TUE1.2: Natural hazard resilient cities
Time: Tuesday, 28/Aug/2012: 8:30am - 10:00am
Session Chair: Damien SERRE, EIVP
Location: Flüela

Session organized by Université Paris-EST, EIVP


Natura hazard resilient cities

Damien SERRE1, Richard LAGANIER2

1Université Paris-EST, EIVP, France; 2Université Paris Diderot, Laboratoire PRODIG, Sorbonne Paris Cité

2007 is a crucial year: 50% of the population is living in urban areas. Furthermore, it has been forecasted that this number will double in the next 30 years. This increase rate corresponds to a new city of 1 million people every week during the next 40 years. This exponential curve is enough to imagine that cities become more vulnerable: issues we will have to face dealing with risk management become more complex. Moreover, this quick urbanization comes with climate change uncertainties. Climate change, coupled with people and asset concentration in cities, is the worst combination to set up a sustainable natural hazard management plan. As an example, floods are considered the major natural hazard in the EU in terms of risk to people and assets. Currently, more than 40 bn € per year are spent on flood mitigation and recovery in the EU. More than 75 % of the damage caused by floods is occurring in urban areas. Climate change and concentration of population and assets in urban areas are main trends likely to affect these numbers in the near future. Global warming is expected to lead to more severe storm and rainfall events as well as to increasing river discharges and sea level rise. This means that flood risk is likely to increase significantly. At least, urban systems contain assets of high value and complex and interdependent infrastructure networks (i.e. power supplies, communications, water, transport etc.). The infrastructure networks are critical for the continuity of economic activities as well as for the people’s basic living needs. Their availability is also required for fast and effective recovery after disasters (floods, hurricanes, earthquakes, landslides...). The severity of damage therefore largely depends on the degree that both high value assets and critical urban infrastructure are affected, either directly or indirectly.

In this context, we obtain a urban society: (1) more and more menaced by a lot of natural hazards; (2) more and more vulnerable due to increasing issues and complex urban system relations; (3) less and less resilient.

This session aims at discussing how researchers, practitioners and professionals are integrating the resilient concept to set up new risk management approaches and to design more resilient and flexible cities to face all types of natural hazards. Indeed, a lot of projects in the EU are now trying to use the concept of resilience to mitigate different types of risks in urban areas. This session represents a great opportunity to exchange on resilient cities and to build up a resilience framework. We are attending presentations combining different disciplines, bringing conceptual elements on resilience but also tangible applications. All methods, frameworks, tools (GIS) designed to reduce risks in cities and integrating the resilience concept are welcome in this session.

Floating ecocities as a strategy to reduce the vulnerability of delta areas

Rutger De GRAAF1,2

1Rotterdam University of Applied Sciences, Netherlands, Kingdom of the; 2DeltaSync, Delft, the Netherlands

Delta areas all over the world face multiple interconnected problems. They are increasingly threatened by flood damage, land subsidence, sea level rise, and extreme weather events. Another challenge is how to accommodate a huge increase in population while at the same time reducing the pressure of delta areas on the environment. Starting from a theoretical framework of vulnerability, this presentation demonstrates the concept of floating productive urbanization based on cyclic resource flows in vulnerable delta areas. A floating ecocity adapts to any future water level and can also be flexibly adapted to changing societal needs. The objective is to achieve a positive impact on the environment by using waste products of delta areas, and to create pleasant living conditions for involved and resilient communities. The presentation elaborates on the urban metabolism and the resilience of the floating ecocity. Moreover, various key governance, design and technical elements for the realization of floating ecocities will be presented.

Flood risk management – creating efficiency by stakeholder involvement

Heinrich WEBLER

Stadtwerke Mainz AG, Germany, Federal Republic of

In the German federal state of Rheinland-Pfalz the state of the actions according to the EU Flood Directive has reached afar: The preliminary assessments, the flood hazard maps and the risk maps are finished for the whole state. In the beginning of 2011 the flood risk management plan for the catchment area of the complete river system of the Nahe (4.000 km²) has been started. It follows the German LAWA-directive “Recommendations for the Establishment of FRMP” with its FRM cycle for diverse areas of actions. Ap-propriate objectives and structural as well as non structural measures have to be proposed. The pilot character of the Nahe project is to visit the stakeholders and to work out the objectives and measures together with them in a series of workshops. Four workshops have taken place concerning the areas of actions: “emergency planning”, “providing information”, “natural water storage”, and “landscaping - pre-cautionary land use”. The workshops have identified a wealth of good ideas among the communities and have promoted stakeholder “buy in” to the process. This is being achieved much earlier and in a much more constructive manner than would have been anticipated following a more traditional approach in-volving the circulation of draft proposals to the public for information and comment.

Promote urban resilience through collaborative urban services management

Marie TOUBIN1,2,3, Jean-Paul ARNAUD1, Damien SERRE2, Youssef DIAB2, Richard LAGANIER3

1Egis, France; 2Université Paris-Est, EIVP, France; 3Université Paris-Diderot, UMR PRODIG, France

Urban resilience is a trendy concept taking into account multi-scalar interactions within the urban system: short and long-term impacts, spatial dependencies and inequalities. The concept seems relevant to assess the performance and sustainability of cities of tomorrow, whatever changes and disturbances they might face. The issue now, is to enable local authorities and urban stakeholders grasping and applying the resilience approach. Our research highlights the need for collaboration and integration in managing a resilient urban system. The technical networks and urban services supporting urban development are an interesting case study to apply resilience concepts and demonstrate the effectiveness of integration and collaboration. Indeed, urban services are both a major issues in sustainable cities and in facing disturbances (natural hazards, climate change, industrial accident, …). And yet, the management of urban services lacks integration and communication in spite of the strong interactions existing between them. For local authorities, promoting an integrated management of urban services, in collaboration with urban planning and risk management is essential to ensure consistency and efficiency of urban policies. Our research aims at developing method and tools to help local authorities in identifying interdependencies between urban services, assessing their behavior in case of disturbances and, above all, involving urban services managers on resilience and sustainability issues. First, an auto-diagnosis realized with each manager identifies the dependencies of the service, then the workshop around crossed-information raises awareness of managers to their interdependencies. With the organizing authority, they are led to express their difficulties in managing these dependencies on both technical and organizational aspects. A second workshop is held to discuss technical and organizational measures that could solve those problems in an integrated approach. The case study with the City of Paris demonstrates the relevance of the approach and outlines the future developments in improving urban resilience.