Research ArticleSEDIMENTOLOGY

The exceptional sediment load of fine-grained dispersal systems: Example of the Yellow River, China

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Science Advances  12 May 2017:
Vol. 3, no. 5, e1603114
DOI: 10.1126/sciadv.1603114
  • Fig. 1 GSDs of sediment from both silty and sandy dispersal environments.

    (A) Comparison of GSDs for a range of sedimentary environments, including the Huanghe, where median sediment size ranges from silt to fine sand. The left-right arrow indicates the grain size range for which standard, physics-based transport formulae have been previously designed. The light brown bar indicates the grain size range that the formula presented here accounts for silt and very fine sand. Note that many natural sediment transport systems fall in the silt to very-fine sand range, for which no unifying sediment transport relation exists. (B) GSDs of suspended sediment and bed material, sampled at six gauging stations on the lower Huanghe (see fig. S1 for the locations of the gauging stations).

  • Fig. 2 GEH formula for the lower Huanghe sediment transport data and the universal formula for both fine-grained and sandy environments.

    (A) Data from the lower Huanghe collapse to a power law relation, similar to the EH formula, but with a significantly different coefficient α and power n. Note that the sediment transport rate in the lower Huanghe is about 15 times larger than that predicted by the original EH formula. (B) The coefficient α and the power n of GEH show an abrupt transition (light brown bar) as the grain size of bed material transits through the range of 130 to 190 μm. The error ranges denote the 95% confidence intervals for α and n. The complete form of the universal sediment transport relation can be found in Supplementary text. The red arrows show the median bed material grain sizes at Huayuankou (150 km downstream of Xiaolangdi Dam; see fig. S1) before and after the Xiaolangdi Dam construction. In addition to the dependence on grain size, the coefficient α and the power n may also have a weak dependence on Fr (see fig. S6). The adjusted values of coefficient α and the power n are based on the complete Guy-Simons-Richardson database (see Materials and Methods). (C) The grain size range where the abrupt transition (light brown bar) is seen coincides with the transition of sediment transport modes; within the grain size range of 130 to 190 μm, the sediment transport mode transitions from a range where the suspended load is dominant to a range where the substantial suspended load and bed load coexist. The black dashed line denotes the threshold of bed load dominance (u*/vs = 0.4), and the blue broken line denotes the threshold of suspended load dominance (u*/vs = 3). Here, u* is the shear velocity, and vs is the settling velocity of a sediment particle.

  • Fig. 3 Channel bed bathymetry data of the lower Huanghe and lower Mississippi River.

    (A) Bathymetric map of a straight reach of the lower Huanghe surveyed during the base flow period of 2016 (A-A′). (B) Bathymetric map of a straight reach of the lower Mississippi River (B-B′). (C) Relative bed variation along two longitudinal profiles, where x is the downstream distance from the survey origin point, Hb is the bed elevation, Embedded Image is the average bed elevation, Embedded Image is the average water depth, and Ld and Hd are the wavelength and wave height of dunes, respectively. (D) Comparison of long profiles of bed elevation between the Huanghe and the Mississippi River, illustrating the difference in bedform morphology. The A-A′ segment of the Huanghe bed profile shown here is taken from the zone defined by the blue rectangle in (C), whereas the C-C′ segment of Huanghe profile is taken from fig. S7B and corresponds to the flood season period of WSRS in 2015.

  • Fig. 4 Comparisons between the calculated dimensionless sediment flux based on the universal GEH formulation and data from two databases.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/5/e1603114/DC1

    Supplementary text

    table S1. Summary of hydraulic and grain size conditions of databases that were used for the development and validation of previous and present formulae.

    table S2. Sensitivity analysis of the GEH formulation to cutoff grain size.

    table S3. Comparisons between computed and measured sediment discharge in the Huanghe.

    fig. S1. Map of the Huanghe Basin and the Loess Plateau.

    fig. S2. Sediment concentration diagram.

    fig. S3. Schematic diagram of hydrodynamics over asymmetrical, angle-of-repose dunes.

    fig. S4. The lower Huanghe data and GEH formulae.

    fig. S5. Comparison between the Shields number due to skin friction and the Shields number due to boundary shear stress at Huayuankou and Lijin gauging stations, respectively.

    fig. S6. Dependence of the coefficient α and the power index n of the GEH on Fr.

    fig. S7. Channel bed bathymetry data of the lower Huanghe during the flood period of the 2015 WSRS.

    References (5668)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Text
    • table S1. Summary of hydraulic and grain size conditions of databases that were used for the development and validation of previous and present formulae.
    • table S2. Sensitivity analysis of the GEH formulation to cutoff grain size.
    • table S3. Comparisons between computed and measured sediment discharge in the Huanghe.
    • fig. S1. Map of the Huanghe Basin and the Loess Plateau.
    • fig. S2. Sediment concentration diagram.
    • fig. S3. Schematic diagram of hydrodynamics over asymmetrical, angle-of-repose dunes.
    • fig. S4. The lower Huanghe data and GEH formulae.
    • fig. S5. Comparison between the Shields number due to skin friction and the Shields number due to boundary shear stress at Huayuankou and Lijin gauging stations, respectively.
    • fig. S6. Dependence of the coefficient α and the power index n of the GEH on Fr.
    • fig. S7. Channel bed bathymetry data of the lower Huanghe during the flood period of the 2015 WSRS.
    • References (56–68)

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