Almeida, P.M.M.; Cruz, C.B.M.; Amaral, F.G.; Furtado, L.F.A.; Duarte, G.S.; Silva, G.F.; Barros, R.S.; Marques, J.V.F.P.A.; Rosário, E.S.; Santos, V.F.; Alves, A.; Chaves, F.O., and Soares, M.L.G., 2020. Mangrove typology: A proposal for mapping based on high spatial resolution orbital remote sensing. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1-5. Coconut Creek (Florida), ISSN 0749-0208.

Solutions to improve environmental management strategies increasingly require the adoption of new techniques, such as Geotechnologies. All this effort must be carried out in a multidisciplinary way, using different concepts, techniques and scientific visions about the same phenomenon. In response to the cartographic demands, one of the primordial steps for a good mapping starts before the processing of the images to be used. This step is based on the definition of a legend related to the scale and purpose of the mapping. This work aims to contribute in the definition of a typology adapted to the use of high spatial resolution remote sensing data for the mapping of mangrove phytophysiognomies in the Brazilian Equatorial Coast. The final mapping covered more than 27,000 ha of forests divided into the following classes: (i) Forest dominated by Avicennia schaueriana; (ii) Forest dominated by Rhizophora spp.; (iii) Mixed Forests; all indicating differences in structural development (high, medium or low). Through this reflexive process, this work contributes to the mapping with effectively transdisciplinary strategies.

Leite, A.A.C.; Queiroz, A.F.S.; Morais, L.M.S.; Azevedo, C.C., and Martinelli Filho, J.E., 2020. Zooplankton at the Northern Brazilian Coast: Evaluation and gaps. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 12–17. Coconut Creek (Florida), ISSN 0749-0208.

Research on planktonic communities in the Brazilian Northern coast started since the XIX century by foreigners, most of it being taxonomical surveys. The only literature reviews for the area are a technical report and a book chapter published in Portuguese by 2005. This article aimed to analyze the existing literature about zooplanktonic communities at the Northern coast of Brazil from a decade after the last review (2005 to 2015), to update and elucidate possible knowledge patterns and identify existing gaps. The bibliographic review considered the three states of the Brazilian North coast (Maranhão, Pará and Amapá), in the libraries of educational and research institutions, indexing platforms and databases on the internet (Web of Knowledge, Scopus, Scielo and Google Scholar). The most important parameters extracted from the publications were: year and language of publication, zooplankton density, dominant species, sampling mesh size, study area (by state), type of publication, coordinates, and research subject. A total of 222 publications were found, 45 (20.3%) referred to white publications (national and international scientific articles) and 177 (79.7%) referred to gray literature (do not published by peer review system). The Pará state showed a higher number of publications than Amapá and Maranhão sates together. The publications were mostly about zooplanktonic community description, copepod ecology and taxonomy or experimental approaches, and sampling took place mostly on estuarine environments (87.5%). Richness varied from 4 to 68 taxa, while density varied from 0.01 to 962,400 org.m^-3. Despite the numerous research in the period, there are important knowledge gaps, mainly in relation to collection sites, target organisms, and research subjects. Future research should focus primarily on oceanic areas (outer shelf) and on themes such as experimental ecology, biogeochemistry and long temporal scale surveys, so that a more comprehensive knowledge about zooplankton on the Brazilian Northern coast can be achieved.

Balas, L.; Genc, A.N., and Eser, E., 2020. Transitional waters typology in Turkey: Melen Estuary case study. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 18-22. Coconut Creek (Florida), ISSN 0749-0208.

Transitional and coastal water bodies are dynamic and complex environments. Even though widespread typological descriptors have been defined for coastal waters, typology studies for transitional waters are still continuing in Turkey as in many European countries. Transitional waters include estuaries, lagoons, and deltas. In this manuscript, the typology study applied for the Melen estuary is presented. Melen Estuary located in the Western Black Sea Part of Turkey is one of the significant watersheds of Turkey as it supplies more than 50% of the drinking water to the city of Istanbul. In typology approach, System B is accepted, and the Guidance Document No 5 produced by the Common Implementation Strategy for the Water Framework Directive (2000/60/EC) Working Group 2.4 (COAST) is closely followed. In addition to the obligatory factors, current velocity, wave exposure, and mixing characteristics are investigated as the optional factors. Measurements and modeling studies are used together. The coastal processes in the Melen Estuary are modelled. The wind and wave climate, wind and wave-induced current patterns, and mixing zone are simulated by HYDROTAM-3D (Three dimensional hydrodynamic, transport and water quality model). In the long term directional wind analyses, six hourly predictions of the European Centre for Medium-Range Weather Forecasts (ECMWF) between 2000-2019 are analyzed. In the long term directional wave statistical analysis, six hourly wave predictions of ECMWF between 2000-2019 operational archive are used. The range of significant wave heights, with 12 hours/year exceedance probability, is estimated as 0.4m≤H_s,12≤3.2 m. The wave exposure index for Melen transitional water is calculated. The dominant wave direction interval is determined as North-Northeast. Based on the mixing studies, the degree of stratification is determined as partially stratified.

Burningham, H. and Knight, J. 2020. Biological zonation and bedrock strength on a high energy granite shore platform. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 23-28. Coconut Creek (Florida), ISSN 0749-0208.

Many studies have shown that downwearing of rock shore platforms results from interactions between biological and geomorphological processes, but the relative roles of biological, lithological and external (wave hydraulic action) in shaping rock shore platforms have not been examined in detail. This is important, however, because surface organisms can both increase and decrease rates of platform downwearing by biological weathering and bioprotection, respectively. This study presents biological and geomorphological results from a high energy shoreline in northwest Ireland. Here, the 50-100 m wide granite shore platform has a slope of ∼1:6 and extends from 7-9 m above the level of mean high water springs to ∼2 m below mean low water. Organisms attached to the bedrock surface were surveyed by the quadrat method along two shore-normal topographic transects. At each quadrat site, bedrock hardness was measured using an Equotip instrument. Results show clear ecological zonation that can be directly related to the tidal frame. There is very little evidence for cross-shore changes in bedrock hardness. Elevation is the most significant driving factor for the presence of different species, but bedrock hardness is only associated with the abundance of specific species such as barnacles, demonstrating complexity in biogeomorphological relationships at local scales.

Deng, W.Q.; Zhang, X.; Luo, J.C., and Peng, Y., 2020. South China Sea environment monitoring using remote sensing techniques. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 29–33. Coconut Creek (Florida), ISSN 0749-0208.

As the South China Sea has a wide spatial coverage, remote sensing technology with wide monitoring scope and strong timeliness is increasingly becoming an important means to monitor this part of the ocean. The current monitoring trend is to combine different data sources, including common synthetic aperture radar (SAR), optical image and thermal image by image fusion method, and monitor the marine environment jointly by multiple methods, but there still exist many problems. Using a systematic means of meta-analysis, this paper undertook a literature review about the South China Sea Environment Monitoring with Remote Sensing Techniques, mainly analysing related articles in recent ten years. The current researches show several limitations, thus putting forward a comprehensive multi-angle remote sensing monitoring method is important for ecological and environmental protection in South China Sea.

Gallego-Fernández, J.B.; Morales-Sánchez, J.A.; Martínez, M.L.; García-Franco, J.G., and Zunzunegui, M., 2020. Recovery of beach-foredune vegetation after disturbance by storms. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 34–38. Coconut Creek (Florida), ISSN 0749-0208.

Beaches and foredunes are characterized by being exposed to harsh environmental restrictions mainly due to salt spray, burial by sand and occasional storms. In response to this, plant species from these habitats have adaptations that allow them not only to survive in these environments, but also to recover after the impact of disturbances such as severe storms. In this study, we had the opportunity to study vegetation recovery on the coast of Huelva, Spain, after the impact of a strong winter storm in 2017 which severely affected the vegetation growing on the beach and foredune. Species composition and abundance of vegetation was compared before (2013) and after (2018) the storm hit the coast in 2017. The results show that the effects of the storm were still evident a year later. Native species, mainly perennials, were able to recover almost completely to predisturbance levels. In contrast, the invasive species, Oenothera drummondii, which was abundant before the storm, disappeared from the beach and its presence in the foredune was greatly reduced. Given the forecasts of sea level rise and the increased frequency and intensity of storms, it is necessary to sustain and reinforce the natural coastal sectors where native plant communities maintain the resilience of coastal ecosystems when impacted to these disturbances.

Hamza, A.J.; Esteves, L.S.; Cvitanovic, M., and Kairo, J., 2020. Past and present utilization of mangrove resources in Eastern Africa and drivers of change In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 39–44. Coconut Creek (Florida), ISSN 0749-0208.

Mangroves offer natural coastal protection and are carbon sinks, playing a key role in mitigating climate change impacts. Despite their recognized importance as the main livelihood of many coastal communities in developing countries, mangroves are being lost at fast rates impacting overwhelmingly the poorest people. The pressures of changing climate and human activities urge a better understanding of the drivers leading to mangrove loss and degradation and the effects on coastal communities. A systematic literature search was undertaken to review the current understanding of how mangroves have been used through time in Kenya and identify the key drivers of change. Results from 32 articles identified extraction of wood for construction and fuel as the major use of mangrove in Kenya. Direct needs of mangrove resources are the major cause of changes in the mangrove areas and this is due to lack of harvesting plans. The paper emphasizes the need to identify ways in which changes in mangroves can become opportunities to improve coastal communities living conditions.

Jacob, J.; Correia, C.; Torres, A.F.; Xufre, G.; Matos, A.; Ferreira, C.; Reis, M.P.; Caetano, S.; Freitas, C.S.; Barbosa, A.B., and Cravo, A., 2020. Impacts of decommissioning and upgrading urban wastewater treatment plants on the water quality in a shellfish farming coastal lagoon (Ria Formosa, South Portugal). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 45–50. Coconut Creek (Florida), ISSN 0749-0208.

Ria Formosa is a productive coastal lagoon, located on the south coast of Portugal, and represents the largest national producer of shellfish bivalves (ca. 90% production). This ecosystem is subjected to various anthropogenic pressures, including the discharge of urban wastewater treatment plants (UWWTP), which impacts the lagoon water quality. This study aimed to assess the impact of alterations in the functioning of two UWWTP on the water quality of Ria Formosa, based on chemical variables, phytoplankton composition (including potential harmful species) and faecal contamination. During the period September 2018 - October 2019, water sampling was conducted along dominant longitudinal gradients of the effluent dispersion from the discharge point (1-2 km), for two sites: a decommissioned (OP) and a modified (FO) UWWTP. After modification, the later started receiving a higher influent volume (ca. 40%), under an innovative technology system (biological treatment in aerobic granular sludge). Based on chemical water quality variables, phytoplankton and indicators of faecal contamination, a significant improvement along the longitudinal gradient from the discharge point was observed after OP decommissioning. This improvement was fast, being detected two months after decommissioning, positively affecting areas used as shellfish farming grounds. However, distribution patterns of bacteriological indicators and regular shellfish harvesting interdictions suggested an alternative source of faecal contamination after OP decommissioning. At FO, both chemical variables and bacteriological indicators of faecal contamination revealed a slower improvement, only six-months after the UWWTP alteration. Before that, increased and highly variable ammonium, chlorophyll a concentration, phytoplankton abundances and Escherichia coli densities, revealed an unstable phase. Overall, a lower water quality at FO in respect to OP reflected not only a higher effluent volume but also more restricted water circulation for the former.

Kim, M.-S.; Jang, S.-C.; Lee, S.-H.; Yoon, H.-S., and Park, J.-H., 2020. Spatiotemporal changes in vegetation frontlines on barrier islands in Nakdong River Estuary during the typhoon season. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 51-56. Coconut Creek (Florida), ISSN 0749-0208.

This paper was performed to investigate the spatiotemporal changes in vegetation frontlines on barrier islands in the Nakdong River Estuary using the Differential Global Positioning System (DGPS) field survey. The field survey period occurs during each fall season and included typhoon Kong-Rey (1825) in October 2018and typhoons Lingling (1913), Tapha (1917), and Mitag (1918) in September–October 2019. The results of this paper can be summarized as follows. Along the vegetation frontlines of Jinu-do (Western barrier island), Shinja-do (Central barrier island), and Doyo-deung (Eastern barrier island), erosion and sedimentation phenomena are repeated due to the interaction between ocean waves and coastal debris. Doyo-deung, on the east side of the Nakdong River Estuary, showed the greatest changes in vegetation frontlines, followed by Shinja-do and Jinu-do. The external force of the ocean caused by the typhoon (high waves, high tides) directly affected the inside of the barrier islands, and two types of vegetation frontline retreat were confirmed to have occurred according to the characteristics of the beach profiles.

Lee, T.; Moon, J.-H.; Jung, S.-K.; Park, G.; Kwon, S.; Min, S.-H., and Son, Y.B., 2020. Changes of nutrient budget due to physiochemical factors in the coastal area of Jeju, Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 57–61. Coconut Creek (Florida), ISSN 0749-0208.

In Jeju coastal area which is UNESCO biosphere reserve, there has recently been eutrophication and serious changes in the coastal ecosystem such as coastal fishery decline and green algal bloom. A large amount of nutrients that inflow to the coastal area through the discharge of land-based aquaculture farms (LAFs) and submarine groundwater discharge (SGD) are transported by the tidal current. We established representative area of the Jeju coastal area and calculated the nutrients budget of the LAFs, SGD, primary production (PP), and sediment in this study area. The advection-diffusion equation applied to the model was calculated through the passive tracer experiments. The water mass transport in and out of the study area was estimated by modeling, and the nutrient fluxes was calculated by water volume and nutrient concentration. The nutrient released from the aquaculture farms are primarily determined by the reversing tidal currents along the coast of the study area, showing a narrow band of coast, indicating little cross-isobath nutrient exchange between the nearshore and offshore water. The amount of total carbon (TC), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and dissolved silicon (DSi) influxes into the study area from the LAFs, SGD and offshore were 2,696,282 kg·day^-1, 18,823 kg·day^-1, 3,395 kg·day^-1 and 65,723 kg·day^-1, respectively. The amount of TC, TN, TP and Si outfluxes transported from the study area to the offshore, deposited in the sediment and used for PP were 2,696,274 kg·day^-1, 18,821 kg·day^-1, 3,394 kg·day^-1 and 65,721 kg·day^-1, respectively. In the study area nutrients are accumulating due to inflows more than outflows. The accumulation rate of TC, DIN, DIP and DSi are 2.29 mg·m^-3·day^-1, 0.76 mg·m^-3·day^-1, 0.18 mg·m^-3·day^-1, 1.06 mg·m^-3·day^-1, respectively. The coastal area of Jeju is accumulating nutrients, which could increase coastal pollution such as eutrophication, green algal bloom and whitening.

