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A platform for research: civil engineering, architecture and urbanism
Interacting Behavior of Nourished Sand and Gravel Along the Nami-Ita Coast, Japan
https://orcid.org/http://orcid.org/0000-0002-1856-4723
At the Nami-ita Coast in Iwate prefecture, Japan, a beautiful white sandy beach was mostly lost by the tsunami and land subsidence due to the 2011 Great East Japan Earthquake. Large-scale beach nourishment was implemented from 2019 to 2021 to recover the beach. In this nourishment, the northern part of the beach was nourished by gravel with a median diameter of 15 cm. In the southern part of the beach, the same gravel was first placed, and then the developed gravel layer was covered by sand. The shoreline location of the nourished sand beach was recovered to the original location before the 2011 event. After a while, however, the surface of nourished sandy beach was covered by a significant amount of gravel. In this study, such drastic change of nourished beach was monitored by field interval cameras, and characteristics of the movement of the gravel were analyzed based on obtained images. It was clarified that the gravel had been transported southward along the shore, and a considerable amount of gravel in the sea was transported and accumulated on the land during high waves. This southward migration was correlated with longshore currents and sediment transport, and the observed distance of gravel migration was well reproduced by time-integral of the longshore currents or sediment transport rates with a threshold of initiation of gravel movement specified by the breaking wave height.
Interacting Behavior of Nourished Sand and Gravel Along the Nami-Ita Coast, Japan
https://orcid.org/http://orcid.org/0000-0002-1856-4723
At the Nami-ita Coast in Iwate prefecture, Japan, a beautiful white sandy beach was mostly lost by the tsunami and land subsidence due to the 2011 Great East Japan Earthquake. Large-scale beach nourishment was implemented from 2019 to 2021 to recover the beach. In this nourishment, the northern part of the beach was nourished by gravel with a median diameter of 15 cm. In the southern part of the beach, the same gravel was first placed, and then the developed gravel layer was covered by sand. The shoreline location of the nourished sand beach was recovered to the original location before the 2011 event. After a while, however, the surface of nourished sandy beach was covered by a significant amount of gravel. In this study, such drastic change of nourished beach was monitored by field interval cameras, and characteristics of the movement of the gravel were analyzed based on obtained images. It was clarified that the gravel had been transported southward along the shore, and a considerable amount of gravel in the sea was transported and accumulated on the land during high waves. This southward migration was correlated with longshore currents and sediment transport, and the observed distance of gravel migration was well reproduced by time-integral of the longshore currents or sediment transport rates with a threshold of initiation of gravel movement specified by the breaking wave height.
Interacting Behavior of Nourished Sand and Gravel Along the Nami-Ita Coast, Japan
https://orcid.org/http://orcid.org/0000-0002-1856-4723
At the Nami-ita Coast in Iwate prefecture, Japan, a beautiful white sandy beach was mostly lost by the tsunami and land subsidence due to the 2011 Great East Japan Earthquake. Large-scale beach nourishment was implemented from 2019 to 2021 to recover the beach. In this nourishment, the northern part of the beach was nourished by gravel with a median diameter of 15 cm. In the southern part of the beach, the same gravel was first placed, and then the developed gravel layer was covered by sand. The shoreline location of the nourished sand beach was recovered to the original location before the 2011 event. After a while, however, the surface of nourished sandy beach was covered by a significant amount of gravel. In this study, such drastic change of nourished beach was monitored by field interval cameras, and characteristics of the movement of the gravel were analyzed based on obtained images. It was clarified that the gravel had been transported southward along the shore, and a considerable amount of gravel in the sea was transported and accumulated on the land during high waves. This southward migration was correlated with longshore currents and sediment transport, and the observed distance of gravel migration was well reproduced by time-integral of the longshore currents or sediment transport rates with a threshold of initiation of gravel movement specified by the breaking wave height.
Interacting Behavior of Nourished Sand and Gravel Along the Nami-Ita Coast, Japan
Lecture Notes in Civil Engineering
Tajima, Yoshimitsu (editor) / Aoki, Shin-ichi (editor) / Sato, Shinji (editor) / Miwa, Takeshi (author) / Tajima, Yoshimitsu (author)
International Conference on Asian and Pacific Coasts ; 2023 ; Kyoto, Japan
Proceedings of the 11th International Conference on Asian and Pacific Coasts ; Chapter: 66 ; 725-734
2024-06-19
10 pages
Article/Chapter (Book)
Electronic Resource
English
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