Modeling interdependent water uses at the regional scale to engage stakeholders and enhance resilience in Central Arizona

As cities and agricultural areas face water challenges associated with climate change, it is important to develop a better understanding of how human and natural systems will respond at the scales at which those changes will occur. This requires analytical tools to systematically explore regional contexts where multiple interdependent water, agricultural, and urban infrastructures interact. Toward this end, we develop and analyze a stylized model of a regional-scale system in the Southwestern U.S. The system is comprised of the Phoenix and Tuscon metropolitan areas and surrounding agricultural districts within the Central Arizona Project service domain and the water delivery infrastructure that connects these areas to the Colorado River basin. We use the model to analyze the impacts of changes in runoff in the upper Colorado River basin and the Salt, Verde, and Agua Fria basins on water supplies in the Central Arizona Project service area. Specifically, we explore how conceptualizing the Phoenix and Tuscon metropolitan areas and surrounding agricultural districts as an integrated system of urban, agricultural, and conjunctive ground and surface water management infrastructures can lead to strategies to meet water demand while maintaining groundwater neutrality.