Performance-based resilience assessment in integrated water systems: challenges and opportunities

• Review performance-based resilience assessment approaches in water systems. • Identify eight challenges for applying performance-based approach in integrated water systems. • Develop a unified approach that enables resilience intercomparison among water subsystems. • Design application scenarios for using resilience to enhance integrated water system management. The concept of resilience has been increasingly applied in water systems management and planning. It has been assessed through a ‘performance-based’ approach, which derives resilience metrics from dynamic system behaviour under pressure. However, the application of this approach may face great challenges when applied to integrated water systems, including the complexities in physical processes, diverse management objectives, and siloed practices across subsystems. To assess its feasibility, we review the key elements of the performance-based resilience assessment, including performance indicators, thresholds, and resilience metrics, across urban, agricultural, and natural water subsystems. Eight challenges are identified, primarily focused on deriving consistent results across subsystems and interpreting assessment for actionable management. To address these challenges, a resilience assessment framework for integrated water systems is proposed. This framework applies unified resilience assessment approaches across subsystems to enable intercomparison and synthesises short- and long-term behavioural characteristics through a bottom-up method. Stakeholder engagement is emphasised to validate and iteratively refine assessments, enhancing the effectiveness and applicability. To demonstrate its utility, three potential application scenarios are conceptually designed to (1) quantify co-benefits and trade-offs on a unified scale, (2) evaluate the cost-effectiveness of planning decisions, and (3) guide regional planning based on catchment characteristics. Future research could test these scenarios and generate evidence to enhance decision-making for resilient integrated water systems.