Rehabilitation of sewer networks : addressing socio-economic impacts in the CARE-S project

Rehabilitation of sewer networks has to serve various objectives, both in terms of present general performance, and in terms of long term sustainability. Part of these stakes are external to the sewerage utility operation, such as social impacts of sewer failures, or social impacts of works. Knowledge and assessment of social and economic external costs have been addressed in a component of project CARE-S, supported by the European Commission. This project has developed a decision support environment and software prototype, including different tools to assist decision-makers in the different tasks necessary to pipes rehabilitation planning and programming. The aim of the work presented here was to help addressing the socio-economic (indirect, or external) costs linked to rehabilitation, i.e impacts of failures and impacts of rehabilitation works to third parties, by providing guidance and methods for assessing criteria representing these social costs: ·decision criteria for comparing a limited set of technologies when considering a given single pipe (impacts of rehabilitation works), ·decision criteria for comparing various pipes candidate to rehabilitation, given the related failures or failures hazards (impacts of failures). The two sets of criteria are to be used in two respective multi-criteria selection tools, together with other criteria.