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Variability of dry sediment bulk density between and within retention ponds and its impact on the calculation of sediment yields

Variability of dry sediment bulk density between and within retention ponds and its impact on the calculation of sediment yields
Belgium ; Grain size distribution ; Impact ; Organic materials ; Reservoir ; Sediment budget ; Sedimentology ; Soil erosion ; Watershed
The objectives of this study are to make an assessment of the variability in dry sediment bulk density (dbD) between and within small flood retention ponds in central Belgium and to look at the factors controlling this variability. It will further
be evaluated if the various existing dry sediment bulk density prediction techniques for large reservoirs can be used in another environment, i.e. small ponds, and what the implications of their use are for the calculation of sediment yield.

Modelling mean annual sediment yield using a distributed approach

Modelling mean annual sediment yield using a distributed approach
Analyse de régression ; Bassin-versant ; Belgique ; Bilan sédimentaire ; Charge en suspension ; Echelle spatiale ; Erosion des sols ; Leuven ; Modèle ; Taux de sédimentation ; Vlaanderen
Belgium ; Flanders ; Leuven ; Model ; Regression analysis ; Sediment budget ; Sedimentation rate ; Soil erosion ; Spatial scale ; Suspended load ; Watershed
The AA. present a spatially distributed model for the calculation of sediment delivery to river channels (SEDEM : SEdiment DElivery Model) at a catchment scale (100 to 10 000 km2). The model was applied on several catchments in central Belgium
for which medium-term sediment export measurements as well as spatially distributed data on topography, land use and soils are available.

Effects of rock fragment size and cover on overland flow hydraulics, local turbulence and sediment yield on an erodible soil surface

Effects of rock fragment size and cover on overland flow hydraulics, local turbulence and sediment yield on an erodible soil surface
Experimentation ; Rill wash ; Runoff ; Sediment budget ; Sediment transport ; Slope ; Soil erosion ; Turbulence
The interactions between overland flow hydraulics and sediment yield were studied in flume experiments on erodible soil surfaces covered by rock fragments. The high erodibility of a non-cohesive fine sediment permitted the effects of local
turbulence and scour on sediment yield to be examined. Overland flow hydraulics and sediment yield were compared for experiments with pebble and cobble rock fragment covers. An adjustment of existing scour formulas that predict scour around bridge piers
is suggested. Sediment yield from non-cohesive soils might then be estimated by a combination of sediment transport and scour formulas.

Evaluation of the simple setting theory for predicting sediment deposition by overland flow

Evaluation of the simple setting theory for predicting sediment deposition by overland flow
Belgium ; Experimentation ; Grain size distribution ; Model ; Runoff ; Sediment load ; Sediment transport ; Slope ; Slope gradient ; Suspended load
Experiments were conducted in the laboratory to evaluate the influence of sediment concentration, sediment grain-size distribution, bed slope and flow discharge on sediment deposition rates and patterns associated with a reduction in bed slope
. The experimental data clearly indicate that sediment deposition by overland flow is a very selective process. More specifically, this study investigates to what extent sediment deposition can be predicted using the simple settling theory for flows with a shear

Evaluation of the simple settling theory for predicting sediment deposition by overland flow

Evaluation of the simple settling theory for predicting sediment deposition by overland flow
Belgium ; Experimentation ; Grain size distribution ; Model ; Rill wash ; Sediment transport ; Slope gradient ; Soil erosion
Experiments were conducted in the laboratory to evaluate the influence of sediment concentration, sediment grain-size distribution, bed slope and flow discharge on sediment deposition rates and patterns associated with a reduction in bed slope. More
specifically, the study investigates to what extent sediment deposition (both total mass and sediment quality) can be predicted using the simple theory for flows with a shear stress below the threshold value, and which modelling approach can best be used once

Sediment export by water from an agricultural catchment in the Loam Belt of central Belgium

Sediment export by water from an agricultural catchment in the Loam Belt of central Belgium
Agroclimatology ; Belgium ; Grain size distribution ; Gully erosion ; Loam ; Precipitation ; Sediment budget ; Soil erosion ; Suspended load ; Water erosion ; Watershed
This paper reports the results of a study which was set up to examine the linkage between sediment export and within-basin processes in a small catchment in the Belgian Loam Belt. Sediment characteristics were monitored at the catchment outlet
. Furthermore, monthly surveys in the catchment were conducted to study various soil surface conditions and erosion and sedimentation patterns. The main objectives of this study are 1) to detect variations in sediment yield on different time-scales, and 2
) to relate the sediment yield at the outlet of the basin to processes within the catchment.

