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This paper investigates bar migration in a fetch limited strong wind bay (Seaford Beach SE Australia). Onshore bar migration on open ocean beaches is dependant on long period swell wave and occurs during low energy conditions. However, in a fetch limited environment such waves are absent and most studies suggest that during low energy conditions the beach remains in an arrested state (Jackson et al. 2002). This paper spans a three month study period (15th March - 8th June 2008). Measurement of near shore morphology and wind data were collected. The two bars at Seaford behaved very differently; both onshore and offshore migration was detected during the three recorded storm events. The paper found that, firstly, wave breaking was incomplete in the middle bar during event 1 - the inner bar migrated offshore. Secondly wave breaking in the middle bar was almost complete during event 2 and the inner bar migrated onshore. Thirdly when wave breaking was complete in the middle bar during event 3 - the inner bar remained arrested on some profiles but bar height increased on others. The wave steepness threshold for onshore migration of the inner bar was parameterized s 0.041 - 0.042. Beach sediment modeling in fetch limited strong wind bays remains understudied. Our results should help to improve the predictive capability of beach sediment budgets in fetch limited strong wind bays. [ABSTRACT FROM AUTHOR]

The decay of seismic amplitude is caused by a variety of physical phenomena that can be divided broadly into elastic transmission losses (including geometrical spreading, interface transmission losses and scattering attenuation) and intrinsic attenuation, where wave energy is converted into heat due to viscous friction. The so‐called statistical averaging method is currently considered as the most advanced sonic wave attenuation estimation method, and there exist various implementations of this method. But the way elastic transmission losses – that mask the true intrinsic attenuation – are compensated for appears to be an issue and in some cases this correction has been overlooked. In this paper, we revisit the statistical averaging method for intrinsic attenuation estimation with particular focus on the role of elastic transmission losses. Through synthetic examples, we demonstrate the importance of compensating for elastic transmission losses even if the variation of velocity and density with depth is not notable. Our implementation of the method uses finite‐difference simulations thereby providing a versatile and accurate way to generate synthetic seismograms. We use a combination of elastic and viscoelastic finite‐difference simulations to demonstrate the significant error without accurate compensation of the elastic transmission losses. We apply our implementation of the method to sonic waveforms acquired in an exploration well from Browse basin, Australia. The resulting intrinsic attenuation estimates are indeed indicative of gas‐saturated zones identified from petrophysical analysis in which viscous friction are thought to be of importance. [ABSTRACT FROM AUTHOR]

Hybrid offshore renewable energy platforms have been proposed to optimise power production and reduce the levelised cost of energy by integrating or co-locating several renewable technologies. One example is a hybrid wave-wind energy system that combines offshore wind turbines with wave energy converters (WECs) on a single floating foundation. The design of such systems involves multiple parameters and performance measures, making it a complex, multi-modal, and expensive optimisation problem. This paper proposes a novel, robust and effective multi-objective swarm optimisation method (DMOGWA) to provide a design solution that best compromises between maximising WEC power output and minimising the effect on wind turbine nacelle acceleration. The proposed method uses a chaotic adaptive search strategy with a dynamic archive of non-dominated solutions based on diversity to speed up the convergence rate and enhance the Pareto front quality. Furthermore, a modified exploitation technique (Discretisation Strategy) is proposed to handle the large damping and spring coefficient of the Power Take-off (PTO) search space. To evaluate the efficiency of the proposed method, we compare the DMOGWA with four well-known multi-objective swarm intelligence methods (MOPSO, MALO, MODA, and MOGWA) and four popular evolutionary multi-objective algorithms (NSGA-II, MOEA/D, SPEA-II, and PESA-II) based on four potential deployment sites on the South Coast of Australia. The optimisation results demonstrate the dominance of the DMOGWA compared with the other eight methods in terms of convergence speed and quality of solutions proposed. Furthermore, adjusting the hybrid wave-wind model's parameters (WEC design and PTO parameters) using the proposed method (DMOGWA) leads to a considerably improved power output (average proximate boost of 138.5%) and a notable decline in wind turbine nacelle acceleration (41%) throughout the entire operational spectrum compared with the other methods. This improvement could lead to millions of dollars in additional income per year over the lifespan of hybrid offshore renewable energy platforms. • A new multiobjective optimisation method proposed and enhanced hybrid wave-wind platform. • A new combination of chaotic adaptive exploration and dynamic archive is introduced. • Effective and practical discretisation method improved performance of hybrid platform. • The performance of the proposed optimiser is validated on four real sea studies. [ABSTRACT FROM AUTHOR]

