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Kim, H.-C.; Song, Y.-S.; Kim, Y.H.; Son, S.; Cho, J.-G.; Chang, W.K.; Lee, C.-H.; Nam, J., and Ryu, J., 2018. Implications of esuarine and coastal management in the growth of Porphyra sp. in the Geum River Estuary, South Korea: A modeling study. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 396–400. Coconut Creek (Florida), ISSN 0749-0208. Laver (Porphyra sp.) is one of macroalgae species that has been cultivated for the purpose of food consumption in the coastal areas of Korean Peninsula. In specific, Porphyra tenera Kjellman and Porphyra yezonensis Ueda are two major commercial species for aquaculture in the west coast of Korea. In this study authors employed an ecosystem modeling approach (Hadley et al., 2014) to simulate the nutrient physiology and growth of the laver in aquaculture facilities located in the vicinities of Geum River Estuary. Some of model coefficients and parameterizations were modified from the original version based on laboratory experiments, if necessary. In addition, authors calibrated and validated the Delft3D (https://oss.deltares.nl/web/delft3d) with long-term time series data from the area. The Delft3D is an open source modeling suite that can simulate hydrodynamics (temperature, salinity, flow fields), sediment transport and water quality variables (inorganic nutrients). As one of the end-point goals of the present study is to develop decision supporting tools that can be used by coastal managers, the macroalgae growth model was coupled with the Delft3D in order to predict effects of episodic climatic events and/or upstream water management decisions on the estuarine ecosystem. Temperature, salinity and nitrogen loadings estimated from the Delft3D were used as input to the ecosystem model, and subsequent responses from Porphyra sp. were numerically simulated. Given thirteen scenario-based simulations, it is found that model simulated dissolved inorganic nitrogen concentrations do not change significantly for the same climatic condition. However, the maximum potential annual production of macroalgae is found to be more dependent on ammonium ion concentration. [ABSTRACT FROM AUTHOR]

Chang, Y.S.; Huisman, B.; Boer, W., and Yoo, J., 2018. Hindcast of Long-term Shoreline Change due to Coastal Interventions at Namhangjin, Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 201–205. Coconut Creek (Florida), ISSN 0749-0208. Namhangjin beach is protected by multiple submerged breakwaters (SBWs) which were built to protect the ~4 km long sandy beach. A coastline model (UNIBEST) was used to investigate the long term effect of the SBW structures on the beach. The model computes long-term shoreline changes due to coastal structures as a result of the strong longshore sediment transport gradients at the structures. Bathymetry data of the shoreface and nearshore profiles were obtained from a field survey, while wave conditions from offshore WAM hindcast (Wave Modeling Group) were transformed towards the nearshore with the Delft3D+SWAN modelling system. Local wave sheltering by the SBWs was included in the wave model. A situation with and without the SBWs was modelled. A rapid adjustment of the shoreline was observed in the model as a result of the wave conditions in the first two years. After that, the shoreline shape stabilized without significant changes both for the situation with and without SBWs. A smooth curved coastline shape was obtained in the model without SBWs, while the model with SBWs shows a similar overall shoreline shape with undulations of the shoreline shape behind the breakwaters. A similar undulating shoreline was observed in the Sept-2013 imagery at Namhangjin beach. The local accretion behind the SBWs may induce some erosion in the lee area of the SBWs, causing distortions of the shoreline shape. Most sediment accreted at the first SBW (i.e. the northern most SBW where alongshore transport from the North was trapped), while the coastline change rate gradually decreased towards the South. The effectiveness of the SBWs at the considered shoreline section for maintaining the shoreline is somewhat ambiguous as local areas with accretion or erosion are present with respect to the situation without the breakwaters. The results show that multiple SBWs need to be carefully designed to protect beaches as local distortions of the shoreline shape may be present directly downdrift from the structures. [ABSTRACT FROM AUTHOR]

Small tidal inlets with an entrance width of less than 50 m or a cross-sectional area of less than 100 m2 have not been investigated as often as their larger counterparts. To discern the major processes responsible for entrance infilling in a small inlet system, the hydrosedimentological processes in the annually dredged Currumbin Creek (Australia) inlet system were investigated. Delft3D was applied and validated using local field measurements and regional data. A standalone regional hydrodynamic model and three nested standalone wave models provided detailed data for the offshore boundary of the more detailed creek entrance model, which was a coupled, local flow-wave-sediment transport model. The noncohesive sediment transport module was calibrated based on the volume of dredging and the net annual volume of longshore transport. The results of this hindcast model provided insight into the dominant processes responsible for the inlet's current configuration (i.e. significant refraction of incident waves to a nearly shore normal direction; a noteworthy onshore-offshore transfer of sediments; channel infilling induced by wave-induced currents; very limited sediment transport within the back-barrier lagoon because of an absence of wave-induced currents, as well as weak tide-induced currents; and infilling of the dredged area because of immersed slope stability, rather than hydrodynamic processes). Overall, the adopted modelling approach and the selected model setups proved to be a suitable combination of the available resources and tools to forecast the influence of any alteration to the current maintenance strategy. Accordingly, the identified physical processes and findings can be applied to similar cases with narrow inlet entrance widths and small back barriers with limited circulation. [ABSTRACT FROM AUTHOR]

López-Dóriga, U. and Ferreira, Ó., 2017. Longshore and cross-shore morphological variability of a berm-bar system under low to moderate wave energy. The morphological variability of a berm-bar system is highly dependent on wave conditions with direct consequences for the evolution of the nearby coast; however, an understanding of this variability based on field measurements is still lacking, in particular with respect to the assessment of both longshore and cross-shore components. In this study, the berm-bar morphological changes were assessed by simultaneously measuring longshore and cross-shore variability as well as the forcing mechanisms ( i.e. wave conditions). A sandy beach in southern Portugal (Tavira Barrier Island, Ria Formosa) was surveyed from the dune crest to 20-m depth along six profiles over a period of 16 months. Wave time series between surveys were analysed to obtain relationships between wave conditions, the depth of closure, and berm-bar variations. For the surveyed period, waves approached mainly from the W-SW (78% of the time) and E-SE (18%), and eight moderate storms were recorded. Results show that the active zone of the profiles descends to 6 m below mean sea level (MSL), the maximum depth of closure registered. On the basis of the pattern of vertical variability, the profiles can be divided into three cross-shore sectors: A (emerged beach and berm), B (subtidal terrace), and C (submerged longshore bar). A new index (longshore vs. cross-shore [LvC]) is proposed, relating the dominance of longshore or cross-shore processes to volumetric changes resulting from sediment transport. In the study area, cross-shore sediment transfer (LvC ∼ 0) dominated when the largest and longest storms occurred and is associated with storm erosion and poststorm recovery. Longshore dominance (LvC ∼ −1 and 1 for erosion and accretion, respectively) occurred during periods with smaller and shorter storms. The proposed index allows the relative roles of cross-shore vs. longshore processes in coastal areas with berm-bar interaction to be distinguished. [ABSTRACT FROM AUTHOR]

