Detachment of Undisturbed Soil by Shallow Flow

Zhang, Guanghui; Liu, Baoyuan; Liu, Guobin; He, Xiao-Song; Nearing, M. A.

doi:10.2136/sssaj2003.0713

Cited by 112 publications

(137 citation statements)

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“…These parameters are frequently used in predicting sediment concentration. Zhang et al (2003) found a linear function between flow velocity and sediment transport. For a given shear stress, detachment rate by shallow flow is primarily associated with flow regime (Nearing and Parker, 1994).…”

Section: Introductionmentioning

confidence: 94%

Hydraulic characteristics and sediment generation on slope erosion in the Three Gorges Reservoir Area, China

Feng

Cheng

Ding

et al. 2016

Journal of Hydrology and Hydromechanics

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Hydrological processes play important roles in soil erosion processes of the hillslopes. This study was conducted to investigate the hydrological processes and the associated erosional responses on the purple soil slope. Based on a comprehensive survey of the Wangjiaqiao watershed in the Three Gorges Reservoir, four typical slope gradients (5°, 10°, 15°and 20°) were applied to five rainfall intensities (0.6, 1.1, 1.61, 2.12 and 2.54 mm·min -1 ). The results showed that both surface and subsurface runoff varied greatly depending on the rainfall intensity and slope gradient. Surface runoff volume was 48.1 to 280.1 times of that for subsurface runoff. The critical slope gradient was about 10°. The sediment yield rate increased with increases in both rainfall intensity and slope gradient, while the effect of rainfall intensity on the sediment yield rate was greater than slope gradient. There was a good linear relationship between sediment yield rate and Reynolds numbers, flow velocity and stream power, while Froude numbers, Darcy-Weisbach and Manning friction coefficients were not good hydraulic indicators of the sediment yield rate of purple soil erosion. Among the three good indicators (Re, v and w), stream power was the best predictor of sediment yield rate (R 2 = 0.884). Finally, based on the power regression relationship between sediment yield rate, runoff rate, slope gradient and rainfall intensity, an erosion model was proposed to predict the purple soil erosion (R 2 = 0.897). The results can help us to understand the relationship between flow hydraulics and sediment generation of slope erosion and offer useful data for the building of erosion model in purple soil.

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Section: Introductionmentioning

confidence: 94%

Hydraulic characteristics and sediment generation on slope erosion in the Three Gorges Reservoir Area, China

Feng

Cheng

Ding

et al. 2016

Journal of Hydrology and Hydromechanics

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“…Flow discharge and slope gradient were commonly used to calculate soil detachment rate and transport capacity (Beasley and Huggins, 1982;Julien and Simons, 1985;Zhang et al, 2002Zhang et al, , 2003Zhang et al, , 2008Zhang et al, , 2009. Soil detachment rate and transport capacity increase as a power function of either fl ow discharge or slope gradient.…”

Section: Introductionmentioning

confidence: 99%

“…Some studies indicated that soil detachment rate in rills could be predicted well by shear stress, stream power, or unit length shear force (Nearing et al, 1991(Nearing et al, , 1999Elliot and Lafl en, 1993;Gimenez and Govers, 2002;Zhang et al, 2003). However, other studies showed that unit stream power was the best variable to compute soil detachment in rills (Yang, 1972;Govers, 1990Govers, , 1992Shih and Yang, 2009).…”

