Óscar Ferreira

University of Algarve | UALG · Departamento de Ciências da Terra, do Mar e do Ambiente

Blowouts are wind-formed depressions that help maintain the sediment budget and enhance biodiversity in coastal dunes. However, the drivers controlling their evolution and the temporal scales associated to their genesis, development and decay phases remain unclear. To address this, the morphometric characteristics of a series of blowouts on the Anc...

The opening of the Cacela Inlet (southern Portugal) in 2010 led to unforeseen effects observed after 2017, including an extreme acceleration of the retreat of the inland lagoon margin from about 0.2 to 2 m/year. This was a consequence of the development of a large flood delta in an area of limited accommodation space, forcing the main tidal channel...

Coastal structures, such as groynes and breakwaters, disrupt coastal processes and often promote sediment accumulation updrift and erosion downdrift. However, complex or different groyne designs, such as curved groynes can lead to different behaviours that are still poorly understood. This study investigated the short-term morphological changes cau...

Coastal storms can cause erosion and flooding of coastal areas, often accompanied by significant social-economic disruption. As such, storm characterisation is crucial for an improved understanding of storm impacts and thus for coastal management. However, storm definitions are commonly different between authors, and storm thresholds are often sele...

Coastal dunes are important habitats that also play an important role in coastal protection. In areas of high tourist activity, they have often been degraded by trampling and intensive use, resulting in a loss of ecological, aesthetic and protective values. As a result, several management actions have been taken to minimise dune degradation and enh...

Sea level rise will be a major threat to coastal communities within the next century due to the intensity and severity of the floods it can cause. A new methodology considering water infiltration, slope, and hydraulic connectivity was developed to assess the potential inundation extension associated with different total water level and sea level ri...

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 variabili...

Beaches combined with sloping structures are frequently the first element of defense to protect urban areas from the impact of extreme coastal flooding events. However, these structures are rarely designed for null wave overtopping discharges, accepting that waves can pass above the crest and threat exposed elements in hinterland areas, such as ped...

The analysis of extreme wave conditions is crucial for understanding and mitigating coastal hazards. As global wave reanalyses allow to extend the evaluation of wave conditions to periods and locations not covered by in-situ measurements, their direct use is common. However, in coastal areas, the accuracy of global reanalyses is lower, particularly...

The impact of storms on barrier islands can be predicted with increasing accuracy due to the development of process-based models and the use of high-resolution datasets. However, data availability is restricted in space and time, and the potential use of hydrodynamic forcing from global wave reanalyses and topo-bathymetric grids from global digital...

Storm-induced erosion and shoreline retreat of barrier islands are assumed to be primarily controlled by the intensity of the hydrodynamic forcing and barrier morphology. However, less studied non-dynamic variables such as the underlying bedrock topography can mediate the morphological response in geologically controlled barrier systems. This work...

Communities can be vulnerable to wave-induced flooding and the risk is expected to increase with rising sea levels and population growth. Under this threat, early warning systems are relevant instruments for effective risk reduction strategies. These systems combine accurate hazard estimations with risk level classification for specific coastal rec...

High-energy storm events induce hazards that promote damage and destruction of property and infrastructure. Defining high-risk areas is therefore fundamental to prioritise management actions. This work presents the application of an approach to identify hotspots of storm impact at a regional scale (tens to hundreds of kilometres). The Coastal Risk...

Coastal dunes are fragile ecosystems emerging at the interface between marine and continental environments. They provide multiple services, among which are the protection against the impact of storms and the hosting of diverse and unique species of fauna and flora. However, changes in the topography or biological component of these systems may enda...

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...

Wave-induced flooding represents a threat and sea-level rise will exacerbate the problem. Bayesian Network tools that surrogate hydrodynamic and risk models were designed to predict risks induced by overwash/overtopping at Praia de Faro and Quarteira (Portugal) for current and future conditions. A 23.5 year-dataset of oceanic conditions for the 199...

Vegetation on coastal dunes is a key element, as it promotes the growth and stabilization of these landforms while contributing significantly to biodiversity. Physical (e.g. impact of storms), ecological (e.g. animal grazing) and human-related (e.g. farming and recreation) factors may disturb coastal dune vegetation, changing dune dynamics and even...

