Multi-Criteria Pressure Management Optimization for Non-Revenue Water Reduction in a Semi-Arid Metropolitan Water System

Escalating water scarcity and tightening regulatory targets have intensified the need for systematic non-revenue water (NRW) reduction strategies in metropolitan utilities. This study develops and validates an integrated hydraulic–multi-criteria decision framework for pressure reducing valve (PRV) set-point optimization in a large-scale semi-arid water distribution network. The methodology combines calibrated dual-platform hydraulic modelling (EPANET 2.2 and MsSu), International Water Association (IWA)-standard water balance analysis, and group-based multi-criteria decision analysis using the Analytic Hierarchy Process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). The framework was applied to a metropolitan system in semi-arid Türkiye serving 2.32 million inhabitants. Twelve scenarios, including the baseline and PRV settings between 25 and 35 m, were evaluated using six criteria: average pressure, minimum nodal pressure, current annual real losses, recoverable real losses, infrastructure leakage index, and minimum night flow. Results show that a 30 m setting maximizes leakage reduction but approaches minimum pressure limits, while PRV = 35 m provides the best overall balance across criteria.