# Influence of Floodplain Flooding on Channel Siltation Adjustment under the Effect of Vegetation on a Meandering Riverine Beach

^{1}

^{2}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

#### 2.1. Test Setup

#### 2.1.1. Model Design

#### 2.1.2. Measuring Equipment

#### 2.1.3. Vegetation Arrangement

#### 2.1.4. Layout of Measuring Points

#### 2.1.5. Test Conditions

^{3}/h, and the actual situation was a little different.

^{3}for small sediment concentration, 14.5 kg/m

^{3}for medium sediment concentration, and 35.3 kg/m

^{3}for large sediment concentration (Table 1). The test tailgate could automatically adjust the height and control the water level of the tailgate. The Reynolds number in CS24 near downstream tailgate is about 5388, and the Froude is about 0.051. The numbers in other sections are greater than these numbers.

#### 2.2. Effect of Bend on Transverse Distribution of Floodplain Flow

#### 2.2.1. Governing Equation of Water Flow

_{d}is the vertical average velocity in the downstream direction; ρ is the fluid density; g is the acceleration of gravity; H is the water depth; S

_{0}is the bed slope in the downstream direction; f is the bed friction factor; r is the available curvature of bed slope in the main channel and riverine beach; y is the transverse coordinate; Γ is the quadratic flow term; γ is the exponent of the analytical solution of the differential equation; and A is the unknown constant.

#### 2.2.2. Boundary Conditions

_{1}, A

_{2}, A

_{3}, and A

_{4}can be obtained by solving this linear equation system. The transverse distribution of the average velocity of the vertical line of the meandering compound rectangular compound channel was obtained.

## 3. Results and Discussions

#### 3.1. Characteristics of the Water and Sediment Transport of a Flood under the Effect of Vegetation in a Bend Floodplain

#### 3.2. Effect of the Bend Curvature on the Transverse Distribution of the Flow and Sediment Factors in Compound Channels

#### 3.3. Effect of Floodplain Flooding on the Channel Filtation Adjustment under the Effect of Riverine Beach Vegetation

