Carvalho, A.M.C.; Ellis, J.T.; Lamothe, M., and Maia, L.P., 2016. Using wind direction and shoreline morphology to model sand dune mobilization.

This paper aims to establish a relationship between wind direction, shoreline position, and aeolian transport directions. Ceará State in NE Brazil, which mainly comprises barchans, barchanoids, parabolic dunes, and large flattened composed dunes was used to formulate and test a dune transport model that can be applied to north and east facing beaches. The headland-bay beaches of Ceará progressively increase in angle from E to W. This is accompanied by a corresponding change in the near-beach dune migration direction. A significant change in the wind pattern for the northern portion of Ceará was found, which resulted in a shift in dune migration from E-W to ENE-WSW as the shoreline orientation changed from NW-SE to W-E. The different aeolian transport conditions along the stretches of the headland-bay beach gradually shifted from transport parallel to the shoreline to unimpeded aeolian transport that moves sediments inland. Beach feeding occurs from headland bypass as dunes occupy the area landward of the headland. A zone of composite wind transport directions, winds carrying sand directly from the beach and those transporting sediment landward of the headland, was identified. This variation of wind transport conditions is confirmed by the dune morphology and influenced by the relationship between shoreline position and wind angle approach. The proposed model uses the sine of the angle between wind direction and shoreline orientation to predict aeolian transport and determines the volume of sediment transported by the wind. This model identifies stretches of shoreline under different aeolian transport directions and exhibits compatibility with measured dune migration.

Nolan, C.B.; Tufford, D.L., and Chalcraft, D.R., 2016. Needs assessment of coastal land managers for drought onset indicators in the southeastern United States.

The ability to detect the onset of drought is important to coastal resource managers because the knowledge enhances preparedness and mitigation. Existing drought indicators, however, were generally designed with agricultural, hydrological, meteorological, socio-economic, or wildfire management in mind and generally quantify deficits in freshwater availability. It is unclear whether coastal resource managers find existing indicators adequate for managing coastal resources and, if not, what information would be most useful to manage resources under threat of drought. A needs assessment was conducted with 30 land managers and natural resource specialists of the coastal Carolinas region to enhance the understanding of drought indicators and to comprehend the indicators' utility for managing coastal natural resources. Eighty-three percent of participants believed that early drought detection was important for their management efforts, yet only 33% were aware of existing drought indicators. Half of the participants stated that drought indicators needed to be specifically focused on a particular kind of habitat, but 90% thought that a single index could be useful for multiple coastal habitats with broad similarities. All participants who stated a current need for an early-warning drought indicator (83%) emphasized indicator parameters that reflected both freshwater availability and impacts on ecological resources, but 86% of the participants indicated that they may not have the resources to collect such data. The results revealed common priorities and concerns among coastal resource managers and exposed opportunities to incorporate parameters of shared interest into a drought indicator tailored to the early detection of drought through the inclusion of ecological parameters.

Guégan, E.; Sinitsyn, A.; Kokin, O., and Ogorodov, S., 2016. Coastal geomorphology and ground thermal regime of the Varandey area, northern Russia.

This study documents a regional summary of the present geomorphology of the Varandey area coastline of northern Russia. Fieldwork was undertaken over three seasons (2011–2013) and combined with observations from 1999. The Varandey area has morphologies varying from low-gradient, wide sandy shores with dune belts that reflect stable and aggrading coasts (where sandy shore processes govern the coastal dynamics) to subvertical coastal ice-rich bluffs and narrow beaches, which reveal active coastal recession (where cohesive shore processes are dominant). In addition to these geomorphological observations, the study documents a continuous ground temperature recorded from July 2011 through August 2013 by six thermistor strings installed on a 500-m-long transect perpendicular to the coast. The thermal regime of the ground in permafrost areas controls its mechanical strength and stability, therefore influencing the coastal dynamics through a recession caused by a thawing bluff failure (thermodenudation). The ground temperature recorded along the transect varied from −1.9°C at the thermistor strings located 500 m from the shoreline to 0.3°C at the thermistor strings situated on the upper beach. The temperature measurements characterize this area as being affected by a warm permafrost near the temperature phase change (transient conditions), and the stability of the ice-rich segment of this coastline is sensitive to future variations of air temperature. Our investigation did not reveal permafrost underneath the upper beach of the thermally investigated section and did identify numerous cryopegs in the inland portion.

