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Résultats de la recherche (216 résultats)

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  • Soil erosion by piping in irrigated fields
  • Special issue, piping erosion
  • The purposes of this paper are to point out the factors encouraging piping in irrigated soils of La Rioja, to show the effects on soil and nutrient losses in a field affected by piping during each irrigation and throughout the year, and to obtain
  • an annual rate of soil erosion by piping.
  • Variations in soil dispersivity across a gully head displaying shallow sub-surface pipes, and the role of shallow pipes in rill initiation
  • A small bifurcating gully head displaying shallow pipe development was surveyed to explore how far three-dimensional patterns of geochemistry and sediment size can be related to hydraulic gradients in the local marl bedrock (Almeria, SE Spain
  • ). It is concluded that calcium replaces sodium in the crust during leaching, leaving a calcic crust, and a sub-crust that is sodic and prone to subsequent pipe enlargement. Rill morphology in these materials also suggests that rills develop from these pipes when
  • pipe roofs collapse.
  • Perspectives on studies of badland geomorphology in Badland geomorphology and piping.
  • Introduction aux textes rassemblés par R. Bryan et A. Yair dans Geomorphology and piping Résumé des concepts et des résultats récents dans la recherche.
  • Accelerated erosion by piping in the Eastern Province, South Africa
  • Piping occurs naturally in many parts of southern Africa. In certain cases, human activity has resulted in the formation of pipes within colluvial soils of the region. Piping is developed where poorly designed backslope drainage systems have been
  • Hydrogeomorphic relations among soil pipes, flow pathways, and soil detachments within a permafrost hillslope
  • Arctique ; Canada ; Drainage ; Dégel ; Ecoulement ; Humidité du sol ; Hydrologie ; Pergélisol ; Pipe ; Périglaciaire ; Versant ; Zone froide ; Zone subarctique
  • Using data from a subarctic hillslope where detailed hydrological studies were conducted, this paper examines mechanisms of pipe formation with specific reference to cold-region and hydrogeomorphic processes. By providing a theoretical context
  • and supporting observations, linkages between pipes and other hillslope processes can be placed within the broader context of subarctic permafrost hillslope processes.
  • Hydrological connectivity of soil pipes determined by ground-penetrating radar tracer detection
  • Soil pipes are common and important features of many catchments, particularly in semi-arid and humid areas, and can contribute a large proportion of runoff to river systems. Ground Penetrating Radar (GPR) has been used for non-destructive
  • identification and mapping of soil pipes in blanket peat catchments. This paper presents results from an experiment to test the ability of GPR to establish hydrological connectivity between pipes through use of a tracer solution.
  • Spatial interaction between collapsed pipes and landslides in hilly regions with loess-derived soils
  • Ardenne ; Belgium ; Collapse structures ; Human impact ; Landslide ; Loess ; Piping ; Slope ; Slope dynamics ; Soil erosion ; Spatial analysis ; Subsurface flow ; Water erosion
  • This study aims at a better understanding of the interaction between collapsed pipe (CP) occurrence and landslide (LS) occurrence in the Flemish Ardennes (Belgium) by comparing their respective spatial patterns. At least 24,5% of the 139 sites
  • with CP were related to the occurrence of an observed LS. Poorly drained LS may create favourable conditions for pipe development. Outside LS, natural and anthropogenic (e.g. broken field drains, road drainage) causes may result in concentrated subsurface
  • flow, resulting in pipe development. No evidence was found that pipe development enhanced LS, probably because the subsurface drainage discharge generated upslope of the LS is too low. Even when pipes become blocked, it is more likely that new pipes
  • develop and new collapses occur than they trigger or reactivate LS. A conceptual model is presented summarizing all elements that influence piping erosion in the Flemish Ardennes, including the role of LS.
  • Morphological change of natural pipe outlets in blanket peat
  • Cumbria ; Drainage network ; England ; Environmental change ; Hydrogeology ; Peat bog ; Piping ; Tunnel erosion ; United Kingdom ; Watershed
  • This paper presents the first survey of natural pipe outlets in a peatland in which morphological changes in pipe outlets through time were measured. Three surveys of natural pipe outlets between 2007 and 2010 were conducted in a relatively
  • undisturbed, blanket-peat-covered catchment in northern England. The largest changes in pipe morphology occurred between July 2009 and April 2010, which spanned the coldest winter for 31 years in the UK. During this period there was a significant increase
  • in the proportion of vertically-elongated pipes and a decrease in the proportion of circular pipes. Pipe outlet morphology in blanket peat catchments is shown to be dynamic and may respond relatively quickly to changes in flow or extreme events, linked to short-term
  • Pipe flow in James Bay coastal Wetlands
  • Les pipes de drainage sont surtout alimentées par l'eau des inondations qui s'accumule très rapidement immédiatement après les périodes de pluie abondante, et l'écoulement dans les pipes devient pratiquement nul peu de temps après la cessation de
  • l'écoulement en surface. Une évaluation selon la loi de Darcy de la contribution relative de l'écoulement dû aux pipes de drainage et de l'écoulement des eaux souterraines d'un petit cours d'eau côtier montre que lorsque l'écoulement des eaux souterraines
  • contribuait pour moins de 1 % à l'écoulement d'un orage en été, les pipes fournissaient environ 10 % du drainage du cours d'eau.
