Effect of coastal vegetation on attenuation of non-breaking solitary wave force in sloping coast lines

Document Type : Original Article

Authors

1 Professor of faculty of Water Science Engineering of Ahvaz Chamran University

2 P.h.D Student, Faculty of Water Science Engineering, Shahid Chamran University of Ahwaz

Abstract

Wave attack is the main source of irreparable damages to the sea coast line. The coastal protection techniques are now improved from structural protection to biological ones. This includes plantation of trees and development of vegetation canopy (called green belt) along the shorelines and protection of coastal structures against the waves created by tsunami. For this, the application of green belt has been studied and effect of vegetation density and wave height on wave force is evaluated for waves in broken condition. Experiments were conducted in a flume with 8.3m length, 0.8m width, and 0.55m height. Experimental variables include four bed slopes, four vegetation densities, and 110 wave heights. The results show that absorption of wave force increase with increase of wave height and density of vegetation. At the highest vegetation density the wave force effect was reduced by about 75% compared to the case without vegetation

Keywords


      حیدرزاده، م.، م. دولتشاهی، ن. حاجی زاده ذاکر و م. مختاری. ۱۳۸۶. بررسی خطر سونامی در سواحل جنوبی ایران در حاشیه اقیانوس هند، سومین کنگره ملی مهندسی عمران، تبریز، دانشگاه تبریز، دانشکده فنی - مهندسی عمران
     لشکرآرا، ب.، 1388. تعیین تنش برشی در کانال­های مستطیلی با استفاده از روش­های ممنتم و انرژی، رساله دکتری، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز.
     لشکرآرا، ب. و م. فتحی­مقدم. 1393. تحلیل تنش برشی در کانال­های روباز با مقطع مستطیلی به روش تعادل نیرو، نشریه هیدرولیک، 9(3): 44-33.
راست­گفتار، ا.، م. اکبرپور جنت، و. چگینی و م. رستمی. 1391. بررسی آب­گرفتگی خلیج چابهار در اثر سونامی ناحیه­ی فرورو مکران، دهمین همایش بین­المللی سواحل، بنادر و سازه­های دریایی، تهران، 29 آبان ماه.
Cavallaro, L., C. L. Re, G. Paratore, A. Viviano, and E. Foti.2010. Response of Posidonia oceanic to wave motion in shallow waters: Preliminary experimental results. Proceedings of the 32nd
Chatenoux, B. and P. Peduzzi. 2005. Analysis of the role of bathymetry and other environmental parameters in the impacts from the 2004 Indian Ocean Tsunami, UNEP/GRID-Europe, 25 pp.
Dahdouh-Guebas, F., L. P. Jayatissa, D. Di Nitto, J. O. Bosire, D. Lo Seen, and N. Koedam. 2005. How effective were mangroves as a defense against the recent tsunami, Cur .biol. 15(12), 443–447,
Dean, R. G., and R. A. Dalrymple. 1991. Water Wave Mechanics for Engineers and Scientist. World Scientific Publishing. Singapore.
Esteban, M., D. Nguyen. 2008. Analysis of rubble mound foundation failure of a caisson breakwater subjected to tsunami attack. 18th Int Offshore and Polar Engineering Conference, Vancouver.
Evangelista, S., M. S., Altinakar, C., Di Cristo, and A.Leopardi. 2013. Simulation of dam break on movable beds using a multi-stage centered scheme. International Journal of Sediment Research, 28, 269–284.
Fathi-Moghadam., M. 1997. Momentum absorption in non- rigid, non- submerged, tall vegetation along rivers. University of Waterloo, Canada, PhD. Thesis
Geist, E. L., V. V. Titov, and C. E. Synolakis.2006. "Tsunami: wave of change." Scientific American, January2006, PP. 56-63.
Hirashi, T. and K. Harada. 2003. Green belt tsunami prevention in South- Pacific region. Report of the Port and Airport Research Institute. 42(2): 23p
Husrin, S. and H. Oumeraci. 2009. Parameterization of coastal forest vegetation and hydraulic resistance coefficients for tsunami modelling, Proceedings of the 4th Annual
International Workshop and Expo on Sumatra Tsunami Disaster and Recovery, Banda Aceh, Indonesia, 78–86.
 