Marcomini, S.; López, R.; Picca, P.; Madanes, N., and Bertolín, L., 2017. Natural coastal dune-field landforms, plant communities, and human intervention along Buenos Aires northern aeolian barrier. The dune field that stretches NE of Buenos Aires coast has been altered by urbanization since the early 20th century, with a maximum urban growth reached in 1970 that generated important changes in natural dune landforms and vegetation cover. The introduction of some exotic shrub and tree species has increased dune-field stabilization and changed wind transport rates on it and toward the beach. This lack of aeolian sediment supply to the beach caused subsaturation in marine littoral drift currents, increasing beach erosion along several resorts located along the northern Buenos Aires coast. Additionally, some native herbaceous species, at some time dominant in the past in dune communities, have been replaced by these foreign woody plants, altering consequently the structure and composition of the original plant communities and, indirectly, dune growth, activity, and mobility. The purpose of this paper is to study the original geomorphology and some basic attributes of the natural plant communities that characterize the coastal dune field to establish the relationship between the original aeolian dynamics and man-induced changes in the evolution of the coastal system. This study documents dune morphology and salient aspects of the associated vegetation (floristic composition, abundance of each species) over an original dune field and discusses the impacts of afforestations accompanying dune-field real-state developments. In the future, coastal management should regulate the expansion of forested areas in the dune barriers and preserve natural dune fields as potential reserves of sand for beach equilibrium. [ABSTRACT FROM AUTHOR]

Fellowes, T.E.; Gacutan, J.; Harris, D.L.; Vila-Concejo, A.; Webster, J.M., and Byrne, M., 2017. Patterns of sediment transport using foraminifera tracers across sand aprons on the Great Barrier Reef. Sediment dynamics exert large control over coral reef geomorphological evolution and are vital to understanding past and present geomorphic responses. Large benthic foraminifera (LBF) live in the algal reef flats, and their tests (shells) are transported post-mortem by waves and currents onto back-reef environments, including sand aprons. This study investigated the patterns of transport linking surficial and downcore sediments in samples from three sand aprons with different wave exposures at One Tree Reef on the southern Great Barrier Reef (Australia). Six LBF genera represented up to 32% of the sediments analysed. Lagoonward transport increased LBF test abrasion and sediment bulk density. Sediment grain size and LBF abundance in sediments also decreased with lagoonward transport. Sediment transport patterns indicated by LBF species used as tracer were consistent with the prominent E-SE wave environment. A novel taphofacies approach was used to describe stratigraphic layers in downcore sediments based on LBF test abrasion and abundance. Varied sediment deposition rates did not affect the LBF test abrasion signature downcore. It appears that Baculogypsina sphaerulata has been the dominant species for at least 3 ka. Tests that were deposited slowly exhibited less or the same levels of abrasion than those that were rapidly deposited. It appears that test abrasion is primarily determined by the distance travelled rather than the influence of increased age or chemical dissolution. [ABSTRACT FROM AUTHOR]

Chávez Cárdenas, X. and Kobayashi, N., 2017. Movement of wooden blocks on ground and pilings in swash zone. In: Martinez, M.L.; Taramelli, A., and Silva, R. (eds.), Coastal Resilience: Exploring the Many Challenges from Different Viewpoints. Journal of Coastal Research, Special Issue No. 77, pp. 7-18. Coconut Creek (Florida), ISSN 0749-0208. Time-varying interactions among storm surge, waves, sand beaches, and wooden houses determine the degree of damage to the houses on low-laying beaches but the complicated damage process is not well understood. An exploratory laboratory experiment consisting of eight tests was conducted in a wave flume with a sand beach to examine the movement of ten wooden blocks (idealized houses) on the foreshore and berm as well as on short and long pilings. The still water level was varied to create accretional and erosional profile changes on the foreshore and berm. The cross-shore wave transformation on the beach and the wave overtopping and overwash of the berm were measured in 71 runs of 400-s each. The initial block elevation above the sand surface is shown to have little effect on the hydrodynamics, sediment transport, and profile evolution in this experiment with widely-spaced blocks. The block floating and sliding on the sand surface and block falling from the pilings depended on the swash hydrodynamics and block clearance above the foreshore and berm whose profile varied during each test. A probabilistic model is developed to estimate the wetting, sliding, and floating probabilities for the block in the swash zone using the water depth measured in the vicinity of the block. The estimated probabilities are used to explain the observed block floating and falling. [ABSTRACT FROM AUTHOR]

Lee, J.; Park, S.-K., and Hong, S., 2017. Numerical simulations of local scour at Samsan Bridge piers in Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 154-158. Coconut Creek (Florida), ISSN 0749-0208. The Samsan Bridge connects Ganghwa Island and Incheon in the mid-western region of South Korea. The country is making an effort to improve access to the island from its major cities, and the construction of the bridge is part of that process. External factors such as wind waves, tide currents, currents, and scour depths around piers should be considered in the construction of a bridge. In order to obtain scour depth values around bridge piers, this study conducted numerical simulations on morphological changes using the SADEM (SAnd Deposit and Erosion Model). The morphological changes were calculated by solving the conservation of sediment transport equation. A field measurement was performed at the Seokmo channel in the Han River estuary (South Korea) to verify the numerical results. A 153×210 grid system with a coarse grid size of 22.8 × 30 km was used in the SADEM. The maximum stream velocities of 10, 50, and 100-year flood return periods during the ebb tide contributes to sediment mobilization in the Seokmo channel. The maximum scour depth was calculated to be 9 m around the central bridge's pier during the flood ebb for the 100-year return period. This was due to the upstream discharge during river flooding. The results of the numerical simulations are expected to be objective indicators of optimal design, construction, and future maintenance of the Samsan Bridge. [ABSTRACT FROM AUTHOR]

