A fuzzy group decision-making model for Water Distribution Network rehabilitation

Group Decision-Making (GDM), though could aid water companies in determining the Pipeline Rehabilitation Plans (PRPs) in any network size, can impose uncertainties on PRPs due to the different viewpoints of decision-makers. Thus, it should be determined when GDM could be ignored or should be considered for PRPs. To address this problem, a Fuzzy GDM model was developed to assess 10 scenarios of GDM in combination with 7 scenarios of network size. Hence, by participating experienced experts in different countries, PRPs were determined for various network sizes in a case study. The results indicated that the GDM could be ignored for PRPs with fewer pipes, whereas, should be considered for PRPs with more pipes. In addition, it was found that the groups with more decision-makers had less effect on pipes prioritization, but more influence on determining rehabilitation strategies. While, in groups with fewer decision-makers, the GDM could have the reverse effect.