Coastal storms often cause damages and losses in occupied areas. Under climate change conditions (i.e. sea-level rise and increased frequency of extreme sea levels) and increasing human occupation, the consequences of coastal storms will be amplified if no adaptation actions are implemented. The selection of the best possible coastal management mea...

https://cmswebonline.com/iahr2022/epro/html/07-03-001-83.xml

The alongshore response of dunes to storm events can be extremely variable and, consequently, their capacity to maintain their services, including the protection of hinterland communities. In this study, the role of biotic and abiotic factors determining the magnitude of dune retreat driven by a severe storm along a 60 km barrier island system was...

Overwash is one of the most prominent hazards affecting coastal zones, and the associated consequences are expected to increase because of both sea-level rise and intensification of coastal occupation. This study used a 23-year data set of wave heights and tide-surge levels to define return periods of overwash potential for current and future sea-l...

Living by the coast is a high-risk choice, but most people do it voluntarily. At Faro Beach, a heavily urbanized settlement located on a sandy barrier peninsula exposed to coastal hazards, houses and roads were destroyed due to storm action. However, residents feel safe living there and have no intentions of relocating. The development and implemen...

Human occupation of and alteration of the world’s coast has transformed large stretches of it into Coupled Human-Natural Systems (CHANS) in which humans both influence and are influenced by coastal evolution. In such systems, human activity is as critical on natural resilience as processes and sediment supply derived from the natural setting. Pre-...

Recent and historic high-impact events have demonstrated significant flood risks to many coastal areas in Europe and across the globe. Understanding the behavior of humans in relation to risk management poses grand challenges for both natural and social sciences and humanities. The study analyzes the cultural aspects of coastal risk management and...

https://www.encontrociencia.pt/posters/22388_20201030191237_EC_2020_poster_LBS.pdf

Unmanned autonomous vehicles (UAV) are been increasingly used to monitor morphological changes in coastal areas. However, it is critical to understand the accuracy during the entire process to ensure low total errors in the products, especially at areas whit low changes rates (e.g. coastal dunes). Here, the use of UAV to analyse dune evolution was...

Numerical models are useful tools to predict the effects of storms in coastal areas. The objective of this work was to simulate the effects of storms in São Pedro de Moel beach by using XBeach. The nearshore sea state was obtained by propagating offshore conditions using the SWAN model. The XBeach model was divided into two setups to analyse overto...

Dunes are key elements of coastal landscapes in almost every latitude. They host high levels of biodiversity and provide important benefits to society; e.g. protection against floods and erosion, or recreation. Coastal dune growth is constrained by intrinsic factors, which are critical when managing dune systems or choosing coastal dune restoration...

Sedimentological, geochemical and benthic foraminiferal proxies were used to interpret changes of depositional environments in a mud entrapment inside the Guadiana River paleo-valley, northern Gulf of Cadiz, to understand the temporal variability of fluvial flooding events and to detect patterns of latitudinal climatic variability in western Iberia...

Applying the ecological resilience principles to barrier island geomorphological evolution requires approaches that perceive and interpret resilience far from predefined barrier characteristics and static views. Accepting that barrier islands, like all natural systems, are dynamic and adaptively changing in response to external disturbances is fund...

In a simple definition, beach rotation is the opposing movement of the shoreline along the two ends of an embayed beach, driven by longshore and/or cross-shore sediment transport in response to seasonal or periodic changes in wave direction and/or gradients in wave energy. However, when considered in detail, the mechanisms, drivers and timescales o...

López-Ruiz, A.; Garel, E., and Ferreira, Ó., 2020. The effects of high river discharges on the morphodynamics of the Guadiana ebb-tidal delta. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 558-562. Coconut Creek (Florida), ISSN 0749-0208. This work analyses the role of h...

Cabezas-Rabadán, C.; Pardo-Pascual, J.E.; Palomar-Vázquez, J.; Ferreira, Ó., and Costas, S., 2020. Satellite Derived Shorelines at an exposed meso-tidal beach. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1027–1031. Coconut Creek (Florida), ISSN 0749-0208. Shoreline pos...

At the Algarve south coast overwash-induced floods are a frequent and destructive phenomenon. In this study return periods for overwash potentials are estimated for two beaches located at the southwest coast of the Algarve (Carvoeiro and Salema) based on runup calculations for the period 1995-2017 after applying two well validated empirical formula...

Resilience has been used over a wide range of scientific fields and often ambiguously, causing confusion over terminology and concepts and giving rise to distinct interpretations and misconceptions, even within the same scientific discipline. Starting by providing clarifications and definitions of the main terminology and key principles of ecologic...