Section: Introductionmentioning

confidence: 99%

Effects of sediment load on hydraulics of overland flow on steep slopes

Zhang

Shen

Luo

et al. 2010

Earth Surf Processes Landf

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Eroded sediment may have signifi cant effects on the hydraulics of overland fl ow, but few studies have been performed to quantify these effects on steep slopes. This study investigated the potential effects of sediment load on Reynolds number, Froude number, fl ow depth, mean velocity, Darcy-Weisbach friction coeffi cient, shear stress, stream power, and unit stream power of overland fl ow in a sand-glued hydraulic fl ume under a wide range of hydraulic conditions and sediment loads. Slope gradients were varied from 8·7 to 34·2%, unit fl ow rates from 0·66 to 5·26 × 10 −3 m 2 s −1, and sediment loads from 0 to 6·95 kg m. Both Reynolds number (Re) and Froude number (Fr) decreased as sediment load increased, implying a decrease in fl ow turbulence. This inverse relationship should be considered in modeling soil erosion processes. Flow depth increased as sediment load increased with a mean value of 1·227 mm, caused by an increase in volume of sediment-laden fl ow (contribution 62·4%) and a decrease in mean fl ow velocity (contribution 37·6%). The mean fl ow velocity decreased by up to 0·071 m s −1 as sediment load increased. The Darcy-Weisbach friction coeffi cient (f) increased with sediment load, showing that the total energy consumption increased with sediment load. The effects of sediment load on f depended on fl ow discharge: as fl ow discharge increased, the infl uence of sediment load on f decreased due to increased fl ow depth and reduced relative roughness. Flow shear stress and stream power increased with sediment load, on average, by 80·5% and 60·2%, respectively; however, unit stream power decreased by an average of 11·1% as sediment load increased. Further studies are needed to extend and apply the insights obtained under these controlled conditions to real-world overland fl ow conditions.

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“…In fact, as nearly all RS test plots received the same rainfall intensity (i), interrill erodibility is proportional to SY, that is K i ¼ SY/i. Conceptually for bare or untreated soils, erodibility is only soil dependent, however erosion rate also depends on slope (S) and runoff rate (q R ) or stream power (P ¼ Sq R ); some have suggested that soil detachment is better described by power forms of P in which S and q R are raised to powers of approximately 2 and 1Á3, respectively (Zhang et al, 2002(Zhang et al, , 2003. Here, we consider the effects of q R (or infiltration rate) and slope on SY independently after first examining the strength of the correlation between SC and SY for the different soils.…”

Section: Resultsmentioning

confidence: 99%

Runoff sediment particle sizes associated with soil erosion in the Lake Tahoe Basin, USA

2008

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Runoff sediment from disturbed soils in the Lake Tahoe Basin has resulted in light scattering, accumulation of nutrients, and subsequent loss in lake clarity. Little quantified information about erosion rates and runoff particle-size distributions (PSDs) exists for determining stream and lake loading associated with land management. Building on previous studies using rainfall simulation (RS) techniques for quantifying infiltration, runoff, and erosion rates, we determine the dependence and significance of runoff sediment PSDs and sediment yield (SY, or erodibility) on slope and compare these relationships between erosion control treatments (e.g., mulch covers, compost, or woodchip incorporation, plantings) with bare and undisturbed, or 'native' forest soils. We used simulated rainfall rates of 60-100 mm h À1 applied over replicated 0Á64 m 2 plots. Measured parameters included time to runoff (s), infiltration and runoff rates (mm h À1 ), SY (g mm À1 runoff), and average sediment concentration (SC, g L À1 ) as well as PSDs in runoff samples. In terms of significant relationships, granitic soils had larger particle sizes than volcanic soils in bulk soil and runoff samples. Consequently, runoff rates, SCs, and SYs were greater from bare volcanic as compared to that from bare granitic soils at similar slopes. Generally, runoff rates increased with increasing slope on bare soils, while infiltration rates decreased. Similarly, SY increased with slope for both soil types, though SYs from volcanic soils are three to four times larger than that from granitic soils. As SY increased, smaller particle sizes are observed in runoff for all soil conditions and particle sizes decreased with increasing slope.

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Detachment of Undisturbed Soil by Shallow Flow

Cited by 112 publications

References 1 publication

Hydraulic characteristics and sediment generation on slope erosion in the Three Gorges Reservoir Area, China

Hydraulic characteristics and sediment generation on slope erosion in the Three Gorges Reservoir Area, China

Effects of sediment load on hydraulics of overland flow on steep slopes

Runoff sediment particle sizes associated with soil erosion in the Lake Tahoe Basin, USA

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