The Effect of Rigid Vegetation on the Sediment Transport Rate on the Coast

Document Type : Research Paper

Authors

1 MSC Graduated, Department of Water Science Engineering, Shahrekord University, Shahrekord, Iran

2 Department of Water Science Engineering, Shahrekord University, Shahrekord, Iran

3 Department of Water Science Engineering, Shahrekord University, Shahrekord, Iran.

Abstract

Sedimen load is one of the important factors affecting the hydraulic performance and morphological structure of the beach. One of the solutions to reduce sediment transportation is vegetation as a bio system for sediment trapping. Vegetation due to flow obstruction and turbulence change, affects sediment transport. In this study, the effect of vegetation density on sediment transport rate along the shoreline was investigated. To consider this effect, beach and vegetation models were embedded in a knife edge flume equipped with a load cell and an Acoustic Doppler Velocimeter system (ADV). Experiments were performed in two triangular and rectangular layouts with a density of 12 to 273 stems per unit area. The results showed that by increasing the density of the vegetation and the number of tree rows, the sediment transfer rate decreases; So that in the highest density, the sediment transfer rate has increased up to 80% and in the lowest density this amount has reached 20%. Also, the triangular arrangement at the highest density was 25% and at the lowest density, it was 3% superior to the rectangular arrangement in reducing the sediment transfer rate. According to the variables studied in this investigation, density number changes have the greatest effect on sediment transfer rate, so that sediment transfer rate would decreases by increasing vegetation density. Through experimental formulas such as Kamphuis, Galvin, C.E.R.C and Van Der Meer, the obtained results were compared with the other studies.According to the statistical analyzes performed, the modified C.E.R.C formula would calculate the estimated sediment by a correlation coefficient of 92%.

