Effect of Grass Coverage on the Sediment Concentration in Overland Flow in the Hillslope-Gully Side Erosion System

Li, Mian; Yao, Wen Yi; Yang, Er; Chen, Jiang Nan; Ding, Wen Feng

doi:10.4028/www.scientific.net/amm.212-213.50

Cited by 2 publications

(2 citation statements)

References 3 publications

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“…Fr was subcritical flow on the 5 • slope. This result agrees with Pan and Shangguan [39], Li et al [40], and Zhang and Hu [17], who all indicated that the flow regime of overland flow on sloped grass plots was laminar. In contrast, as slope gradient increased, the flow regime of overland flow shifted from laminar and subcritical flow to laminar and supercritical flow, suggesting that in our study slope gradient had a greater influence on flow regime than vegetation cover.…”

Section: Effects Of Vegetation Cover and Slope Gradient On Runoff Hydsupporting

confidence: 90%

Relationships between Riparian Vegetation Pattern and the Hydraulic Characteristics of Upslope Runoff

Zhao

Zhang

et al. 2019

Sustainability

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Riparian vegetation plays a vital role in inhibiting soil and water loss, but few studies have quantified the relationships between vegetation spatial pattern and the hydraulic characteristics of upslope runoff. This study investigated how hydraulic characteristics (e.g., runoff coefficient, flow regime, flow resistance, and flow shear stress of overland flow) responded to differences in vegetation cover (15% and 30%), slope gradient (5°, 10°, 15°, and 20°), and vegetation pattern in the riparian zone along the lower Yellow River, China, based on landscape pattern analysis and a runoff scouring experiment with flow rates of 9 and 15 L/min and an experimental plot size of 1 m × 3 m. We found that runoff generation on shallow slopes was moderated by increasing vegetation cover, but that this moderating effect decreased on steeper slopes. The regime of overland flow switched from laminar and subcritical on the 5° slope (Fr = 0.56–0.87) to laminar and critical on the 10°, 15°, and 20° slopes (Fr = 1.02–2.18). Flow resistance increased with vegetation cover and flow rate and decreased with slope gradients, and it was larger on shallow slopes with high vegetation cover. Flow shear stress had a range of 1.42–3.55 N m−2, and it increased with increasing slope gradient, vegetation cover, and flow rate. The hydraulic characteristics of upslope runoff, especially flow resistance, were significantly related to vegetation pattern at both the landscape and class levels. Flow resistance was negatively related to patch density, and positively related to perimeter–area fractal dimension and connectance index. The influencing mechanism of landscape patterns on soil erosion processes is dependent on the landscape scale, since the relationships between flow resistance and some landscape pattern indices (aggregation index, effective mesh size, and splitting index) were opposite at the landscape level compared to the class level. We conclude that fragmented vegetation distributions reduce flow resistance, and that riparian vegetation could be managed to inhibit slope erosion by increasing flow resistance.

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Section: Effects Of Vegetation Cover and Slope Gradient On Runoff Hydsupporting

confidence: 90%

Relationships between Riparian Vegetation Pattern and the Hydraulic Characteristics of Upslope Runoff

Zhao

Zhang

et al. 2019

Sustainability

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“…where Vu i is the ratio of all the vegetation control area in the time zone i; ∆A Vcontrol,i is the total area of vegetation in time zone i (m 2 ); Veg is vegetation coverage (%); f (Veg) is function of Veg, it refers to runoff or sediment retention rate of the forestland or grassland with certain vegetation coverage, and f (Veg) is the average value of runoff or sediment retention rates in the time zone i. Most flume test researches in the Loess Plateau lack the complete information about the runoff and sediment retention rate of grassland and forestland with different cover [73][74][75][76]. Xiong et al [77] systematically deconstructed the experimental data from different slope runoff plots in the Loess Plateau, and summarized benefit indices of runoff and sediment reduction by forestland and grassland of different qualities in years with different runoff and sediment levels [77], as shown in Table 3.…”

Section: Consideration Of Vegetation Units In the Time-area Methodsmentioning

confidence: 99%

Assessing the Impact of Terraces and Vegetation on Runoff and Sediment Routing Using the Time-Area Method in the Chinese Loess Plateau

Bai

Yang

Zhang

et al. 2019

Water

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Terracing and vegetation are an effective practice for soil and water conservation on sloped terrain. They can significantly reduce the sediment yield from the surface area, as well as intercept the sediment yield from upstream. However, most hydrological models mainly simulate the effect of the terraces and vegetation on water and sediment reduction from themselves, without considering their roles in the routing process, and thus likely underestimate their runoff and sediment reduction effect. This study added the impact of terraces and vegetation practice on water and sediment routing using the time-area method. The outflow in each travel time zone was revised in each time step by extracting the watershed of the terrace units and the vegetation units and calculating the water or sediment stored by the terraces or held by the vegetation. The revised time-area method was integrated into the Land change Model-Modified Universal Soil Loss Equation (LCM-MUSLE) model. Pianguanhe Basin, in the Chinese Loess Plateau, was chosen as the study area and eight storms in the 1980s and 2010s were selected to calibrate and verify the original LCM-MUSLE model and its revised version. The results showed that the original model was not applicable in more recent years, since the surface was changed significantly as a result of revegetation and slope terracing, while the accuracy improved significantly when using the revised version. For the three events in the 2010s, the average runoff reduction rate in routing process was 51.02% for vegetation, 26.65% for terraces, and 71.86% for both terraces and vegetation. The average sediment reduction rate in routing process was 32.22% for vegetation, 24.52% for terraces, and 53.85% for both terraces and vegetation. This study provides a generalized method to quantitatively assess the impact of terraces and vegetation practice on runoff and sediment reduction at the catchment scale.

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Effect of Grass Coverage on the Sediment Concentration in Overland Flow in the Hillslope-Gully Side Erosion System

Cited by 2 publications

References 3 publications

Relationships between Riparian Vegetation Pattern and the Hydraulic Characteristics of Upslope Runoff

Relationships between Riparian Vegetation Pattern and the Hydraulic Characteristics of Upslope Runoff

Assessing the Impact of Terraces and Vegetation on Runoff and Sediment Routing Using the Time-Area Method in the Chinese Loess Plateau

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