A System Dynamics Approach: For Modeling Natural Infrastructure Aging in Sustainable Urban Water Supply Systems
Keywords:
Sustainable Urban Water System, System Dynamics model, Infrastructure Aging, Installed Network Health ConditionsAbstract
The provision of safe and reliable drinking water is fundamental to urban quality of life and sustainable economic development. However, aging water-supply infrastructure can progressively increase leakage, reduce service reliability, and intensify long-term asset-management pressures. This study develops a System Dynamics model that explicitly represents the natural aging of urban water-distribution infrastructure and evaluates its implications over a 50-year planning horizon. The model represents pipe cohorts by age and quantifies leakage fraction, serviceable life, and the proportion of infrastructure exceeding a 50-year service-life threshold. Two scenarios are evaluated: a newly developed network in which the 1,000-km network initially occupies the youngest age cohort, and a mature network in which the same total length is distributed equally among four age cohorts below 50 years. The simulations show that the Base Scenario leakage fraction increases from 0.10 to 0.70, whereas Scenario 1 increases from 0.35 to 0.81 by Year 50. Over the same horizon, the serviceable-life indicator increases from 6 to 42 years in the Base Scenario and from 25 to 46.5 years in Scenario 1. Despite the higher serviceable-life indicator in Scenario 1 at Year 50, its over-aged network fraction reaches 78%, compared with 54% in the Base Scenario. The results demonstrate that aggregate serviceable-life measures can mask the physical deterioration of aging infrastructure and should therefore be complemented by age-based condition and leakage indicators. The study provides a quantitative systems-thinking framework for long-term infrastructure planning and supports proactive asset replacement, condition-based rehabilitation, and evidence-based investment decisions.
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