Group Evaluation of Water Management Plans with Analytic Hierarchy Process and Social Choice Methods

Selection of a good water management plan for the river basin is a complex decision-making problem because interests of stakeholders are rarely in complete agreement. If water committee has to emulate interest and power of key parties, decision-making process can be organized in many different ways, depending on adopted methodology for deriving decisions and formalizing setup to implement solutions. Group context brings individuals with different background, attitude, and (in)consistency they will demonstrate when evaluating and/or judging options. This chapter shows how methodologically distinct tools can efficiently support group decision-making at a group and sub-group level within water committee. We propose to firstly use analytic hierarchy process (AHP) to rank management plans in strictly multi-criteria environment and, secondly, to use social choice (voting) methods Borda Count (BC) and Approval Voting (AV) for the final ranking of reduced set of top-ranked plans as identified in the AHP. Illustrative example from Brazil is used to show usefulness of combined approach.