Journal ArticleDOI
A model of two-phase bedload transport in an oregon coast range stream
W. L. Jackson,Robert L. Beschta +1 more
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TLDR
In this article, a descriptive model for bed material routing in small sand and gravel bedded channels with sequences of pools and armoured riffles was developed, and the model described bedload transport as occurring in two phases: Phase I involves the transport of fine, predominantly sand-sized bed materials over stable gravel-armoured riffles.Abstract:
A descriptive model for bed material routing in small sand and gravel bedded channels with sequences of pools and armoured riffles was developed. Aspects of the model are demonstrated at Flynn Creek, a 202-ha, third-order drainage in the Oregon Coast Range. Assuming that channel geometry, sediment transport competence, and the availability of sediments for transport are all non-uniform in the downstream direction, the model described bedload transport as occurring in two phases. Phase I involves the transport of fine, predominantly sand-sized bed materials over stable gravel-armoured riffles. Phase II occurs at higher flows that can entrain riffle armour and transport riffle sediments, in addition to Phase I sediments. Phase I bedload transport was sampled during three moderate flow events. A power function related Phase I bedload transport to water discharge. The relationship was consistent between storms and between two successive years. Phase II bedload transport, sampled during a 1.8-yr return period streamflow event in February, 1979, proved non-uniform in a downstream direction and unsteady over time at a given stream discharge. Transport rates closely correlated with the rapid scour and redeposition of the riffle at the bedload sampling cross-section; transport peaks corresponded to scour and transport decreased greatly during deposition. The transport of large (> 12.5 mm diam.) bed material increased up to 12-fold during riffle scour.read more
Citations
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A hierarchical framework for stream habitat classification: Viewing streams in a watershed context
TL;DR: In this article, the authors present a frame-work for a hierarchical classification system, entailed an organized view of spatial and temporal variation among and within stream systems, which is useful for research involving establishment of monitoring stations, determination of local impacts of land-use practices, generalization from site-specific data, and assessment of basinwide, cumulative impacts of human activities on streams and their biota.
Journal ArticleDOI
Channel-reach morphology in mountain drainage basins
TL;DR: In this article, a classification of channel-reach morphology in mountain drainage basins synthesizes stream morphologies into seven distinct reach types: colluvial, bedrock, and five alluvial channel types (cascade, step pool, plane bed, pool rime and dune ripple).
Journal ArticleDOI
Bed material transport and the morphology of alluvial river channels
TL;DR: In this article, the authors studied the relationship between sediment transport and river morphology by defining sediment transport regimes on the basis of the Shields number, a non-dimensional measure of the capacity of the channel to move sediment of a given caliber.
Journal ArticleDOI
Surface-based Fractional Transport Rates: Mobilization Thresholds and Partial Transport of a Sand-gravel Sediment
TL;DR: In this article, 28 coupled observations were made in a laboratory flume using a wide range of flows and a sediment with a very poorly sorted, bimodal grain size distribution.
Journal ArticleDOI
Sediment Transport and Resulting Deposition in Spawning Gravels, North Coastal California
TL;DR: In this article, the authors measured sedimentation of spawning gravel beds to sediment transport, infiltration of fine sediment into clean gravel beds, bed material size distributions, scour-fill depths, and sediment transport during 10 storm flow events were measured in three streams of north coastal California.
References
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Journal ArticleDOI
Areal Sorting of Bed-Load Material: The Hypothesis of Velocity Reversal
TL;DR: In this paper, the velocity reversal hypothesis was used to explain the areal sorting of channel material, i.e., relatively large material in riffles and finer material in pools.
Journal ArticleDOI
A Sorting Mechanism for a Riffle-Pool Sequence
TL;DR: Richards et al. as mentioned in this paper showed that the convergence of respective values of water-surface slope over a riffle and pool and the greater depth of the pool cause mean shear stress, τ = γRSE (where γ is the specific gravity of water, R is the hydraulic radius or approximately the mean depth, and SE is the energy gradient), to increase more rapidly at the pool (Leopold and others, 1964).
OtherDOI
Scour and fill in a stream channel, East Fork River, western Wyoming
TL;DR: In this paper, the East Fork River was studied during a spring flood and the authors found that the hydraulic geometry of every cross section deviated from the mean of the reach, and the associated sequence of scour and fill was a consequence of the deviation.
Journal ArticleDOI
SIMULATION OF SEDIMENT TRANSPORT AND ARMOURING / Simulation des transports solides et de l'armure du lit
James P. Bennett,Carl F. Nordin +1 more
TL;DR: In this paper, a model embodying these components has been developed for upland streams with tributaries, where streams are assumed to have a wash load, sand or gravel beds, and erosion resistant banks.
Journal ArticleDOI
Bedload transport in an Oregon Coast Range stream
TL;DR: In this paper, the authors measured bedload transport with two sampler types (vortex tube and Helley-Smith pressure differential) for three major storms at Flynn Creek, which drains a 2.2km2 forested watershed in the Oregon Coast Range.