Integrated redundancy measure for the analysis of water distribution network

The directional nature and complex interconnections of a water distribution network (WDN) layout make it challenging to analyze its performance. The interplay of nodes and links in a WDN creates inherent redundancy in the network layout, which should be accounted for in performance assessment. Previous studies mainly focussed on the hydraulic nature of WDN redundancy. In this respect, to understand the importance of topological configuration on the performance of WDN, it is imperative to have proper measures to provide a comprehensive picture of the WDN redundancy. This study presents a new redundancy measure that integrates topological and hydraulic redundancies. Complex network theory (CNT) offers an option to gain insight into the topological behavior of a WDN. Nodal indegree, a directional CNT metric based on connections incident on a node, can provide information about the redundancy of various configurations of WDNs. Hydraulic nodal redundancy index is based on entropy value of demand fraction determined based on incident pipes/links. Our investigations indicate a high correlation between hydraulic redundancy and indegree ranging from 0.80 to 0.99, implying that nodal indegree is an effective CNT metric. The effectiveness of the proposed integrated redundancy measure is demonstrated by application to WDNs having different configurations (tree, looped, and mixed). The study gives new insight into the overall redundant nature of WDNs. The integrated redundancy measure is found to be better for evaluating existing WDNs and analyzing new network layouts at the planning and design stage.