TY - JOUR AU - Ishikawa, Toshinori AU - Uda, Takaaki AU - Hosokawa, Jun-ichi AU - San-nami, Toshiro PY - 2020/12/31 Y2 - 2024/03/29 TI - RECOVERY OF SANDY BEACH AFTER TYPHOON WAVES - CASE STUDY ON CHIGASAKI COAST JF - Coastal Engineering Proceedings JA - Int. Conf. Coastal. Eng. VL - IS - 36v SE - Full Length Papers DO - 10.9753/icce.v36v.papers.42 UR - https://icce-ojs-tamu.tdl.org/icce/article/view/10352 SP - papers.42 AB - <html>Beach topography quickly changes in response to the action of storm waves, resulting in erosion of the foreshore with accretion under a calm wave condition after a storm. These seasonal beach changes may occur on beaches with protective measures or artificial beaches produced by beach nourishment. On these beaches, the shore protection function of a sandy beach is reduced when a trough is formed immediately offshore of the shoreline and the foreshore slope increases, indicating the importance of the study on topographic changes. Moreover, the time required for a beach recovery in response to wave conditions has not been sufficiently studied, along with the 3-D topographic changes associated with beach cycles. In this study, we aim to investigate these issues using the Narrow Multi-Beam survey data, wave data, and seabed materials data, taking the Chigasaki coast as an example. It was found that a seabed shallower than 2 and 3 m depths was eroded by rapid offshore sand transport during a storm event with the deposition of sand in a zone between 3 and 5 m depths, and then the beach recovered within 1-2 years after the storm. It was also confirmed that a bar and trough disappeared in 1-2 months under the conditions of HE = 0.5 m, TE = 8 s, and H/L = 0.005 when the crown depth of the bar was smaller than approximately 2 m. Thus, the topography after the storm waves recovers within several months or 1-2 years depending on wave conditions and the crown depth of the bar.<br><br><b>Recorded Presentation from the vICCE (YouTube Link): <a href="https://youtu.be/W_P_3p_xd8U">https://youtu.be/W_P_3p_xd8U</a></b></html> ER -