Multicriterion Design of Long-Term Water Supply in Southern France

Abstract

A multicriterion decision-making (MCDM) methodology is developed to design a long-term water supply system involving multiple actors. A 1989 regional development plan for augmenting water resources in the Adour-Garonne Basin (southwestern France) is used to illustrate the approaches. The specific problem of the choice of a site for building a large reservoir is investigated. The problem elements consist of four actors, 13 criteria, and 38 alternatives. The first phase of the methodology, the ELECTRE III technique, is used to screen alternatives and reduce the choice set to eight “efficient” alternatives, which are then examined in some detail. In the second phase, the multiactor multicriterion decision process is modeled by means of an extension of ELECTRE III. The solutions thus obtained are compared to the outcomes of the actual decision process. The similarities and differences between the model and reality are used to assess the suitability of that approach.