Offshore wind energy and wave energy are two exploitable sources of renewable energy available in the same marine environment. A co-located energy harvesting system of these two resources has the potential to play a leading role in the recent renewable energy mix mandate. A co-located system of mature offshore wind technology and a nascent wave energy technology can exploit the synergies of the two technologies, including the reduced cost, the easy operation and maintenance, and more importantly the potential of decreased power variability. This paper deals with a multi-site analysis of wind and wave power resources, and the estimation of exploitable energy through different wind turbines and wave energy converters (WECs). Results are presented for NSW Australia, but the devised strategy is generic and can be implemented in any region. Ten WECs, with different operating principles, are used for the estimation of the exploitable wave power, and the best performing converter is considered for the co-located wind-wave farm. A power fluctuation factor is introduced to quantify the reduction in power variability of the co-located wind-wave farm. Different percentage mixes of wind and wave energy are evaluated for the co-located wind-wave farm in the multi-site analysis. •A multi-site analysis of wind and wave for estimation of exploitable energy. •Performance evaluation of wind and wave energy conversion technologies. •Power variability representation with power fluctuation factor for a co-located farm. •Characterization of percentage share of wind and wave in a co-located farm. [ABSTRACT FROM AUTHOR]

The peak period of an energy-generating wave is one of the most important parameters that describe the spectral shape of the oceanic wave, as this indicates the duration for which the waves prevail with respect to their maximum extractable energy. In this paper, a half-hourly peak wave energy period (T P) forecast model is constructed using a suite of statistically significant lagged inputs based on the partial auto-correlation function with an extreme learning machine model developed and its predictive utility is benchmarked against deep learning models, i.e., convolutional neural network (CNN/CovNet) and recurrent neural network (RNN) models and other traditional M5tree, Conditional Maximization based Multiple Linear Regression (MLR-ECM) and MLR models. The objective model (ELM) vs. the comparison models (CNN, RNN, M5tree, MLR-ECM, and MLR) were trained and validated independently on the test dataset obtained from coastal zones of eastern Australia that have a high potential for implementation of wave energy generation systems. The outcomes ascertain that the ELM model can generate significantly accurate predictions of the half-hourly peak wave energy period, providing a good level of accuracy relative to deep learning models in selected coastal study zones. The study establishes the practical usefulness of the ELM model as being a noteworthy methodology for the applications in renewable and sustainable energy resource management systems. • A real-time peak wave energy period forecasting model is constructed using ELM model. • The advance ELM is benchmarked against a deep learning and other traditional models. • The advance ELM generates better predictions than deep learning models in this region. • ELM model provides significant energy management implications for ocean waves. [ABSTRACT FROM AUTHOR]

Short, A D, 2016. The Coastal Studies Unit and development of the Australian beach models. In: Vila-Concejo, A.; McCarroll, R.J.; Kennedy, D.M., and Bruce, E. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1-7. Coconut Creek (Florida), ISSN 0749-0208. The Australian coast provides an ideal laboratory in which to undertake beach research on a continental scale. The 30 000 km of open coast surrounds an entire continent that ranges from tropical to temperate latitudes (9-43°S); with tides ranging from <0.5 to 12 m; average breaker wave height from <0.5 m to ∼3 m; beach sediment from fine to medium sand, half of which is carbonate; and many of the ∼12 000 beach systems are embayed. Commencing in the mid-1970s this laboratory was utilized by members of the Coastal Studies Unit (CSU) leading to the development of beach models that encompass the full range of beach types and states that incorporate every Australian beach and most global beaches. This paper will review the development of these models, based initially on beach research on the micro-tidal, wave-dominated southeast coast; then expanding into both the higher wave energy environments of southern Australia and the higher tide range environments of northern Australia; culminating with an assessment of every beach system around the coast. The end result was the wave-dominated, tide-modified and tide-dominated beach models. [ABSTRACT FROM AUTHOR]

