Sediment-transport during three controlled-flood experiments on the Colorado River downstream from Glen Canyon Dam, with implications for eddy-sandbar deposition in Grand Canyon National Park

Topping, David J.; Rubin, David M.; Grams, Paul E.; Griffiths, Ronald E.; Sabol, Thomas A.; Voichick, Nicholas; Tusso, Robert B.; Vanaman, Karen M.; McDonald, Richard R.

doi:10.3133/ofr20101128

Cited by 31 publications

(87 citation statements)

References 25 publications

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“…Considering the relative importance of all of these sources of uncertainty, Topping et al . [] assigned uncertainties of 5, 10, and 50% to the sand loads on the main‐stem gages, tributary gages, and ungaged tributaries, respectively. Because these uncertainties represent the potential maximum magnitudes of persistent biases that are believed to possibly exist in the measurements, these uncertainties accumulate over time as per equation .…”

Section: Methodsmentioning

confidence: 99%

“…Using the formulation of Rubin and Topping [, ] and Topping et al . [],

C_{normals} \propto u_{*}^{3.5} D_{normalb}^{- 2.5} A_{normals}

where u * is shear velocity (a measure of flow strength), D b is the median grain size of the suspendable bed sediment, and A s is a fractional measure of the amount of the suspendable sediment covering the bed. Flow strength and grain size are related nonlinearly with concentration while the relation between supply and concentration is linear.…”

Section: Uncertainty and Bias In Sediment Budget Computationsmentioning

confidence: 99%

“…This suggests that the sand budget for much of the Colorado River in Grand Canyon is essentially indeterminate over multi‐year time scales. Sand accumulation may occur in years with average or larger tributary inputs and average or lower dam release volumes, but sand depletion is likely in other years and over timescales in excess of decades [ Topping et al ., ].…”

Section: Introductionmentioning

confidence: 99%

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Linking morphodynamic response with sediment mass balance on the Colorado River in Marble Canyon: Issues of scale, geomorphic setting, and sampling design

et al. 2013

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[1] Measurements of morphologic change are often used to infer sediment mass balance. Such measurements may, however, result in gross errors when morphologic changes over short reaches are extrapolated to predict changes in sediment mass balance for long river segments. This issue is investigated by examination of morphologic change and sediment influx and efflux for a 100 km segment of the Colorado River in Grand Canyon, Arizona. For each of four monitoring intervals within a 7 year study period, the direction of sandstorage response within short morphologic monitoring reaches was consistent with the flux-based sand mass balance. Both budgeting methods indicate that sand storage was stable or increased during the 7 year period. Extrapolation of the morphologic measurements outside the monitoring reaches does not, however, provide a reasonable estimate of the magnitude of sand-storage change for the 100 km study area. Extrapolation results in large errors, because there is large local variation in site behavior driven by interactions between the flow and local bed topography. During the same flow regime and reach-average sediment supply, some locations accumulate sand while others evacuate sand. The interaction of local hydraulics with local channel geometry exerts more control on local morphodynamic response than sand supply over an encompassing river segment. Changes in the upstream supply of sand modify bed responses but typically do not completely offset the effect of local hydraulics. Thus, accurate sediment budgets for long river segments inferred from reach-scale morphologic measurements must incorporate the effect of local hydraulics in a sampling design or avoid extrapolation altogether.Citation: Grams, P. E., D. J. Topping, J. C. Schmidt, J. E. Hazel Jr., and M. Kaplinski (2013), Linking morphodynamic response with sediment mass balance on the Colorado River in Marble Canyon: Issues of scale, geomorphic setting, and sampling design,

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Section: Methodsmentioning

confidence: 99%

“…Using the formulation of Rubin and Topping [, ] and Topping et al . [],

C_{normals} \propto u_{*}^{3.5} D_{normalb}^{- 2.5} A_{normals}

Section: Uncertainty and Bias In Sediment Budget Computationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Linking morphodynamic response with sediment mass balance on the Colorado River in Marble Canyon: Issues of scale, geomorphic setting, and sampling design

et al. 2013

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“…Using the modified formulation of Rubin and Topping [, ] in Topping et al [], suspended‐sediment concentration ( C s ) is dependent upon the reach‐scale hydraulics, and the reach‐scale amount and grain size distribution of sediment available for transport on the channel bed. Thus,