Li, S.L.; Liu, R.R., and Wang, P., 2020. Optimization of dust-containing rain water percolation system for traffic roads in coastal ecological sponge cities. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 62–66. Coconut Creek (Florida), ISSN 0749-0208.

The traditional method of rain water percolation control model using probability analysis method failed to solve the quantitative relationship between the dusty rain water seepage and runoff and the statistical characteristic of rainfall in the traffic road of sponge city, and the modeling effect was not good. Based on sensor fusion tracking filter, a dust-containing rain water percolation control model for urban traffic in coastal ecological sponge cities is presented in this paper. The idea of fusion tracking filter is adopted to make the control function of rain water percolation control more close to the posterior probability density of water storage energy, which can effectively reflect rain water seepage quantity and planned runoff coefficient of traffic road in sponge city. The control function of rain water percolation control function is closer to the posterior probability density of water storage energy. The fuzzy fusion tracking filter is used to ensure the positive characterization of the covariance matrix of the traffic road dusty rain water percolation planning state and to realize the optimization design of the dusty rain water percolation system for the traffic roads in coastal ecological sponge cities. The simulation results show that the model can realize the maximum rationalization of the utilization of the dusty rain water in the traffic road of the coastal ecological sponge cities by using the model to utilize the dusty rain water and the planning control of the traffic roads in the coastal ecological sponge cities. It can provide theoretical basis and practical application reference for decision-making department to carry out urban planning and rain water utilization.

Li, K.; Jia, L., and Shi, X., 2020. An improved algorithm for refinement of overlapping images of marine organisms. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 67–71. Coconut Creek (Florida), ISSN 0749-0208.

Aiming at the shortcomings of the current ocean Ocean image edge detection algorithm, such as poor real-time performance, slow Ocean image processing and limited storage space, an improved ocean Ocean image overlay Ocean image refinement algorithm is designed. Collect overlapping Ocean images of marine organisms and store large amounts of Ocean images in SDRAM memory; use traditional SOBEL operators to detect overlapping portions of ocean Ocean images, use non-maximum suppression to refine Ocean image edges, and clearly and accurately display ocean edges through VGA interface Ocean image. The experimental results show that the method can locate the edge of the overlapping Ocean images of marine organisms more accurately, and the refinement process has better real-time performance, which can be applied to more complex edge detection of overlapping Ocean images of marine organisms.

Lou, S.; Liu, H.Z.; Chen, M.; Liu, S.G., and Zhong, G.H., 2020. Laboratory study on solute transport affected by rigid vegetation. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 77-82. Coconut Creek (Florida), ISSN 0749-0208.

Aquatic vegetation is ubiquitous in riverine and estuary environment. With the presence of vegetation, velocity and solute transport can be greatly impacted. In this paper, laboratory experiments were carried out to analyze the influence of rigid vegetation on flow velocity and solute transport. Results have shown that the mean velocity is significantly reduced by vegetation and the maximum values of solute concentration decrease more rapidly with lower relative water depth (ratio of vegetation height to water depth). The longitudinal diffusion coefficients are found to be related with Reynolds number positively and vegetation density negatively. A modified function is proposed in this paper to effectively estimate the longitudinal diffusion coefficients, which can be used under both emergent and submerged vegetation conditions.

Sun, B.Q.; Ma, X.; Bao, X., and de Jong, M., 2020. Mapping island ecological vulnerability to urbanization: A study of twelve island counties/districts, China. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 83–87. Coconut Creek (Florida), ISSN 0749-0208.

Over the past two decades, China has witnessed an emerging research interest in island urbanization, which will set further pressure on island ecological vulnerability (IEV), especially to those islands with a fixed link to the mainland. Recently, attention has begun to focus on assessing the impact from urbanization on IEV, with several publications suggesting a dilemma between ambiguous urban planning and the emerging ecological deterioration on island areas. In this article, the IEV of China's twelve island counties/districts is assessed based on an “exposure (E) - sensitivity (S) - adaptive capacity (A)” framework and by means of an entropy method for determination of the weight of fourteen indicators. Our proposed E-S-A framework and assessment model could be rationally applied to similar coastal urban areas and islands with fixed links to the mainland internationally, which is the major contribution of our study.

Soares, M.L.G.; Castro, E.M.N.V., and Pellegrini, J.A.C., 2020. Socioenvironmental aspects related to mangrove forests under the influence of oil explotation activities in Northeastern Brazil: An interdisciplinary approach. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 88-91. Coconut Creek (Florida), ISSN 0749-0208.

This study analyses, from an interdisciplinary perspective, the connections between environmental vulnerability of the mangrove forests of Garapuá (Bahia, Brazil) and the social vulnerability of the shellfish collectors and fishermen, from the tensions inflicted with the insertion of the oil industry. It presents the interpretation of complex phenomena and integrated management of the environment, incorporating both the social and biological aspects. The analysis of local socioenvironmental processes was focused on the integration of (a) the characterization of mangrove forests structural types, by using quantitative methods, that allowed a classification of mangrove forests vulnerability to oil spill considering three components (susceptibility, sensitivity and resilience) and (b) the characterization of social tensions, through field observations and semi-structured interviews, from the point of view of the qualitative approach, that allows an analysis of the social vulnerability to changes in the community livelihoods, which are closely related to the health of the mangrove system. As a result of these analysis we found 12 Structural Types for the studied forests, comprising different levels of environmental vulnerability to oil spills. Regarding social context, some aspects related to health, education, income, transportation, religion and social organization that emerged from the interviews point to an evident fragility of the social structure. Besides this, the intense pressure for land occupation, coupled with the arrival of the oil industry, increases the vulnerability of these biological formations and, as a consequence, increases the vulnerability of the local community. The study also demonstrates that interdisciplinary analyses strengthen the debate in different segments of society (companies, environmental agencies, non-governmental organisations, universities, social groups, etc.) and, consequently, tends to foment the transformation of the socioenvironmental reality experienced by social groups without decision power.

Martinelli Filho, J.E.; Colwell, R.R.; Queioz, A.F.S.; Rivera, I.N.G., and Lopes, R.M., 2020. Vibrio cholerae O139 attached to zooplankton: Reservoir diversity and distribution over an estuarine-coastal gradient. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 92-96. Coconut Creek (Florida), ISSN 0749-0208.

Some Vibrio cholerae strains are potentially pathogenic and harmful to humans, most belong to toxigenic serogroups O1 and O139. These bacteria have many natural reservoirs and are frequently found attached to phytoplankton and zooplankton. However, the dynamics of the association between V. cholerae and zooplankton and the distribution of V. cholerae over coastal and estuarine waters and between the many biological reservoirs has proven to be of interest. Zooplankton comprise a highly diverse community and V. cholerae is known to attach mainly on crustaceans, although serogroup O1 may colonize diverse planktonic taxa including foraminiferans, polychaete larvae, and fish eggs. In order to understand the distribution of V. cholerae O139 in coastal areas and the diversity of potential zooplanktonic reservoirs, the presence of the bacterium on 43 taxa from 9 distinct phyla over an estuarine-coastal gradient in the southeast Brazilian coast was investigated during July 2005 to March 2006. Plankton was collected with a 300µm mesh net, which was washed onboard between each tow. Detection of V. cholerae O139 was assessed in whole samples and for selected taxa by DFA and DVC-DFA (Direct Fluorescence Assay and Direct Viable Count) methods. V. cholerae O139 was present in most of the estuarine samples (77%), being less common on inner shelf samples (63%) probably due to higher salinity, although a larger sampling design would be needed to test this hypothesis. Our findings suggest the occurrence of an inshore-offshore gradient for V. cholerae O139 distribution in zooplanktonic reservoir, as well as new sites for V. cholerae O139 attachment, like echinoid larvae, appendicularians, and thaliaceans. Monitoring these bacteria in cholera outbreak areas should include analyses of planktonic communities, since that may be an important natural reservoir and would ensure safety of coastal urbanized areas.

Martínez, M.L.; Silva, R.; López-Portillo, J.; Feagin, R.A., and Martínez, E. 2020. Coastal ecosystems as an ecological membrane. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 97-101. Coconut Creek (Florida), ISSN 0749-0208.

A membrane is a continuous layer that separates the interior of a cell from its surrounding cells or environment. It is selectively permeable because it regulates the transport of water, ions, and organic compounds. Its primary function is protection. Relatively analogous to a cell membrane, coastal ecosystems can be considered as an ecological membrane because they regulate the bidirectional transport of materials between the terrestrial and marine ecosystems and provide protection. The components of the ecological membrane include coral reefs, seagrass beds, beaches, coastal dunes, mangroves, marshes, and coastal lagoons. The selective permeability depends on the ecosystem. Pollutants and heavy metals, carbon, and nutrients are captured by the biota and sediments of mangroves, seagrasses, and marshes, and thus decrease the impact of pollution from the watershed to the ocean. Seagrasses, mangroves, beaches, and coastal dunes mitigate the inland effects of storms and hurricanes by reducing wave energy during storm surges. We examine how coastal ecosystems act as ecological membranes by looking at the evidence available. We focus on the flow of two features: heavy metals towards the ocean and waves towards the continent. We use field data to show how heavy metals are trapped by mangroves and coastal lagoons, which are porous ports of entry and exit. Also, wave flume experiments demonstrate how wave erosion is mitigated by vegetated coastal dunes, which act as protective barriers. Management schemes can be improved if coastal ecosystems are considered as components of a dynamic ecological membrane.

Lopes, D.M.S.; Chaves, F.O., and Tognella, M.M.P., 2020. Mangrove mortality: Analysis of natural and anthropic causes and their effects on forest dynamics. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 102-107. Coconut Creek (Florida), ISSN 0749-0208.

Located in the north coast of Espírito Santo State, Brazil, mangrove forests are associated with estuarine systems of variable flow, changing according to the climate regime of their origin. The complexity of this ecosystem is also a function of different factors, such as the physiography, the geology of the coastal plain and pollution. Natural and anthropogenic stressors can drain energy by removing structures and restricting the development, which causes variation in the number of dead individuals. In this study is reported the dynamics of the Barra Nova mangroves (in of Espírito Santo) through forest mortality investigations, either for natural or anthropic reasons. At total, eleven phytosociological data collection stations were performed along the estuary. Structural development showed an average height ranging from 3.41 to 16.69 m, average DBH of 2.69 to 21.68 cm, and trunk density of 853 to 6,360 ha^-1. Measurements of the salinity of water in the estuary ranged from 25 to 68. A large number of dead and cut trunks occurred in most stations, with the highest percentage of dead basal area (84.18 %) occurring in the station 1. Four stations harbored more than 50 % of dead basal area. Overall, the structural values were extremely variable. Although sufficiently anthropized and submitted to natural environmental changes, the results obtained here show normal and no-massive mangrove mortality, which indicate a good structural development in the analyzed areas when compared to other mangrove forests. Finally, the information about the mortality rates and processes presented in this study are helpful tools to detect pressures on ecosystems, contributing to the knowledge and protection of these natural systems.

Moulton, M.A.B.; Hesp, P.A.; Miot da Silva, G.; Keane, R., and Fernandez, G.B., 2020. Effects of the increase in vegetation cover and impact of rabbits on the geomorphology of parabolic dunes (Younghusband Peninsula - SA, Australia). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 108-112. Coconut Creek (Florida), ISSN 0749-0208.

This study examines the geomorphological changes that occurred in a large parabolic dune on the Younghusband Peninsula (YP) dune system (South Australia) due to changes in vegetation cover in the past ∼70 years. Recent studies have shown that vegetation cover has significantly increased due to the control of exotic rabbits by introducing Myxomatosis (1950's) and Rabbit Haemorrhagic Disease Virus (1990's and 2000's). Using a sequence of historical aerial photographs between 1949 and 2018 and LiDAR data (2018), changes in the geomorphological evolution of a typical parabolic dune were analyzed. In 1949 a well-developed transgressive and parabolic dunefield connected to the beach was present. In 1975 (26 years later), the parabolic dune analyzed here experienced partial stabilization by the increase in vegetation cover on the deflation basin and on top of the depositional lobe, where nebkha dunes started to develop. Vegetation of the nebkha eventually connected to the vegetation of the deflation basin, separating the parabolic dune into two. In 2018, a major stabilization of parabolic dunes, now disconnected from the beach by high foredunes, together with an increase of vegetation in the nebkha fields, deflation basin and in the interdune depression were observed. Although a gradual reduction in bare sand area within the parabolic dune and deflation basin was observed, demonstrating a clear stabilization process in the period analyzed, a significant increase in dune migration rate was observed between 1984 and 1995 (9.6 m/y), with was only acceded by the initial period 1949-1956 (14.6 m/y). These two periods correspond to times when European rabbit populations were highest in the YP, suggesting that these exotic herbivores played a significant role in the geomorphological evolution of parabolic dunes.

Muñoz-Reinoso, J.C.; Villafuerte Jordán, R; Tejada-Tejada, M., 2020. Analysis of spatio-temporal changes in the vegetation cover of the coastal landscape of Doñana. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 113-117. Coconut Creek (Florida), ISSN 0749-0208.

