Modeling the Effects of Coastal Vegetation in Mitigating Tsunami and Flood Current

Abstract:

In order to protect coastal regions effective natural strategies are needed because of increasing intensity and frequency of tsunami and flood events. This study aims to explore the role of coastal vegetation for mitigating the tsunami and flood induced currents. To simulate interaction between tsunami waves and coastal vegetation, a detailed model is developed with the help of ANSYS FLUENT by using Computational Fluid Dynamics (CFD) techniques in this study. Critical flow characteristic such as velocity is the focus of simulations. To see that how the tree structure effects the reduction of tsunami and flood currents, the model incorporated different configurations of coastal vegetation (Linear and Staggered Arrangement). In case of linear arrangement, the highest increased value of velocity has found to be 32% of inlet velocity. On the other hand, in case of staggered arrangement the highest increased value of velocity has found to be 39.6% of inlet velocity.

• Periodical: Construction Technologies and Architecture (Volume 17)
• Pages: 181-189
• DOI: https://doi.org/10.4028/p-Djs0RZ
• Online since: April 2025
• Authors: Syed Muhammad Ahmad*, Naveed Anjum, Muhammad Saad Abbas, Adnan Shahid, Abdul Basit Bukhari, Ahmed Sohail, Zaheer Ahmad, Hanzala Aslam
• Keywords: Coastal Forest, Computational Fluid Dynamics (CFD), Numerical Investigation, Tsunami Mitigation

References

[1] Udo, K., Sugawara, D., Tanaka, H., Imai, K., Mano, A., 2012. Impact of the 2011 Tohoku earthquake and tsunami on beach morphology along the northern Sendai coast. Coast Eng. J. 54 (1), 1250009–1250015.

DOI: 10.1142/s057856341250009x

[2] Suppasri A, Koshimura S, Imai K, Mas E, Gokon H, Muhari A, Imamura F (2012) Damage characteristic and feld survey of the 2011 Great East Japan tsunami in Miyagi prefecture. Coast Eng J 54(1):1250005-1-1250005–30

DOI: 10.1142/s0578563412500052

[3] Tanaka N, Yagisawa J, Yasuda S (2013) Breaking pattern and critical breaking condition of Japanese pine trees on coastal sand dunes in huge tsunami caused by Great East Japan Earthquake. Nat Hazards 65:423–442

DOI: 10.1007/s11069-012-0373-4

[4] Harada, K., Imamura, F., 2000. Experimental Study on the Resistance by Mangrove under the Unsteady Flow. In: Proceedings of the 1st Congress of the Asian and Pacific Coastal Engineering. Dalian, China, p.975–984.

[5] Hiraishi, T., Harada, K., 2003. Greenbelt tsunami prevention in South- Pacific region. Rep. Port. Airpt. Res. Inst. 42 (2), 23.

[6] Shuto N (1987) The effectiveness and limit of Tsunami control forests. Coast Eng Jpn 30(1): 143153

[7] Yanagisawa H, Koshimura S, Miyagi T, Imamura F (2010) Tsunami damage reduction performance of a mangrove forest in Banda aceh, Indonesia inferred from field data and a numerical model. J Geophys Res 115:C06032

DOI: 10.1029/2009jc005587

[8] Tanaka N (2009) Vegetation bioshields for Tsunami mitigation: review of the effectiveness, limitations, construction and sustainable management. Lands Ecol Eng 5:71-79

DOI: 10.1007/s11355-008-0058-z

[9] Alongi, D. M. (2008). Mangrove forests: Resilience, protection from tsunamis, and responses to global climate change. Estuarine, Coastal and Shelf Science, 76(1), 1-13

DOI: 10.1016/j.ecss.2007.08.024

[10] Anjum, N., Tanaka, N. Experimental study on flow analysis and energy loss around discontinued vertically layered vegetation. Environ Fluid Mech 20, 791–817 (2020)

DOI: 10.1007/s10652-019-09723-8

[11] Danielsen, F., Sørensen, M. K., Olwig, M. F., Selvam, V., Parish, F., Burgess, N. D., ... & Quarto, A. (2005). The Asian tsunami: A protective role for coastal vegetation. Science, 310(5748), 643.

DOI: 10.1126/science.1118387

[12] Maza, M., Lara, J. L., Losada, I. J., & Ondiviela, B. (2015). Role of vegetation density on wave attenuation: A laboratory study with synthetic canopies. Coastal Engineering, 98, 1-16.

[13] Pasha, G.A., Tanaka, N., 2017. Undular hydraulic jump formation and energy loss in a flow through emergent vegetation of varying thickness and density. Ocean. Eng. 141, 308–325.

DOI: 10.1016/j.oceaneng.2017.06.049

[14] Takemura, T., Tanaka, N., 2007. Flow structures and drag characteristics of a colony-type emergent roughness model mounted on a flat plate in uniform flow. Fluid Dynam. Res. 39, 694–710.

DOI: 10.1016/j.fluiddyn.2007.06.001

[15] Mazda, Y., Magi, M., Kogo, M., & Hong, P. N. (2006). Wave reduction in mangrove forests. Journal of Oceanography, 62(4), 517-528