inscription
PORTAIL D'INFORMATION GÉOGRAPHIQUE

Résultats de la recherche (183 résultats)

Affinez votre recherche

Par Collection Par Auteur Par Date Par Sujet Par Titre
  • Modelling the impact of anthropogenic modifications to river channels on the course of extreme floods
  • Czech Republic ; Flood ; Human impact ; Impact ; Modelling ; River bed
  • This paper presents the results of analysis of the impact of anthropogenic modifications to river channels on the course of floods by means of hydraulic modeling. The study is focused on the quantitative analysis of changes of the flow dynamics
  • in the river bed and in the inundation zone due to river network modifications. The one-dimensional hydraulic model HEC-RAS coupled with GIS is used to simulate the effect of the river channel changes on the course of extreme flood. - (EN)
  • 2008
  • Spatial and temporal variation of runoff of Red River Basin in Yunnan
  • This paper studies the variation of runoff of Red River Basin and discusses the influence of corridor-barrier functions of valleys and mountains on variation of runoff by using GIS and statistic methods based on the monthly precipitation
  • , temperature and evaporation data from 1960 to 2000 at 32 meteorological stations in Red River Basin, and the annual runoff data of Yuanjiang River, Lixian River and Panlong River from 1956 to 2000. These 3 river basins are contrasted. Results and discussion.
  • 2008
  • [b1] Asian International Rivers Center, Yunnan University, Kunming, Chine
  • Discrimination of channel patterns for gravel- and sand-bed rivers
  • Braided channel ; Discriminant analysis ; Gravel ; Meander ; River bed ; Runoff ; Sand ; Shear stress ; Stream ; Stream flow
  • Based on data from around 200 alluvial rivers in several countries, a systematic comparison of flow shear stress and stream power has been made between sand- and gravel-bed rivers. The formation of channel pattern can be regarded as the outcome
  • of sediment transport and channel bank constraints in an alluvial river. To overcome the difficulty of quantifying channel bank constraints, channel width/depth ratio and a dimensionless channel width index are used to reflect it indirectly.
  • 2008
  • Measuring river velocities using GPS River Flow Tracers (GRiFTers)
  • This paper introduces the use of GPS drifters (termed GRiFTers) to measure surface flow velocities in a 400 m reach of the River Swale, UK. The technique shows great promise to provide new insights into flow patterns over long reaches of rivers
  • 2008
  • Downstream variation in bed sediment size along the East Carpathian rivers : evidence of the role of sediment sources
  • Carpathian Mountains ; Drainage network ; Grain size distribution ; River bed ; Romania ; Sediment budget ; Sediment load ; Sedimentology ; Stream ; Suspended load
  • This paper intends to approach the phenomena of river-bed material variability inside a network of rivers from the drainage basin of Siret as a link between sediment sources and their sediment delivery. The AA. will focus on the spatial variability
  • of the distribution types of river-bed material and will try to moot the origin of bimodality of river-bed deposits. As opposed to its tributaries, the source of the first mode, of gravel, is allochtonous to the Siret river, generated by the massive input of coarse
  • 2008
  • Analysis of bedload transport characteristics of Idaho streams and rivers
  • Data collected for 33 sites on 31 mountain streams and rivers in Central Idaho have enabled the analysis of sediment transport characteristics in streams and rivers with different geological, topographic, morphological, hydrological, hydraulic
  • are used to identify different influences on bedload transport rates in analyzed gravel-bed rivers.
  • 2008
  • Assessing the ability of airborne LiDAR to map river bathymetry
  • Airborne bathymetric LiDAR was collected for 220 river kilometers in the Yakima and Trinity River Basins in the USA. Concomitant with the aerial data collection, ground surveys of the river bed were performed in both basins. The AA. assess
  • 2008
  • Wood as a driver of past landscape change along river corridors
  • The role of wood as a driver of landform development appears to have been overlooked in the interpretation of paleo-landscape change along river corridors. Deforested river corridors and wood-free rivers characterize modern, managed landscapes
  • , but along natural river corridors both driftwood dynamics and tree reproductive strategies can have a dramatic impact on the style and rate of channel and floodplain development. Therefore, the AA. believe that interpretations of the post-glacial history
  • of river valleys across the northern temperate climatic zone could be usefully reassessed, incorporating the roles of riparian trees.
  • 2008
  • Impacts of dams on the sediment flux of the Pearl River, southern China
  • Based on datasets begun in the 1950s of water and sediment flux at the main gauging stations and measured deposition rates in some reservoirs, this paper examines the impact of dam construction on the sediment flux of the Pearl River. The results
  • and conclusions show that the sediment flux of the Pearl River has shown a drastically decreasing trend since the mid-1980s, which is attributed mainly to deposition in the reservoirs. A further decrease in sediment flux into the sea is expected to occur
  • in the Pearl River in future decades because of the construction of new dams with big impacts on the environments of the river channel, the estuary and the coastal areas.
