Armoring and Sorting Simulation in Alluvial Rivers

Karim, M. Fazle; Holly, Forrest M.

doi:10.1061/(asce)0733-9429(1986)112:8(705)

Cited by 38 publications

(16 citation statements)

References 3 publications

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“…The error in prediction sometimes becomes unacceptable in gravel-bed rivers where the measured transport rates often differ by one to two orders of magnitude from predictions using the standard formulae (Bathurst, 2007;Barry et al, 2004). One of the major obstacles is the poor understanding of the degree to which a river-bed is coarsened or armored (Wilcock and DeTemple, 2005;Barry et al, 2004;Karim and Holly, 1986;Wu et al, 2004). In a mixed-size gravel-bed river, the bed is often sorted such that the surface composition is coarser than the substrate (Whiting and King, 2003;Wilcock and Crowe, 2003;Parker and Sutherland, 1990;Parker, 1990).…”

Section: Introductionmentioning

confidence: 99%

Understanding partial bed-load transport: Experiments and stochastic model analysis

Sun

Chen

Zhang

et al. 2015

Journal of Hydrology

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s u m m a r yThe complex dynamics of partial bed-load transport in a series of well-controlled laboratory experiments are explored systematically and simulated by a stochastic model in this study. Flume experiments show that the leading front of bed-load on a 20-m-long, mixed-size gravel-bed moves anomalously, where the transient transport rate of the accelerating front varies with the observation time scale. In addition, observations show that moving particles may experience bimodal transport (i.e., coexistence of long trapping time and large jump length) related to bed coarsening and the formation of clusters on a heterogeneous gravel-bed, which is distinguished from the traditional theory of hiding-exposing interactions among mixed-size particles. A fractional derivative model is finally applied to characterize the overall behavior of partial bed-load transport, including the coexistence of the sub-diffusion and non-local feature caused by turbulence and the micro-relief within an armor layer.

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Section: Introductionmentioning

confidence: 99%

Understanding partial bed-load transport: Experiments and stochastic model analysis

Sun

Chen

Zhang

et al. 2015

Journal of Hydrology

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“…Continuous depletion of suspendable sediment in the active layer will eventually reduce the erosion rate to zero. At this point, the active layer is composed entirely of non-suspendable sediment, and the sediment bed has become armored (Karim and Holly 1986, Jain and Park 1989, van Niekerk et al 1992). …”

Section: Non-cohesive Resuspension Processesmentioning

confidence: 99%

“…The bed armoring process is modeled by assuming that the sediment bed is composed of an active layer, which interacts with the water column, and a parent bed, which is below the active layer (Karim andHolly 1986, van Niekerk et al 1992). Interactions between the parent bed, active layer and water column cause the grain size distributions in the active layer and parent bed to change with time.…”

Section: Non-cohesive Resuspension Processesmentioning

confidence: 99%

“…Tracking temporal and spatial changes of class 1 and 2 volumes in the active and parent bed layers is accomplished using the bed model proposed by Karim and Holly (1986). The two-layer bed model conserves mass, with deposition and resuspension fluxes at the sediment-water interface being the only gain or loss mechanism for the non-cohesive bed.…”

Section: Non-cohesive Resuspension Processesmentioning

confidence: 99%

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Improvement of Sediment Transport Dynamics in HSPF

Ziegler¹,

Owen²

2002

proc water environ fed

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A widely used watershed model (HSPF) can simulate in-channel transport of suspended sediments. The formulations used to calculate sediment transport in HSPF may not always provide an accurate representation of resuspension and deposition processes, particularly for cohesive sediments. Cohesive and non-cohesive sediment dynamics used in a sophisticated sediment transport model (SEDZL) have been included in a modified version of HSPF. This modification significantly improves the in-channel sediment transport capabilities of HSPF. Important processes included in the modified model are: flocculation, probability of deposition and bed armoring.

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“…Major increases of bed sediment sizes had been reported within sand-bed reaches, dominated by sediments of 100-200 mm being converted to coarse-sand and gravel-bed reaches (Petts 1984). Karim et al (1983) developed a one-dimensional approach for bed armouring in alluvial channels, and Karim and Holly (1986) applied this approach to simulate 20 years of bed degradation in the Missouri River downstream of Gavins Point Dam. The research result shows good agreement with the observed bed characteristics.…”

Section: Introductionmentioning

confidence: 99%