Recent Shoreline Changes Due to High-Angle Wave Instability along the East Coast of Lingayen Gulf in the Philippines
A small perturbation on the shoreline may develop under high-angle wave conditions, resulting in the formation of sand spits along the shoreline. Serizawa et al. explained the development of sand spits caused by the instability mechanism using the BG model (a model for predicting 3-D beach changes b...
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MDPI AG
2021-03-01
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| Series: | Geosciences |
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| Online Access: | https://www.mdpi.com/2076-3263/11/3/144 |
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| author | Takaaki Uda Yasuhito Noshi |
| author_facet | Takaaki Uda Yasuhito Noshi |
| author_sort | Takaaki Uda |
| collection | DOAJ |
| description | A small perturbation on the shoreline may develop under high-angle wave conditions, resulting in the formation of sand spits along the shoreline. Serizawa et al. explained the development of sand spits caused by the instability mechanism using the BG model (a model for predicting 3-D beach changes based on Bagnold’s concept). However, examples of the development of sand spits caused by this mechanism in the field are limited in number. Lingayen Gulf in the Philippines has a large aspect ratio, so shoreline instability occurs along the coastline, significantly affecting the shore protection along the coast. In this study, the shoreline instability along the river delta coasts around the Balili and Aringay Rivers flowing into Lingayen Gulf and a sand spit were investigated using satellite images together with field observation. The shoreline changes observed south of the Aringay River mouth were compared with those observed in a previous study on the development of a sand spit by San-nami et al. The rate of longshore sand transport to form a sand spit at Santo Tomas in Lingayen Gulf was estimated to be approximately 1.3 × 10<sup>5</sup> m<sup>3</sup>/yr, which is in good agreement with the value measured on the Shimizu coast in Suruga Bay, with a comparable aspect ratio of 1.2 relative to 1.3 in Lingayen Gulf. It was concluded that shoreline undulations have evolved downcoast of two river deltas owing to high-angle wave instability along the east coast of Lingayen Gulf and the formation of a sand spit has occurred. A soft measure, such as sand bypassing, would be better to be adopted along the coasts in Lingayen Gulf instead of hard measures against erosion, to prevent rapid expansion of an artificial, protected coastline. |
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| institution | Directory Open Access Journal |
| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-03-10T13:00:35Z |
| publishDate | 2021-03-01 |
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| spelling | doaj.art-0ae795f12bf44879b6e6105b59cb27572023-11-21T11:32:15ZengMDPI AGGeosciences2076-32632021-03-0111314410.3390/geosciences11030144Recent Shoreline Changes Due to High-Angle Wave Instability along the East Coast of Lingayen Gulf in the PhilippinesTakaaki Uda0Yasuhito Noshi1Public Works Research Center, Taito, Tokyo 110-0016, JapanDepartment of Oceanic Architecture and Engineering, College of Science and Technology, Nihon University, Funabashi, Chiba 274-8501, JapanA small perturbation on the shoreline may develop under high-angle wave conditions, resulting in the formation of sand spits along the shoreline. Serizawa et al. explained the development of sand spits caused by the instability mechanism using the BG model (a model for predicting 3-D beach changes based on Bagnold’s concept). However, examples of the development of sand spits caused by this mechanism in the field are limited in number. Lingayen Gulf in the Philippines has a large aspect ratio, so shoreline instability occurs along the coastline, significantly affecting the shore protection along the coast. In this study, the shoreline instability along the river delta coasts around the Balili and Aringay Rivers flowing into Lingayen Gulf and a sand spit were investigated using satellite images together with field observation. The shoreline changes observed south of the Aringay River mouth were compared with those observed in a previous study on the development of a sand spit by San-nami et al. The rate of longshore sand transport to form a sand spit at Santo Tomas in Lingayen Gulf was estimated to be approximately 1.3 × 10<sup>5</sup> m<sup>3</sup>/yr, which is in good agreement with the value measured on the Shimizu coast in Suruga Bay, with a comparable aspect ratio of 1.2 relative to 1.3 in Lingayen Gulf. It was concluded that shoreline undulations have evolved downcoast of two river deltas owing to high-angle wave instability along the east coast of Lingayen Gulf and the formation of a sand spit has occurred. A soft measure, such as sand bypassing, would be better to be adopted along the coasts in Lingayen Gulf instead of hard measures against erosion, to prevent rapid expansion of an artificial, protected coastline.https://www.mdpi.com/2076-3263/11/3/144PhilippinesLingayen GulfSuruga Bayhigh-angle wavessand spitshoreline instability |
| spellingShingle | Takaaki Uda Yasuhito Noshi Recent Shoreline Changes Due to High-Angle Wave Instability along the East Coast of Lingayen Gulf in the Philippines Geosciences Philippines Lingayen Gulf Suruga Bay high-angle waves sand spit shoreline instability |
| title | Recent Shoreline Changes Due to High-Angle Wave Instability along the East Coast of Lingayen Gulf in the Philippines |
| title_full | Recent Shoreline Changes Due to High-Angle Wave Instability along the East Coast of Lingayen Gulf in the Philippines |
| title_fullStr | Recent Shoreline Changes Due to High-Angle Wave Instability along the East Coast of Lingayen Gulf in the Philippines |
| title_full_unstemmed | Recent Shoreline Changes Due to High-Angle Wave Instability along the East Coast of Lingayen Gulf in the Philippines |
| title_short | Recent Shoreline Changes Due to High-Angle Wave Instability along the East Coast of Lingayen Gulf in the Philippines |
| title_sort | recent shoreline changes due to high angle wave instability along the east coast of lingayen gulf in the philippines |
| topic | Philippines Lingayen Gulf Suruga Bay high-angle waves sand spit shoreline instability |
| url | https://www.mdpi.com/2076-3263/11/3/144 |
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