Financially sustainable management strategies for urban wastewater collection infrastructure - Implementation of a system dynamics model

This study develops and demonstrates a wastewater system dynamics model as a decision support tool that can assist utility managers to ensure financial sustainability while maintaining customer expectations for service performance. To achieve implementation of the model, a demonstration case study is developed using data from a medium-sized city in Ontario, Canada, having a large backlog of deteriorated wastewater pipes. Specific outcomes for this study include: (1) presentation of a methodology to parameterize the demonstration model using available utility data; (2) demonstration of the significance of interrelationships between system variables on a system's performance indicators such as total life-cycle costs, Internal Condition Grade of pipes, sewage fees; and (3) exploration of alternative financially sustainable management strategies for operating a wastewater network that involve the trade-offs between maintaining a strict 'zero fund balance' with no borrowing, versus issuing debt to accelerate a capital works program. Results indicate that a financing strategy involving borrowing can minimize the total life-cycle cost while maximizing the service performance level of the network. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.