Shin, S.; Nam, J.; Son, S.; Kim, I.H., and Jung, T.-H., 2017. Field observation and numerical modelling of rip currents within a pocket beach. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 229-233. Coconut Creek (Florida), ISSN 0749-0208. Understanding the occurrence mechanism of rip currents are very important in terms of the sediment transport and the water safety issues. In order to investigate the rip current occurrence mechanism, field observations were carried out at Chunjin beach and a numerical model was employed to simulate rip currents by using the field observation data. The collected data set includes the beach topography, bottom bathymetries, shoreline, sand sample, and incident waves for each season. The field observation data showed the spatiotemporal variations of shoreline and sand bars. The results also showed that the rip currents were generated near the crescentic sand bar. For better understanding the mechanism of rip currents, numerical simulation using phase- resolving, three-dimensional 3D Non-Hydrostatic WAVE Model (NHWAVE) was also carried out. The model considered incoming wave conditions collected from the field observation to look at the nearshore current generation patterns. Through this numerical model, this study could have investigated vertical profiles of nearshore wave-induced current while the field observation data represent depth uniform currents. The numerical simulation showed a good agreement with the field observation and provided useful information for nearshore circulation. [ABSTRACT FROM AUTHOR]

Jeon, H.S.; Obana, M.; Kim, K.H., and Tsujimoto, T., 2017. Flow and sediment transport with non-submerged riparian vegetation in 1D scheme. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 329-333. Coconut Creek (Florida), ISSN 0749-0208. Recently depth averaged analysis has become popular and powerful even in a stream with vegetation by taking account of form drag due to vegetation. A number of studies about the drag force related with various vegetation configuration were also carried out and focus on determining the drag coefficients and empirical formulas. However, there must be some restriction for application in depth averaged model for flow with vegetation. When it is applied to a stream with vegetation, form drag due to vegetation is taken into account, but the shear stress is not properly described because the frictional resistance law due to bed roughness is not modified in vegetated area. Therefore, friction factor in depth-averaged scheme must be modified by the flow with vegetation. In this paper, the concept of 'bed roughness boundary layer' is proposed and analytically formulated against the vegetation density. Sensitivity analysis were also conducted under several parameters and vegetation densities. The calculated results bring the reasonable evaluation of shear stress and proposed concept will affect other many kinds aspect in fluvial process, which will be clarified successively. Resultantly we are able to apply the depth-averaged analysis reasonably to flow and fluvial process in a stream with various density of vegetation. [ABSTRACT FROM AUTHOR]

Kim, H.-J.; Suh, S.-W.; Seok, J.-S., and Park, W.-K., 2017. Sedimentation for a flood-dominant estuarine harbor induced by anthropogenic activities. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 339-343. Coconut Creek (Florida), ISSN 0749-0208. Sedimentation around the Kunjang harbor area in Korea has intensified at a rate of ~2.0 m/yr because of the construction of an estuarine dam in 1988, which resulted in the tidal energy being blocked and the development of a flood-dominant environment. The construction of several harbor facilities cumulatively altered the tidal hydrodynamics and yielded sedimentation. Moreover, the annual maintenance dredging for the main channel accelerated alteration. In order to understand the sedimentation characteristics, archived intensive depth measurements were used to assess the variations in the bottom shear stress. Our results showed that the bottom shear stress and tidal prism have lessened. The resulting sedimentation should be managed through dredging or minimization plans based on an appropriate engineering solution. In this paper, we suggest an optimized weighting factor to represent diverse physical morphological variations that affect the shear stress. It can be used to compensate for unsatisfactory results generated by a morphological model. Our findings can help in devising an efficient engineering approach to mitigate sedimentation for a flood-dominant estuarine harbor. [ABSTRACT FROM AUTHOR]

Son, S.; Kim, J.; Yoon, H.-D.; Jung, T.-H.; Do, K., and Shin, S., 2017. An observational and numerical study of storm-induced morphologic changes at Sanpo Beach, Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 334-338. Coconut Creek (Florida), ISSN 0749-0208. This study was conducted to investigate morphological changes at Sanpo Beach due to the storm through field observation and numerical simulation. Sanpo Beach located on the southeast coast of Korea had been significantly affected by typhoon Goni while some changes in beach profile was expected due to the strong storm-induced currents. Series of field observations on the beach topography, bottom bathymetries, shorelines, sand samples, and incident waves were carried out in order to investigate the morphological changes at Sanpo Beach during the typhoon season. In particular, Real Time Kinematic-Global Positioning System (RTK-GPS) and single-beam echo-sounder were deployed to collect beach topography and bottom bathymetry data, respectively. Observational results represented spatial and temporal changes of shoreline and sand bars during a storm event. For more close look at the process of morphologic changes derived by the sediment transport mechanism, field-scale numerical simulations were performed in parallel using Xbeach. Xbeach is one of the widely-used, open-source models which calculate sediment transports and morphologic changes by hydrodynamic processes of short (and/or long) waves, wave-induced setup and unsteady currents. Bathymetric evolutions, as well as shoreline changes predicted by the numerical results, revealed good agreements with observational data. [ABSTRACT FROM AUTHOR]

Wang, P. and Beck, T.M., 2017. Determining dredge-induced turbidity and sediment plume settling within an intracoastal waterway system. The intracoastal waterway (IWW) is a continuous navigation channel that often extends across seagrass beds and other sensitive habitats throughout the Gulf and Atlantic Coast estuaries of the United States. Turbidity increase associated with an IWW dredging operation in west-central Florida and subsequent dredge plume subsidence were measured with optical backscatter sensors and acoustic Doppler velocimeters, which also measured in situ wave and current conditions. The field experiments were conducted over a dense seagrass bed. Sediment in the study area is dominantly composed of fine, well-sorted quartz sand, typical of Florida estuaries. The dredge plume temporally increased the turbidity to more than 400 mg/L around a midwater depth. The settling of the dredge plume and sediment resuspension were calculated with commonly used empirical formulas for noncohesive sediments and compared with field observations. The relatively energetic conditions generated by frequent boat wake did not result in significant resuspension and remixing of the suspended sediments and had minor influence on the settling time of the dredge plume. Findings from this study may provide information on understanding potential impacts of dredging on seagrass beds. [ABSTRACT FROM AUTHOR]