Duce, S., Vila-Concejo, A., Hamylton, S., Bruce, E., Webster, J. M, 2014. Spur and groove distribution, morphology and relationship to relative wave exposure, Southern Great Barrier Reef, Australia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 115-120, ISSN 0749-0208. Spur and groove features occur on the seaward reef slope of coral reefs around the world. They are believed to act as important natural breakwaters, regulating the hydrodynamic energy and nutrients received by reef platforms. They also represent one of the most diverse and productive zones of modern reefs. However, the formation processes and morphodynamics of spur and groove systems are poorly understood, particularly in the Great Barrier Reef (GBR). This paper constitutes the first broad scale analysis of spur and groove systems in the Capricorn Bunker Group (CBG) in the southern GBR. It uses remotely sensed imagery coupled with ground-truthed data to measure groove length at four reefs (Wreck, Heron, One Tree and Lady Elliot). A total of 2621 grooves were digitised across the four study reefs. Groove length was found to vary both between and within the study reefs. The maximum groove length was 536 m. Average groove length ranged from 93 m at Wreck Reef to 32 m at Heron Reef. This data was compared to relative wave exposure estimates derived from the fetch scenario at each reef. Strong positive correlation was found with groove length increasing as wave exposure increased. Groove length was highly spatially dependant and varied around the reef platforms according to the degree of wave exposure. The longest grooves were found on the most exposed, eastern sides of all reefs. These results provide valuable insight into spur and groove function, formation and likely response to future environmental changes in the CBG and further afield. [ABSTRACT FROM AUTHOR]

Abstract: Wave energy is increasingly being seen as an alternative source of low-emissions power particularly for Australia, as Australia has abundant wave resources. This paper, using the performance characteristics of wave energy converters (WEC), resource measurements along Australia''s southern coastline and global resource estimates, models projections of the future uptake of wave energy globally and in Australia. Globally, wave farms are projected to be installed up to a presumed maximum limit of 500 GW. In Australia there is more variability in the amount of wave farms installed, with differences across the different WEC. The outcome globally and in Australia depends on variations in the average power generated by the WEC and the carbon price path. In Australia, the majority of projected WEC installations are in the state of Victoria, which has relatively high demand and currently highly-emissions intensive sources of generation compared to states with better wave resources. When a dispatchable, or continuous power ability is added to wave energy''s output the uptake of wave energy increases in Australia, in those states with the best resources. When the amount of wave energy extractable in any region is increased or decreased it has a large effect on output in Victoria in particular, which generates power from wave energy up to 30% of the total extractable resource under the dispatchable power scenario. Wave energy has the potential to make a significant contribution to electricity generation globally and in Australia. This paper is part two of a series of papers, the first being . [Copyright &y& Elsevier]

