Since the second half of the twentieth century, three principal interrelated drivers have posed major management and policy challenges for water managers left unaddressed, these tend to exacerbate preexisting socioeconomic vulnerabilities and indeed cause new ones. These drivers are: 1) population growth 2) economic development and more recently, 3) global climate change. Water management must increasingly address the complexity of these drivers and their effects at different spatial and temporal scales. In the past decades, integrated water resources management, and its offshoot, integrated river basin management, have been proposed and, in some locations, implemented to address these challenges. However, we demonstrate here that additional complementary approaches are required: those that give greater importance to social, ecological, and hydroclimatic interactions to the dual risk and resource (destructive and productive) characteristics of water and to the enhancement of river basin resilience through adaptive management. We do this through examination of case evidence from arid and semiarid Chile, Argentina, Peru, northeast Brazil, northwest Mexico, and southwest United States.
