Morphodynamics of reflective and dissipative beach and inshore systems: Southeastern Australia

Wright, L. D.; Chappell, John; Thom, B. G.; Bradshaw, Mark; Cowell, Peter J.

doi:10.1016/0025-3227(79)90149-x

Cited by 322 publications

(189 citation statements)

References 27 publications

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“…First, it describes the nature of the swash spectrum, and is therefore consistent with previous work characterising beach-states on the basis of wave and current spectra in the surf zone (Wright et al, 1979;Wright, 1982). Second, the magnitude and distribution of swash spectral energy…”

Section: General Conceptssupporting

confidence: 84%

“…Incident long-waves and those generated inside the surf zone are important on dissipative beaches and their energy is almost entirely reflected on even the most gently sloped beaches (Huntley and Bowen, 1975). Short (1979) and Wright et al (1979) added four intermediate beach-states, recognising the more complex threedimensional morphologies that can exist.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…Not only can a range of modal beach-states exist along a coastline that represent localized combinations of modal incident wave conditions and sediment size, but a single beach can alter beach-state with synoptic variations in incident wave conditions or longer term changes in the size of the beach sediment (Short, 1979;Wright et al, 1979;Short, 1984). Depending on localized conditions such as sediment size, wave climate, degree of embayment and other factors limiting the range of wave breaker heights (and Ω); a given beach can display either the full-range or a subset of beach-states through time .…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…Two seminal papers published in 1979 introduced the now widely recognised morphodynamic beach-state model for microtidal, high-energy beaches (Short, 1979;Wright et al, 1979). The beach-state model classified beaches according to morphology and surf zone hydrodynamics.…”

Section: Introductionmentioning

confidence: 99%

“…This ordered behavior means that by studying a set of several different beaches that represent a range of beach-states, insight can be gained into how morphodynamic processes evolve with cycles of incident wave energy. This approach has been used previously to propose evolving patterns of surf zone hydrodynamics (Wright et al, 1979;Wright, 1982) and sediment transport (Aagaard et al, 2013) associated with storm and post-storm cycles. We adopt a similar approach here to propose how swash spectral energy distributions evolve with a beach's morphodynamic response to changing levels of incident wave energy.…”

mentioning

confidence: 99%

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Spectral signatures for swash on reflective, intermediate and dissipative beaches

et al. 2014

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In this paper we synthesise a large data set gathered from a wide variety of field deployments and integrate it with previously published results to identify the spectral signatures of swash from contrasting beach types. The field data set includes the full range of micro-tidal beach types (reflective, intermediate and dissipative), with beach gradients ranging from approximately 1:6 to 1:60 exposed to offshore significant wave heights of 0.5 m to 3.0 m.The ratio of swash energy in the short-wave (f>0.05 Hz) to long-wave (f<0.05 Hz) frequency bands is found to be significantly different between the three beach types. Swash energy at short-wave frequencies is dominant on reflective and intermediate beaches and swash at long-wave frequencies is dominant on dissipative beaches; consistent with previously reported spectral signatures for the surf zone on these beach types.The available swash spectra were classified using an automated algorithm (CLARA) into five different classes. The ordered classes represent an evolution in the spectrum shape, described by a frequency downshifting of the energy peak from the short-wave into the longwave frequency band and an increase in the long-wave swash energy level compared to a relatively minor variation in the short-wave swash energy level. A universally common feature of spectra from all beach-states was an 4  f energy roll-off in the short-wave frequency band. In contrast to the broadly uniform appearance of the short-wave frequency band, the appearance of the long wave frequency band was highly variable across the beachstates. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

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Section: General Conceptssupporting

confidence: 84%

Section: Accepted M Manuscriptmentioning

confidence: 99%

Section: Accepted M Manuscriptmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Spectral signatures for swash on reflective, intermediate and dissipative beaches

et al. 2014

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Forecasting the response of Earth's surface to future climatic and land use changes: A review of methods and research needs

et al. 2015

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In the future, Earth will be warmer, precipitation events will be more extreme, global mean sea level will rise, and many arid and semiarid regions will be drier. Human modifications of landscapes will also occur at an accelerated rate as developed areas increase in size and population density. We now have gridded global forecasts, being continually improved, of the climatic and land use changes (C&LUC) that are likely to occur in the coming decades. However, besides a few exceptions, consensus forecasts do not exist for how these C&LUC will likely impact Earth-surface processes and hazards. In some cases, we have the tools to forecast the geomorphic responses to likely future C&LUC. Fully exploiting these models and utilizing these tools will require close collaboration among Earth-surface scientists and Earth-system modelers. This paper assesses the state-of-the-art tools and data that are being used or could be used to forecast changes in the state of Earth's surface as a result of likely future C&LUC. We also propose strategies for filling key knowledge gaps, emphasizing where additional basic research and/or collaboration across disciplines are necessary. The main body of the paper addresses cross-cutting issues, including the importance of nonlinear/threshold-dominated interactions among topography, vegetation, and sediment transport, as well as the importance of alternate stable states and extreme, rare events for understanding and forecasting Earth-surface response to C&LUC. Five supplements delve into different scales or process zones (global-scale assessments and fluvial, aeolian, glacial/periglacial, and coastal process zones) in detail.

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Understanding coastal morphodynamic patterns from depth‐averaged sediment concentration

Ribas

Falqués

Swart

et al. 2015

Reviews of Geophysics

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This review highlights the important role of the depth‐averaged sediment concentration (DASC) to understand the formation of a number of coastal morphodynamic features that have an alongshore rhythmic pattern: beach cusps, surf zone transverse and crescentic bars, and shoreface‐connected sand ridges. We present a formulation and methodology, based on the knowledge of the DASC (which equals the sediment load divided by the water depth), that has been successfully used to understand the characteristics of these features. These sand bodies, relevant for coastal engineering and other disciplines, are located in different parts of the coastal zone and are characterized by different spatial and temporal scales, but the same technique can be used to understand them. Since the sand bodies occur in the presence of depth‐averaged currents, the sediment transport approximately equals a sediment load times the current. Moreover, it is assumed that waves essentially mobilize the sediment, and the current increases this mobilization and advects the sediment. In such conditions, knowing the spatial distribution of the DASC and the depth‐averaged currents induced by the forcing (waves, wind, and pressure gradients) over the patterns allows inferring the convergence/divergence of sediment transport. Deposition (erosion) occurs where the current flows from areas of high to low (low to high) values of DASC. The formulation and methodology are especially useful to understand the positive feedback mechanisms between flow and morphology leading to the formation of those morphological features, but the physical mechanisms for their migration, their finite‐amplitude behavior and their decay can also be explored.

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Morphodynamics of reflective and dissipative beach and inshore systems: Southeastern Australia

Cited by 322 publications

References 27 publications

Spectral signatures for swash on reflective, intermediate and dissipative beaches

Spectral signatures for swash on reflective, intermediate and dissipative beaches

Forecasting the response of Earth's surface to future climatic and land use changes: A review of methods and research needs

Understanding coastal morphodynamic patterns from depth‐averaged sediment concentration

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