Overwash hydrodynamic datasets are mixed in quality and scope, being difficult to obtain due to fieldwork experimental limitations. Nevertheless, these measurements are crucial to develop reliable models to predict overwash. Aiming to overcome such limitations, this work presents accurate fieldwork data on overwash hydrodynamics, further exploring...

Human interventions on sandy barriers interfere strongly with natural barrier dynamics, to the extent of having become key moderators of geomorphological evolution. This work identifies and analyses natural and human-induced drivers and their importance to the multi-decadal evolution of a barrier system. The methodology, based on aerial photograph...

Current techniques assessing longshore sediment transport rates have large uncertainties, pleading for the development of alternative and complementary approaches. The present study proposes a method to estimate the decadal average rate of longshore transport at modern ebb‐tidal deltas based on a sediment budget analysis of the outer shoal growth....

This paper presents a study for estimating the size of a tidal turbine array for the Faro-Olhão Inlet (Potugal) using a surrogate optimization approach. The method compromises problem formulation, hydro-morphodynamic modelling, surrogate construction and validation, and constraint optimization. A total of 26 surrogates were built using linear RBFs...

Aerial photographic data and historical maps were used to identify trends, growth patterns and responses to anthropogenic disturbances in the barriers of the Ria Formosa system (South Portugal). Hard (inlet stabilizations, jetties) and soft (nourishments, inlet relocations) coastal works have influenced, to different extents, the recent (1952-2014)...

A B S T R A C T - This paper investigates the optimum tidal energy converter array density at a tidal inlet by applying surrogate-based optimisation. The SBO procedure comprises problem formulation, design of experiments, numerical simulations , surrogate model construction and constrained optimisation. This study presents an example for the Faro-O...

https://authors.elsevier.com/a/1YBjuB8ccghei (download for free until 27 January 2019) 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 conse...

The services of a coastal ecosystem are critical to the functioning of the Earth’s life-support systems, and they are intimately governed by biotic and geologic couplings. This work assesses the temporal evolution of salt marsh ecosystems in a coastal lagoon, Ria Formosa lagoon, and analysis its triggering processes, both natural processes and huma...

Projections from the Intergovernmental Panel on Climate Changes (IPCC) point to a global mean sea level rise (SLR) of close to 1 m by 2100 for a worst-case scenario. This will have a significant impact on coastal areas worldwide, primarily by modifying the shoreline position and coastal morphology, but also by influencing the coastal economy and li...

The aim of the present paper is to analyse the recent morphological evolution of the sandy barriers of Ria Formosa, a multi-inlet system located in South Portugal, to assess evolution regimes and related controlling factors and to identify resilience mechanisms in response to natural and artificial drivers of change. The data collected comprise aer...

Assessing the impact of changes on the environment driven by natural or anthropogenic forcers includes the comparison between antecedent and post-event conditions. The latter is particularly relevant in order to better understand to which extent those changes actually impact or alter a particular environment and associated services and to determine...

This study evaluates the patterns and effects of relative sea-level rise on the tidal circulation of the basin of the Ria Formosa coastal lagoon using a process-based model that is solved on an unstructured mesh. To predict the changes in the lagoon tidal circulation in the year 2100, the model is forced by tides and a static sea level. The bathyme...

The present paper contributes to assessing the resilience of a complex barrier island environment, namely of the Ria Formosa multi-inlet system in southern Portugal. The long-term morphologic evolution of four study areas during the last 60 years (1947 to 2014) is analysed based on aerial photographs, including the environments of oceanic and backb...

Faro Beach is a vulnerable and heavily urbanized settlement in the Ria Formosa barrier island system, exposed to beach erosion, overwash and other hazards that have resulted in house and road destruction. Residents have accepted the risks in exchange for the benefits of living at the beach. Previous qualitative studies have suggested that residents...

Assessing the impact of changes on the environment driven by natural or anthropogenic forcers includes the comparison between antecedent and post-event conditions. The latter is particularly relevant in order to better understand to which extent those changes actually impact or alter a particular environment and associated services and to determine...

Pocket beaches on rocky coasts with headlands that control hydro-sedimentary processes are considered to be constrained sedimentary systems, generally with limited sediment inputs. Pocket beaches face severe changes over time. Under worst-case scenarios, these changes can result in the loss of the beach, causing waves to directly attack adjacent cl...

