Wave and Tidal Controls on Embayment Circulation and Headland Bypassing for an Exposed, Macrotidal Site
Headland bypassing is the transport of sediment around rocky headlands by wave and tidal action, associated with high-energy conditions and embayment circulation (e.g., mega-rips). Bypassing may be a key component in the sediment budget of many coastal cells, the quantification of which is required...
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| Format: | Article |
| Language: | English |
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MDPI AG
2018-08-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | http://www.mdpi.com/2077-1312/6/3/94 |
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| author | R. Jak McCarroll Gerd Masselink Nieves G. Valiente Tim Scott Erin V. King Daniel Conley |
| author_facet | R. Jak McCarroll Gerd Masselink Nieves G. Valiente Tim Scott Erin V. King Daniel Conley |
| author_sort | R. Jak McCarroll |
| collection | DOAJ |
| description | Headland bypassing is the transport of sediment around rocky headlands by wave and tidal action, associated with high-energy conditions and embayment circulation (e.g., mega-rips). Bypassing may be a key component in the sediment budget of many coastal cells, the quantification of which is required to predict the coastal response to extreme events and future coastal change. Waves, currents, and water levels were measured off the headland of a sandy, exposed, and macrotidal beach in 18-m and 26-m depths for 2 months. The observations were used to validate a Delft3D morphodynamic model, which was subsequently run for a wide range of scenarios. Three modes of bypassing were determined: (i) tidally-dominated control during low–moderate wave conditions [flux O (0–102 m3 day−1)]; (ii) combined tidal- and embayment circulation controls during moderate–high waves [O (103 m3 day−1)]; and (iii) multi-embayment circulation control during extreme waves [O (104 m3 day−1)]. A site-specific bypass parameter is introduced, which accurately (R2 = 0.95) matches the modelled bypass rates. A 5-year hindcast predicts bypassing is an order of magnitude less than observed cross-shore fluxes during extreme events, suggesting that bypassing at this site is insignificant at annual timescales. This work serves a starting point to generalise the prediction of headland bypassing. |
| first_indexed | 2024-12-17T00:41:31Z |
| format | Article |
| id | doaj.art-2d385a119f0440d0a68666b82b060061 |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-12-17T00:41:31Z |
| publishDate | 2018-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-2d385a119f0440d0a68666b82b0600612022-12-21T22:10:01ZengMDPI AGJournal of Marine Science and Engineering2077-13122018-08-01639410.3390/jmse6030094jmse6030094Wave and Tidal Controls on Embayment Circulation and Headland Bypassing for an Exposed, Macrotidal SiteR. Jak McCarroll0Gerd Masselink1Nieves G. Valiente2Tim Scott3Erin V. King4Daniel Conley5Coastal Processes Research Group, School of Biological and Marine Sciences, University of Plymouth, PL4 8AA Plymouth, UKCoastal Processes Research Group, School of Biological and Marine Sciences, University of Plymouth, PL4 8AA Plymouth, UKCoastal Processes Research Group, School of Biological and Marine Sciences, University of Plymouth, PL4 8AA Plymouth, UKCoastal Processes Research Group, School of Biological and Marine Sciences, University of Plymouth, PL4 8AA Plymouth, UKCoastal Processes Research Group, School of Biological and Marine Sciences, University of Plymouth, PL4 8AA Plymouth, UKCoastal Processes Research Group, School of Biological and Marine Sciences, University of Plymouth, PL4 8AA Plymouth, UKHeadland bypassing is the transport of sediment around rocky headlands by wave and tidal action, associated with high-energy conditions and embayment circulation (e.g., mega-rips). Bypassing may be a key component in the sediment budget of many coastal cells, the quantification of which is required to predict the coastal response to extreme events and future coastal change. Waves, currents, and water levels were measured off the headland of a sandy, exposed, and macrotidal beach in 18-m and 26-m depths for 2 months. The observations were used to validate a Delft3D morphodynamic model, which was subsequently run for a wide range of scenarios. Three modes of bypassing were determined: (i) tidally-dominated control during low–moderate wave conditions [flux O (0–102 m3 day−1)]; (ii) combined tidal- and embayment circulation controls during moderate–high waves [O (103 m3 day−1)]; and (iii) multi-embayment circulation control during extreme waves [O (104 m3 day−1)]. A site-specific bypass parameter is introduced, which accurately (R2 = 0.95) matches the modelled bypass rates. A 5-year hindcast predicts bypassing is an order of magnitude less than observed cross-shore fluxes during extreme events, suggesting that bypassing at this site is insignificant at annual timescales. This work serves a starting point to generalise the prediction of headland bypassing.http://www.mdpi.com/2077-1312/6/3/94embayed beachsediment fluxmega-ripDelft3D |
| spellingShingle | R. Jak McCarroll Gerd Masselink Nieves G. Valiente Tim Scott Erin V. King Daniel Conley Wave and Tidal Controls on Embayment Circulation and Headland Bypassing for an Exposed, Macrotidal Site Journal of Marine Science and Engineering embayed beach sediment flux mega-rip Delft3D |
| title | Wave and Tidal Controls on Embayment Circulation and Headland Bypassing for an Exposed, Macrotidal Site |
| title_full | Wave and Tidal Controls on Embayment Circulation and Headland Bypassing for an Exposed, Macrotidal Site |
| title_fullStr | Wave and Tidal Controls on Embayment Circulation and Headland Bypassing for an Exposed, Macrotidal Site |
| title_full_unstemmed | Wave and Tidal Controls on Embayment Circulation and Headland Bypassing for an Exposed, Macrotidal Site |
| title_short | Wave and Tidal Controls on Embayment Circulation and Headland Bypassing for an Exposed, Macrotidal Site |
| title_sort | wave and tidal controls on embayment circulation and headland bypassing for an exposed macrotidal site |
| topic | embayed beach sediment flux mega-rip Delft3D |
| url | http://www.mdpi.com/2077-1312/6/3/94 |
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