Even the best-maintained water distribution network (WDN) might suffer pipe bursts
occasionally, and the utility company must reconstruct the damaged sections of the
system. The affected area must be segregated by closing the corresponding isolation
valves; as a result, the required amount of drinking water might not be available.
This paper explores the behaviour and topology of segments, especially their criticality
from the viewpoint of the whole system. A novel, objective, dimensionless, segment-based
quantity is proposed to evaluate the vulnerability of both the segments and the whole
WDN against a single, incidental pipe break, computed as the product of the probability
of failure within the segment and the amount of unserved consumption. 27 comprehensive
real-life WDNs have been examined by means of the new metric and with the help of
complex network theory, exploiting the concept of the degree distribution and topology-based
structural properties (e.g. network diameter, clustering coefficient). It was found
that metrics based purely on topology suggest different network behaviour as vulnerability
analysis, which also includes the hydraulics. The investigation of the global network
vulnerabilities has revealed several critically exposed systems, and the local distributions
unveiled new properties of WDNs in the case of a random pipe break.