This paper introduces a novel model for predicting the performance and conducting sensitivity analysis of design parameters in two-body point absorber wave energy converters. The key novelty lies in the examination of design parameter sensitivity and their interaction effects on performance. The model utilizes the response surface method (RSM) in conjunction with central composite design to establish analytical equations for efficiently predicting the resonance frequency and peak generated power of the two-body wave energy converters based on geometric parameters and wave height. This eliminates the need for complex analytical solutions and boundary element simulations. The accuracy and reliability of the RSM prediction models are validated through state-of-the-art numerical simulations and analysis of variance (ANOVA). Using these RSM prediction models, the study proceeds to design and optimize two-body point absorbers for locations along the coastlines of the six Australian states, focusing on two objectives: maximizing peak output power and maximizing the power-to-weight ratio at each location. By incorporating the second optimization target, it is observed that impressive power output with smaller device dimensions or a higher power-to-weight ratio can be achieved across all six Australian states. The developed response surface method prediction model is a versatile mathematical framework applicable to all two-body point absorber wave energy converters and can be adapted for optimizing other types of wave energy converters with expansive search spaces. Australia was selected as a case study due to its abundant wave energy density along its southern shorelines. Notably, no similar studies addressing these specific aspects have been reported in the literature, making this work the first of its kind. • The performance prediction models of two body wave energy converters have been developed from design parameters. • The prediction models are validated against numerical simulations and the analysis of variance (ANOVA). • The sensitivity of design parameters and their interactions has been analyzed and disclosed. • The optimal dimensions for the maximum power and maximum power to weight ratio are derived for all the Australian seas. [ABSTRACT FROM AUTHOR]

In the last decade, multiple studies focusing on national-scale assessments of the ocean wave energy resource in Australia identified the Southern Margin to be one of the most energetic areas worldwide suitable for the extraction of wave energy for electricity production. While several companies have deployed single unit devices, the next phase of development will most likely be the deployment of parks with dozens of units, introducing the risk of conflicts within the marine space. This paper presents a geo-spatial multi-criteria evaluation approach to identify optimal locations to deploy a wave energy farm while minimizing potential conflicts with other coastal and offshore users. The methodology presented is based around five major criteria: ocean wave climatology, nature of the seabed, distance to key infrastructure, environmental factors and potential conflict with other users such as shipping and fisheries. A case study is presented for an area off the south-east Australian coast using a total of 18 physical, environmental and socio-economic parameters. The spatial restrictions associated with environmental factors, wave climate, as well as conflict of use, resulted in an overall exclusion of 20% of the study area. Highly suitable areas identified ranged between 11 and 34% of the study area based on scenarios with varying criteria weighting. By spatially comparing different scenarios we identified persistence of a highly suitable area of 700 km 2 off the coast of Portland across all model domains investigated. We demonstrate the value of incorporation spatial information at the scale relevant to resource exploitation when examining multiple criteria for optimal site selection of Wave Energy Converters over broad geographic regions. [ABSTRACT FROM AUTHOR]

Offshore wind and wave power are abundant energy sources and could provide long term contributions to our future energy supply. The combined exploration of wind and wave power has been proposed as an effective way to mitigate the non-negligible power intermittency and variability of offshore renewables. However, the assessments of wind and wave resources have been developed separately in Australia, and the potential of diversified wind and wave power has not been studied systematically. This study investigates offshore wind and wave energy sources in multiple locations around the Australian coastline and their potentials for integration in terms of energy availability, power variability, coherence and correlation, and annual and seasonal variability over the last seven years. In addition, wind and wave mixed energy farms are studied using commercial wind turbine models and various wave energy converter prototype models. The energy availability, power smoothing effect, capacity factor and downtime of these mixed energy farms are also discussed. Moreover, this paper proposes an effective matrix for assessing the potential of hybrid energy farms in multiple sites in terms of power availability, power variability and combination performance and the sensitivity of selecting various wave energy converter (WEC) models is also investigated to provide a general guideline for future work. The regional comparative results indicate that the swell wave dominated sites in Western and Southern Australia present merits for combining wind and wave power, while wind–wave dominated regions, such as Eastern Australia, are not preferable for this diversified system. It can be found that power variability and downtime can be significantly reduced for the specific wind–wave capacity mix if a lower correlation or longer lag time exists between the two renewables. The results also illustrate that the combinations with different WEC systems present varying benefits in the different locations in Australia. • Wind and wave energy resources are assessed in Australian region. • A wave identification system is designed for hybrid exploration. • A matrix to assess the potential of combined energy farm is proposed. • Sensitivity of WEC selection to the combined energy farm is investigated. [ABSTRACT FROM AUTHOR]

