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Coarse bed material patch evolution in low-order, ephemeral channels

Coarse bed material patch evolution in low-order, ephemeral channels
Arid area ; Arizona ; Ephemeral stream ; Grain size distribution ; River bed ; Sediment load ; Sediment transport ; Semi-arid area ; Stream ; United States of America
This paper documents the evolution of coarse bed material in Lucky Hills, a low-ordered, ephemeral watershed in southeast Arizona. The bed material is arranged in discrete patches that are differentiated from one another by their grain-size
distributions. Measurements of patch size (patch surface area) and composition (GSD) are recorded for a sample of coarse material patches throughout the study period, 2005-2006. The variability of patch size and GSD through time is used as a gauge of patch
stability. These measures of patch stability are then correlated to values of predicted grain mobility. Results indicate that relative stability varies from patch to patch, influenced by the balance of patch grains transported out of the patch
and the deposition of new grains into the patch.

Coarse sediment transport in mountain streams in Colorado and Wyoming, USA

Coarse sediment transport in mountain streams in Colorado and Wyoming, USA
Carrying capacity ; Colorado ; Fluvial dynamics ; Grain size distribution ; Mountain ; River bed ; Sediment load ; Stream ; Stream flow ; Typology ; United States of America ; Wyoming
where the AA. applied a piecewise regression model to relate flow to rates of bedload transport and to define phases of transport in coarse-grained channels. While there were many similarities in observed patterns of bedload transport at the 19 studied
The AA. use data from 19 sites to characterize patterns and rates of coarse sediment transport for a range of channel types and sizes, including step-pool, plane-bed, pool-riffle, and near-braided channels. This effort builds upon previous work
sites, each had its own bedload signal in that the rate and size of materials transported largely reflected the nature of flow and sediment particular to that system.

Simulations demonstrating interaction between coarse and fine sediment loads in rain-impacted flow

Simulations demonstrating interaction between coarse and fine sediment loads in rain-impacted flow
Grain size distribution ; Runoff ; Sediment load ; Sediment transport ; Simulation ; Soil erosion ; Splash
detached material. Coarse particles tend to be transported by RIFT, while fine particles tend to be transported without any assistance from raindrop impact. Simulations were performed by modelling the uplift and downstream movement of both fine and coarse

Identifying depositional and pedogenetic controls of Late Pleistocene loess-paleosol sequences (Saxony, Germany) by combined grain size and microscopic analyses

Identifying depositional and pedogenetic controls of Late Pleistocene loess-paleosol sequences (Saxony, Germany) by combined grain size and microscopic analyses
Germany ; Grain size distribution ; Loess ; Mineralogy ; Palaeo-environment ; Palaeosol ; Pedogenesis ; Periglacial features ; Saxony ; Upper Pleistocene ; Weichselian
analysis was conducted by classical pipette and sieve procedures and 8 grain size classes were distinguished. Generally, it was observed that an increase of coarse material is linked to an increase of the minerogenic components which can be attributed
to slope surface processes. When studying coarse grain size fractions by microscopic analysis, it is possible to differentiate between loessic layers formed by periglacial slope processes and layers overprinted by pedogenetic processes based on determining
The AA. demonstrate how combining high-resolution grain size and microscopic analyses can be used to discriminate depositional and pedogenetic features of Late Pleistocene loess-paleosol sequences (LPS) from the Saxonian Loess Region. Grain size
the nature and roundness of minerals. The results reveal similar temporal and lithogenetic pattern of Weichselian eolian dynamics of the study area and other records from the European continent. Furthermore, lithogenetic interpretations based on grain size

The use of acoustic imaging to reveal fossil fluvial systems - a case study from the southwestern Sea of Galilee

Alluvial cone ; Bathymetry ; Geophysics ; Grain size distribution ; Israel ; Palaeogeography ; Quaternary ; Sedimentation ; Seismic reflection
As a case study, a shallow geophysical survey using a Chirp profiler was conducted in the southwestern part of the Sea of Galilee. By correlating the seismic and core data the AA. found that areas with good seismic penetration represent coarse
clastics, while poor seismic penetration is related to fine clays. New detailed bathymetric mapping and bottom morphology images combined with the penetration characteristics of the Chirp signal reveal a large alluvial fan consisting mainly of coarse
material (sand to pebbles).

Flow and particle paths at a natural river confluence with coarse bed material

Flow and particle paths at a natural river confluence with coarse bed material
This paper reports on an experiment conducted at a natural channel confluence (Ruisseau du Sud and Eaton North River) with coarse bed material. The main objective of the experiment was to describe flow and sediment transport patterns.