  • 2008
  • A suspended sediment budget of the Yichang-Wuhan reach of the Yangtze River, China
  • Carrying capacity ; China ; Human impact ; Multiple regression ; River bed ; Sediment budget ; Stream ; Suspended load
  • The amount of the sediment deposition in the Yichan-Wuhan reach of the middle Yangtze River has been determined using the concept of sediment budget at the channel-reach scale. The fill-scour processes of the middle Yangtze River were studied during
  • the period 1956-1997 in response to the variation in sediment load and flow inputs. Multiple regression equations have been established to assess the contributions of influencing factors to the variation in sediment deposition amount in the studied river
  • 2008
  • Persistence of the surface texture of a gravel-bed river during a large flood
  • Channel geometry ; Colorado ; Flood ; Grain size distribution ; Gravel ; Meander ; Meltwater ; Pic discharge ; River bed ; Stream ; United States of America
  • The goal of this paper is to clarify conditions under which the surface layer of a gravel-bed river may persist during large floods. Detailed field measurements of channel topography and bed surface grain size were made in a gravel-bed reach
  • of the Colorado River prior to a flood in 2003. Runoff produced during the 2003 snowmelt was far above average, resulting in a sustained period of high flow with a peak discharge; all available grain sizes within the study reach were mobilized in this period
  • of time. During the 2003 peak flow, the river avulsed immediately upstream of the sudy reach. The abandonment was rapid, leaving the bed texture essentially frozen in place.
  • 2008
  • Evolution of Quaternary river terraces related to the uplift of the central part of the Bohemian Massif
  • Fluvial sediments in the Vltava, Berounka, Sázava and Labe valleys are preserved as extensive river terrace sequences. These accumulation terraces originated from an interaction of climate-morphogenetic and neotectonic processes in the late Cenozoic
  • 2008
  • Configuration of channel bars in Černá Opava River as a consequence of flooding in September 2007
  • Czech Republic ; Flood ; Floodplain ; River bed
  • The article deals with changes of setting of channel bars which originate from the overbank flooding events. Channel bars carry information about a flow behavior during and out of flooding. They characterize processes inside the river channel
  • 2008
  • Erosion and accumulation flood landforms in Sázava River in spring 2006
  • Czech Republic ; Erosion ; Flood ; Floodplain ; Fluvial deposit ; River bed
  • This article deals with channel bars, flood accumulations of floodplain and bank scours as the most important geomorphologic effects of the spring flood in Sázava River in 2006. The article deals particularly with its spatial distribution
  • 2008
  • Flood frequency and seasonality in the Sázava river catchment based on historical cases
  • The paper gives an overall report on historical floods in the Sázava River Basin, focused on the pre-instrumental period in particular. The paper presents the first more detailed chronology of flood events on the Sázava River within the time limits
  • 2008
  • Decadal changes in distribution and frequency of wood in a free meandering river, the Ain River, France
  • This study examined the temporal dynamics and longitudinal distribution of wood over a multi-decadal timescale at the river reach scale (36 km) and a meander bend scale (300-600 m) in the Ain River, a large gravel-bed river flowing through
  • a forested corridor, and adjusting to regulation and floodplain land-use change. At the reach scale they estimate wood production to the river from the riparian forest by bank erosion over a six-decade time period, and describe the distribution (longitudinal
  • -bed rivers.
  • 2008
  • Impact of groundwater flow on meandering; example from the Geul River, The Netherlands
  • The Geul River, located in the south-eastern part of The Netherlands, is a meandering river with a planform shape characterized by large loops consisting of multiple bends. The AA. evaluate the effects of groundwater flow on the shapes of meanders
  • 2008
  • Optical remote mapping of rivers at sub-meter resolutions and watershed extents
  • techniques play a major role. This paper therefore highlights and evaluates recent advances and capabilities specific to optical remote sensing of rivers. Example for the Nueces River, Texas.
  • 2008
  • Seasonal and spatial distribution of heavy metals in the Selenga River Delta
  • In order to estimate the present-day polution levels in the ecosystem of the Selenga River Delta and to monitor the changes caused by the discharge of household refuse and industrial wastes, as well as the functioning of the agricultural and stock
  • farming, a study of the water and bottom sediments in the main branches of the Selenga River Delta was carried out. This study has determined the concentrations of heavy metals in river water and bottom sediments in its delta.
  • 2008
  • Effect of altered flow regime on bankfull area of the Lower Yellow River, China
  • Bank erosion ; China ; Discharge ; Henan ; Human impact ; River regime ; Stream ; Stream flow ; Suspended load
  • This paper presents a study on the effects of altered discharge and suspended sediment load on the bankfull area at Gaocun, a representative hydrometric station in the Lower Yellow River. The analysis demonstrates the cumulative effect of previous
  • 2008
  • [b2] Yellow River Inst. of Hydraulic Research, Zengzhou, Chine