Sandy beaches are unique environments composed of unconsolidated sediments that are constantly reshaped by the action of waves, tides, currents, and winds. The most seaward region of the dry beach, referred to as the beach face, is the primary interface between land and ocean and is of fundamental importance to coastal processes, including the dissipation and reflection of wave energy at the coast and the exchange of sediment between the land and sea. The slope of the beach face is a critical parameter in coastal geomorphology and coastal engineering, as it is needed to calculate the total elevation and excursion of wave run-up at the shoreline. However, datasets of the beach-face slopes along most of the world's coastlines remain unavailable. This study presents a new dataset of beach-face slopes for the Australian coastline derived from a novel remote sensing technique. The dataset covers 13 200 km of sandy coast and provides an estimate of the beach-face slope every 100 m alongshore accompanied by an easy-to-apply measure of the confidence of each slope estimate. The dataset offers a unique view of large-scale spatial variability in the beach-face slope and addresses the growing need for this information to predict coastal hazards around Australia. The beach-face slope dataset and relevant metadata are available at https://doi.org/10.5281/zenodo.5606216 (Vos et al., 2021). [ABSTRACT FROM AUTHOR]

Abstract: Wave energy is particularly abundant along the Australian southern coastline. Harvesting wave energy using a converter could provide a sustainable alternative for electricity generation for Australia. In this paper, the performance of three different types of wave energy converter (WEC) has been evaluated spatially for Australian coastal regions using Australian Renewable Energy Atlas wave energy data. It was found one of the WECs operated with a capacity factor greater than 54.3% for a large portion of the Tasmanian western coastline, while being located close to transmission infrastructure. The levelised cost of electricity (LCOE) for the WECs for these regions was in the order of $78/MWh. [Copyright &y& Elsevier]

Sriram, V., Sannasiraj, S.A., and Sundar, V., 2007. 2D Nonlinear wave body interaction using Semi-ALE. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 394 – 399. Gold Coast, Australia, ISSN 0749.0208 The present study aims at generating the fully nonlinear waves based on Finite Element method (FEM) used by SRIRAM et al. (2006). The author simulated the nonlinear waves based on structured mesh by regenerating the mesh at each and every time step using the Mixed Eulerian and Lagrangian (MEL) scheme. In this paper, it has been extended to unstructured mesh. The mesh is adapted at each and every time step by using the spring analogy method instead of regenerating at every time step which makes the above method called as Semi-Arbitary Lagrangian and Eulerian (Semi-ALE/SALE). The simulation has been carried out in a numerical wave tank (NWT) with a surface piercing rectangular object. For such a situation, the diffraction by a surface piercing object becomes relevant in connection to breakwater studies where the primary interest is wave reflection and wave transmission. Regular waves and solitary waves are generated from one end of the tank. The nonlinear wave reflection and transmission characteristics reveals that the transmission is less for regular waves, while in the case of solitary waves the reflected energy is very small and the transmission is more. [ABSTRACT FROM AUTHOR]

Abstract: The interactions between waves and morphology on shore platforms were investigated at four platforms located at Kaikoura Peninsula, New Zealand and the Otway coast, Victoria, Australia. Waves were measured over six tidal peaks of a spring tidal sequence at each site during a six month period (February 2007 – July 2007). This paper reports the results of an investigation into the research question: how are waves modified by platform morphology in a micro-tidal setting? Through the investigation of wave interactions on shore platforms it was found that complex hydrodynamic patterns formed on the shore platforms studied. Through direct measurement of waves on the platforms it was found that wave attenuation was not dependent on platform width, but rather influenced by platform gradient and depth of water on the platform. Spectral analysis was used to assess how wave energy was transformed across the platforms. At three of the four platforms investigated, energy gradients formed across the platform with wave energy recorded within the infragravity range. [Copyright &y& Elsevier]