Les vertisols des îles Canaries occidentales. Etude physico-chimique, minéralogique et micromorphologique

. Swelling and drying leads to translocation of soil material in the cracks from the top soil to the lower (B), to strong compaction and orientation of clay minerals and to grinding of coarse grains and fragments. Clay illuviation is important in all
Vertic matrix originates from basalt or lapillis. Illuviation of swelling clay in cracks of the weakly weathered basalt or between the glass grains breaks the basalt or presses the glass. Next basalt fragments are dispersed in the vertic matrix
where they are slowly smashed, weathering being parallel to this smashing, or already deformed glass grains are integrated with pressure into the matrix. Colluviation is very strong in these vertisols and masks the origin of the matrix in most soils

Origin of reversible cementation and brittleness of the fragipan horizon in Albeluvisols of the Carpathian Foothills, Poland

coatings and clay infillings indicating translocation of colloidal clay and iron oxides from overlying horizons. In addition, bridges between coarse grains of the soil material occur. It is highlighted that swelling clays are responsible for reversible
composition of bridges linking coarse soil material. Quantitative X-ray diffraction shows that the studied fragipan horizon contains high concentration of swelling clay minerals. Soil material from the fragipan horizon exhibits numerous clay and iron-clay

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
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
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

GENESIS OF BROWN, PODZOLIC, AND BOG-PODZOLIC SOILS ON COARSE-TEXTURED PARENT MATERIALS

GENESIS OF BROWN, PODZOLIC, AND BOG-PODZOLIC SOILS ON COARSE-TEXTURED PARENT MATERIALS
PROFONDE ET LES SOLS PODZOLIQUES SONT PERIODIQUEMENT EXCESSIVEMENT HUMECTES. LA COULEUR BLANCHATRE DE L'HORIZON A EST LIEE PRINCIPALEMENT A LA PERTE PAR LES GRAINS DE SABLE DE LEURS FILMS D'HYDROXYDE DE FER. LA PODZOLISATION SUR LES MATERIAUX A TEXTURE

Profile form and channel gradient variation within an upland drainage basin - River Noe, Derbyshire

Carrying capacity ; Derbyshire ; Discharge ; England ; Flood ; Grain size distribution ; Longitudinal section ; Precipitation ; Sediment load ; Stream ; United Kingdom ; Watershed
respond rapidly to rainfall events of even moderate magnitude. Consequently bed material transport occurs relatively frequently. Sediment transport is thus an active process, especially but not exclusively in the upper reaches. However, given
the coarseness of the load, amounts of sediment transport are likely to be small, even during flood flows.

Hydraulic geometry and changes in flow velocity at a river confluence with coarse bed material

Hydraulic geometry and changes in flow velocity at a river confluence with coarse bed material

The Ability of debris, heavily freighted with coarse clastic materials, to flow on gentle slopes

The Ability of debris, heavily freighted with coarse clastic materials, to flow on gentle slopes

Derivation of the probability density function of certain biased samples of coarse riverbed material

Derivation of the probability density function of certain biased samples of coarse riverbed material

Effect of grain diameter and packing condition on the avalanching depth on a slope composed of dry granular materials

Effect of grain diameter and packing condition on the avalanching depth on a slope composed of dry granular materials
Experimentation ; Grain size distribution ; Honshu ; Japan ; Mass movement ; Slope ; Slope dynamics
To examine the depth of avalanching taking place on a slope at a critical angle of repose, tilting tests were performed in the laboratory using slopes made of granular materials such as gravels and glass beads. The AA. conclude that the avalanche
depth on slopes made of granular materials is determined by the diameter of the slope materials and by their packing state.

CryoGRID 1.0 : Permafrost distribution in Norway estimated by a spatial numerical model

that permafrost underlies sites mainly with exposed bedrock or covered by coarse-grained sediments, such as blockfields and coarse tills. In northern Norway, palsa mires are abundant and organic material and vegetation strongly influence the ground thermal regime

The Pebble Transmitter System (PETS) : first results of a technique for studying coarse material erosion, transport and deposition

The Pebble Transmitter System (PETS) : first results of a technique for studying coarse material erosion, transport and deposition
to follow the tracered material even in large rivers and after several floods, or to monitor the movement of single particles or a small number of particles in great detail.

Grain-size analysis of surface material under wind erosion using the effective surface concept

Grain-size analysis of surface material under wind erosion using the effective surface concept
Aeolian features ; Aeolian transport ; Concept ; Experimentation ; Grain size distribution ; Methodology ; Roughness ; Wind erosion
This paper deals with the temporal variation in the grain size of surface material using an analytical method based on the effective surface concept. This method is applied to data collected in 2 series of wind tunnel experiments. The results
are compared with findings of other studies on aeolian sediment transport rate for individual grain size classes over time.

Centrifuge modelling of hillslope debris flow initiation

Geotechnics ; Grain size distribution ; Landslide ; Modelling ; Natural hazards ; Porosity ; Scotland ; Slope gradient ; Soil water ; United Kingdom
on slopes with coarse grained bedrocks can be partially explained in terms of lower critical pore pressure failure thresholds amongst the sandier soil matrixes produced from such lithologies. Differences in rates of water ingress into the model soils
The tests were carried out on model slopes consisting of soils with known properties prepared with constant initial density and material thickness. The results showed that soils with a higher silt fraction can sustain a higher increase in pore water

The effects of kinetic sorting on sediment mobility on steep slopes

Earth surface processes ; Experimentation ; Grain size distribution ; Kinetic sorting ; Mountain ; Sediment load ; Sediment transport ; Shear stress ; Slope gradient ; Stream
, and with different transport stages of the coarse fraction. Both runs produced an efficient transfer downstream of the injected material, but with a major difference : the first run (no kinetic sorting) produced permanent armour figuring clusters; the second run
(with kinetic sorting) also produced bed armouring, but this armour was periodically totally destroyed, leading to substantial bed erosion. The consequence is that fine materials are hidden to the flow during aggradation, allowing the slope to attain values much

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