LONG-TERM MONITORING ON THE SAND SPIT MORPHODYNAMICS AT THE TENRYU RIVER MOUTH

Haijiang Liu, Yoshimitsu Tajima, Shinji Sato

Abstract


In this study, long-term monitoring on the sand spit morphodynamics at the Tenryu River mouth was carried out based on the time series of sand spit profiles extracted from the field camera recorded images between Apr 2007 and Dec 2009. Time stack images were applied to qualitatively characterize the variation of sand spit morphology at the representative longshore location. Primarily analyses were conducted by focusing on the bulk statistical properties of the recorded sand spit profile data. Detailed insight into the evolution process of the sand spit shoreline location was estimated through the Empirical Orthogonal Function (EOF) analysis. Sand spit riverside morphodynamics presents a short-term, but intensive variation pattern and is found to be closely related to the overtopping or flood events. Modification on the sand spit shoreline location shows an asymmetric nearshore process. In the first two years, slow beach accretion accompanying with the eastward longshore sand movement prevailed; whereas, rapid shoreline erosion, together with the westward longshore sand movement, became predominant in the following half year.

Keywords


sand spit morphodynamics; image analysis; time stack image; bulk statistical analysis; EOF

References


Aarninkhof, S.G.J. 2003. Nearshore bathymetry derived from video imagery. PhD thesis, Delft University of Technology, Delft University Press, Delft, 175 pp.

Aubrey, D.G. 1979. Seasonal patterns of onshore/offshore sediment movement. J. Geophys. Res., 84(C10), 6347-6354. http://dx.doi.org/10.1029/JC084iC10p06347

Fairley I., M. Davidson, K. Kingston, T. Dolphin, and R. Phillips. 2009. Empirical orthogonal function analysis of shoreline changes behind two different designs of detached breakwaters. Coastal Engineering, 56(11-12), 1097-1108.http://dx.doi.org/10.1016/j.coastaleng.2009.08.001

Hansen, J.E., and P.L. Barnard. 2010. Sub-weekly to interannual variability of a high-energy shoreline. Coastal Engineering, in press. http://dx.doi.org/10.1016/j.coastaleng.2010.05.011

Holland, K.T., R.A. Holman, T.C. Lippmann, and J. Stanley. 1997. Practical use of video imagery in nearshore oceanographic field studies. IEEE J. of Oceanic Eng., 22(1), 81-92. http://dx.doi.org/10.1109/48.557542

Holman, R.A., and J. Stanley. 2007. The history and technical capabilities of Argus. Coastal Engineering, 54(6-7), 477-491. http://dx.doi.org/10.1016/j.coastaleng.2007.01.003

Larson, M., M. Capobianco, H. Jansen, G. Rozynski, H.N. Soughgate, M. Stive, K.M. Wijnberg, and S.

Hulscher. 2003. Analysis and modeling of field data on coastal morphological evolution over yearly and decadal time scales. Part 1: Background and linear techniques. J. of Coastal Research, 19(4), 760-775.

Liu, H., S. Sato, Y. Tajima, G. Huang, and H. Fujiwara. 2007. Investigation on the historical evolution of alluvial deposits along the Tenryu River and the Enshu Coast. Proceedings of the 4 th Asian and Pacific Coastal Engineering Conference, Nanjing, China, 1139-1150.

Liu, H., Y. Tajima, and S. Sato. 2008. Field study on the nearshore sediment process around the Tenryu estuary using image analysis, Proceedings of 31 st International Conference on Coastal Engineering, Hamburg, Germany, 2064-2076. PMCid:2538881

Miller J.K., and R.G. Dean. 2007. Shoreline variability via empirical orthogonal function analysis: Part I temporal and spatial characteristics. Coastal Engineering, 54(2), 111-131. http://dx.doi.org/10.1016/j.coastaleng.2006.08.013

Plant, N.G., S.G.J. Aarninkhof, I.L. Turner, and K.S. Kingston. 2007. The performance of shoreline detection models applied to video imagery. J. of Coastal Research, 23(3), 658-670. http://dx.doi.org/10.2112/1551-5036(2007)23[658:TPOSDM]2.0.CO;2

Southgate, H.N., K.M. Wijnberg, M. Larson, M. Capobianco, and H. Jansen. 2003. Analysis of field data of coastal morphological evolution over yearly and decadal timescales. Part 2: Non-linear techniques. J. of Coastal Research, 19(4), 776-789.

Takagawa, T., Y. Tajima, H. Liu, S. Takewaka, and S. Sato. 2011. Dynamic topography changes of sand spit of the Tenryu River mouth due to overtopping waves. Proceedings of Coastal sediments' 11, Miami, Florida, USA, accepted.

Winant, C.D., D.L. Inman, and C.E. Nordstrom. 1975. Description of seasonal beach changes using empirical eigenfunctions. J. Geophys. Res., 80(15), 1979-1986.http://dx.doi.org/10.1029/JC080i015p01979


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