This project will study decision-making for water resources management in anticipation of climate change in northern Mexico as a case study for the broader arid and semiarid southwestern North America. The goal of the project is to determine whether water resources systems modeling, developed within a participatory framework, can contribute to the building of management strategies in a context of water scarcity, conflicting water uses and highly variable and changing climate conditions. Local stakeholders will be involved in guiding the design of supply- and demand-side management strategies and selection of climate change scenarios using state-of-the-art engineering tools. These tools include a water resources systems framework, a spatially-explicit hydrologic model, the use of forecasted climate scenarios under 21st century climate change, and observations obtained from field and satellite sensors. The participatory modeling approach will be conducted through a series of interactive workshops, carefully designed to encourage substantive participation from a broad range of stakeholders, including representatives from federal and local government agencies, water use sectors, non-governmental organizations, and academics. The work will evaluate the sustainable outcomes emerging from the climate change scenarios and the potential adaptations that can be implemented in the decision-making process. The proposed work combines engineering research with social and behavioral sciences for the purpose of evaluating sustainable water management outcomes in a semiarid region in a developing country. Three doctoral level students will be engaged as well as undergraduate students for short-term research experiences. A focus on recruiting Hispanic students (with language skills) will facilitate interactions with local decision makers, regional stakeholders and the general public. The project team will also work with several local universities in Sonora to develop an effective participatory modeling program. The target is for the results of this project to have an impact on water decision-making under climate change in the study area and to provide a case study for replication in other data-sparse, semiarid regions.