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Résultats de la recherche (175 résultats)

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  • Geometric properties of river cross sections and associated hydrodynamic implications in Wuhan-Jiujiang river reach, the Yangtze River
  • Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler (ADCP) instrument, the AA. analyzed shapes of river cross sections of the middle Yangtze River basin (mainly focusing on Makou and Tianjiazhen river reach
  • ). The hydrologic data of 36 river cross sections have been successfully obtained. In this paper, the AA. try to characterize the hydrodynamic properties of river knots, associated backwater effects and their implications for flood mitigation in the middle and lower
  • Yangtze River basin are also discussed.
  • 2009
  • Healthy river and its indication, criteria and standards
  • Channel geometry ; China ; Concept ; Discharge ; Ecosystem ; Habitat ; Huang He ; Hydraulic works ; River bed ; River regime ; Stream ; Stream flow ; Sustainable development ; Water quality
  • The standards to be adopted for a healthy river should be determined according to the requirements for maintaining river's normal natural functions and the extent whether the social and natural functions could perform in a balanced way, and also
  • the standards adopted should be adjusted according to the change of the given conditions. The key factor of river health is the enough and clean flow. The AA. stressed that human activities would hurt the river health which include excessive water diversion
  • and excessive power generation from the river, improper regulation of flood and sediment, and over discharge of sewage into the river and over change in fish habitat. In China, the criteria include not only ecological criteria but also riverbed deposition degree
  • , riverbed morphology, water quality etc. Taking the Yellow River as a case, this paper also discussed the method to identify what are the standards of a healthy river as well as environmental flows.
  • 2009
  • [b3] Yellow River Conservancy Commission, Zhengzhou, Chine
  • Sustaining river ecosystems : balancing use and protection
  • Biodiversity ; Concept ; Eastern Cape ; Ecosystem ; Habitat ; Hydraulic works ; River regime ; South Africa ; Stream ; Stream flow ; Sustainable development ; Water quality ; Water resources
  • This paper suggests methods for the sustainable operation of water resource use and protection. Environmental flows (EF) for rivers are used to illustrate some of the opportunities and problems inherent in managing rivers sustainably. In particular
  • has to be integrated to provide holistic levels of understanding if sustainable management is to be achieved. Case studies from South African river research over the past 20 years are used to illustrate the policies, methods, impediments and successes
  • of sustainable river management. In particular, a recognition of complexity and change, both in ecosystems and in human thinking and behaviour, is emphasized.
  • 2009
  • Palaeochannels of the Namoi River floodplain, New South Wales, Australia : the use of multispectral Landsat imagery to highlight a Late Quaternary change in fluvial regime
  • Alluvial channel ; Australia ; Floodplain ; LANDSAT ; Meander ; New South Wales ; Palaeogeomorphology ; Quaternary ; Remote sensing ; River regime ; Stream
  • rivers : greater discharges, longer meander wavelengths and they flowed along different courses to the modern rivers. This study supports other recent investigations of the geomorphology and chronology of the Namoi River floodplain that showed
  • 2009
  • Boundary conditions of morphodynamic processes in the Mura River in Slovenia
  • Channel geometry ; Fluvial dynamics ; Grain size distribution ; Gravel ; River bed ; Sediment transport ; Slovenia ; Stream
  • In this paper, the AA. have analysed 3 key river dynamic relevant parameters, namely basic hydrologic parameters, sediment regime, and planview and cross section changes of the Mura River in Slovenia. They have obtained all available historical maps
  • and hydrological data, determined present sediment granulometry along the river and analysed changes in river morphology. The purpose of the study was to detect boundary conditions of morphodynamic processes in the Mura River in Slovenia as the first phase
  • of the River Scaling Concept (RSC)
  • 2009
  • The complex nonlinear systems with fractal as well as chaotic dynamics of annual runoff processes in the three headwaters of the Tarim River
  • This paper attempted to identify fractal and chaotic characteristics of the annual runoff processes in headwaters of the Tarim River. Methods of fractal analyses were used to explore several aspects of the temporal changes from 1957 to 2002
  • . The main findings are : 1) the annual runoff processes of the 3 headwaters of the Tarim River are complex nonlinear systems with fractal as well as chaotic dynamics; 2) the correlation dimensions of attractor derived from the time series of the annual
  • runoff for the Hotan, Yarkand and Aksu rivers imply that all 3 rivers are chaotic dynamical systems that are sensitive to initial conditions, and the dynamic modeling of their annual runoff processes requires at least 4 independent variables; 3) the time
  • series of annual runoff in each river presents a long-term correlation characteristic. The Hurst exponent for the period of 1989 to 2002 suggests that it is expected to see an increasing trend in the annual runoff of the Aksu and Yarkand rivers
  • in the years after 2002, but a decreasing tendency for the Hotan River in the same period.