## 4. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

- Tang, X.N.; Knight, D.W. Lateral distributions of streamwise velocity in compound channels with partially vegetated floodplains. Sci. China Ser. E
**2009**, 52, 3357–3362. [Google Scholar] [CrossRef] - Tang, X.N.; Knight, D.W. Lateral depth-averaged velocity distributions and bed shear in rectangular compound channels. J. Hydraul. Eng.
**2008**, 134, 1337–1342. [Google Scholar] [CrossRef] - Fischer-Antze, T.; Stoesser, T.; Bates, P.; Olsen, N.R.B. 3D numerical modelling of open-channel flow with submerged vegetation. J. Hydraul. Res.
**2001**, 39, 303–310. [Google Scholar] [CrossRef] - Yang, K.; Cao, S.; Knight, D.W. Flow patterns in compound channels with vegetated flood plains. J. Hydraul. Eng.
**2007**, 133, 148–159. [Google Scholar] [CrossRef] - Mehrabani, F.V.; Mohammadi, M.; Ayyoubzadeh, S.A.; Fernandes, J.N.; Rui, M.L.F. Turbulent flow structure in a vegetated non-prismatic compound channel. River Res. Appl.
**2020**, 36, 1868–1878. [Google Scholar] [CrossRef] - Pan, Y.; Li, Z.; Yang, K.; Jia, D. Velocity distribution characteristics in meandering compound channels with one-sided vegetated floodplains. J. Hydrol.
**2019**, 578, 124068. [Google Scholar] [CrossRef] - Fernandes, J.N.; Leal, J.B.; Cardoso, A.H.; Paquier, A.; Rivière, N. Influence of floodplain and riparian vegetation in the conveyance and structure of turbulent flow in compound channels. E3S Web Conf.
**2018**, 40, 06035. [Google Scholar] [CrossRef] - Proust, S.; Peltier, Y.; Fernandes, J.; Leal, J.; Rivière, N. Effect of different inlet flow conditions on turbulence in a straight compound open channel. In Proceedings of the 34th World Congress of the International Association for Hydro-Environment Research and Engineering: 33rd Hydrology and Water Resources Symposium and 10th Conference on Hydraulics in Water Engineering, Brisbane, Australia, 26 June–1 July 2011. [Google Scholar]
- Tanino, Y.; Nepf, H.M. Laboratory investigation of mean drag in a random array of rigid, emergent cylinders. J. Hydraul. Eng.
**2008**, 134, 34–41. [Google Scholar] [CrossRef] - Shiono, K.; Feng, T. Turbulence measurements of dye concentration and effects of secondary flow on distribution in open channel flows. J. Hydraul. Eng.
**2003**, 129, 373–384. [Google Scholar] [CrossRef] - Sun, X.; Shiono, K. Flow resistance of one-line emergent vegetation along the floodplain edge of a compound open channel. Adv. Water Res.
**2009**, 32, 430–438. [Google Scholar] [CrossRef] - Hu, C.; Ji, Z.; Guo, Q. Flow movement and sediment transport in compound channels. J. Hydraul. Res.
**2010**, 48, 23–32. [Google Scholar] [CrossRef][Green Version] - Shiono, K.; Knight, D.W. Turbulent open channel flows with variable depth across the channel. J. Fluid Mech.
**1991**, 222, 617–646. [Google Scholar] [CrossRef] - Naot, D.; Nezu, I.; Nakagawa, H. Hydrodynamic behavior of partly vegetated open channels. J. Hydraul. Eng.
**1996**, 122, 625–633. [Google Scholar] [CrossRef] - Ervine, D.A.; Babaeyan-Koopaei, K.; Sellin, R.H.J. Two-dimensional solution for straight and meandering overbank flows. J. Hydraul. Eng.
**2000**, 126, 653–669. [Google Scholar] [CrossRef] - Wormleaton, P.R.; Hadjipanos, P. Flow distribution in compound channels. J. Hydraul. Eng.
**1985**, 111, 357–361. [Google Scholar] [CrossRef] - Yang, S.Q.; Tan, S.K.; Lim, S.Y. Velocity distribution and dip-phenomenon in smooth uniform open channel flows. J. Hydraul. Eng.
**2004**, 130, 1179–1186. [Google Scholar] [CrossRef] - Rameshwaran, P.; Shiono, K. Quasi two-dimensional model for straight overbank flows through emergent vegetation on floodplains. J. Hydraul. Res.
**2007**, 45, 302–315. [Google Scholar] [CrossRef] - Velasco, D.; Bateman, A.; Medina, V. A new integrated, hydro-mechanical model applied to flexible vegetation in riverbeds. J. Hydraul. Res.
**2008**, 46, 579–597. [Google Scholar] [CrossRef] - Brito, M.; Fernandes, J.; Leal, J.B. Porous media approach for RANS simulation of compound open-channel flows with submerged vegetated floodplains. Environ. Fluid. Mech.
**2016**, 16, 1247–1266. [Google Scholar] [CrossRef][Green Version] - Rameshwaran, P.; Willetts, B.B. Conveyance prediction for meandering two-stage channel flows. Proc. Inst. Civil Eng. Water
**1999**, 136, 153–166. [Google Scholar] [CrossRef] - Ervine, D.A.; Macleod, A.B. Modelling a river channel with distant floodbanks. Proc. Inst. Civil Eng.-Water
**1999**, 136, 21–33. [Google Scholar] [CrossRef] - Huthoff, F.; Augustijn, D.C.M.; Hulscher, S. Analytical solution of the depth-averaged flow velocity in case of submerged rigid cylindrical vegetation. Water Resour. Res.
**2007**, 43, W06413. [Google Scholar] [CrossRef][Green Version] - Liao, H.; Knight, D.W. Analytic stage-discharge formulas for flow in straight prismatic channels. J. Hydraul. Eng.
**2007**, 133, 1111–1122. [Google Scholar] [CrossRef] - Liao, H.; Knight, D.W. Analytic stage-discharge formulae for flow in straight trapezoidal open channels. Adv. Water Res.
**2007**, 30, 2283–2295. [Google Scholar] [CrossRef] - Knight, D.W. Flow mechanisms and sediment transport in compound channels. Int. J. Sediment Res.
**1999**, 14, 217–236. [Google Scholar] - Wu, F.C.; Shen, H.W.; Chou, Y.J. Variation of roughness coefficients for unsubmerged and submerged vegetation. J. Hydraul. Eng.
**1999**, 125, 934–942. [Google Scholar] [CrossRef][Green Version] - Stone, B.M.; Hung, T.S. Hydraulic resistance of flow in channels with cylindrical roughness. J. Hydraul. Eng.
**2002**, 128, 500–506. [Google Scholar] [CrossRef] - Shiono, K.; Knight, D.W. Mathematical models of flow in two or multi stage straight channels. In Proceedings of the International Conference on River Flood Hydraulics, Wallingford, UK, 17–20 September 1990; John Wiley & Sons: New York, NY, USA, 1990; pp. 229–238. [Google Scholar]
- Liu, C.; Wright, N.; Liu, X.; Yang, K. An analytical model for lateral depth-averaged velocity distributions along a meander in curved compound channels. Adv. Water Resour.
**2014**, 74, 26–43. [Google Scholar] [CrossRef] - Shan, Y.; Liu, C.; Luo, M. Simple analytical model for depth-averaged velocity in meandering compound channels. Adv. Appl. Math. Mech.
**2015**, 36, 707–718. [Google Scholar] [CrossRef] - Zhang, H.W.; Jiang, E.H.; Zhao, X.J.; Zhang, Q. Model similarity conditions of hyper-concentrated flood of the Yellow River. Yellow River
**1994**, 4, 1–3. [Google Scholar] - Quesada-Roán, A.; Ballesteros-Cánovas, J.A.; Granados-Bolaños, S.; Birkel, C.; Stoffel, M. Dendrogeomorphic reconstruction of floods in a dynamic tropical river. Geomorphology
**2020**, 359, 107133. [Google Scholar] [CrossRef] - Quesada-Román, A.; Villalobos-Chacón, A. Flash flood impacts of Hurricane Otto and hydrometeorological risk mapping in Costa Rica. Geogr. Tidsskr. Dan. J. Geogr.
**2020**, 120, 142–155. [Google Scholar] [CrossRef] - Huai, W.X.; Zeng, Y.H.; Xu, Z.G.; Yang, Z.H. Three-layer model for vertical velocity distribution in open channel flow with submerged rigid vegetation. Adv. Water Res.
**2009**, 32, 487–492. [Google Scholar] [CrossRef]

