Ponències/Comunicacions de congressoshttp://hdl.handle.net/2117/35072024-03-29T07:26:38Z2024-03-29T07:26:38ZHighly-resolved simulations of surf zone hydrodynamics driven by irregular waves using Smoothed Particle HydrodynamicsLowe, Ryan J.Altomare, CorradoBuckley, Mark L.da Silva, RenanHansen, Jeff E.Rijnsdorp, Dirk P.Domínguez Alonso, José ManuelCrespo, Alejandro J.C.http://hdl.handle.net/2117/4002152024-01-24T16:30:30Z2024-01-24T16:23:54ZHighly-resolved simulations of surf zone hydrodynamics driven by irregular waves using Smoothed Particle Hydrodynamics
Lowe, Ryan J.; Altomare, Corrado; Buckley, Mark L.; da Silva, Renan; Hansen, Jeff E.; Rijnsdorp, Dirk P.; Domínguez Alonso, José Manuel; Crespo, Alejandro J.C.
As waves approach the steep slopes of reefs, plunging breaking usually occurs where the free surface overturns and violent water motion is triggered. Resolving such surf zone processes poses significant challenges for conventional mesh-based hydrodynamic models due to the rapidly-deforming nature of the free surface; yet accurate prediction of these hydrodynamics is critical to a wide range of nearshore processes driven by waves (e.g. wave dissipation and energy transfers; mean water levels and currents; and wave runup). In this study we assess the ability of the mesh-free, Lagrangian particle-based numerical approach, Smoothed Particle Hydrodynamics (SPH) using DualSPHysics, to simulate the fine-scale hydrodynamic processes generated by irregular wave transformation over a fringing reef by comparing results against detailed experimental observations. To improve computational efficiency, the DualSPHysics model was coupled to the multi-layer non-hydrostatic wave-flow model SWASH to simulate waves within the deep region offshore of the reef up to the fore reef slope prior to breaking. The model was able to accurately reproduce the full range of hydrodynamic processes observed during the experiment across the reef, resolving the complex free surface deformation during plunging breaking, the spectral evolution of waves across the reef flat (including nonlinear wave shape), the mean water levels and currents, and wave runup at the shoreline. Using the long duration simulations (>400 wave periods), the model was able to reproduce the full range of wave motions over the reef (sea-swell, infragravity, and very low frequencies), including the increasing dominance of low frequency waves towards the shoreline and the large cross-reef standing wave motions excited by the reef geometry.
2024-01-24T16:23:54ZLowe, Ryan J.Altomare, CorradoBuckley, Mark L.da Silva, RenanHansen, Jeff E.Rijnsdorp, Dirk P.Domínguez Alonso, José ManuelCrespo, Alejandro J.C.As waves approach the steep slopes of reefs, plunging breaking usually occurs where the free surface overturns and violent water motion is triggered. Resolving such surf zone processes poses significant challenges for conventional mesh-based hydrodynamic models due to the rapidly-deforming nature of the free surface; yet accurate prediction of these hydrodynamics is critical to a wide range of nearshore processes driven by waves (e.g. wave dissipation and energy transfers; mean water levels and currents; and wave runup). In this study we assess the ability of the mesh-free, Lagrangian particle-based numerical approach, Smoothed Particle Hydrodynamics (SPH) using DualSPHysics, to simulate the fine-scale hydrodynamic processes generated by irregular wave transformation over a fringing reef by comparing results against detailed experimental observations. To improve computational efficiency, the DualSPHysics model was coupled to the multi-layer non-hydrostatic wave-flow model SWASH to simulate waves within the deep region offshore of the reef up to the fore reef slope prior to breaking. The model was able to accurately reproduce the full range of hydrodynamic processes observed during the experiment across the reef, resolving the complex free surface deformation during plunging breaking, the spectral evolution of waves across the reef flat (including nonlinear wave shape), the mean water levels and currents, and wave runup at the shoreline. Using the long duration simulations (>400 wave periods), the model was able to reproduce the full range of wave motions over the reef (sea-swell, infragravity, and very low frequencies), including the increasing dominance of low frequency waves towards the shoreline and the large cross-reef standing wave motions excited by the reef geometry.Improving predictions of nearshore wave dynamics and coastal impacts using Smooth Particle Hydrodynamic modelsLowe, Ryan J.Buckley, Mark L.Altomare, CorradoRijnsdorp, Dirk P.Suzuki, TomohiroBricker, Jeremyhttp://hdl.handle.net/2117/4002142024-01-24T16:30:27Z2024-01-24T16:21:39ZImproving predictions of nearshore wave dynamics and coastal impacts using Smooth Particle Hydrodynamic models
Lowe, Ryan J.; Buckley, Mark L.; Altomare, Corrado; Rijnsdorp, Dirk P.; Suzuki, Tomohiro; Bricker, Jeremy
