Coastal ECO Research projects

En aquest Research Café es presenten projectes on la tecnologia es posa al servei dels mars i els oceans, i que estan lligats amb els objectius ODS Vida Submarina i Acció pel clima.Objectius de Desenvolupament Sostenible::13 - Acció per al ClimaObjectius de Desenvolupament Sostenible::14 - Vida Submarin

The southern lobe of the Llobregat delta: a natural system controlled by human activity

La evolución reciente del hemidelta Sur del Llobregat (Barcelona) es un claro ejemplo de sistema natural dominado por la acción del hombre. Las necesidades de ocupación de la llanura y frente deltaico junto con la regulación del caudal del río han generado un fuerte desequilibrio sedimentario. El ascenso del nivel del mar a largo plazo inducido por el calentamiento global no hará más que agravar esta situación. El artículo presenta las disfunciones generadas y la difícil coexistencia entre la geomorfología y la actividad humana en 4 puntos representativos de la costa objeto de la visita de campo organizada en el marco de las “Xª Jornadas de Geomorfología Litoral”. En la primera parada, al sur de la unidad se observa el impacto causado por el puerto deportivo de Port Ginesta, responsable del cierre del sistema en términos sedimentarios. La segunda parada, en la zona central, es un ejemplo de evolución costera inducida por la acción del oleaje y la orientación de la costa. En la parada 3 se describen los trabajos de restauración de un sistema dunar. Finalmente, al norte de la unidad se observan los efectos de la divergencia en el transporte longitudinal generados por la ampliación del puerto de Barcelona.Postprint (published version

The land–sea coastal border: a quantitative definition by considering the wind and wave conditions in a wave-dominated, micro-tidal environment

A quantitative definition for the land–sea (coastal) transitional area is proposed here for wave-driven areas, based on the variability and isotropy of met-ocean processes. Wind velocity and significant wave height fields are examined for geostatistical anisotropy along four cross-shore transects on the Catalan coast (north-western Mediterranean), illustrating a case of significant changes along the shelf. The variation in the geostatistical anisotropy as a function of distance from the coast and water depth has been analysed through heat maps and scatter plots. The results show how the anisotropy of wind velocity and significant wave height decrease towards the offshore region, suggesting an objective definition for the coastal fringe width. The more viable estimator turns out to be the distance at which the significant wave height anisotropy is equal to the 90th percentile of variance in the anisotropies within a 100 km distance from the coast. Such a definition, when applied to the Spanish Mediterranean coast, determines a fringe width of 2–4 km. Regarding the probabilistic characterization, the inverse of wind velocity anisotropy can be fitted to a log-normal distribution function, while the significant wave height anisotropy can be fitted to a log-logistic distribution function. The joint probability structure of the two anisotropies can be best described by a Gaussian copula, where the dependence parameter denotes a mild to moderate dependence between both anisotropies, reflecting a certain decoupling between wind velocity and significant wave height near the coast. This wind–wave dependence remains stronger in the central baylike part of the study area, where the wave field is being more actively generated by the overlaying wind. Such a pattern controls the spatial variation in the coastal fringe width.Peer ReviewedPostprint (published version

Managing coastal environments under climate change: pathways to adaptation

This paper deals with the question of how to manage vulnerable coastal systems so as to make them sustainable under present and future climates. This is interpreted in terms of the coastal functionality, mainly natural services and support for socio-economic activities. From here we discuss how to adapt for long term trends and for short terms episodic events using the DPSIR framework. The analysis is presented for coastal archetypes from Spain, Ireland and Romania, sweeping a range of meteo-oceanographic and socio-economic pressures, resulting in a wide range of fluxes among them those related to sediment. The analysis emphasizes the variables that provide a higher level of robustness. That means mean sea level for physical factors and population density for human factors. For each of the studied cases high and low sustainability practices, based on stakeholders preferences, are considered and discussed. This allows proposing alternatives and carrying out an integrated assessment in the last section of the paper. This assessment permits building a sequence of interventions called adaptation pathway that enhances the natural resilience of the studied coastal systems and therefore increases their sustainability under present and future conditions.Peer ReviewedPostprint (author's final draft

Sediment transport and dispersal in the nearshore of “flash-flood” rivers

River sediment dispersal on the near-shore of “flash-flood” rivers is investigated using a coupled wave-current-sediment transport model. Besòs and Llobregat rivers (short and mountainous rivers in NW Mediterranean Sea, near to Barcelona City) are used as examples to study the sediment transport under “flash-flood” regime. The modeling system COWAST which includes the coupling between the water circulation model ROMS and the wave model SWAN, is applied to assess the sediment dispersal mechanisms and deposition in the coastal area off the two river mouths. Preferential depositional areas such as mud-belts were identified from the simulations. The sediment dispersal pattern obtained by the model agrees with observational measurments. Complementary numerical simulations revealed sorting of sediment grain size in the cross-shelf direction.Peer ReviewedPostprint (published version

