BUILDING CITY RESILIENCE THROUGH A DETAILED KNOWLEDGE OF THE BEHAVIOR OF OUR URBAN SYSTEMS DURING CRISIS EVENTS

The main objective of RESCCUE project is to help cities around the world to become more resilient to physical, but also social and economic challenges by generating methodologies and planning measures and strategies to bring this objective to practice and make them applicable to different types of cities, with different climate change pressures.

Specifically, RESCCUE aims to improve urban resilience of our cities through a set of models and software tools that, first, assess climate change impacts in several sectors like water cycle (water treatment, water supply, urban drainage), waste water treatment, transport, energy supply, and solid waste, and then interconnects them to assess urban resilience for the current state and a wide range of potential future scenarios.

In this framework the detailed knowledge of the behavior of our urban systems during extreme climate events represents the initial basic piece of the whole process of the city resilience assessment. The possibility to share information, technical background and learned lessons from past experiences among technicians, utility and city managers is, definitely, a good starting point to build this knowledge. Notwithstanding, the use of detailed models and software tools (likely known as sectorial model within the project) is essential to analyse the behaviour and the response of strategic services and critical infrastructures with respect to specific pressures and drivers related to climate change. Moreover the outputs of these sectorial models will be used to assess hazard, vulnerability and risk levels related to the above mentioned pressures/drivers for current and future scenarios where a large set of measures and strategies will be simulated and evaluated in terms of impacts reduction.

Once the detailed knowledge of each urban service has been acquired through available data, past experiences and simulation results, then the interconnections between them and the cascade effects due to failures or extreme climate events can be studied.

This second step in RESCCUE is treated in two different ways:

1. In the WP2 and WP3 the analysis (in terms of hazard and risk) of certain impact events could be achieved via the use of loosely coupled models and tools

2. In the WP4 by the use of a holistic tool (HAZUR) to analyze the relations and the cascade effects among the different urban services analyzed in the three case studies during crisis events

It is clear that integration of all the models and tools representing the whole spectrum of the urban services analyzed in the project in the three RESCCUE cities is not feasible, but this is not the aim of the use detailed integrated model (this approach, with a holistic view and a consequent minor level of detail is covered by HAZUR). The aim of the integration of models is the detailed analysis of hazard and risk produced by complex interactions and cascade effects involving different urban sectors.

So, inputs of hazard/risk models can be used to generate outputs that could be fed into a subsequent hazard/risk model. As an example, the water distribution network is at risk due to seasonal variations of temperature and that these risks are expected to increase as a result of climate change. The impact of temperature on the water distribution network can result in cascading effects on other services. A pipe burst scenario could lead to flooding that can lead to energy grid failure and traffic disruption. On the other side, heavy storm events may produce flooding problems with direct and indirect impacts like economic damages, traffic disruption, combined sewer overflows into bathing waters with consequent potential hazards for citizens but, also, indirect impacts in leisure activities, tourism and fishing sector.

An accurate analysis of these impacts requires the implementation and integration of detailed and reliable models and tools (the RESCCUE sectorial models). In this way, it could be possible to carry out an exhaustive multi-criteria analysis for determining direct and indirect impacts produced by extreme events in a context of climate change and to assess all the potential benefits of the adaptation measures to face with it.