In this study we assess the capabilities of the mesh-free, Lagrangian particle method (Smooth Particle Hydrodynamics, SPH) method to simulate the detailed hydrodynamic processes generated by both spilling and plunging breaking waves within the surf zone, and present how the approach can be used to predict a broad spectrum of hydrodynamic processes relevant to coastal applications where wave breaking is important. The weakly-compressible SPH code DualSPHysics was applied to simulate wave breaking over two bathymetric profiles (a plane beach and fringing reef) and compared to experimental flume measurements of waves, currents, and mean water levels. We demonstrate how the model can accurately reproduce a broad range of relevant hydrodynamic processes, ranging from the nonlinear evolution of wave shapes across the surfzone, wave setup distributions, mean current profiles and wave runup. We compare the surfzone predictions with results from other classes of wave models, and illustrate some of the advantages of the SPH approach (particularly in resolving the hydrodynamics above the wave trough). Overall, the results reveal how the mesh-free SPH approach can accurately reproduce the detailed wave breaking processes with comparable skill to state-of-the-art mesh-based Computational Fluid Dynamic models, and how it can be used as a valuable tool to develop new physical insight into surf zone processes.
2024-01-24T16:21:39ZLowe, Ryan J.Buckley, Mark L.Altomare, CorradoRijnsdorp, Dirk P.Suzuki, TomohiroBricker, JeremyIn this study we assess the capabilities of the mesh-free, Lagrangian particle method (Smooth Particle Hydrodynamics, SPH) method to simulate the detailed hydrodynamic processes generated by both spilling and plunging breaking waves within the surf zone, and present how the approach can be used to predict a broad spectrum of hydrodynamic processes relevant to coastal applications where wave breaking is important. The weakly-compressible SPH code DualSPHysics was applied to simulate wave breaking over two bathymetric profiles (a plane beach and fringing reef) and compared to experimental flume measurements of waves, currents, and mean water levels. We demonstrate how the model can accurately reproduce a broad range of relevant hydrodynamic processes, ranging from the nonlinear evolution of wave shapes across the surfzone, wave setup distributions, mean current profiles and wave runup. We compare the surfzone predictions with results from other classes of wave models, and illustrate some of the advantages of the SPH approach (particularly in resolving the hydrodynamics above the wave trough). Overall, the results reveal how the mesh-free SPH approach can accurately reproduce the detailed wave breaking processes with comparable skill to state-of-the-art mesh-based Computational Fluid Dynamic models, and how it can be used as a valuable tool to develop new physical insight into surf zone processes.Modelo numérico de la penetración de ondas largas en puertos y bahíasSánchez-Arcilla Conejo, Agustínhttp://hdl.handle.net/2117/3980592023-12-15T08:00:28Z2023-12-15T07:52:00ZModelo numérico de la penetración de ondas largas en puertos y bahías
Sánchez-Arcilla Conejo, Agustín
2023-12-15T07:52:00ZSánchez-Arcilla Conejo, AgustínDevelopments and application of an offline coupling for armor block breakwaters on impermeable bedTagliafierro, BonaventuraAltomare, CorradoSánchez-Arcilla Conejo, AgustínDomínguez Alonso, José ManuelCrespo, Alejandro J.C.Gómez-Gesteira, Monchohttp://hdl.handle.net/2117/3907962023-09-17T05:23:37Z2023-07-13T12:01:00ZDevelopments and application of an offline coupling for armor block breakwaters on impermeable bed
Tagliafierro, Bonaventura; Altomare, Corrado; Sánchez-Arcilla Conejo, Agustín; Domínguez Alonso, José Manuel; Crespo, Alejandro J.C.; Gómez-Gesteira, Moncho
This paper proposes an optimization strategy that can be used in open-source hydrodynamic model to reduce the computational cost of simulations that aim to investigate the structural performance of port and coastal infrastructure under high-return period wave conditions. The strategy we put forward allows for the anticipation of possible scenarios that may trigger breakwater failures such as breakage or block displacement, as well as loss of dissipative capabilities due to changes in their layout. The studied procedure comprises the use of model data and numerical simulations, utilizing numerical tools to address multi-scale phenomena. First, the procedure begins by propagat-ing a particular wave condition to estimate the wave demand at the toe of a breakwater composed of tetrapod units with a high degree of accuracy. Data sampled at different locations nearby the point of interest is then employed to initialize another simulator that uses a much smaller computational domain. A sensitivity analysis is performed to discuss the applicability of the procedure to estimate extreme loads on such structures, and considering the mobile nature of the breakwater blocks. The results show that the proposed series of tools can be used to reduce the computational costs of the overall model simulation, with certain precautions that are highlighted to retain an acceptable level of accuracy.
