Complex Adaptive Systems Framework to Assess Supply-Side and Demand-Side Management for Urban Water Resources

The availability of water resources in many urbanizing areas is the emergent property of the adaptive interactions among consumers, policy, and the hydrologic cycle. As water availability becomes more stressed, public officials often implement restrictions on water use, such as bans on outdoor watering. Consumers are influenced by policy and the choices of other consumers to select water-conservation technologies and practices, which aggregate as the demand on available water resources. Policy and behavior choices affect the availability of water for future use as reservoirs are depleted or filled. This research posited urban water supply as a complex adaptive system (CAS) by coupling a stochastic consumer demand model and a water supply model within an agent-based modeling (ABM) framework. Public officials were simulated as agents to choose water conservation strategies and interbasin transfer strategies, and consumers were simulated as agents, influenced by various conservation-based programs to select water conservation technologies and behaviors, and correspondingly update their individual demand models. A water supply reservoir was simulated to receive rainfall from the contributing watershed and to supply the demands of consumer agents. The ABM framework was applied to an illustrative urban case study. A set of scenarios was developed to represent moderate and strong water conservation strategies, and was simulated for a long-term precipitation record to evaluate the sustainability of water conservation practices.