Elongation of Sand Spit and Profile Changes on Sloping Shallow Seabed

Long-Term Topographic Changes Around Sand Spit and Impact of Extraordinary High Waves During Typhoons

“…16, sand was deposited up to a depth of 45 m, which is 3.8 times greater than the depth of closure along transect No. 12, while maintaining a very steep slope of 1/2, and the profile moved offshore in parallel with each other, as studied by Miyahara et al (2015). Along transect No.…”

“…As a measure against beach erosion, an artificial headland (HL) composed of two detached breakwaters and the breakwaters (BWs) placed along the shoreline have been constructed along with beach nourishment, but the beach is barely maintained by these measures at present. In 2013, two large typhoons hit the coast and extraordinary high waves were incident to the coast, causing rapid beach changes around the structures, and these beach changes were superimposed on the long-term topographic changes that have occurred over a long time as a geomorphological process as described in Miyahara et al (2015). The understanding of these long-term and short-term topographic changes with different time scales is important in considering the conservation of the sand spit.…”

Field Observation and Numerical Simulation of Barrier Island Formation as Result of Elongation of Sand Spit and Its Attachment to Opposite Shore

“…Before the attachment of the tip of the sand spit to the opposite shore, sand transport was considered to be negligibly small because of the discontinuity of the shoreline. To analyze the process near the tip of the sand spit, results of numerical simulation by Sannami et al (2014) and Miyahara et al (2015) were evaluated, in which similar topographic changes as those in the Nabeshima area were predicted using the BG model. Here, results from both research groups were compared in terms of the topographic changes around the tip of the sand spit.…”

Formation of Sand Spit and Bay Barrier

“…As further applications of the Type 3 BG model, (1) the model was used to predict the elongation of sand spit and profile changes on sloping shallow seabed under waves [16], (2) field observation on the formation of a barrier island as a result of elongation of sand spit was studied in Nabeshima area facing Nakatsu tidal flat in the Suonada Sea, and their formation was numerically predicted using the Type 3 BG model [17]. 3The deformation of an isolated offshore sandbar on tidal flat and merging with beach owing to waves was also predicted using the Type 3 BG model in [18].…”