Schultz, M.T. and Smith, E.R., 2016. Assessing the resilience of coastal systems: A probabilistic approach.

Resilience is the ability to anticipate, prepare for, and adapt to changing conditions and withstand, respond to, and recover rapidly from disruptions. Methods and tools to quantify resilience are needed to provide actionable intelligence to plan, design, construct, and manage coastal systems. This paper describes how a probabilistic measure of resilience can be assessed for a coastal community using a Bayesian network. The measure of resilience is the joint probability of meeting two management objectives, one with respect to the level of system performance and the other with respect to the length of time required to restore system performance. This paper describes a pilot study to demonstrate the approach in Jamaica Bay, New York, a dense, urban, residential community located on the southern coast of Long Island. Results of the pilot study illustrate how practical information can be developed to support decisions about managing coastal systems. The pilot study provides insights into data and information requirements; the advantages, challenges, and limitations of the approach; and the feasibility of implementing this approach for operations. This approach to resilience assessment is well suited for coastal planning contexts because it explicitly incorporates information about uncertainty in the severity of coastal storm events, as well as uncertainty in how the system will perform when exposed to storm loads. The method challenges the community to establish explicit objectives for coastal resilience, identifies what data are needed to monitor progress toward objectives, and provides a platform from which to explore how those objectives might be achieved in practice.

Menéndez, M.C.; Delgado, A.L.; Berasategui, A.A.; Piccolo, M.C., and Hoffmeyer, M.S., 2016. Seasonal and tidal dynamics of water temperature, salinity, chlorophyll-a, suspended particulate matter, particulate organic matter, and zooplankton abundance in a shallow, mixed estuary (Bahía Blanca, Argentina).

Estuaries are characterized by a variety of interrelated, abiotic and biotic, structural components and intensive physical, chemical, and biological processes. The aim of this study was to investigate the seasonal- and tidal-mediated variability in water temperature, salinity, suspended particulate matter (SPM), particulate organic matter (POM), chlorophyll-a (Chl-a), and zooplankton abundance in the Bahía Blanca estuary, Argentina. The underlying mechanisms responsible for the observed variability are also discussed. Sampling was carried out every two months (December 2004–April 2006) during 14-h tidal cycles in a fixed station located in the inner zone of the estuary. Vertical profiles of temperature and salinity and water samples were obtained at the surface and the bottom to determine SPM, POM, Chl-a, and zooplankton. SPM (97.3 ± 6.9 mg L⁻¹) showed a strong seasonality, mainly attributed to biological activity. POM concentration (1539 ± 107.6 mgC m⁻¹) was high, possibly derived from vascular plants and benthic microalgae. Chl-a (6.91 ± 0.73 mg m⁻³) and zooplankton (2024.23 ± 9.16 individuals m⁻³) also showed a seasonal pattern, with higher concentrations in the summer. During the tidal cycle, the highest amounts of the measured variables were observed during the ebb tide. The results highlight the strong variability in the physicochemical and biological variables at different time scales in mesotidal, temperate estuaries. It is essential to take into account this variability in any monitoring program performed in a temperate system dominated by such a tidal regime.

Ward, R.D.; Burnside, N.G.; Joyce, C.B., and Sepp, K., 2016. Importance of microtopography in determining plant community distribution in Baltic coastal wetlands.

This study investigated microtopography and edaphic factors to ascertain their use as determinants for identifying the location and extent of plant community types in internationally important Baltic coastal wetlands in Estonia. Plant community types were identified, and abundance and frequency of plant species were recorded within 105 1-m² quadrats at two sites. Within each quadrat, a real-time kinematic differential GPS (dGPS) was used to record elevation; soil moisture, organic matter, particle size, pH, salinity, nitrogen (N), phosphorus (P), and potassium (K) were also measured. A significant difference was recorded for elevation in six of the seven different plant communities: Reed Swamp, Clubrush Swamp, Lower Shore grassland, Upper Shore grassland, Tall Grassland, and Scrub and Developing Woodland. Median elevation differences between plant communities were between 0.04 m and 0.19 m. Soil moisture and salinity were related to elevation, and all three significantly influenced plant community location. A Canonical Correspondence Analysis confirmed that elevation and soil moisture influenced the distribution of five of the seven community types, while the remaining two communities were strongly related to either pH and salinity or organic matter, N, and K, respectively. Microtopography was found to strongly affect the distribution and extent of Baltic coastal wetland plant communities because of the relationship between sea-level and site hydrology. Rising sea levels may profoundly affect the distribution of plant communities in these wetlands, and the quantification of the elevation differences between the plant communities in this study provides an important baseline for predicting their future location and extent.