The analysis of changes is an important component in the understanding of the ecology of complex landscapes. The aim of this work was to study the long-term changes in the vegetation of the sands of Doñana since 1970 until present, in order to know their causes and processes. Repeated detailed photointerpretation of historical aerial images (1970, 1984, 2002, 2016) was used to map the most extended vegetation types in the Doñana sands. All the series were referenced, photointerpreted and normalized, and then processed to describe the changes produced in landcover/use. Observed vegetation changes in the protected area responded to changes in regional landscape management, as well as to local interactions in plant communities, and management. Thus, groundwater abstraction for cropping and urban supply benefited the most xerophytic plant communities, while the building of a tourist site and of a spit in the Tinto-Odiel estuary seems to be responsible for the stabilization of the mobile dunes. The expansion of Phoenicean junipers shows a successional process while the encroachment of stone pines responds to an invasion process triggered by forestry works.

Negro, V.; Del Campo, J.M.; Luengo Frades, J.; Martín Antón, M.; Esteban, M.D.; López – Gutiérrez, J.S., and Soukissian, T., In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 118–122. Coconut Creek (Florida), ISSN 0749-0208.

The evolution of the clean energies is one of the targets of the Sustainable Development Goals (SDG) of the United Nations (UN 2015 – 2030). However, the increase in the number of marine wind farms (gravity based structures < 10%; piles < 82% and jackets, tripod, tripile and floating installations 7%) with a progressive growth in depth, distance from shore, power and diameter, requires a deep reflection. The marine growth in piles and GBS structures would be studied if it is beneficial for marine ecosystems and fish species, displacement and colonization of new ones. After the installation, new substrates became colonised by a wide variety of benthic organisms. The objective of this research manuscript is to pose this challenge and the analysis in countries like Spain and the Mediterranean Countries where tourism is one of the main sources weath and the environment and landscape are essential in the preservation of the territory and the harmony with nature.

Nogueira Mendes, R.; Pereira da Silva, C.; Fonseca, C., and Gil, A., 2020. Managing and Monitoring the Recreational Use of Coastal Protected Areas: the Case of Berlengas Nature Reserve (Portugal). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 123–127. Coconut Creek (Florida), ISSN 0749-0208.

Coastal protected areas are under pressure due to recreational uses. That requires better and continuous information to ensure an effective and timely management, before irreversible impacts take place. This paper presents the methodology developed under project LIFE Berlengas, which allowed a better estimate of the annual number of visits of Berlengas Nature Reserve. Also took place the development of a barometer of visitors' perception and the construction of a spatial distribution model. Results show a high level of satisfaction with the recreational experience, despite concerns about the ‘excess of people'. The project's global outputs give a clear picture of the island's recreational use and problems and provide valuable information for the management of the nature reserve, namely for the determination of carrying capacity.

Odériz, I.; Gómez, I.; Ventura, Y.; Díaz, V.; Escalante, A.; Gómez, D.T.; Bouma, T.J., and Silva, R., 2020. Understanding drivers of connectivity and resilience in coastal ecosystems experiencing tropical cyclones. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 128–132. Coconut Creek (Florida), ISSN 0749-0208.

A better understanding of ecosystem connectivity and resilience is needed to establish efficient conservation strategies for coastal ecosystems. Physical maritime processes are key drivers for ecosystem connectivity in the Caribbean, where there is low wind and wave energy for most of the year but also short, extreme meteorological events. The energy peaks induced by tropical cyclones and the long calms are important for biodiversity. Climate change projections suggest that while there may be fewer tropical cyclones here, their intensity will increase. This paper analyses the effect of tropical cyclones on ecosystem resilience, studying both the potential connectivity and damage of mangrove, vegetated dune, seagrass and coral reef ecosystems at Puerto Morelos, Mexico. A numerical modelling approach was used to evaluate the spatial-temporal ecosystem connectivity and damage induced by hydrodynamic processes between 2005 and 2018, taking into account, wave, storm surge patterns and modifications in the vegetation cover following tropical cyclones. From our results, it was found that the balance of connectivity-damage to the intensity of the tropical cyclones depends on healthy ecosystems and the characteristics of geomorphology, with coral reef-seagrass-mangrove being more resilient to the increase in wave height but less resilient to the sea level rise. Open beaches with dune-mangrove was less resilient to the increases of both.

Paalme, T.; Torn, K.; Martin, G.; Kotta, I., and Suursaar, Ü., 2020. Littoral benthic communities under effect of heat wave and upwelling events in NE Baltic Sea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 133–137. Coconut Creek (Florida), ISSN 0749-0208.

The Baltic Sea forms a dynamic marine habitat with strong latitudinal and longitudinal gradients in many essential environmental variables. This environmental setting controls pelagic and benthic biodiversity by providing very narrow ecological niches for species displaying varying tolerances to environmental factors such as salinity, temperature and turbidity. In this study, changes in benthic communities in relation to extreme weather conditions, such as the occurrence of heat waves (HW) and coastal upwelling (CU) events, were analyzed and described in the north-eastern Baltic Sea. In the summer of 2018, the maximum water temperatures in the studied coastal sea sections varied between 20 and 25°C at 5 m depth whereby recorded values were up 7°C higher compared to that of the long-term mean. However, daily water temperature showed remarkable variation due to upwelling events occurring on multiple occasions with extreme temperature shifts of 14°C being recorded within a period of a few days. In the NE Baltic Sea, salinity gradient is up to 7 PSU in outer areas and it falls to zero in bays with riverine impact. Salinity has significant importance on benthic species abundance, richness and distribution. A rapid increase in salinity was observed during upwelling events. Extraordinarily, heat wave accompanied with upwelling event caused the increase of zoobenthic biodiversity and species-specific response of abundances. In contrast, the effect on macrovegetation species composition and proportion of opportunistic species was rather negative.

Park, Y.-G.; Kim, Y.H.; Seo, S.; Hwang J.H., and Ha, H.K., 2020. Environmental impact assessment of carbon storage using a CO₂ bubble model. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 138–142. Coconut Creek (Florida), ISSN 0749-0208.

Carbon storage in underwater geological structures is considered as a way of mitigating global climate change. One of the environmental issues related to carbon storage is the leakage of carbon dioxide from the storage. A model for tracking CO₂ bubbles in the water column has been developed to assess the environmental impact of CO₂ leakage from a shallow site that is under consideration in Korea. The dependences of the rising velocity and the solubility to bubble size are taken into account while assuming spherical bubbles of from 0.1 mm to 18 mm in diameter. Since the study area is a shallow water environment (∼170 m), leaked CO₂ bubbles reach the surface within 20 minutes during which the local horizontal currents transport the bubbles less than 500 m. While rising to the surface, less than about 2x10^-7% of leaked CO₂ is dissolved into seawater. The remaining amount is released into the air. If it is assumed that 1x10⁵ ton of CO₂ is leaked as bubbles, the pH of seawater that is influenced by the CO₂ bubbles at the absence of ocean currents would be lowered by less than 0.01 on the average. If the lateral dispersion of the bubbles by ocean currents is considered, the effect would be smaller.

Passarella, M.; Ruju, A.; De Muro, S., and Coco, G., 2020. Horizontal runup and seagrass beach cast-litters: Modelling and observations. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 143-147. Coconut Creek (Florida), ISSN 0749-0208.

We collected measurements of wave-driven swash on a beach characterized by the presence and accumulation of seagrass beach-cast litter (the so-called banquette). Beach surveys showed that this deposit can drastically steepen the foreshore thus affecting wave dynamics. This work explores the relationship between vertical and horizontal swash time series, in a previously unreported case of seagrass wrack deposits under mild to moderate incoming waves. The results from the field measurements, obtained by video imagery time stack analysis, show that the seagrass deposits influence wave runup. The horizontal runup extent can be reduced when compared with a nearby “seagrassfree” profile under the same incoming waves. The horizontal runup in case of seagrass presence seems to be approximately one-third of the seagrass absence case. The ratio between observed vertical and horizontal swash, when seagrass deposits are present, is almost 3.5 times the seagrassfree case. The SWASH model was used to extend the analysis beyond our field observations. A number of possible wave forcing scenarios were run on both the seagrass-rich and the seagrass-free profiles. Differences between the cases of seagrass presence and absence show that the horizontal wave runup in case of seagrass deposition can be largely reduced. Using observations and modelling, we show that the seagrass deposits on the beach face and berm inhibit the horizontal runup and so affect one of the key components necessary to predict coastal inundation and to manage coastal areas especially considering ongoing changes in the mean sea level.

Picado, A.; Oliveira, V.; Pereira, H.; Sousa, M.C.; Costa, L.; Almeida, A., and Dias, J.M., 2020. Assessing the potential of Minho and Lima estuaries for aquaculture. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 148-152. Coconut Creek (Florida), ISSN 0749-0208.

This work aims the identification of the best potential areas to develop aquaculture activities in Minho and Lima estuaries, especially for the species with the highest commercial value. The Analytic Hierarchy Process (AHP) methodology was applied to the results of an annual simulation with Delft3D model (including the hydrodynamic and water quality modules). After, each variable used in AHP was crossed with the environmental thresholds for development/growth of one bivalve (Portuguese Oyster) and one fish (Gilthead Seabream) species. In this way, an Exploration Index (EI) was defined in order to identify the most suitable regions according to water biophysical properties. This EI was mapped for both estuaries and results show that, in general, the low and middle estuaries present the best conditions for aquaculture development of bivalve and fish. In addition, the upper areas of both estuaries are unsuitable for aquaculture, due to the low salinity of these regions.

Pons, G.X. and del Valle, L., 2020. Bionomic cartography of the Balearic Sea: evolution of coastal marine habitats of Mallorca. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 153–157. Coconut Creek (Florida), ISSN 0749-0208.

The first compilation of marine habitats of Mallorca is presented. The Mallorcan coastline presents an environmental and biological heterogeneity, which confers great a complexity of the marine environment and treasures an important biodiversity, both at the level of species and marine communities. The main threats affecting the coastal environment are: climate change, marine pollution, over-fishing and anthropogenic occupation, resulting in dynamic changes occurring in the environment that result in the loss of certain habitats, introduction of alien species, extinction of species, degradation of the coast, etc. The objective of the present study is to compile published and unpublished information about the present state of the biodiversity of the marine biocenosis of the Balearic Sea in a spatial manner, limited to a maximum depth of two hundred meters. The purpose of this project is to provide quantitative criteria that will allow the delimitation of areas with a high level of biodiversity for conservation, and to aid planning and management of habitats and species, contributing to the reduction of biodiversity loss caused by anthropogenic impacts and global change. The project also seeks to establish the present state of marine biodiversity based on pre-existing information and the analysis of its evolution, resulting in a technological database for consultation and integrated analysis to facilitate its management, from of the change of habitat extension, representing one of the most outstanding dimensions of the science of the global change, thanks to the development of the TIG's (Geographical Information Technologies) the Anthropocene impact on the ecosystems can be traced. The final map of the Mallorca bionomic cartography has included a total of 41 habitats mapped on an area 2.978,22 km² of seabed, comprising between 0 and 50 m of the seabed surrounding the island and up to the 400 m along the Menorca canal.

Portz, L.; Manzolli, R.P.; Andrade, C.F.F.; Villate-Daza, D.A.; Bolivar D.A.B., and Alcántara-Carrió, J., 2020. Assessment of heavy metals pollution (Hg, Cr, Cd, Ni) in the sediments of Mallorquin lagoon - Barranquilla, Colombia. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 158–162. Coconut Creek (Florida), ISSN 0749-0208.

The levels of four toxic heavy metals (Hg; Cr; Cd; Ni) present in 17 sediment samples of the Mallorquin lagoon –Barranquilla (N Colombia) were investigated in order to assessing the potential risks of accumulation. The sample preparation was performed by acid microwave digestion with “Multiwave” system, carried out using GFAAS. High contamination levels, especially for Hg, Cr and Cd, were detected in samples M4 (0.199; 96.71; 1.212 µg.g^-1), M5 (0.153; 100.38; 1.076 µg.g^-1), M6 (0.140; 97.74; 1.850 µg.g^-1), M8 (0.122; 90.41; 1.023 µg.g^-1) y M9 (0.143; 100.92; 1.086 µg.g^-1). The results reflect the anthropogenic activities, as accelerated urbanization without planning, deposit for solid waste, contribution from the Magdalena River, affected by illegal mining. In addition, the Leon stream drains the entire metropolitan area by pouring into the lagoon a great amount of untreated sewage every day. The concentrations found in most samples of the Hg, Cr and Cd elements are above the internationally recommended limits. The levels of metals found are alarming, considering that this lagoon represents a source of food for the population of its surroundings.

Laporte-Fauret, Q.; Castelle, B.; Marieu, V.; Bujan, S.; Michalet, R., and Rosebery. D., 2020. Coastal dune morphology evolution combining Lidar and UAV surveys, Truc Vert beach 2011-2019. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 163–167. Coconut Creek (Florida), ISSN 0749-0208.

In the context of climate change, coastal dunes, which provide significant ecosystem services, are one of the most vulnerable coastal environments. Moreover, the lack of high resolution and large spatial scale data limits our understanding of coastal dunes, which are subject to important morphological variations over a wide range of spatial and temporal scales. This study is focused on combining non-intrusive remote sensing methods including a series of historical aerial photographs, airborne Lidar and UAV surveys in order to better understand the coastal dune morphodynamic on a wide range of spatial and temporal scales. On the time scale of decades, aerial photos indicate a reasonably stable coastal dune position, with large anthropogenic reprofiling and vegetation planting resulting in a reasonably alongshore-uniform morphology. On shorter time scales, the combination of Lidar and UAV 4-km surveys between 2011 and 2019 shows a quasi-steady dune volume increase by approximately 64 m³/m, associated with a foredune crest growth and a landward migration reaching 1.1 m and 0.54 m in average, respectively. On the other hand, the dune foot shows a more complex dynamics, dominated by a large landward migration (shoreline erosion) of approximately 20 m during the outstanding winter of 2013/2014 followed by a slow seaward migration (recovery). This study provides new insight into coastal dune morphological changes driven by both Aeolian and marine processes from the time scale of storm to approximately a decade, highlighting the relevance of UAV surveys for such applications.