2023-07-13T12:01:00ZTagliafierro, BonaventuraAltomare, CorradoSánchez-Arcilla Conejo, AgustínDomínguez Alonso, José ManuelCrespo, Alejandro J.C.Gómez-Gesteira, MonchoThis paper proposes an optimization strategy that can be used in open-source hydrodynamic model to reduce the computational cost of simulations that aim to investigate the structural performance of port and coastal infrastructure under high-return period wave conditions. The strategy we put forward allows for the anticipation of possible scenarios that may trigger breakwater failures such as breakage or block displacement, as well as loss of dissipative capabilities due to changes in their layout. The studied procedure comprises the use of model data and numerical simulations, utilizing numerical tools to address multi-scale phenomena. First, the procedure begins by propagat-ing a particular wave condition to estimate the wave demand at the toe of a breakwater composed of tetrapod units with a high degree of accuracy. Data sampled at different locations nearby the point of interest is then employed to initialize another simulator that uses a much smaller computational domain. A sensitivity analysis is performed to discuss the applicability of the procedure to estimate extreme loads on such structures, and considering the mobile nature of the breakwater blocks. The results show that the proposed series of tools can be used to reduce the computational costs of the overall model simulation, with certain precautions that are highlighted to retain an acceptable level of accuracy.An insightful tool for the response of armor block breakwaters on impermeable bed combining numerical modeling techniquesTagliafierro, BonaventuraAltomare, CorradoMitsui, JunDomínguez Alonso, José ManuelCrespo, Alejandro J.C.Gómez Gesteira, MonchoHernaez, MarioSánchez-Arcilla Conejo, Agustínhttp://hdl.handle.net/2117/3907952023-09-17T09:04:06Z2023-07-13T11:57:08ZAn insightful tool for the response of armor block breakwaters on impermeable bed combining numerical modeling techniques
Tagliafierro, Bonaventura; Altomare, Corrado; Mitsui, Jun; Domínguez Alonso, José Manuel; Crespo, Alejandro J.C.; Gómez Gesteira, Moncho; Hernaez, Mario; Sánchez-Arcilla Conejo, Agustín
We aim to increase the efficiency of an open-source hydrodynamic model in investigating the structural performance of port infrastructure under high return period wave conditions, thus anticipating possible scenarios that can trigger breakwater failures intended as breakage or as block displacement and loss of dissipative capabilities due to changes in their layout. A synergic model chain, which comprises the use of data models and numerical simulations, stands at the base of the proposed research that has leveraged the particular suitability of each tool to address the multi-scale nature at which the physics of the interaction between sea waves and port reliability develops. We employ a novel numerical tool, developed within the SPH-based model DualSPHysics, for offline coupling techniques to first estimate with a high degree of accuracy the wave demand at the toe of breakwater composed of tetrapod units, and then we perform a sensitivity analysis to discuss the applicability of the procedure for estimating the extreme loads on coastal structures. The proposed procedure will possibly lead to understanding the pressure field yielded by waves, especially when ultimate limit states are triggered, which in turn can transform into a design tool for structural optimization.