Schoeman, K.; Van der Merwe, P., and Slabbert, E., 2016. The perceived value of a scuba diving experience.

Tourists today are more value conscious, which creates challenges for tourism products to keep up with what tourists want and how they perceive certain experiences. Perceived tourism value can be seen as the value that tourists experience and can be defined from separate perspectives, such as money, quality, benefits, and social aspects. The purpose of this study is to determine the perceived value of a scuba diving experience. A survey was conducted at Sodwana Bay, where 402 divers participated by means of stratified sampling. The factor analysis revealed five values, namely perceived emotional value, perceived risk value, perceived functional value, perceived social value, and perceived epistemic value. This insight can assist role players in the marine environment to adapt their scuba diving product where needed and can also assist in the improvement of diver satisfaction, the diving experience, and marketing initiatives.

Li, D.-W.; Chen, J.-F.; Wang, K.; Li, H.-L.; Gao, S.-Q.; Jin, H.-Y.; Xu, J.; Huang, D.-J., and Weng, H.-X., 2016. Contribution of outer-shelf deep water to the nutrient inventories in the euphotic zone of the Changjiang River plume during summer.

The nutrient supply to the euphotic zone of high-productivity areas in the Changjiang Estuary is crucial to understanding ecological processes. Previous studies suggested that Changjiang Diluted Water (CDW) and Outer-Shelf Deep Water (ODW) are the two main sources for nutrient supply, while a quantitative estimate of each nutrient species to the euphotic zone remains unknown. Based on a field survey and an end-member mixing model, the nutrient inventories of ODW and its contribution to the model-predicted nutrient inventory in the euphotic zone of the Changjiang River plume–impacted area were assessed. Upwelling of ODW was identified, indicating that it significantly contributed to nutrient inventories in the upper layer. The nutrient inventory estimate suggested that the area-integrated nutrient inventories of ODW were higher than those of CDW in the euphotic zone of the plume-impacted area. As inferred from the mixing model, the contributions of ODW to the dissolved inorganic nitrogen (contains nitrate, nitrite, and ammonia)and silicate inventories in the euphotic zone were 18.2% and 28.1%, respectively, much lower than those of CDW. However, 37.6% and 39.1% of the phosphate inventory were from ODW and CDW, respectively, indicating that ODW phosphate contribution was comparable with that of CDW in the euphotic zone.

Zhang, Y.; Jeng, D.-S.; Zhao, H.Y., and Zhang J.-S., 2016. Numerical modelling of pore pressure accumulations in marine sediments around submerged breakwaters under combined wave and current loadings.

In this study, an integrated model for the wave (current)-induced seabed response around submerged breakwaters is proposed. The Reynolds-Averaged Navier-Stokes (RANS) equations and k − ϵ turbulence model were used for the flow field, whereas an inelastic two-dimensional seabed model was used for pore pressure accumulation in a porous seabed. Unlike previous studies, the residual soil response was considered in the present model, together with the interaction between waves and currents and the preconsolidation process. The present model was validated with previous studies for wave–current interaction model and seabed models. Based on the numerical examples presented, the following conclusions were made: (1) preconsolidation because of static loading of breakwaters and static water pressures significantly affects the seabed response around the breakwaters, (2) the liquefaction depth under combined wave and current loading is less than that under wave-only loading, (3) the maximum liquefaction depth increases as the width and height of the submerged breakwater increase, and (4) liquefaction depth for the submerged, multiple breakwaters is smaller than that for a single, submerged breakwater.

Cui, Z.; Schulz-Bull, D.E.; Hou, Y.; Xia, Z., and Waniek, J.J., 2016. Geochemical characteristics and provenance of Holocene sediments (core STAT22) in the Beibu Gulf, South China Sea.