Wegner, C.E. and Ellis, J.T., 2017. The influence of sea-level rise on wave-energy dissipation and wave-driven currents at Buck Island Reef National Monument. Modern Caribbean reefs have undergone significant degradation in the past century because of various anthropogenic stressors, which include climate-change-related impacts, hurricanes, and, potentially, sea-level rise. Degraded reefs will be unable to maintain sufficient vertical accretion with substantial increases in sea level, which will alter the hydrodynamics of these systems. A reduction in wave dissipation by reefs has the potential to shift the shorelines behind the reefs, potentially resulting in economic and habitat losses for tropical shorelines. This study focused on a barrier reef with low, live coral cover (<10%) and accretion rates comparable to current rates of sea-level rise in the region (∼1.7 mm/y). Tides served as a proxy for sea-level rise, with the spring high tide representing a future low tide. These findings indicate that at low tide, infragravity wave frequencies (0.004-0.04 Hz) dominate in the lagoon and are a function of wave breaking on the reef. At high tide, the infragravity waves are less prominent. Current velocities were higher at high tide, averaging 0.14 m s−1 vs. 0.11 m s−1 at low tide. The spectral current characteristics correlate with the infragravity wave frequencies and suggest that these waves are a driving force in lagoon circulation. Wave-energy transmission increased at high tide by 20-30% throughout the sampling period. These results suggest that with sea-level rise, infragravity band waves will be reduced and affect the stresses on the sea bed and sediment-transport processes, also allowing larger and more energetic waves to reach the shoreline. [ABSTRACT FROM AUTHOR]

Kawanisi, K.; Zhu, X.-H.; Fan, X., and Nistor, I., 2017. Monitoring tidal bores using acoustic tomography system. Continuous measurements of flow velocities and suspended sediments were carried out in the Qiantang River (China) with extreme tidal bore conditions. Fluvial and coastal acoustic tomography systems (FATS/CATS) were used in the field studies simultaneously with acoustic Doppler current profilers (ADCPs) and optical backscatter (OBS) equipment. A couple of broadband transducers were installed diagonally across the river around 90 km upstream of the mouth. The length of the sound transmission line was 3050 m. Cross-sectional averaged velocities ( V) collected by FATS/CATS enabled the authors to estimate important characteristics of the tidal bores (bore height and celerity). The changes in V recorded during the upstream movement of the bore ranged from 1.35 to 1.76 ms−1. The height and celerity of the bore varied from 1.0 to 1.32 m and 7.59 to 8.29 ms−1, respectively. Since a point/vertical measurement cannot represent a river's cross section, the ADCP data for velocity and water level (pressure) near the riverbank underestimated the bore height by 22% and 16%, respectively. The maximum suspended sediment concentration (SSC) was observed to have occurred approximately 1 h after the bore's arrival; the time lag between the maximum SSC and the bore front is considerably larger than the time lags in previous works. In the case of larger bores, the section mean SSCs, which were deduced from the sound attenuation of FATS/CATS due to suspended sediment, appeared to be appropriate. The time history of the velocity, measured by ADCPs, during the passage of the bore deviated from the normal velocity profile, i.e. the velocity magnitude decreased with an increasing height above the bed for the relaxation time of a few minutes following the arrival of the bore. [ABSTRACT FROM AUTHOR]

Restrepo, J.C.; Escobar, J.; Otero, L.; Franco, D.; Pierini, J., and Correa, I., 2017. Factors influencing the distribution and characteristics of surface sediment in the Bay of Cartagena, Colombia. This study evaluated patterns of coastal sediment movement and deposition under different seasonal conditions (warm and cold phases of the El Niño-Southern Oscillation [ENSO] and normal conditions) in Cartagena Bay, Colombia. A calibrated numerical model (MOHID modeling system) was applied to assess the spatial distribution of sediments transported by the Canal del Dique to the bay and studied the spatial distribution and major textural characteristics of 234 surface sediment samples. Currents in the Bay of Cartagena are controlled primarily by the strength and direction of the wind. Model results show major sediment deposition in the southern sector of the bay during the dry season. More homogenous spatial distribution of sediments throughout the Bay of Cartagena occurs with an increase in river inputs from the Canal del Dique. These patterns were enhanced or weakened, respectively, by cold and warm phases of the ENSO. Predominant sediments were medium size (ϕ = 5.35 ± 1.2), poorly sorted (σ = 1.63 ± 0.8), with notable asymmetry (Sk = −0.052 ± 0.2) and kurtosis ( k = 0.84 ± 0.4). Sediments with lower sand content (<5%) are located along a latitudinal axis from the Canal del Dique delta to the western end of the island of Tierrabomba. CaCO3 content of the sediments is <10%. Water and sediment flow, controlled by the Canal del Dique, has favored the transport and deposition of poorly sorted, symmetric, and mesokurtic mud in most of the Bay of Cartagena. As a result, autogenous calcareous sediments have been covered by fine terrigenous sediments that were delivered via the Canal del Dique. Thus, the channel plays a more prominent role in sediment transport and deposition in the Bay of Cartagena than thought previously. [ABSTRACT FROM AUTHOR]

Johnstone, E.; Raymond, J.; Olsen, M.J., and Driscoll, N., 2016. Morphological expressions of coastal cliff erosion processes in San Diego County. In: Brock, J.C.; Gesch, D.B.; Parrish, C.E.; Rogers, J.N., and Wright, C.W. (eds.), Advances in Topobathymetric Mapping, Models, and Applications. Journal of Coastal Research, Special Issue, No. 76, pp. 174-184. Coconut Creek (Florida), ISSN 0749-0208. High-resolution, Terrestrial Laser Scanning (TLS) data have been acquired seasonally since 2006 to define the style and magnitude of cliff erosion along the southern 20 km of coastline within the Oceanside Littoral Cell (OLC). In particular, twelve sites with cliff collapses were mapped repeatedly to examine how these collapses propagate along the cliffs and to identify feedback mechanisms between the liberated material and subsequent cliff failures. Grain size analyses of the failed material (retention cutoff) were performed to estimate the contribution to the beach sand inventory. Despite a relatively short time series (only six years) on a geologic scale, the high spatial and temporal resolution of the study has provided important insights into the fine details of processes controlling cliff erosion in the OLC. In addition, the seasonal TLS established a quantitative baseline from which future change may be assessed. Both lithological and environmental conditions are known to play a major role in governing the rate and style of cliff erosion; however, other factors such as beach width, elevation, and precipitation also exert control on rates and styles of cliff failures. The findings of this study reveal that cliff erosion is subaerially dominated where the beaches are wider and elevation is higher. Alternatively, erosion is marine dominated where the beaches are narrow and have lower average elevation. A direct relationship exists between beach elevation and undercutting and erosion along the failure edges and thus might provide a mechanism to create the observed linear retreat of the cliffs in the OLC rather than the formation of promontories and embayments. Other morphological expressions on the cliff face, such as honeycomb patterns and sawtooth-style frontage, indicate mechanisms that control predominant styles of erosion in particular locations. This time series documents seasonal and short-term erosional patterns and rates as well as establishes a baseline to understand cliff erosion in response to rapid sea level rise (>3 mm/yr). [ABSTRACT FROM AUTHOR]

