Computer-Aided Decision-Making Model for Multiphase Upgrading of Aged Water Distribution Mains

This study introduces a decision support system for upgrading aged water distribution mains. The network hydraulics is simulated and evaluated by a hybrid reliability measure, and the design period is divided into multiple upgrade phases. In each phase, a multiobjective optimization problem is solved to derive the trade-off between construction cost and network performance reliability. Subject to budget constraints, upgrade decisions, including those related to pipe replacement and laying parallel pipe, are made, leading to a more robust hydraulic performance of the network over time. To implement multiphase upgrade programs, three approaches are introduced, varying in their assumptions regarding design and construction methods. These approaches are applied to a real case study, and results indicate that the dynamic phase-by-phase design and construction approach is computationally efficient and cost-effective while satisfying physical and performance constraints over the simulation time horizon.