Geochemical investigations of the core sediments STAT22 from the Beibu Gulf, South China Sea, were carried out to understand the provenance of the Holocene sediments. Geochemical indices of La/Co, La/Sc, and Zr/Ti ratios, combined with distribution patterns of rare earth elements, suggest that the western Hainan Island was the main provenance of the core sediments. The eastern Qiongzhou Strait was also an important source of the sediments at the core location, but its contributions varied spatially and temporally with strait formation and evolution. With the opening of the Qiongzhou Strait, the provenance and hydrodynamic conditions of the Beibu Gulf underwent a significant change. Around 4500 YBP, the materials from the eastern area of the Qiongzhou Strait were transported into the study area and hence became one of the important sources for the core sediments. In contrast, Red River contributed little to the core sediments during the entire Holocene. Thus, with sea-level fluctuation, the depositional environment in the Beibu Gulf significantly changed during the Holocene.

Linhoss, A.C. and Underwood, W.V., 2016. Modeling salt panne land-cover suitability under sea-level rise.

Salt pannes are an ecologically important but poorly understood feature of the salt marsh environments. Like all coastal marshes, salt pannes are threatened by sea-level rise; therefore, it is important to assess how they will be affected by rising seas. Because of a lack of understanding regarding salt panne formation and the possibly stochastic nature of their development, a traditional and purely deterministic modeling approach is unsuitable for assessing the impacts of sea-level rise on salt pannes. This research used a combination of deterministic and stochastic models to simulate the land-cover suitability for salt pannes in the Grand Bay National Estuarine Research Reserve, Mississippi, under five sea-level rise scenarios, including a rise of 0.25, 0.5, 1.0, 1.5, and 2.0 m by 2100. The Sea-Level Affecting Marshes Model (SLAMM) simulated general land-cover at the study site. However, SLAMM does not include capabilities for specifically simulating salt panne land-cover. As such, MaxEnt used the results from SLAMM, along with other environmental variables, to specifically simulate the spatial suitability for salt panne land-cover. The results showed that the total wetland and upland areas are predicted to consistently decrease under increasing rates of sea-level rise. However, because of elevation plateaus in the study site, the area of land-cover specifically suitable for salt pannes does not follow the same pattern. The primary environmental driver of salt panne land-cover suitability is elevation, followed by topographic depressional areas. Land cover contributes very little to the model results. This novel use of a land-cover suitability model has important potential for being applied to additional studies to investigate drivers of land-cover change, identify transitional areas, and examine land-cover fitness under competition.

Kaveh, N.A.; Ghaheri, A.; Chegini, V., and Nazarali, M., 2016. Application of a hybrid approach for tide-surge modeling in the Persian Gulf.

In this study a tide-surge model of the Persian Gulf area has been developed using an unstructured grid, Finite-Volume Coastal Ocean Model (FVCOM). The model used European Centre for Medium-Range Weather Forecasts Re-Analysis Interim wind field and atmospheric pressure forcings and the water level boundary condition derived from global ocean tide model TPXO 7.1. Postprocessing of the water level predictions in a coastal station was conducted by applying the back-propagation artificial neural network technique. This method was used to improve surge predictions of the hydrodynamic model in the region. The input factors of the network consist of all possible combinations of numerical model surge prediction, wind components and duration, and sea-level pressure anomaly. In order to select the best prediction model, all these parameters were tested and compared with observed surge heights. It was concluded that mean sea-level pressure anomaly is the main affecting input parameter to have the best surge prediction. The combination of all input parameters resulted in surge predictions with a skill factor of 94.82% vs. 90.86%, which is the FVCOM numerical model result. It was shown that excluding numerical model surge predictions will greatly reduce the accuracy of surge height predictions.

Hou, G.-J.; Luan, X.; Song, D.-L., and Ma, X.-Y., 2016. Underwater mad-made object recognition on the basis of color and shape features.

In complex underwater situations, how to realize object extraction accurately and effectively is the key technology of underwater object recognition. In this paper, the detection and recognition techniques of underwater man-made objects on the basis of color and shape features have been studied in depth. First, the objects of interest in an underwater image are extracted by applying a color-based algorithm. Then an improved two-dimensional Otsu algorithm is utilized for removing the background color noise. To recognize the shape type of a regular object, a robust algorithm based on shape signature is presented. The experimental results show that the proposed approach is effective and robust, such as an acceptable extraction rate (exceeding 80%) of the object of interest, an ideal outcome of background color noise removal, high accurate shape of the object's edge, and a good average recognition rate of shape type (approximately 90%). It proves that this algorithm can accurately settle the problem of object extraction and recognition under different cases of distance, angle, and illumination.

