Littoral Drift Impoundment at a Sandbar Breakwater: Two Case Studies along the Bight of Benin Coast (Gulf of Guinea, West Africa)
This study assessed the deposition of sediment and shoreline evolution at two newly constructed port facilities in the Bight of Benin, West Africa. Based on the Building with Nature approach, the concept of a sandbar breakwater was implemented at the study sites. The coastal system of the bight is c...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-08-01
|
| Series: | Journal of Marine Science and Engineering |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-1312/11/9/1651 |
| _version_ | 1797579347078414336 |
|---|---|
| author | Stephan K. Lawson Keiko Udo Hitoshi Tanaka Janaka Bamunawala |
| author_facet | Stephan K. Lawson Keiko Udo Hitoshi Tanaka Janaka Bamunawala |
| author_sort | Stephan K. Lawson |
| collection | DOAJ |
| description | This study assessed the deposition of sediment and shoreline evolution at two newly constructed port facilities in the Bight of Benin, West Africa. Based on the Building with Nature approach, the concept of a sandbar breakwater was implemented at the study sites. The coastal system of the bight is characterized by a sand barrier-lagoon system and a uniform prevailing wave climate, making it a favorable location for this innovative port solution. The case studies were undertaken at the Port of Lomé, Togo, and the Lekki Deep Sea Port (Dangote Sea Port), Nigeria, using remotely sensed shoreline positions and the one-line coastline change model for different periods. After construction of the breakwater, we estimated that the updrift coastline at the two locations accreted in the range of 10–23 m/year and the rates of sediment deposition were estimated to be in the magnitude of 1.0–7.0 × 10<sup>5</sup> m<sup>3</sup>/year. The comparative study conducted also showed that these rates could further reach a magnitude of 10<sup>6</sup> m<sup>3</sup>/year at other sediment-accreting landforms within the bight. We found that these large magnitudes of longshore sediment transport generated from very oblique incident waves (10°–20°) and sediment input from rivers (in orders of 10<sup>6</sup> m<sup>3</sup>/year) have enabled the realization of expected morphodynamic changes on the updrift shoreline of the ports. From these results, downdrift morphological changes should not be underestimated due to potential imbalances induced in the sedimentary budget along the coastline. Future developmental plans within the bight should also continuously aim to adopt nature-based solutions to protect the ecosystem while mitigating unforeseen implications. |
| first_indexed | 2024-03-10T22:34:49Z |
| format | Article |
| id | doaj.art-1118f8d0f17d47539614b779c3f8893c |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-10T22:34:49Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-1118f8d0f17d47539614b779c3f8893c2023-11-19T11:25:30ZengMDPI AGJournal of Marine Science and Engineering2077-13122023-08-01119165110.3390/jmse11091651Littoral Drift Impoundment at a Sandbar Breakwater: Two Case Studies along the Bight of Benin Coast (Gulf of Guinea, West Africa)Stephan K. Lawson0Keiko Udo1Hitoshi Tanaka2Janaka Bamunawala3Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai 980-8579, JapanDepartment of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai 980-8579, JapanInstitute of Liberal Arts and Sciences, Tohoku University, 41 Kawauchi, Aoba-ku, Sendai 980-8579, JapanDepartment of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai 980-8579, JapanThis study assessed the deposition of sediment and shoreline evolution at two newly constructed port facilities in the Bight of Benin, West Africa. Based on the Building with Nature approach, the concept of a sandbar breakwater was implemented at the study sites. The coastal system of the bight is characterized by a sand barrier-lagoon system and a uniform prevailing wave climate, making it a favorable location for this innovative port solution. The case studies were undertaken at the Port of Lomé, Togo, and the Lekki Deep Sea Port (Dangote Sea Port), Nigeria, using remotely sensed shoreline positions and the one-line coastline change model for different periods. After construction of the breakwater, we estimated that the updrift coastline at the two locations accreted in the range of 10–23 m/year and the rates of sediment deposition were estimated to be in the magnitude of 1.0–7.0 × 10<sup>5</sup> m<sup>3</sup>/year. The comparative study conducted also showed that these rates could further reach a magnitude of 10<sup>6</sup> m<sup>3</sup>/year at other sediment-accreting landforms within the bight. We found that these large magnitudes of longshore sediment transport generated from very oblique incident waves (10°–20°) and sediment input from rivers (in orders of 10<sup>6</sup> m<sup>3</sup>/year) have enabled the realization of expected morphodynamic changes on the updrift shoreline of the ports. From these results, downdrift morphological changes should not be underestimated due to potential imbalances induced in the sedimentary budget along the coastline. Future developmental plans within the bight should also continuously aim to adopt nature-based solutions to protect the ecosystem while mitigating unforeseen implications.https://www.mdpi.com/2077-1312/11/9/1651portsbreakwaterlongshore sediment transportshoreline evolutionone-line modelsediment deposition |
| spellingShingle | Stephan K. Lawson Keiko Udo Hitoshi Tanaka Janaka Bamunawala Littoral Drift Impoundment at a Sandbar Breakwater: Two Case Studies along the Bight of Benin Coast (Gulf of Guinea, West Africa) Journal of Marine Science and Engineering ports breakwater longshore sediment transport shoreline evolution one-line model sediment deposition |
| title | Littoral Drift Impoundment at a Sandbar Breakwater: Two Case Studies along the Bight of Benin Coast (Gulf of Guinea, West Africa) |
| title_full | Littoral Drift Impoundment at a Sandbar Breakwater: Two Case Studies along the Bight of Benin Coast (Gulf of Guinea, West Africa) |
| title_fullStr | Littoral Drift Impoundment at a Sandbar Breakwater: Two Case Studies along the Bight of Benin Coast (Gulf of Guinea, West Africa) |
| title_full_unstemmed | Littoral Drift Impoundment at a Sandbar Breakwater: Two Case Studies along the Bight of Benin Coast (Gulf of Guinea, West Africa) |
| title_short | Littoral Drift Impoundment at a Sandbar Breakwater: Two Case Studies along the Bight of Benin Coast (Gulf of Guinea, West Africa) |
| title_sort | littoral drift impoundment at a sandbar breakwater two case studies along the bight of benin coast gulf of guinea west africa |
| topic | ports breakwater longshore sediment transport shoreline evolution one-line model sediment deposition |
| url | https://www.mdpi.com/2077-1312/11/9/1651 |
| work_keys_str_mv | AT stephanklawson littoraldriftimpoundmentatasandbarbreakwatertwocasestudiesalongthebightofbenincoastgulfofguineawestafrica AT keikoudo littoraldriftimpoundmentatasandbarbreakwatertwocasestudiesalongthebightofbenincoastgulfofguineawestafrica AT hitoshitanaka littoraldriftimpoundmentatasandbarbreakwatertwocasestudiesalongthebightofbenincoastgulfofguineawestafrica AT janakabamunawala littoraldriftimpoundmentatasandbarbreakwatertwocasestudiesalongthebightofbenincoastgulfofguineawestafrica |