Son, Y.B.; Jung, S.-K.; Cho, J. H., and Moh, T, 2020. Monitoring of the surface ocean environment under passing typhoon using a wave glider. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 168–172. Coconut Creek (Florida), ISSN 0749-0208.

A wave glider was launched in the south of Jeju, Korea and Typhoon Talim (September 9–18, 2017) passed through the East China Sea (ECS) at the same time. It is used to monitor the effect of Typhoon Talim, which had a low pressure center of 940 hPa and a maximum wind speed of 47 m/s. It made its closest approach to the typhoon around September 16–17. During this time, the atmospheric pressure dropped to 995 hPa, the wind speed was 25 m/s, and the significant wave height was 9.1 m. Satellite images showed two hot spots. One was an upwelling event in the southern part of the ECS and the other was a horizontal movement of the water column in the middle of the ECS. When the typhoon was approaching, the wave glider measured the lowest sea surface temperature and salinity, whereas the chlorophyll levels and turbidity increased, which could not be explained by local observations. However, satellite data could compare the trends before and after the typhoon's approach, where the data indicated that the vertical mixing and upwelling events near the typhoon's center were responsible for the low temperature and high chlorophyll levels in the surface layer.

Torn, K.; Peterson, A., and Herkül, K., 2020. Predicting the impact of climate change on the distribution of the key habitat-forming species in the NE Baltic Sea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 177–181. Coconut Creek (Florida), ISSN 0749-0208.

Macrophytes provide food, shelter and habitat for a multitude of other species and are therefore considered as important habitat-forming species. Loss or decrease of habitat-forming species severely affects biodiversity and functioning of coastal marine ecosystems. In the brackish Baltic Sea, such special, structuring species are large perennial macroalgae Fucus vesiculosus and Furcellaria lumbricalis on hard seabed and eelgrass Zostera marina and charophytes (Chara spp.) on soft substrates. The Baltic Sea is expected to face severe changes in environmental conditions due to climate change by the end of the 21^st century, e.g. decrease in salinity and increase in temperature, wind speed, and storminess. It is essential to forecast changes in the distribution of valuable species in order to provide data for marine environmental protection and management decisions. Boosted regression trees modelling method was used to produce current species distribution models and predict the potential changes based on future climate scenario. Data from over 10 000 benthic sampling sites were used as an input for distribution models. Following the influence of the water depth, the next major drivers of species distribution were substrate type for Fucus, temperature for the charophytes and Furcellaria, and salinity for Zostera. Based on the model predictions, the climate change may cause a significant reduction of the distributional range of Zostera and Furcellaria. Slight decline of Fucus was also detected. Unlike the other habitat-forming species, charophytes are potential winners by probably increasing their distribution in the future. However, charophytes are not able to replace the niche of the other key habitat-forming species due to different substrate, wave exposure and salinity preferences.

Zhang, W., 2020. A method for monitoring the spatial distribution of nutrients from the perspective of landscape ecology. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 182–186. Coconut Creek (Florida), ISSN 0749-0208.

In order to quantify the spatial distribution characteristics of nutrient salts and monitor the ecological landscape characteristics of the spatial distribution of nutrients, a monitoring model based on fuzzy set theory for spatial distribution of ecological landscape characteristics of nutrient salts is proposed, in which the spatial distribution of nutrient salts is used to cluster the ecological landscape. The fuzzy constraint parameter model of ecological landscape feature monitoring of spatial distribution of nutrient salts is constructed based on the constraint index set, such as beauty, landscape natural fusion and energy saving and environmental protection, and so on. The analytic hierarchy process (AHP) is used to construct the statistical analysis model of spatial distribution monitoring of nutrient salts from the perspective of landscape ecology, and the fuzzy set theory is used to design the optimal control model of the monitoring model of spatial distribution characteristics of nutrient salts. The ecological landscape feature monitoring problem of nutrient spatial distribution is transformed into the binary programming problem of seeking fuzzy set. The spatial distribution characteristic map analysis and principal component feature extraction method of nutrient salt are adopted. The spatial distribution of nutrient salts in landscape is optimized to monitor the spatial distribution characteristics of nutrient salts. The results of empirical analysis show that the monitoring of ecological landscape characteristics of spatial distribution of nutrients is more accurate, more stable and more efficient.

Zhao, R.; Lan, G.; Zhao, R.; Yao, Z., and Chen, C., 2020. The influence of regulation works on the general bifurcated estuary current. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 187-191. Coconut Creek (Florida), ISSN 0749-0208.

Under the influence of the natural environment and human activities, the estuarine current is in constant dynamic adjustment due to the joint action of the runoff current. Taking the regulation project of the Yangtze River Estuary and its South-North channel diversion as the research area, the information data of synchronous ebb tide and diversion ratio of the South-North channel diversion from 1964 to 2015 were collected, and the data were processed by using GIS and other technologies. The analysis results of the impact of the regulation project on the tidal current of the Yangtze River estuary are as follows: From September 1998 to June 2015, the ebb tide diversion ratio of the lower section of the North Channel decreased from 54.8% to 44.7%. The diversion ratio of the upper section decreased from 61.7% to 39.7%, and the diversion ratio of the upper section and the lower section showed a decreasing trend; before and after the project, the main channel of the North trough maintained the dominant nature of ebb tide, but the single width tide and dominant tide of each station had significant changes. Before the project, the percentage range of dominant tide in flood season and dry season was 56% to 78%, 52% to 61%, and after the project, the dominant tide in flood season and dry season was 56% to 78%, 52% to 61%. The percentage range is 58% to 72%, 49% to 65%.

Bayle, P.M.; Beuzen, T.; Blenkinsopp, C.E.; Baldock, T.E., and Turner, I.L., 2020. Beach profile changes under sea level rise in laboratory flume experiments at different scales. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 192–196. Coconut Creek (Florida), ISSN 0749-0208.

Laboratory wave flume experiments have been used to provide improved understanding of beach profile evolution under different wave and water level conditions. However, the understanding of the processes involved in the evolution of beach profile under Sea Level Rise (SLR) toward equilibrium is unclear. Two similar, but distorted experiments were performed at large and medium scale in order to study the qualitative morphological changes involved in beach profile evolution under SLR. Both experiments showed similar beach profile evolution. The profile change predicted by the Profile Translation Model (PTM) and the Bruun Rule underestimated the observed reatreat in both experiments. The length of the active beach profile increased under SLR. For the large scale experiment, the reflection coefficient of the beach decreased while the vertical runup increased significantly. The beachface changed faster than the outer surf zone, making the beach more dissipative.

Chen, W.; Kong, J., and Zhang, W., 2020. Simulation of erosion and deposition in sandy coasts by combining geoscience and dynamic methods. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 202-208. Coconut Creek (Florida), ISSN 0749-0208.

In order to analyze the sediment erosion and deposition caused by engineering construction in sandy coastal, combined Geoscience and dynamics model was creatively used. By introducing four distributions of the granularity parameters and grain size trend analysis (GSTA) model, the possible migration paths of bottom sand in and around the harbor engineering area were obtained. Then the net migration direction of bottom sand was obtained by using the grain-size trend vector method, and its rationality was proved by comparing with the normal wave direction in this area. Futher more, the effects of engineering on the scouring and silting of bottom sand in the surrounding sea area were simulated by dynamic numerical model based on the dominant direction wave condition. The possible silting positions were deep analyzed. It can be found that the intensity of the current was reduced by the construction of the breakwaters, and the deposition in the reclamation area can be effective controlled. The depositional intensity outside the area was obviously weakened.

Cappietti, L. and Simonetti, I., 2020. Wave-induced water-mass flow and energy transmission across shore-defense detached and emergent rubble-mound breakwaters. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 197-201. Coconut Creek (Florida), ISSN 0749-0208.

This article presents laboratory experiments and results on wave-induced water-mass flow across the detached and emergent rubble-mound breakwaters frequently proposed as coastal protection structures. A new set of laboratory experiments were conducted in order to enlarge the range of parameters already tested by the same authors. This new set of experiments confirms the previous findings, i.e. the shoreward wave-induced water-mass mean discharge that flows through the rubble-mound can be substantially higher than the water-mass mean discharge that passes behind the breakwater by overtopping its crest level.

Coelho, C.; Ferreira, M., and Marinho, B., 2020. Numerical modelling of artificial sediment nourishment impacts. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 209–213. Coconut Creek (Florida), ISSN 0749-0208.

In general, coastal erosion problems are related to significant sediments deficits. A possible coastal erosion mitigation strategy involves restoring the sediments balance through artificial nourishments. However, the complexity of the physical processes in the coastal zones challenges the numerical tools prediction capacity. This is usually overcome through numerical modelling of the shoreline evolution and the cross-shore profile along time, as an attempt to anticipate the performance of nourishments operations. The coastal morphology depends on the sediments dynamics and the incident wave climate is considered the main modelling agent responsible for the potential sediment transport capacity. The cross-shore sediment transport is usually associated to the shortterm behaviour of the morphological evolution of the beach (seasonal changes) and the longshore sediment transport is related to the long-term changes (towards an equilibrium state). Typically, these distinct sediment transport components are studied and modelled separately due to the incompatibility of their time scales of interest.

This work was developed to numerically model the impact of artificial nourishments. LTC (Long-Term Configuration, Coelho, 2005) and CS-model (Larson et al., 2016) were both applied to analyse the spatial and temporal distribution of sediments induced by artificial nourishments along and across the shore, considering different intervention scenarios. LTC was applied to evaluate the nourishments impact in the shoreline evolution and to quantify the volume of nourished sediments in different longshore locations along time. The CS-model was used to analyse the performance of multiple intervention scenarios, varying the cross-shore location, frequency and volume of the artificial nourishments. The performance of this type of intervention generally represents a smaller shoreline retreat and an increase of the cross-shore profile volumes during a limited period of time. The project results aim to increase numerical modelling capabilities, helping on the selection of optimal artificial nourishment schemes and the establishment of more efficient coastal management policies.

d'Amico, D.; Larroque, B.; Luthon, F.; Poncet, P.A., and Abadie, S., 2020. Continuous measurement and automatic processing of in-situ wave impact pressure data. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 214-219. Coconut Creek (Florida), ISSN 0749-0208.

Although wave impact has been extensively studied in laboratories, field studies are comparatively rare. However, as real wave impacts are influenced by numerous environmental factors, complementing physical studies with in-situ data is necessary to better understand the processes at stake and provide reliable tools for coastal engineers. One of the main reasons for the lack of field data is the extreme conditions usually met on site. Nowadays, technology allows to set up stations able to resist those conditions and record data over long periods. In this context, the so-called Artha breakwater, in the French Basque coast, was equipped with an in-situ laboratory to record wave impact pressures. This station enables to collect long term wave impact pressure data therefore covering any weather conditions. In the present paper, the use of computer engineering based methods to process the large amount of wave impact data is described. It involves signal pre-processing, impact automatic segmentation, automatic computation of impact parameters, and artificial intelligence to classify the impacts. Impact automatic segmentation allows to have a big database of impacts available. This database has been used to make a first classification of the strongest impacts. The classification was performed thanks to the parameters automatically computed for each impact. As preliminary results for the classification, several wave impact pressure classes have been established. The approach is encouraging since the obtained results can be compared with the existing laboratory classification. However, the results can still be improved by computing other impact parameters and considering all impacts.

Garcia, I.; Negro, V.; López, J.S.; Esteban, M.D., and Del Campo, J.M., 2020. Coastal morphological response to the effect of structures of protection against erosion. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 220–224. Coconut Creek (Florida), ISSN 0749-0208.

The prediction of sandy tombolo formation by the presence of detached breakwaters is key to the use of these elements as beach protection systems. The distance from the shoreline is a relevant factor and must be determined based on the characteristics of the incident waves, the dimensions of the artificial protections themselves, the typologies of the beach and the coastal sedimentary transport zone. In the cases analysed of detached breakwater systems with sandy tombolo formation, linear trends are obtained in between said characteristics. These results can be extrapolated to other cases located in other countries on the Mediterranean coast. Obtaining these relationships has led us to propose a new sizing method that sets the separation of the structures from the shore.

Ji, H.W.; Kim, H.J., and Park, K.Y., 2020. Lateral behavior analysis due to differential deflection between jetty structures In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1–5. Coconut Creek (Florida), ISSN 0749-0208.

Particular attention shall be paid to the design of steel/concrete structures supporting piping or equipment which have a sensitiveness to deflection. In case of excessive displacement generated in the substructure, the supported topside facilities can be subjected to additional stress caused by the imposed-deformation. Therefore differential deflection between structures should be estimated and then to be considered in the topside facilities. However, it is incredibly difficult for designer to predict the lateral behavior of the structures, using existing simple ways, under environmental and seismic load. Therefore a rigorous analysis should be performed to investigate the lateral behavior of the structures.

Jiang, Z.; Shi, L.; Guo, J., and Zhang, M., 2020. Storm response and recovery process after nourishment of Dongsha Beach, Zhujiajian Island, Zhejiang Province. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 231-236. Coconut Creek (Florida), ISSN 0749-0208.

Effective beach nourishment can reduce storm-related erosion and promote beach recovery after storms. Herein the Dongsha Beach Nourishment Project is presented as an example. Topographic survey data and sediment samples were obtained immediately before and after the landing of Typhoon Talim (tropical storm No. 1718) in 2017 and again one, two, and six months later. The digital elevation model (DEM), beach profiles, and sediment particle sizes were used to analyze the initial response of Dongsha Beach and its recovery process. The project was compared to 16 other beach nourishment projects in China to assess its effectiveness. Talim eroded the beach as a whole, although erosion was most severe in the lower headland sheltered section and the straight section. The upper headland sheltered section suffered the least erosion and recovered most during the recovery period, followed by the straight section. The lower headland sheltered section showed the least recovery. Talim coarsened grains in the straight and upper headland sheltered sections. Grains in the high tide zone in the lower headland sheltered section appeared coarsened, while grains in the middle and low tide zones were refined. Sedimentary grains in the upper headland sheltered and straight sections returned to their pre-typhoon states within the first and second months of the recovery period, respectively. The lower headland sheltered section had not recovered after six months. The fastest recovery o ccurred within the low tide zone. Recovery in the mid-tide zone followed, while the high tide zone recovered most slowly. When Dongsha Beach was compared to 16 other beaches in China, the 2017 nourishment project appeared to be inefficient. However, high stability and good natural conditions will enable better results to be achieved at Dongsha Beach with scientific planning.

