Geological control of beach morphodynamic state

Jackson, Derek W.T.; Cooper, J. Andrew G.; Río, Laura Del

doi:10.1016/j.margeo.2005.02.021

Cited by 188 publications

(118 citation statements)

References 22 publications

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“…Compared to other beaches described in the literature, Perranporth is most similar to Truc Vert (Castelle et al, 2007;Senechal et al, 2009;Coco et al, 2014), although the latter beach is characterised by more energetic wave conditions and a smaller tide range. There is no obvious effect of geological control on the beach morphology (cf., Jackson et al, 2005;Loureiro et al, 2012;van de Lageweg et al, 2013); however, the beach is quite long (c. 3.5 km; Figure 1) and can be considered uninterrupted, despite being embayed.…”

Section: Discussionmentioning

confidence: 99%

“…Other follow-up studies presented alternative models more suitable for different types of environments; for example, multi-bar beaches (Short and Aagaard, 1993;Short, 1992), low-wave energy settings (Hegge et al, 1996;Jackson et al, 2002) and large tidal environments (Short, 1991;Masselink and Short, 1993;Masselink and Hegge, 1995). More recently, studies along rocky coasts and embayed beaches highlighted the role of geology in constraining beach morphological development (Jackson et al, 2005), invoking the identification of distinctly different beach state models for geologically-controlled beaches (Loureiro et al, 2012). Nevertheless, the most comprehensive and rigorous longitudinal study of beach types so far by Scott et al (2011), including almost one hundred wave-dominated, tide-affected and geologically-controlled beach settings in the UK, confirmed the general validity of the Wright and Short (1984) model.…”

Section: Introductionmentioning

confidence: 99%

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Role of wave forcing, storms and NAO in outer bar dynamics on a high-energy, macro-tidal beach

et al. 2014

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Outer sand bar dynamics on a high-energy macro-tidal beach were investigated using long-term (multi-year) field datasets of intertidal morphology and offshore bathymetry. Utilising a 15-year time-series of Argus video images, five distinct outer bar types were identified: Mega Rip, Longshore, Crescentic, Crescentic Attached and Welded. The most common classification was Crescentic Attached, with the outer bar oscillations being out of phase with the inner bar oscillations, as would be expected for the shore-normal wave approach at this site. The outer bar had a typical amplitude of 0.5-1 m and a longshore wavelength of 600 m. Changes in outer bar morphology were related to measured and modelled nearshore wave data. However, the outer bar morphology changed over a much longer time scale (monthly-to-annual) than the daily-to-weekly variations in wave height and period. An extended duration of energetic wave action was required to bring about an upstate bar transition to the Longshore or Mega Rip state, where the bar then remained arrested for a significant amount of time, requiring several months of low wave conditions to induce a down state transition through Crescentic to Welded. This slow morphological response is explained by extended relaxation times attributed to the large tidal range at the study site where the outer bar morphology is only active for part of the tidal cycle (several hours around low tide). The configuration and position of the outer bar were related: the more upstate (downstate) bar types being associated with a more offshore (onshore) bar position. The detrended outer bar position was significantly related to a forcing term based on wave power and disequilibrium of the dimensionless fall velocity with offshore (onshore) bar migration occurring when wave conditions were more (less) energetic that the antecedent conditions. The upstate end member (Longshore or Mega Rip) was attained sometime during the winter months for 14 out of the 16 years of monitoring; the outer bar remained attached to the low tide shoreline over the winter 2005/2006 and 2010/2011. These two winters with incomplete upstate cycles were characterised by the lowest winter wave conditions and negative winter North Atlantic Oscillation (NAO) indices, suggesting that the winter NAO is correlated with both beach state and nearshore bar configuration. KEYWORDS

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Role of wave forcing, storms and NAO in outer bar dynamics on a high-energy, macro-tidal beach

et al. 2014

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“…Jackson et al (2005) resgatam a idéia de que todas as praias estão apoiadas sobre uma estrutura geológica antecedente e é essa estrutura que determina os limites pelos quais a praia se forma e se espacializa. Os processos hidrodinâmicos que irão influenciar a dinâmica dos ambientes praiais podem ser controlados pela disposição desta estrutura geológica, como a presença de costões rochosos, ilhas, lajes submersas etc.…”