Factors controlling sediment yield from small intensively cultivated catchments in a temperate humid climate

Factors controlling sediment yield from small intensively cultivated catchments in a temperate humid climate
Belgium ; Cultivated land ; Model ; Multiple regression ; Sediment budget ; Soil erosion ; Temperate zone ; Watershed
Data on sediment yield from 26 small cultivated catchments (10-10 000 ha) in central Belgium were collected based on sedimentation rates in small flood retention ponds. Various catchment properties were analysed in order to understand the large
variation in observed sediment yield. A multiple regression model including 3 morphological catchment properties is a valuable tool to predict total sediment yield from catchments in central Belgium. This model has an efficiency of 0.81. The importance
of spatially distributed parameters within catchments are some of the major reasons that the proposed model does not explain all observed variation in sediment yield.

Characteristics of sediment deposits formed by intense rainfall events in small catchments in the Belgian Loam Belt

Characteristics of sediment deposits formed by intense rainfall events in small catchments in the Belgian Loam Belt
Belgium ; Grain size distribution ; Land use ; Loam ; Precipitation ; Sediment budget ; Sediment transport ; Soil erosion ; Spatial distribution ; Vegetation ; Water pollution ; Watershed
This paper discusses the results of 2 detailed field surveys, carried out after extreme rainfall events in springtime. The objectives are 1) to investigate to what extent the sediment delivery ratio of a catchment scale is controlled by the spatial
organisation of land use in the absence of spatial control measures, and 2) to compare the size characteristics of the deposited sediment with the size characteristics of the source soil material. Such information may be used to optimise the spatial
distribution of land-use in order to reduce sediment and pollutant delivery to streams.

Detachment and transportation of loose sediments by raindrop splash. Part 1. The calculation of absolute data on detachability and transportability

Detachment and transportation of loose sediments by raindrop splash. Part 1. The calculation of absolute data on detachability and transportability
Expériences en laboratoire sur la détachabilité et le transport de neuf sédiments meubles sur un bac d'essai de 100 20 cm avec un écran récepteur d'un mètre carré. Le modèle trigonométrique proposé est une expression du rapport du sédiment recueilli
sur l'écran à la masse totale projetée et de la relation entre la distance apparente de projection des poids de sédiments sur l'écran et la distance réelle de déplacement de tous les matériaux.

The nature of small-scale flooding, muddy floods and retention pond sedimentation in central Belgium

The nature of small-scale flooding, muddy floods and retention pond sedimentation in central Belgium
Belgium ; Economic cost ; Flood ; Inundation ; Land use ; Rill wash ; Rural area ; Sediment budget ; Soil erosion ; Topography ; Watershed
and the site in relation to topography and landuse. This study also focuses on the use of retention ponds as a control measure, the problem of siltation of the ponds and to their potential for estimating sediment yield.

Effects of horseshoe vortex erosion on sediment yield from soils covered by rock fragments

Effects of horseshoe vortex erosion on sediment yield from soils covered by rock fragments
Analyse en laboratoire des effets de différentes couvertures d'éléments grossiers sur l'hydraulique du ruissellement et l'érosion qu'il entraîne. La production de sédiments par le ruissellement lors de ces expériences a été très influencée par

Estimating trap efficiency of small reservoirs and ponds : methods and implications for the assessment of sediment yield

Estimating trap efficiency of small reservoirs and ponds : methods and implications for the assessment of sediment yield

Assessment of the interrill and rill contributions to total soil loss from an upland field plot

Présentation des résultats des mesures d'érosion du sol réalisées sur une parcelle expérimentale dans la région des limons, en Belgique. Comparaison des pertes de sédiments liées à l'érosion par ravinement dans les rigoles et au splash dans les

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