Kim, D.-H. and Kim, Y.-J., 2020. Scour risk assessment of offshore wind turbine suction bucket foundation. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 237–241. Coconut Creek (Florida), ISSN 0749-0208.

Risk assessment procedure for offshore wind turbine support structures induced by scour was proposed. Probabilistic distribution of scour depth, a hazard curve, was calculated by using the C.S.U formula with parametric uncertainties. To get fragility curves of support structure, dynamic analysis was done with a certain assumed scour depth, given significant wave height and return period. Scour induced failure probability of support structure for a given wave height then can be found by integrating the multiplication of hazard and fragility. It is repeated for possible range of scour depths to form a risk curve. In numerical example, scour induced structural risk of 3MW offshore wind turbine supported by suction bucket foundation is evaluated. The proposed approach can be used in determining wind farm location where scour is significant.

Kim, I.H.; Kim, J.H.; Nam, J.M.; Chang, S.Y.; Cho, W.C.; Do, K.D.; Kim, Y.J.; Song, D.S., and Lee, H.S., 2020. Changes in sand budget for littoral cell after coastal improvement project. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 242–246. Coconut Creek (Florida), ISSN 0749-0208.

The Munam2 harbor was constructed in 1989 and the direction of Munam river mouth was changed from the Gyoam beach to the Backdo beach in order to prevent sediment deposit within the harbor inside. In order to reduce erosion damage at the Gyoam beach, the CIP started in March 2014, and three submerged breakwaters were constructed in September 2016, as well as the beach nourishment. Therefore, the characteristics of shoreline change and bathymetric change were analyzed due to wave transmission after the implementation of submerged breakwaters in littoral drift cell. The beach monitoring was performed twice annually from 2014 to 2018, that the surveying items were shoreline change, beach profile and bathymetric change, including two times wave field observation during the monitoring period. As a result, the wave transmission rate between the W-2 and W-3 shows that the function of submerged breakwater is working effectively only when a significant wave, height over 1.3 m, occurs. However, it was analyzed that there was no wave energy reduction effect as a submerged breakwater when the significant wave height is below 0.3 m. After the submerged breakwaters were constructed to solve the erosion problem, the stable coastal line was formed on the Gyoam beach.

Lee, K.-J. and Cho, Y.-S., 2020. Focusing of tsunami energy at Imwon Port. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 247–251. Coconut Creek (Florida), ISSN 0749-0208.

In the last few decades, several catastrophic tsunamis triggered by undersea earthquakes have occurred and struck not only neighboring but also distant coastal communities around the world. These tsunamis have caused a large number of human casualties and severe property damage. In this study, a geographical feature of the Imwon Port located at eastern coast of the Korean Peninsula, is investigated by studying a group of historical and virtual tsunamis caused by 3 historical and 11 virtual undersea earthquakes suggested by KEDO (1999). In addition, the effectiveness of the wave ray model is then examined by estimating tsunami heights at specific positions. Finally, the location of wave energy focusing is predicted by estimating tsunami heights and wave ray tracing, and whether the location is right is reconfirmed by the actual particle velocity vector map. The results of this study shall be used by a civil defense authority to mitigate the tsunami hazards in the case of a real tsunami attack.

Lee, H.-Y.; Jeong, Y.-H.; Kim, D.-H.; Kim, D.-S.; Cho, W.-H., and Hong, S.-J., 2020. Effects of large-scale coastal construction in shallow coastal zones of the Yellow sea on changes in storm surge height. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 252–256. Coconut Creek (Florida), ISSN 0749-0208.

Fifty-three percent of the South Korean coastline has been artificially modified due to large-scale land reclamation and dike construction. In particular, 40% of tidal flats have disappeared from the shallow coastal zones on the west coast. The construction of such large-scale coastal developments has caused the typhoon-induced maximum storm surge height to increase by 24% on average. This can primarily be ascribed to the decreased surface area of the tidal flats caused by large-scale coastal construction, given that storm surge energy is significantly dissipated over the extensive tidal flats with high depth-dependent bottom friction coefficients. Additionally, complex interactions between multiple factors, including decreased water volume and simplified coastline, caused, for example, by semi-closed bay reclamation are considered responsible for increased storm surge height.

Li, L. and Jun, K.S., 2020. The joint effect of river flow and tides on the determination of design flood levels in the Han River. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 257–261. Coconut Creek (Florida), ISSN 0749-0208.

In tidal rivers, flood water levels are driven by a joint effect of upstream river discharge and downstream tidal level. Design flood level, which is used to design structures for flood protection, is usually determined by a steady-state flow model using constant values of upstream river discharge and downstream water level as inputs. However, the approach applying a steady-state flow model can overestimate water levels in tidal rivers because flood wave attenuation and the joint effect of river flow and tides are not taken into consideration. In this study, to investigate the effect of river-tide interaction on water levels along tidal rivers, a time series of design flood flow at the upstream boundary and a large number of tide scenarios at the downstream boundary are forced into a one-dimensional hydrodynamic model of the Han River, resulting in peak water levels along the river. Design flood levels are determined through a statistical analysis of the obtained peak water levels. The design water levels estimated by the proposed approach tend to be lower than that determined by a steady-state flow model. Moreover, a significant difference in the estimated peak water levels is observed near the downstream boundary due to different tide scenarios.

Lai, L., 2020. Influence of water-rock chemical erosion on the shear strength of coastal buildings. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 262–266. Coconut Creek (Florida), ISSN 0749-0208.

This paper formulates the chemical solution preparation scheme of water-rock and the scheme of preparation and shearing of specimens, and carries out the experiment of shear strength of building under different water-rock chemical solution erosion conditions, and carries out the direct shear experiment, and analyzes the influence law of water-rock chemical action on the shear strength of building, quantificationally expresses the evolution process of the shear strength parameters of building with the chemical damage of water-rock through the introduction of chemical water-rock damage degree, and uses the method of chemical kinetics to simulate the evolution process of damage degree buildings with time in the given chemical water-rock conditions, then predicts the evolution law of shear strength parameters. The degradation of shear strength of building is analyzed and verified. Experimental results show that the degradation of shear strength of building in alkaline environments not as good as that of an acid environment, and the internal friction angle and cohesion of the building decreases with the increase of water-rock chemical damage degree.

Li Y.-Q.; You Z.-J.; Shi H.-Y., and Ren, B., 2020. Construction of in-situ coastal experimental station to continue assessing shoreline protection performance of geotextile sandbags. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 267–271. Coconut Creek (Florida), ISSN 0749-0208.

Storm-induced coastal erosion is one of main natural hazards on the coast of China and appears over one-third of the Chinese coastline. How to protect the valuable coastline from extensive erosion is of enormous economic and social values. In this study, a 74 m-long erosive coastline with high dune of about 8 m on the coast of Chudao in China has been ecologically protected with durable geotextile sandbags and then served as an in-situ permanent experimental station to continuously assess the shoreline protection performance of geotextile sandbags. The in-situ station consists of three different test segments (S1, S2, S3) and each of them was designed differently to optimize the stability and construction cost of geotextile sandbags. The sand-filled geotextile bags are designed to have the same dimensions of 1.3 m long, 0.8 m wide, and 0.2 m high and last for about 20∼30 years. Before and after the in-situ station has been built, the essential field data are collected: (1) monthly surveying of 20 permanent beach profiles to evaluate the beach profile changes; (2) monthly collection of numerous sand samples to analyze sediment grain size changes; and (3) monthly monitoring of maximum wave runup levels and sandbags stability. In analyzing the collected filed data, it is found that high wave runup is main driver for the shoreline erosion at this study site and the test segment (S2) together with geogrids is most effective and economic of the three test segments. The test segment (S2) will be redesigned to further assess the effects of sandbag size, revetment height and geogrid meshing on the performance of geotextile sandbags at this in-situ station.

López-Gutiérrez, J.S.; Esteban, M.D.; Negro, V., and Wan, Y., 2020. Evolution of extreme waves in Cadiz (SW Spain). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 272–277. Coconut Creek (Florida), ISSN 0749-0208.

The impact of climate change is one of the main concerns of the society. One of its possible consequences is the increase of extreme events: floods, droughts and storms, as reflected in the climate change documents of the 2030 Agenda. The main objective of this research is to determine whether this increase can be confirmed in the coastal area of Cádiz (Spain). To achieve that, wave measurement buoys installed in the gulf and bay have been identified and their extreme statistical distributions have been studied. The evolution of the values of the significant wave height and the peak period of wave storms has been analyzed during the last decade. For that, 20, 50, 225 and 475 years of return period have been considered. For deeper research and more conclusive data, numerical simulations of wave propagation in the zone have been performed using the CMS-Wave model, developed by the USACE Hydraulics and Coastal Laboratory. One of the main conclusions of this investigation is that an increase in the magnitude of storms on the coast of Cádiz cannot be confirmed. This statement has important effects on the design of new maritime structures and the validation of the design of maritime structures already in operation.

Martín-Antón, M.; del Campo, J.M.; Negro, V.; Luengo Frades, J.; Moreno Blasco, L.J., and Jiménez Verdejo, J.R., 2020. Land use and port-city integration in reclamation areas: A comparison between Spain and Japan. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 278–282. Coconut Creek (Florida), ISSN 0749-0208.

Land reclamation is an increasingly widespread practice, especially in Asia in recent years as a means to provide land above sea level in cities with land shortage. This is the case of Japan, especially in the populated bays of the south coast (Tokyo, Nagoya, Osaka-Kobe). After a worldwide research on this subject (Martín-Antón et al., 2016), a more specific study of the reclaimed areas in Spain and Japan, with their respective land uses, is made in this work to show the needs of growth of the port cities of each country. Two representative bays have been analyzed in detail, namely Algeciras-Gibraltar Bay in Spain and Osaka-Kobe Bay in Japan. The Algeciras Bay has a total reclaimed area of 5.6 km² whereas Osaka Bay has almost 160 km² built over the centuries. In the latter, a large percentage of the new land is currently dedicated to residential use (17%), about 28 km². Much of the housing land is next to, or even surrounded by, industrial zones, which add up to more than 60 km² (almost 40%), compared to 24% in Algeciras. In Gibraltar (Algeciras Bay), the reclaimed area with residential use is 0.5 km². It is remarkable the land areas in disuse: 8% of the total in Osaka Bay and 22% in Algeciras Bay. However, more and more land reclamation works are being built, including unfilled water areas surrounded by breakwaters (some of them to be filled with solid waste), such as the 2.6 km² in Osaka Bay. Another use is energy production, with 0.6% of the total reclaimed area in Osaka Bay dedicated to solar power plants (0.89 km²). This article aims to make a reflection on current urban needs in port areas, port-city integration and the impact on the landscape of large maritime works.

Moreno, L.; Negro, V.; Garrote, L.; Muñoz-Pérez, J.J.; López, J.S., and Esteban, M.D., 2020. An engineering method for the preliminary functional design of perched beaches: Design guidelines. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 283–288. Coconut Creek (Florida), ISSN 0749-0208.

Perched beaches are an attractive nourishment design alternative especially when either the site conditions or the characteristics of both the native and the borrow sands lead to a non-intersecting profile. The observation and suggestion of the use of this type of coastal defense scheme dates back to the 1960's, as well as the international experience in its construction. However, in spite of its use and the field and laboratory studies performed to-date, no design engineering guidance is available to support its design. The theoretical approach presented at ICS'2018 (Moreno et al., 2018) was based on dimensional analysis to identify the key dimensionless parameters with regards to the incident wave climate, the structural and geometric characteristics and location of the sill, and the beach sediment properties. Systematic mobile-bed physical model tests have been performed in a 36 × 3 × 1.5 m wave flume with five regular wave conditions. A 4-step calculation scheme is presented. The design method provides suitable (1) locations for the sill in terms of water depth, (2) sill dimensions (crest elevation and crest width), and (3) beach material characteristics of the perched beach so that successful behavior is expected.

Myrhaug, D. and Ong, M.C., 2020. Assessment of shallow water random wave-induced scour at the trunk section of breakwaters using deep water wind and wave conditions. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 289–293. Coconut Creek (Florida), ISSN 0749-0208

This article provides a simple analytical method giving estimates of random wave-induced scour at the trunk section of vertical-wall and rubble-mound breakwaters in shallow water from deep water wind and wave conditions. Results are exemplified by using a Pierson-Moskowitz model wave spectrum for deep water wind waves with the mean wind speed at the 10 m elevation above the sea surface as the parameter. The significant value of the scour depth within a sea state of random waves is provided and an example typical for field conditions is given. The method should serve as a useful tool for assessing shallow water random wave-induced scour based on input from deep water wind and wave conditions.

Ni, Y.-L.; Xie, T., and Gong, M., 2020. Analytical solution for waves propagating over local permeable seabed of constant water depth. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 294-298. Coconut Creek (Florida), ISSN 0749-0208.

