Keywords
parameterization method
solitary wave
wave attenuation
laboratory experiments
How to Cite
Abstract
The systematic laboratory investigation on tsunami attenuation by flexible mangrove models was performed in order to improve the knowledge on tsunami-coastal forest interaction. A sophisticated parameterization method, based on structural and bio-mechanical properties of a mature mangrove (Rhizophora sp.), was developed for the construction of the mangrove models under assumption of stiff and flexible structure. The forest model examined in the laboratory experiments consisted of the selected flexible mangrove models, arranged in different configurations, which was impacted by a tsunami-like solitary wave of varying height, propagating in different water depths. Based on the envelopes of max. wave height and wave forces induced on single tree models, wave evolution modes were determined to identify the source of wave attenuation. The results indicate the dependence of wave transmission on the observed wave evolution modes and relative forest width: the highest transmission coefficient is attributed to nonbreaking waves (ca. 0.78 and 0.55 for forest width of 0.75 and 3.0 m, respectively), while the lowest transmission coefficient corresponds to wave breaking in front of/in the forest model (ca. 0.5 and 0.3 for forest width of 0.75 and 3.0 m, respectively).References
Al-Banaa, K., and P.L.-F. Liu. 2007. Numerical study on the hydraulic performance of submerged porous breakwater under solitary wave attack, Journal of Coastal Research, Special Issue 50, 201-205.
Badola, R., and S.A. Hussain. 2005. Valuing ecosystem functions: an empirical study on the storm protection function of Bhitarkanika mangrove ecosystem, India, Environmental Consecration, 32(1), 85-92.
Clough, B.F., D.T. Tan, D.X. Phuong, and D.C. Buu. 2000. Canopy leaf area index and litter fall in stands of the mangrove Rhizophora apiculata of different age in the Mekong Delta, Vietnam, Aquatic Botany, 66(4), 311-320.
EJF. 2006. Mangroves: nature`s defence against tsunamis - a report on the impact of mangrove loss and shrimp farm development on coastal defences, Environmental Justice Foundation, London, UK.
Green, E., and C. Clark. 2000. Assessing mangrove Leaf Area Index and canopy closure, Remote Sensing Handbook for Tropical Coastal Management, J. Edwards (Ed.), UNESCO-CSI, http://www.unesco.org/csi/pub/source/rs.htm.
Harada, K., and F. Imamura. 2000. Experimental study on the resistance by mangrove under the unsteady flow, Proceedings of the 1st Congress of the Asian and Pacific Coastal Engineering, Dalian, 975-984.
Harada, K., and Y. Kawata. 2005. Study on tsunami reduction effect of coastal forests due to forest growth, Annuals of Disaster Prevention Research Institute, 48C, Tokyo University, Japan, 161-165.
Hawa, S. 2005. The use of bakau as a piling material in Malaysia, Bachelor thesis, Universiti Teknologi Malaysia, 166pp.
Husrin, S. 2013. Modeling of tsunami and storm wave attenuation by coastal forests, Doctoral Thesis, TU Braunschweig, Germany.
Istiyanto, D.C., K.S. Utomo, and Suranto. 2003. Pengaruh Rumpun Bakau Terhadap Perambatan Tsunami di Pantai (The effect of mangrove forest to the attenuation of tsunami in coastal area), Proceedings of Seminar Mengurangi Dampak Tsunami: Kemungkinan Penerapan Hasil Riset, BPPT - JICA, 11 March 2003, Yogyakarta (in Indonesian).
Kathiresan, K., and N. Rajendran. 2005. Coastal mangrove forests mitigated tsunami, Estuarine, Coastal and Shelf Science, 65(3), 601-606.
Kongko, W. 2004. Study on tsunami energy dissipation in mangrove forest, Master Thesis, Iwate University, Japan.
Latief, H., and S. Hadi. 2006. The role of forest and trees in protecting coastal areas against tsunami, Proceedings of the Regional Technical Workshop "Coastal protection in the aftermath of the Indian Ocean tsunami: what role for forests and trees?†, Khao Lak, Thailand.
Liu, P.L.-F., and Y. Cheng. 2001. A numerical study of the evolution of a solitary wave over a shelf, Physics of Fluids, 40(3), 229-240.
Longuet-Higgins, M.S., and J.D. Fenton. 1974. On the mass, momentum, energy and circulation of a solitary wave, Proceedings Royal Society London A, 337, 1-13.
Massel, S.R., K. Furukawa, and R.M. Brinkman. 1999. Surface waves propagation in mangrove forests, Fluid Dynamics Research, 24, 219-249.
Mazda, Y., E. Wolanski, B. King, A. Sase, D. Ohtsuka, and M. Magi. 1997a. Drag force due to vegetation in mangrove swamps, Mangroves and Salt Marshes, 1, 193-199.
Mazda, Y., M. Magi, M. Kogo, and P.N. Hong. 1997b. Mangroves as a coastal protection from waves in the Tong King delta, Vietnam, Mangroves and Salt Marshes, 1, 127-135.
Munk, W. 1949. The solitary wave theory and its application to surf problems, Annals of the New York
Academy of Sciences, 51, 376-424.
Shuto, N. 1987. The effectiveness and limit of tsunami control forests, Coastal Engineering in Japan, 30,143-153.
StrusiÅ,,ska-Correia, A., S. Husrin, and H. Oumeraci. 2013. Tsunami damping by mangrove forest: a laboratory study using parameterized trees, Journal of Natural Hazards and Earth System Sciences, 13, 483-503.
Vallam, S., M. Kantharaj, and N. Lakshmanan. 2011. Resistance of flexible emergent vegetation and their effects on the forces and runup due to waves, In: The Tsunami Threat - Research and Technology, www.intechopen.com, 129-160.
Wolanski, E. 2007. Protective functions of coastal forests and trees against natural hazards. In: Coastal Protection in the Aftermath of the Indian Ocean Tsunami. What Role for Forests and Trees? FAO, Bangkok, 157-179.
Yanagisawa, H., S. Koshimura, K. Goto, T. Miyagi, F. Imamura, A. Ruangrassamee, and C. Tanavud. 2009. The reduction effects of mangrove forest on a tsunami based on field surveys at Pakarang Cape, Thailand and numerical analysis, Estuarine, Coastal and Shelf Science, 81, 27-37.