Assessing the effects of Tidal Energy Converter array size on hydrodynamics of Ria Formosa (Portugal)

info:eu-repo/semantics/publishedVersio

Erasmus experience between the University of Cadiz (Spain) and the University of Algarve (Portugal)

A mobility program was carried out during the last two years between the Universities of Cadiz (Spain) and Algarve (Portugal) under the EU funded Erasmus+ Mobility for Teaching. The objective of the mobility was twofold: on one hand, it included the strengthening of the existing scientific cooperation between the University of Cadiz (home institution) and the University of Algarve (host institution) in the field of the Gulf of Cadiz Physical Oceanography; on the other hand, it pretended to improve the teaching quality, focusing on both the lecturers and the students. Both institutions have long ties of cooperation that have recently been intensified under the umbrella of the International Campus of Marine Excellence (CeiMar). Specific objectives oriented towards the lecturers included the exchange of teaching experiences among them as well as the comparison of teaching strategies and methodologies between the host and home institutions at the Master level in order to evaluate and enhance the best teaching practices with the aim of improving the students learning process. Specific objectives oriented towards the students included: (1) to provide local students that cannot afford studying a Master degree abroad with a foreign teacher in the discipline that will offer them different added expectations; (2) to teach students different subjects from those taught at the host institution, thus benefitting from new scientific knowledge and experiences. It must be pointed out that the subject taught by the home institution lecturer represents a competence lacking at the host institution, hence complementing the program of the discipline and providing an added value to the Master degree. Informal questionnaires carried out among students by the host institution revealed that they evaluated having a foreign teacher as a very positive experience. In terms of research, collaboration among both institutions is of great importance because they are both located within the same geographic region and hence, they share common interests. The mobility promoted finishing on-going collaborative publications as well as sharing new research experiences, data and knowledge, hence leading to an improvement of the Physical Oceanography state-of-the-art in the Gulf of Cadiz. In fact, two scientific papers on the Gulf of Cadiz circulation system and two on the storm climate along the Gulf of Cadiz and its relation with coastal hazards have been recently published as a direct result of the mobility program.info:eu-repo/semantics/publishedVersio

Deployment characterization of a floatable tidal energy converter on a tidal channel, Ria Formosa, Portugal

This paper presents the results of a pilot experiment with an existing tidal energy converter (TEC), Evopod 1 kW floatable prototype, in a real test case scenario (Faro Channel, Ria Formosa, Portugal). A baseline marine geophysical, hydrodynamic and ecological study based on the experience collected on the test site is presented. The collected data was used to validate a hydro-morphodynamic model, allowing the selection of the installation area based on both operational and environmental constraints. Operational results related to the description of power generation capacity, energy capture area and proportion of energy flux are presented and discussed, including the failures occurring during the experimental setup. The data is now available to the scientific community and to TEC industry developers, enhancing the operational knowledge of TEC technology concerning efficiency, environmental effects, and interactions (i.e. device/environment). The results can be used by developers on the licensing process, on overcoming the commercial deployment barriers, on offering extra assurance and confidence to investors, who traditionally have seen environmental concerns as a barrier, and on providing the foundations whereupon similar deployment areas can be considered around the world for marine tidal energy extraction.Acknowledgements The paper is a contribution to the SCORE project, funded by the Portuguese Foundation for Science and Technology (FCT e PTDC/ AAG-TEC/1710/2014). Andre Pacheco was supported by the Portu- guese Foundation for Science and Technology under the Portuguese Researchers' Programme 2014 entitled “Exploring new concepts for extracting energy from tides” (IF/00286/2014/CP1234). Eduardo GGorbena has received funding for the OpTiCA project from the ~ Marie Skłodowska-Curie Actions of the European Union's H2020- MSCA-IF-EF-RI-2016/under REA grant agreement n [748747]. The authors would like to thank to the Portuguese Maritime Authorities and Sofareia SA for their help on the deployment.info:eu-repo/semantics/publishedVersio

Use of a Bayesian Network for coastal hazards, impact and disaster risk reduction assessment at a coastal barrier (Ria Formosa, Portugal)