The present study is concerned with the analytical solution for waves propagating over a local permeable seabed of constant water depth and wave reflection and transmission by the local permeable seabed. The fluid domain is decomposed in three subdomains of which the middle subdomain is permeable and the left and right subdomains are impermeable. Applying the linear wave theory and Darcy's law, the velocity potential of each subdomain is set up, including the effect of evanescent mode. Then, the perturbation method proposed by Mendez is used to obtain the complex wave number and the roots of evanescent mode, and the unknowns in the velocity potential are solved by the continuous conditions at the interfaces between the neighboring subdomains. Based on this analytical model, the effect of permeability coefficient, water depth and length of permeable seabed on wave propagation and transformation is discussed. The results indicate the wave height attenuates increasingly with the increase of permeability coefficient, the length of permeable seabed, and decrease of water depth. And the wave height curve oscillates around the exponential decay curve for the entire permeable seabed proposed by Dean and Dalrymple. This is the result of wave reflection and transmission induced by the local permeable seabed. The reflection coefficient is close to zero when the length of the permeable seabed is an integer multiply of a half wavelength, and it reaches the maximum value when the length of the permeable seabed is odd times of one quarter of the wavelength. The transmission coefficient reduces exponentially with the length increasing in permeable seabed.

Manzolli, R.P.; Portz, L.; Villate, D.A.; Contreras, M.D.; Padilla, L.C.J., and Alcantará-Carrió, J., 2020. Magnitude and causes of beach accretion on the eastern margin of the Tayrona National Natural Park (Colombian Caribbean), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 299–303. Coconut Creek (Florida), ISSN 0749-0208.

Beaches on the eastern margin of Tayrona National Natural Park experienced stability and even accretion over the last decade, in contrast to general erosion along the Colombian Caribbean coast. The objective of this study is to characterize shoreline change and analyze the factors contributing to the accretionary trend. Orthorectified satellite images, combined with topography from both drone images and RTK-DGPS measurements, were used to map successive shorelines from 2002-2008. Net shoreline movement and shoreline migration rates revealed these beaches had an accretionary trend, with the exception of Piscina Beach that eroded during the time period. The maintenance of natural inputs of sediment from local rivers, redistributed by littoral drift with sediment bypassing across the small headlands limiting the beaches, the resilience of the beaches to the impact of hurricanes and low human pressure allows for a positive sedimentary budget for the beaches. Piscinas Beach is the most cut off from fluvial sediment input, and despite it has a coral reef barrier, its dissipative profile indicate that it is the most exposed to wave impact.

Wu, T. and Qin, J., 2020. Influence of flow and sediment transport processes on sedimentation in groyne fields. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 304-308. Coconut Creek (Florida), ISSN 0749-0208.

Groynes have been widely used to prevent coastal erosion worldwide. Various depositional patterns have been found in groyne fields, which are affected by flow and sediment transport processes. For a groyne field dominated by a single large gyre and sediment being mainly transported in the form of suspended load, the sediment deposition pattern is consistent with the gyre structure. For groyne fields showing complex flow structures or bedload-dominant sediment transport processes, the relationship between the deposition patterns and flow and sediment transport processes remains unclear. In this study, the deposition patterns of groyne fields formed by different flow and sediment transport processes were analysed based on flume experiments. The sediment deposition patterns as well as the bedload transport process in groyne fields were accurately measured. The distribution of flow characteristics was simulated using the Horizontal Large Eddy Simulation (HLES) of the Delft3d model. The results confirmed that the deposition patterns were affected by flow structures and sediment transport processes. For suspended sediment-dominated situations, the deposition patterns were consistent with the gyre structures. For bedload-dominated conditions, sediment deposition occurred where the bed shear stress fell below the critical shear stress.

Yoo, S.-C. and Suh, S.-W., 2020. Simulation of environmental changes considering sea-level rise near a mega-scale coastal dike (Saemangeum [SMG] dike, Korea). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 309–314. Coconut Creek (Florida), ISSN 0749-0208.

The construction of one of the biggest coastal dikes in Korea, the 33-km long Saemangeum (SMG) dike, was completed in 2006. Coastal environmental changes resulted in tidal asymmetry in the near field (i.e., adjacent to the dike) and the far field (i.e., up to opposite part of the Yellow Sea). Coastal hydrodynamic variations and engineering developments for gate operations (to maintain inner reservoir water quality (WQ) standards) rapidly alter coastal environments. The sea level is expected to rise by 80 cm by the end of this century, and an additional 21.4 cm of seasonal local summer sea level jump will serve as a reversing factor of WQ. This study applied the ADCIRC and EFDC models to simulate regional and local hydrodynamic and WQ changes. The far-field impacts of the SMG will occur continuously till year 2100 along the Chinese coast with M₂ mordulation. The target water management level was set to elevation with respect to mean sea level (EL) as -1.5 m, which is very limited in terms of free discharge time for gate operation. According to the tidal excursion and residence time simulations, only 14% of gate operations in a month will be possible compared to the existing all-year-round condition, and only 4% will be exchangeable in summer. It is found that SMG yields alteration of tidal hydrodynamics showing overall de-amplification of ∼10 cm in the Yellow Sea (YS), especially along the west coast of Korea (WCK), as well as a slight amplification of ∼10 cm on the eastern coast of China. In addition, reducing the time for inner discharge because of the rising outer sea level directly influences WQ both in the areas near the gates and the inner water due to the increased residence time. Intensive study including long-term variations in tidal asymmetry and associated morphologies is needed to manage the hydrodynamic and/or WQ changes associated with such mega-scale coastal constructions.

Chen, X.D.; Yu, S.B.; Chen, J.; Zhang, C.K.; Dai, W.Q., and Zhang, Q., 2020. Environmental impact of large-scale tidal flats reclamation in Jiangsu, China. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 315–319. Coconut Creek (Florida), ISSN 0749-0208.

While coastal reclamation creates huge benefits by providing a variety of resources for socio-economic development, the environmental impact of human activities should be appropriately evaluated. Since 2009, a large-scale tidal flats reclamation project was conducted. The project was suspended and no more reclamation was conducted after 2017. An integral assessment method has been desperately in need to comprehensively understand the environmental impact of such project which has been partly completed. A comparison was made between the states before and after the implementation of the reclamation project in Jiangsu coast. Results show that generally the large-scale reclamation had limited influence on the tidal system and coastal evolution, but inevitably changed the local hydrodynamic conditions in the vicinity of most project sites. Ecology resource suffered most pressure. Environmental pollution was also a critical indicator. An integrated framework was proposed based on the conceptual model of “Driver-Pressure-State-Impact-Response” to assess the environment impact of large-scale reclamation in Jiangsu tidal flats. However, large numbers of relevant data need to be collected on the way forward. Nevertheless, this assessment model will promote the long-term harmonious development of economic development and ecosystem health.

Zhang, M.; Li, Z.; Liu, Q.; Zhao, Z., and Liu, S., 2020. Forward modeling of fine seismic wave velocity model in coastal oilfields. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 320-324. Coconut Creek (Florida), ISSN 0749-0208.

In order to accurately calculate the fine seismic wave velocity of the coastal oil field, the forward characteristic evolution model of the fine seismic wave velocity model can be effectively evaluated. Because the structure of coastal oil field is complex and the environment is bad, it is very important to study the parameters of fine seismic wave velocity, but there is no effective and reasonable method. A forward modeling method for fine seismic wave velocity model of coastal oil field based on equivalent seepage resistance method is proposed. The fine seismic wave velocity of coastal oil field and the fine seismic wave velocity of oil field regional evolution time are derived by using non-piston water flooding. By using the method of equivalent seepage resistance and taking non-piston water flooding as the research carrier, the seepage zone in the distribution area of fine seismic wave in coastal oil field is divided into three seismic wave impact evolution zones. The forward velocity formula and the inversion formula of fine seismic wave velocity are deduced reasonably. In the simulation experiment, the five-point area pattern of multi-branch horizontal wells is simulated and analyzed from two aspects: the penetration of seismic waves and the number of branches. The simulation results show that the penetration and branch number of seismic waves are linearly correlated, and the number of branches increases with the increase of the penetration of seismic waves. The numerical simulation results show a good low error performance. The forward modeling of seismic wave can improve the calculation precision of fine seismic wave velocity in production well pattern. It has great practical significance to improve the accuracy of reservoir and oil production engineering.

Zhu, R.-H.; Zheng, J.-H; Zhang, J.-B.; Wang, H.-K.; Li, T.-F., and Liu, R.-L, 2020. Application of the sonar detection technique to inspection of vertical quay wall. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 325-329. Coconut Creek (Florida), ISSN 0749-0208.

The sonar detection technique can play an important role in underwater inspections to the port and coastal engineering, and such inspections may prevent or mitigate disasters from the coast engineering. This technique has been widely used in underwater surveys, but little research has been done on the inspection ability for vertical quay walls. The sonar detection of vertical quay wall has its own characteristics, and the theoretical resolution can be calculated from the formula. However, affected by the working conditions and environment, the inspection ability is not the same as the theoretical result. This study introduced and performed underwater field model experiment to study the actual inspection ability of the vertical quay wall with a homemade vertical structure concrete model, and conducted the experiment in harbor water at different working distances. The 3D scanning sonar with 1 degree transmitting beam angle was tested to be valid to gather data at the proper working distance to study the detailed inspection of vertical targets with sizes no less than 5 cm, and the sonar is able to distinguish long strip-shape targets as a whole with width no less than 1cm at working distance of no more than 1.5m. Results of the field inspection for the caisson joints of a gravity wharf by different sonars were compared with each other and verified by underwater video shootings. The 3D scanning sonar was verified to be valid in the caisson joint inspection, and MBES was tested to be fast in working efficiency but with errors caused by long working distance, which was restricted by the sea conditions.

Aleksyutina, D.; Ogorodov, S., and Shilova O.S., 2020. Simulation of coastal dynamics at the Kara Sea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 330–335. Coconut Creek (Florida), ISSN 0749-0208.

The coastal zone of the Arctic seas is characterized by high dynamics due to the presence of permafrost. In SW part of the Kara Sea the coastal cliffs are composed of frozen unlitified deposits. Massive ice beds and ice wedges are widespread on various absolute heights. In this region, the coastal erosion rates are 0.5 to 2 m·a^-1. At the points where high cliffs have massive ice beds inclusions and low cliffs experience great storm events, erosion rates may rich 7-14 m·a^-1. The coastal retreat rates have a lognormal distribution. In order to understand the destruction processes on the key sites, numeric simulations were performed. The model is based on the heat balance equation and the Stefan approach. Boundary conditions were set based on climatic parameters obtained according to the weather station (Marre-Sale). According to this data, two different periods can be identified: with a higher thermal action in 1995-2017, and a lower in 1973-1995. For these periods, numerical simulation of the coastal retreat was made. The physical parameters of the sediments applied for the simulations were derived from laboratory tests and literature The lithological composition varies from loamy clays and silts to gravel sands. Since thermodenudation causing erosion rate strongly depends on slope deposits removal process, different regimes of removal of the thawed layer were simulated. The crucial influence of slope cleaning mode, ice content in the soils and their reaction under climate changes on the erosion rates were demonstrated. Observed and simulated results correlate well.

Montreuil, A-L.; Chen, M.; Brand, E.; De Wulf, A.; De Sloover, L.; Dan, S., and Verwaest, T., 2020. Early-stage aeolain dune development and dynamics on the upper-beach. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 336–340. Coconut Creek (Florida), ISSN 0749-0208.

Early-stage aeolian protodunes, or ephemeral dunes, are ubiquitous features on the upper-beach, acting as requisite precursors to fully developed dunes. Their formation during high energy aeolian sand transport events plays an important role in the beach morphodynamics and sediment budget. However, little is documented about their life cycle from generation to degeneration as well as their interactions with environmental factors. This study takes the opportunity of the advance in high resolution terrestrial laser scanning technique to acquire morphological changes at an appropriate frequency and spatial resolution to characterize ephemeral dune dynamics. A 1.5 days set of hourly laser scans indicates the development of a field of protodunes with a height ranging from 0.15 to 0.42 m concentrated on the upper-beach. They develop in a few hours under oblique alongshore winds above 7 m/s. The results also show that the protodunes migrate relatively fast with an average rate up to 1.1 cm/hour. Spatial and temporal variability of their morphological characteristics occur across the upper-beach. The morphological changes reflect the pattern of the development and behaviour of the protodune field which seem to be self-organized within a complex system controlled by the interactions between the bedforms themselves, environmental factors and aeolian sediment transport. Our findings highlight the importance of quantifying processes at spatio-temporal scales for monitoring protodune morphology.

Aranda, M.; Gracia, F.J.; Peralta, G., and Flor-Blanco, G., 2020. The application of high-resolution mapping for the analysis of recent eco-geomorphological changes in San Vicente de la Barquera estuary (North Spain). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 341–345. Coconut Creek (Florida), ISSN 0749-0208.

Geomorphological changes in recent decades in the estuarine system of San Vicente de la Barquera (Cantabria, Spain) are analyzed. For this analysis, two high-resolution geomorphological maps are generated from visual interpretation of digital orthophotos (1956 and 2017). The Habitat Digitizer Tool for ArcGIS was used as an interface to rapidly identify and assign attributes to the polygons created. Settings are conditioned at a spatial scale of 1:2500 with a minimum mapping unit (MMU) of 50 m². The main results show remarkable changes in the studied saltmarshes, with a drastic 85% reduction in the occupied surface (from 25.65% of the estuary in 1956, to 3.62% in 2017). The results here presented suggest that the geomorphological changes and recent evolution observed in the saltmarshes of San Vicente de la Barquera may be related to: (1) a decrease on river sedimentary discharge and a higher coastal sediment transport inside the estuary, (2) human interventions like dredging of the main channel or shore urbanization and, finally, (3) changes on mean sea level rise in the last century, which significantly affect low-lying areas which have not potential area to migrate. These factors have altered the estuarine dynamics, reducing the area occupied by some geomorphological units and, therefore, causing habitat changes and disappearance. This work illustrates the importance of fine-resolution mapping to estimate trends and the development of proper management measures in order to restore estuarine habitats and their associated ecosystem services.

Shariful, F.; Sedrati, M.; Ariffin, E.H.; Md Shubri, S., and Akhir, M.F., 2020. Impact of 2019 tropical storm (Pabuk) on beach morphology, Terengganu coast (Malaysia). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 346-350. Coconut Creek (Florida), ISSN 0749-0208.

