Revisiting the Resilience Index for Water Distribution Networks

Abstract

Water distribution systems (WDSs) are social infrastructures providing drinking water and must be capable of constant water supply while maintaining an appropriate water pressure. Hence, it is important to quantitatively evaluate the supply capacity of a WDS for design and operation purposes. As part of such efforts, several resilience indexes have been developed based on the energy flows within a network. Accurate estimation of a minimum required head at the demand node is critical for properly calculating the resilience indexes. This study proposes a novel approach of estimating the minimum required head, which considers the flow direction in pipes and the hydraulic gradient within a network. The proposed approach has been implemented and tested for six hypothetical grid-type networks that reflect various topographical characteristics. The application results revealed that the conventional resilience indexes are significantly affected by the nodal elevation and are generally overestimated due to incorrect calculation of the minimum required nodal head.