Coastal communities are threatened by the impact of severe storms that may cause significant loss or damage of property and life. The main processes causing such impacts at sandy coastlines and nearby coastal communities are storm erosion, overwash and inundation. Coastal response under present conditions and under predicted climate change has been frequently assessed on the basis of numerical models, which in turn can be also used to evaluate the effectiveness of Disaster Risk Reduction (DRR) measures to mitigate the response of the coast to the imposed conditions. However, detailed morphodynamic models are computationally expensive and not commonly used by coastal managers. The present work proposes the construction of a probabilistic Bayesian Network (BN) as a surrogate for the numerical simulations. This BN is trained with a large number of morphodynamic simulations, under a variety of storm conditions and DRR measures, in order to serve as a front-end platform for visualising, analysing and evaluating combined results of the numerical modelling. The BN introduced in an early warning system will be able to serve both, as a predictive and as a working tool to determine impacts and evaluate risk reduction after measures implementation. Here, an example of the implementation and results of such a BN system is presented. The BN system was built for a coastal sector of the Ria Formosa barrier island system (South Portugal) to inform the degree of impact derived from overwash and erosion over the study area. The BN boundary conditions include variable wave height, water level, and wave period. The impact on receptors, including houses and infrastructure, was assessed. In addition, this tool can inform about the effectiveness of a particular DRR measure. The evaluated DRR measures were two primary measures (partial house removal and beach replenishment) and a non-primary measure (improve channels of communication), all measures proposed by local stakeholders. Results show that for a storm with wave characteristics of the 1 in 50 year return period and spring tide conditions, the house removal DRR reduces the overwash impact by 15% and erosion impact by 58%. The implementation of beach replenishment could reduce the erosion impact of the same event by 96% while it would have a smaller effect on the overwash impact (16%). The implementation of non-primary measures would have a much smaller effect on risk reduction. The combined effect of the above DRR measures (mainly house removal and beach nourishment) reduces storm impacts at the study area to a value near zero. The BN surrogates the model simulated onshore hazards and translates them into impacts for the current conditions, which give a high degree of confidence in the potential application of the BN as a management tool

Modeling of Coastal Erosion in Exposed and Groin-Protected Steep Beaches

Process-based models are suitable tools for reproducing storm-driven erosion. However, their performance has been mainly examined on mild-slope sandy beaches and their use on steep beaches still represents a challenge. Here, open-source process-based model XBeach experiments were combined with topographical measurements collected for two storms (16- and 5-year return period) to obtain a reliable model. The model parameters "facua"(parameterized wave asymmetry and skewness sediment transport component), "bermslope"(upslope transport term for semireflective beaches), and "wetslope"(critical avalanching submerged slope) were utilized for calibration and validation. The 16-year storm simulations on an exposed beach revealed that whether bermslope increased and "facua"must be reduced, and vice versa, to properly simulate erosion. Adding bermslope provided excellent results for these storms when using facua and wetslope values close to the recommended values. In a groin-protected site, XBeach was successfully calibrated and validated for the tested storms using these parameters, although with different values. These experiments demonstrated that the appropriate use of these parameters can satisfactorily simulate morphological changes on steep beaches for different hydrodynamic conditions and coastal settings (exposed and groin protected). © 2022 This work is made available under the terms of the Creative Commons Attribution 4.0 International license

Effectiveness assessment of risk reduction measures at coastal areas using a decision support system: Findings from Emma storm

Storms impact coastal areas often causing damages and losses at occupied areas. On a scenario of increasing human occupation at coastal zones and under climate change conditions (including sea level rise and increasing frequency of extreme sea levels), the consequences of storms arc expected to be amplified if no adaptation or further management actions are implemented. The selection of the best possible coastal management measures, considering both costs and effectiveness, will be mandatory in the future, in order to optimise resources. This work analyses the performance of risk reduction measures (beach nourishment and receptors - house and infrastructures - removal), using a decision support system comprised by a morphodynamic numerical model (XBeach) and a Bayesian network based on the source-pathway-receptor concept. The effectiveness of the risk reduction measures is then assessed by a simple index expressing the consequences to the receptors. The approach was tested at Faro Beach by evaluating its performance for a particular storm, Emma (Feb/March 2018), which fiercely impacted the southern coast of Portugal. The output results from the modelling were compared to field observations of the actual damages caused by the storm. The combined use of both measures or the solely use of the nourishment would avoid almost all observed impacts from this storm. The work is pioneer on demonstrating the use of a decision support system for coastal regions validated against observed impacts for a high-energy storm event. The methodology and the proposed index arc adaptable to any sandy coastal region and can be used to test (and improve) management options at a broad number of coastal areas worldwide, minimizing implementation costs and reducing the risk to the occupation and to the people. (C) 2018 Elsevier B.V. All rights reserved.FCT Investigator program [IF/01047/2014]European Union 7th Framework ProgrammeEuropean Union (EU) [603458]project EVREST [PTDC/MAR-EST/1031/2014]project EW-COAST [G-LISBOA-01-145-FEDER-028657]Portuguese Science and Technology Foundation (FCT)Portuguese Foundation for Science and Technology [UID/MAR/00350/2013]research group RNM-328 of the Andalusian Research Plan (PAI)info:eu-repo/semantics/publishedVersio

Uncertainty Analysis Related to Beach Morphology and Storm Duration for More Reliable Early Warning Systems for Coastal Hazards