  • Factors controlling the distribution of piping in Britain : a reconnaissance
  • Special issue, piping erosion
  • The distribution of piping in Britain has been studied from a survey of 74 piped basins, and a number of in-depth studies at the individual basin scale. This was undertaken to determine the factors controlling the distribution of piping at 2 scales
  • The causes of piping in a set of abandoned agricultural terraces in southeast Spain
  • This study aims to identify some of factors contributing to the piping process in abandoned terraces in 7 sites located in the Murcia Region. The local landscape has the appearance of badland geomorphology, possessing deep valleys which until
  • the 1970s were terraced and cultivated. The terraces have now been abandoned to the piping process. The research focuses on the relationship between the size and position of pipes and the physical and geochemistry properties of the local highly dispersive
  • marl lithology; and the extent to which the reworking of the materials for terrace cultivation has exacerbated piping erosion.
  • Application of ground-penetrating radar to the identification of subsurface piping in blanket peat
  • This paper presents results from an experiment to assess the use of ground-penetrating radar (GPR) to remotely sense pipes in blanket peat. The technique is shown to be successful in identifying most of the pipes tested in the pilot catchment
  • . Comparison of data on pipes identified by GPR and verified by manual measurement suggests that pipescan be located in the soil profile with a depth accuracy of 20 to 30 cm. GPR-identified pipes were found throughout the soil profile; however, those whithin 10
  • Stemflow influences on the formation of solution pipes in Bermuda eolianite
  • The objective of this study was to consider the hypothesis that the soil-filled pipes of Bermuda are the product of large volumes of acidic stemflow drainage from long-lived indigenous trees. Acidic stemflow drainage has the potential to cause
  • Vyznam nakladni potrubni dopravy. (Importance des pipe-lines pour le transport des marchandises)
  • L'A. compare les conditions de transport par pipe-lines à celles des autres modes de transport. Il souligne l'importance des transports hydraulique, pneumatique et hydro-mécanique dans le système des transports tchécoslovaques.
  • Piping causing thermokarst in permafrost, Ungava Peninsula, Quebec, Canada
  • Special issue, piping erosion
  • The aim of this short note is to describe an observation of rather unusual piping in an ice wedge from the continuous permafrost region in northernmost Quebec (mean annual temperature about -6°C). The hydrology of permafrost and its importance
  • Factors underlying piping in the Basilicata region, southern Italy
  • The aim of this study was to examine the process of pipe formation and its evolution, determine the causative factors, demonstrate the role of tectonic joints in the initiation of pipes and to develop a model to describe their development
  • Pipes in cultivated soils of La Rioja : origin and evolution
  • Pipes are a system of subsurface drainage, that can influence slope dynamics. In cultivated soils of La Rioja, their action is restricted to irrigated areas with lucerne. The factors encouraging their evolution are the number of irrigations
  • , the soil cracking, the existence of more impervious layers in the C soil horizon and hydraulic gradient. Several samples of water in the outlets of the pipes show that it is an effective system of subsurface erosion.
  • Experimental studies of pipe hydrology in Badland geomorphology and piping.
  • Piping susceptibility and the role of hydro-geomorphic controls in pipe development in alluvial sediments, Central Spain
  • Définition de valeurs-seuils des propriété des sols pour rendre compte du phénomène de piping dans les sédiments alluviaux des ranas du centre de l'Espagne. La macroporosité et le développement des fentes dans les sols sont des facteurs favorables
  • , alors qu'une importante fraction sableuse a un effet inhibiteur. Les interactions entre la géochimie de l'eau capillaire, la composition chimique et la minéralogie des argiles du sol ont aussi un effet sur le piping. La dissection par les gullies des
  • sédiments stratifiés des ranas reflète la sensibilité de différents horizons au piping. Les terrassements des versants en banquettes accélèrent le piping.
  • Soil loss rates due to piping erosion
  • Ardenne ; Belgium ; Collapse structures ; Erosion rate ; Loess ; Piping ; Soil erosion ; Temperate zone ; Water erosion
  • In this study, the significance of soil loss due to piping is demonstrated through an estimation of soil volume lost from pipes and pipe collapses in parcels under pasture on loess-derived soils in a temperate humid climate (Belgium). The results
  • gradient and drainage area largely control the location of collapsed pipes in the study area, these topographic parameters do not explain differences in eroded volumes by piping. Hence, incorporation of subsurface erosion in erosion models