Sustainability science studies the causes, pathways and impacts of complex development problems that result from the interaction of natural and social forces. Water availability in and basins with rapidly growing populations presents a perfect example of a development problem that needs sustainability science to provide the scientific underpinnings for integrated management of the basin. The author (1) introduces the concept of sustainability science, (2) applies the concept to integrated water basin management, and (3) illustrates the use of sustainability science in the management of the and Rio Grande basin on the border between Mexico and the United States. (C) 2006 Elsevier Ltd. All rights reserved.