A Sorting Model for Group Decision Making: A Case Study of Water Losses in Brazil

Many water supply systems in Brazil have serious problems related to the high index of water losses, which provokes financial and environmental impacts. This is an immediate consequence of an inadequate maintenance plan, allied to natural and budgetary constraints. In addition, in these types of problems it is commonplace to consider the opinions of many managers, such as those from the operational, environmental and financial sectors of Water Companies. In view of this, a sorting multicriteria model to support group decision making is developed. We proposed an approach which sorts the areas of the system which are located in critical zones of water losses into categories, and which takes into account different points of view and considers uncertainty in criteria weights by using only ordinal information, so as to make it viable to manage the maintenance plan and to use the scant financial resources more efficiently. The SMAA-TRI method is used to tackle the group sorting problematic by categorizing the network into zones where losses are intense and thus to focus the managers’ effort on the most critical regions. A case study in Brazil is presented to demonstrate the efficiency of the approach proposed.