Bruno Barroca

Analysing urban resilience through alternative stormwater management options: Application of the conceptual Spatial Decision Support System model at the neighbourhood scale

Recent changes in cities and their environments, caused by rapid urbanisation and climate change, have increased both flood probability and the severity of flooding. Consequently, there is a need for all cities to adapt to climate and socio-economic changes by developing new strategies for flood risk management. Following a risk paradigm shift from traditional to more integrated approaches, and considering the uncertainties of future urban development, one of the main emerging tasks for city managers becomes the development of resilient cities. However, the meaning of the resilience concept and its operability is still not clear. The goal of this research is to study how urban engineering and design disciplines can improve resilience to floods in urban neighbourhoods. This paper presents the conceptual Spatial Decision Support System (DS3) model which we consider a relevant tool to analyse and then implement resilience into neighbourhood design. Using this model, we analyse and discuss alternative stormwater management options at the neighbourhood scale in two specific areas: Rotterdam and New Orleans. The results obtained demonstrate that the DS3 model confirmed in its framework analysis that stormwater management systems can positively contribute to the improved flood resilience of a neighbourhood.

Contributing to urban resilience to floods with neighbourhood design: the case of Am Sandtorkai/Dalmannkai in Hamburg

On‐going changes in cities caused by rapid urbanisation and climate change have increased both the flood probability and the severity of flooding. Consequently, there is a need for all cities to adapt to climate and socio‐economic changes by developing new strategies for flood risk management. The following risk paradigm shifts from traditional to more integrated approaches, since one of the main emerging tasks for city managers is the development of resilient cities. The concept of resilience is becoming more and more important, despite the many challenges that interfere with its implementation. The goal of this research is to create knowledge on how to operationalise flood resilience at the neighbourhood level through neighbourhood design. A research approach was used and a qualitative analysis tool, the DS3 model, was developed in order to study a particular neighbourhood of HafenCity, in Hamburg. Results show that design measures involving transportation infrastructure, land use (open public spaces) and buildings have been the main contributions to the flood resilience of the neighbourhood.

Resilience and Vulnerability Analysis for Restoration After Tsunamis and Floods: The Case of Dwellings and Industrial Plants

The resilience approach represents a unified and integrated framework for the restoration process following disasters. Under given resilience parameters values, a resilient system is able to recover and be strengthened within a defined recovery period; otherwise, it is a non-resilient system. This chapter considers different structures and focuses on several parameters which govern resilience together with their mechanical vulnerability under various hazards. A new method of theoretically measuring resilience, its link with mechanical vulnerability, and its sensitivity analysis are investigated for dwellings and industrial plants under the effects of flood and tsunami hazards: Non-designed (informal) masonry constructions under the effects of a flooding hazard: vulnerability is estimated after a rapid inspection by qualified engineers. Fragility curves are developed and the structural failure risk is calculated and mapped depending on the intensity of the hazard: water height and flow velocity, in a real case. Structural and non-structural waste generated by flooding: relevant models are adopted and used for predicting expected quantities of waste. The territory may take several years to recover since generated waste may represent several times annual quantities produced under normal circumstances. Coastal industrial plants under the effects of a tsunami hazard: structural failure in tanks results from buoyancy (uplift), overturning, sliding by shear effect, excessive bending, or buckling. Vulnerability and fragility curves are developed for various tanks of small and large sizes.

Urban Flood Mitigation: Sustainable Options

Cities have started to anticipate the effects of global warming dealing with flood management. Indeed, it seems that this last decade, flood risk has increased and cities are facing on the one hand more frequent hazards, and on the other hand different types of flooding: fluvial, coastal, estuarial and pluvial. Most cities have to manage at least two of these flooding types. At the same time, flood risk management practices have changed step-by-step. Indeed, despite efforts made to maintain the flood defense assets well, we often observe failures leading to finally increase flood risk in protected areas during major flood events. Moreover, flood forecasting models, although they benefit from continuous improvements, remain partly inaccurate due to uncertainties populated all along data calculation processes. This means cities cannot continue to manage flood risk only by the use of flood defenses: sustainable options have to be designed to better mitigate the effects of flooding in urban area and in a long term strategy. Several European cities have suffered recent flooding events. It was the case for example in 2007 in United Kingdom. During this period, major events came from extreme rainfall and it appears that pluvial flood risk has become one of the most frequent events. In this context, flood risk can appear on every territory: cities have to develop some methods to take into account this new deal, options to achieve urban flood resilience. Some solutions that cities are using or will be able to set up in the near future will be described.

Modeling disruptions causing domino effects in urban guided transport systems faced by flood hazards

Flood risks are the most frequent natural risks in the world. Their consequences are particularly serious when they affect technical systems in urban areas. Experience feedbacks on guided transport systems show that they are urban technical systems that are particularly vulnerable to this type of natural risk. The resilience concept is used in a systemic approach for making an accurate analysis of this type of natural risk. The purpose of this article is to provide an analysis of guided transport systems’ resilience in the face of flood risks via a study of the failure mechanisms to which component elements of these systems are subjected. By using methods resulting from operational safety concepts and designing a computer tool, all the failure scenarios for components can be produced, together with their domino effects. In this way, our work provides a methodology for characterizing guided transport systems’ vulnerability in the face of natural risks and for comparing this vulnerability depending on whether the system is in an underground, ground-level or overground configuration.

Integrating flood defence fragility to measure built environment vulnerability - a GIS based approach

More and more floods occurred over the last decade in the world, causing important damages. Moreover, levees are often not well maintained, so they hardly resist to major floods and can break easily. At French national scale, the length of levees, estimated to 7500 kilometers, and the lack of data all along these infrastructures complicates their management. In this frame, levee managers need approaches and tools in order to be helped in their maintenance decision. The goal of our research is to develop methods modeling levee failure mechanisms and allowing performance levee assessment. These methods integrated in an existing GIS dedicated to levee management will contribute to obtain a spatial decision support system aiding levee managers in their maintenance decision. Finally we made some tests in a specific area to integrate in the SDSS the level of vulnerability behind dikes to improve the levee manager decision process.