| Our modern societies, ever more technologically efficient, are also increasingly vulnerable to failures in lifeline networks (LN), like electricity grids, natural gas, water, telecommunications, transportation, etc. Indeed, on the one hand, they have become increasingly dependent on these LN and on the other hand, these LN themselves have become highly interdependent. Thus, the failure of a LN can cause a chain reaction on other networks, causing unprecedented disasters. Moreover, because of the increasingly close proximity between the LN's infrastructures in urban areas, geographic interdependencies have appeared. Indeed, the uncontrolled spread of a LN's dangerous substance may have effects in an impact area that can have consequences on other LN.;In a context where few studies leading to tangible results have been carried out, the need to develop operational tools, easy to implement and to use, justifies such a study on geographic interdependencies.;Therefore, the research presented in this paper proposes a methodology to identify, characterize and evaluate geographic interdependencies between LN. The ultimate objective was to enable the implementation of mitigation measures in critical areas. It led to the creation of tools in order to assess the vulnerability of sectors in terms of geographic interdependences and determine their criticality degree, thanks to vulnerability tables and sectors criticality maps. Moreover, these tools are able to integrate an expert system by providing additional analysis to identify and prioritize mitigation measures against risks generated by geographic interdependencies. This methodology has been applied to the city of Montreal and led to a discussion of its applications by the LN's risk management professionals.;The purpose of this study is to equip and guide LN's managers in their decision-making in the face of such issues. Therefore, this work should ultimately help each LN to protect them from failures transmitted by the LN with whom they have spatial dependence links, which contribute to make our societies less vulnerable. |
