TARGET RESILIENCE INDEX FOR WATER DISTRIBUTION NETWORKS
Keywords:Resilience index, Water distribution networks, Free residual chlorine, Reliability
Urban water distribution networks (WDNs) require reliability to provide adequate pressure and good water quality. One way to assess WDNs’ reliability is through a resilience index. Typically, a resilience index is an index of how the surplus of the required variables such as energy or chlorine mass compares to a system input of such variables. In this paper, we modified the resilience index to include a target value of pressure (Target Hydraulic Resilience Index, THRI) and free residual chlorine concentration (Target Chlorine Resilience Index, TCRI). We applied the THRI and TCRI to a district metering area. The results showed that both RIs clearly explain the state of the reliability of the WDNs compared to the target values. The impact of water loss on each RI is that less water loss resulted in a higher THRI while less water loss gave a lower TCRI. The THRI and TCRI can also be presented in both time and space. Hence, we can assess the deficits of temporal and spatial resilience indices from the targets. Therefore, they can be used for pressure and chlorine management to improve the WDNs’ reliability.