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Rockström, J.; Falkenmark, M.; Allan, T.; Folke, C.; Gordon, L.; Jägerskog, A.; Kummu, M.; Lannerstad, M.; Meybeck, M.; Molden, D.; Postel, S.; Savenije, H. H. G.; Svedin, U.; Turton, A.; Varis, O.
The human influence on the global hydrological cycle is now the dominant force behind changes in water resources across the world and in regulating the resilience of the Earth system
. The rise in human pressures on global freshwater resources is in par with other anthropogenic changes in the Earth system (from climate to ecosystem change), which has prompted science to suggest that humanity has entered a new geological epoch, the Anthropocene. This paper focuses on the critical role of water for resilience of social-ecological systems across scales, by avoiding major regime shifts away from stable environmental conditions, and in safeguarding life-support systems for human wellbeing. It highlights the dramatic increase of water crowding: near-future challenges for global water security and expansion of food production in competition with carbon sequestration and biofuel production. It addresses the human alterations of rainfall stability, due to both land-use changes and climate change, the ongoing overuse of blue water, reflected in river depletion, expanding river basin closure, groundwater overexploitation and water pollution risks. The rising water turbulence in the Anthropocene changes the water research and policy agenda, from a water-resource efficiency to a water resilience focus. This includes integrated land and water stewardship to sustain wetness-dependent ecological functions at the landscape scale and a stronger emphasis on green water management for ecosystem services. A new paradigm of water governance emerges, encouraging land-use practices that explicitly take account of the multifunctional roles of water, with adequate attention to planetary freshwater boundaries and cross-scale interactions
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Rockström, J.; Falkenmark, M.; Allan, T.; Folke, C.; Gordon, L.; Jägerskog, A.; Kummu, M.; Lannerstad, M.; Meybeck, M.; Molden, D.; Postel, S.; Savenije, H.; Svedin, U.; Turton, A.; Varis, O.
The human influence on the global hydrological cycle is now the dominant force behind changes in water resources across the world and in regulating the resilience of the Earth system
. The rise in human pressures on global freshwater resources is in par with other anthropogenic changes in the Earth system (from climate to ecosystem change), which has prompted science to suggest that humanity has entered a new geological epoch, the Anthropocene. This paper focuses on the critical role of water for resilience of social-ecological systems across scales, by avoiding major regime shifts away from stable environmental conditions, and in safeguarding life support systems for human wellbeing. It highlights the dramatic increase of water crowding; near-future challenges for global water security and expansion of food production in competition with carbon sequestration and biofuel production. It addresses the human alterations of rainfall stability, due to both land use changes and climate change; the ongoing overuse of blue water, reflected in river depletion, expanding river basin closure, groundwater overexploitation, and water pollution risks. The rising water turbulence in the Anthropocene changes the water research and policy agenda, from a water resource efficiency to a water resilience focus. This includes integrated land and water stewardship to sustain wetness-dependent ecological functions at the landscape scale and a stronger emphasis on green water management for ecosystem services. A new paradigm of water governance emerges, encouraging land use practices that explicitly take account of the multifunctional roles of water, with adequate attention to planetary freshwater boundaries and cross-scale interactions. This article is protected by copyright. All rights reserved
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This paper describes an extreme flood event that occurred in the South Pare Mountains in northern Tanzania
. A high spatial and temporal resolution data set has been gathered in a previously ungauged catchment. This data was analysed using a multi-method approach, to gather information about the processes that generated the flood event. On 1 March 2006, extreme rainfall occurred in the Makanya catchment, (300 km2), where up to 100 mm were recorded in Bangalala village in only 3 h. The flood was devastating, inundating large parts of the flood plain. The spatial variability of the rainfall during the event was very large, even in areas with the same altitude. The Vudee sub-catchment (25.8 km2) was in the centre of the rainfall event, receiving about 75 mm in 3 h divided over the two upstream tributaries: the Upper-Vudee and Ndolwa. The peak flow at the weir site has been determined using the slope-area method and gradually varied flow calculations, indicating a peak discharge of 32 m3 s−1. Rise and fall of the flood was very sharp, with the peak flow occurring just one hour after the peak of the rainfall. The flow receded to 1% of the maximum flow within 24 h. Hydrograph separation using hydrochemical parameters indicates that at the floodpeak 50% of the flow was generated by direct surface runoff (also indicated by the large amount of sediments in the samples), whereas the recession originated from displaced groundwater (>90%). The subsequent base flow in the river remained at 75 l s−1 for the rest of the season, which is substantially higher than the normal base flow observed during the previous rainy seasons (15 l s−1) indicating significant groundwater recharge during this extreme event.
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