The non-layering of gravel streambeds under ephemeral flood regimes

Laronne, Jonathan B.; Reid, Ian; Yitshak, Yitshak; Frostick, Lynne E.

doi:10.1016/0022-1694(94)90266-6

Cited by 128 publications

(102 citation statements)

References 19 publications

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“…Sediment transport in ephemeral streams of arid regions often occurs in pulses during infrequent, large, storm events. The intense nature of these transport events is characterized by turbulent flows which transport material of many different sizes at similar rates (Laronne and Reid, 1993;Laronne et al, 1994;Reid and Laronne, 1995). These flows often infiltrate the channel after short distances; flow duration is insufficient to armor the bed or selectively transport finer grain sizes.…”

Section: Grain Sizementioning

confidence: 99%

Using 10Be and 26Al to determine sediment generation rates and identify sediment source areas in an arid region drainage basin

2002

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We measured 10 Be and 26 Al in 64 sediment and bedrock samples collected throughout the arid, 187 km 2 Yuma Wash drainage basin, southwestern Arizona. From the measurements, we determine long-term, time-integrated rates of upland sediment generation (81 F 5 g m À 2 year) and bedrock equivalent lowering (30 F 2 m Ma À 1 ) consistent with other estimates for regions of similar climate, lithology, and topography. In a small ( f 8 km 2 ), upland sub-basin, differences in nuclide concentrations between bedrock outcrops and hillslope colluvium suggest weathering of bedrock beneath a colluvial cover is a more significant source of sediment (40 Â 10 4 kg year) than weathering of exposed bedrock surfaces (10 Â 10 4 kg year). Mixing models constructed from nuclide concentrations of sediment reservoirs identify important sediment source areas. Hillslope colluvium is the dominant sediment source to the upper reaches of the sub-basin channel; channel cutting of alluvial terraces is the dominant source in the lower reaches. Similarities in nuclide concentrations of various sediment reservoirs indicate short sediment storage times ( < 10 3 years). Nuclide concentrations, measured in channel sediment from tributaries of Yuma Wash and in samples collected along the length of the Wash, were used to construct mixing models and determine sediment sources to the main stem channel. We find an exponential decrease in the channel nuclide concentrations with distance downstream, suggesting that as much as 40% of sediment discharged from Yuma Wash has been recycled from storage within basin fill alluvium. Sediment generation and denudation rates determined from the main stem are greater (25%) than rates determined from upland sub-basins suggesting that, currently, sediment may be exported from the basin more quickly than it is being generated in the uplands. Independence of nuclide concentration and sediment grain size indicates that channels transport sediment in discrete pulses before rapidly depositing poorly sorted material, suggesting that differences in transport times for different size materials are minimal. D

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Section: Grain Sizementioning

confidence: 99%

Using 10Be and 26Al to determine sediment generation rates and identify sediment source areas in an arid region drainage basin

2002

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“…This is part of a wider investigation of sediment transport processes in dryland ephemeral streams [Laronne and Reid, 1993;Laronne et al, 1994;Reid and Laronne, 1995;Reid et al, 1996Reid et al, , 1998b. The data have been collected using a permanently installed sediment transport monitoring station.…”

Section: Introductionmentioning

confidence: 99%

Evolution of bed load grain size distribution with increasing flow strength and the effect of flow duration on the caliber of bed load sediment yield in ephemeral gravel bed rivers

Powell¹,

Reid²,

Laronne³

2001

Water Resources Research

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121

113

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“…Transport formulae predict the theoretic transport capacity of the flow, which equals the transport rate absent of any general supply limitations (Bravo-Espinosa et al 2003). Typically, ephemeral channels in alluvial watersheds are assumed to be relatively sediment rich fluvial systems (Laronne et al 1994;Reid and Frostick 1997). Further, field observations during the study period never found any well established signs of sediment depletion (e.g., exposed bed rock, incision, scour).…”

Section: Discussionmentioning

confidence: 99%

“…A study by Yuill et al (2010) found that the coarser gravel patches remained relatively stable in size and location over time, despite the fact that patch grains were commonly mobilized by flow. As found in other dryland drainage networks (Laronne et al 1994), the channel bed shows no consistent trend of bed armoring or vertical stratification in mean grain size (Yuill 2010). Since Lucky Hills is a headwater watershed, its slopes and channel bed are the source of the vast majority of the fluvial sediment transport.…”

Section: Study Areamentioning

confidence: 99%

Predicting Coarse Sediment Transport from Patchy Beds in Ephemeral Channels

Yuill¹

2012

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Seven 1-D sediment transport formulae are employed to predict coarse sediment transport in a low-order, ephemeral channel with patchy bed material. Sediment transport is modeled through two different methods to characterize the sediment supply: by using a channel-averaged grain-size distribution (GSD) and by using the mean GSDs from the relatively coarse and fine textured patches that compose the channel bed.Modeling results show that the two different characterizations of the sediment supply produce significantly different values of predicted coarse sediment yield. The relative differences in the predicted yield values are dependent on the assumptions of each formula, including how the sediment supply is parameterized within the model. Modeled sediment yield values are contrasted to observed values for seven flashflood-type runoff events. The formulae accuracies typically are comparable to past analyses in fluvial systems more reminiscent of the hydraulic environments in which the models were derived (perennial flow, gravel-bed material).Study results reaffirm that the method by which sediment supply is characterized significantly impacts the performance of sediment transport formulae and that a single GSD might not adequately describe the sediment supply originating from patchy beds.

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The non-layering of gravel streambeds under ephemeral flood regimes

Cited by 128 publications

References 19 publications

Using 10Be and 26Al to determine sediment generation rates and identify sediment source areas in an arid region drainage basin

Using 10Be and 26Al to determine sediment generation rates and identify sediment source areas in an arid region drainage basin

Evolution of bed load grain size distribution with increasing flow strength and the effect of flow duration on the caliber of bed load sediment yield in ephemeral gravel bed rivers

Predicting Coarse Sediment Transport from Patchy Beds in Ephemeral Channels

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