Husrin, S., A. Strusinska, and H. Oumeraci. 2012. Experimental study on tsunami attenuation by mangrove forest. Earth Planets Space Journal. 64: 973- 989.
Imai, K. and H. Matsutomi. 2005. Fluid force on vegetation due to the tsunami flow on sand spit, in Tsunamis: Case Studies and Recent Developments, edited by K. Satake, 343 pp, Springer, The Netherlands.
Istiyanto, D. C., K. S. Utomo, and Suranto, Pengaruh Rumpun Bakau Terhadap Perambatan Tsunami di Pantai. 2003, Proceeding of Reducing the Impact of Tsunami Seminar, BPPT JICA, Yogyakarta, Indonesia, 316–326.
Mascarenhas, A., S.Jayakumar, 2008. An environmental perspective of the post tsunami scenario along the coast of Tamil Nadu, India: Role of sand dunes and forests. J. Env. Management 89(1), 24-34.
Méndez, F.J. and I.J. Losada. 2004. An empirical model to estimate the propagation of random breaking and nonbreaking waves over vegetation fields. Coastal Engineering. 51(2): 103-118.
Nakagawa, H., S., Nakamura, and K. Ichihashi. 1969. Generation of a hydraulic bore due to the breaking of a dam (1).Bulletin of the Disaster Prevention Research Institute, 19(2),–17.
Namdar, A., A. Nusrath. 2010. Tsunami numerical modeling and mitigation. Journal of Frattura  Integrità Strutturale 12, 57-62.
Nepf, H.M. 1999. Drag, turbulence, and diffusion in flow through emergent vegetation. Water Resources Research. 35(2): 479-489.
Nioklas, K. J., 1992, “PLANT BIOMECHANICS: An Engineering Approach to Plant Form and Function”, The University of Chicago Press, Chicago & London, 607p.
Ratnasooriya, S. P., S. S. L, Samarawichrama, Hettiarachchi, Banadara, R. P. S. S. and N. Tanaka. 2008. Mitigation of tsunami by coastal vegetation. Journal of the Institution of Engineers, Sri Lanka, 13-19.
Satake, K. and Y, Tanioka. 1999. Source of Tsunami and Tsunami genic earthquakes in subduction zones.Pure and Applied Geophysics, Vol. 154, PP. 467-483.
Soares-Frazao, S., and Y. Zech. 2002. Undular bores and secondary waves – experiments and hybrid finite-volume modelling. Journal of Hydraulic Research, 40(1), 33–43.
Sorensen, R.M. 2006. Basic Coastal Engineering. Springer Science. New York.
Watts P. 2004. Probabilistic predictions of landslide tsunamis off Southern California; Marine Geology. Vol. 203, Pages 281-301.
Yamamoto, Y., H., Takanashi, S., Hettiarachchi, and S. Samarawickrama, 2006. Verification of the destruction mechanism of structures in Sri Lanka and Thailand due to the Indian Ocean tsunami. Coastal Eng. J. 48 (2), 117–145.
Yanagisawa, H., S. Koshimura, K. Goto, T. Miyagi, F. Imamura, A. Ruangrassamee, and C. Tanavud. 2009. The reduction effects of mangrove foreston a tsunami based on field surveys at Pakarang Cape, Thailand and numerical analysis, Estuar .Coast. Self Sci., 81, 27–37.
Yeh, H., 2007. Design tsunami forces for onshore structures. J. Disaster Res. 2 (6), 531–536. Yim, S.C., Yuk, D., Panizzo, A., Risio, M.D., Liu, P.L.-F. Numerical simulations of wave generation by a vertical plunger using RANS and SPH models. J. Waterw. Port Coast. Ocean Eng. 134 (3), 143–159.