Abstract: Australia is one of those countries that are considered rich and abundant in fossil fuel energy resources. It is important for Australia to regulate the use of conventional energy and attempt replacing these conventional energies with renewable energy (RE) resources. Renewable energy resources in Australia are widely categorised as solar energy, biomass, wave energy and wind energy. By increasing the utilisation of renewable energy resources the national contribution to world wide green house gases (GHG) emissions would be reduced, at the moment approximately 50% of Australia''s GHG emissions are contributed from electricity generation [Dicks, AL, Diniz da Costa, JC, Simpson A, McLellan B. Fuel cells, hydrogen and energy supply in Australia. Journal of Power Sources 2004;1:1–12] with a large proportion of the remaining emissions coming from transport and vehicular sectors. As Australia''s population, as well as that of the world, continues to grow and live increasingly energy dependant lives, the future of energy supply will grow. This paper investigates the potential of renewable resources in Australia at present and the magnitude of their present and future contributions to the national energy consumption. Conclusions will be drawn from the results of this investigative scan and recommendations will be proposed. [Copyright &y& Elsevier]

Abstract: The significant loss of wave energy due to seabed interaction in finite depths is a known effect and bottom friction terms are used in the wave models to account for this dissipation. In this paper, a new bottom-interaction function is tested by means of the SWAN model, based on measurements at two field sites, Lake George and Lakes Entrance, both in Australia. The function accounts for dependence of the friction on the formation process of bottom ripples and on the grain size of the sediment. The overall improvement of the model prediction both for the wave height and wave period is demonstrated. [Copyright &y& Elsevier]

One of the most encouraging sorts of renewable energy is ocean wave energy. In spite of a large number of investigations in this field during the last decade, wave energy technologies are recognised as neither mature nor broadly commercialised compared to other renewable energy technologies. In this paper, we develop and optimise Power Take-off (PTO) configurations of a well-known wave energy converter (WEC) called a point absorber. This WEC is a fully submerged buoy with three tethers, which was proposed and developed by Carnegie Clean Energy Company in Australia. Optimising the WEC's PTO parameters is a challenging engineering problem due to the high dimensionality and complexity of the search space. This research compares the performance of five state-of-the-art metaheuristics (including Covariance Matrix Adaptation Evolution Strategy, Gray Wolf optimiser, Harris Hawks optimisation, and Grasshopper Optimisation Algorithm) based on the real wave scenario in Sydney sea state. The experimental achievements show that the Multiverse optimisation (MVO) algorithm performs better than the other metaheuristics applied in this work. [ABSTRACT FROM AUTHOR]

Lekshmi G.R. and Sannasiraj S.A., 2007. Correlation of Breaking Wave Characteristics with Energy Dissipation. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 307 – 311. Gold Coast, Australia, ISSN 0749.0208 It is well accepted that wave breaking has a dominant role on the dynamics of upper layers of the ocean. While a lot has been learnt about wave breaking including the kinematics and dynamics of mixing, wave energy losses and ambient noise, there are many issues that are yet to be resolved These include the issue relating the energy dissipation with the wave spectral characteristics. In the present paper, the dependence of intensity of wave breaking on the energy dissipation has been studied. The simulation of wave breaking has been carried using constructive wave-wave interaction approach. The various intensities of breaking ranging from plunging to spilling have been generated in the controlled laboratory wave flume. The energy dissipation has been measured by tracing the water surface from pre-breaking to post-breaking zone. The results showed a noted difference in the amount of energy dissipation with the intensity of breaking. The study also reveals that wave breaking results in redistribution of spectral energy. Energy loss is found to be more towards the high frequency end. [ABSTRACT FROM AUTHOR]

