A vertically integrated assessment of climate impacts on water supply in Arizona

The climate of the Southwest U.S. is both highly variable and non-stationary, yet many water management decisions and actions continue to be based on the concept of long-term climate stationarity. Vertical assessments of the climate impacts of this variable, non-stationary regional climate system are being carried out under the Climate Assessment for the Southwest Project (CLIMAS) at University of Arizona. These assessments are designed to evaluate the region's sensitivity, vulnerability, and coping capacity (buffering), to fill in gaps in understanding of climatic and hydrologic variability including forecast skill assessment, and to communicate new and existing knowledge to stakeholders.

Water is one of the central themes of CLIMAS assessments, and a major integrated effort within CLIMAS is broadly focused on the impacts of both seasonal to interannual and decade to century scale climate variability on water resources. This multi-faceted investigation is framed within the legal, institutional, and organizational structure of water supply management. A major focus of this particular assessment has been the sensitivity and vulnerability of urban water systems to specific drought scenarios as well as water providers' perceived needs for and usage of climate information. Identifying stakeholder vulnerability and needs influences, in turn, the natural science research agenda. Currently, natural science research is addressing forecast skill, natural variability of the hydrology and climate of the region, and seasonal precipitation dynamics. The ultimate goal of this effort is to better understand and predict climate regimes at multiple temporal and spatial scales, so as to increase the capacity of water managers to cope with both climate stresses and opportunities.