C_{s} \propto {u_{*}}^{3.5} {D_{normalb}}^{- 2.5} A_{s}

where u * is the shear velocity (a measure of the flow strength), D b is the reach‐averaged median grain size of suspendable bed sediment, and A s is the reach‐averaged fraction of the bed covered by the sediment with median grain size D b .…”

Section: Physics‐based Context For Predicting Patterns In Suspended‐smentioning

confidence: 99%

“…The amount of sediment available for suspended‐sediment transport in a reach is not directly determined by the total volume of suspendable sediment stored in the bed but, rather, is determined by D b and A s on the bed surface [ Topping et al , , ]. At the reach scale, A s and the volume of suspendable bed sediment should typically be positively correlated in alluvial rivers.…”

Section: Physics‐based Context For Predicting Patterns In Suspended‐smentioning

confidence: 99%

Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads

et al. 2016

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The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, undergoes rapid geomorphic changes as a result of its large sediment supply and variable hydrology; thus, it is a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling alluvial channel change. We analyzed a suite of sediment transport and geomorphic data to determine the cumulative influence of different flood types on changing channel form. In this study, physically based analyses suggest that channel change in the Rio Grande is controlled by both changes in flow strength and sediment supply over different spatial and temporal scales. Channel narrowing is primarily caused by substantial deposition of sediment supplied to the Rio Grande during tributary‐sourced flash floods. Tributary floods have large suspended‐sediment concentrations, occur for short durations, and attenuate rapidly downstream in the Rio Grande, depositing much of their sediment in downstream reaches. Long‐duration floods on the mainstem have the capacity to enlarge the Rio Grande, and these floods, released from upstream dams, can either erode or deposit sediment in the Rio Grande depending upon the antecedent in‐channel sediment supply and the magnitude and duration of the flood. Geomorphic and sediment transport analyses show that the locations and rates of sand erosion and deposition during long‐duration floods are most strongly controlled by spatial changes in flow strength, largely through changes in channel slope. However, spatial differences in the in‐channel sediment supply regulate sediment evacuation or accumulation over time in long reaches (greater than a kilometer).

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Characterizing riverbed sediment using high-frequency acoustics: 2. Scattering signatures of Colorado River bed sediment in Marble and Grand Canyons

Buscombe

Grams

Kaplinski

2014

J. Geophys. Res. Earth Surf.

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In this, the second of a pair of papers on the statistical signatures of riverbed sediment in high‐frequency acoustic backscatter, spatially explicit maps of the stochastic geometries (length and amplitude scales) of backscatter are related to patches of riverbed surfaces composed of known sediment types, as determined by georeferenced underwater video observations. Statistics of backscatter magnitudes alone are found to be poor discriminators between sediment types. However, the variance of the power spectrum and the intercept and slope from a power law spectral form (termed the spectral strength and exponent, respectively) successfully discriminate between sediment types. A decision tree approach was able to classify spatially heterogeneous patches of homogeneous sands, gravels (and sand‐gravel mixtures), and cobbles/boulders with 95, 88, and 91% accuracy, respectively. Application to sites outside the calibration and surveys made at calibration sites at different times were plausible based on observations from underwater video. Analysis of decision trees built with different training data sets suggested that the spectral exponent was consistently the most important variable in the classification. In the absence of theory concerning how spatially variable sediment surfaces scatter high‐frequency sound, the primary advantage of this data‐driven approach to classify bed sediment over alternatives is that spectral methods have well‐understood properties and make no assumptions about the distributional form of the fluctuating component of backscatter over small spatial scales.

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Sediment-transport during three controlled-flood experiments on the Colorado River downstream from Glen Canyon Dam, with implications for eddy-sandbar deposition in Grand Canyon National Park

Cited by 31 publications

References 25 publications

Linking morphodynamic response with sediment mass balance on the Colorado River in Marble Canyon: Issues of scale, geomorphic setting, and sampling design

Linking morphodynamic response with sediment mass balance on the Colorado River in Marble Canyon: Issues of scale, geomorphic setting, and sampling design

Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads

Characterizing riverbed sediment using high-frequency acoustics: 2. Scattering signatures of Colorado River bed sediment in Marble and Grand Canyons

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