An integrated study of sedimentological, sequence-stratigraphic and palaeodispersal analysis was applied to the Upper-Permian clastic sedimentary succession in the Northern Sydney Basin, Australia. The succession is subdivided into fifteen facies and three facies associations. The facies associations are further subdivided into eight sub-facies associations. The sedimentary evolution involves progradation from delta-front to delta-plain to fluvial depositional environments, with a significant increase in sediment grain size across the unconformable contact that separates the deltaic from the overlying fluvial system. In contrast to the delta front that is wave/storm- and/or river-influenced, the delta plain is significantly affected by tides, with the impact of tidal currents decreasing up-sequence in the delta plain. The general lack of wave-influenced sedimentary structures suggests low wave energy in the delta plain. The abrupt termination of the tidal impact in the fluvial realm relates to the steep topographic gradients and high sediment supply, which accompanied the uplift of the New England Orogen. The sequence-stratigraphic framework includes highstand (deltaic forest and topset) and lowstand (fluvial topset) systems tracts, separated by a subaerial unconformity. In contrast to most of the mud-rich modern counterparts, this is an example of a sand-rich tidally influenced deltaic system, developed adjacent to the source region. This investigation presents a depositional model for tidal successions in regions of tectonic uplift and confinement. [ABSTRACT FROM AUTHOR]

Saintilan, N.; Rogers, K.; Toms C. Stein, E.D., and Jacobs, D.K., 2016. Intermittent Estuaries: linking Hydro-geomorphic Context to Climate Change Resilience In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 133-137. Coconut Creek (Florida), ISSN 0749-0208. Intermittent estuaries are temporarily open to exchange with the open ocean, and the influence of their entrance opening regime on hydrological and ecological function has received considerable attention. Here we consider the influence of tectonic, climatic and geomorphic controls on the distribution of estuarine habitats by contrasting two settings: the south coasts of New South Wales, Australia, and California USA. The combination of tectonic uplift and semi-arid, variable hydrology in southern California provides a stronger sediment yield to estuaries than in the tectonically stable temperate setting of southern Australia. This reflects in a greater proportional area of intertidal vegetation and a higher elevation capital than encountered in SE Australia. The implications for estuary management in the context of sea-level rise and urbanization are discussed. [ABSTRACT FROM AUTHOR]

A process-based modelling study was carried out by applying a depth-averaged flow module (MIKE 21 HD) and a spectral wave model (MIKE 21 SW) to examine near-shore hydrodynamics of an estuarine beach located in an open estuary: Jimmy's Beach, Port Stephens, Australia. The models were calibrated and validated against recently acquired hydrodynamic data. Model results indicate a significant spatial variability in the near-shore wave parameters along the beach, depending on shoreline orientation; proximity to the mouth of the estuary and sheltering influences of adjacent headlands. Local bathymetry and shoreline orientation play a major role in determining the near-shore ocean wave characteristics at a site along the beach. The shoal previously thought to focus higher wave energy into the erosion spot, in contrast, results in wave energy dissipation. Locally generated waves by the prevailing westerly winds at Jimmy's Beach have low wave energy. Model results also suggest that the near-shore flow patterns are complex due to the presence of tidal eddies and variations in the near-shore wave field along the beach. Currents generated by local wind waves are subordinate to wind stress induced currents. These spatial differences reflect the complex configuration of estuarine shorelines, local topographic controls and variations in exposure to each of the forcing, and may contribute to a high level of beach mobility. [ABSTRACT FROM AUTHOR]

Offshore-detached structures are used to limit shoreline erosion, and to provide a safe haven for marine craft or bathers. Their function is to reduce the amount of wave energy in their lee, and to enhance sediment deposition at the shoreline. Planform shoreline changes in the vicinity of an offshore structure represent the integrated effect of natural shoreline variability, and engineering factors including sand nourishment, the formation of a shoreline salient, and a secondary “groyne effect” induced by a gradient in the alongshore transport. To quantitatively assess a structure’s performance, it is necessary to first distinguish the structure-induced effects from the pre-existing shoreline variability, and second to discriminate and quantify these differing modes of shoreline response. The easily applied technique “odd–even function analysis” can be used to discriminate the principal modes of shoreline behavior in the vicinity of offshore-detached structures, and to distinguish this induced response from naturally occurring shoreline variability. The successful application of the technique is illustrated to identify early trends in coastline adjustment in the lee of a new submerged reef structure at the Gold Coast, Australia. [ABSTRACT FROM AUTHOR]

