Asset-Based Assessment of Resiliency in Water Distribution Networks

This paper proposes an Asset-Based methodology to measure the resilience of Water Distribution Networks (WDNs). In the proposed approach, based on impacts of failure of every single asset on the performance of the system, specific degree of criticality in the estimation of a WDN resiliency can be evaluated. This criticality may be extended into three resiliency dimensions; technical, economic and social. Five indexes namely; Hydraulic Critically Index, Regret Cost (revenue losses associated with water sales), Graduality (speed of outage progression from a failure), Recovery Rate (rate of system performance recovery to a normal state) and Water Outage Time (unsatisfactory duration of system performance) are introduced here to address these resiliency dimensions. Several MATLAB suit codes are written and incorporated into the EPANET software to assess the proposed indexes for a real case study suffering from high rate of pipe failure. The results show that an asset usually has common behaviour in both of technical and economic resiliency aspects. Furthermore, system performance in case of a failure can decrease faster than the rate of recovering to a normal state. In addition, the new indexes can confidently assess the weak points, strength points and finally the asset’s role in the system’s resiliency while quantifying internal technical capacities. In brief, addressing resilience assessment within the proposed approach can help in targeting high-priority maintenance needs of WDNs and mobilize minimizing the consequences of each failure event.