Externalities on urban traffic due to water systems structural and operational maintenance activities

Limited budget forces infrastructure managers to identify levels of priorities in maintaining systems in order to face the increasing level of deterioration due to aging. Models to select critical components of drinking water systems have been developed by DISTART of Bologna University. The aim is to support decision makers in planning operational maintenance of the network to achieve the maximum benefit at lower cost (Advanced Asset Management). Being drinking water pipes under urban streets, while computing the indirect social costs due to water supply systems failures, both the costs due to the service not delivered and the costs due to the impacts on streets because of maintenance works, like delays on traffic, should be computed. The method presented consists both on evaluating the vulnerability of drinking water systems and of the urban road network as independent systems, and on computing the global vulnerability of the interaction of the two systems by aggregating results on a GIS platform. The approach allows water manager to optimise the use of maintenance resources, road manager to prevent traffic disturbance and evaluate possible franchise tax, and promote a joined management prospective.