Making urban territories more resilient to flooding by improving the resilience of their waste management network. A methodology for analysing dysfunctions in waste management networks during and after flooding
Résumé
In view of all the damage caused by flooding that has affected large numbers of regions throughout the world over the last ten years, urban areas appear to be little prepared for facing up to this type of catastrophe. Today, improving their resilience, i.e. their capacity to recover rapidly after flooding, appears to be a real issue at stake in societies' sustainable development. Due to their organization in the form of subsystems , the multiple aspects of their functions and the dynamics that drive them, these urban territories must be considered as complex systems . Within these urban systems, technical networks are physical links between inhabitants and the actors involved, the symbolic links of belonging to the same community, to the same organized territory (Lacoste quoted by Dupuy, 1991). As supports and even objects of interactions between the different sub-systems in the urban system and with the outside environment, they supply, unify and irrigate all the constituent elements of urban territories. In this way, networks participate in organizing and regulating the system by being the vector of relations between its different constituent elements. "Physically connecting the elements in the system unifies them and creates the network's operating conditions at the same time. In the same way, it makes a certain mode of operation and evolutions in the system possible" (Dupuy, 1984). This strategic position makes networks extremely influent in the dynamics of maintaining the global urban system. In turn, they can be generators of incidents by interrupting flows or vectors in the propagation of unforeseen turns of events. Therefore, characterizing their resilience to flooding may prove to be interesting in for providing a better understanding of urban resilience. In this context, we have decided to work on the resilience of waste management networks. Because they raise essential questions on sanitation and public health and because they often have a strong visual and psychological impact, these networks appear to be real issues at stake in crisis management. After flooding, the volume of waste generated is often significant and of a different sort (mixed, even polluted wet waste). Faced with this situation, waste management poses a real problem. What should be done with this waste? How should it be collected? Where can it be stored? How should it be processed? Who is in charge? Providing answers to these questions is all the more strategic inasmuch as post-flood waste is the visual sign of the catastrophe. As a result, cleaning up is populations' and local actors' first reflex in order to forget what has happened, but also in order to start up again as quickly as possible. Therefore, it would appear primordial to improve waste management networks' resilience to flooding (Beraud et al., 2010). First and foremost, improving the resilience of an organization requires understanding the way it operates in order to identify what dysfunctions it may contain. A methodology needs to be developed for this purpose, capable of analyzing a waste management network's way of operation under normal and crisis conditions. In this way, risks and potential dangers resulting from the urban system being flooded can be identified and the means of prevention for improving the waste management network's resilience to flooding can be brought out. Choosing the right methodology is not an easy task. Numerous methods of risk analysis exist. For the most part they are of industrial origin. As a result, it is not always easy to use them for studying social systems such as urban technical networks, as these systems possess characteristics that differ considerably from industrial systems. "Multiple responsibilities with regard to the design, build, operation and maintenance of networks, separated amongst numerous actors who do not regularly communicate together and share information" are, for example, one of the particularities of risk control in an urban environment (Prost, in Blancher, 1998). As a result, the way in which networks operate may appear to be extremely complex: the diversity and involvement of actors, different scales and territories to be taken into account, the issues at stake concerning the public service mission, catastrophic consequences, that are immediate and those with important repercussions when they are interrupted, etc. This complexity makes it extremely difficult to model urban networks (Maiolini, 1992), whereas applying methods used in the world of industry requires that models are created beforehand. Therefore, there are real methodology stakes in play when transferring these methods from industrial engineering to urban engineering. This article will present the methodology set up followed by initial results. - See more at: http://ascelibrary.org/doi/10.1061/41170%28400%2952#sthash.2IxqVsej.dpuf