Olsen, M.J.; Johnstone, E.; Driscoll, N.; Kuester, F., and Ashford, S.A., 2016. Fate and transport of seacliff failure sediment in southern California. In: Brock, J.C.; Gesch, D.B.; Parrish, C.E.; Rogers, J.N., and Wright, C.W. (eds.), Advances in Topobathymetric Mapping, Models, and Applications. Journal of Coastal Research, Special Issue, No. 76, pp. 185-199. Coconut Creek (Florida), ISSN 0749-0208. Continual erosion and collapse of unstable seacliffs along the economically important coastline of San Diego County, California, threatens existing development and public safety. Frequent time-series mapping of the seacliffs and beaches provides valuable insight into the processes responsible for cliff erosion and into the reworking and transport of the failed material. High-resolution terrestrial laser scan (TLS) data provide quantitative data for analyzing seacliff morphology, capturing patterns over time and across a wide range of spatial scales. Through an ongoing 'rapid response' program operational since spring 2007, eleven substantial seacliff failure sites were mapped pre-collapse, immediately post-collapse, and repeatedly after the collapse to constrain processes causing cliff failure and estimate the rate at which failed material is reworked. Comparison of the TLS data with water levels and climate data highlights the contributing mechanisms to the seacliff failures and the rapid reworking of the failed material. Failure sites were categorized based on the frequency of wave contact ( i.e., total water level) compared with the beach elevation to assess differences in the rates of sediment reworking. For example, unconsolidated failed material on the beach was reworked quickly by waves at sites where waves reached the failure on a nearly daily basis. Conversely, other failure masses with less wave contact were only reworked during storm events producing larger waves. At sites where the failure material consisted of large boulders, there are feedback mechanisms at play where the failed material protects the cliff toe by stabilizing talus deposits, akin to riprap engineering techniques. Failures due to wave undercutting and notching were observed to migrate laterally at these sites. This lateral progression of failures might explain the long-term linear retreat of the seacliffs in the region, which minimizes the development of embayments and promontories. [ABSTRACT FROM AUTHOR]

Kong, J.; Pan, M.; Shen, C.; Hua, G., and Zhao, H., 2016. Analysis of the morphological changes and related sediment transport mechanisms of the Baisha Shoal in the Qiongzhou Strait, China. The morphological changes and evolutionary mechanism of the Baisha Shoal in the Qiongzhou Strait were investigated using various methods, including bathymetric chart comparisons, geomodeling, hydrodynamic modeling, and hydrologic statistical analysis. Water depths were extracted from digitized charts to explore the evolution of the Baisha Shoal and to quantitatively estimate the changes in the shoal area within the 5-m isobath. The grain-size trend analysis (GSTA) model was introduced to explain the features of bed sediment distribution and to analyze the sources of the sediment. Tidal flow models and wave models were adopted to simulate the tidal flows and wave fields around the Baisha Shoal and to reveal the sediment transport dynamics. Further comparisons based on a Mann-Kendall trend analysis and remote-sensing image data from different years were used to discuss the reason for the recent evolution of the Baisha Shoal. The results show that the formation of the Baisha Shoal was caused by the combined effects of reciprocating flow in the eastern and western directions and waves from the NE direction. However, in recent years, the Baisha Shoal has demonstrated an unsteady geomorphological state and is transitioning from a deposition-dominated state to an erosion-dominated state. Erosion has become most significant since 2004, as reflected in the shoal area within the 5-m isobath, which is decreasing by 0.732 km2/y. The analysis demonstrated that a reduction in sediment load and increased sand mining are the two most significant factors that are progressively altering the shoal morphology. If these issues cannot be resolved, the strong dynamic surroundings will aggravate the erosion of the Baisha Shoal. This study on the Baisha Shoal highlights the necessity of combining different approaches to better understand coastal evolutionary features, dynamic mechanisms, and evolutionary causes, as well as to guide future coastal protection engineering design. [ABSTRACT FROM AUTHOR]

van Gaalen, J.F.; Tebbens, S.F., and Barton, C.C., 2016. Longshore sediment transport directions and rates from northern Maine to Tampa Bay, Florida: Literature compilation and interpretation. This paper examines site-specific and regional longshore sediment transport directions and rates along the U.S. seaward coast from the northern Maine border to the mouth of Tampa Bay, Florida. From previous studies, it is known that along the coast, there are nodal zones, i.e. locations of divergence or convergence in longshore current, as well as variations in current direction and sediment transport rate. Available published field-based studies of sediment transport directions and rates were compiled to create a map of the direction and rate of longshore transport. A detailed compilation of local and regional published studies is provided in tables and in a sequence of eight regional maps. Compiled studies of longshore transport reveal a dominant southward direction. On the regional scale, 12 nodal zones are identified. At the local scale, the number of nodal zones increases by approximately an order of magnitude. This work builds upon the Master's thesis of van Gaalen (2004). [ABSTRACT FROM AUTHOR]