Coastal evolution following the Holocene marine transgression in South Australia is examined under three contrasting coastal environments: the high-energy, microtidal southeast coast, and the Holocene barrier system of the Sir Richard and Younghusband peninsulas; the sandy deposits of the moderate-energy eastern Gulf St Vincent around the metropolitan Adelaide coastline; and the rapidly prograding sediments of the sheltered subtidal to supratidal gulf environments in the low-energy Upper Spencer Gulf. Although only the Upper Spencer Gulf case study provides detailed data on the Holocene sea level change, collectively, the three case studies illustrate differences in coastal evolution following the transgression, linked to factors such as regional variations in wave energy and wind regime, tidal range, and sediment availability. [ABSTRACT FROM AUTHOR]

Plecha, S., Sancho, F., Silva, P. and Dias, J.M., 2007. Representative waves for morphological simulations. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 995 – 999. Gold Coast, Australia, ISSN 0749.0208 In the present study, a set of representative waves is derived for the coast adjacent to the Ria de Aveiro, such that it is morphologically equivalent to the complete wave regime. Different schematising methodologies are presented, based on the principles of conservation of wave energy and equivalent longshore sediment transport capacity over the beach profile. Firstly, the sediment transport capacities due to the whole set of waves is computed and then various sets of representative waves are proposed based on the principles above. The most suitable set is selected by taking into account the dominant sediment transport processes at the selected site. The representative waves can be used to significantly reduce computational time in morphological models, by reducing the number of different sea states that characterise the annual wave climate. This simplified nearshore wave regime shall provide the wave effects into the sediment transport formulae and the hydrodynamical model. [ABSTRACT FROM AUTHOR]

Castelle, B., Turner, I.L., Ruessink, B.G., and Tomlinson, R.B., 2007. Impact of storms on beach erosion: Broadbeach (Gold Coast, Australia). Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 534 – 539. Gold Coast, Australia, ISSN 0749.0208 The 70 km long Queensland Gold Coast has been one of Australia's premier coastal holiday resort destinations for more than 40 years. Extreme events, particularly tropical cyclones approaching the area, can generate storm waves and surges which have caused widespread episodic damage to the local economy. Broadbeach, located on the Gold Coast, is a double-barred beach which is representative of most of the Gold Coast beaches. The present study aims to quantify Broadbeach response to storm events in order to assess the ability of this beach to withstand extreme events and to recover during periods of lower wave energy. From the 1st of March to the 10th of July, 2006, 35 accurate subaerial beach surveys were undertaken. ARGUS images were used to estimate the location of the nearshore bars. During this period, Broadbeach experienced three storm erosion events. Offshore buoy measurements are used to estimate wave conditions that occurred. The first storm (from the 2nd to the 6th of March) was a hybrid-cyclone which generated one of the most energetic wave conditions on the Gold Coast of the past 30 years, with measured offshore significant wave height reaching 5.3 m, and maximum wave height 10.7 m at the Gold Coast Seaway buoy. During the two other storm wave events, wave conditions were much less energetic than during the first storm, with significant wave heights ranging from 2 to 3 m. The early March extreme event resulted in a 48m3/m erosion of the subaerial beach and a 70 m seaward migration of the outer bar in just a few days. Abnormally high erosion rates were measured during both the second and third storm wave events. This may be explained by the outer bar decay following the early March extreme event, which did not provide any significant protection during the subsequent two storm wave events. The severe erosion measured in this study suggests that the current average beach width may be too narrow to withstand an extreme event succession similar to the conditions that occurred in 1967. [ABSTRACT FROM AUTHOR]