Occurrences of tropical storms, including cyclone and typhoon, across the Southeast Asia region are uncommon despite being highly prone to monsoon storm. Nevertheless, Thailand was recently hit by a cyclone called Pabuk, which had affected several parts of Malaysia with a significant impact along the Terengganu coastal area, particularly its infrastructure erected along the coastal line. This Pabuk storm was associated with the direction of waves, along with intense current velocities and strong winds, in comparison to a normal monsoon storm. The Pabuk storm had struck the Terengganu coastal area precisely in January 2019, which was during the Northeast monsoon storm that commonly occurs between November and January with heavy rainfall and strong wind. Interestingly, in November and December 2018, the rainfall was minimal to only a few drops, while the weather was hot and dry. In order to comprehend the variances between seasonal monsoon and the Pabuk storm, beach profile surveys were conducted during monsoon seasons, including the Southwest monsoon (June 2018), the transition monsoon (October 2018), the Northeast monsoon (December 2018), and after the Pabuk storm. In particular, during the Northeast monsoon season, erosion was absent along the beach, except for some discovery in the anthropogenic area, while the beach volume decreased from the beach dune and foreshore areas after the Pabuk storm. This study revealed that the highest significant wave height from numerical model (MIKE-21) during the Pabuk storm inflicted a significant morphological change onto the beach dune. Since the recovery of beach dune varies depending on the availability of sediment source, the recovery process may take a longer period in the anthropogenic areas. Such findings are integral for coastal managers involved in repairing and rebuilding activities on the adversely affected coastal infrastructures along the coastal line at the event of tropical storm.

Balouin, Y.; Bourrin, F.; Meslard, F.; Palvadeau, E., and Robin, N., 2020. Assessing the role of storm waves and river discharge on sediment bypassing mechanisms at the Têt river mouth in the Mediterranean (southeast France). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 351–355. Coconut Creek (Florida), ISSN 0749-0208.

River mouths along sandy coastlines are influenced by alongshore transport of littoral sands and the interaction of hydrodynamics processes at the river mouth. These interaction are responsible for opening/closure of river outlets and subsequent episodes of sand bypassing by spitbreaching. Here, we study these mechanisms of alongshore sediment bypassing at a river mouth along the French Mediterranean coast. Over the last 6 years, bypassing processes were found to be associated with spit elongation and spit breaching. Hydrodynamics measurements were implemented in order to assess the respective role of river jet and wave conditions on these opening/breaching episodes. Results tends to point on one major mechanism: spit overtoping that induces breaching. For the floods events analysed, the river jet has apparently only a very low contribution to this opening.

Baranskaya, A.V.; Novikova, A.V.; Shabanova, N.; Romanenko, F., and Ogorodov, S., 2020. Late Quaternary and modern evolution of permafrost coasts at Beliy Island, Kara Sea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 356–361. Coconut Creek (Florida), ISSN 0749-0208.

The low coasts of Beliy Island, Kara Sea, composed of perennially frozen sands and silts with peat are extremely vulnerable to all changes in sea level and climate conditions in the Arctic. The complex Holocene history of the island is reflected in sediments outcropping in its coastal bluffs. Modern erosion leads to destruction of these bluffs, continuing to change the topography of the island.

To reconstruct Late Quaternary history, coastal exposures were investigated. They generally consist of three units: the lower clays and sands with plant debris, parallel and rippled lamination formed in shallow marine conditions in MIS 3. The middle sandy unit with allochtonuous peat lenses was deposited in the mid-Holocene (5 to 8 ka BP) in coastal conditions. The upper peats, sandy loams and silts accumulated in continental conditions after 5 ka.

To estimate modern coastal erosion rates, multitemporal satellite imagery (1969-2016) was used. The western coast retreated at higher average rates than the eastern coast (1.9±0.2 m/y and 1.2±0.2 m/y, respectively). Extreme rates during 47 years were higher from the eastern side (4.6 m/y compared to 3.1 m/y in the west). Both mean and extreme erosion rates are higher than the known erosion intensity of the Kara Sea coastal dynamics monitoring sites, evidencing considerable vulnerability of the low coasts to erosion in the changing climate. Evolution of the hydrometeorological parameters affecting coastal erosion in the XX-XXI century was estimated. High average retreat rates must have happened in the 2000s-2010s as a result of both temperature and wave energy increase providing unprecedent environmental forcing of coastal dynamics.

Barbosa, N.; Taquez, D.; Santos Jr, O.; Freitas Neto, O.D., and Scudelari, A., 2020. The effect of basal erosion on sea cliff stability. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 362–366. Coconut Creek (Florida), ISSN 0749-0208.

Coastal areas attract substantial interest from the general population, and development is quite common in these regions. Therefore, it is necessary to study coastal erosive processes to provide a better understanding of the factors that influence the stability of sea cliffs and consequently their safety. In this paper, two typical cliff profiles were studied: a vertical cliff section and another with a lower slope. Both profiles are representative of slopes existing on the northeastern coast of Brazil. Basal incisions of 1 m, 2 m and 3 m were evaluated. The cliffs considered are not subjected to anthropogenic activities, and thus, only natural conditions influence their stability. The stability of the cliffs was investigated through a comparative analysis between the tensile stresses acting on the slopes and the tensile strengths of the materials considered. For the cliff with a lower slope, it was verified that the tensile stresses obtained presented low values, whereas in the vertical cliff, the tensile stresses were significantly higher. The main mechanism responsible for triggering instability processes is the partial increase in the degree of soil saturation caused by rainfall, which decreases the soil strength and triggers landslides. From the tests carried out, it was observed that the cohesion intercept of the saturated soils is approximately 26% of the value obtained for the soils with natural moisture content. However, the angles of internal friction in both cases suffer negligible variations. The study of the stability analysis presented in this paper effectively represents the types of failures observed in cliffs on the Brazilian coast. The analysis by tensile stress is much more coherent than the failure surfaces obtained by traditional methods of analysis.

Belova, N.G.; Novikova, A.V.; Günther, F., and Shabanova, N.N., 2020. Spatiotemporal variability of coastal retreat rates at Western Yamal Peninsula, Russia, based on remotely sensed data. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 367–371. Coconut Creek (Florida), ISSN 0749-0208.

The work aims at estimating coastal retreat at Western Yamal from 1972 to 2016, when significant climate change occurred in the Arctic. One fourth of the Kara Sea coasts are collapsing cliffs composed of permafrost, i.e. thermoabrasional coasts. Although these coasts are bounded by sea ice for most of the year, they retreat with rates comparable to those of temperate latitudes, but only during the short ice-free period. Permafrost cliffs are not only eroded by waves; they also get destroyed by melting of the ground ice bounding the sediments (thermo-denudation). Arctic coasts are sensitive to climate change, as rising summer air temperatures lead to deeper thawing of frozen sediments, and longer ice-free periods extend the time of the wave impact on the coast. At Western Yamal, in the area of Kharasavey gas condensate field, the average long-term coastal retreat rate is 1.3 m/yr (1972-2016) for 5.9 km of the coastline, reaching mean annual rates of 3 m/yr in some areas. The greatest retreat rates are typical for coastal segments composed of permafrost with high ice content. Based on the analysis of multitemporal aerial and space images, the coastal retreat rates for four time periods between 1972 and 2016 were estimated. The retreat rates were brought into context with data on sediment composition and type (grain size, ice content, presence of massive ice), reconstructed evolution of hydrometeorological parameters and the history of economic development of Kharasavey area. Unlike other Kara Sea sites of coastal dynamics' monitoring, the strongest coastal retreat rates at Kharasavey were observed earlier in 1977-1988, when the hydrometeorological stress was low, implying vulnerability of the coasts to significant anthropogenic impact at the beginning of the gas field development.

Bergsma, E.W.J.; Sadio, M.; Sakho, I.; Almar, R.; Garlan, T.; Gosselin, M., and Gauduin, H., 2020. Sand-spit evolution and inlet dynamics derived from space-borne optical imagery: Is the Senegal-river inlet closing? In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 372-376. Coconut Creek (Florida), ISSN 0749-0208.

With the majority of the world' population living in urbanised coastal zones, regional-scale coastal monitoring is a paramount tool to assess the risk exposure of local areas. At St. Louis, Senegal the coast experienced a recent acceleration in coastal erosion. Additionally, the sand-spit South of St. Louis is highly dynamic with one of the largest migration rates worldwide. In this study we showcase the use of satellite imagery to assess the morphological change of the St. Louis inlet position over more than 3 decades. The Senegal river inlet was artificially opened in 2003 Northward of its natural position. The effect of this opening is measured through local shoreline erosion and use of satellite data to predict the next closure of the Senegal-river inlet. Since the artificial breach coastal erosion at the fishmarket of St. Louis was measured, while the sand-spit initially accreted. Southerly sand-spit migration rates that varied from 475 m per year (before an artificial breach in 2003) to 590 m per year after the breach. With these migration rates and assuming limited changes in, for example, river run-off and wave environment, the inlet will close again around 2050 and 2055.

Biausque, M. and Senechal, N., 2020. Analysis of two contrasting seasonal recovery periods of an open sandy beach, using high frequency DGPS surveys. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 377-381. Coconut Creek (Florida), ISSN 0749-0208.

High frequency DGPS surveys were undertaken for 2.5 years (November 2015 until April 2018) on an open sandy double barred beach in the SW of France (Biscarrosse Beach) covering three winter and two summer periods. On those latitudes, summers are usually described as seasonal recovery periods. The morphological response of the beach during two consecutive summer periods (2016 and 2017) has been analyzed to identify processes involved in seasonal recovery. Analysis of alongshore mean profiles indicates that the summer 2016 is marked by a progressive berm reconstruction, manly driven by cross-shore sediment transport. The beach recovery in 2016 can be characterized as complete with a stable berm through the summer season associated with steady beach cusps, and a seaward dune foot migration. During this summer the variations in volume of each section of the beach (intertidal/supratidal beach and dune) show sediment transport firstly orientated from the intertidal beach toward the supratidal one, and, later, driven from the supratidal beach to the dune. This cycle is coherent with recent observations described by Philips (2017). In contrast, the summer 2017 is characterized by an incomplete recovery, an unstable berm and so, a much more complex dynamic: the berm, rapidly rebuild (by the end of June), started to erode in July. Six sequences of cross-shore sediment exchanges are measurable along the season between the intertidal and the supratidal beach, inducing successive erosion/ accretion of both sections of the beach. Thus, according to those results summers 2016 and 2017 present variable spatial and temporal dynamics. Moreover, analysis of hydrodynamic and environmental factors indicate that recovery periods not only depend on hydrodynamic conditions, such as wave energy and tide, but also on winter/summer morphological coupling, and sandbar/beach coupling.

Billson, O.J.; Russell, P.; Davidson, M.; Poate, T.; Amoudry, L.O., and Williams, M.E., 2020. In-situ observations of infragravity response during extreme storms on sand and gravel beaches. Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 382–386. Coconut Creek (Florida), ISSN 0749-0208.

Infragravity waves (frequency = 0.005 – 0.05 Hz) play a key role in coastal storm impacts such as flooding and beach/dune erosion. They are known to dominate the inner surf zone on low-sloping sandy beaches during storms. However, in large wave conditions, their importance on different beach types, of variable swell and wind-waves dominance, is largely unknown. Here, a new dataset is presented comprising in-situ observations during storm wave conditions (significant wave height of 3.3 m, peak periods of 18 s and return periods up to 1 in 60 years) from two contrasting sites: a low-sloping sandy beach and a steep gravel beach. Wave measurements were collected seaward of the breakpoint by wave buoys and bed-mounted acoustic Doppler current profilers, and through the surf zone using arrays of pressure transducers. Wave spectra showed contrasting evolution from the shoaling zone to the inner surf zone at the two sites. At the sandy beach, gravity band energy dissipated gradually as depth reduced, while infragravity band energy simultaneously increased, resulting in strongly infragravity-dominated wave spectra in the inner surf zone. At the steep gravel site, a rapid drop in short wave energy was observed, with limited growth of infragravity energy so that inner surf zone spectra showed a low energy peak in the infragravity band. The normalized bed slope parameter indicated whether infragravity waves were generated by bound long wave release or breakpoint forcing, showing that the former (latter) was dominant on the sandy (gravel) beach. In spite of these differences, the shoreline wave spectra under storm wave conditions were infragravity-dominated on both the sandy and gravel beaches.

Billy, J.; Baudouin, V.; Portal, A.; Deparis, J.; Bitri, A., and Garcin, M., 2020. An innovative approach for a comprehensive characterization of coastal dune systems through internal architecture and the associated intrinsic geophysical properties. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 387–391. Coconut Creek (Florida), ISSN 0749-0208.

Comprehensive geophysical sub-surface investigations of coastal systems provide a better understanding of the organization of sediment deposits and the behavior of coastal areas. An innovative high yield multi-geophysical approach has been developed to investigate internal properties of coastal dunes and their associated environments, combining continuous, multiscale and non-destructive methods: (i) terrestrial seismic surveys MASW, (ii) electrical resistivity tomography and (iii) ground-penetrating radar. This approach was deployed to characterize a complex sandy dune system at the Pays-De-Monts (Atlantic Coast, France), a 27-km-long and 0.6-2-km wide coastal system composed of three generations of dunes (4 to 25 m high) separated by former marshes or large slack areas. This paper focuses on the most seaward dunes (over a width of 600 m with 5-6 m high dunes) at La Parée Grollier, in the northern part of the Pays-De-Monts. It shows a cross-interpretation analysis of the multiple geophysical results, along a same profile, and highlights the power of such approach to characterize coastal dune system by an innovative way. Data allowed the differentiation of (i) three seismic layers (SU_1-3), (ii) eight electrical resistivity bodies (EU_1-8), and (iii) six GPR units (RU_1-6), characterizing subsurface deposits at large scale, medium scale and with details, respectively. Data interpretation of the combine methods highlights: (1) the entire sediment cover up to the substratum; (2) the detail internal architecture and connection between the different components of the dune system; and (3) consistent correlation between the georadar and geo-electrical results through the sandy dune. Such knowledge of intrinsic parameters of coastal systems is essential to advance geo-mechanical interpretations, to 3D-modelize coastal zone and to predict realistic scenarios of longshore and cross-shore coastal systems evolution, and to enhance coastal zone management.

