Tremiterra, Maria Rosa (2018) Urban Coastal Systems and Coastal Flooding. A GIS-based tool for planning climate-sensitive cities. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Lingua: English
Title: Urban Coastal Systems and Coastal Flooding. A GIS-based tool for planning climate-sensitive cities
Tremiterra, Maria
Date: December 2018
Number of Pages: 140
Institution: Università degli Studi di Napoli Federico II
Department: Ingegneria Civile, Edile e Ambientale
Dottorato: Ingegneria dei sistemi civili
Ciclo di dottorato: 31
Coordinatore del Corso di dottorato:
Gargiulo, CarmelaUNSPECIFIED
Date: December 2018
Number of Pages: 140
Uncontrolled Keywords: Cities; Coastal Flooding; GIS-based tool
Settori scientifico-disciplinari del MIUR: Area 08 - Ingegneria civile e Architettura > ICAR/20 - Tecnica e pianificazione urbanistica
Date Deposited: 07 Jan 2019 18:14
Last Modified: 30 Jun 2020 08:56


In 2013, the "EU Strategy in adaptation to climate change" adopted by the European Commission stated the need of adaptation to climate impacts of European territories, including coastal areas. In fact, these areas are characterized by a higher concentration of buildings and people in comparison to inland areas. Furthermore, economic assets within 500 meters from the coastline have a value between €500 and €1,000 billion (EEA, 2016). Due to their several resources and the high degree of accessibility, these areas are very attractive for people and, hence, their population growth is expected to increase in the future (Neumann et al., 2015). Therefore, these characteristics make coastal cities particularly vulnerable to the impacts of climate change. One of the forecasted impacts of climate change in these areas is the increase of coastal floods due to rising sea level and storm surges. In this context, urban planning plays a key role in urban adaptation. However, even though the interest in this topic is increasing, operative support and tools for planning urban adaptation for cities are in short supply, especially for coastal cities. To date, urban adaptation has been mainly based on the concept of vulnerability and several vulnerability indices have been developed for supporting decision makers in the adaptation process of coastal areas, especially on the territorial level, grounding on a sectoral perspective. As a consequence, the adoption of this approach does not allow to take into account the complexity of the coastal urban system and, thus, all the features and their relationships that can affect the effectiveness of the urban measures to implement in the process of urban adaptation. Based on these observations, the purpose of this research was the development of a new decision support tool that allows the most suitable urban actions to be identified for increasing the capacity of cities to deal with coastal flooding events due to future rising sea level and storm surges. Besides the use of the most innovative GIS-based technologies, one of the novelties introduced with this work was the adoption of the holistic-system approach for the tool development, such as in the case of the definition of the new composite index based on the more holistic concept of urban resilience. For what concerns the development of the GIS-based tool, a four-phase methodology was defined. The first step was the definition and development of a novel composite index for a quantitative evaluation of the “urban coastal resilience” on the local level, named Coastal Resilience Index (or CoRI), by the Analytic Hierarchy Process (AHP) (Saaty, 1980), supported by the Delphi Method. In particular, the CoRI index allows the identification of four resilience levels (high, medium-high, medium-low and low). In the second step, since the urban adaptation measures should be defined in relation to physical and functional characteristics of the urban context, a classification of urban coastal areas was introduced, by specifying Urban Coastal Units (UCUs) depending on their urban density and land use. Considering the CoRI levels and the UCU classification and according to the coastal adaptation approaches defined by the IPCC (Nicholls et al., 2007), in the third phase, four classes of Urban Adaptation Actions were defined. In detail, a matrix that puts in relation the Urban Adaptation Actions classes with UCUs and CoRI levels has been developed. In relation to these three main phases and considering the potentialities of GIS applications in urban planning, in the last phase, a design workflow for developing the GIS-based tool was defined. Thanks to this workflow, the GIS-based tool was implemented and applied to a study area in the city of Naples. In particular, the identification of the potential coastal floodplains of Naples was useful for selecting the study area that includes five neighbourhoods - Barra, Mercato, Industrial Zone, Pendino and San Giovanni a Teduccio - localized in the eastern part of the city. Hence, the input data of the area chosen for the tool's implementation were collected. According to the methodology aforementioned, the GIS-based tool was realized considering three toolboxes: the “Coastal Resilience Index Tools” toolbox, the “Urban Coastal Units Tools” toolbox and, finally, the “Urban Adaptation Actions Tools” toolbox. From the application of the GIS-based tool to the study area, the main findings were the following ones. About the CoRI, the study area is characterized by a high presence of urban areas with medium-low resilience levels (61% of the study area) and by the absence of urban areas with high resilience levels. Concerning the UCU, the urban area is characterized by a high physical and functional complexity of the urban area. Therefore, the majority of the study area is classified as UCU 1 (i.e. high-density and mix-used developments) and UCU 2 (i.e. mono-functional zones, transport infrastructure, public facilities), while the absence of natural areas is noted. Regarding the identification of the Urban Adaptation Actions, all the UCUs need to enhance their resilience level through the implementation of fitting urban measures due to the absence of urban areas characterized by high resilience levels and the high urbanization degree of the study area. In particular, in the majority of the area (about 61%), it is necessary to implement a mix of “hardware” and “software” measures. Therefore, urban transformations should be addressed towards the realization or improvement of protection infrastructure systems, the use of resilient design standards at building scale and the reduction of land-use intensity through the delocalization of critical facilities from the coastline. From an urban planning perspective, the application of the GIS-based tool to the study area in Naples highlights how the urban layout and spatial organization can affect the urban capacity to deal with coastal flooding. Indicators that compose the CoRI enable the in-depth study of urban contexts, and identify areas where there are major shortcomings in terms of urban resilience. Whereas the Urban Coastal Units classification enables the categorization of coastal areas in relation to their land use and land-use intensity in order to better identify the most appropriate “palette” of urban adaptation actions to implement. The identification of a set of urban actions for different urban typologies can be useful for not only defining and programming new urban transformations but also for allowing decision-makers to monetize possible interventions to carry out. In conclusion, urban transformations will be more and more necessary in order to adapt urban areas to future impacts due to climate change. Therefore, in order to better deal with the forthcoming climate change impacts on cities, the novel methodology provided in this study sets the framework for the development of new urban planning tools capable to cope with other climate impacts and, eventually, for their integration in order to develop a comprehensive tool for urban adaptation to different possible impacts of climate change (Wardekker et al., 2010).

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