Abstract
The long-term evolution of the Tenryu River delta associated with sand bypassing at several dams is investigated using the contour-line-change model considering the change in grain size. The effect of the increase in sediment yield from the river mouth on the nearby coasts is numerically predicted. When the sediment yield is artificially increased, the supplied sediment is mainly deposited around the river mouth, resulting in a large shoreline advance, but it takes a longer time for a sandy beach far from the river mouth to recover. Another measure, such as sand bypassing of the coast, is required to recover sandy beaches downcoast.References
Furuike, K., T. Uda, M. Serizawa, T. San-nami and T. Ishikawa. 2009. Model for predicting long-term beach changes originated from accretive features of a natural delta coast, Asian and Pacific Coasts 2009, Proc. 5th Inter. Conf., Vol. 4, 266-272.
Kamphuis, J. W., M. H. Davies, R. B. Narim and O. J. Sayao. 1986. Calculation of littoral sand transport rate, Coastal Engineering, Vol. 10, 1-12. http://dx.doi.org/10.1016/0378-3839(86)90036-0
Kraus, N. C. 1985. Field experiments on vertical mixing of sand in the surf zone, J. Sedimentary Petrology, Vol. 55, 3-14.
Kumada, T., A. Kobayashi, T. Uda and M. Serizawa. 2003. Development of predictive model of shoreline and grain size changes, Coastal Sediments '03, 1-14.
Ozasa, H. and A. H. Brampton. 1980. Model for predicting the shoreline evolution of beaches backed by seawalls, Coastal Eng., 4, 47-64. http://dx.doi.org/10.1016/0378-3839(80)90005-8
Serizawa, M., T. Uda, T. San-nami, K. Furuike and T. Kumada. 2003. Improvement of contour line change model in terms of stabilization mechanism of longitudinal profile, Coastal Sediments '03, 1-15.
Torii, K., S. Sato, T. Uda and T. Okayasu. 2004. Regional sediment management based on sediment budget for graded sediments - a case study of Tenryu watershed and Enshu-nada coast, Proc. 29th ICCE, 3110-3122.
Uda, T. and S. Kawano. 1996. Development of a predictive model of contour line change due to wave, Proc. JSCE, No. 539/II-35, 121-139. (in Japanese)
Uda, T., T. Kumada and M. Serizawa. 2004. Predictive model of change in longitudinal profile in beach nourishment using sand of mixed grain size, Proc. 29th ICCE, 3378-3390.
Uda, T., I. Nagashima, K. Furuike, S. Miyahara and T. Ishikawa. 2008. Impact of sand bypassing at dams in Tenryu River to nearby coasts, Annual Jour. Coastal Eng., JSCE, Vol. 55, 656-660. (in Japanese)