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Hilton, M.J.; Hatcher, S.V.; Wakes, S.J., and Konlechner, T.M., 2016. Flow Deflection and Deceleration Across a Simple Foredune. 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. 293-297. Coconut Creek (Florida), ISSN 0749-0208. There are few field observations of flow deflection across foredunes in a range of incident wind conditions. This study reports observations of (1) flow deflection across the seaward slope of a foredune during alongshore and oblique onshore incident winds; and (2) associated sand transport. We compare these with modelled results from Hesp et al. (2015). Sonic anemometers and sand traps were deployed along a transect across a simple foredune at St. Kilda Beach, Dunedin, New Zealand. Representative sections of each record were isolated for a range of incident wind directions, and for each section we determined flow deflection and relative change in wind velocity. The incident winds, observed on a 3m mast on the beach, ranged from 228° (35° oblique onshore) to 268° (5° oblique offshore) and 6 - 14 ms−1 mean wind speed (over 5-15 minute intervals). Gusts reached 28 ms−1. Onshore deflection varied between 19° and 23° for incident winds between 228° and 249° and 9-14 ms−1. Our results are only partly consistent with those of Hesp et al. (2015) for a similar foredune and similar strength winds. We also found deflection increases with increasing obliquity, the degree of deflection increases towards the crest, and that topographically-forced flow acceleration is strongly influenced by the angle of approach of the incident winds. In general, however, we measured more flow deflection than was modelled, including significant deflection for highly oblique winds. Relative wind velocity up the profile showed deceleration up-slope for all sections because the anemometers were placed within the vegetation. [ABSTRACT FROM AUTHOR]

Smyth, T.A.G. and Hesp, Patrick A., 2016. Numerical Modelling of Turbulent Flow Structures in a Blowout. 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. 328-332. Coconut Creek (Florida), ISSN 0749-0208. Blowouts are erosional landforms often formed on coastal sand dunes by the deflation of sediment by wind flow. Quantitative observations of wind flow within blowouts aided by the deployment of smoke-bombs, have noted that temporal and spatial variations in sediment transport occur with the presence of turbulent flow structures. However because of the discrete nature of anemometry data, the presence of flow structures has been difficult to quantify and our understanding remains largely conceptual. This study presents a detailed investigation of turbulent flow structures within a trough blowout using high resolution, three-dimensional computational fluid dynamic modelling. We show that when incident wind flow was parallel to the blowout axis, only limited flow steering took place but a well-defined near surface jet developed along the deflation basin. Conversely when incident wind flow was oblique to the axis of the blowout wind flow became steered along the axis of the blowout but no near surface jet was produced. During neither incident wind direction were corkscrew or helicoidal vortices produced. Our study concludes that the incident wind flow direction is critical to the effectiveness of a trough blowout as a corridor for wind-blown sediment. While wind from a range of oblique angles may be steered along the axis of blowout, its relative effectiveness of eroding and transporting sediment beyond the deflation basin and erosional walls is much reduced compared to axis parallel wind flows of the same incident wind speed. [ABSTRACT FROM AUTHOR]

Udo, K., 2016. Wind Turbulence Effects on Dune Sand Transport. 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. 333-337. Coconut Creek (Florida), ISSN 0749-0208. This study involved field experiment of instantaneous wind velocity, angle, and aeolian sand flux on a coastal dune and numerical simulation of spatial wind fields to analyze the effects of wind turbulence on aeolian sand transport. The field data demonstrate that horizontal turbulence intensity is approximated by a power equation of mean horizontal wind velocity and has a negative relationship with the mean wind velocity in various wind conditions. Horizontal turbulence intensity also has a negative relationship with the aeolian sand flux in various wind conditions, indicating the potential for introducing the turbulence intensity into the aeolian sand transport equation. The wind field simulated with a large eddy simulation (LES) model has reasonable wind characteristics consistent with ground elevation change measured in the field. However, results indicate accurate simulation of vertical wind velocity and both horizontal and vertical turbulence intensity is a great challenge compared to simulation of horizontal velocity. [ABSTRACT FROM AUTHOR]

Van der Weerd, A.J. and Wijnberg, K.M., 2016. Aeolian sediment flux derived from a natural sand trap. 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. 338-342. Coconut Creek (Florida), ISSN 0749-0208. In 2011, a mega-nourishment (the 'Sand Motor') was constructed along the Dutch Coast. Since it is a pilot project, its evolution is closely monitored. This paper presents first results on the temporal variation in aeolian sediment transport across the nourishment, based on (a) the rate of infill over a 4 year period of a small lake in the nourishment, (b) one year of semi-hourly collected video imagery and (c) four year of hourly-averaged wind data. It appeared that, apart from approximately the first half year, the infill occurred quite linearly over time at an average rate of about 1.9·104 m3/yr. The rate of infill in the first half year period was equivalent to an annual rate of 8.4·104 m3/yr. From the combination of video image data and wind data, it was derived that aeolian sand transport (by saltation) was only observed at hourly averaged wind speeds of at least 7 m/s. The monthly frequency of occurrence of above 7 m/s wind speed, was reasonably well correlated with monthly frequency of occurrence of aeolian transport (r=0.79). Nevertheless, when hourly wind speed exceeded 7 m/s, transport was only observed about 23% of the time, indicating the importance of supply limiting conditions for aeolian transport from the Sand Motor. [ABSTRACT FROM AUTHOR]

McCarroll, R.J.; Brander, R.W., and Turner, I.L., 2016. Bathymetric controls on very low frequency rip current motions. 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. 418-422. Coconut Creek (Florida), ISSN 0749-0208. Time-averaged mean rip currents are forced by persistent gradients in dissipation over shallow bars and deep rip channels. Time-variable horizontal surfzone eddies, at the ∼10 min or very low frequency (VLF) range, are forced by stochastic wave breaking injecting vortical energy into the surfzone. Previous observations note that deep channel rips have greater variability of velocity while shallow channel rips exhibit greater variability in trajectory, this suggests a continuum of flow states that at present are poorly understood. This paper investigates the degree of bathymetric control on VLF motions illustrating how VLF motions manifest on different morphologies. Three field sites are investigated using low-pass filtered: (i) mean velocity; (ii) variable eddy velocity; (iii) directional standard deviation; and (iv) instantaneous vorticity. A VLF flow-type parameter is introduced to differentiate flow regimes, based on degree of bathymetric control. A novel classification scheme is introduced: (i) strong bathymetric control, with high mean velocities and rip cell oscillation; (ii) moderate control, with high mean velocities and variable VLF trajectories; and (iii) weak control, with low mean velocities and mobile eddies. Level of bathymetric control may be related to channel orientation, in addition to relative depth. This study improves our understanding of rip flow variability over short times frames, with implications for sediment transport and beach safety. [ABSTRACT FROM AUTHOR]

Yang, Z.T.; Li, H.J.; Liang, B.C.; Lee, D.Y.; Pan, X.Y., and Xu, Y., 2016. Laboratory experiment on the bed load sediment transport over rippled bed. 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. 497-501. Coconut Creek (Florida), ISSN 0749-0208. Bed load sediment transport over rippled bedforms was investigated through a series of laboratory experiments with different combinations of bed slope, grain size, wave conditions and water level using a 2D wave flume. In addition to the measurement of surface waves and velocity, the water surface and bottom bed elevation were precisely monitored using video cameras to record the continuous processes of profile evolution, including ripple formation and migration under the assumption of longshore uniformity. The bed load sediment transport flux associated with ripple migration was then estimated. Numerical model SWASH was applied to provide representative forcing hydrodynamic parameters in the estimation of sediment flux where measurement data was scarce after proper validation. It was observed that ripples migrate with an average speed of 0.113 mm/s, and bed load sediment flux of 0.0061 kg m−1 s−1 respectively. Velocity skewness explains the highest correlation with ripple migration speed for all cases, while mean flow appears to be dominant in the coarser sand transport. Good agreement was found from comparisons of sediment transport flux between measurements derived from ripple migration and semi-empirical bed load transport formulations. [ABSTRACT FROM AUTHOR]

