Effects of simulated submerged and rigid vegetation and grain roughness on hydraulic resistance to simulated overland flow

Yang, Pingping; Zhang, Huilan; Ma, Chao

doi:10.1007/s11629-016-4280-0

Cited by 12 publications

(11 citation statements)

References 38 publications

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“…Vegetation type, coverage and slope gradient have also important effects on the overland flow resistance. Previous studies have shown that the relationship between f total and Re can be either positive or negative (Abrahams et al, 1994;Al-Hamdan et al, 2012;Yang et al, 2017;Ye et al, 2015). The reason for this difference may be caused by different experimental designs.…”

Section: Effect Of Vegetation Density On F Total -Re Relationshipsmentioning

confidence: 99%

“…The f–Re relation is also affected by vegetation cover. Yang et al (2017) obtained a positive correlation between f and Re on vegetation‐covered slope. Furthermore, Zhang et al (2017) found that the relationship between f and Re was not constant, and there was a critical coverage that made them appear differently correlated.…”

Section: Introductionmentioning

confidence: 96%

“…Although the component of flow resistance is clearly divided by the linear superposition approach, other studies have questioned the universality of this approach (Li, 2009; Yang et al, 2017). Li (2009) found the flow resistance was significantly affected by rainfall, and the comprehensive resistance was not equal to the sum of single resistance elements.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study on the effect of simulated grass and stem coverage on resistance coefficient of overland flow

Cen

Zhang

Peng

et al. 2022

Hydrological Processes

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Vegetation plays a significant role in preventing desertification, conservation of soil and water. However, nowadays, there is still uncertainty regarding the mechanisms of flow resistance caused by dissimilar vegetation covers. To address this gap, a series of these was conducted in this study to investigate the influence of synthetic grass and stems on the variation of resistance on overland flows. Thirty vegetation configurations were selected (combining five synthetic grass coverage options and six synthetic stem coverage ones), and tested against five unit discharges (flow range = 0.28–2.22 L m−1 s−1) and four slope gradients (3.49%–20.78%). The results obtained showed that the unit discharge is the key driving factor for the transition from laminar to transitional flow. Furthermore, the relationship between the resistance coefficient (f) and the Reynolds number (Re) was not monotonically increasing or decreasing, but behaviours observed were specifically linked to each vegetation coverage. However, a critical coverage threshold was identified, and it corresponded to 2.72% when the slope gradient tested was 3.49%. This threshold decreased with the increase of the slope gradient. In addition, when the vegetation coverage was less than the critical threshold, the f was negatively correlated with Re, otherwise if the vegetation coverage was higher than the critical threshold identified the f–Re relation was positively correlated. The total flow resistance under synthetic grass and stem cover was unequal to the linear superposition of grain resistance and form resistance caused by synthetic stem and grass, which meant that the linear superposition approach is not applicable to overland flows. Finally, a model was developed to predict the flow resistance by applying the π‐theorem and the multiple nonlinear regression analysis and it has been validated against the experimental results confirming its accuracy and high performance (adj.R2 = 0.99, NSE = 0.94).

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Section: Effect Of Vegetation Density On F Total -Re Relationshipsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Experimental study on the effect of simulated grass and stem coverage on resistance coefficient of overland flow

Cen

Zhang

Peng

et al. 2022

Hydrological Processes

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“…The essence of the division of flow resistance is to combine and classify the source of flow resistance according to the source of turbulence (Yang et al 2017). It is g e n e r a l l y c o n s i d e r e d t h a t t h e f l o w r e s i s t a n c e Cr=0.07%…”

Section: Reynolds Number Rementioning

confidence: 99%

Effects of sparse rigid stem vegetation coverage on hydrodynamic characteristics of overland flow in a gentle slope area

Zhang

Chen

et al. 2021

Arab J Geosci

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Vegetation plays a vital role in natural ecosystems, especially in soil and water conservation. The accurate estimation of hydraulic parameters of overland flow is an important means to understand the hydraulic characteristics of overland flow and soil erosion. However, there is limited research on sparse stem vegetation coverage under gentle slope conditions. This study aims to understand the inherent laws that control overland flow structure under sparse vegetation cover. To achieve this, hydraulic characteristics of surface runoff on slopes covered by stem vegetation were quantified for seven flow discharges (Q) (0.0313-0.5203 m 3 /min), four slopes (S) (0.0-3.0%), and six stem coverage degrees (Cr) (0.07-0.72%) through a laboratory flume. The results showed that the same impact factor has different degrees of influence on different hydraulic parameters of overland flow resulting in varied hydrodynamic characteristics. In this study, for the vegetation coverage of sparse stems, under the condition of the flat slope, Cr is the dominant factor affecting Froude number and Manning roughness coefficient, whereas Q is the dominant factor affecting flow velocity and Reynolds number. However, under the condition of the non-flat slope, Cr is the dominant factor affecting Manning roughness coefficient, Q is the dominant factor affecting Reynolds number, and S is the dominant factor affecting the velocity and Froude number.

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“…Flow conditions at various plant configurations were also investigated among others by [6][7][8][9][10]. Yang et al [11] studied the hydraulic characteristics of overland flow. The results show that overland flow velocity remains constant at about 10% for vegetation stems.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Shrubby Floodplain Vegetation Growth on the Discharge Capacity of River Valleys

Walczak

Kałuża

et al. 2018

Water

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Willow bush growing in floodplains is a dominant form of vegetation in lowland river valleys due to the availability of water and light. Uncontrolled growth of this plant results in a lower capacity of floodplain areas. Vegetation can narrow the active width of water flow, as well as change water flow velocities at hydrometric verticals falling within the floodplain and the main channel. This paper analyses the impact of long-term growth of willow shrubs on flow resistance coefficient values. Both an increase in the average diameter and the density characterised by the average distance between branches have a significant impact on reducing the flow. The adopted research variants were based on data on the growth rate of the most popular species and forms of willow found in the floodplains of the Warta River above the Jeziorsko reservoir. Two research scenarios were analysed, including data from 12 years, on the development of floodplain vegetation. The first scenario included only the change in diameter (vegetation grew on a cultivation plot), whereas the density remained constant. The second scenario investigated the inverse model-vegetation growing in an uncontrolled manner. The analysis of the tests proved the impact of various bush development scenarios on flow conditions. The results, referred to in the available research papers, indicated the importance of the dynamics of shrub development to the local flow conditions. It was stated that reduction in the flow, depending on the analysed scenario, could reach 45% for scenarios in which the only considered factor was the increase in diameter (at a constant density), and up to 70% in the case of increase in the density of vegetation. Thorough knowledge of this phenomenon may help manage and maintain natural river valleys.

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Effects of simulated submerged and rigid vegetation and grain roughness on hydraulic resistance to simulated overland flow

Cited by 12 publications

References 38 publications

Experimental study on the effect of simulated grass and stem coverage on resistance coefficient of overland flow

Experimental study on the effect of simulated grass and stem coverage on resistance coefficient of overland flow

Effects of sparse rigid stem vegetation coverage on hydrodynamic characteristics of overland flow in a gentle slope area

The Impact of Shrubby Floodplain Vegetation Growth on the Discharge Capacity of River Valleys

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