Current treatment of oral candidiasis: a literature review

Candidiasis or oral candidosis is one of the most common human opportunistic fungal infections of the oral cavity. This pathology has a wide variety of treatment which has been studied until these days. The present study offers a literature review on the treatment of oral candidiasis, with the purpose of establish which treatment is the most suitable in each case. Searching the 24 latest articles about treatment of candidiasis it concluded that the incidence depends on the type of the candidiasis and the virulence of the infection. Although nystatin and amphotericin b were the most drugs used locally, fluconazole oral suspension is proving to be a very effective drug in the treatment of oral candidiasis. Fluconazole was found to be the drug of choice as a systemic treatment of oral candidiasis. Due to its good antifungal properties, its high acceptance of the patient and its efficacy compared with other antifungal drugs. But this drug is not always effective, so we need to evaluate and distinguish others like itraconazole or ketoconazole, in that cases when Candida strains resist to fluconazole

Multivariate statistical modelling of future marine storms

Extreme events, such as wave-storms, need to be characterized for coastal infrastructure design purposes. Such description should contain information on both the univariate behaviour and the joint-dependence of storm-variables. These two aspects have been here addressed through generalized Pareto distributions and hierarchical Archimedean copulas. A non-stationary model has been used to highlight the relationship between these extreme events and non-stationary climate. It has been applied to a Representative Concentration Pathway 8.5 Climate-Change scenario, for a fetch-limited environment (Catalan Coast). In the non-stationary model, all considered variables decrease in time, except for storm-duration at the northern part of the Catalan Coast. The joint distribution of storm variables presents cyclical fluctuations, with a stronger influence of climate dynamics than of climate itself.Peer ReviewedPostprint (author's final draft

A multivariate statistical model of extreme events: an application to the Catalan coast

Wave extreme events can be understood as the combination of Storm-intensity, Directionality and Intra-time distribution. However, the dependence structure among these factors is still unclear. A methodology has been developed to model wave-storms whose components are linked together. The model is composed by three parts: an intensity module, a wave directionality module, and an intra-time distribution module. In the Storm-intensity sub-model, generalized Pareto distributions and hierarchical Archimedean copulas have been used to characterize the storm energy, unitary energy, peak wave-period and duration. In the Directionality and Intra-time sub-models, the wave direction (at the peak of the storm) and the storm growth–decay rates are linked to the variables from the intensity model, respectively. The model is applied to the Catalan coast (NW Mediterranean). The outcomes denote spatial patterns that coincide with the state of knowledge. The proposed methodology is able to provide boundary conditions for wave and near-shore studies, saving computational time and establishing the dependence of the proposed variables. Such synthetic storms reproduce the inter-variable co-dependence of the original data.Peer ReviewedPostprint (published version

Green measures for Mediterranean harbours under a changing climate

Harbour operability may be hampered by climate change. Green solutions can be used to provide extra flexibility with respect to present grey infrastructure to adapt to, and mitigate, such functional disruptions with affordable costs. This paper assesses the performance of a green solution (a seagrass meadow) by assessing its effectiveness through numerical modelling. The analysis is carried out at two harbours that, under the present climate, are prone to wave agitation and overtopping problems. The efficiencies of different seagrass layouts are tested at both sites, by comparing the relevant hydrodynamic parameters. It is concluded that, for moderate sea level rise (SLR) rates, illustrated by the central trend of a medium scenario from the Intergovernmental Panel on Climate Change, the use of seagrass meadows would be effective enough to attenuate the impact of SLR on breakwater overtopping. In addition, the use of such measures could attenuate the increases in port agitation due to changes in wave direction caused by climate change. Nevertheless, the complexity of the interactions between hydrodynamics and seagrass would require periodic monitoring and re-evaluation to maintain acceptable risk levels, especially in case of extreme scenarios.Peer ReviewedPostprint (author's final draft

Assessment of green measures as coastal defences using numerical models

Climate change may reduce the performance and design life of “grey” coastal engineering interventions. Green solutions can be combined with present infrastructures providing extra flexibility to adapt our present beaches with affordable costs. This paper assesses the behaviour of a typology of green solutions (seagrass meadows) via numerical hydro-morphodynamic modelling for an erosive beach prone to episodic flooding, under typical Mediterranean conditions. A multivariate method for jointly assessing flooding and erosion via copulas is proposed and developed. In the considered pilot site, different layouts have been tested by analysing their efficiency and limits. It is concluded that, for moderate SLR rates (RCP 4.5. central trend), these green measures could attenuate efficiently the expected changes in marine drivers. However, the complexity of eco-hydraulic interactions on which the Nature Based Solutions depend would demand periodic monitoring and evaluation for maintaining acceptable risk levels, especially in the case of high-end scenarios.Postprint (published version