Abessolo Ondoa, G.; Almar, R.; Kestenare, E.; Bahini, A.; Houngue, G-H.; Jouanno, J.; Du Penhoat, Y.; Castelle, B.; Melet, A.; Meyssignac, B.; Anthony E.; Laibi, R.; Alory, G., and Ranasinghe R., 2016. Potential of video cameras in assessing event and seasonal coastline behaviour: a case study at Grand Popo, Benin (Gulf of Guinea). 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. 442-446. Coconut Creek (Florida), ISSN 0749-0208. In this study, we explore the potential of a nearshore video system to obtain a long-term estimation of coastal variables (shoreline, beach slope, sea level elevation and wave forcing) at Grand Popo beach, Benin, West Africa, from March 2013 to February 2015. We first present a validation of the video system with field data over a 10-day experiment conducted on Grand Popo beach in 2014. Secondly, 2-years daily and monthly timeseries are extracted and their variability is described as a function of regional forcing and climatic modes. All variables show large monthly variability. The longshore sediment transport estimated locally from video is in agreement with that derived from Era-Interim wave data re-analyses. Results show that the shoreline responds predominantly to tides at the event scale and to waves. Overall, this study suggests that video stations are efficient tools to monitor coastal processes over the long term, in complement with other conventional approaches. Although no clear conclusions can be drawn on inter-annual variability, the results show that it is important to build up extended coastal observation networks to address coastline changes over a wide range of scales. [ABSTRACT FROM AUTHOR]

Silva, R.; Mendoza, E., Mariño-Tapia, I.; Martínez, M.L., and Escalante, E. 2016. An artificial reef improves coastal protection and provides a base for coral recovery. 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. 467-471. Coconut Creek (Florida), ISSN 0749-0208. In 2007, Hurricane Dean caused extensive damage along the coast of Riviera Maya, exceptionally large mass of wind-transported sand was deposited on the beach front and gardens of the former NH Hotel in Puerto Morelos. Due to the chaotic sea state and the debris carried by the storm, the sand was contaminated with various pollutants, including terrigenous materials and biogenic matter. As an emergency measure, this sand was used to create an artificial dune in the grounds of the hotel. Given the high probability of future storms of such magnitude, it was decided that some form of sediment transport control was needed to protect the beach so an artificial reef was constructed 120 m off the shore. The structure, made of prefabricated concrete elements, has been effective as a coastal defense barrier and has also provided a habitat for several reef species. Five years after the placement of the structure the beach front, which had previously registered erosion problems, had returned to its natural cycle of summer growth and winter retreat and a large number of fish and coral species were using the habitat provided by the structure. However, the coral reef growing on this prefabricated structure was not long-lasting. The massive and persistent occurrence of Sargassum in 2015 brought oxygen depletion, reduced pH, an excess in nutrients and less water transparency on the Caribbean coast, leading to the decline of the reef habitat. Further studies are necessary to test whether reef species recolonize the prefabricated substrate. [ABSTRACT FROM AUTHOR]

Wang, J.; Liang, B.C.; Li, H.J.; Pan, X.Y.; Lee, D.Y., and Xu, Y., 2016. Swash motion driven by the bore and prediction of foreshore profile change. 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. 492-497. Coconut Creek (Florida), ISSN 0749-0208. The prediction of a swash zone bed profile resulting from complex hydrodynamic processes is a challenging task. A series of laboratory experiments at a 2D wave flume were carried out to investigate the evolution of foreshore profiles and sediment transport in the swash zone. The swash motions and the changes of foreshore profiles at the different stages of foreshore evolution were measured for 12 cases of different combinations of wave height, wave period and water level for two different initial beach slopes (1/5 and 1/15). From the evolution of foreshore profiles detected by side looking video cameras mounted to the glass wall of a 2D wave flume, the sediment transport rates were estimated precisely both in time and space using the 1-D sediment conservation equation. The characteristics of the instantaneous sediment flux of swash motion and feasibility of its prediction were discussed. The characteristics of the swash-averaged net sediment flux at different stages of beach evolution were investigated by detecting the detailed net flux at 2 minute intervals from the precise beach profile changes. Simple methods of prediction of sediment transport and foreshore profile change are discussed for swash motion driven by bores. [ABSTRACT FROM AUTHOR]

Osborne, P.D. and Forest, A., 2016. Sediment dynamics from coast to slope - Southern Canadian Beaufort Sea. 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. 537-541. Coconut Creek (Florida), ISSN 0749-0208. Profound changes in cross-shelf sediment fluxes are anticipated in coming decades in the southern Canadian Beaufort Sea where an accelerated increase in temperature could lead to large changes in Arctic river hydrology and coastal-marine geomorphologic processes. In the past decade sediment exported to the Beaufort Shelf has increased while sea level pressure has increased accelerating the Beaufort Gyre, strengthening coastal upwelling and expanding the Mackenzie River plume offshore. Sea-ice extent has decreased while storminess has increased increasing wave action, coastal downwelling, current surge and resuspension and transport on the shoreface and shelf. This paper investigates mechanisms, quantities and rates of sediment transport operating in this cold continental shelf-slope environment. Past studies from more than 2 decades of research are compared with recent measurements to develop improved estimates of sediment sources, pathways, fate and fluxes across the shelf and slope. In particular, we explore connections between data from a long term mooring observatory deployed over the continental shelf and slope during the ArcticNet-Industry Partnership (2009-2011) and Beaufort Regional Environmental Assessment (BREA 2011-2015) to those acquired in studies focusing on nearshore and shoreface. Sediment fluxes from the Mackenzie River and erosion of permafrost coasts are compared with outer shelf-slope measurements of settling particles and near-bottom fluxes. In turn, the role of atmospheric and cryospheric processes in forcing sediment transfer from coast to slope is investigated to assess system response to changing climate and evaluate implications for marine hydrocarbon resource development along the continental margin of the Arctic Ocean. [ABSTRACT FROM AUTHOR]

Collin, A., Etienne, S. and Jeanson, M., 2016. Three-dimensional structure of coral reef boulders transported by stormy waves using the very high resolution WorldView-2 satellite. 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. 572-576. Coconut Creek (Florida), ISSN 0749-0208. Coral reef boulders have been showed to reliably characterize the amount of wave energy related to cyclone, storm or tsunami events. The wave height and current velocity have been successfully explained by the variability in the boulder individual (morphology) and population (distribution) spatial patterns. Even if a single boulder may include a substantial amount of information, it may be highly challenging to characterize it given the access difficulty at the local and regional scales. Moreover, a boulder population is meaningful to robustly and continuously depict the energetic event that drove the sediment transportation. Recently the very high resolution satellite remote sensing has been demonstrated to help classify and measure the horizontal patterns (A- and B-axes) of the boulders at the submeter scale. Here we focus on the vertical dimension (C-axis) of the boulders. Based on boulder fieldwork measurements of the three axes and geographic locations, we constrain various spectral parameters of the remotely-sensed datasets (WorldView-2) to retrieve the three axes of the boulders, reaching a very satisfactory agreements (R2) of 0.95, 0.88 and 0.75, respectively. The innovative C extraction combined with the A and B information will allow geomorphologists to rapidly and extensively collect boulder data so that the underlying energy can be computed in a more expanded and accurate way, at the population scale. [ABSTRACT FROM AUTHOR]

Jeanson, M.; Dolique, F.; Sedrati, M.; Cohen, O.; Bertier, J.; Cavalin, A.; Charpentier, J, and Anthony E.J., 2016. Wave modification across a coral reef: Cap Chevalier, Martinique Island. 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. 582-586. Coconut Creek (Florida), ISSN 0749-0208. Waves exert a major influence on hydrodynamic processes and on sediment transport over shallow submerged coral reefs, as well as on reef-bound beaches. This study describes results from a field experiment conducted at Cape Chevalier in the southeast of Martinique Island (Lesser Antilles, French West Indies), and investigates spatial and temporal variations in wave characteristics across a microtidal coral reef and lagoon. Measurements of wave pressure fluctuations were obtained using three pressure sensors deployed across the reef from 28 to 30 November, 2011. Analysis of the measured data shows that wave characteristics were strongly influenced by water depth and reef geometry. Calculations of energy dissipation indicate an average energy reduction of 91.5% between the fore-reef and back-reef (86% at high tide and 98% at low tide). The mean energy reduction between the fore-reef and the beach was 95.5% (92% and 99% respectively at high and low tide). The incident waves measured at the fore-reef during the experiment were predominantly trade wind-generated with peak periods between 7 and 10 s. Depending on tidal elevation and water depth, back-reef waves were characterized by an energy distribution dominated by the peak 7-10 s gravity waves at high tide and by infragravity frequencies (>20 s) at low tide. Wave energy at the beach was dominated by infragravity frequencies during both high tide and low tide. Wave spectral analysis indicates, thus, significant filtering of peak period energy as waves traveled across the reef. [ABSTRACT FROM AUTHOR]

