391 resultados para Yangtze floodplain


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The carbon, oxygen, and strontium isotope composition of enamel from teeth of large Miocene herbivorous mammals from Sandelzhausen (MN5, late Early/early Middle Miocene) in the North Alpine foreland basin, were analyzed to infer diet and habitat. The mean enamel delta(13)C value of -11.4 +/- 1.0% (n = 53) for the nine taxa analyzed (including proboscideans, cervids, suids, chalicotheres, equids, rhinocerotids) indicates a pure C(3) plant diet for all mammals. (87)Sr/(86)Sr ratios of similar to 0.710 higher than those from teeth of the western Molasse Basin (0.708-0.709) seem to indicate preferential feeding of the mammals in the northeastern Molasse Basin. The sympatric herbivores have different mean delta(13)C and delta(18)O values which support diet partitioning and/or use of different habitats within a C(3) plant ecosystem. Especially the three sympatric rhinoceroses Plesiaceratherium fahlbuschi, Lartetotherium sansaniense, and Prosantorhinus germanicus show clear partitioning of plants and/or habitats. The palaeomerycid Germanomeryx fahlbuschi was a canopy folivore in moderately closed environments whereas Metaschizotherium bavaricum (Chalicotheriidae) and P. germanicus (Rhinocerotidae) were browsers in more closed forest environments. The horse Anchitherium aurelianense was probably a more generalized feeder than assumed from its dental morphology. The forest hog Hyotherium soemmeringi has the highest delta(13)C and lowest delta(18)O value of all analyzed taxa, possibly related to a frugivorous diet. Most taxa were water-dependent browsers that record meteoric water delta(18)O values of about -5.6 +/- 0.7% Vienna Standard Mean Ocean Water (VSMOW). Using a modern-day mean annual air temperature (MAT)-delta(18)OH(2)O relation a MAT of 19.3 +/- 1.5 degrees C can be reconstructed for Sandelzhausen. A Gomphotherium subtapiroideum tusk serially sampled for delta(18)O values does not record a clear pattern of seasonality. Thus most taxa were C(3) browsers in a forested and humid floodplain environment in the Molasse Basin, which experienced a warm-temperate to subtropical climate and possibly low seasonality.

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This paper reviews the role of alluvial soils in vegetated gravelly river braid plains. When considering decadal time scales of river evolution, we argue that it becomes vital to consider soil development as an emergent property of the developing ecosystem. Soil processes have been relatively overlooked in accounts of the interactions between braided river processes and vegetation, although soils have been observed on vegetated fluvial landforms. We hypothesise that soil development plays a major role in the transition (speed and pathway) from a fresh sediment deposit to a vegetated soil-covered landform. Disturbance (erosion and/or deposition), vertical sediment structure (process history), vegetation succession, biological activity and water table fluctuation are seen as the main controls on early alluvial soil evolution. Erosion and deposition processes may not only act as soil disturbing agents, but also as suppliers of ecosystem resources, because of their role in delivering and changing access (e.g. through avulsion) to fluxes of water, fine sediments and organic matter. In turn, the associated initial ecosystem may influence further fluvial landform development, such as through the trapping of fine-grained sediments (e.g. sand) by the engineering action of vegetation and the deposit stabilisation by the developing above and belowground biomass. This may create a strong feedback between geomorphological processes, vegetation succession and soil evolution which we summarise in a conceptual model. We illustrate this model by an example from the Allondon River (CH) and identify the research questions that follow.

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River bifurcations are critical but poorly understood elements of many geomorphological systems. They are integral elements of alluvial fans, braided rivers, fluvial lowland plains, and deltas and control the partitioning of water and sediment through these systems. Bifurcations are commonly unstable but their lifespan varies greatly. In braided rivers bars and channels migrate, split and merge at annual or shorter timescales, thereby creating and abandoning bifurcations. This behaviour has been studied mainly by geomorphologists and fluid dynamicists. Bifurcations also exist during avulsion, the process of a river changing course on a floodplain or in a delta, which may take 102103 years and has been studied mainly by sedimentologists. This review synthesizes our current understanding of bifurcations and brings together insights from different research communities and different environmental settings. We consider the causes and initiation of bifurcations and avulsion, the physical mechanisms controlling bifurcation and avulsion evolution, mathematical and numerical modelling of these processes, and the possibility of stable bifurcations. We end the review with some open questions. Copyright (c) 2012 John Wiley & Sons, Ltd.

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The RIO’S 90-page July Quarterly Report details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart growth; mitigation planning; floodplain and watershed management; floodplain mapping; quality of life; and emergency management.The report also includes an updated selection of charts showing the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.

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The RIO’S October Quarterly Report details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart growth; mitigation planning; floodplain and watershed management; floodplain mapping; quality of life; and emergency management.The report also includes an updated selection of charts showing the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.

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The RIO’S January 2010 Quarterly Report details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart growth; mitigation planning; floodplain and watershed management; floodplain mapping; quality of life; and emergency management.The report also includes an updated selection of charts showing the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.

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The RIO’S April 2010 Quarterly Report details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart growth; mitigation planning; floodplain and watershed management; floodplain mapping; quality of life; and emergency management.The report also includes an updated selection of charts showing the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.

