A T-Spherical Fuzzy Set Approach to Develop a Fuzzy Ranking Index for Water Resource Management in the Philippines.

A water poverty index (WPI) is a multi-criterion indicator that assesses water stress and scarcity that integrates the physical estimates of water availability with the socioeconomic drivers of poverty. However, the decisionmaking process can be a participatory, iterative process that is characterized by uncertainty due to ambiguity, impreciseness, or incomplete information. This study focuses on the development of a fuzzy ranking index based on the T-Spherical Fuzzy Set under a multi-criteria framework. An illustrative case study on measuring the WPI is presented in the ranking of the vulnerability of a municipality, in tLuzon Island, Philippines. In this assessment, the main contributors to water poverty in the area include water availability, lack of access to safe water and capacity to manage the development of water sources. This linguistic approach to score indicators was found appealing and took into consideration the uncertainty in assigning linguistic assessments by participants. There remain other aspects of the decision-making process that can be improved such as compositing several sub-indicators of each WPI; building consensus among multi-stakeholders and using the same process to rank alternatives to reduce water poverty. [ABSTRACT FROM AUTHOR]