Section: Praias De Enseadaunclassified

Impactos costeiros induzidos por ondas de tempestade entre o Cabo Frio e o Cabo Búzios, Rio de Janeiro, Brasil

Bulhões

Fernández

Filho

et al. 2014

ABEQUA

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Quaternary and Environmental Geosciences (2014) 05(2):155-165Papel da praia na proteção da costa e as alterações oceanográficas em diferentes escalas temporais AbstractThe wave field in deep waters is notable for its variability and dictates the energy that will be directed towards the coast. Morphological impacts on coastal environments depend on the magnitude of the meteorological and oceanographic forcings and the beach capabilities of absorbing this energy. In the analysis between Cape Frio and Cape Buzios, we considered the textural characteristics of the inner continental shelf from the analysis of 394 samples, the volumetric variability of 438 surveys along 17 beach profiles and characteristics of 69 storms between 2003 and 2013. Results showed that sedimentation in the nearshore, through the mean grain size parameter, reflects the areas with higher or lower wave energy. The results also indicated the occurrence of a "storm waves season" between April and September, and this is the main element associated with erosion of subaereal stock on beaches. A period with no occurrence of these storm waves the recovery of this subaereal sandy stock tend to occur. The different segments of beach show the greater or lesser magnitude of these effects, depending primarily on the orientation and exposure of each beach segment. Isolated storms with greater magnitude tend to promote severe erosion, especially if they occur at the beginning of this "season of storm waves".

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“…On one hand, within natural controls, the main contributing agents are geological framework, sediment supply and wave climate (e.g. Jackson et al, 2005;Dissanayake et al, 2015;Masselink et al, 2016). On the other hand, within anthropogenic controls, land use transformation, coastal development and the construction of engineering structures at the coast (such as jetties) and in river basins (dams) are the major causes of shoreline erosion (e.g.…”

Section: Introductionmentioning

confidence: 99%

Contribution of storms to shoreline changes in mesotidal dissipative beaches: case study in the Gulf of Cádiz (SW Spain)

Puig¹,

Río²,

Plomaritis

et al. 2016

Nat. Hazards Earth Syst. Sci.

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Abstract. In this study an analysis of storminess and rates of shoreline change is performed and discussed jointly in four geomorphological units of the Gulf of Cádiz (SW Spain) for the period of 1956-2010. For this purpose, storm events are identified based on the following characteristics: wave height above 2.5 m, a minimum duration of 12 h and events with calm periods of less than 24 h were considered as a single event. Subsequently, energy parameters are determined in order to characterize storm-induced impacts. Conversely, geographic information system (GIS) tools are used to measure shoreline changes in aerial photographs and orthophotographs of each site, selecting the high water line as shoreline proxy. Each geomorphological unit is divided into different behavioural patterns according to recorded coastal changes, so that each one shows a particular behaviour.In general the variability of shoreline changes that is explained by storms and the relation between storm parameters and coastal changes present better results in exposed areas (Cádiz and Vistahermosa) than in sheltered areas (Valdelagrana spit barrier) because the former are more sensitive to storm impacts. On the contrary, in areas where there is no relation between coastal changes and storm parameters (Valdelagrana and Sancti Petri sand spit), it is suggested that anthropogenic factors are the main forcing agents determining shoreline behaviour. However, in these areas the storminess also modulates coastline recession by increasing erosion when the number of storms is high.

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Geological control of beach morphodynamic state

Cited by 188 publications

References 22 publications

Role of wave forcing, storms and NAO in outer bar dynamics on a high-energy, macro-tidal beach

Role of wave forcing, storms and NAO in outer bar dynamics on a high-energy, macro-tidal beach

Impactos costeiros induzidos por ondas de tempestade entre o Cabo Frio e o Cabo Búzios, Rio de Janeiro, Brasil

Contribution of storms to shoreline changes in mesotidal dissipative beaches: case study in the Gulf of Cádiz (SW Spain)

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