Zăinescu, I.F.; Vespremeanu-Stroe, A. and Tătui, F., 2016. Comparative spit dynamics. The case of deltaic river mouth spits. 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. 800-804. Coconut Creek (Florida), ISSN 0749-0208. This paper presents a comparison of evolution and dynamics of selected representative deltaic spits. Although recently receiving more attention, deltaic barrier spits still remain poorly understood in terms of long term evolution. Water, sediment and wave interactions at the river mouth are highly nonlinear such that hydrodynamic groin effects and sediment trapping mechanisms generate behaviours such as cyclic lobe progradation, as it is the case of some deltaic lobes, or conversely impose river mouth deflection when the wave influence becomes dominant. River mouth spits can be part of a prograding lobe ( e.g. Sacalin and the paleo-spits of the Danube Delta lobes, Ba Lat spits) or can be a sign of lobe abandonment due to lobe switching, geoengineering or extreme reduction in sediment supply ( e.g. La Banya, Ebro; Gracieuse, Rhone; Damietta, Nile). Human-induced reductions in river solid discharge have affected the majority of Mediterranean deltas and there is a wealth of other examples worldwide ( e.g. Krishna & Godawari deltas). Dependent on the wave climate and especially the wave direction, cuspate features, migrating sand waves or flying spits form at the downdrift side of lobes. Comparison of dynamics shows that spits experience high temporal (inter-decadal), spatial (alongshore) and inter-landform variability. Dynamics is complex, often resulting from different interrelating effects which importance in control can change over time. [ABSTRACT FROM AUTHOR]

Haghshenas, S.A.; Razavi A., A.; Bakhtiari, A., Jedari Attari, M., and Risk, M.J., 2016. Decadal Evolution of Mond River Delta, the Persian Gulf. 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. 805-809. Coconut Creek (Florida), ISSN 0749-0208. This paper studies the results of multi-disciplinary investigations on different features of evolution of the Mond River delta during the past five decades. Considering the high importance of Mond River and corresponding sediment discharge, physiography and watershed analysis of Mond River is investigated and sediment discharge from the river and its sand content are estimated in the first step. A numerical model has been utilized to investigate cases of flow and sediment transport behaviour in the coastal Mond area and annual rates of longshore sediment transport are estimated. The shoreline changes are investigated by analysing thirty four sets of aerial photos and satellite imagery taken between 1967 and 2014 to investigate decadal evolution of Mond River Delta during the past three decades. Eventually, numerical results are compared with field observations and comprehensive GIS based analysis of historic shoreline changes from aerial photos and satellite imagery. [ABSTRACT FROM AUTHOR]

Bezhenar R.; Jung K.T.; Maderich V., and Kim K.O., 2016. 3D numerical model of ecohydrodynamics for shallow waters. 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. 820-824. Coconut Creek (Florida), ISSN 0749-0208. A new modeling system for the calculation of ecohydrodynamics in shallow water bodies is developed. It consists of three interacting components: hydrodynamics, sediment transport and ecodynamics. The system takes into account changes in the light absorption in the water due to presence of phytoplankton and suspended sediments as well as in the bottom friction due to presence of bottom vegetation. The bottom friction in turn affects the currents and turbulence that govern the transport and dispersion of nutrients which are necessary for the growth of phytoplankton and bottom vegetation. The turbulent mixing influences the resuspension of sediments that changes absorption of light in the water, affecting the bottom vegetation growth. The influence of model feedbacks on the biochemical characteristics of shallow Lake Markermeer (the Netherlands) was studied. Results of modeling show good quantitative agreement with measurements of temperature, nutrients, and dissolved oxygen. Good qualitative agreement of bottom concentration of periphyton with measured field of bottom plants was also obtained. [ABSTRACT FROM AUTHOR]

Yoon, H.-D.; Cho, M., and Son, S.-Y., 2016. Investigation of wave breaking turbulence in morphodynamics modelling. 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. 942-946. Coconut Creek (Florida), ISSN 0749-0208. The effect of wave breaking turbulence on morphodynamics was investigated using Xbeach. To achieve this goal, the results from Xbeach simulation were compared with a large-scale laboratory experiment (CROSSTEX) and a numerical model (COBRAS) which is based on Reynolds-Averaged Navier-Stokes (RANS) equation. To incorporate the impact of wave breaking turbulence, a new near-bed turbulence estimation was suggested in addition to the existing turbulence options in Xbeach. Hydrodynamics results from Xbeach were generally in a good agreement with CROSSTEX and COBRAS. However, morphodynamics from Xbeach did not match well with CROSSTEX nor COBRAS, especially in the vicinity of a longshore bar. Most bathymetric changes occurred in the inner surf zone or swash zone, showing dune erosion. The possible causes of disagreement can be related to the limitation of the depth-averaged advection-convection equation used for sediment transport in Xbeach. Also, long wave motions dominates morphologic changes near the dune area. It is concluded that more investigation is still required to better simulate morphodynamics. [ABSTRACT FROM AUTHOR]

Pan, S. and Fairbairn, G., 2016. Impacts of Submerged Breakwaters on Nearshore Sediment Transport. 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. 1212 - 1216. Coconut Creek (Florida), ISSN 0749-0208. Submerged breakwaters have been increasingly popular as the coastal defence structures due to the advantages of the low construction costs and less visual intrusion. However, the impacts of the structures on nearshore sediment transport and beach morphology remain unclear. This paper presents the results of beach morphological changes affected by different submergence of a group of shore-parallel breakwaters under the combined wave and tide conditions from a depth-average process-based coastal morphological model - COAST2D. In this study, different breakwater crest levels are used in the model under both storm waves and tides based on the field measurements at the Elmer breakwater scheme site to investigate the impacts of the breakwater submergence on nearshore hydrodynamics and morphological changes. The results show that the fully submerged breakwaters produce more stable and balanced sediment loss/gain in the protected area, and yield more desirable formation of salients behind the breakwaters. The results also reveal the complex nearshore processes and morphological changes under the extreme waves for further study. [ABSTRACT FROM AUTHOR]

Kaoru, T. and Udo, K., 2016. Analysis of beach erosion because of the 2011 Tohoku earthquake and tsunami. 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. 1252 - 1256. Coconut Creek (Florida), ISSN 0749-0208. The 2011 Tohoku earthquake and tsunami caused the disappearance of beaches over a wide area because of inundation accompanying the land subsidence caused by the earthquake and because of tsunami erosion. This study aims to investigate the general characteristics of the 2011 earthquake and tsunami and identify the factors that caused beach damage. The study focuses on 74 beaches from Aomori Prefecture to Chiba Prefecture, including those where the damage was insignificant. Satellite and aerial image analyses demonstrated that the main factor in beach disappearance was not inundation following land subsidence caused by the earthquake but erosion because of sediment transport by the tsunami. There were many cases where a significant increase in the amount of beach retreat occurred when the tsunami overflowed a seawall, leading to the collapse of the seawall. It was also quantitatively confirmed that beach erosion could have been significantly reduced by the survival of the seawall. Three years after the 2011 tsunami and earthquake, the recovery rates differed between beaches on the Sanriku coast and those in other areas. The rate was ≤25% for many beaches on the Sanriku coast of the Rias terrain and ≥75% throughout the south of the Sendai plain. [ABSTRACT FROM AUTHOR]

Adityawan, M.B.; Tanaka, D., Mitobe, Y., and Widiyanto, W., 2016. A new computation method of bottom shear stress under tsunami waves, 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. 1247 - 1251. Coconut Creek (Florida), ISSN 0749-0208. The tsunami propagation in the river as well as sediment transport is highly affected by the bed stress beneath the wave. Unfortunately, most numerical models use an empirical method such as Manning's n, which was developed for steady flow. A new method in numerical modelling to assess bed stress and sediment transport induced by wave is developed based on the boundary layer approach. The boundary layer has a significant effect on the bed stress under unsteady flow. Bed stress under unsteady flow may exhibit phase shift and sign change to the free stream velocity. Recently, Simultaneous Coupling Method (SCM) was developed and verified by combining Shallow Water Equation (SWE) and k-ω model. The simplicity of SWE was maintained while k-ω model was used to assess the bed stress from the boundary layer. The velocity from SWE is assumed as the free stream velocity, which is used as the boundary condition for k-ω. The calculated bed stress from k-ω is used in SWE to obtain water depth and velocity. In this study, SCM is further developed by simulating a tsunami wave propagation around the Kitakami River mouth and verified using a laboratory experiment. The results show good comparison between the numerical and experimental. [ABSTRACT FROM AUTHOR]

