Comparing Performance Indicators for Assessing and Building Resilient Water Distribution Systems

Abstract

Water distribution systems (WDSs) are critical infrastructures that need to be resilient to cope with and quickly recover from exceptional conditions in an uncertain and challenging future. To build resilience in the design of WDSs, it is essential to explore indicators that can effectively quantify the level of system resilience. On the basis of the optimization of rehabilitation designs of three benchmark WDSs, four resilience related indicators are investigated, i.e., Todini’s index, which is a surrogate and indirect performance indicator, and three direct performance indicators—failure duration, failure magnitude, and a severity-based resilience index. These indicators are widely used in the literature yet have not been comprehensively examined and compared. Results show that strong correlations exist between the four resilience-related indicators, indicating that optimization using any one indicator is likely to improve system resilience measured by other indicators. Nevertheless, they have distinctive advantages and disadvantages. In particular, the severity-based resilience index is effective in identifying nodes susceptible to the occurrence of failures and slow in recovery. Todini’s index can be assessed without the need to set up failure scenarios, which is an advantage compared to the other three resilience indicators; however, its correlations with direct resilience indicators are weaker in WDSs with tanks.