2023-07-13T11:57:08ZTagliafierro, BonaventuraAltomare, CorradoMitsui, JunDomínguez Alonso, José ManuelCrespo, Alejandro J.C.Gómez Gesteira, MonchoHernaez, MarioSánchez-Arcilla Conejo, AgustínWe aim to increase the efficiency of an open-source hydrodynamic model in investigating the structural performance of port infrastructure under high return period wave conditions, thus anticipating possible scenarios that can trigger breakwater failures intended as breakage or as block displacement and loss of dissipative capabilities due to changes in their layout. A synergic model chain, which comprises the use of data models and numerical simulations, stands at the base of the proposed research that has leveraged the particular suitability of each tool to address the multi-scale nature at which the physics of the interaction between sea waves and port reliability develops. We employ a novel numerical tool, developed within the SPH-based model DualSPHysics, for offline coupling techniques to first estimate with a high degree of accuracy the wave demand at the toe of breakwater composed of tetrapod units, and then we perform a sensitivity analysis to discuss the applicability of the procedure for estimating the extreme loads on coastal structures. The proposed procedure will possibly lead to understanding the pressure field yielded by waves, especially when ultimate limit states are triggered, which in turn can transform into a design tool for structural optimization.Simulation of a flexible fish farming net in currents and waves with DualSPHysics: maritime and naval architecture applicationsGonzález Ávalos, RaúlAltomare, CorradoGironella Cobos, XavierCabrera Crespo, AlejandroMartinez Estevez, Ivanhttp://hdl.handle.net/2117/3896752023-06-22T18:50:18Z2023-06-22T18:47:34ZSimulation of a flexible fish farming net in currents and waves with DualSPHysics: maritime and naval architecture applications
González Ávalos, Raúl; Altomare, Corrado; Gironella Cobos, Xavier; Cabrera Crespo, Alejandro; Martinez Estevez, Ivan
In high-energy sea states, the deformation of fish farming nets is a limiting factor in the design, therefore it is necessary to have adequate models of flexible nets. However, the standard industrial modelling software used, do not consider nonlinearities and their implication in the physical interaction with the fluid. The present work focuses on establishing for the first time the applicability and suitability of the Smoothed Particle Hydrodynamics (SPH) method to model fish farm nets. The proposed method allows to discretize the geometry of the net in SPH as a set of nodes and dynamic moorings, allowing the analysis of the deformation of fish farming nets in currents and waves considering non-linear effects, a critical aspect of fluid-structure interaction and the generated structural deformation. A preliminary validation of the proposed method has been performed using DualSPHysics and a modified lumped-mass model, which is based on the use of interconnected mass nodes with dynamic moorings using MoorDyn. The generation of the net is optimized and automated in MATLAB, based on the solidity and distributed mass conservation along the nodes and connections. Results obtained have been compared with a work, which incorporates nonlinear elastic bars coupled to a Computational Fluid Dynamics (CFD) solver.
2023-06-22T18:47:34ZGonzález Ávalos, RaúlAltomare, CorradoGironella Cobos, XavierCabrera Crespo, AlejandroMartinez Estevez, IvanIn high-energy sea states, the deformation of fish farming nets is a limiting factor in the design, therefore it is necessary to have adequate models of flexible nets. However, the standard industrial modelling software used, do not consider nonlinearities and their implication in the physical interaction with the fluid. The present work focuses on establishing for the first time the applicability and suitability of the Smoothed Particle Hydrodynamics (SPH) method to model fish farm nets. The proposed method allows to discretize the geometry of the net in SPH as a set of nodes and dynamic moorings, allowing the analysis of the deformation of fish farming nets in currents and waves considering non-linear effects, a critical aspect of fluid-structure interaction and the generated structural deformation. A preliminary validation of the proposed method has been performed using DualSPHysics and a modified lumped-mass model, which is based on the use of interconnected mass nodes with dynamic moorings using MoorDyn. The generation of the net is optimized and automated in MATLAB, based on the solidity and distributed mass conservation along the nodes and connections. Results obtained have been compared with a work, which incorporates nonlinear elastic bars coupled to a Computational Fluid Dynamics (CFD) solver.SPH simulation of wave breaking over a barred beach and comparison with experimentsScandura, PietroAltomare, CorradoCáceres Rabionet, IvánViccione, GiacomoVan Der A, Dominichttp://hdl.handle.net/2117/3896742023-06-22T18:50:16Z2023-06-22T18:45:30ZSPH simulation of wave breaking over a barred beach and comparison with experiments
Scandura, Pietro; Altomare, Corrado; Cáceres Rabionet, Iván; Viccione, Giacomo; Van Der A, Dominic
This paper presents an SPH numerical simulation of the hydrodynamics due to monochromatic waves breaking on a rigid barred beach profile. The simulation is compared with large–scale laboratory experiments, in which detailed water surface measurements were made at 22 cross-shore locations. The results include wave heights, and the phase-averaged velocity and time-mean velocities along the bar. Overall, the SPH model is able to reproduce several features of this complex flow. Information about the correct setup of an SPH simulation to accurately reproduce the physical processes involved in the wave breaking is also reported. The results show that a recirculating cell, just above the bar through, is generated because of wave breaking. The flow in this cell contributes to the growth of the bar when the bed is made up of mobile material.
