Knowledge-based decisions for asset management of urban water infrastructure in Iran and Brazil using a nominal-based multi-criteria group decision method

Asset management of the Urban Water Infrastructure (UWI) is typically faced with limitations regarding uncertain operational data. This shortcoming can be improved using the knowledge-based decisions of experienced experts. However, since knowledge-based decisions depend on decision-makers' knowledge and experience, verifying their results in various regions is essential. This subject was addressed in this research. Hence, four groups of experts in Iran and Brazil collaborated to assess the criteria effective in the Maintenance-Rehabilitation Planning (MRP) of urban water pipes. For this purpose, a nominal-based multi-criteria group decision-making method was developed. To verify the results of this method, the viewpoints of non-weighted and weighted decision-makers were investigated and compared pairwise. The findings of this research improved the asset management of the UWI in Iran and Brazil by identifying the criteria applicable to the MRP of the pipes based on knowledge-based decisions. Likewise, it was found that weighting the experts has no decisive effect on the results and is only effective in groups where the decision-makers' weights are identically distributed. Moreover, it was shown that there is a relationship between the similarity of results and the similarity of experts' profiles in knowledge-based decision groups of various countries such as Iran and Brazil.