Noor, N.; Shaukat, S.S., and Naseem, S., 2016. Evaluation of elemental composition of Avicennia marina and associated soil, Karachi coast, Pakistan.

The present study evaluates the elemental composition of root, stems, and leaves of Avicennia marina and related soil samples. The scanning electron microscope–energy dispersive spectrometer (SEM-EDS) technique along with wet chemical analysis was used for the determination of elemental composition and their ratios in vegetative parts of A. marina. The SEM of soil samples displays clay minerals having platy structure and well-rounded quartz mineral. The EDS spectra of soil represented an O>Si>Al>Ca>Mg>Fe>Na>K>Cl>Ti trend. The Al and Si in spectra confirm the presence of clays, whereas Ti and Fe indicate Ti-bearing mineral (ilmenite). Soil textural study shows that the soil is loamy sand. The wet chemical analysis of all three parts, viz. root, stems, and leaves of A. marina, follow the Na >K >Ca² >Mg² trend. Roots accumulate more K (X̄ 12.6%) than stems (X̄ 6.9%) and leaves (5.0%), whereas stems of A. marina showed highest concentration of Ca² (X̄ 6.03%). The correlation matrix displayed antipathetic relationship among Na –Mg² (−0.911) and K –Mg² (−0.84) in the stems. Leaves exhibit maximum Na and Mg² accumulation, whereas stems possess their minimum concentration. High Na concentrations in leaves indicate that A. marina is a salt-secretor mangrove and can be treated for phytoremediation of salt-affected lands. A strong negative relationship (−0.996) exists between K and Mg² , whereas poor correlations were found among Na and other three macroelements (K , Ca² , and Mg² ) in leaves. The K /Na ratio is in the order of root>stems>leaves, whereas Ca² /Na and Mg² /Na ratios in A. marina followed stems>root>leaves and leaves>root>stems trends respectively. The overall highest sodium bioconcentration factor is responsible for osmoregulation and water transport from soil to plant parts. The EDS elemental composition was compared with wet chemical analysis and found compatible with each other, with few exceptions. Elements exhibit a Na >K >Ca² >Mg² trend through both techniques. EDS elemental mapping shows the distribution of elements in the stems.

Chiu, S., and Small, C., 2016. Observations of cyclone-induced storm surge in coastal Bangladesh.

Water-level measurements from 15 tide gauges in the coastal zone of Bangladesh are analyzed in conjunction with cyclone tracks and wind speed data for 54 cyclones between 1977 and 2010. Storm-surge magnitude is inferred from residual water levels computed by subtracting modeled astronomical tides from observed water levels at each station. Observed residual water levels are generally smaller than reported storm-surge levels for cyclones where both are available, and many cyclones produce no obvious residual at all. Both maximum and minimum residual water levels are higher for west-landing cyclones producing onshore winds and generally diminish for cyclones making landfall on the Bangladesh coast or eastward producing offshore winds. Water levels observed during cyclones are generally more strongly influenced by tidal phase and amplitude than by storm surge alone. In only 7 of the 15 stations does the highest plausible observed water level coincide with a cyclone. Whereas cyclone-coincident residual water-level maxima occur at a wide range of tidal phases, very few coincide with high spring tides. Comparisons of cyclone-related casualties with maximum wind speed, hour of landfall, population density, and residual water level (inferred storm surge) show no significant correlations for any single characteristic. Cyclones with high casualties are often extreme in one or more of these characteristics but there appears to be no single extreme characteristic shared by all high-casualty cyclones.

Montoya, L.H. and Dally, W.R., 2016. Analysis of a 10-year record of nearshore directional wave spectra and implications to littoral processes research and engineering practice.