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The RIO’S July 2010 Quarterly Report details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart growth; mitigation planning; floodplain and watershed management; floodplain mapping; quality of life; and emergency management.The report also includes an updated selection of charts showing the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.

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The RIO’S October 2010 Quarterly Report details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart growth; mitigation planning; floodplain and watershed management; floodplain mapping; quality of life; and emergency management.The report also includes an updated selection of charts showing the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.

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The Flood Plain Management and Hazard Mitigation Task Force emphasizes the long-term benefits of mitigation and management to the entire state in preventing or reducing damages from floods and other hazards faced in Iowa. Investments in efforts to manage watershed areas and to mitigate any damages from floods or other disaster events benefit individuals, families, communities, agriculture, business and industry, and certainly public entities and infrastructure. The Task Force encourages the Rebuild Iowa Advisory Commission to balance the immediate needs for rebuilding to include the beginning of the investments required to effectively mitigate future damage and maintain effective policy in Iowa’s watersheds. The significance of the damage seen in Iowa from the tornadoes, storms, and floods of 2008 include the loss of eighteen Iowans in disaster-related events. This alone should inspire investment in mitigation efforts for all hazards. Much of the damage resulting from the disasters can be tied to floodplain management and hazard mitigation, pointing the way toward enhanced efforts and new initiatives to safeguard lives, property, and communities’ economic health. Even so, it must be recognized that the weather events throughout last winter and spring added impetus to the rains and storms that ultimately resulted in record flooding. Some perspective must be maintained as planning progresses and significant investments in mitigation are considered to meet a specific level of safety and protection from future threats. The Task Force identified a number of issues, and four were agreed-upon as those with the highest priority to be addressed by the Task Force through a set of recommendations.

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The Flood Plain Management and Hazard Mitigation Task Force emphasizes the long-term benefits of mitigation and management to the entire state in preventing or reducing damages from floods and other hazards faced in Iowa. Investments in efforts to manage watershed areas and to mitigate any damages from floods or other disaster events benefit individuals, families, communities, agriculture, business and industry, and certainly public entities and infrastructure. The Task Force encourages the Rebuild Iowa Advisory Commission to balance the immediate needs for rebuilding to include the beginning of the investments required to effectively mitigate future damage and maintain effective policy in Iowa’s watersheds. The significance of the damage seen in Iowa from the tornadoes, storms, and floods of 2008 include the loss of eighteen Iowans in disaster-related events. This alone should inspire investment in mitigation efforts for all hazards. Much of the damage resulting from the disasters can be tied to floodplain management and hazard mitigation, pointing the way toward enhanced efforts and new initiatives to safeguard lives, property, and communities’ economic health. Even so, it must be recognized that the weather events throughout last winter and spring added impetus to the rains and storms that ultimately resulted in record flooding. Some perspective must be maintained as planning progresses and significant investments in mitigation are considered to meet a specific level of safety and protection from future threats. The Task Force identified a number of issues, and four were agreed-upon as those with the highest priority to be addressed by the Task Force through a set of recommendations. Supplemental Information to the August 2008

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The RIO’S January 2011 Quarterly Report details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart planning; mitigation planning; floodplain and watershed management; floodplain mapping and quality of life. The report also includes an update of the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.

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The RIO’S April 2011 Quarterly Report is the Office's final report and details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart planning; mitigation planning; floodplain and watershed management; floodplain mapping and quality of life. The report also includes an update of the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.

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The Pantanal region can be characterized as a quaternary floodplain with predominant sedimentation in the form of alluvial fans. In the geomorphologic and sedimentary evolution, the avulsion process is inherent to this depositional system and its dynamics, together with surface water floods, influence soil sedimentation on this plain. The knowledge and differentiation of these two events can contribute to a better understanding of the variability of soil properties and distribution under the influence of these sedimentation processes. Therefore, this study investigated the genesis of soils in the Northern Pantanal with textural contrasts in deeper horizons and their relationship with the depositional system dynamics. We analyzed four soil profiles in the region of Barão de Melgaço, Mato Grosso State, Brazil (RPPN SESC Pantanal). Two profiles were sampled near the Rio Cuiabá (AP1 and AP4) and two near the Rio São Lourenço (AP10 and AP11). In AP11, the horizons contrast in particle size between the profile basis and the surface. In AP1, AP4 and AP10, the horizons overlaying the sand layer have similar particle size properties, mainly in terms of sand distribution. In the first case, floods (surface water) seem to have originated the horizons and layers with contrasting texture. In the second case, avulsion is the most pronounced process. Therefore, the two modes can form soils with contrasting texture that are discriminable by soil morphology, based on the distinct features associated to the specific sedimentation processes.

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The RIO’S quarterly Report details the economic recovery strategy in housing; business; workforce development; infrastructure investments; individual services and guidance; local economic recovery; smart growth; mitigation planning; floodplain and watershed management; floodplain mapping; quality of life; and emergency management.The report also includes an updated selection of charts showing the flow of federal and state disaster recovery funding to the state, counties, cities and individuals affected by the 2008 disasters.