An integrated method for the determination of set-back lines for coastal erosion hazards on sandy shores

Ferreira, Óscar; Garcia, Tiago; Matias, Ana; Taborda, Rui; Dias, João Alveirinho

doi:10.1016/j.csr.2005.12.016

Cited by 110 publications

(78 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The dune overwash predictions were realistic, and the identified vulnerable areas came in good agreement with field observations and previous studies in the area (Almeida et al 2011b;Ferreira et al 2006). Even though a constant beach-face slope value was considered for the entire study area, during the dune overwash predictions, the approach could be easily modified for alongshore variable β.…”

Section: Dune Overwash Predictionssupporting

confidence: 69%

Coastal vulnerability assessment based on video wave run-up observations at a mesotidal, steep-sloped beach

2011

View full text Add to dashboard Cite

Coastal imagery obtained from a coastal video monitoring station installed at Faro Beach, S. Portugal, was combined with topographic data from 40 surveys to generate a total of 456 timestack images. The timestack images were processed in an open-access, freely available graphical user interface (GUI) software, developed to extract and process time series of the cross-shore position of the swash extrema. The generated dataset of 2% wave run-up exceedence values R 2 was used to form empirical formulas, using as input typical hydrodynamic and coastal morphological parameters, generating a best-fit case RMS error of 0.39 m. The R 2 prediction capacity was improved when the shore-normal wind speed component and/or the tidal elevation η tide were included in the parameterizations, further reducing the RMS errors to 0.364 m. Introducing the tidal level appeared to allow a more accurate representation of the increased wave energy dissipation during low tides, while the negative trend between R 2 and the shorenormal wind speed component is probably related to the wind effect on wave breaking. The ratio of the infragravityto-incident frequency energy contributions to the total swash spectra was in general lower than the ones reported in the literature E infra /E inci >0.8, since low-frequency contributions at the steep, reflective Faro Beach become more significant mainly during storm conditions. An additional parameterization for the total run-up elevation was derived considering only 222 measurements for which η total,2 exceeded 2 m above MSL and the best-fit case resulted in RMS error of 0.41 m. The equation was applied to predict overwash along Faro Beach for four extreme storm scenarios and the predicted overwash beach sections, corresponded to a percentage of the total length ranging from 36% to 75%.

show abstract

Section: Dune Overwash Predictionssupporting

confidence: 69%

Coastal vulnerability assessment based on video wave run-up observations at a mesotidal, steep-sloped beach

2011

View full text Add to dashboard Cite

show abstract

“…Considering that this study targets low-lying sandy coasts backed by dunes, the coastline indicator used in this study was the foredune toe, and recognized as the morphological feature less affected by short-term (tidal) and medium-term (seasonal) changes (e.g. Komar et al, 2001;Ferreira et al, 2006;Del Río and Gracia, 2013).…”

Section: Beach Coastline Indicatormentioning

confidence: 99%

“…Abecassis et al, 1970;Barceló, 1971;Castanho et al, 1974;Bettencourt and Ângelo, 1992;Ferreira, 1992;Oliveira, 2005;Pinto and Teixeira, 2005;VelosoGomes et al, 2009;Taveira Pinto et al, 2009;Rebêlo et al, 2011;Silva et al, 2013), and different coastline proxies are used (e.g. European Commission, 2004;Oliveira, 2005;Ferreira et al, 2006;Rebêlo et al, 2011;Cenci et al, 2013). Thus, these analyses can not provide a complete and unified approach for all of the Portuguese territory.…”

Section: Introductionmentioning

confidence: 99%

Coastline evolution of Portuguese low-lying sandy coast in the last 50 years: an integrated approach