Early warning systems (EWSs) for coastal erosion are cost-effective instruments for risk reduction. Among other aspects, the selection of the pre-storm beach morphology and the definition of storm characteristics can affect EWS reliability. Here, XBeach simulations were used to assess the uncertainties in beach-dune erosion related to the variability of storm severity and duration and pre-storm morphology. Wave height return periods (from 5 to 50 years) determined the severity and the duration variability was established from confidence intervals after an adjustment with wave height. The variability of steep profiles included different berm morphologies (from fully developed to eroded berms). Three indicators, relative eroded volume, proportional berm retreat and proportional dune retreat, were evaluated. The experiments revealed that: (a) Relative eroded volume uncertainties related to the pre-storm morphology variability were slightly lower (maximum 8%) than the uncertainties related to storm duration (11%–18%). (b) Pre-storm profile variability can induce large uncertainties in the proportional berm retreat (up to 88%) for moderate events such as the 5- and 10-year events. Storm duration variability had less influence on this indicator (maximum 12%). (c) The uncertainties in the proportional dune retreat increased with storm severity and they ranged between 14% and 41% for pre-storm profile variability and between 2% and 40% for storm duration variability. Duration variability even governed the occurrence of dune breaching on eroded berm profiles in the most extreme event. Hence, the uncertainties related to initial/forcing conditions, namely pre-storm morphology and storm duration, must be assessed to develop reliable coastal erosion EWSs

Process-based indicators to assess storm induced coastal hazards

Storms are responsible for several hazards (e.g. overwash, erosion, inundation) in coastal areas, leading to the destruction of property and loss of life in populated areas. Various indicators are used to express potential storm impact and describe the associated hazards. The most commonly used indicators include either forcing parameters (e.g. wave height, sea level) or coastal morphologies (e.g. dune height or berm width). Whereas they do not represent the processes associated with storm induced hazards in coastal areas. Alternatively, a hazard could be better characterised if process-based indicators are used instead. Process-based indicators express the result of the forcing mechanisms acting over the coastal morphology and reflect both hydrodynamic and morphological characteristics. This work discusses and synthesizes the most relevant process-based indicators for sandy shores subject to overwash, erosion and inundation promoted by storms. Those include: overwash depth, potential and extent; shoreline, berm or dune retreat; vertical erosion; and inundation depth and extent. The selection of a reduced set of process-based indicators to identify coastal hazards induced by storms in sandy coasts will facilitate comparison of different coastal behaviours for distinct storm return periods, and help to optimise coastal management plans, thereby contributing to the reduction of coastal risks.info:eu-repo/semantics/publishedVersio

Modeling of coastal erosion in exposed and groin-protected steep beaches

Process-based models are suitable tools for reproducing storm-driven erosion. However, their performance has been mainly examined on mild-slope sandy beaches and their use on steep beaches still represents a challenge. Here, open-source process-based model XBeach experiments were combined with topographical measurements collected for two storms (16- and 5-year return period) to obtain a reliable model. The model parameters “facua” (parameterized wave asymmetry and skewness sediment transport component), “bermslope” (upslope transport term for semireflective beaches), and “wetslope” (critical avalanching submerged slope) were utilized for calibration and validation. The 16-year storm simulations on an exposed beach revealed that whether bermslope increased and “facua” must be reduced, and vice versa, to properly simulate erosion. Adding bermslope provided excellent results for these storms when using facua and wetslope values close to the recommended values. In a groin-protected site, XBeach was successfully calibrated and validated for the tested storms using these parameters, although with different values. These experiments demonstrated that the appropriate use of these parameters can satisfactorily simulate morphological changes on steep beaches for different hydrodynamic conditions and coastal settings (exposed and groin protected).info:eu-repo/semantics/acceptedVersio

Development of tutorials to promote self-directed programming learning: application to postgraduate studies

Most students graduated in Marine Science or other related disciplines (e.g. Geology, Biology, Chemistry) lack the basic background knowledge in scientific programming and modelling (e.g. Matlab, Fortran, Python), necessary in numerical disciplines such as Physical or Coastal Oceanography. Hence, when they enroll for postgraduate studies in Oceanography they are not able to properly follow the lessons related to the above disciplines and generally become discouraged. Trying to meet the needs of those students during the lessons would result in not accomplishing the course’s program, given the fact that MSc programs have concentrated material and are extremely demanding for the students. For this reason, a collaborative effort has been made among various lecturers to develop tutorials in order to promote self-directed learning among the MSc students with the aim of alleviating those deficiencies. These tutorials were applied in two different courses and consisted in: i) a quick-start Matlab guide for NetCDF meteorological and oceanographic data handling and plotting, and ii) the use of a front-end platform for visualising, analysing and evaluating results from the state-of-the-art morphodynamic model XBEACH-G. The above methods helped the students to understand the potential of programming and numerical modelling, as well as, the importance of applying such approaches both in consulting and research-based carriers. Overall, this methodology resulted in a higher level of satisfaction among students because it offered an active, flexible and self reliant learning method that was adapted to each person’s learning pace and difficulties. Finally, the tutorials proved to be an inclusive teaching strategy able to address the needs of students with different backgrounds, learning styles, and abilities, hence providing a more efficient learning environment, in which all students could reach their potential at their own pace and feel equally valued at the end of the course