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Portail d'information géographique

Résultats de la recherche (15 résultats)

Gully-head morphology and implications for gully development on abandoned fields in a semi-arid environment, Sierra de Gata, southeast Spain

Gully-head morphology and implications for gully development on abandoned fields in a semi-arid environment, Sierra de Gata, southeast Spain

Field experiments on the transport of rock fragments by animal trampling on scree slopes

Field experiments on the transport of rock fragments by animal trampling on scree slopes

Topographical thresholds for ephemeral gully initiation in intensively cultivated areas of the Mediterranean

Ephemeral gullying is an important erosion process in Mediterranean areas. The objective of this study was to investigate to what extent one could use field measurements of S (local slope) and A (drainage-basin area) to predict the location

Spatial distribution of gully head activity and sediment supply along an ephemeral channel in a Mediterranean environment

in the field by pre-defined criteria. The results showed that land use and lithology have a significant impact on bank gully head activity. It was further investigated whether the gully heads were important sediment sources that contributed to reservoir

Thresholds for gully initiation and sedimentation in Mediterranean Europe

In Mediterranean areas the dynamics of gully development act as an important indicator of desertification. However, little is known about the influence of climate and land-use changes, and almost no field data exist to assess the sensitivity

Testing the ephemeral gully erosion model (EGEM) for two Mediterranean environments

intensively cultivated land and abandoned land in southeast Portugal (Alentejo study area). Together with the assessment of all EGEM-input parameters, the actual eroded volume for each ephemeral gully was also determined in the field. The resulting

Mound development as an interaction of individual plants with soil, water erosion and sedimentation processes on slopes

. The influence of slope gradient, plant species and plant parameters on the shape and height of microtopographic studies is also studied. Main processes were identified as affecting mound development in the studied field site : sedimentation, differential

Decadal-scale analysis of ground movements in old landslides in western Belgium

their spatial and temporal distribution as well as the magnitude of the vertical and horizontal ground displacements. After field validation of the detected movements, they finally discuss their controlling factors. While most movements were triggered by intense

Effects of region-wide soil and water conservation in semi-arid areas : the case of northern Ethiopia

by approximately 68%, infiltration and spring discharge are enhanced and vegetation cover has improved. These impacts are evidenced and quantified by a comparison of the current landscape with a coverage of 30-year old photographs and substantiated by field

Soil losses due to potato and sugar beet harvesting in NE China

This study investigated soil loss due to crop harvesting (SLCH) for potato and sugar beet plots on farmer's fields spread over 4 regions in northeast China where harvesting is carried out by hand. The aims are to evaluate the impacts of possible

Channel width-flow discharge relationships for rills and gullies

In order to investigate the width-discharge relationships for rills and gullies, a new method is proposed based on field measurements of widths of concentrated-flow erosion channels both upstream and downstream of channel junctions. A total of 322

Medium-term evolution of a gully developed in a loess-derived soil

, which was not erased by subsequent tillage. Between June 1986 and December 1999, 8 field surveys were conducted to measure gully dimensions. Discussion of the results. Although this gully is located in a cultivated area, it became permanent due

Specific sediment yield in Tigray-Northern Ethiopia : assessment and semi-quantitative modelling

Sediment deposition in reservoirs is a serious off-site consequence of soil erosion in Tigray. Field rating of catchment characteristics and the sediment yield data from the reservoir survey were used for calibration and validation of the models

Spatially distributed data for erosion model calibration and validation : the Ganspoel and Kinderveld datasets

The AA. describe a dataset that offers possibilities for improved evaluation and parameterisation of spatially distributed soil erosion models. The dataset combines rainfall, runoff and sediment discharge data collected at the outlet and field

Measurements at one-year interval of rock-fragment fluxes by sheep trampling on degraded rocky slopes in the Mediterranean

Field experiment ; Greece ; Mediterranean area ; Sheep ; Slope ; Soil degradation ; Soil erosion ; Tracer ; Water erosion