EGU21-15834
https://doi.org/10.5194/egusphere-egu21-15834
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Monitoring inner shelf sediment transport using fluorescent sand tracers: an example from the south coast of Portugal 

João Cascalho1,2, Rui Taborda1,2, Marcos Rosa3, Erwan Garel4, Sebastião Teixeira5, Ana Alberto3, and Teresa Drago2,3
João Cascalho et al.
  • 1Departamento de Geologia, Faculdade de Ciências, Universidade Lisboa, Lisboa, Portugal (jpcascalho@fc.ul.pt)
  • 2Instituto Dom Luiz (IDL), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
  • 3Instituto Português do Mar e da Atmosfera, Lisboa, Portugal
  • 4Centro de Investigação Marinha e Ambiental (CIMA), Universidade do Algarve, Faro, Portugal
  • 5Agência Portuguesa do Ambiente, ARH-Algarve, Faro, Portugal

The continuous need for beach nourishment requires a detailed understanding of the sediment transport characteristics at the shelf borrow sites, to assess their recovery rate and to evaluate the long-term sustainability of these operations. 

The main objective of this work is to assess sediment transport conditions at an inner shelf borrow site exploited to nourish a beach located at the updrift boundary of the same sedimentary cell (Belharucas, Albufeira, south coast of Portugal).

The work is supported by a sand tracer experiment, where 600 kg of coated sand with fluorescent ink was deposited (August 2020) by divers at 11 m depth (referred to the mean sea level). Periodic sediment sampling using a Van Veen grab was performed using an adaptative sampling grid that accounted for tracer’s dispersion trough time. The samples were washed and dried in laboratory and tagged particles were automatically identified using an automated image analysis procedure based on ultraviolet lighting.

Preliminary results show that sediment transport is dominated by a eastward component,probably related with the energetic events from the SW. Ongoing work relates the tracer’s displacement with ADCP (wave and current) data measured nearby the borrow site during the experiment.

 

The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 – IDL and ECOEXA project (MAR-01.04.02-FEAMP-0016).

 

 

How to cite: Cascalho, J., Taborda, R., Rosa, M., Garel, E., Teixeira, S., Alberto, A., and Drago, T.: Monitoring inner shelf sediment transport using fluorescent sand tracers: an example from the south coast of Portugal , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15834, https://doi.org/10.5194/egusphere-egu21-15834, 2021.

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