  • 2009
  • Post-European settlement response gradients of river sensitivity and recovery across the upper Hunter catchment, Australia
  • This study documents the catchment-wide distribution of river sensitivity and adjustment in the upper Hunter catchment, New South Wales, in the period since European settlement. The spatial distribution and timing of lateral, vertical and wholesale
  • river adjustments are used to assess river sensitivity to change. Parish maps from the 1880s are supplemented by 5 complete sets of aerial photographs (commencing in 1938) to analyse differing forms of river adjustment along 13 river courses. Adjustments
  • have been largely non-uniform and localized, reflecting the predominance of bedrock-controlled rivers which have limited capacity to adjust and are resilient to change. Phases of reach-scale geomorphic adjustment to human disturbance are characterized
  • 2009
  • Palaeohydrologic conditions and geomorphic processes during the Postglacial in the Palatine Upper Rhine river floodplain
  • Stratigraphic, palynological, sedimentological, geophysical and mollusc analyses of 3 peat cores from palaeomeanders in the floodplain of the Southern Palatine Upper Rhine river valley were used to reconstruct interrelations between palaeohydrologic
  • in the Younger Holocene. Sediment layers within the upper peat layers of the palaeomeanders show a vast increase of flood activity of the Upper Rhine river since the High- and Late Middle Ages. From that time onwards huge areas of the Rhine river floodplain were
  • 2009
  • Strategic coupling of regional development in global production networks : redistribution of Taiwanese personal computer investment from the Pearl River Delta to the Yangtze River Delta, China
  • l'investissement taiwanais en ordinateurs personnels du delta de la Pearl River au delta du Yangtze en Chine.
  • 2009
  • Flood ; Flood control ; Hungary ; Hydraulic works ; Hydrology ; River regime ; Stream ; Watershed
  • One of the greatest river regulation schemes of Europe was implemented in Hungary during the second half of 19th century. River control, flood protection and other human interventions on the watershed bought unambiguous and measurable changes
  • in the natural regime of Hungarian rivers. The study focuses on the flood stages of Hungarian rivers and presents the special hydrological situation of the Lower Tisza district. - (AM)
  • 2009
  • Retrieval of suspended sediment concentrations in large turbid rivers using Landsat ETM+ : an example from the Yangtze River, China
  • Suspended sediment concentration (SSC) is a critical parameter in the study of river sediment transport and water quality variation. This paper is focused on presenting a methodology that may be useful in estimating SSC which is of key importance
  • in process geomorphology and hydrology. The dataset used in this paper includes measured SSC and multi-temporal Landsat ETM+ images covering most part of the Yangtze River. A newly developed regression relation between SSC and water reflectance of Band 4
  • appears to be able to provide a relatively accurate SSC estimate directly from Landsat ETM+ images for the Yangtze River from the upper, the middle to the lower reaches.
  • 2009
  • Morphological change at the Snowy River ocean entrance, Victoria, Australia (1851-2008)
  • Analysis of data, including historical documentation, survey and navigation charts, and aerial imagery, representing a time series of 1851-2008 for the Snowy River ocean entrance area (located in East Gippsland) shows that much morphological change
  • has occurred, including entrance channel migration along 8000 m of Holocene sandy barrier formation. Increasingly frequent episodes of Snowy River entrance channel closure to Bass Strait is apparent from reference to the 1981-2008 record. The GIS
  • -electricity Scheme (SMHS) from 1951, which currently appropriates the vast majority of annual discharge from the high rainfall and snowfall areas of the upper Snowy River catchment. Whilst ebb-flow augmentation via stream flow discharge is essential
  • to the maintenance of the Snowy River entrance, the Snowy River entrance is likely to remain ephemeral in the future as a direct consequence of inter-regional water transfer and climate change.
