Self‐Limitation of Sand Storage in a Bedrock‐Canyon River Arising From the Interaction of Flow and Grain Size

Topping, David J.; Grams, Paul E.; Griffiths, Ronald E.; Dean, David J.; Wright, Scott A.; Unema, Joel

doi:10.1029/2020jf005565

Cited by 12 publications

(7 citation statements)

References 126 publications

(333 reference statements)

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“…Accurate estimation of sediment loads using discharge–sediment rating curves is possible if the variation about the curves is random or averages out over sufficiently long prediction intervals (Topping et al, 2021). In the Chippewa River, the presence of Type 3 and Type 1 hysteresis indicates that the Q ‐independent concentration/load variation about these curves is not random, but is rather caused by systematic changes in ( u * ) sf (driven by changes in dune form drag) and D B (driven by changes in sand supply).…”

Section: Discussionmentioning

confidence: 99%

“…Large variability in relations between water discharge ( Q ) and sand load typify most rivers (Gray & Simões, 2008). Sand transport is generally governed by processes that are at least partially decoupled from discharge, including changes in the sand supply, and changes in the boundary shear stress caused by bed scour and fill (Colby, 1964; Topping et al, 2021), and/or lags in bedform geometric adjustment. These processes can result in hysteresis in the transport of one or more size classes of sand in the suspended load and/or bedload (Topping et al, 2000; Wilbers & Ten Brinke, 2003).…”

Section: Background: Sand Transportmentioning

confidence: 99%

“…These curves, along with bed‐sediment grain‐size data, were utilized in the modified‐Einstein method (Colby & Hubbell, 1961) to estimate the total sediment load (i.e., sand, silt, and clay). These ratings‐based estimates likely contained large uncertainty (Topping et al, 2021). Although the suspended silt‐and‐clay load is non‐negligible, nearly all of the material dredged from lower Pool 4 is sand.…”

Section: Study Areamentioning

confidence: 99%

“…Accurately determining sediment loads is fundamental to river engineering and management (Auel & Boes, 2011; Chen, 1975; Dean et al, 2020; Erwin et al, 2012; Grams et al, 2020; Johnson et al, 2001; Mia & Nago, 2003; Topping et al, 2018, 2021). Despite its importance, accurate estimation of sediment loads remains difficult because sediment transport is driven by spatially variable, non‐linear physical processes (Asselman, 2000; Gray & Simões, 2008; McLean et al, 1999), which may be affected by a time‐varying sediment supply (Dean et al, 2020; Gomez, 2006; Rubin et al, 2020) and vegetation (Dean & Topping, 2019; Diehl et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

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The use of continuous sediment‐transport measurements to improve sand‐load estimates in a large sand‐bedded river: The lower Chippewa River, Wisconsin

Dean

Topping

Buscombe

et al. 2022

Earth Surf Processes Landf

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Accurately determining sediment loads is necessary for managing river environments but is difficult because multiple processes can lead to large discharge‐independent changes in sediment transport. Thus, estimations of sediment load using discharge–sediment rating curves fit to sparse or historical sediment‐transport measurements can be inaccurate, necessitating alternative approaches to reduce uncertainty. Continuous sediment‐transport measurements reduce uncertainty because they can be used to detect discharge‐independent changes in transport and are therefore unaffected by hysteresis. We used largely continuous approaches to measure sand transport in the lower Chippewa River, a large sand‐supplying tributary to the Mississippi River. We used side‐looking acoustic‐Doppler profilers to continuously measure suspended‐sand concentration, and bedform‐tracking techniques to episodically measure bedload transport. Bedload transport was then continuously estimated using a discharge‐dependent ratio of bedload to suspended‐sand transport. This approach allowed determination of sand loads that were not estimated based only on water discharge. Our continuous suspended‐sand measurements show that hysteresis between discharge and suspended‐sand concentration occurs during most floods. Quasi‐continuous bed‐elevation measurements using a scour monitor show that lags between discharge and dune geometric adjustment is also common, causing hysteresis between discharge and bedload transport during floods. Furthermore, comparisons of our measurements with historical sediment‐transport measurements indicate large discharge‐independent declines in both suspended‐sand and bedload transport since the 1980s. These findings indicate that sand transport is a non‐stationary function of water discharge over timescales ranging from within individual floods to decades. Consequently, although our continuous‐measurement approach yields only a ~20–30% improvement over rating‐curve estimates of sand load over multi‐year periods, our approach yields up to a factor‐of‐five improvement in sand‐load estimates over the shorter, within a flood timescales, over which the largest discharge‐independent changes in sand transport occur.

