Water is an essential building block of the Earth system and critical to human prosperity. At the same time, humans are rapidly embedding themselves into the basic character of the water cycle without full knowledge of the consequences. Major sources of water system change include mismanagement and overuse, river flow distortion, pollution, watershed disturbance, invasive species, and greenhouse warming. Defining the collective significance of such change constitutes a major challenge for the Earth and social sciences alike. This project will advance current understanding of the ways in which humans control, degrade or enhance water-related ecosystem services, and in turn impact the global economic system and aquatic biodiversity. These goals will be addressed through an integrated, interdisciplinary study of human-water interactions that includes modeling, data integration, and assessment tools as well as synthesis across water resource management, biology, and environmental economics perspectives. Model projections will be used to extend recent trends into the future, and assess the degree to which alternative management strategies can lead to more sustainable futures over a 100-year time horizon. The interdisciplinary aspects of the many forces shaping modern river systems provide a rich intellectual environment for collaboration, and lessons learned through this project's cross-disciplinary approaches constitute an important byproduct of the work.
Given the central role of water in our environment and human well-being, results from this project will have immediate value to efforts to manage freshwater resources. Beyond its scientific value, a synthetic understanding of the state of the rivers systems--the single largest renewable water supply serving humankind--is of strategic importance to the public policy sector, given a growing sense of urgency regarding water as an international security issue. The benefits of such synthesis will inform global social and environmental management challenges: coping with climate extremes; preserving ecosystem services and biodiversity; food and energy security; economic competitiveness; and, protecting human health. This project will have lasting benefits by targeting policy-relevant science, educating the next generation of students in strategic resource assessment, and informing the citizenry about major environmental challenges and solutions for the future.