Tan, C.; Huang, B.; Liu, F.; Yang, Q.; Jiang, C., and Zhang, S., 2016. Transformation of the three largest Chinese river deltas in response to the reduction of sediment discharges. The Yellow, Yangtze, and Pearl rivers deliver more than 1.2 × 1012 m3/a of freshwater and 13.6 × 108 t/a of sediment into the western Pacific Ocean, playing important roles in the morphological evolution of the ocean in this region. From the 1950s to the 2000s, the total sediment loads of the three rivers decreased by 81.2%; this change has been primarily caused by human activities, such as dam construction and water-soil conservation projects. The sediment loads in the Yellow, Yangtze, and Pearl rivers decreased by 89.9%, 62.1% and 57.1%, respectively, from the 1950s to the 2000s. In response to the sediment supply decrease, the sediment regimes of the river channels in the lower reaches of the three rivers generally transitioned from deposition to erosion since the 1990s. The erosion of the channel has modulated the characteristics of the suspended sediment delivered to the estuary; for example, the erosion of the lower river channel increased the sediment flux and caused relatively coarser suspended sediments to be delivered to the estuary. As a consequence of the changes in the river basins, the evolutions of the three river deltas have transformed in the 2000s. The subaqueous deltas of the Yellow and Yangtze rivers changed from deposition to erosion. However, the Pearl River delta generally prograded seaward, and a portion of its subaqueous delta ( e.g., the Modaomen River mouth) underwent erosion. In the coming decades, the sediment discharges into the seas from these three rivers are likely to decrease further because of intensifying human activities. Therefore, enhanced erosion in the three river deltas will continue when the river deltas remain unprotected. Our study demonstrates that human activities in the three river basins can influence the morphological changes of the estuaries, indicating that a river basin and its coastal zone are an integrated system. [ABSTRACT FROM AUTHOR]

Gibeault, C.; Neumeier, U., and Bernatchez, P., 2016. Spatial and temporal sediment dynamics in a subarctic salt marsh (Gulf of St. Lawrence, Canada). Sediment transport in the salt marsh and the lagoon of Penouille is driven by tidal currents, waves, wind, and ice rafting, which interact with topography and vegetation to control the spatial distribution of surface sediments. Multiple linear regressions of 203 samples of marsh surface sediments show that grain size gets finer and organic matter content increases with distance from the lagoon inlet, the sandy peninsula, the closest creek, and the lagoon. The vegetation parameters and surface microtopography have only a minor influence. Locally, grain size can get finer with elevation, while organic matter content increases. However, across the entire marsh, grain size exhibits the opposite trend with elevation, a consequence of aeolian transport and ice rafting. The 94 samples covering the lagoon show a trend of finer grain size with distance from the lagoon inlet and with sea grass cover. Penouille marsh has been relatively stable from 1975 to 2008: analysis of five georeferenced aerial photographs shows that only 3% of the marsh area was lost due to outer marsh edge retreat. Ten sediment cores collected in the marsh show a thickness of 0.14-0.72 m of marsh sediments overlying a sandy substrate. Radiocarbon dates suggest that marsh establishment occurred in the north side of the lagoon around 1000-1200 cal BP. Accretion rates based on radiocarbon dates are 0.4-1 mm/y for several centuries, whereas 137Cs dating indicates rates of 1-3 mm/y since 1963, and accretion plates indicate 2.9 ± 0.9 mm/y between 2010 and 2012. Accretion rates since 1963 are similar to the relative sea-level rise (RSLR) of 1.5 mm/y at Penouille for the 1969-2014 period. However, the accelerated RSLR of 3.7 mm/y observed over the last 20 years and additional RSLR due to climate change may progressively drown the marsh if accretion rate does not substantially increase. [ABSTRACT FROM AUTHOR]

Vieira da Silva, G.; Muler, M.; Prado, M.F.V.; Short, A.D.; Klein, A.H.F., and Toldo, E.E., Jr., 2016. Shoreline change analysis and insight into the sediment transport path along Santa Catarina Island north shore, Brazil. This paper presents a shoreline change analysis applied to identify the sediment transport path involving nine adjoining beaches, including dunes and spits, located along the microtidal eastern and northern shores of Santa Catarina Island (Brazil) and extending 50 km from Barra-Moçambique to Daniela. A data set was comprised of aerial images from 1957, 1978, 1998, 2002, 2007, and 2010, and the 2012 shoreline position measured with real-time kinematic GPS, topobathymetric data set, and a 60-year water-level time series. The images were rectified and the shoreline position for each year was extracted. The average errors (ranging from 1 to 9.8 m) of the rectification process as well as the horizontal tide-related errors (varying from 8.3 ± 2.6 m to 14.9 ± 0.6 m) were calculated within a confidence level of 95%. Two complementary approaches were used: (1) general trends analysis using linear regression rate method and (2) shoreline behaviour statistically analysed by Euclidean distance and year-to-year analysis. The results indicate an anticlockwise longshore transport between a series of beaches with variable orientation and separated by headlands, including a dune overpassing from Santinho delivering ∼10,000 m3 y−1 to Ingleses, and headland bypassing leading to the development of three spits along the protected part of the study area that have possibly been nourished by subaqueous sand transport from the updrift beaches. During its development the Ponta das Canas spit grew ∼7000 m3 y−1, controlling the sediment availability downdrift. As the spit grows it traps sediment and the downdrift area retreats; on the other hand, when the spit merges to the coast the sand spreads and the downdrift beaches prograde. [ABSTRACT FROM AUTHOR]

Postacchini, M.; Russo, A.; Carniel, S., and Brocchini, M., 2016. Assessing the hydro-morphodynamic response of a beach protected by detached, impermeable, submerged breakwaters: A numerical approach. Coastal areas host a large fraction of the world's population and are exposed to natural extreme events, which are a serious threat to human life, as well as to economies. For this reason, sea storms are increasingly the object of studies, and the design of traditional coastal defenses is being carried out in conjunction with modeling analyses. Relying on numerical simulations performed by means of an innovative shallow-water hydro-morphodynamic model, the present work explores the overall response of a protected beach to sea storms. Numerical tests evaluate the effects of sea states extracted from realistic sea storms having different spectral characteristics, as well as the influence on beach morphology of positioning shore-parallel, impermeable, submerged breakwaters. Simulation results revealed that, while erosion/accretion patterns depend weakly on the different sea state conditions, the morphodynamics induced around the barriers is strongly influenced by the breakwaters' positioning. More specifically, at least for the forcing here analyzed, bed variations were shown to increase when the structures are progressively located offshore; on the other hand, the swash zone morphology seems to be only weakly influenced by the positioning of the breakwaters. We also observed that for an increasing extension of the volume over which dissipative breaking mechanisms occur, a decreasing inshore erosion is accompanied by an equally fast decrease of offshore erosion. Analysis of the vorticity fields shows that breakwaters placed far from the shoreline induce an evolution of the vortices generated by breaking waves rather different from the one due to breakwaters placed closer to the shoreline (which can induce seaward flows through the gap, like rip currents). [ABSTRACT FROM AUTHOR]

