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Lehner B.,McGill University | Liermann C.R.,University of Washington | Revenga C.,Nature Conservancy | Voromsmarty C.,City University of New York | And 11 more authors.
Frontiers in Ecology and the Environment | Year: 2011

Despite the recognized importance of reservoirs and dams, global datasets describing their characteristics and geographical distribution are largely incomplete. To enable advanced assessments of the role and effects of dams within the global river network and to support strategies for mitigating ecohydrological and socioeconomic costs, we introduce here the spatially explicit and hydrologically linked Global Reservoir and Dam database (GRanD). As of early 2011, GRanD contains information regarding 6862 dams and their associated reservoirs, with a total storage capacity of 6197 km 3. On the basis of these records, we estimate that about 16.7 million reservoirs larger than 0.01 ha - with a combined storage capacity of approximately 8070 km 3 - may exist worldwide, increasing Earth's terrestrial surface water area by more than 305 000 km 2. We find that 575 900 river kilometers, or 7.6% of the world's rivers with average flows above 1 cubic meter per second (m 3 s -1), are affected by a cumulative upstream reservoir capacity that exceeds 2% of their annual flow; the impact is highest for large rivers with average flows above 1000 m 3 s -1, of which 46.7% are affected. Finally, a sensitivity analysis suggests that smaller reservoirs have substantial impacts on the spatial extent of flow alterations despite their minor role in total reservoir capacity. © The Ecological Society of America.

Pahl-Wostl C.,University of Osnabrück | Arthington A.,Griffith University | Bogardi J.,Global Water System Project | Bunn S.E.,Griffith University | And 12 more authors.
Current Opinion in Environmental Sustainability | Year: 2013

Human water security is often achieved with little consideration of environmental consequences and, even when these are acknowledged, the trade-offs between human and environmental water needs are increasing in frequency and amplitude on the increase. The environmental flows concept has continued to evolve in response to these challenges. However, the field is characterized by a limited transferability of insights, due to the prevalence of specific case-study analyses and a lack of research on the governance of environmental flows. Building on recent advances in environmental flow science, water governance and management, we identify a clear need for a more systematic approach to the determination of environmental flow requirements (EFRs) on both the natural and social science fronts and, in particular, on the interaction between social/political and environmental systems. We suggest a framework that details as to how these advances and interactions can be achieved. The framework supports scientific analysis and practical implementation of EFRs involving systematic compilation, sharing and evaluation of experiences from different riverine ecosystems and governance systems around the globe. The concept of ecosystem services is introduced into the framework to raise awareness for the importance of ecosystem functions for the resilience of social-ecological systems, to support negotiation of trade-offs and development of strategies for adaptive implementation. Experience in implementation of environmental flow policies reveals the need for an engaged, transdisciplinary research approach where research is closely linked to implementation initiatives on the ground. We advocate that this is more effective at building the foundations for sustainable water management. © 2013 Elsevier B.V.

Pahl-Wostl C.,University of Osnabrück | Vorosmarty C.,City College of New York | Bhaduri A.,Global Water System Project | Bogardi J.,Global Water System Project | And 2 more authors.
Current Opinion in Environmental Sustainability | Year: 2013

Over a decade of global water research has provided clear evidence on the global dimension of the water challenge and the role of humans as a chief force shaping the global water cycle. Mounting evidence suggests no reversals in major trends and an expectation of intensified and pandemic water problems. Research in the past has emphasized the identification of problems more than the identification of solutions. A clear shift in emphasis towards solutions-oriented approaches is required. The next decade of research should be directed towards motivating a transition from knowledge-to-concrete action, and to find solutions through the co-production of knowledge involving scientists and stakeholders. This paper summarizes a blueprint for a Sustainable Water Future initiative, arguing for the necessity of a strong water programme in global change research. We provide specific suggestions on forming a strategic partnership of scientists, public stakeholders, decision-makers and the private sector to implement a reality-based, multi-perspective, and multi-scale knowledge-to-action water agenda. © 2013 Elsevier B.V.

Bogardi J.J.,Global Water System Project | Dudgeon D.,University of Hong Kong | Lawford R.,Morgan State University | Flinkerbusch E.,Global Water System Project | And 4 more authors.
Current Opinion in Environmental Sustainability | Year: 2012

Sustainability, equitable allocation and protection of water resources must occur within the framework of integrated management and water governance, but its implementation is problematic. Ongoing global climate change, increasing population, urbanization, and aspirations for better living standards present a challenge to the planetary sustainability. While water use at global scale currently seems to be within its planetary boundary, shortages prevail in several water-scarce and overpopulated regions, and are projected to increase. Furthermore large-scale impoverishment of aquatic biodiversity, ecosystem degradation and reductions in water quality are unaddressed 'side effects' in areas where water can be secured for human and economic uses. As the world prepares for Rio+20, challenges to the sustainability of global water security should be scrutinized. Of particular concern is the likelihood that the water-related Millennium Development Goals (MDGs) targets may not be achievable due to lack of funding commitments, and a failure of delivery mechanisms including water governance. Constraints on water availability and reductions in water quality jeopardize secure access to this resource for all legitimate stakeholders, including aquatic and terrestrial ecosystems. Water connects several socio-ecological, economic and geophysical systems at multiple scales and hence constitutes a 'global water system'. This should be considered both in technical interventions and in governance frameworks. Humans have been changing the global water system in globally significant ways since the industrial revolution, yet without adequate knowledge of the system and its response to change; and without sufficient understanding of how to govern the system at local and global scales. Water security in the 21st century will require better linkage of science and policy, as well as innovative and cross-sectoral initiatives, adaptive management and polycentric governance models that involve all stakeholders. Consensus solutions will need to be achieved by evidence-based mediation, rather than following untested 'panaceas', so as to ensure equitable and sustainable global water use. © 2012 Elsevier B.V.

Kistemann T.,University of Bonn | Hoser C.,University of Bonn | Voigt H.,Global Water System Project
Current Opinion in Environmental Sustainability | Year: 2011

From elementary, illustrative description, medical cartography developed into a tool for analytical research already 150 years ago. Water has always played an outstanding role for health mapping. Temporal aspects and the perception of the interaction of multidimensional drivers necessarily pushed mapping of water and health forward into the field of spatial statistics. In recent decades, both the availability of computer processing capacity and an abundance of data becoming available from different sensors triggered the development of powerful Geographic Information Systems (GIS). This is especially the case when a ubiquitous element like water, which affects health in manifold ways, is the focus of interest. This opens up challenging demands and exciting tasks for experts, but may also include obstacles for less developed countries, where people are suffering from water-related health problems on an everyday basis. This paper provides a short review of the current state of the art and illustrates the utilisation and perspectives of GIS for water-related health research. © 2011 Elsevier B.V.

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