Exploratory Analysis of Surrogate Metrics to Assess the Resilience of Water Distribution Networks

Abstract

This study compares and discusses the adequacy of surrogate resilience metrics proposed in the literature for resilience assessment of drinking water systems concerning demand increase and network redundancy. A sensitivity analysis is carried out for increasing flow rates using a conceptual case study with different layouts and demand scenarios, selecting several metrics to assess the resilience of two real network areas. Resilience metrics based on surplus energy are sensitive to network layout and demand scenarios. The network resilience index considers hydraulic reliability and network diameter uniformity. In contrast, the weighted resilience index also considers the network topology and gives importance to pipes with higher flow rates. Entropy‐based resilience metrics mainly rely on the network flows' uniformity and are sensitive to pipe redundancy. The entropy metric most adequate to assess the hydraulic capacity is the diameter‐sensitive flow entropy, since it is sensitive to the velocity inside the pipes. Topology metrics cannot assess the hydraulic capacity though evaluate the system redundancy (meshed‐ness coefficient), robustness (central‐point dominance) and water transportation efficiency (average‐path length). Surrogate resilience metrics do not assess the system performance during a failure. They indicate systems which are better prepared to overcome failure events and increased demand events, providing vital information to drinking water systems management.This article is protected by copyright. All rights reserved.

Integrating Uncertainty in Performance Assessment of Water Distribution Networks by Scenario Building

“…The proposed methodology provides a scenario evolution of hydraulic results (i.e., actual demand, pressure head, flow rate, and head loss) through time that can be used to calculate a wide range of performance assessment metrics. Three metrics associated with the hydraulic resilience of WDN were used to illustrate the use of the scenario-building approach, namely, (i) the network resilience index (NRI) [23,24] to ensure a flexible service, particularly to increase water demand; (ii) the minimum pressure index [25][26][27]; and (iii) the real water loss performance indicator (PI) [28]. These metrics are presented in Table 2.…”

“…approach, namely, (i) the network resilience index (NRI) [23,24] to ensure a flexible service, particularly to increase water demand; (ii) the minimum pressure index [25][26][27]; and (iii) the real water loss performance indicator (PI) [28]. These metrics are presented in Table 2.…”

“…The network resilience index is used to evaluate the service flexibility for eventual increases in water demand. Its values range between 0 and 1, where values near 0 have small service flexibility to an increase in demands and values close to 1 correspond to systems with good service flexibility [24]. The minimum pressure index, used to assess the service reliability, has reference values similar to those used in [26] (see Table 2).…”