Tõnisson, H.; Suursaar, Ü.; Alari, V.; Muru, M.; Rivis, R.; Kont, A.; and Viitak, M., 2016. Measurement and model simulations of hydrodynamic parameters, observations of coastal changes and experiments with indicator sediments to analyse the impact of storm St. Jude in October, 2013. 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. 1257 - 1261. Coconut Creek (Florida), ISSN 0749-0208. The aim of the study is to analyse the meteorological parameters, hydrodynamic conditions and coastal changes caused by a severe European storm referred to as St. Jude (Christian). It crossed the Baltic Sea on 27-29 October 2013. At Cape Kelba in the west Estonian archipelago, wave parameters were measured by RDCP and simulated by two wave models. Shoreline and topographic changes were recorded before and after the storm by RTK-GPS device. Simultaneous experiments with painted sediments were carried out to analyse sediment transport patterns and wave impact on the nearshore sea bed. It was the most significant storm in Estonia since 2007 with wind gusts up to 33 m/s and local storm surge height 1.5 m. The measured significant wave height reached 3.4 m at the 5.5 m deep point near the geomorphic study site. Modelling study indicated some wave-current-surge interaction effects. The distal section of the Kelba Spit elongated by about 12 m, but only minor changes were registered in the proximal part of the spit. The painted sediments placed on the sea bed at depths from 2-6 m were swept up to 20 m towards the shore. [ABSTRACT FROM AUTHOR]

Lim, H.S.; Chun, I.; Shim, J.S., and Kim, C.S., 2016. Wave-induced current simulated by wave-current coupled model in Haeundae. 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. 1392 - 1396. Coconut Creek (Florida), ISSN 0749-0208. The wave-induced current in Haeundae, at the southeastern end of the Korean Peninsula, is one of the main causes of beach erosion. The Korean government recently initiated a beach restoration project for Haeundae beach to protect the famous beach against wave-induced currents generated by waves during summer and winter. To mitigate beach erosion, two submerged breakwaters and a sand nourishment program were initiated in 2013. With the support of the Korean government, we have also started an R&D project to develop coastal erosion control technology in order to understand the processes of beach erosion by measuring sediment transport and hydrodynamics in Haeundae coastal waters, including the development of a numerical simulation method. The aim of this study is to understand the main processes of wave-induced currents that cause erosion at Haeundae beach by considering wave and tide interactions, using a wave-current coupled model compared with long-term observed wave and current data. We found that the cross-shore current during summer is mainly caused by the eddies produced by wave-induced currents generated by strong high waves during a Typhoon approaching from the SSW and S directions. During other seasons, a longshore current is produced by swell waves coming from the E and ESE directions. In comparisons with the measured data, we also found that the wave-induced current is well simulated by a wave-tide coupled model in Haeundae with a coastal environment of wave and tide interaction. [ABSTRACT FROM AUTHOR]

Sedigh, M.; Tomlinson, R.; Cartright, N., and Etemad-Shahidi, A., 2016. Morphological evolution of the Nerang River Entrance ebb-tidal delta. 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. 238-242. Coconut Creek (Florida), ISSN 0749-0208. The Nerang River entrance is a tidal inlet that connects the Pacific Ocean to the extensive Gold Coast estuarine system known as the Broadwater. Due to relatively fast northward migration of the inlet from 1920 to 1985 and the importance of having a safe navigable channel, the inlet was stabilized with two training walls in 1986. A sand bypassing system was implemented upstream with an average sand bypassing rate equal to the estimated net northward lonshore sediment transport in the area to prevent the formation of a bar across the entrance. However, historical analysis of survey data has shown an ongoing growth of the ebb-tidal delta at the river mouth. Thus, despite the sand bypassing system, costly dredging of the ebb-tidal delta is required to maintain safe navigation through the entrance. A number of studies have been undertaken to investigate sediment transport and hence morphological evolution. However, despite all the previous efforts, the cause of the ongoing ebb-tidal delta accretion is still not known with any degree of certainty. According to recent numerical modeling efforts, there is a considerable amount of longshore sediment transport leakage past the sand bypassing system, particularly during storm events. This paper will present a brief history of the dynamics of the Nerang River entrance since the early 1820s before reviewing historical sand volume analysis based on available survey data. An updated conceptual model will then be developed in order to better understand the morphological change in and around the Nerang River entrance area. [ABSTRACT FROM AUTHOR]

Dalledonne, G. L., and Mayerle, R., 2016. Modelling of storm impacts on the Shandong peninsula coast. This paper presents results of the investigation of the effect of storms on the morphodynamics of the Yantai coastal areas in the Shandong Peninsula, China. A two-dimensional depth integrated morphodynamic model for prediction of the morphological changes during extreme events was developed and applied. The model covers the entire Bohai Sea with increasing grid resolution towards the coastal areas near Yantai. Calibration and validation using tidal constituents and measured water levels and current velocities showed that the model is capable of predicting the hydrodynamics in good agreement with observations. Emphasis was given to the proper description of the spatial distribution of the seabed sediments and bed stratigraphy. The 20 most severe storms observed in the region from 2000 to 2013 were identified and reconstructed. Storm surges with increases in mean sea level of up to 1.7 m and significant wave heights up to 4.1 m were considered. The results showed that during the storms the levels of energy are mainly due to waves and tidal currents are only relevant at the capes and some channels and straits along the Shandong Peninsula. The resulting morphological changes indicated that although there is an overall loss of seabed material, particularly during the peak of the storms, the beaches near Yantai recover quite quickly just a few days after the extreme events. [ABSTRACT FROM AUTHOR]

Hein, C.J.; Fitzsimons, G.G., FitzGerald, D.M., and Fallon, A.R., 2016. Records of Migration and Ebb-Delta Breaching at Historic and Ancient Tidal Inlets along a River-Fed Paraglacial Barrier Island. 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. 228-232. Coconut Creek (Florida), ISSN 0749-0208. Tidal inlets link backbarrier environments to the coastal ocean and play a dominant role in both longshore and cross-shore sediment transport. Additionally, inlet-fill sequences comprise up to 50% of barrier lithosomes in wave-dominated settings. This study uses historic records to investigate centennial-scale cycles of inlet dynamics and barrier shoreline adjustment at Merrimack River Inlet (Plum Island, Gulf of Maine). Geophysical and sedimentological data reveal geometric and stratigraphic signatures of these recent changes, and allow for comparison to similar records preserved within a nearby 3600-year-old inlet-fill sequence. Driven by processes of longshore transport, spit elongation and ebb-delta breaching, the Merrimack River Inlet once actively migrated across a 2.5-km long section of Plum Island. An ebb-delta breaching event in the mid-1800s caused abandonment of the former inlet channel and the onshore welding of a large sand bar, which developed into the northern 1.5 km of the island. The inlet stabilized by jetties in the late 1800s. Ground-penetrating radar profiles and sediment cores across this former inlet channel capture the details of changes prior to breaching, including the seaward deflection of the otherwise southerly and landward-migrating channel, in response to onshore bar migration and welding. Similar details of inlet migration, bar welding, and ebb-delta breaching are observed stratigraphic records of an ancient inlet in central PI, located 7 km to the south. Comparison between the ancient and historical sequences provides clues to decipher the complex inlet dynamics preserved in the stratigraphic and sedimentologic record. [ABSTRACT FROM AUTHOR]

