MULTICRITERION DESIGN OF LONG-TERM WATER-SUPPLY IN SOUTHERN FRANCE

A multicriterion decision-making (MCDM) methodology is developed to de sign 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 approac hes. The specific problem of the choice of a site for building a large reservoir is investigated. The problem elements consist of four actor s, 13 criteria, and 38 alternatives. The first phase of the methodolog y, the ELECTRE III technique, is used to screen alternatives and reduc e the choice set to eight ''efficient'' alternatives, which are then e xamined in some detail. In the second phase, the multiactor multicrite rion decision process is modeled by means of an extension of ELECTRE I II. The solutions thus obtained are compared to the outcomes of the ac tual decision process. The similarities and differences between the mo del and reality are used to assess the suitability of that approach.