2023-06-22T18:45:30ZScandura, PietroAltomare, CorradoCáceres Rabionet, IvánViccione, GiacomoVan Der A, DominicThis paper presents an SPH numerical simulation of the hydrodynamics due to monochromatic waves breaking on a rigid barred beach profile. The simulation is compared with large–scale laboratory experiments, in which detailed water surface measurements were made at 22 cross-shore locations. The results include wave heights, and the phase-averaged velocity and time-mean velocities along the bar. Overall, the SPH model is able to reproduce several features of this complex flow. Information about the correct setup of an SPH simulation to accurately reproduce the physical processes involved in the wave breaking is also reported. The results show that a recirculating cell, just above the bar through, is generated because of wave breaking. The flow in this cell contributes to the growth of the bar when the bed is made up of mobile material.Restoring and rehabilitation of historical coastal asset with SPHAltomare, CorradoGironella Cobos, XavierCabrera Crespo, AlejandroDomínguez Alonso, José ManuelTafuni, AngelantonioMuñoz-Ramos, Gregorihttp://hdl.handle.net/2117/3896732023-06-22T18:50:13Z2023-06-22T18:43:26ZRestoring and rehabilitation of historical coastal asset with SPH
Altomare, Corrado; Gironella Cobos, Xavier; Cabrera Crespo, Alejandro; Domínguez Alonso, José Manuel; Tafuni, Angelantonio; Muñoz-Ramos, Gregori
On January 20th, 2020, the storm Gloria caused the failure of the seaward platform and part of the footbridge of the Pont del Petroli pier at the beach of Badalona (Spain). A beam of about 15 m fell into the sea due to strong impacts caused by a long-lasting wave action. SPH modelling the wave-structure interaction provoked by the storm Gloria is here carried out. For its own meshless scheme and Lagrangian nature, SPH is ideal to model violent wave-structure interaction, characterized by heavy wave breaking, large discontinuity along the free surface and overtopping waves. The WCSPH-based DualSPHysics code has been employed for the scope. 2D and 3D modelling have been performed. The former one helped to understand whether a change in the foreshore profile and local water depth might affect the wave transformation and consequent wave-structure-interaction. The latter one was employed to offer a preliminary insight into the response of a propose restoration design alternatives. Both 2D and 3D modelling have been carried out with detailed representation of the structural elements (resolution about 1/10 of the platform and footbridge width) and reasonable computational time thanks to GPU computing.
2023-06-22T18:43:26ZAltomare, CorradoGironella Cobos, XavierCabrera Crespo, AlejandroDomínguez Alonso, José ManuelTafuni, AngelantonioMuñoz-Ramos, GregoriOn January 20th, 2020, the storm Gloria caused the failure of the seaward platform and part of the footbridge of the Pont del Petroli pier at the beach of Badalona (Spain). A beam of about 15 m fell into the sea due to strong impacts caused by a long-lasting wave action. SPH modelling the wave-structure interaction provoked by the storm Gloria is here carried out. For its own meshless scheme and Lagrangian nature, SPH is ideal to model violent wave-structure interaction, characterized by heavy wave breaking, large discontinuity along the free surface and overtopping waves. The WCSPH-based DualSPHysics code has been employed for the scope. 2D and 3D modelling have been performed. The former one helped to understand whether a change in the foreshore profile and local water depth might affect the wave transformation and consequent wave-structure-interaction. The latter one was employed to offer a preliminary insight into the response of a propose restoration design alternatives. Both 2D and 3D modelling have been carried out with detailed representation of the structural elements (resolution about 1/10 of the platform and footbridge width) and reasonable computational time thanks to GPU computing.Measurements and modeling of sediment transport during offshore and onshore bar migrationGrossmann, FlorianHurther, DavidSánchez-Arcilla Conejo, AgustínAlsina Torrent, José Maríahttp://hdl.handle.net/2117/3858032023-10-15T00:30:44Z2023-03-30T12:38:24ZMeasurements and modeling of sediment transport during offshore and onshore bar migration
Grossmann, Florian; Hurther, David; Sánchez-Arcilla Conejo, Agustín; Alsina Torrent, José María
Effective design of interventions in the coastal zone (flood defense, nourishments, etc.) requires understanding of long term coastal evolution. Historically, such evolution has been difficult to model because of different processes in storms and calm conditions, and the specific calibration factors required. This knowledge gap partly resulted from difficulties in measuring bedload and accretive transport processes at high detail. In the present study such measurements were obtained in the shoaling and outer surf zone of large-scale wave flume experiments with offshore-/onshore-migrating breaker bars. Physical insight from the measurements guided model decisions in a practical modeling approach separating bedload and suspended load but using the same calibration for storm and calm conditions. As a result, good replication (most tests within factor 2) of measured transport rates is obtained on the basis of free stream velocities. Identified priorities for development include parametrization of hydraulic roughness and wave breaking’s influences on entrainment and suspension.
