A Trade-Off between Supply-Side and Demand-Side Management for Urban Water Resources

Urban water management specifies both supply-side and demand-side strategies to balance water supply and demands for social and environmental systems. As the sustainability of water resources depends on the dynamic interactions among the consumers and the policy makers of the water system, an optimal adaptive water management approach can be used to update utility decisions based on the feedback among these systems and may enable a more efficient use of resources. Adaptive demand-side management strategies, such as regulating water for outdoor use, can be designed with increasing restrictions corresponding to the depletion of reservoirs. Similarly, adaptive supply-side strategies can be designed to supplement supply by increasing the volume of water that is transferred among basins when reservoirs levels drop. In this study, a Complex Adaptive Systems (CAS) framework is used to simulate the adaptive behaviors of consumers, the adaptive decisions of the water utility, and an engineering model of the water supply infrastructure. The CAS framework is coupled with an optimization methodology to evaluate a combination of supply-side and demand-side adaptive water management strategies in achieving the utilities goal of minimizing management costs. The methodology is applied to an illustrative case study of an urban water supply system to explore trade-off relationship between optimal adaptive water management strategies.