A probabilistic framework to assess resilience in regional water systems - exploring the impact of circular water strategies

Contrary to the ‘make-use-dispose’ linearity seen in conventional resource management, circular economy design principles have been proposed as an  alternative that reduces waste and promotes efficiency. These principles find use in water as well, offering an alternative against centralized water systems planning and management. Despite the intrinsic links between circularity and resilience, few studies have advanced the identification and discussion of linkage beyond a theoretical or conceptual level. Moreover, few studies have estimated resilience with a probabilistic approach to include the inherent future uncertainty located simultaneously at source and demand level. In this study, a probabilistic framework to assess resilience for regional systems across multiple domains (drinking water, wastewater and drainage) is presented. The framework is based on stress-testing using an urban water cycle model, paired with reliability-based Key Performance Indicators (KPIs) that describe system resilience for each domain and for several different stress-testing factors (stressors). For its practical implementation, the framework is then applied to the provincial case study of Delfland, the Netherlands, where different circular water strategies are evaluated in terms of their overall resilience, (a.) firstly deterministically to explore the impact of individual stressors, and (b.) probabilistically to evaluate system performance against future uncertainty. The results quantitatively demonstrate that circular water options lead to water systems of increased resilience. The more circular dimensions are addressed through interventions and management strategies, the more robust resilience profiles become across different urban water cycle domains, thus securing regional water systems against future uncertainty.