Graduation Year


Document Type




Degree Name

MS in Civil Engineering (M.S.C.E.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Qiong Zhang, Ph.D.

Committee Member

Daniel Simkins, Ph.D.

Committee Member

Mahmood Nachabe , Ph.D.


Criticality, Failure, Isolation valves, Topology, Vulnerability


To ensure adequate performance of water distribution networks, utilities must identify critical segments within the network that will adversely affect users when failures occur. Currently, time consuming hydraulic simulations are used for such criticality analyses. A method can be of great benefit for utilities if it can easily evaluate the criticality of water distribution network segments. This research applies topology-based methods for the preliminary screening of critical segments. This study evaluated the connectivity between sources and each demand segment in water distribution networks using minimum cut-sets. Through topological analysis, the minimum cut -set between the source node and each demand segment in the segment-vale representation of a given water distribution network was identified. The frequency of a segment appearing in all minimum cut-sets for the network was then calculated. The segments were ranked based on the frequency and the segments with high frequency were identified as critical segments in the network. Hydraulic simulations were used to evaluate the topology-based method. Specifically, the system demand shortfall for each segment isolation in the water distribution networks was calculated and used to identify critical segments. The critical segments identified based on the minimum cut-set were compared with those identified based on the system demand shortfall to determine the degree of consistency between the two approaches. The critical segments identified through topological analysis had a strong correlation with those identified through hydraulic simulations. Therefore, topological analysis can be used as a simple method for preliminary screening of critical segments.