Slightly more than 10 years (August 28, 2001, to October 28, 2011) of high-resolution directional wave spectra were measured by an Acoustic Doppler Current Profiler installed in the nearshore at Spessard Holland North Beach Park in Melbourne Beach, Florida. Analysis of the record yields an average wave power of 17.6 MW/m of shoreline but with a standard deviation of 22.5 MW/m. Cumulative annual wave power ranged from 43,455 to 93,722 MWh/m, and the annual storm count was between 3 and 14. The mean spectrum for the entire record shows an almost symmetric directional distribution of wave energy centered on the shore-normal direction, which is somewhat unexpected considering that the net longshore transport in the region is definitively N-S. Partitioning the data into shore-normal, NE, and SE windows shows that most wave energy approaches from the SE, again contrary to expectations. The rigorously integrated mean longshore forcing of wave radiation stress, S_xy, is slightly N-S (7.2 N/m) but has a standard deviation of 77.2 N/m. Computing a cumulative average through the record indicates that it takes between 4 and 5 years for the net magnitude and direction of S_xy to be conclusively revealed. Using significant wave height, peak wave period, and mean wave direction to estimate S_xy yields values nominally 42% greater than the integrated results, confirming that fully directional spectra should be used in both study of littoral processes and coastal engineering practice. Finally, the supposition that the wind plays an important role in driving longshore currents and consequently longshore transport is tested. However, analysis of more than 4 years of wind data collected at the site reveals a mean longshore wind stress that is essentially balanced (i.e. nil).

Piña-García, F.; Pereda-García, R.; de Luis-Ruiz, J.M.; Pérez-Álvarez, R., and Husillos-Rodríguez, R., 2016. Determination of geometry and measurement of maritime–terrestrial lines by means of fractals: Application to the coast of Cantabria (Spain).

Zoning of the coast is conditioned by a series of lines and areas that are defined by current legislation. These lines and areas are difficult to be visualized because their definitions correspond to natural phenomena or to characteristics whose representation by means of a Euclidean definition generates, because of their complexity, an uncertainty which depends on the resolution aimed, because the geometry of nature is more fractal than Euclidean. Definitions of coastal lines and zones were analyzed in this work, emphasizing the most suitable method for demarcation in each case and considering both the supranational and national legislations. In addition, fractal geometry was applied to determine the geometry and measurements of maritime–terrestrial lines. The primary methodologies, Compass and Box-Counting, were used to calculate the fractal dimension of the coast of Cantabria (Spain). After meticulous research of various hypotheses that could be proposed, several adjustments with different resolutions were developed, verifying a reduction in the uncertainty. Finally, a fractal dimension for the coast of Cantabria was determined to be 1.19 on orthoimages with a pixel size of 0.25 m. The definition of a length of coast requires a parameter, such as the level of resolution or the fractal dimension, which are not usually provided, and fractal dimensions tend to increase as the resolution decreases. These facts justify the results obtained by this research for the coast of Cantabria.

Zhao, D.; Guo, C., and Su, Y., 2016. Hydrodynamic performance of ichthyoid rudder at different rudder angle settings.

This paper presents the first calculation of the open-water hydrodynamic performance of ordinary and ichthyoid rudders in a viscous flow field using the computational fluid dynamics method as well as an investigation of the lift and resistance coefficients of the two rudders. First, an ichthyoid rudder was formed by adjusting the shape of an ordinary rudder to mimic the shape of a fish tail. Subsequently, open-water tests of ordinary and ichthyoid rudders were conducted, and the maneuverability of the two rudders was compared at different rudder angle settings. The results of the theoretical calculations show that the ichthyoid rudder has obvious advantages over the ordinary rudder in improving the lift coefficient and postponing the stall phenomenon at greater critical rudder angles. This paper also presents calculations of the force and moment of the two rudders at different rudder angle settings and compares the results of these calculations. By comparing the wake fields of the two rudders at different rudder angle settings, our study provides a theoretical basis for the improved ship maneuverability observed with the ichthyoid rudder.

Williams, A.T.; Giardino, A., and Pranzini, E., 2016. Canons of coastal engineering in the United Kingdom: Seawalls/groynes, a century of change?

