MECHANISM AND COUNTERMEASURES OF WAVE OVERTOPPING FOR LONG-PERIOD SWELL IN COMPLEX BATHYMETRY
ICCE 2012 Cover Image
PDF

Keywords

long-period swell
long wave
wave overtoppin

How to Cite

Kashima, H., & Hirayama, K. (2012). MECHANISM AND COUNTERMEASURES OF WAVE OVERTOPPING FOR LONG-PERIOD SWELL IN COMPLEX BATHYMETRY. Coastal Engineering Proceedings, 1(33), currents.45. https://doi.org/10.9753/icce.v33.currents.45

Abstract

Recently, coastal disasters due to long-period swells induced by heavy storms and catastrophic typhoons have increased at Japanese coasts and harbors. Long-period swells are more susceptible to the bottom bathymetry of the offshore deep water region and their wave heights locally increase due to the concentration of wave energy caused by the complex bottom bathymetry in the relatively shallow water region. In addition, the wave overtopping rate may increase due to the long waves in front of the seawall induced by the long-period swells. However, the spatial relationship between wave characteristics and wave overtopping discharges in the complex bathymetry are not well known owing to a lack of detailed measurements. In this study, model experiments were conducted by using a large basin to investigate the spatial characteristics of wave transformation and wave overtopping focusing on the heavy wave overtopping damages caused by the arrivals of long-period swells at the Shimoniikawa Coast in 2008. Effective countermeasures against wave overtopping are also discussed based on their characteristics.
https://doi.org/10.9753/icce.v33.currents.45
PDF

References

Fukase, Y., R. Suminda, Y. Tajima and S. Satoh. 2009. Deformation of long-period giant waves on the Shimoniikawa coast, Journal of JSCE, Ser. B2 (Coastal Engineering), Vol.65, 1411-1415 (in Japanese).

Fukase, Y., R. Suminda, Y. Tajima and S. Satoh. 2010. Mechanism and countermeasures for local amplification of long period waves due to alongshore change in nearshore bathymetry, Journal of JSCE, Ser. B2 (Coastal Engineering), Vol.66, 21-25 (in Japanese).

Hirayama, K., H. Kashima and T. Hiraishi. 2008. Examples of unexpected high waves in shallow water in Japan, Proceedings of Rogue Waves 2008, 49-58.

Hirayama, K., H. Kashima and K. Nakai. 2009. A study on characteristics of long period swell spectrum and its grouping, Annual Journal of Civil Engineering in the Ocean, JSCE, Vol.25, 635-640 (in Japanese).

Janssen, T. T. and J. A. Battjes. 2003. Long waves induced by short-wave groups over a sloping bottom, Journal of Geophysical Research, Vol.108, C8, 14 pp.

Kashima, H., K. Hirayama, T. Hiraishi and K. Shimizu. 2009, Estimation of encounter timing of swell by using nationwide wave observation system (NOWPHAS), Technical Note of The Port and Airport Research Institute, No.1191, 21 pp. (in Japanese).

Kashima, H. and K. Hirayama. 2009. Effects of bottom topography characteristics on transformations of long period swell, in: Proceedings of the 4th SCACR - International Short Conference on Applied Coastal Research, 197-205. ISBN 978-3-00-030141-4. Barcelona, Spain.

Kashima, H. and K. Hirayama. 2010, Experiments on wave overtopping rate and wave pressure on seawalls of long period swell, Technical Note of The Port and Airport Research Institute, No.1218, 26 pp. (in Japanese).

Kawasaki, K., N. Mizutani, K. Iwata, T. Kobayashi, M. Yuhi, T. Saitoh, T. Kitano, H. Sumi, H. Mase and T. Yasuda. 2008. Field survey of damage due to February 2008 high wave on east coast of Toyama Prefecture, Annual Journal of Coastal Engineering, JSCE, Vol.55, 151-155 (in Japanese).http://dx.doi.org/10.2208/proce1989.55.151

Tajima, Y., H. Ishizashi and S. Satoh. 2009. Concentration of slowly-varying nearshore waves and currents around the edge of two different bottom slopes, Journal of JSCE, Ser. B2 (Coastal Engineering), Vol.65, 211-215 (in Japanese).

List, J.H. 1992. Wave groupiness variation in the nearshore, Coastal Engineering, Vol.15, 475-496.http://dx.doi.org/10.1016/0378-3839(91)90024-B

Authors retain copyright and grant the Proceedings right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this Proceedings.