A Fuzzy Multicriteria Categorization of Water Scarcity in Complex Water Resources Systems

Although water scarcity is a well-understood concept, it is difficult to define it precisely and furthermore, to address the water scarcity which requires a complicated set of water actions. In this work, with the aim to face the complexity of water scarcity, we propose the establishment of several categories in order to characterize the water scarcity. These categories are guided by the corresponding roadmap so as to address the water scarcity. Consequently, the considered categories are used to characterize the scarcity are non-ordered. The methodology is based on a developed fuzzy multi-criteria filtering approach. The Water Demand Satisfaction, Water Reliability, Management Effectiveness and Water Sustainability, are selected as criteria. Each category is characterized by reference to a fictitious alternative, the prototype. Τhe water scarcity categorization process is based on the fuzzy binary comparison between the water scarcity evaluation of the criteria in the watersheds and the prototype of each category. This binary comparison over all criteria consists of the concordance and non-discordance principle. The use of fuzzy analysis enables us to express the grey region of the monocriterion comparison between the basins and the prototypes and furthermore, to achieve a suitable aggregation of the achieved monocriterion comparison between the basins and the prototypes. Eventually, the use of the veto thresholds and discordance indices of the fuzzy aggregation allowing compensation, are to be avoided when criteria are strongly conflicting, which is a very useful property in classification problems. The described methodology was applied to the Ebro river basin, identifying the existing problems.