Capacity Reliability And Rehabilitation OfDeteriorated Water Distribution Systems

This paper describes an approach to assessing and economically improving the condition of deteriorating water distribution infrastructure. The approach uses a first order reliability method (FORM) to determine the system capacity reliability where capacity reliability is defined as the probability that the system is able to supply the consumer with the specified quantity of potable water at or above a prescribed minimum pressure. The method is capable of recognising uncertainties in both the nodal demands and the pipe capacities. The proposed probabilistic model also provides the facility for computing sensitivity of the reliability to changes in the network parameters. The reliability sensitivity measures are effectively used to prioritize the resource allocation in making rehabilitation decisions to improve the level of service. The performance of the model is illustrated through the application to an example network.