**Figure 3.**Schematic diagram of the meandering arc top section of a meandering compound rectangular channel.

**Figure 4.**Comparison of the velocity and topography of meandering compound channel sections under different working conditions (The blue line is the terrain at the end of all working conditions).

**Figure 5.**Transverse distribution of the top flow, sediment carrying capacity, and velocity in a meandering compound rectangular channel. (

**A**), effect of the bend curvature on the transverse distribution of the flow; (

**B**) effect of the bend curvature on the transverse distribution of the sediment carrying capacity.

**Figure 6.**Topographic changes of each section: CS1–CS5, front riverine beach without vegetation and a straight compound channel section; CS6–CS9, with no vegetation and a meandering compound channel area on the riverine beach; CS10–CS13, the convex bank of the riverine beach with vegetation and a meandering compound channel area; CS14–CS17, the riverine beach concave bank with vegetation and a meandering compound channel area; CS18–21, with vegetation and a meandering compound channel area on both sides of the riverine beach; CS22–CS25, the flat land covered with vegetation and meandering compound channel areas; CS26–CS29, after the riverine beach without vegetation and a straight compound channel area.

Working Condition | Design Flow (m^{3}/h) | Actual Flow | Design Sediment Concentration | Actual Sediment Concentration (kg/m^{3}) | Design Particle Size |
---|---|---|---|---|---|

0 | 100 | 100.2 | no | 0 | no |

1 | 100 | 90.7 | no | 0 | no |

2 | 100 | 93.1 | small | 5.23 | fine |

3 | 100 | 101.3 | large | 35.37 | fine |

4 | 100 | 104.8 | middle | 14.39 | fine |

5 | 100 | 100.6 | small | 4.84 | coarse |

6 | 100 | 101.5 | middle | 14.85 | coarse |

7 | 100 | 101.5 | large | 35.30 | coarse |

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Li, J.; Zhang, M.; Jiang, E.; Pan, L.; Wang, A.; Wang, Y.; Jian, S. Influence of Floodplain Flooding on Channel Siltation Adjustment under the Effect of Vegetation on a Meandering Riverine Beach. *Water* **2021**, *13*, 1402.
https://doi.org/10.3390/w13101402

**AMA Style**

Li J, Zhang M, Jiang E, Pan L, Wang A, Wang Y, Jian S. Influence of Floodplain Flooding on Channel Siltation Adjustment under the Effect of Vegetation on a Meandering Riverine Beach. *Water*. 2021; 13(10):1402.
https://doi.org/10.3390/w13101402

**Chicago/Turabian Style**

Li, Junhua, Mingwu Zhang, Enhui Jiang, Li Pan, Aoxue Wang, Yafei Wang, and Shengqi Jian. 2021. "Influence of Floodplain Flooding on Channel Siltation Adjustment under the Effect of Vegetation on a Meandering Riverine Beach" *Water* 13, no. 10: 1402.
https://doi.org/10.3390/w13101402