Cáceres, R.A.; Zyserman, J.A., and Perillo, G.M.E. 2016. Analysis of sedimentation problems at the entrance to Mar del Plata Harbor. Mar del Plata Harbor is an important center for the fishery industry in Argentina, and it has become an attractive site for international tourism because of the recent construction of a cruiser ship terminal. However, further development of this port halted several years ago because of the recurrent sedimentation problems in the access channel and basins. This site is characterized by advancement of the shoreline south of the harbor and a sandbank that develops across the access channel, while downdrift erosion and the associated shoreline retreat are due to partial blockage of the sediment transport caused by the harbor breakwaters. The mechanisms responsible for these sedimentation and erosion processes are examined using a coastal area morphological modeling system, MIKE 21/3 Coupled Model Flexible Mesh, developed by DHI. The morphological model was calibrated and validated against measured bathymetric changes. The model was then applied to a medium-term simulation with particular interest in the assessment of the effectiveness of re-establishing the design depth of the access channel through dredging. This morphological modeling allowed enhanced understanding of the main hydrodynamic and sedimentological processes occurring around the harbor entrance, as well as obtainment of information potentially useful for maintenance dredging. It was determined for the present hydrosedimentological conditions that the sandbank moves toward the access channel with high sedimentation rate. This means the navigation channel requires regular maintenance dredging or the construction of additional sediment retention interventions such as sediment traps, extension of the breakwater(s), etc. The efficiency of any intervention from the point of view of reducing sediment deposition at the harbor access should be verified before its implementation. In all cases, the northward transport would still be blocked, so artificial sediment bypass should be considered to protect the beaches north of the harbor. El puerto de Mar del Plata es un importante centro para la industria pesquera en Argentina y se ha convertido en un lugar atractivo para el turismo internacional debido a la reciente construcción de una terminal de cruceros. Sin embargo, el desarrollo de este puerto se encuentra detenido hace varios años debido a persistentes problemas de sedimentación en su canal de acceso y dársenas. Debido a la obstrucción parcial del transporte de sedimentos que provoca la escollera Sur del puerto, el área costera se caracteriza por el avance de la línea de costa aguas arriba, el desarrollo de un banco de arena a través del canal de acceso y significativos procesos de erosión en las playas ubicadas al Norte del puerto. Los mecanismos responsables de estos procesos fueron evaluados mediante el Sistema de Modelación Morfológica MIKE 21/3 de malla flexible desarrollado por la empresa DHI. El modelo morfológico fue calibrado y validado mediante relevamientos batimétricos realizados en el entorno del acceso portuario. El modelo fue aplicado con una simulación a mediano plazo (tres años), con especial interés en la evaluación de la eficacia que tendría una obra de dragado para restablecer la profundidad de diseño del canal. Esta modelación morfológica permitió una mayor comprensión de los principales procesos hidrodinámicos y sedimentológicos que ocurren alrededor de la entrada del puerto, así como la obtención de información potencialmente útil para el diseño de estructuras y la planificación del dragado de mantenimiento. Se determinó que para las presentes condiciones hidrosedimentológicas el banco de arena se mueve hacia el canal de acceso con altas tasas de sedimentación, por lo cual requiere un mantenimiento regular, o la construcción de obras complementarias tales como trampas de sedimentos, espigones, la extensión de la Escollera Sur, etc. Desde el punto de vista de la reducción de la sedimentación, la eficacia de cualquier intervención debe ser verificada antes de su aplicación. En todos los casos, el transporte de sedimentos siempre será bloqueado, con lo cual debe considerarse el bypass artificial de arena con el fin de proteger las playas ubicadas al norte del puerto. [ABSTRACT FROM AUTHOR]

Wang, A. M.; Wang, H. J.; Bi, N. S., and Wu, X., 2016. Sediment transport and dispersal pattern from the Bohai Sea to the Yellow Sea. Suspended sediment flux, dispersal patterns and its possible mechanisms in the Bohai Sea were investigated based on the observational data in May and November, 2012, data retrieved from MODIS imageries and the ocean current data from HYCOM. The sediment dispersal pattern and the annual net sediment flux presented evident seasonal variability. During wintertime, the prevailing strong northerly winds and the related high wave heights resuspended the sediment along the coast of the Huanghe Delta that was transported into the Laizhou Bay along its western coast and exported to the Bohai Strait through the eastern Laizhou Bay as enhanced by the coastal current. The wintertime contributed approximately 4.84 Mt of suspended sediment flux to the Yellow Sea, as higher than the flux in summertime by one order. In summertime, the less energetic environment together with the stratified water column was unfavorable to the sediment export to the Yellow Sea. As a result, the sediment delivered by the Huanghe to the sea in summertime mostly accumulated within the subaqueous delta, which acted as a primary source of sediment export to the Yellow Sea in wintertime. [ABSTRACT FROM AUTHOR]

Manson, G.K.; Davidson-Arnott, R.G.D., and Ollerhead, J., 2016. Attenuation of wave energy by nearshore sea ice: Prince Edward Island, Canada. Sea ice is widely held to be decreasing in coastal waters where it is known to be effective in attenuating wave energy. This process is critical for understanding nearshore sediment transport and coastal change in ice-infested waters. We explore the attenuation of waves shoaling in nearshore ice using a simple attenuation model, hydrodynamic modelling, field studies, and daily charts of sea ice. The attenuation model is drawn from studies in deep water and modified for shallow water using field measurements. In a simple but common configuration where ice lies in a band onshore and waves enter from open water, the theory that wave energy decays exponentially as waves enter ice appears to hold true in shallow and deep water. The wave energy density in ice relates to the incoming wave energy density, attenuation distance, and an attenuation coefficient related to ice concentration and floe diameter. Much of the variability in measurements is explained by the theory, but substantial uncertainty remains. Prediction potential might be improved with higher resolution wave measurements and modelling, consideration of the rebuilding of attenuated waves in partial ice cover, and separate treatment of new ice. The adapted semiempirical theory is likely generally applicable to ice-infested coastal waters, but field studies in particular environments will be required to calibrate attenuation. [ABSTRACT FROM AUTHOR]

Shaw, C.E. and Benson, L., 2015. Possible tsunami deposits on the Caribbean coast of the Yucatán peninsula. The western Caribbean Basin is notable for its tectonic stability. It has experienced no historical earthquakes or the tsunami that sometimes accompany them. This paper describes a single, wedge-shaped, boulder-covered, coastal berm on the Yucatán coast of México that stretches unbroken for 50 km across a coastal segment characterized by rocky headlands that alternate with crescent beaches. The remainder of the 350 km of Yucatán coast consists mostly of mangrove that extends 1 to 30 km inland, often behind long, sandy beaches. On the headlands, the surface of the berm is densely paved with boulders-large boulders on its seaward face and smaller boulders and cobbles on its gently sloping inland surface. The top of the berm reaches an elevation >4 m, above the reach of all but the largest modern storm waves. Berm sediments on the headlands consist of two distinct layers of unbedded coarse sand with numerous randomly distributed boulders and cobbles in the lower layer and a crudely textured gravel and sand layer above. At first glance the two layers appear to be separated by 20 cm of white sand above a thin, discontinuous zone of dark, greyish sand that contains isolated balls and smears of black organic material, apparently derived from a soil, or possibly leaf litter. The berm and its associated boulders track the modern coastal morphology in precise detail as it follows the form of modern headlands, bays, and transcoastal channels, indicating that deposition took place after development of the present coast. The berm sediments record two or three large waves, depending on whether the wave that deposited the boulder pavement is regarded as part of the second wave or as a separate wave. Radiocarbon dating indicates that at least one wave struck the coast approximately 1500 years before present. Minimum wave run-up exceeds 4 m above present sea level, and inland inundation reached 400 m along bays and transcoastal channels. The position and elevation of the berm, its lack of well-developed internal bedding, the paving of the berm surface by thousands of boulders, and its 400-m extent inland along channels and bays are features commonly associated with tsunami. However, some recent studies conclude that all of the features listed also can be produced by mega-hurricanes. Placed in the context of our literature search of the recent history of hurricanes and tsunami in the Caribbean Basin, we conclude that the single berm on the Yucatán coast represents an anomalous event for this area and that the berm sediments bear a strong similarity to descriptions of sediments from some historical tsunami and are unlike sedimentary features associated with historical hurricanes. [ABSTRACT FROM AUTHOR]

Shi, B.; Wang, Y.P.; Yang, Y.; Li, M.; Li, P.; Ni, W., and Gao, J., 2015. Determination of critical shear stresses for erosion and deposition based on in situ measurements of currents and waves over an intertidal mudflat. Accurate determination of the critical shear stress associated with the erosion and deposition of sediments is an important component of numerical models used to predict and quantify sediment behavior and transport across intertidal flats. In this study, water depth, wave parameters, near-bed turbulent velocity, suspended sediment concentration (SSC), and intratidal bed-level changes were measured to determine the erosion ( τce) and deposition ( τcd) thresholds of sediments on an intertidal mudflat at Jiangsu, China. Based on integrated field measurements of bed-level changes and hydrodynamics, the bed shear stresses of currents ( τc), waves ( τw), and combined current-wave action ( τcw) were calculated, and the critical shear stress required for erosion ( τce = 0.14 N/m2) and deposition ( τcd = 0.08 N/m2) of these sediments was determined. Both values are in agreement with an estimate of τce (0.13 N/m2) that was based on water content and τcd values calculated by previous works, indicating that the value of τce estimated for these sediments is controlled primarily by the water content of the sediments. During field measurements, deposition occurred ( τcw < τcd) when current action exceeded wave energy ( τc > τw) during calm weather, whereas erosion occurred ( τcw > τce) when wave action increased dramatically during rough weather. Our field data showed that high current velocities lead to low τc, possibly because high SSC reduced the drag coefficient, which is variable during a tide, and further caused low τc under high current velocities. Additionally, bedforms characteristic of intertidal mudflat ( e.g., gullies, small creeks, ripples, or saltmarsh) has a significant influence on the drag coefficient of the bed. These observations suggest that the bed level responds strongly to changing hydrodynamic conditions, and also that waves are of great importance to erosion. This study demonstrates that the in situ determination of the parameters that control erosion and deposition is a useful approach to obtaining values of τce and τcd, which provide the basis for a mechanistic understanding of the morphological evolution and development of predictive sediment transport and erodibility models. [ABSTRACT FROM AUTHOR]

