Natural Hazards

, Volume 92, Issue 1, pp 327–346 | Cite as

Simplified formulae for designing coastal forest against tsunami run-up: one-dimensional approach

  • Nguyen Ba Thuy
  • N. A. K. Nandasena
  • Vu Hai Dang
  • Norio Tanaka
Original Paper
  • 57 Downloads

Abstract

In the present study, laboratory experiments were conducted to validate the applicability of a numerical model based on one-dimensional nonlinear long-wave equations. The model includes drag and inertia resistance of trees to tsunami flow and porosity between trees and a simplified forest in a wave channel. It was confirmed that the water surface elevation and flow velocity by the numerical simulations agree well with the experimental results for various forest conditions of width and tree density. Further, the numerical model was applied to prototype conditions of a coastal forest of Pandanus odoratissimus to investigate the effects of forest conditions (width and tree density) and incident tsunami conditions (period and height) on run-up height and potential tsunami force. The modeling results were represented in curve-fit equations with the aim of providing simplified formulae for designing coastal forest against tsunamis. The run-up height and potential tsunami forces calculated by the curve-fit formulae and the numerical model agreed within ± 10% error.

Keywords

Tsunami run-up Coastal forest Pandanus odoratissimus Tsunami force 

Notes

Acknowledgements

This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under Grant Number 105.06-2017.07 (numerical method), and partially funded by Ministry of Science and Technology under grant number ĐTĐL-C.35/15 (long wave like abnormal water level), to which the authors are gratefully acknowledged.

References

  1. Chakrabati SK (1991) Wave force on offshore structures. In: Herbich JB (ed) Handbook of coastal and ocean engineering, vol 2. Gulf Publishing Company, Houston, pp 1–54Google Scholar
  2. Danielsen F, Sorensen MK, Olwig MF et al (2005) The Asian tsunami: a protective role for coastal vegetation. Science 310:643CrossRefGoogle Scholar
  3. Imamura F, Goto K, Ohkubo S (2008) A numerical model of the transport of a boulder by tsunami. J Geophys Res 113:C01008CrossRefGoogle Scholar
  4. Kathiresan K, Rajendran N (2005) Coastal mangrove forests mitigated tsunami. Estuar Coast Shelf Sci 65:601–606CrossRefGoogle Scholar
  5. Kerr AM, Baird HB (2007) Natural barriers to natural disasters. Bioscience 57(2):102–103CrossRefGoogle Scholar
  6. Mascarenhas A, Jayakumar S (2008) An environmental perspective of the post-tsunami scenario along the coast of Tamil Nadu, India: role of sand dunes and forests. J Environ Manag 89:24–34CrossRefGoogle Scholar
  7. Nandasena NAK, Tanaka N, Tanimoto K (2008) Tsunami current inundation of ground with coastal vegetation effects; an initial step towards a natural solution for tsunami amelioration. J Earthq Tsunami 2(2):157–171CrossRefGoogle Scholar
  8. Nandasena NAK, Sasaki Y, Tanaka N (2012) Modeling field observations of the 2011 Great East Japan tsunami: efficacy of artificial and natural structures on tsunami mitigation. Coast Eng 67:1–13CrossRefGoogle Scholar
  9. Nepf HM (1999) Drag, turbulence, and diffusion in flow through emergent vegetation. Water Resour Res 35(2):479–489CrossRefGoogle Scholar
  10. Shuto N (1987) The effectiveness and limit of tsunami control forests. Coast Eng Jpn 30(1):143–153Google Scholar
  11. Tanaka N (2009) Vegetation bioshields for tsunami mitigation: review of the effectiveness, limitations, construction, and sustainable management. Landsc Ecol Eng 5:71–79CrossRefGoogle Scholar
  12. Tanaka N, Onai A (2016) Mitigation of destructive fluid force on buildings due to trapping of floating debris by coastal forest during the Great East Japan tsunami. Landsc Ecol Eng 13:131–144CrossRefGoogle Scholar
  13. Tanaka N, Sasaki Y, Mowjood MIM, Jinadasa KBSN (2007) Coastal vegetation structures and their functions in tsunami protection: experience of the recent Indian Ocean tsunami. Landsc Ecol Eng 3:33–45CrossRefGoogle Scholar
  14. Tanaka N, Nandasena NAK, Jinadasa KSBN, Sasaki Y, Tanimoto K, Mowjood MIM (2009) Developing effective vegetation bioshield for tsunami protection. J Civ Environ Eng Syst 26:163–180CrossRefGoogle Scholar
  15. Tanaka N, Yasuda S, Iimura K, Yagisawa J (2014) Combined effects of coastal forest and sea embankment on reducing the washout region of houses in the Great East Japan tsunami. J Hydro-Environ Res 8:270–280CrossRefGoogle Scholar
  16. Tanimoto K, Tanaka N, Nandasena NAK, Iimura K, Shimizu T (2007) Numerical simulation of tsunami prevention by coastal forest with several species of tropical tree. Annu J Coast Eng 54(2):1381–1385 (in Japanese) Google Scholar
  17. Thuy NB, Tanimoto K, Tanaka N, Harada K, Iimura K (2009a) Effect of open gap in coastal forest on tsunami run-up—investigations by experiment and numerical simulation. Ocean Eng 36:1258–1269CrossRefGoogle Scholar
  18. Thuy NB, Tanaka N, Tanimoto K, Harada K, Iimura K (2009b) Tsunami flow behind the coastal forest with an open gap-effects of tsunami and tree condition. In: Proceedings of the 6th international conference on coastal dynamic, Tokyo-Japan (CD-Rom).  https://doi.org/10.1142/9789814282475_0050
  19. Thuy NB, Tanimoto K, Tanaka N (2010) Flow and potential force due to runup tsunami around a coastal forest with a gap—experiments and numerical simulations. Int J Sci Tsunami Hazards 29:43–69Google Scholar
  20. Thuy NB, Tanaka N, Tanimoto K (2012) Tsunami mitigation by coastal vegetation considering the effect of tree breaking. J Coast Conserv 16:111–121.  https://doi.org/10.1007/s11852-011-0179-7 CrossRefGoogle Scholar
  21. Thuy NB, Nandasena NAK, Dang VH, Kim S, Hien NX, Hole LR, Thai TH (2017) Effect of river vegetation with timber piling on ship wave attenuation: investigation by field survey and numerical modeling. Ocean Eng 129:37–45CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  • Nguyen Ba Thuy
    • 1
  • N. A. K. Nandasena
    • 2
  • Vu Hai Dang
    • 3
  • Norio Tanaka
    • 4
  1. 1.Vietnam National Hydrometeorological Forecasting CenterHanoiVietnam
  2. 2.Department of Civil and Environmental Engineering, Faculty of EngineeringUniversity of AucklandAucklandNew Zealand
  3. 3.Institute of Marine Geophysics and GeologyHanoiVietnam
  4. 4.Graduate School of Science and EngineeringSaitama UniversitySaitamaJapan

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