Multiobjective Game Theory Model for Identifying Proactive Pipeline Rehabilitation Strategies in Water Distribution Systems

Water distribution systems (WDSs) are crucial infrastructure for communities, and their substantial growth due to urbanization has increased their vulnerability to high-consequence hazards, such as earthquakes. Water utilities face challenges in making informed decisions for proactive pipeline rehabilitation to ensure WDS absorptive resilience at minimal cost, especially in the aftermath of disastrous events. However, the nature of these goals is inherently conflicting. Existing optimization models for proactive pipeline rehabilitation assume collaboration and harmony in achieving these conflicting goals, neglecting the need to consider all of them in the decision-making process. Establishing a decision-making process that addresses these conflicting goals is essential to balance them effectively. This study proposes a multiobjective game theory model (MOGM) for proactive pipeline rehabilitation, balancing costs, and absorptive resilience of WDSs. A simulation-based approach is employed, representing two objective functions as two groups of players: minimizing rehabilitation cost by the “cost player,” who aims to minimize the total rehabilitation costs, and maximizing the expected serviceability index by the “serviceability player,” who focuses on ensuring absorptive resilience. The MOGM-based approach is applied to a benchmark WDS, resulting in two Nash equilibria rehabilitation strategies with costs ranging from $9.4M to $9.6M and serviceability indices from 0.9047 to 0.9166. The proposed approach is compared to a conventional multiobjective method, which assumes perfect collaboration among conflicting goals to achieve optimal solutions. This conventional method produced five nondominated rehabilitation strategies with costs spanning from $8.5M to $9.9M and serviceability indices ranging from 0.8713 to 0.9591, complicating decision-making due to the broad array of options. This research introduced a strategic game theory-based framework for proactive pipeline rehabilitation, enhancing WDS absorptive resilience and cost-effectiveness and offering decision-makers a simplified selection process through two Nash equilibria rehabilitation strategies that balance costs and absorptive resilience.