Agent-Based Modeling for Simulating the Decentralization of Urban Water Infrastructure Systems

Abstract

Urban water infrastructure systems, including drinking water, wastewater, and stormwater, should be designed to efficiently use water and energy resources. Current design paradigms typically neglect the interconnection among these systems; water, wastewater, and stormwater are treated at centralized facilities, and water services are distributed within a municipality through pipe networks. Due to water shortages and limited budgets, water utilities may encourage individual households to adopt water reuse, water conservation, and lot-level stormwater treatment technologies, which may produce a decentralized water service system. Transitioning from a centralized to a decentralized approach within urban water infrastructure systems will change demands and affect the performance of the existing infrastructure and the use of energy and water resources. To enable exploration of the impacts of decentralization on the sustainability and resilience of urban water infrastructure systems, a Complex Adaptive Systems (CAS) approach is developed here. This modeling framework characterizes the various feedback loops, dynamic interactions, and emergent phenomena that result from the interactions of decentralized and centralized components of the water infrastructure systems. Specifically, rainwater harvesting is explored as a decentralization technology, which reduces stormwater service demands and drinking water demands on the centralized infrastructure systems. An agent-based modeling approach is used to simulate technology adoption of individual consumers in response to water shortages and is coupled with water and energy utilization models. The framework provides insight to the interconnections and interactions between the consumers, water supply and delivery system and the effect of these interactions on water and energy use and sustainability; infrastructure system design; and system resilience, as a system transitions from a centralized to a decentralized layout.