A coastal hazard indicator is a measure of the state of coastal systems in relation to a given hazard, synthesizing complex information in a simple and resumed format. Coastal hazard indicators are commonly used to prioritize coastal vulnerability or assess the potential (or effective) impact of storms and should be used to facilitate coastal manag...

Free access on this link until April 25, 2018 https://authors.elsevier.com/a/1WgCn1M2DU~hr3 Coastal zones are under increasing risk as coastal hazards increase due to climate change and the consequences of these also increase due to on-going economic development. To effectively deal with this increased risk requires the development of validated t...

Abstract Coastal communities are threatened by the impact of severe storms that may cause significant loss of life and damage to properties. Among the main processes behind such impacts on coastal barriers are the occurrence of overwash and breaching during storm events. In order to estimate potential losses associated with a particular event, the...

Recent and historic low-frequency, high-impact events have demonstrated the flood risks faced by exposed coastal areas in Europe and beyond. These coastal zone risks are likely to increase in the future which requires a re-evaluation of coastal disaster risk reduction (DRR) strategies and a new mix of PMP (prevention, e.g., dike protection; mitigat...

Traditionally, enhanced aeolian activity has been associated both to human derived disturbances in the vegetation cover and to the impact of storminess periods responsible for intense winds and thus enhanced dune mobility. Here, we investigate the positive impact that both factors may have on aeolian sediment transport by directly affecting the bea...

http://www.sociedadgeologica.es/archivos/GEO_TEMAS/Geo_temas17.pdf

The morphological variability of a berm-bar system is highly dependent on wave conditions with direct consequences for the evolution of the nearby coast; however, an understanding of this variability based on field measurements is still lacking, in particular with respect to the assessment of both longshore and cross-shore components. In this study...

This study aims to evaluate the influence of the dried meat industry and the river harbour in the process of littoralisation in Ceará. However, it is necessary to investigate diachronically how this occurred between the 17th and 18th centuries, because colonial Ceará did not arouse the interest of the conqueror, because it did not offer favorable e...

Managing coastal risk at the regional scale requires a prioritization of resources along the shoreline. A transparent and rigorous risk assessment should inform managers and stakeholders in their choices. This requires advances in modelling assessment (e.g., consideration of source and pathway conditions to define the probability of occurrence, non...

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. wav...

An historical analysis of the occurrence of storms and their damage intensity is presented. The work analysed historical large-scale events from The Middle Ages to the 1960s at case study sites along the coasts of North Norfolk (UK); Charente-Maritime and Vendée (France); Cinque Terre-Liguria coast (Italy); Emilia-Romagna coast (Italy) and Ria Form...

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...

Overwash hydrodynamics datasets are mixed in quality and scope, being hard to obtain due to fieldwork experimental difficulties. Aiming to overcome such limitations, this work presents accurate fieldwork data on overwash hydrodynamics, further exploring it to model overwash on a low-lying barrier island. Fieldwork was performed on Barreta Island (P...

Overwash hydrodynamics were measured during a storm event. Data from literature and fieldwork were used to setup a numerical model, using XBeach in non-hydrostatic mode. Different simulations were conducted to assess the influence of several factors on overwash statistics. Nearshore morphology was found to greatly influence overwash. Sediment mean...

The present paper focusses on the objectives and methodology of the EVREST project regarding the identification of natural mechanisms that promote resilience in barrier island systems, both in oceanfront and backbarrier environments. The study area of the project is the Ria Formosa barrier island system, located in southern Portugal.

Final policy brief from the Resilience Increasing Strategies for Coasts - Toolkit (RISC-KIT) summarizing key recommendations for policy makers from the implementation of the toolkit in 10 European cities.

This Synthesis Report provides an overview of the achievements, lessons learned and challenges identified through the RISC-KIT project activities, including the development and application of the tools at ten case study sites in a range of coastal regions across Europe. The lessons learned are then fed into a series of recommendations for improved...

The Resilience-Increasing Strategies for Coasts – Toolkit (RISC-KIT) FP7 EU project (2013-2017) aims to produce a set of innovative and EU-coherent open-source and open- access methods, tools and management approaches (the RISC-KIT) in support of coastal managers, decision-makers and policy makers to reduce risk and increase resilience to low- freq...

An historical analysis of the occurrence of storms and their damage intensity is presented. The work analysed historical large-scale events from The Middle Ages to the 1960s at case study sites along the coasts of North Norfolk (UK); Charente-Maritime and Vendee (France); Cinque Terre-Liguria coast (Italy); Emilia-Romagna coast (Italy) and Ria Form...