2023-03-30T12:38:24ZGrossmann, FlorianHurther, DavidSánchez-Arcilla Conejo, AgustínAlsina Torrent, José MaríaEffective design of interventions in the coastal zone (flood defense, nourishments, etc.) requires understanding of long term coastal evolution. Historically, such evolution has been difficult to model because of different processes in storms and calm conditions, and the specific calibration factors required. This knowledge gap partly resulted from difficulties in measuring bedload and accretive transport processes at high detail. In the present study such measurements were obtained in the shoaling and outer surf zone of large-scale wave flume experiments with offshore-/onshore-migrating breaker bars. Physical insight from the measurements guided model decisions in a practical modeling approach separating bedload and suspended load but using the same calibration for storm and calm conditions. As a result, good replication (most tests within factor 2) of measured transport rates is obtained on the basis of free stream velocities. Identified priorities for development include parametrization of hydraulic roughness and wave breaking’s influences on entrainment and suspension.Posidonia beach-cast and banquette: evaluation of sediment trapping and characterisation for coastal protectionAstudillo Gutiérrez, Carlos SalvadorGracia Garcia, VicenteSierra Pedrico, Juan PabloCáceres Rabionet, IvánSánchez-Arcilla Conejo, Agustínhttp://hdl.handle.net/2117/3858002023-11-12T04:05:25Z2023-03-30T12:31:49ZPosidonia beach-cast and banquette: evaluation of sediment trapping and characterisation for coastal protection
Astudillo Gutiérrez, Carlos Salvador; Gracia Garcia, Vicente; Sierra Pedrico, Juan Pablo; Cáceres Rabionet, Iván; Sánchez-Arcilla Conejo, Agustín
The accumulation of Posidonia meadow remains is a recurrent phenomenon along the Catalan coast. As we move along the coastline from Barcelona towards the south, during autumn and winter the remains of Posidonia Oceanica gradually appear in areas close to the shoreline and the most sheltered areas of the beach. From the municipality of Salou (122 km south of Barcelona) to Deltebre, more than half of the beaches have the presence of banquettes with heights ranging from 20 cm up to 120 cm. This work proposes a new study of Posidonia accumulations on the southern coast of Catalonia, presenting a new laboratory methodology for the quantification of sediments retained on the Posidonia banquettes. This methodology eliminates the organic part of each sieve, muffling the sample at 500ºC for 30 minutes. In this way, the weight of sand per volume of sampled banquettes can be quantified. The results show a sediment retention value of at least 70% of the total weight of the sample, with a distribution equal to or finer than beach sand. It is also observed that a beach bench that is in the process of accumulating at the shoreline tends to accumulate less sediment than one that is in a position above the shoreline.
2023-03-30T12:31:49ZAstudillo Gutiérrez, Carlos SalvadorGracia Garcia, VicenteSierra Pedrico, Juan PabloCáceres Rabionet, IvánSánchez-Arcilla Conejo, AgustínThe accumulation of Posidonia meadow remains is a recurrent phenomenon along the Catalan coast. As we move along the coastline from Barcelona towards the south, during autumn and winter the remains of Posidonia Oceanica gradually appear in areas close to the shoreline and the most sheltered areas of the beach. From the municipality of Salou (122 km south of Barcelona) to Deltebre, more than half of the beaches have the presence of banquettes with heights ranging from 20 cm up to 120 cm. This work proposes a new study of Posidonia accumulations on the southern coast of Catalonia, presenting a new laboratory methodology for the quantification of sediments retained on the Posidonia banquettes. This methodology eliminates the organic part of each sieve, muffling the sample at 500ºC for 30 minutes. In this way, the weight of sand per volume of sampled banquettes can be quantified. The results show a sediment retention value of at least 70% of the total weight of the sample, with a distribution equal to or finer than beach sand. It is also observed that a beach bench that is in the process of accumulating at the shoreline tends to accumulate less sediment than one that is in a position above the shoreline.