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Section: Discussionmentioning

confidence: 99%

Section: Background: Sand Transportmentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The use of continuous sediment‐transport measurements to improve sand‐load estimates in a large sand‐bedded river: The lower Chippewa River, Wisconsin

Dean

Topping

Buscombe

et al. 2022

Earth Surf Processes Landf

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“…After the closure of Glen Canyon Dam, sand supply limitation has led to substantial erosion of the bed and depletion of iconic and ecologically valuable sand bars (Rubin et al, 2002). During floods, tributaries like the Paria River still provide limited sand inputs, which travel down the Colorado River as an elongating sediment wave with a finer front (Topping et al, 2000(Topping et al, , 2021. Sediment travels in suspension as well as bedload with migrating dunes.…”

Section: The Colorado River Reachmentioning

confidence: 99%

Mapping 2‐D Bedload Rates Throughout a Sand‐Bed River Reach From High‐Resolution Acoustical Surveys of Migrating Bedforms

Coz

Perret

Camenen

et al. 2022

Water Resources Research

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Measuring bedload in sand-bed channels is important for a number of river and coastal management issues (e.g., sediment budget, channel stability, navigation, ecological habitat, coastal retreat) but it remains a challenging operation. Due to technical difficulties, cost, and field hazards, manual sampling techniques are often replaced by surrogate techniques such as dune-tracking from acoustical sounding of the bed topography. Bedform characteristics such as bedform height, wavelength, and velocity can be determined with reasonable accuracy, then used to determine bedload if two successive surveys of bed elevation are available. Based on the Exner equation for sediment continuity, the mean bedload rate q b over a bedform wave length can be expressed as (Simons et al., 1965):where p is the bedform porosity, V b is the bedform velocity, H b is the mean bedform height (thickness) and q b,0 is a constant bedload rate that may be interpreted as the transport rate below the bedform baseline (Simons et al., 1965) or as the fraction of bed material load that moves intermittently in near-bed suspension (McElroy & Mohrig, 2009). Traditionally, the mean bedform height is computed as H b = α b H b,max where H b,max is the crest-to-trough height of bedforms and α b is the bedform shape factor. Most often, dunes are assumed to be triangular in shape, hence α b = 0.5.A number of methods for determining bedform characteristics from a bed-elevation profile (or longitudinal transect) exist (see van der Mark & Blom, 2007 for a review). The detection of bedforms can be based on either manually selected crests and troughs, local extremes, or zero crossings in the detrended bed-elevation profile. These methods come with a variable degree of subjectivity, usually requiring some choices and thresholds to be set to avoid including smaller, superimposed bedforms or minor variations in the bed-elevation profile. Traditionally,

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Estimating catchment‐scale sediment storage in a large River Basin, Colorado River, USA

Kemper,

Knox,

Raffae

et al. 2024

River Research & Apps

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Catchment‐scale sediment storage is conceptualized as increasing in magnitude downstream, although reach‐scale controls may override this trend. We use empirical data from a literature review and two numerical models to quantitatively estimate sediment storage across the Colorado River Basin, USA. We use assumed alluvial thickness with floodplains delineated in the GFPLAIN model from 30 m digital elevation models. We use the SWAT+ model based on model‐estimated (i) groundwater storage and (ii) sediment storage. Existing studies indicate that sediment stored in floodplains and on low terraces is ~0.3–6 m thick. A first‐order approximation of volumetric storage capacity for natural floodplains is ~105 m3 per km. Sediment storage volumes of floodplains are ~108–1011 m3 over river lengths of 101–103 m. For the modeling estimates, we evaluated sediment storage by stream order and by elevation band within the Upper and Lower Colorado River Basins. Comparisons among the outputs cause us to place more confidence in the GFPLAIN and SWAT+ aquifer volume estimates. Each method includes substantial uncertainty and constitutes a first‐order approximation. Results suggest using 21 and 130 billion cubic meters as approximate lower and upper bounds for total sediment storage in the Upper Basin and 314 and 482 billion cubic meters as approximate lower and upper bounds for the Lower Basin. The largest proportion of sediment is stored in the montane and steppe zones in the Upper Basin and in the Sonoran zone in the Lower Basin.

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Self‐Limitation of Sand Storage in a Bedrock‐Canyon River Arising From the Interaction of Flow and Grain Size

Cited by 12 publications

References 126 publications

The use of continuous sediment‐transport measurements to improve sand‐load estimates in a large sand‐bedded river: The lower Chippewa River, Wisconsin

The use of continuous sediment‐transport measurements to improve sand‐load estimates in a large sand‐bedded river: The lower Chippewa River, Wisconsin

Mapping 2‐D Bedload Rates Throughout a Sand‐Bed River Reach From High‐Resolution Acoustical Surveys of Migrating Bedforms

Estimating catchment‐scale sediment storage in a large River Basin, Colorado River, USA

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