PREDICTION OF BEACH EROSION CAUSED BY REDUCTION OF FLUVIAL SAND SUPPLY DUE TO EXCESS SAND MINING AND BEACH RECOVERY AFTER PROHIBITION OF MINING

Toshiro San-nami, Takaaki Uda, Norikazu Ohashi, Hitoshi Iwamoto, Masumi Serizawa, Toshinori Ishikawa, Shiho Miyahara

Abstract


Long-term topographic changes since 1968 along the entire Shizuoka and Shimizu coasts including a 17 km stretch extending between the Abe River mouth and the tip of the Mihono-matsubara sand spit were investigated. Beach erosion of these coasts was triggered by the decrease in sediment supply from the Abe River due to excessive riverbed mining until 1967. After 1982/1983, natural sand supply from the river increased and accretion occurred on these coasts. Measured topographic changes were reproduced using the contour-line-change model considering changes in grain size. Not only the movement of the sand body but also the shoreline and bathymetric changes were numerically reproduced. The calculated results were in good agreement with the measured topographic changes.

Keywords


beach erosion; sand body; contour-line-change model; Shizuoka coast; sand mining

References


Fukuhama, M., T. Uda, K. Yamada, M. Serizawa, T. San-nami, and T. Ishikawa. 2009. Prediction of development of sand body and movement of fine sand offshore of detached breakwaters, Proc. Coastal Dynamics 2009, Paper No. 39, pp. 1-12.

Miyahara, S., T. Uda, K. Furuike, M. Serizawa, T. San-nami, and T. Ishikawa. 2010. Effect of sand bypassing at Sakuma dam in Tenryu River as a measure against erosion of Tenryu delta coast, Proc. 32nd ICCE, sediment.106, pp.1-12.

Nishitani, M., T. Uda, M. Serizawa, and T. Ishikawa. 2008. Measurement and prediction of deformation of conveyer belts carrying gravel and fine sand off Shimizu coast, Proc. 31st ICCE, pp. 2570-2582.

Ozasa, H., and A. H. Brampton. 1980. Model for predicting the shoreline evolution of beaches backed by seawalls, Coastal Eng., Vol. 4, pp. 47-64.http://dx.doi.org/10.1016/0378-3839(80)90005-8

Sakai, K., T. Uda, M. Serizawa, T. Kumada, and Y. Kanda. 2006. Model for predicting threedimensional sea bottom topography of statically stable beach, Proc. 30th ICCE, pp. 3184-3196.

Uda, T., and S. Kawano. 1996. Development of a predictive model of contour line change due to waves, Proc. JSCE, No. 539/􁶘-35, pp. 121-139. (in Japanese)

Uda, T., M. Serizawa, M. Nishitani, and T. Ishikawa. 2008. Field investigation and numerical simulation of movement of sand body, Proc. 31st ICCE, pp. 2051-2063.

Uda, T., and M. Serizawa. 2010. Model for predicting topographic changes on coast composed of sand of mixed grain size and its applications, in 'Numerical simulations - examples and applications in computational fluid dynamics' Angermann, L. ed., INTEC, pp. 327-358.http://dx.doi.org/10.5772/12926

Uda, T. 2010. Japan's Beach Erosion - Reality and Future Measures, World Scientific, 418 pp.


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