Lira

Silva

Taborda

et al. 2016

Earth Syst. Sci. Data

Self Cite

View full text Add to dashboard Cite

Abstract. Regional/national-scale information on coastline rates of change and trends is extremely valuable, but these studies are scarce. A widely accepted standardized methodology for analysing long-term coastline change has been difficult to achieve, but it is essential to conduct an integrated and holistic approach to coastline evolution and hence support coastal management actions. Additionally, databases providing knowledge on coastline evolution are of key importance to support both coastal management experts and users.The main objective of this work is to present the first systematic, national-scale and consistent long-term coastline evolution data of Portuguese mainland low-lying sandy coasts.The methodology used quantifies coastline evolution using a unique and robust coastline indicator (the foredune toe), which is independent of short-term changes.The dataset presented comprises (1) two polyline sets, mapping the 1958 and 2010 sandy beach-dune system coastline, both optimized for working at 1 : 50 000 scale or smaller; (2) one polyline set representing long-term change rates between 1958 and 2010, each estimated at 250 m; and (3) a table with minimum, maximum and mean of evolution rates for sandy beach-dune system coastline. All science data produced here are openly accessible at https://doi.pangaea.de/10.1594/PANGAEA.859136 and can be used in other studies.Results show beach erosion as the dominant trend, with a mean change rate of −0.24 ± 0.01 m year −1 for all mainland Portuguese beach-dune systems. Although erosion is dominant, this evolution is variable in signal and magnitude in different coastal sediment cells and also within each cell. The most relevant beach erosion issues were found in the coastal stretches of Espinho-Torreira and Costa Nova-Praia de Mira, Cova da Gala-Leirosa, and Cova do Vapor-Costa da Caparica. The coastal segments Minho River-Nazaré and Costa da Caparica adjacent to the coast exhibit a history of major human interventions interfering with the coastal system, many of which originated and maintained a sediment deficit. In contrast, the coastal segments Troia-Sines and SinesCape S. Vicente have experienced less intervention and show stable or moderate accretion behaviour.

show abstract

“…During extreme conditions, most hydro-and morphodynamic processes are accelerated, with the most dramatic implication being the fact that the water level can exceed the height of natural (e.g., dunes, cliffs) or anthropic barriers (e.g., sea walls, dykes), and reach areas not prepared to interact with the water element, often with catastrophic consequences. This is the reason that marine storms are considered as extreme when they coincide with coastal inundation, and inundation maps are a crucial element for several coastal management and engineering practices, i.e., post-evaluation of extreme events, coastal planning, definition of set-back lines (Ferreira et al, 2006), and evaluation of adaptation options (Cooper and Pile, 2014;Hinkel et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Developments in large-scale coastal flood hazard mapping

Vousdoukas

Voukouvalas

Mentaschi

et al. 2016

Nat. Hazards Earth Syst. Sci.

193

157

View full text Add to dashboard Cite

Abstract. Coastal flooding related to marine extreme events has severe socioeconomic impacts, and even though the latter are projected to increase under the changing climate, there is a clear deficit of information and predictive capacity related to coastal flood mapping. The present contribution reports on efforts towards a new methodology for mapping coastal flood hazard at European scale, combining (i) the contribution of waves to the total water level; (ii) improved inundation modeling; and (iii) an open, physics-based framework which can be constantly upgraded, whenever new and more accurate data become available. Four inundation approaches of gradually increasing complexity and computational costs were evaluated in terms of their applicability to large-scale coastal flooding mapping: static inundation (SM); a semidynamic method, considering the water volume discharge over the dykes (VD); the flood intensity index approach (Iw); and the model LISFLOOD-FP (LFP). A validation test performed against observed flood extents during the Xynthia storm event showed that SM and VD can lead to an overestimation of flood extents by 232 and 209 %, while Iw and LFP showed satisfactory predictive skill. Application at panEuropean scale for the present-day 100-year event confirmed that static approaches can overestimate flood extents by 56 % compared to LFP; however, Iw can deliver results of reasonable accuracy in cases when reduced computational costs are a priority. Moreover, omitting the wave contribution in the extreme total water level (TWL) can result in a ∼ 60 % underestimation of the flooded area. The present findings have implications for impact assessment studies, since combination of the estimated inundation maps with population exposure maps revealed differences in the estimated number of people affected within the 20-70 % range.

show abstract

An integrated method for the determination of set-back lines for coastal erosion hazards on sandy shores

Cited by 110 publications

References 12 publications

Coastal vulnerability assessment based on video wave run-up observations at a mesotidal, steep-sloped beach

Coastal vulnerability assessment based on video wave run-up observations at a mesotidal, steep-sloped beach

Coastline evolution of Portuguese low-lying sandy coast in the last 50 years: an integrated approach

Developments in large-scale coastal flood hazard mapping

Contact Info

Product

Resources

About