Keywords

References

Battjes, J. A. (1974), Surf similarity, in ‘Proceedings of the 14-th Conference on Coastal Engineering’, number 1, pp. 466–480
 Chang HY and Hwung HH, (2006). Experimental on the run-up of solitary waves over sloping bottom. Symposium of Coastal and Ocean Engineering 1:14.
Chegini, W., (1998), Wave Theories, Jihad Water and Watershed Management Research Company Publications. First Edition. Tehran. Iran. 311 pages. . (in Farsi).
Chen, Y., C. E. L. Thompson, and M. B. Collins, (2012), Saltmarsh creek bank stability: Biostabilisation and consolidation with depth, Continental Shelf Research, 35, 64-74.
 Dean, R. G. and Dalrymple, R. A., (1991), Water Wave Mechanics for Engineers and Scientist, World Scientific Publishing, Singapore.
Ebrahimi. N. GH., Shirdeli. A., and Shafaei. H.,(2016), Sediment Trap and Flow Components in the Channel with Vegetation Cover. Journal of Applied Research in Irrigation and Drainage Structures Engineering/Vol.16/No.65/P:71-84.(in Farsi).
Emamizadeh, A. M., Zoljudi, M. and Lari, K.,(2017), Comparison of Estimation Rate and Volume of Sedimentation in Imam Khomeini Port Access Canal Using Hydrographic Methods, Biker Theory and Modeling by Mike 21. Scientific - Research Quarterly of Geographical Data (SEPEHR) Vo.27,No.106.(in Farsi).
Esteban, M. Thao, D. N. Takagi, H. and T, Shibayama, (2008), Analysis of rubble mound foundation failure of a caisson breakwater subjected to tsunami attack. 18th Offshore and Polar Engineering Conference, Vancouver, 7p.
Fu Li, J., Samkele S, T. and Su, C. C., (2018), Effects of Vegetation Density and Arrangement on Sediment Budget in a Sediment-Laden Flow, Journal Water, 10(10):1412.
Galvin, C.J. (1972). A cross longshore transport rate formula. Proceeding of the 13th Coastal Engineering Conference. Vancouver, B.C., Canada
Ghanbari Adivi, A. and Fathi Moghaddam, M.,(2014), Vegetation impact on the drag coefficient and resistance of trees against shore waves, Agricultural Journal of Irrigation Science and Engineering. Volume 38. Number 2 . Pages 103 -112(in Farsi).
 Ghanbari Adivi, E., Fathi Moghadam, M. and Sadri Nasab, M., 2015. Laboratory study at the impact of coastal green belt on wave attenuation. Journal of Marine Science and Technology, 13(4), pp.40-50 (in Farsi).
Gurnell, A., (2014), Plants as river system engineers, Earth Surf Process Landforms 39:4–25.
 Horppila, J.and Nurminen, L.,(2003), Effects of submerged macrophytes on sediment resuspension and internal phosphorus loading in lake hiidenvesi. Water Res, 37, 4468–4474.
Jalil Masir, H., Fattahi, R. And Ghanbari Adivi, A.,(2020), Impact of coastal forest cover on stabilization, protection and rehabilitation of sandy beaches exposed to tsunami waves. Khorramshahr Journal of Marine Science and Technology.(in Farsi).
Jalil Masir, H., Fattahi, R., Ghanbari-Adivi, E. and Aghbolaghi, M.A., 2021. Effects of different forest cover configurations on reducing the solitary wave-induced total sediment transport in coastal areas: An experimental study. Ocean Engineering, 235, p.109350
 Kamphuis, J.W. (1991). Alongshore Sediment Transport Rate. Journal of Waterway, Port, Coastal, and OceanEng. 117(6), pp. 624-640
Miche, R. (1954). Mouvement ondulatoires de la mer en profondeur constante ou decroissante, Annales des ponts et chausses.
Nardin, W., Larsen, L., Fagherazzi, S. and Wiberg, P., (2018), Tradeoffs among hydrodynamics, sediment fluxes and vegetation community in the Virginia Coast Reserve, USA. Estuarine, Coastal and Shelf Science 210: 98–108.
Parnak. F., Rahimpour. M. and Qaderi. K.,(2018), Experimental Investigation of the Effect of Rigid and Flexible Vegetation on Sediment Transport in Open Channels. Journal of Water and Soil Vol. 32, No. 2, May.-Jan. 2018, p. 239-252.(in Farsi).
Ratnosooriya, S. p. and N, Tanaka, (2008), Mitigation of tsunami by coastal vegetation. Journal of the Institute of Engineers, Sri Lanka, Annual Transactions of IESL, PP: 13- 19.
Sadeghifar T, Azarmsa S A, Vafakhah M. Prediction of Alongshore Sediment Transport Rate Using Semi-Empirical Formulas and an Artificial Neural Networks (ANNs) model in Noor Coastal zone . marine-engineering. 2013; 9 (17) :77-86
Sharpe, R. G. and James, C. S.,( 2006), Deposition of sediment from suspension in emergent vegetation.Water SA. 32(2): 211-218.
Shiono, K. L., Chan, T. L., Spooner, J., Rameshwaran. P. and Chandler, J. H.,(2009), The effect of floodplain roughness on flow structures, bedforms and sediment transport rates in meandering channels with overbank flows, Part II. J. Hydraul. Res. 47(1): 20-28.
Tuan Vu, M., Lacroix, Y. and Nguyen, V.T. Investigating the impacts of the regression of Posidonia oceanica on hydrodynamics and sediment transport in Giens Gulf. Ocean Engineering 146 -70–86.
Van der Meer, J.W. and Pilarczyk, K.W. (1990). Static and Dynamic Stabilityof Loose Materials. Coastal Protection. Balkema, Rotterdam. PP. 157-195
Vastila, K., Jarvela, J. and Koivusalo, H., (2016), Flow vegetation sediment interaction in a cohesive compound channel. Journal Hydraul Eng 142(1).
Wang, H., Tang, H.W., Zhao, H.Q., Zhao, X.Y. and Lü, S.Q., 2015. Incipient motion of sediment in presence of submerged flexible vegetation. Water Science and Engineering, 8(1), pp.63-67
Wang, H., Tang, H.W., Zhao, H.Q., Zhao, X.Y.and Lu, S.Q., (2015), Incipient motion of sediment in the presence of submerged flexible vegetation, Water Sci. Eng., 8, 63–67.
Zhang. Y., Laib. X., Zhanga. L.,Songc. K., Yaoa. X., Gub. L. and Pangd. C.,(2020). The influence of aquatic vegetation on flow structure and sediment deposition: A field study in Dongting Lake, China. Journal of Hydrology 584 . 124644.
Zhou. Z. C., Gan, Z. T. and Shangguan, Z. P.,(2013), Sediment trapping from hyperconcentrated flow as affected by grass filter strips. Pedosphere. 23(3): 372-375.
 
Iranian Journal of Soil and Water Research
Volume 52, Issue 8
November 2021
Pages 2155-2168

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