Demand Constructs for Risk Analysis

Forcing the assigned demands on a system that lost a major portion of its supply may produce erroneous results such as unrealistically low negative pressures. A more realistic model would allow for the partial reduction of delivered water when the catastrophically-impaired network can no longer deliver the assigned demands. A number of auxiliary programs were developed to replace conventional system demands with various alternative demand constructs. These alternative demand constructs were then used to investigate the impact of catastrophic failure on model performance. Five different demand constructs are presented, applied to a water system model and subjected to catastrophic failure.