Sensitivity of Urban Water Resources in Phoenix, Tucson, and Sierra Vista, Arizona, to Severe Drought

Water scarcity is an ever-present fact of life in the arid and increasingly urbanized Southwest. Yet even with the considerable effort expended on drought-proofing urban areas through infrastructure and policy development, droughts of magnitudes found in historical records of the past 100 yr continue to threaten the region’s cities. Results of an analysis of the sensitivity of 3 urban areas in Arizona to selected drought scenarios suggest that severe droughts or 1, 5, and 10 yr duration would severely stress existing water supply/demand budgets. The results of the analysis suggest that very considerable conservation efforts would be required to bring demand into balance with existing supply. This article reports on the results of analysis of the sensitivity of urban water systems in the Phoenix and Tucson metropolitan areas as well as in the Sierra Vista subwatershed, which includes the rapidly growing city of Sierra Vista and the adjacent Fort Huachuca Army Base.