A Royal Commission on Coast Erosion and Afforestation, 1911, investigated the state of coastal erosion and the resulting protection measures carried out in the U.K. This paper looks at progress undertaken with respect to seawall and groyne protection in the more than 100 years since publication of the report. Seawall design has been greatly modified, although curved and stepped designs were built in the Victorian era, as well as the more common vertical ones. Groynes have also been modified from invariably using wood and rock to other materials, e.g., metal, concrete precast elements, geotextiles, as well as shape, e.g., Y, gamma, or T shaped groynes rather than orthogonal to the beach. Numerical/physical modelling has now made both structures much more robust and rigorous, although arguments are still ongoing regarding how they are used. A strong environmental concern and the need to maintain the beach for recreation characterize most present day projects and are factors that were considered but spasmodically a century ago. These factors favoured new solutions from submerged structures to beach nourishment, which limit the leading role of the seawall/groyne structures used 100 years ago.

Akter, J.; Sarker, M.H.; Popescu, I., and Roelvink, D., 2016. Evolution of the Bengal Delta and its prevailing processes.

Bangladesh, occupying low-lying floodplains and tidal plains, has one of the largest and the most disaster-prone populous deltas in the world. The Bengal Delta is a tide-dominated delta, where tides play the key role in the sediment dispersal process and in shaping the delta. There are many studies and reports on river-dominated deltas, but research is sparse on tide-dominated deltas. The Ganges and Brahmaputra Rivers, which combined form one of the three largest riverine sources of water and sediment for the world's oceans, have developed the Bengal Delta to its present form with an aerial extent of 10⁴ km². About 10¹² m³ of water with 10⁹ tonnes of sediment per year make this system morphologically active. In the last five decades, the Bengal Delta has prograded at a rate of 17 km²/y, whereas most large deltas elsewhere in the world suffered from sediment starvation. Delta progradation always makes the river system unstable, and rapid changes cause the delta to become dynamic. Sea level rise induced by unequivocal climate change and subsidence would make the delta more vulnerable in the coming decades. Although some literature is available on the millennium-scale development process of the Bengal Delta, sound knowledge on the decade- to century-scale processes of the delta development for facing the threats of climate change and deltaic subsidence is limited. In addition, there are significant differences in opinions and widely varying findings in the literature to the response of the delta to different natural and human interventions. Against this backdrop, relevant available literature on Bengal Delta and deltas elsewhere in the world, is reviewed and evaluated to provide direction for future research that would help to form a way out of the present situation and a way into sustainable planning for this delta.

Rapizo, H.; d'Avila, V.; Violante-Carvalho, N.; Pinho, U.; Parente C.E., and Nascimento, F., 2016. Simple techniques for retrieval of wind wave periods and directions from optical images sequences in wave tanks.

Optical techniques are potentially suitable for overcoming some of the limitations faced by single-point sensors, like buoys, in retrieving spatial properties of wind-generated waves. However, most of the approaches that have been addressed in the literature employ complex configurations that use a coupling system between cameras, making its implementation difficult. This article describes simple techniques for measuring the period and direction of multimodal, regular waves, employing a single, commonly available camera. Furthermore, there is no special requirement for light conditions, making its implementation feasible, in both indoor and outdoor environments. Several tests were conducted in a multidirectional tank, varying the steepness and direction of the waves. The optical measurements were in good agreement, especially for waves from moderate to greater steepness. The techniques described here could be employed as a preliminary step before tackling more-complex configurations, for instance, as a priori information on the main wave modes.

Fan, A.; Yan, X., and Yin, Q., 2016. A multisource information system for monitoring and improving ship energy efficiency.

Global climate change has attracted an increasing amount of attention by the public. The shipping industry is being scrutinized with regard to improving efficiency and reducing emissions. This paper explores the monitoring technology and efficiency enhancement method for a ship. First, the internal and external factors that affect a ship's energy efficiency are determined and examined. Second, an inland river ship is selected as a research target on which a multisource information system is constructed via the selection and installation of the corresponding sensors on the ship. A series of system tests have also been performed when the ship is in operation. The field tests prove that the established system is adequate for the voyage and that all of the sensors can normally monitor the parameters. In addition, a massive quantity of data for the upper, middle, and lower reaches of the Yangtze River are obtained. A grey correlation analysis and regional difference analysis are conducted using these data. The analysis results suggest that the main engine speed has the greatest effect on a ship's fuel consumption and that the voyage environment of the Yangtze River affects a ship's fuel consumption. Finally, a novel ship speed-optimization method that considers the impact of voyage environment is proposed as an energy efficiency enhancement example. This study not only aids shipping companies and ship officers in monitoring a ship's operations but also provides a high-energy efficiency strategy for a ship's operation.