inscription
Portail d'information géographique

Résultats de la recherche (203 résultats)

Affinez votre recherche

Par Collection Par Auteur Par Date Par Sujet Par Titre
  • Sediment transport in the drainage area of Ribe Å
  • Carrying capacity ; Catchment area;Watershed ; Denmark ; Drainage network ; Erosion balance;Erosion budget ; Fluvial processes ; Sediment transport ; Soil erosion ; Streams
  • The objectives of this paper are to quantify the sediment transport leading to the wetland area, to describe the areal variation of transport rates and sediment sources and to establish a sediment balance for the system. Only general remarks
  • on technical solutions of the sedimentation problem are included.
  • 1991
  • Fluvial sediment budgets in the North Carolina Piedmont
  • Catchment area;Watershed ; Fluvial processes ; North Carolina ; Pollution ; Sediment budget ; Soil erosion ; United States
  • The purpose of this study is to estimate and examine rudimentary sediments budgets for four river basins in the Piedmont physiographic province of North Carolina to determine the relative magnitude and importance of sediment storage.
  • 1991
  • Absence of caesium-137 from recent sediments in eastern Australia. Indications of catchment processes?
  • Here the AA. report on a reconnaissance survey of the 137Cs content of recent alluvial sediments in the Hunter valley, N.S.W., Australia. They attribute the absence of 137Cs from recent sediments, in part, to the nature and magnitude
  • of the catchment processes associated with the entrainment and subsequent deposition of the sediments.
  • 1991
  • Upland and coastal sediment sources in a Chesapeake Bay estuary
  • Action anthropique ; Baie ; Chesapeake ; Cours d'eau ; Erosion littorale ; Estuaire ; Etats-Unis ; Fluviatile ; Gestion de l'environnement ; Gestion des ressources ; Littoral ; Maryland ; Palynologie ; Sédimentation ; Sédimentologie
  • Bay ; Chesapeake ; Coastal environment ; Coastal erosion ; Environment management ; Estuary ; Fluvial processes ; Human impact ; Maryland ; Palynology ; Resource management ; Sedimentation ; Sedimentology ; Stream ; United States
  • New data from the South River, Maryland and reexamination of existing literature suggest that coastal erosion may be the dominant process driving sediment inputs along the lenght of many tributary estuaries of the Chesapeake. This paper addresses
  • those issues by developing a sediment budget for the upper South River and examining resource management implications of that budget.
  • 1991
  • Quartz concentration as an index of sediment mixing : hydraulic mine-tailings in the Sierra Nevada, California
  • Hydraulic gold mining delivered large volumes of sediment to northern California stream channels from 1853 to 1884. Distinctive quartz composition of this sediment allow development of a sediment mixing index for determination of tailings
  • concentrations in contemporaneous and reworked deposits. This index reveals patterns of sediment mixing in the Bear River, California over the last 100 years.
  • 1991
  • Technique sismique pour la mesure de l'épaisseur des sédiments de mer profonde
  • Géomorphologie sous-marine ; Géophysique ; Méthodologie ; Océanologie ; Sismique réflexion ; Sédiment marin
  • Geophysics ; Marine sediment ; Methodology ; Oceanology ; Seismic reflection ; Submarine geology
  • Description des objectifs et de l'instrumentation utilisée pour la mesure de la puissance des sédiments en eau profonde par la méthode des mesures de sismiques réflexions.―(MC)
  • 1991
  • Bassin-versant ; Charge solide ; Ecoulement ; Fluviatile ; Hydrologie ; Inondation ; Montagne ; Ruissellement ; Rwanda ; Régime hydrologique ; Sédimentation ; Zone intertropicale
  • Catchment area;Watershed ; Flood ; Flow ; Fluvial processes ; Hydrological regime ; Hydrology ; Mountain ; Rill wash;Runoff ; Rwanda ; Sediment load ; Sedimentation ; Tropical zone
  • Land use, geology and topography account for the differences in sedimentation and flooding in four watersheds in densely settled Ruhengeri prefecture.―(DWG)
  • 1991
  • Aeolian decoupling of beach sediments
  • California ; Dune ; Erosion littorale ; Etats-Unis ; Granulométrie ; Littoral ; Plage ; Reptation ; Sable ; Sédiment marin ; Transport éolien
  • Beach ; California ; Coastal environment ; Coastal erosion ; Creep ; Dune ; Eolian transport ; Grain size distribution;Granulometry ; Marine sediment ; Sand ; United States
  • 1991
  • The impact of rainfall on sediment transport by sheetflow
  • Experimentation ; Flow ; Precipitation ; Rainfall simulation ; Sediment transport ; Slope ; Slope gradient ; Soil erosion
  • Discussion of the results of experiments using simulated rainfall. It is shown that, because film thickness increases, the direct impact of rainfall on sediment transport decreases with slope length.
  • 1991
  • Formation of stationary alternate bars in a steep channel with mixed-size sediment : a flume experiment
  • Alternate bars were formed by sediment transport in a flume with Froude-modelled flow and relative roughness characteristic of gravel-boulder channels with steep slopes. This paper describes the experiment and present arguments that steep channel
  • gradients and widely graded sediment enhance the stability of alternate bars.
  • 1991
  • Sediment yield and delivery in the blanket peat moorlands of the southern Pennines
