For two decades, the southwestern region of the United States has been in the grips of one of the most severe droughts of the last 1,200 years. It is a grave challenge to the most basic of rights: access to water, basic food production, and the habitability of cities. Policymakers across the country have needed to be bold and varied in their quest to secure water and draw upon the lessons of the past.
The causes of the multidecadal drought, often referred to as a ‘megadrought’, can be largely attributed to lower rainfall. The deficit is driven by natural variability in rainfall patterns, ocean dynamics in the tropical Pacific, and exceptionally warm temperatures.
Collectively, these phenomena have dried out soil, reduced stream flow, and created snow droughts. It has prompted a major decline in surface and groundwater resources, economic losses, ecosystem disruptions, and an increased risk of wildfires. From January 2020 to August 2021, six southwestern states (Arizona, California, Colorado, Nevada, New Mexico, and Utah) experienced the lowest total precipitation and the third-highest daily average temperatures recorded since 1895. The weather pattern continued into 2022 and prompted governors in each of the six states to issue drought emergency declarations. The federal government issued an unprecedented water shortage declaration, ordering water restrictions along the Colorado River, a major source of water for agriculture and cities in the region. The frequency and intensity of such droughts, and their cross-cutting and compound effects, are projected to increase as a result of climate change. In response, policymakers and water agencies across the southwest have developed new water management strategies to enhance local drought resilience. At the local level, such efforts are frequently nested within a complex inter- and intrastate institutional framework in which surface water supplies (as opposed to groundwater) are governed using an ‘appropriative’ system of water rights. Administered by state-level agencies, the allocation of finite surface water flows is complicated by the diversity of competing stakeholders - social, economic, and environmental - intensifying discussions in dry times. Water management decisions at the local level may be hindered by state-level water restrictions enacted ad hoc, intergovernmental treaties concerning transboundary water resources, and environmental regulations.
