A Comparative Analysis of Multi-Criteria Decision Making Methods in Optimizing Water Loss Management Strategies used in Water Distribution System

Abstract

This paper presents a comparative analysis of Multi-Criteria Decision Making (MCDM) methods integrated with numerical optimization technique to optimize water loss management strategies used in the water distribution system. The study was conducted at Moshi Urban Water Supply and Sanitation Authority (MUWSA), Tanzania. Two ranking methods, Complex Proportional Assessment (COPRAS) and Simple Additive Weighting (SAW) integrated with Integer Linear Programming (ILP) technique were compared. The aim is to help decision-makers to choose the best decision-making method that may help to optimize the water loss management strategies used in water distribution systems. The Multi-Criteria Decision Making methods were used in evaluating and prioritizing the strategies while the Integer Linear Programming technique was used to formulate a decision model and selecting the best strategies (alternatives) employed in water loss management. Results show that the methods rank the given alternatives differently while when integrated with integer linear programming technique, the formulated models select the same portfolios of alternatives. Both models select thirteen alternatives, which cost 97% (TZS 235.71 million) of the total budgets set by the water authority for WLM. Furthermore, the models showed robustness to their results; when the ranking of evaluation criteria changes, the portfolios of alternatives remained the same. In general, this paper elaborates how decision-making methods can be coupled with mathematics in operation research to solve issues in water management and planning.