Restrepo, J.C.; Schrottke, K.; Traini, C.; Ortiz, J.C.; Orejarena, A.; Otero, L.; Higgins, A., and Marriaga, L., 2016. Sediment transport and geomorphological change in a high-discharge tropical delta (Magdalena River, Colombia): Insights from a period of intense change and human intervention (1990-2010). There is strong indication that environmental changes and human interventions have affected freshwater discharge and sediment flux in the Magdalena River (northwestern South America) within the period from 1990 to 2010. Thus, stream flow, suspended sediment load (SSL), and riverbed dynamics were analysed in this study for estimating changes in the suspended sediment transport regime as well as of erosional/depositional patterns in different zones of the delta. It can be shown that stream flow increased at a higher rate than suspended sediment transport, promoting changes in the sediment transport regime. Erosion appeared at the mouth/frontal bar and the outlet zones and modified the sedimentary balance within the prodelta in the early 2000s. There is indication that cycles of erosion and accretion were controlled by the magnitude of fluvial discharge and riverbed scouring in the river outlet, whereas effluent diffusion and sediment dispersion were dominant in the delta front. High freshwater discharge, as buoyancy inputs, promoted the transfer of sediments from the river channel to the outer prodelta through the upper layers of the water column. Total sediment accumulation in the delta corresponded to <5% of the annual mean SSL of the Magdalena River. Overall, delta morphology remained relatively stable, experiencing a slow progradational state with highest sedimentation rates (≤1430 mm y−1) in the deepest zones. [ABSTRACT FROM AUTHOR]

Cattani, P.E. and Lamour, M.R., 2016. Considerations regarding sedimentation rates along the E-W axis of the Paranaguá Estuarine Complex, Brazil: A bathymetric approach. The sediment dynamics in coastal regions are a result of the coexistence of fluvial, estuarine, deltaic, and shelf depositional environments, as well as the relation among the processes of sediment transport. The Paranaguá Estuarine Complex (PEC) presents different characteristics along its E-W axis, containing areas of port activity. The aim of this study was to identify critical areas of estuarine sedimentary infill and determine their rates and relationships regarding the estuarine environment features. This study employed 38 bathymetric surveys conducted between 1999 and 2008 arranged sequentially from the head of the estuary to the inner continental shelf. Initially, these surveys were grouped chronologically and according to their areas of overlap. Later, they were divided according to grain size and short-term hydrodynamic behavior in four sectors. The sedimentation rates in a portion of the estuary head were 0.60 cm·mo−1·km−2, whereas in the turbidity maximum zone (TMZ), they were approximately 0.06 cm·mo−1·km−2, and in the estuary mouth, they were 0.08 cm·mo−1·km−2. On the inner continental shelf (ICS), a critical area of silting on the terminal lobe of the ebb tidal delta was quantified as 0.56 cm·mo−1·km−2. The differences among silting rates along the PEC are related to the sediment supply for each sector of deposition, as well as the acting hydrodynamic forces. The higher rates found in the inner portion of the estuary may be the result of the advance of river deltas at the head of the estuary, associated with shallow depths and low energy in tidal currents. In the TMZ, silting occurs heterogeneously, with erosion areas associated with rock formations. On the ICS, the area of critical concern in sediment dynamics is the ebb tidal delta, located at the mouth of the PEC, where shallow areas amplify the power transport of the wave energy from the S-SE quadrant , and this energy decreases when entering the channel, allowing deposition. [ABSTRACT FROM AUTHOR]

Sommerfield, C.K., 2016. Qualities and limitations of fluvial suspended sediment data published by the United States Geological Survey. Fluvial suspended sediment concentration (SSC) data published by the United States Geological Survey (USGS) are frequently used to address questions of sediment delivery to estuaries and coasts. Despite the availability of USGS reports detailing methods of sample collection and data processing, many end users remain misinformed about the characteristics and limitations of these data. Two types of USGS-SSC data are available for stream gauging stations: (1) discrete samples and (2) daily record. Discrete samples are laboratory measurements of SSC from water collected at a stream gauging station. In contrast, daily-record data are interpolations of SSC from a smaller number of discrete samples available for a station. A potential source of confusion arises because both types of USGS-SSC data are given the identical description (suspended sediment concentration, mg/L) and parameter code (80154) in the national database. Although the daily-record series for a station is derived from actual samples, discrete and daily SSC values for the same date of record are not always strongly correlated because of factors related to sampling and data processing. As shown in this paper, discrete-sample SSC data series for some stations are inhomogeneous and biased because of changes in USGS sampling practices over the decades, thereby limiting the possible end uses of the data. Ultimately it is up to users to determine which type of SSC data are best suited for a particular application and whether the statistical properties of a data set are conducive to applications such as trend analysis. [ABSTRACT FROM AUTHOR]

McLaren, P., 2016. The environmental implications of sediment transport in the waters of Prince Rupert, British Columbia, Canada: A comparison between kinematic and dynamic approaches. A Sediment Trend Analysis (STA®) was performed on 2474 grain-size distributions taken from the Port of Prince Rupert, British Columbia, Canada. The analysis was commissioned by the Lax Kw'alaams First Nations Band because of environmental concerns associated with future large-scale development plans, including a proposed liquefied natural gas (LNG) terminal associated with Flora Bank. Located at the mouth of the Skeena River, Flora Bank has long been considered an important nursery area for juvenile salmon. STA is an empirical technique to determine patterns of net sediment transport, which may provide a qualitative assessment of the possible environmental changes that could be expected following port construction. The patterns of transport revealed that sediments throughout the study area are derived from underlying till which is exposed in areas of strong currents. Flora Bank, a roughly 4 km2 area of intertidal sand, contained the coarsest and most well sorted sand, which was not found elsewhere throughout the study area. Although derived from till, the sand did not form transport pathways from the other sediment types; in addition, pathways could not be determined on the bank itself. It is concluded that the surficial sediments of Flora Bank are a lag derived from underlying glacial deposits caused as coastal processes became active during a lowering sea level that reached its present position about 8000 years ago. They are, therefore, relict sediments held in place by the processes surrounding the bank. This suggests that the design plan for the proposed LNG terminal could disrupt the processes in such a way that sand could be lost from the bank. This finding is contrary to that derived from numerical modeling, which concludes that no environmental harm will be done. Efforts are presently underway for future collaboration in an attempt to resolve the discrepancy and to more accurately understand the risks to Flora Bank. [ABSTRACT FROM AUTHOR]