  • 2009
  • Avulsion regimes in southeast Texas rivers
  • Avulsion ; Braided channel ; Channel geometry ; Digital elevation model ; Floodplain ; Fluvial hydrology ; Human impact ; Inheritated geomorphological features ; Quaternary ; River regime ; Stream ; Texas ; United States of America
  • In the southeast Texas coastal plain, avulsions were studied on the lower Brazos, Navasota, Trinity, Neches and Sabine rivers using a combination of aerial imagery, digital elevation models and field surveys. Avulsions have important influences
  • on the surface morphology and contemporary processes in all 5 rivers. Features associated with avulsions are active and distinct throughout the study area, and all the rivers have experienced geologically (if not historically) recent avulsions. However, no two
  • of the study rivers have the same contemporary avulsion regime. First-orde differences in avulsion style are controlled by the stage of valley filling, and within the 3 ivers characterized by an unfilled incised valley, antecedent morphology associated
  • 2009
  • Karst processes and phenomena in the perennially frozen carbonate rocks of the Middle Lena River Basin
  • Various karst processes and karst phenomena at scales from the macro to the micro occur in the cryolithozone of the middle Lena River basin. Karst processes have a warming impact on the enclosing perennially cryotic rocks and favour the formation
  • 2009
  • River response to continuing movements along the active faults in the Siang Valley, North-Eastern Himalaya, India
  • This paper describes the relevant geomorphic features with special reference to river responses associated with active faults in Siang Valley of Arunachal Pradesh. The optically Stimulated Luminescence (OSL) dating is applied on the alluvial cover
  • of the terraces provided an opportunity to access the bedrock incision rate of the river and to draw chronological framework of the neotectonic activity. A geological map is presented after extensive regional fieldwork during the last one decade. Survey of India
  • 2009
  • The spatial and temporal patterns of aggradation in a temperate, upland, gravel-bed river
  • Bank erosion ; Climatic change ; England ; Flood ; Fluvial dynamics ; Gravel ; Land use ; Natural hazards ; River bed ; Sediment transport ; Stream ; Temperate zone ; United Kingdom ; Yorkshire
  • . In doing so, this work assesses the importance of coarse sediment transfer in river management, particularly as the climate and land-use change.
  • 2009
  • Did the Nile River flow to the Gulf of Sirt during the late Miocene ?
  • that, before the Late Messinian drawdown of the Mediterranean Sea, the River Nile flowed into the Libyan palaeo-Sirt. The study is still in progress; in this paper data are presented from three areas, showing evidence of palaeo-drainage of Tortonian-Late
  • Messinian age, that could be considered sufficient to delineate the course of the Nile River up to the Gulf of Sirt. - (NF)
  • 2009
  • Quaternary evolution of the Pecora River (Southern Tuscany, Italy : paleohydrography and sediments provenance
  • This new reinterpretation of the Quaternary evolution of the Pecora River area has several implications, in particular on the nature of the arsenic anomaly known in this area and mainly confined to the fluvial terrigenous deposits. Specifically
  • , the erosion and dispersal of As-bearing mineralization emplaced between the late Pliocene and the Quaternary in fractures and faults affecting the bedrock of the Arsenti Mount area, was possibly driven by the sedimentary development of the Pecora River
  • 2009
  • Dust source of the Holocene loess-soil and pedogenic environmental changes in the upper Huaihe River
  • susceptibility, pH value distribution, loss on ignition and particle-size distribution. It was concluded that the dust source of loess in the upper reaches of the Huaihe River Basin was different from that in the Loess Plateau, and the Holocene pedogenic
  • environmental changes in the upper reaches of the Huaihe River Basin were revealed.
  • 2009
  • Strategy or disaster. Flood prevention related issues and actions in the Tisza River basin
  • Changes in land use of the lowland landscape along the Tisza River have largely been shaped by processes that took place after flood control and regulation measures of that river. As a result fluvial accumulation has either been eliminated
  • 2009