated, but here we mention: district in the outskirts of Rome (Italy), increasingly Beijing, Liupanshui and Qunli National Wetland Park afflicted by recurrent floods, even if the drainage in Harbin, which define how rain-runoff control system has been recently improved (Fig.1). The effects and landscape security pattern are essential for negative impacts of rainwater in Labaro-Prima Porta sponge city theory construction (Kongjian et al., 2015; is the result of different aspects: 1) the neighborhood Xia et al. 2017). A more recent paper describes four was built during the first decades of the second aspects that a sponge city construction must have: 1) postwar period, mostly out of planning, without taking should consider and be in line with local conditions; into account adequate urbanization criteria, not only 2) in order to play a better role it should take into from an environmental point of view, but even from a account the concept of an ecological city and a smart urban one; 2) greater waterproofing of soils due to city; 3) should requires the active participation of asphalt and other similar materials does not allow the more citizens; 4) “… requires intensive natural water cycle; 3) recent effects of climate change interdisciplinary cooperation and cross-scale magnified these structural problems in Rome (Filpa research. Due to the complexity of the construction of and Ombuen, 2014) specially in some neighborhoods sponge cities, multidisciplinary cooperation is like Labaro-Prima Porta (Benelli and Camerata, required. The multi-professionals are integrated with 2014). Fig. 1. Labaro-Prima Porta, simulation of the flooded areas on the event 31 January 2014 1836 Nature-based solutions for flood management: A study conducted in Labaro - Prima Porta District, Rome, Italy To this end, the study describes a twofold network transport layer, built with SWMM, is strategy where, thanks to the use of an open-source collected from the Department of Hydraulic hydrologic software, called SWMM it is possible to Engineering of Roma Tre University, since the start an analysis about which devices, depending on Department in 2005 started working on the the amount of water stored, have greater effectiveness identification of the causes of flooding in Labaro- in the context of the project. The research explores Prima Porta district, in collaboration with Rome three different operational steps and investigates also Municipality and the Civil Protection Agency, for a possible master plan design. The study is divided which the adaptation works to the system were then into two chapters and final results. made starting from 2015 until 2018. Finally, the The first chapter describes how the ‘Urban analysis regarding the main statistics of the Hydrologic Model’ was built. In order to study the distribution of channel lengths and hill-slope for the potential of SWMM and to elaborate a new ‘Urban transport layer were carried out by (Volpi et al., 2012), Hydrologic Model’ stackable with the existing Sewer and the urban drainage system replies the method used Model created by the Department of Hydraulic for Warangal Campus (Rangari et al., 2018), but in Engineering of Roma Tre University (Calenda and general is the procedure suggested in SWMM manual Mancini, 2009; Calenda et al., 2009; DE, 2005; (Gironas et al., 2010). DSIMU, 2015), it was necessary to improve the detail on the ‘Land Area Layer’, defining more accurately: urban density, property status, type of coverage (flat or pitched) and soil permeability. To this end it was necessary to use different mapping software DEM, GIS and CAD (Jiang et al., 2010) that could provide the geometric and quantitative characteristics in a form compatible (layers) with the previous Sewer Model. The second chapter shows a possible design application on the local context. The project intends to exploit the critical aspects as a potential, utilizing the hydro-morphology of the terrain to create a sustainable water drainage system, in order to slow down the water descent into the hilly area. The project is articulated in two different strategies: 1) improvement of the ecological network of the adjoining Veio’s park to increase the urban resilience 2) create a connected green and blue infrastructure in the urban settlement. Fig. 2. Simplification of SWMM layers Finally, ‘Results and discussion’ consists in the evaluation on the ‘Urban Hydrologic Model’, at first Basically, SWMM works as shown in the on public buildings and then on private ones too, of previous figure (Fig.