Optimal Design Method of WDNs ConsideringTopology Using a Reliability Analysis

This study presents a quantitative framework for selecting the optimal inlet point in the design of new looped water distribution networks (WDNs). The approach integrates network topology analysis, in which betweenness centrality is computed to identify candidate inlet nodes, with a pipe diameter optimization model applied under identical objective functions and constraints. For each inlet point scenario, hydraulic reliability, expressed by the Resilience Index (RI), average water age, and design cost were evaluated. The analysis revealed that inlet points with higher betweenness centrality consistently reduced average water age, and in certain cases—such as the fourth inlet point scenario—improved RI by approximately 12% compared to the baseline. Although this configuration required a marginally higher design cost, it was determined to be the most suitable option considering long-term supply stability and operational efficiency. The proposed framework provides a practical decision-support tool for balancing hydraulic reliability and economic feasibility in the planning and design of new WDNs.