Medellín, G.; Mariño-Tapia, I., and Euán-Ávila, J., 2015. The influence of a seawall on postnourishment evolution in a sea-breeze-dominated microtidal beach. The postnourishment beach evolution is evaluated on a sea-breeze-dominated microtidal beach in Yucatan (Mexico). The study area has experienced severe beach erosion due to both alongshore sediment-transport gradients during calm conditions and offshore sediment transport during extreme wave events. Therefore, a shoreline restoration program, including beach nourishment and the removal of groynes, was carried out in 2002. Bimonthly subaerial/intertidal beach profiles measured during 7 years (2002-09), in front of a seawall and at an adjacent beach (nonwalled), are employed to analyze the beach nourishment evolution. Empirical orthogonal function (EOF) analysis of the shoreline time series is performed using the data extracted from the 50 field surveys. The temporal evolution of the EOF analysis shows the following: (1) an abrupt increase in beach width due to nourishment at the study site at the beginning of 2003, (2) followed by a sustained increase (from 2004 to 2007) owing to the sediment advection from a massive beach fill performed up-drift of the study area, and (3) a decrease in beach width from 2007 until the end of the study period. Moreover, the mean profile-volume change is estimated separately for walled and nonwalled beach sections. The nonwalled profiles results are consistent with the temporal evolution described by the EOF analysis. On the other hand, walled beach profiles show a net volume loss from 2002 to 2007, remaining stable during the following 3 years. Consistent with previous studies, seasonal variability of sand volume was found to be greater in front of the seawall with respect to the nonwalled section. Nevertheless, the erosional/despositional rates in the two sections show opposite trends during mean (sea-breeze) wave conditions, being more important in the subaerial beach profiles. The latter implies that swash-zone sediment transport represents an important contribution to the total sediment budget in the study area; hence, seawalls can significantly modify coastal dynamics in sea-breeze-dominated environments. [ABSTRACT FROM AUTHOR]

Zhang, H.; Yang, H., and Jeng, D.-S., 2015. Contaminant transport in capped deformable partially saturated sediments. Contaminated sediment tends to consolidate in response to the loading imposed by an overlying cap layer. The form of transient solute advection through sediments and caps is consequently changed. Therefore, the contaminant discharge into the overlying water is expected to increase and the effectiveness of the in situ capping system will be strongly affected. In this study, a one-dimensional sediment-cap model coupling consolidation and advection-dispersion equation was established. A simplified model was proposed through the sensitivity analysis, and then a parametric study was conducted. Numerical examples concluded that the absorption, degree of sediment saturation, cap thickness, and sediment depth significantly affect the contaminant discharge from the top of the cap. Therefore, these parameters should be considered carefully during cap design. [ABSTRACT FROM AUTHOR]

Hale, R.; Jacques, R.O., and Tolhurst, T.J., 2015. Cryogenic defaunation of sediments in the field. Ecological experiments designed to examine the effects of macrofaunal biodiversity may require the defaunation of intertidal sediments; however, many current techniques result in physical disruption of the sediments. A method of field-based cryogenic defaunation, which has advantages over existing methodologies, was developed to provide macrofaunal defaunation of intertidal cohesive sediment with minimum physical disruption. A sediment core transport apparatus and polystyrene freezing chamber allow the use of liquid nitrogen for effective freezing of a whole core of sediment in the field. Freezing the whole core intact minimises physical disturbance to the sediment and retains the topography of the sediment surface and sediment grain distribution with minimal effect on sediment properties and the microphytobenthos. This method is effective at removing up to 97% of infaunal macrofauna abundance from the sediment. Hediste diversicolor were found to be the most resistant species, with a 71% reduction in species abundance. Sediments defaunated in this way can be replaced in situ or removed to the laboratory for experimentation. This method of cryogenic defaunation would also be suitable for the defaunation of other marine or terrestrial sediments. [ABSTRACT FROM AUTHOR]

Gandara-Martins, A.L.; Borzone, C.A.; Guilherme, P.D.B., and Vieira, J.V., 2015. Spatial effects of a washout on sandy beach macrofauna zonation and abundance. Washouts have an important function in backshore zone drainage and remobilization of sediments for littoral transport. It is known that they can change beach morphology along its course, but their effects on the macrofauna community still represent a gap in knowledge of sandy beach ecology. Based on previous studies developed in larger systems, such as channels and estuaries, we aimed to assess how the macrofauna community responds to the presence of a permanent sandy beach washout. The study was carried out at an exposed sandy beach in southern Brazil, where six cross-cut transects 0, 3, 9, 27, 81, and 243 m in distance from the washout were defined. Biological and environmental samples were taken at nine levels along each transect. As expected, beach morphology and water table salinity were affected by the washout, resulting in changes in the macrofauna zonation pattern and community descriptors. The isopods Tholozodium rhombofrontalis and Excirolana armata were dominant at all levels close to the washout, where polychaetes, amphipods, and mollusks were almost absent. Macrofauna reached the typical zonation pattern for local, nearby beaches only at distant transects. A good correlation between biological and environmental variables was observed. These results indicate that washouts can modify the macrofauna community at a small spatial scale, and only species adapted to a high range of variation in salinity (euryhalines) with a high mobility can live in substantial numbers close to and within these freshwater streams. [ABSTRACT FROM AUTHOR]

Dai, H.; Ye, M., and Niedoroda, A.W., 2015. A model for simulating barrier island geomorphologic responses to future storm and sea-level rise impacts. This paper presents the Barrier Island Profile (BIP) model, a new computer code developed to simulate barrier island morphological evolution over periods ranging between years and decades under the impacts of accelerated sea-level rise and long-term changes in the storm climate. The BIP model is a multiline model that represents the time-averaged dynamics of major barrier island features from front beach to backshore. Unique contributions of BIP to coastal modeling include a dynamic linking of interacting barrier island features and consideration of both future sea-level rise and storm climate impacts. The BIP model has the built-in capability of conducting Monte Carlo (MC) simulations to quantify predictive uncertainty caused by uncertainty in sea-level rise scenarios and storm parameters. For a series of barrier island cross-sections derived from the characteristics of Santa Rosa Island, Florida, BIP was used to evaluate their responses to random storm events and five potential accelerated rates of sea-level rise projected over a century. The MC simulations using BIP provide multiple realizations of possible barrier island morphologic responses and their statistics, such as mean and variance. The modeling results demonstrate that BIP is capable of simulating realistic patterns of barrier island profile evolution over the span of a century using relatively simple representations of time- and space-averaged processes with consideration of uncertainty of future climate impacts. [ABSTRACT FROM AUTHOR]

Yang, Z.; Chen, D.; Huang, D., and Yang, Y., 2019. Prediction of coastal evolution in Puerto Cabello, Venezuela. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 16–21. Coconut Creek (Florida), ISSN 0749-0208. Coasts vary in their composition and the physical processes that affect them. However, their nature and behavior have similarities. Presently, the majority of coasts worldwide are eroding. The rapidly increasing threat of global warming and the resulting rise in sea level can accelerate coastal erosion. The nearly 2 km coastline in the port city of Puerto Cabello in Venezuela, to the west of the island Goaigoaza, was taken as a case study. The long-term state of the beach was assessed by considering the credits and debits of sand that pass through the coastal system. In the study, the net longshore sediment transport rate in the west of the salient was westward and Qin < Qout, denoting that beach erosion will occur in this particular area. Through field investigations and theoretical analysis, it can be preliminarily concluded that the beaches in the study area are slightly eroded. However, a long-term study on the current profile is essential to arrive at a decisive conclusion. [ABSTRACT FROM AUTHOR]