  • This research attempts to add to the existing knowledge of peat-covered catchments by adopting investigations at various temporal and spatial scales to illuminate patterns of sediment erosion and sediment yield in peat-covered catchments.
  • 1991
  • Empirical relations for the sediment transport capacity of interrill flow
  • Belgium ; Grain size distribution;Granulometry ; Precipitation ; Rill wash;Runoff ; Sediment transport ; Slopes ; Soil erosion
  • Experiments were carried out in order to measure the sediment transport capacity of interrill flow with and without rainfall and to relate the transport capacity to selected hydraulic parameters, such as effective stream power and shear velocity
  • . Different sediments were used in order to study the effect of grain size. The proposed relationship show considerable variations with grain size and there is only a minor effect of rainfall on the transport capacity which also seems to be grain size
  • 1991
  • Glacitectonic deformation in sediment and bedrock, Hat Creek, British Columbia
  • British Columbia ; Canada ; Cold areas ; Fault ; Glacial features ; Model ; Sediment filling ; Tectonics
  • Etude des structures de déformation attribuées au chevauchement glaciaire qui se manifestent dans la roche en place et les sédiments de la vallée intramontagnarde du Hat Creek, en Colombie-Britannique. Présentation d'un modèle de la formation
  • glacitectonique d'éjections hydrauliques durant la compression des sédiments sous-terrains non gelés partiellement saturés.
  • 1991
  • Coarse sediment transport in an experimental high mountain catchment of Central Pyrenees, Spain
  • Carrying capacity ; Catchment area;Watershed ; Experimentation ; Grain size distribution;Granulometry ; Precipitation ; Pyrénées ; Seasonal variation ; Sediment transport ; Snow ; Soil erosion ; Spain
  • A small catchment has been monitored in the high Gallego river basin (Central Spanish Pyrenees). The results show the great importance of autumn and occasional summer rainstorms for the sediment output. Sediment transport is negligible in winter
  • and adds little to the total volume during spring. Moreover, during the snowmelt, sediments are finer than those produced by rainstorms due to the hydrologic conditions and the different sediment sources.
  • 1991
  • The deposition of eolian sediments in lacustrine and fluvial environments of Central Sinai (Egypt)
  • Carbonate ; Egypte ; Eolien ; Granulométrie ; Loess ; Minéralogie ; Paléo-environnement ; Sinaï ; Sédiment lacustre ; Terrasse fluviatile
  • Carbonate ; Egypt ; Eolian features ; Fluvial terrace ; Grain size distribution;Granulometry ; Lacustrine sediment ; Loess ; Mineralogy ; Palaeo-environment ; Sinai
  • In the Central Sinai the Precambrian rocks of the crystalline basement are partly covered with fine-grained, marly sediments. The sediments indicate a periodic change between more fluvial, coarser horizons and more finegrained, eolian horizons which
  • have been accumulated under stillwater conditions. The present paper shall contribute to solve the differing opinions about the petrogenesis of the silty sediments including their provenance.
  • 1991
  • Holocene sediment production in Lillooet River basin, British Columbia : a sediment budget approach
  • British Columbia ; Canada ; Catchment area;Watershed ; Cold areas ; Glacial features ; Holocene ; Human impact ; Landslides ; Paleo-environment ; Sediment budget ; Volcanism
  • Etude, par le bilan sédimentaire, de la sédimentation au cours de l'Holocène dans le bassin de la Lillooet River, Colombie-Britannique. Mise en évidence des principaux facteurs qui influencent la sédimentation : les périodes de volcanisme, les
  • 1991
  • Glacial-marine sedimentation, canadian polar margin, north of Axel Heiberg Island
  • Arctique ; Axel-Heiberg Island ; Canada ; Foraminifère ; Holocène ; Palynologie ; Paléogéographie ; Quaternaire ; Sédimentation glacio-marine ; Sédimentologie
  • L'étude des carottes de sédiments recueillies à des profondeurs de 140 à 300 m sur la plate-forme de l'île Axel-Heiberg (82oN) renseigne sur la mise en place des sédiments sous une glace de mer pérenne. Mise en évidence de cinq faciès sédimentaires
  • et interprétation du processus de sédimentation à partir de la sédimentologie, de la palynologie et des foraminifères.
  • 1991
  • Bibliography ; Carrying capacity ; Fluvial processes ; Gravel ; Hydrodynamics ; River bed ; Sediment transport ; Sedimentology ; Turbulence
  • This progress report reviews the research into the processes of : 1) coarse surface layers; 2) armour versus pavement; 3) bed surface structure and sediment transport; 4) imbrication; 5) small- and medium-scale gravel bedforms; 6) gravel bedforms
  • and sediment transport.
  • 1991
  • Water and sediment yields into the Sutlej River from the High Himalaya
  • In this river system whose water is derived mainly from snowmelt, an analysis of nine years of hydrologic data shows little variation in runoff, but great variation in sediment yield, mostly as a result of soil erosion caused by human agency. - (DWG)
  • 1991
  • Ferrimagnetic sulfide formation in recent sediments of Loch Ba, Scotland and implications for magnetostratigraphic interpretation
  • Authigenèse ; Géochimie ; Géographie de l'Europe ; Magnétostratigraphie ; Minéralogie ; Paléo-environnement ; Quaternaire ; Royaume-Uni ; Scotland ; Sédiment lacustre
  • 1991