Determination of Emergent Vegetation Effects on Manning’s Coefficient of Gradually Varied Flow

Zhang, Huayong; Wang, Zhongyu; Xu, Weigang; Wang, Hualin

doi:10.1109/access.2019.2946917

Cited by 8 publications

(4 citation statements)

References 32 publications

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“…Where it raised upstream the vegetated reach then it lowered within it and gradually backed to the normal depth downstream the vegetated reach. This observation agreed with the previous studies [10][11][12][13][14][15]. From this result, it can say that sided vegetation acts as an obstacle to the flow, causing an increase in the flow resistance upstream it, thus the water depth increased.…”

Section: Results and Analysis 41 Effect Of Bank Vegetation On Water S...supporting

confidence: 92%

“…It concluded that for the same discharge, the vegetation density has a direct relationship with the water depth upstream of the vegetated reach. [14,15] experimentally studied the effect of rigid vegetation distributed in a channel's bed on water level and concluded that the water level rose upstream of the vegetation patch and then lowered through it. [15] Proposed a water surface slope equation in terms of vegetation density as follows;…”

Section: Introductionmentioning

confidence: 99%

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Heading Up and Head Losses Estimation Due to Rigid Bank Vegetation

Eraky¹,

El-Refaae²,

Abdelmoaty³

et al. 2023

Engineering Research Journal - Faculty of Engineering (Shoubra)

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Water surface profile is an important tool to design and manage hydraulic structures and watercourses flood control. However, limited studies focused on the effect of aquatic vegetation on the water depths in open channels. So the purpose of this paper is to investigate, how the density and distribution of the rigid bank vegetation affect the water depths in terms of heading up and head losses. Eighty-four tests were used, where tests were run for three vegetation densities (0.0113, 0.0028, and 0.0013) along 4.00 m fixed reach with varying Froude number. Water surface profiles were measured and plotted for all cases where it is observed that the water depth increased upstream the vegetated reach then lowered within it and gradually back to the normal depth downstream the vegetated reach. Empirical equations were deduced to determine the heading up and the head losses due to bank vegetation as a function in the vegetation density and the Froude number. The research presented empirical equations that assist in water management in vegetated open channels.

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Section: Results and Analysis 41 Effect Of Bank Vegetation On Water S...supporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Heading Up and Head Losses Estimation Due to Rigid Bank Vegetation

Eraky¹,

El-Refaae²,

Abdelmoaty³

et al. 2023

Engineering Research Journal - Faculty of Engineering (Shoubra)

View full text Add to dashboard Cite

show abstract

“…To study the transport of water in the drainage channels formed in the model according to the soil characteristics in the region of interest, different values of Manning Coefficient were adopted. The Manning Coefficient seeks to reflect the roughness of the channel and its interference with the water flow (ZHANG et al, 2019). The values used in this study were taken from Gribbin (2014) on pages 390, 391 and 392.…”

Section: Methodsmentioning

confidence: 99%

Study of the hydrological impact of the growth of a residential neighborhood on urban drainage – A case study at the city of Macaé, Rio de Janeiro, Brazil

Souza,

Lugon Junior

2023

CeN

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This paper aimed to study the drainage system of a residential neighborhood through a case study. Thus, a sensitivity analysis of drainage was carried out considering the progress of the urbanization process in the Imboassica district, in the municipality of Macaé, Rio de Janeiro. It was possible to evaluate the model’s response to different land use planning, represented with variations in the Manning coefficient and also in the Curve Number. The MOHID platform was used along with the OpenFlows FLOOD® software interface to elaborate scenarios with different soil characteristics, and distinct Digital Elevation Model (DEM) were adopted. In the first evaluation, three simulations (1, 2 and 3) were performed considering the natural topography of the terrain, using altimetry data obtained from the TOPODATA project of the National Institute for Space Research (INPE). Afterwards, the elevation quota represented in the Digital Elevation Model (DEM) was raised by 10 meters in the locations corresponding to the location of the houses and by 1 meter in the roads of the residential condominium, and then the three simulations (4, 5, and 6) were performed. The six simulations adopted the 10 years return period Rain Design. After that, another set of six simulations were performed, adopting the 50 years return period Rain Design. It was possible to observe that in the simulations considering the change in the elevations due to the presence to the houses and the road, the calculated value of the water depth increases in the drainage channels. The effect of the Curve Number changes was observed in the flood peak simulation, which is reduced due to the presence to greater vegetation. And finally, it was possible to observe the effect of the change in the Manning’s Coefficient, whose increase caused a delay in runoff.

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“…It is also worth pointing out that some authors, in case of channels with emergent rigid vegetation, have directly focused on the Manning or Darcy-Weisbach coefficient instead of considering the dependence of the resistance to flow on C D [48][49][50].…”

Section: Overview and Basic Definitionmentioning

confidence: 99%

Simulation of Accelerated Subcritical Flow Profiles in an Open Channel with Emergent Rigid Vegetation

et al. 2022

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Even though both fluid mechanics and numerical studies have considerably progressed in the past decades, experimental knowledge remains an important tool for studying the resistance to flow in fluid media where a complex environment dominates the flow pattern. After a comprehensive review of the recent literature on the drag coefficient in open channels with emergent rigid vegetation, this paper presents the results related to 29 experimental accelerated subcritical flow profiles (i.e., M2 type) that were observed in flume experiments with emergent stems in a square arrangement at the University of Calabria (Italy). First of all, we used some of the literature formulas for the drag coefficient, concluding that they were unsatisfactory, probably because of their derivation for uniform or quasi-uniform flow conditions. Then, we tested a recently proposed approach, but when we plotted the drag coefficient versus the stem Reynolds number, the calculated drag coefficients showed an inconclusive behavior to interpret. Thus, we proposed a new approach that considers the calibration of the Manning coefficient for the simulation of the free surface profile, and then the evaluation of the drag coefficients based on the fundamental fluid mechanics equations. With the help of classical dimensional analysis, a regression equation was found to estimate the drag coefficients by means of non-dimensional parameters, which include vegetation density, stem Reynolds number and flow Reynolds number computed using the flow depth as characteristic length. This equation was used to simulate all the 26 observed profiles and, also, 4 experimental literature profiles, and the results were good. The regression equation could be used to estimate the drag coefficient for the M2 profiles in channels with squared stem arrangements, within the range of vegetation densities, flow Reynolds numbers and stem Reynolds numbers of the present study. However, in the case of the three profiles observed by the authors for staggered arrangement, the regression equation gives significantly underestimated flow depths.

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Determination of Emergent Vegetation Effects on Manning’s Coefficient of Gradually Varied Flow

Cited by 8 publications

References 32 publications

Heading Up and Head Losses Estimation Due to Rigid Bank Vegetation

Heading Up and Head Losses Estimation Due to Rigid Bank Vegetation

Study of the hydrological impact of the growth of a residential neighborhood on urban drainage – A case study at the city of Macaé, Rio de Janeiro, Brazil

Simulation of Accelerated Subcritical Flow Profiles in an Open Channel with Emergent Rigid Vegetation

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