Azhikodan, G. and Yokoyama, K., 2015. Temporal and spatial variation of mixing and movement of suspended sediment in the macrotidal Chikugo River estuary. The effect of mixing on the movement of the estuarine turbidity maximum (ETM) was examined in the highly turbid Chikugo River estuary, Japan, in consideration of four significant issues: semidiurnal and semilunar tidal variations, spatial distribution, and synchronism of data acquisition. Vertical profiles of salinity and turbidity were measured for 2 weeks at 1 km intervals from the river mouth (0 km) to 17 km upstream, with a short duration for every cruise. Spring-neap transition and the spatial variation of mixing, and suspended sediment concentration (SSC) was found during the semilunar tidal cycle. The estuary gradually changed from a vertically well-mixed condition during spring tide to a stratified condition during the neap tide via a partially mixed condition during the intermediate half tides. The relationship between the flow ratio and the SSC showed that ETM growth was dominated by both tidal forcing and freshwater flow. SSC was high when the salinity was 0.5 practical salinity units (psu) in the upper estuary and 10 psu in the lower estuary. For the same mixing strength (MS), SSC in the lower estuary was greater than that in the upper estuary. Based on flow ratio, salinity, and MS, the occurrence of the ETM and its development at the macrotidal estuary was a consequence of three processes: bed-sediment erosion by seawater in the lower estuary, sediment transport in the estuarine channel by the tidal current and freshwater flow, and sediment accumulation at the salinity front in the upper estuary. [ABSTRACT FROM AUTHOR]

Li, L.; Wu, H.; Liu, J. T., and Zhu, J., 2015. Sediment transport induced by the advection of a moving salt wedge in the Changjiang Estuary. This study focused on the intratidal variations of suspended sediment concentration (SSC) and residual sediment transport near a moving salt wedge in the Changjiang Estuary. The stratification was controlled by the advection of the salt wedge and was strengthened during the flood tide and weakened during the ebb tide. This phenomenon is the opposite of systems that are dominated by tidal straining of salinity, which diminishes the stratification during the flood tide and enhances it during the ebb tide. The enhanced stratification during the flood tide restricts turbulent mixing; hence, the resuspended sediment is concentrated below the pycnocline. Because of the stronger turbulent mixing during the ebb tide, the suspended sediment can be elevated to the surface, decreasing the near-bottom SSC. Such tidal asymmetries of mixing and near-bottom SSC cause the net sediment flux to be directed landward in the lower layers after a tidal cycle. [ABSTRACT FROM AUTHOR]

Saravanan, S. and Chandrasekar, N., 2015. Wave refraction pattern and littoral sediment transport along the SE Tamilnadu coast, India. The objective of the paper is to understand the wave refraction pattern and littoral sediment transport along the SE coast of India. There are areas of erosion and accretion observed along the coastal stretch that depend primarily the direction of wave approach, the wave period, and the wave refraction pattern. In the nearshore zone of the study area, the movement of sand alongshore is due to the action of waves and currents. Wave refraction is an important process responsible for effecting changes in coastal configuration. Based on this study, the wave convergent and divergent zones are identified with reference to wave refraction. Longshore sediment transport is higher in the northerly direction than in the southerly direction. The present study of littoral sediment transport implies that the beaches of Kanyakumari, Navaladi, and Ovari have greater transport rates. [ABSTRACT FROM AUTHOR]

Little, D.I. and Bullimore, B., 2015. Discussion of: McLaren, P., 2014. Sediment trend analysis (STA®): Kinematic vs. dynamic modeling. Journal of Coastal Research 30(3), 429-437. The first sediment trend analysis (STA) in the United Kingdom was of Milford Haven Waterway, in 1987. Its findings and recommendations have since been tested intensively in terms of physical, chemical, and biological field data and have not been found wanting in the high profile of a major oil and gas port located in an internationally important conservation area. This discussion summarizes a wide range of multidisciplinary evidence that supports the STA method and conclusions. The STA kinematic approach has helped to generate falsifiable hypotheses for further research of the coastal and estuarine processes in the waterway. The results also provide a robust framework for monitoring and managing its environment. The approach could be used in combination with dynamic modeling but without necessarily waiting on a detailed understanding of all the variables. This simple philosophy is illustrated by McLaren's timely reminder of two historic debates in the Earth sciences: the age of the Earth and continental drift. Some additional thoughts on these classic struggles are provided. [ABSTRACT FROM AUTHOR]

Barboza, C.D.N.; Paes, E.T.; Jandre, K.A., and Marques, Jr., A.N., 2014. Concentrations and fluxes of nutrients and suspended organic matter in a tropical estuarine system: The Tinharé-Boipeba Islands Archipelago (Baixo Sul Baiano, Brazil). Variations in the concentrations and fluxes of nutrients and suspended organic matter were examined during tidal cycles in four sectors (Barra dos Carvalhos, Barra de Boipeba, Cairu, and Galeão) of the estuarine system of the Tinharé-Boipeba Islands Archipelago (ESTBIA) on the northeastern Brazilian coast. In this study, we obtained new data by sampling and also used data from the literature (for Galeão) to estimate the exchange of nutrients between the estuary and the adjacent sea and to evaluate the factors that control these fluxes. It was observed that the factors that most influenced the nutrient fluxes in the estuarine system were the variations in the tidal prism and in the fluviometric regime. Moreover, the highest concentrations of dissolved inorganic nutrients occurred during the neap tide cycle, whereas the highest concentrations of particulates were found in the spring cycle. Organic carbon was transported in greater amounts in the dissolved form than in the particulate form, whereas nitrogen occurred predominantly in the organic form. The C : N and C : P ratios of the particulate organic material were typically high, showing a certain degree of seasonality related to the level of flooding of the mangroves. The nutrient fluxes transported in each sector showed the following tendency: Galeão ≥ Cairu >> Barra dos Carvalhos >> Barra de Boipeba. The net budgets for water and nutrients obtained for Galeão always reflected export from the estuary. In the other regions, particulate organic carbon, NO , NO , and NH were also exported from the estuary, whereas the remaining nutrients were exported during the neap tide cycle and imported during the spring cycle. [ABSTRACT FROM AUTHOR]

Kaiser, M.F., 2014. Disturbance of hydrodynamic regime in the Mediterranean coastal zone of Egypt. Engineering structures induce variations in the physical parameters of incident waves approaching coastlines, affecting the rate of longshore sediment transport and the patterns of shoreline change. Landsat Thematic Mapper images acquired from 1990 to 2005 and field measurements were utilized to perform mathematical modeling along Mediterranean coastal zones in Egypt. The K1 transport coefficient values used to calibrate the models ranged from 0.05 to 0.9. To accommodate changes in the physical conditions, a second calibration was required. The K1 transport coefficient values determined by the second calibration ranged from 0.1 to 0.7. These results indicate that the hydrodynamic regime along the Nile Delta coastal zones during 1995-2000 (verification) and 2000-2005 (second calibration) was disturbed by the effect of engineering works. Therefore, the calibration parameters used in simulations before 1995 are not appropriate for use after 1995. These findings demonstrate how the physical parameters of waves and currents are disturbed after some protective structures are modified. [ABSTRACT FROM AUTHOR]

Kim, K.H. and Shim, K.T., 2014. A field investigation of waves and wave-induced currents at the Youngrang Coast of the Republic of Korea. An accurate identification of the root cause of beach erosion should be taken in the precedence over designing reliable countermeasures. This study reviews the characteristics of the wave-induced currents by using the observation results on wave and current. The observed patterns were taken from comprehensive observation results which studied characteristics of wave and wave induced current as well as suspended load and bed load. The observations were conducted at the Youngrang Coast in the east coast of Korea. Based on the field observation results, Youngrang Coast has intermittently shown the occurrence of high waves due to winter monsoons. Affected by the high waves, the wave-induced currents have shown to exist inside the wave-breaking zone with a current velocity of 0.5-1 m/s. Such strong wave-induced currents are considered to be acting the main source of winter longshore sediment transport and beach erosion. [ABSTRACT FROM AUTHOR]

Lim, H.S.; Kim, C.S.; Lee, H.J.; Shim, J.S.; Kim, S.J; Park, K.S., and Chun, I., 2014. Variability of residual currents and waves in Haeundae using long-term observed AWAC data. The Haeundae in the southeastern Korean Peninsula is a famous beach which is one of the most popular tourist attractions of Korea in summer. It is about 1.6 km long and 40 m wide facing the southeastern sea of Korea and Korea Strait. During strong winds in winter and severe typhoons in summer, the beach is significantly eroded by waves and nearshore currents in the surf zone. The intensive coastal developments during last 30 years have caused substantial beach erosion and bathymetric changes in the nearshore area, despite various beach restoration projects, including beach nourishments. Recently, the government decided to construct two submerged breakwaters near both ends of the beach to enhance the preservation potential of the beach replenishments. We estimated the seasonal variations in residual currents from one-year flow measurements using the Acoustic Wave and Current (AWAC) meter, at two locations of Haeundae at approximately 15 m and 22 m in depths. Short-term flows were measured in the surf zone during summer and winter. The moving average method was applied fortnightly to estimate the residual currents. In addition, waves measured with the AWAC were analyzed to characterize seasonal variations in the beach environment of Haeundae. The observed residual currents were well matched with the simulated counterpart from a wave and current coupled model. These simulated nearshore currents appear well correlated with seasonal variations in beach erosion and accumulation. The wave and current data were also used to validate an operational coastal modeling system for the prediction of hydrodynamics. These observations will be incorporated in simulations of sediment transport in Haeundae coastal waters for developing coastal erosion control system. [ABSTRACT FROM AUTHOR]

