Multistage Many-Objective Optimization Solution Method for Battle of Intermittent Water Supply

This paper presents a comprehensive framework for applying multistage many-objective optimization methods to the Battle of Intermittent Water Supply (BIWS) problem, as part of the WDSA & CCWI 2022 conference. Given the complexity of the interventions and the time-consuming nature of hydraulic simulation, a multistage strategy incorporating optimization techniques and prior judgement was developed to sequentially reduce the search space. The framework consists of five stages: preliminary analysis, search space reduction, optimization of rehabilitation, optimization of regulating rules, and refinement of the final solution. The optimization model considers four objectives selected from nine performance indicators, focusing on pressure levels, leakage reduction, energy usage, and system equity in supply. The methodology was successfully applied to the BIWS case. The results across six planning scenarios show that computation time was significantly reduced while achieving near-optimal solutions.