Representing Small Shallow Water Estuary Hydrodynamics to Uncover Litter Transport Patterns

Ahnouch, Lubna  Benchama; Buschman, Frans; Boisgontier, Helene; Bio, Ana; Vieira, Luis R.; Antunes, Sara C.; Kett, Gary F.; Sousa-Pinto, Isabel; Iglesias, Isabel

doi:10.3390/w17182698

This is an early access version, the complete PDF, HTML, and XML versions will be available soon.

Open AccessArticle

Representing Small Shallow Water Estuary Hydrodynamics to Uncover Litter Transport Patterns

by

Lubna Benchama Ahnouch

¹,

Frans Buschman

²,

Helene Boisgontier

²,

Ana Bio

³

,

Luis R. Vieira

³

,

Sara C. Antunes

^3,4

,

Gary F. Kett

³

,

Isabel Sousa-Pinto

^3,4

and

Isabel Iglesias

^3,*

¹

Institut Supérieur Industriel de Bruxelles, Haute Ecole Bruxelles-Brabant (ISIB, HE2B), Bd Louis Schmidt 2, 1040, Brussels, Belgium

²

Deltares, Boussinesqweg 1, 2629 HV Delft, The Netherlands

³

Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal

⁴

Departamento de Biologia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal

^*

Author to whom correspondence should be addressed.

Water 2025, 17(18), 2698; https://doi.org/10.3390/w17182698

Submission received: 9 July 2025 / Revised: 31 August 2025 / Accepted: 5 September 2025 / Published: 12 September 2025

(This article belongs to the Special Issue Marine Plastic Pollution: Recent Advances and Future Challenges)

Download Review Reports Versions Notes

Abstract

Plastic pollution is an increasing global concern, with estuaries being especially vulnerable as transition zones between freshwater and marine systems. These ecosystems often accumulate large amounts of waste, affecting wildlife and water quality. This study focuses on analysing the circulation patterns of the Ave Estuary, a small, shallow system on Portugal’s north-western coast, and their influence on litter transport and distribution. This site was selected for installing an aquatic litter removal technology under the EU-funded MAELSTROM project. A 2DH hydrodynamic model using Delft3D FM, coupled with the Wflow hydrological model, was implemented and validated. Various scenarios were simulated to assess estuarine dynamics and pinpoint zones prone to litter accumulation and flood risk. The results show that tidal action and river discharge mainly drive the estuary’s behaviour. Under low discharge, floating litter should be mostly transported toward the ocean, while high discharge conditions should result in litter movement at all depths due to stronger currents. High water levels and flooding occur mainly upstream and in specific low-lying areas near the mouth. Low-velocity zones, which can favour litter accumulation, were found around the main channel and on the western margin near the estuary’s mouth, even during high flows. These findings highlight persistent accumulation zones, even under extreme event conditions.

Keywords: estuarine dynamics; hydrological and hydrodynamic modelling; flood risk; marine litter; marine litter removal technology; Ave Estuary

Share and Cite

MDPI and ACS Style

Ahnouch, L.B.; Buschman, F.; Boisgontier, H.; Bio, A.; Vieira, L.R.; Antunes, S.C.; Kett, G.F.; Sousa-Pinto, I.; Iglesias, I. Representing Small Shallow Water Estuary Hydrodynamics to Uncover Litter Transport Patterns. Water 2025, 17, 2698. https://doi.org/10.3390/w17182698

AMA Style

Ahnouch LB, Buschman F, Boisgontier H, Bio A, Vieira LR, Antunes SC, Kett GF, Sousa-Pinto I, Iglesias I. Representing Small Shallow Water Estuary Hydrodynamics to Uncover Litter Transport Patterns. Water. 2025; 17(18):2698. https://doi.org/10.3390/w17182698

Chicago/Turabian Style

Ahnouch, Lubna Benchama, Frans Buschman, Helene Boisgontier, Ana Bio, Luis R. Vieira, Sara C. Antunes, Gary F. Kett, Isabel Sousa-Pinto, and Isabel Iglesias. 2025. "Representing Small Shallow Water Estuary Hydrodynamics to Uncover Litter Transport Patterns" Water 17, no. 18: 2698. https://doi.org/10.3390/w17182698

APA Style

Ahnouch, L. B., Buschman, F., Boisgontier, H., Bio, A., Vieira, L. R., Antunes, S. C., Kett, G. F., Sousa-Pinto, I., & Iglesias, I. (2025). Representing Small Shallow Water Estuary Hydrodynamics to Uncover Litter Transport Patterns. Water, 17(18), 2698. https://doi.org/10.3390/w17182698

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Menu

Representing Small Shallow Water Estuary Hydrodynamics to Uncover Litter Transport Patterns

Abstract

Share and Cite

Article Metrics

Article Access Statistics

Further Information

Guidelines

MDPI Initiatives

Follow MDPI