Kim, H.; Jin, J.Y.; Jang, C.; Yoo, H.J., and Hwang, D.H., 2014. Simulation of seasonal bathymetric change at Haeundae Beach with two representative wave settings. Long-term shoreline position of Haeundae Beach has been quite stable notwithstanding seasonal oscillatory movement. Bathymetry around Haeundae Beach was surveyed on 7 August 2007 and 12 November 2007 by using an echo-sounder, while wave, tide, and tidal current were measured between the two survey days, so that bathymetric change at Haeundae Beach was obtained from the two surveys. According to the surveys the east part of the beach was eroded, and the west part of the beach was accreted. Measured waves from SSE, SE, ESE, E during the period were stronger than measured waves from S, SSW, SW, WSW. A numerical model system CST3D was adopted to reproduce the bathymetric change at Haeundae Beach during the period. Two representative wave settings are chosen for the period as a minimum number to represent the time-series of wave record, based on equivalent sediment flux concept contained in the CERC formula. Wave field, wave-induced force field, wave-induced current field, sediment transport field, and bathymetric change are computed from individual modules, SWAN, WIF, FLOW, SED in CST3D, respectively. Computed bathymetric change agrees reasonably well with measured one. It is believed that selection of two representative wave settings is useful for simulation of seasonal bathymetric change for fairly straight morphology like Haeundae. CST3D is thought to effectively describe overall seasonal sediment transport pattern and consequent bathymetric change at Haeundae Beach. [ABSTRACT FROM AUTHOR]

Martínez, R.; Silva, R., and Mendoza, E., 2014. Identification of coastal erosion causes in Matanchén Bay, San Blas, Nayarit, Mexico. This work presents an analysis of the erosion processes in Matanchén Bay based on the available historical records; the possible causes were identified and discussed. The bay is located on the Pacific coast of Nayarit state, Mexico; its northern tip is a highly dynamic system that has undergone intense morphological modifications over the last 80 years. At the beginning of the 1940s an unexplained growth in the beach at the northern tip of the bay was observed, while 40 years later, and up to date, erosion processes began adversely affecting small businesses in the area. The primary causes of the erosion are the anthropogenic modifications in the bay and its surroundings, which include the construction of a hydroelectric dam system, new transport infrastructure, tourist facilities, a harbor and several dredging works in the existing port. In this paper the evolution of the coastline at Matanchén Bay and its surroundings is analyzed for the first time and the actual coastline is compared to that predicted under the assumption that no countermeasures against the erosion are adopted. [ABSTRACT FROM AUTHOR]

Alonso, R.; López, G.; Mosquera, R.; Solari, S., and Teixeira, L., 2014. Coastal erosion in Balneario Solís, Uruguay. Balneario Solís is a seaside resort located in Uruguay, on the northern coast of the outer Río de la Plata estuary. Its main beach has suffered an erosion process that has affected the cliffs, producing a retreat of approximately 35 m between 1980 and 2001. Nowadays, some buildings are at risk of collapse and tourism has been seriously affected. Aerial photo analysis shows a temporal coincidence between the beginning of the erosion process and a change in the growing direction of a sandspit located next to the beach. Assuming the later as a geomorphologic indicator of the net littoral transport, the erosion process was linked to littoral transport change. No human factors were clearly identified to explain this change. Therefore, two hypotheses were formulated and analyzed: climate variability and natural modifications of the bathymetry in the outer zone of the beach. Finally, beach nourishment is proposed in order to restore the beach and protect the cliffs, and some questions are formulated for guiding future works in the site. [ABSTRACT FROM AUTHOR]

In many aeolian studies, it is commonplace to use Bagnold's (1936) equation to calculate threshold shear velocity (u*t), which includes an empirical constant, A, typically set at about 0.082 for maintaining saltation (the dynamic, or impact, threshold). Here, we present data from a pilot study to assess the variability of A to improve estimations of u*t, which in turn, should improve transport rate predictions. Using field data from three coastal environments, we measured or calculated all parameters within the Lettau and Lettau (1978) model and u*t equation. In Jericoacoara, Brazil (BRA), Inch, Ireland (IRE), and Esposende, Portugal (POR) wind velocities were measured with cup anemometer towers and transport rates were measured using traps for 31 data runs lasting 120 to 1020 seconds each. Mean grain sizes were 0.17 mm (IRE), 0.31 mm (POR), and 0.30 mm (BRA), and mean shear velocities were 0.38 m s-1 (IRE), 0.40 m s-1 (POR), and 0.49 m s-1 (BRA). Empirically determined, adjusted A values ranged from 0.02 to 0.21 with a mean and standard deviation of 0.11 and 0.04. No relationship exists between estimates of A and grain Reynolds number. A statistically significant (p < 0.001), negative relationship was found between A and mass transport rate, leading to substantial overprediction of transport rates near the threshold and under-prediction during fast winds if a constant of 0.082 is used. [ABSTRACT FROM AUTHOR]

The Solís Chico river, located on the southern Uruguayan coast, flows into the Río de la Plata estuary. The seaside resorts La Floresta and Parque del Plata are located on the estuary. In recent years the river mouth has migrated westward, away from the river axis, forming a sand spit that hinders the recreational use of Parque del Plata beach. In turn, at La Floresta there is a beach nourishment project whose main objective is to mitigate the erosion of the beach and the adjoining cliffs. This work aims to identify the causes of the recent migration of the river mouth and to analyze the possibility of using the sand spit as a borrow area for the beach nourishment. The river sediment supply to the coast for the period 1900-2010 was estimated, along with the long-shore and cross-shore sediment transport produced by sea waves. Furthermore, the plan-view stability of the river was studied in order to determine if the long-term evolution of the river is affecting the migration of the mouth. It was found that the migration of the mouth is mainly due to an extraordinarily high river sediment supply in 2002, combined with an increase in the net westward potential long-shore transport rate since the late 90s, and that the meander dynamics of the river are not affecting the evolution of the mouth. Additionally, the most likely area of natural breaching of the sand spit was identified, recommending its use as a borrow area for nearby beach nourishment. [ABSTRACT FROM AUTHOR]

Detailed video images and ADCP measurements were used to describe the processes of suspended sediment transport by the Mataquito River into the Pacific Ocean. It is found that, in the absence of fluvial flood discharges, suspended sediment transport to the sea only takes place during low tide periods and it is characterized by pulses of different frequencies that in turn are related to the spatial velocity distribution at the river inlet. It was observed that at low tide the highest velocities are near the mouth of the river, presenting an heterogeneous spatial distribution. In this high speed zone, we hypothesized the shear stresses are big enough to re-suspend fine sediment that is transported into the ocean by the main river current. A simple conceptual explanation based on these findings is presented, seeking to explain the observed dynamic equilibrium of the Mataquito River inlet after the significant alterations produced by the 2010 M8.8 earthquake and tsunami. [ABSTRACT FROM AUTHOR]

On May 29, 2006, mud and gases began erupting unexpectedly from a hydrocarbon exploration well near Sidoarjo, East Java, Indonesia. The eruption, called the LUSI (Lumpur Sidoarjo [Lumpur means mud in Indonesian]) mud volcano, has continued since then at rates as high as 180,000 m³ per day. The mud inundated an area in excess of 6.5 km², in spite of attempts to contain it via the construction of a series of levees. The mud is erupting and accumulating behind the levee system. It is also being pumped into the Porong River, which then carries the mud to the ocean approximately 20 km to the east. The main objective of this study is to assess the effect of mudflow from the LUSI volcano on the river and estuary environment such as sediment deposition and water quality using the observed river cross sections and bathymetry data after the eruption of the LUSI volcano. From the analysis it was found that a significant sediment deposition occurred at the river bed of Porong River due to increased sediment discharge from the volcano during the dry periods after which the sediment deposits on the river bed were gradually eroded and flushed away to the ocean by floods and high water flows during the wet periods. Environmental impacts due to increased sediment from the Porong River on the estuary and coastal region are discussed. [ABSTRACT FROM AUTHOR]