Hesp, Patrick A. and Smyth, T.A.G., 2016. Surfzone-Beach-Dune interactions: Review; and flow and sediment transport across the intertidal beach and backshore. 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.8-12. Coconut Creek (Florida), ISSN 0749-0208. The original wave-beach-dune model (Hesp, 1982) stated that in the medium to long term, modal dissipative beaches display maximum onshore wave driven sediment transport, maximum aeolian transport off beaches, the largest foredune heights and volumes, and the largest Holocene dunefields. Modal reflective beaches display the opposite, while modal intermediate beaches display a trend in these from relatively high to relatively low sediment transport, foredune volumes, and Holocene barrier volumes with a trend from dissipative to reflective. New Computational Fluid Dynamic (CFD) modelling of flow and calculation of sediment transport over three modal beach types presented here shows that the original conceptual ideas and field data regarding aeolian sediment transport are correct. Dissipative beaches show the greatest long term potential for sediment delivery to the backshore whilst reflective beaches display the least, with a trend from relatively high to low in the intermediate beach state range. [ABSTRACT FROM AUTHOR]

Al-Nasrawi, A.K.M.; Jones, B.G., and Hamylton, S. M., 2016. GIS-based modelling of vulnerability of coastal wetland ecosystems to environmental changes: Comerong Island, southeastern Australia. 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. 33-37. Coconut Creek (Florida), ISSN 0749-0208. Sustainable management of coastal zones has become a complicated issue. The majority of the human population lives along the coast, where their activities, together with a range of environmental changes, have altered the natural ecosystem processes and caused changes in coastal wetlands. To ensure sustainable use of coastal resources, a comprehensive set of modelling tools can help managers to make decisions. This study uses Comerong Island (southeastern NSW, Australia) as a case study to demonstrate the importance of modelling modifications to environmental change. Several data-based modelling approaches are employed to explore how human activities have altered this estuarine island setting over the last sixty years (1949 - 2014). Multi-temporal changes in land cover, shorelines and sediment delivery are estimated from remote sensing data, GIS analysis, and laboratory tests on water and sediment samples (grain size, X-ray diffraction and loss on ignition and water analysis). Results show there are significant changes to the areal extents and elevation of mangroves, saltmarshes and shorelines in the wetlands on Comerong Island over the time period of analysis, including northern accretion (0.4 km2), eastern, middle and southern erosion (0.7 km2) of the island. The implementation of modelling using GIS tools, water and sediment samples to monitor ecosystem processes, such as sediment transport and erosion/deposition, will allow resource managers to make more informed decisions by evaluating the potential consequences of the existing situation. [ABSTRACT FROM AUTHOR]

Fang, J.Y.; Chen, Y.P.; Yao, P., and Su, M., 2016. Effective Roughness Height in High-Concentrated Flows. 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. 33-37. Coconut Creek (Florida), ISSN 0749-0208. The effective roughness height is an important parameter in coastal sediment transport models. It has been extensively investigated in the past but few research results are related to the high-concentrated flows which often occur in a silty coast. A series of experiments has been carried out in a wave-current flume with silt-sized sediment bed. The mean velocity profiles were measured under different combined wave-current conditions. The effective roughness heights were calculated based on the curve fitting of measured velocity profiles by following the velocity profile model of You (1994). The accuracy of three empirical models, namely, Grant and Madsen (1982), Li and Amos (1998) and You (1996) was examined with the 'measured' effective roughness heights. The results show that all the models are not much accurate for the high-concentrated flows, particularly in the case with a relatively small sediment size. Therefore, cautions should be taken when applying those models in the silty coast, particularly during the extreme events. [ABSTRACT FROM AUTHOR]

Choi, B.H.; Yuk, J.-H., and Kim, K.O., 2016. Integral tide-surge-wave model of the Yellow Sea for understanding local 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. 208-212. Coconut Creek (Florida), ISSN 0749-0208. Numerical simulations of tide and tidal current for the effect of the new port on Saemangeum area were carried out based on finely resolved meshes and integral tide-surge-wave model of the whole Yellow Sea and also for a compact model optimized for the field operation. The resulting modelling system can be used for hindcasting (prediction) the tide-surge-wave coupled environments at complex coastline, shallow water and fine-grained sediment area like areas around Korean Peninsula. We investigated and discussed the changes of tidal residual current, maximum bottom shear stress and tidal energy dissipation due to the new port for Saemangeum area where the construction of new large port is being built. [ABSTRACT FROM AUTHOR]

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]

Schwarzer, K.; Nguyen Cong Thanh and Ricklefs, K., 2016. Sediment re-deposition in the mangrove environment of Can Gio, Saigon River estuary (Vietnam). 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. 138-142. Coconut Creek (Florida), ISSN 0749-0208. Sediment re-deposition in mangrove environments is usually attributed to marine and estuarine hydrodynamics - rainfall as a driver was not considered yet. However, combined with annual water level variations, tropical rainfall can play a significant role for sediment re-deposition. Inside mangroves, current velocities induced by rainwater runoff during low tide conditions can be much stronger than tide-induced currents. Along the Saigon River Estuary and the Mekong Delta coastline, rainfall is high from May to October and low from December to April. To study processes controlling sediment re-deposition, data of current and suspended matter concentration have been combined with sediment re-deposition rates. All investigations have been carried out in the Can Gio mangrove reserve, Saigon River mouth. Based on a 19-year data set (1991 - 2009), strong annual variability in water level heights and tidal range are observed, with a mean maximum high tide level of 3.34 m during the rainy season and 3.73 m at the beginning of the dry season. Maximum tidal range is reached during the rainy season coinciding with the lowest annual average sea level. The highest parts of the mangrove forest are not inundated by tides during these periods. Only heavy rainfall during these times can lead to mangrove soil mobilisation, induce strong currents between the mangrove roots and cause erosional gullies. Depending on the amount of precipitation, this sediment mobilisation and the amount of suspension load in the forest can be much stronger than sediment transport induced by tidal currents. [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]

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]

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]

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]

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]

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]

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]

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]

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]

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]