Brayne, R.P.; Lorang, M.S.; Naylor, L.A., and Reinhardt, L., 2020. Field-based observation of the entrainment threshold of cobbles with motion loggers. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 392–397. Coconut Creek (Florida), ISSN 0749-0208.

Beaches composed of pebble to boulder-sized material are a common feature of coastal regions and provide effective protection against wave attack. The wave-related entrainment threshold of these coarse particles is of utmost importance to defining the onset of dynamic beach behavior. Wave-competence equations derived to predict the boundary between particle stability and entrainment when acted on by waves (e.g. Lorang, 2000) are useful when designing artificial gravel beaches as shore protection structures because they help inform the size of material required to mimic the dynamic behavior of their natural counterpart. The objective of this study is to use motion loggers embedded within native cobbles to measure the entrainment threshold during storm wave events to provide much-needed field data with which to test the accuracy of the Lorang (2000) equations. The movement of 14 cobbles were observed over a range of conditions (0.10 m < H_S < 0.52 m) during five separate 1.5-hour-long experiments on coarse pebble/cobble beach at Flathead Lake, Montana, USA. The entrainment threshold was positively related to wave power and was accurately predicted by the Lorang (2000) equations using significant wave height, mean period and beach slope to estimate swash velocities and run-up height as driving variables. More experiments are required to constrain the value(s) used for the beach stability coefficient K_r, although the values found here correspond with the widely used Hudson Formula (Hudson, 1952). Alternatively, directly quantifying swash velocities and run-up elevations from video analysis would greatly improve the results rather than estimating these primary variables. These results provide a unique insight into the wave-competence approach to designing dynamic revetments and artificial gravel beaches as shore protection alternatives to rip-rap and seawalls at a time when rising sea level and a potential increase in storm intensity are likely to increase the wave impact on coastal regions.

Bugajny, N. and Furmańczyk, K., 2020. Short-term volumetric changes of berm and beachface during storm calming. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 398–402. Coconut Creek (Florida), ISSN 0749-0208.

The storm calming coastal processes are presented in the paper. Within these hydrodynamic conditions, the most intensive changes take place on the berm, the beachface and the nearshore, where erosion and accumulation processes are observed. This research was carried out along an approx. 300 m long section of the dune coast of the southern Baltic Sea, in the area of Dziwnow Spit. The measurements were taken using GPS RTK within four days, twice a day. Consecutive profiles were located in about 20 m distance from each other covering the most dynamic part of the beach and the shallow bottom to a depth of about 0.5 m. In order to compare volumetric changes in the profiles, a 1 m grid along every profile was created. Next, a rate of those changes was calculated for each grid. During the storm calming, the significant wave height changed from 1.0 m to 0.2 m from SW to SE direction, and the water level dropped down by 20 cm. A diversified rate of volumetric changes of the beach in time and space was identified, depending on profile location along the coast. Also, temporal and spatial differentiation of the beach volumetric change rate was found, depending on profile location and its parts. The beach accumulation rate did not exceed 0.012 m³/m/h, and erosion - 0.019 m³/m/h, while in the shallow bottom, the accumulation rate did not exceed 0.030 m³/m/h, and erosion rate - 0.020 m³/m/h. The diversity of these processes in time and space are observed and they are related to hydrodynamic conditions. The obtained results will help to understand the accumulation processes during the storm calming in non-tidal environments.

Pereira, L.C.C.; Trindade, W.; Nascimento, A.T.; Vila Concejo, A., and Jimenez, J.A., 2020. Morphodynamic studies in sandy Amazonian environments. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 403–407. Coconut Creek (Florida), ISSN 0749-0208.

The present study evaluated the different morphodynamic scenarios that arise under varying tidal and wave conditions on a sandy beach (Ajuruteua) and an exposed tidal flat (Vila dos Pescadores) on the Amazon coast of northern Brazil. For this, four field campaigns were conducted, covering a full annual cycle, for the collection of nearshore data (tides, waves, rainfall, topographic changes, and sediment characteristics). These data were complemented with meteorological (rainfall), fluvial discharge and offshore (wave and wind) data obtained from the stations of official agencies. Ajuruteua beach has very fine sand (2.1-2.7 φ) with a typical profile characterized by a narrow high-tide zone (<10 m) and intertidal zone with a low-gradient (1°–2°) and varying width, ranging from 250 m (neap tide) to 350 m (spring tide). At that beach, tidal flat conditions occur primarily during the equinoctial period, when tidal asymmetry is strongest (ebb tide longer than 7 h). At Vila dos Pescadores, the sand is also fine (more than 70% of grain 2.0-3.0 φ) and the migration of the main tidal channel is delimited by a low, broad terrace. In this area, the transition between tide-dominated, tide-modified, and wave-dominated conditions occurs during the high tide, primarily during the dry season, when the highest H_s values (up to 1.3 m) are recorded on the tidal flat. In the study region, the unregulated construction of buildings has resulted in increasing impacts from erosive processes, which has partially or totally destroyed the existing beachfront infrastructure. The results of the present study provide important insights for the development of more effective management strategies for the local environments.

Ferreira, C.C.; Abreu, T.; Silva, P.A.; Bernabeu, A.; Romão, S., and Staudt, F., 2020. Sediment transport with mixed sand in nonlinear regular waves. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 408–411. Coconut Creek (Florida), ISSN 0749-0208.

This work presents the results of an experiment carried out in the Large Wave Flume (Großer Wellenkanal, GWK) in Hannover, which enables full-scale wave experiments to be conducted above sand beds. The experiment consisted of a set of regular waves propagating over a 30 m long horizontal bed composed of a bimodal mixture of fine (F) and coarse (C) sands. Wave gauges placed along the test section and an ADV (Acoustic Doppler Velocimeter) placed above the wave bottom boundary layer allow characterizing the wave nonlinearity parameters (skewness and asymmetry). Fluorescent sand was inserted at the beginning of each experiment and subsequent bed samples allowed tracking its movement, differentiating between the coarse and fine sand fractions.

This study presents the results obtained with a particular sediment mixture (75%F+25%C) for two regular trochoidal wave conditions with the same wave period, 7 s, but different wave heights, 1.0 and 1.5 m. The total net transport rates estimated from a practical sediment transport formula, which includes both effects of wave asymmetry and skewness, are comparable with those obtained with the fluorescent tracer.

Chen, L.; Zhou, Z.; Xu, F.; Möller, I., and Zhang, C.K., 2020. Field observation of saltmarsh-edge morphology and associated vegetation characteristics in an open-coast tidal flat. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 412–416. Coconut Creek (Florida), ISSN 0749-0208.

Saltmarshes are vulnerable morphological units, while their edges serve as an important indicator for regional sediment budget. The relation between three forms of saltmarsh edges and the vegetation characteristics was explored. Saltmarsh quadrats as well as their associated hydrodynamics were analyzed on the tidal flat of the Yancheng Nature Reserve in the middle Jiangsu coast, China. Results indicate that different marsh-edge morphologies were associated with different vegetation parameters, i.e., density, mean diameter, and dry biomass. These parameters showed different spatial variational trends and certain phase differences existed between these trends. However, the mean plant height presented a comparable spatial variational trend in different marsh-edge forms, indicating that the plant height was likely controlled by tidal range which was nearly the same in different sites. A transitional zone was defined between the smooth section and the cliff section, where the young seeding marsh showed a cyclic growth-erosion-regrowth behavior. Therefore, the hydrodynamic condition in this transitional area may be considered as a probe of the critical state between the cliff form and the smooth form.

Cho, J.H.; Son, Y.B.; Shin D.-H.; Moh, T.J.; Jang S.; Lee S.Y.; Lim D.G., and Kum B.C., 2020. Changes in underwater visibility due to turbidity associated with Typhoon Soulik. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 417-421. Coconut Creek (Florida), ISSN 0749-0208.

Changes of visibility in the water column off the southern coast of Korea due to the effects of Typhoon Soulik (Aug. 22–23, 2018; 955 hPa; maximum wind speed, 40 m/s) were investigated. The beam attenuation coefficient (BAC) was measured using a transmissometer (C-Star; Wet Labs, Inc.), and visibility range was calculated using the conversion method employed by the US Navy. For comparison and verification of the data, a conductivity–depth–temperature (CTD) probe (SBE19 Plus; Sea-Bird Scientific) equipped with optical backscatter and fluorescence sensors was deployed simultaneously with the transmissometer. The Secchi depth was also estimated during each cast to improve accuracy. The Secchi depth deviated by up to 20% from the calculated visibility range. Additionally, during continuous observation of BAC from the seafloor upward, a light source (color temperature: 6,500 K) was installed on a 5-m bar with length markings, and a video camera recorded changes in visibility. Daily Geostationary Ocean Color Imager (GOCI) satellite data were used to identify changes in surface visibility in the study area. Before the typhoon, the visibility in the water column was in the range 25–30 m. Near the seafloor, visibility approached 0 m due to a 3–6-m turbidity current. The visibility distance was significantly shorter in the bottom layers based on video images. Four days after Typhoon Soulik had passed over the Korean Peninsula, the visibility was in the range 2.6–9.0 m in the upper layers of the water column, increasing gradually to 11 m in the middle layers. The size of the turbid bottom current did not differ significantly between observations before and after the typhoon. Surface visibility calculated from satellite data also decreased by 20–30% compared to that before the typhoon.

Choi, J.H.; Kin, S.D.; Jun, K.W.; Lee, H.J., and Tak, W.J., 2020. Analysis of the topography change using the RAMMS Model and numerical modeling in the Korean East Sea Estuary. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 422–427. Coconut Creek (Florida), ISSN 0749-0208.

Recently, erosion and sedimentation imbalances have occurred on many coastlines due to the complex effects of man-made environment changes and natural environment changes caused by climate change. Problems including coastal erosion, shoreline topography changes, and estuary blockages require comprehensive management of sediments including coastal sediments and those discharged from rivers and mountains in the hinterland. This study quantitatively investigated the streamflow of sediments generated from mountains and examined the effect of discharged sediments on coastlines and beaches. First, the sediments in rivers and beaches from mountain areas were investigated on-site using terrestrial LiDAR. High-precision topography data were constructed by generating Digital Elevation Model (DEM). To calculate the amount of sediment discharged from mountain areas quantitatively by using constructed topography data, simulations were performed with the RAMMS model, a type of sediment-water flow analysis model. By applying an erosion and sedimentation model, the effects on the beach topography along the coast were analyzed. It was confirmed through the RAMMS model that the sediment flowed into the river when a mountainous disaster, such as landslide or debris-flow, occurred. The sediment that flowed into the river induced coastline and beach topography changes. In terms of the beach topography on the East Coast of South Korea, the north side of the estuary beach showed a significant sedimentation tendency and the south side of the beach showed a gradual erosion tendency. Furthermore, significant changes in the coastline were observed as a river-mouth blockage occurred at the estuary due to sediments deposited from the mountains and rivers in the coastal area. It is expected that the results of this study will provide useful information when establishing plans for the preservation of coastal areas in the future.

Choi, T.J.; Choi, J.Y.; Park, J.Y., and Yang, Y.J., 2020. Long-term temporal and spatial morphological variability of a nourished beach using the EOF analysis. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 428–432. Coconut Creek (Florida), ISSN 0749-0208.

Byeonsan Beach located at the west coast of Korea has been eroded seriously since 2006 after the construction of the Saemangeum dike. For this reason beach nourishment has been conducted from 2011 until 2017, and the result was successful by turning the beach in erosional phase of -4.1 cm/yr (2006 to 2010) into depositional condition of +2.0 cm/yr (2011 to 2017). Based on the EOF analysis of sixty-nine beach surveys during 13-year period from 2006 to 2019, the first four modes accounted for nearly 83% of total variability, leading to the interpretations of beach-nourishment effect, artificial construction, the influence of beach ridges migration, and irrigation-channel effect, respectively.

Dai, W.Q.; Li, H.; Chen, X.D.; Xu, F.; Zhou Z.; and Zhang, C.K., 2020. Saltmarsh expansion in response to morphodynamic evolution: Field observations in the Jiangsu coast using UAV. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 433–437. Coconut Creek (Florida), ISSN 0749-0208.

Most studies on the biological features and the morphodynamic indications of saltmarshes focused on individual plant groth, such as the stem height and the biomass. However, the understandings of the the planemetric patterns are limited. In this study, UAV (Unmanned Aerial Vehicle)-based observations are conducted in six saltmarsh areas along the Jiangsu coast, China. 3D point clouds, consequent DEM (digital elevation model) and colour orthomosaics are generated using the SfM (Structure from Motion) techniques. We track the variations in the locations of the saltmarsh front as well as the sizes and the distributions of patchs. The saltmarshes are distributed as a whole piece in the landside, while they turn to scattered patches to the sea. We find the locations of the saltmarsh front as a function of bed elevations and season. The area of a single patch is between 0 and 90 m². The number of the patches increases then decreases from landside to the seaside. For tidal flats in progradation, saltmarsh slowly expands seaward following the sediment accretion. This study highlights the abilities of the drone and the SfM technologies to measure the salt marsh distributions, and further to analyze the geometric characteristics and biomorphodynamics of tidal saltmarsh flats.

Silva, A.P.; Woortmann, L.G.; Vieira da Silva, G., Murray, T.; Strauss, D., and Tomlinson, R., 2020. A 90-year Morphodynamic Analysis in Southern Queensland (Australia). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 438-442. Coconut Creek (Florida), ISSN 0749-0208.

This paper investigates the beach morphology changes in response to coastal structures and wave conditions on the Southern Gold Coast region (Letitia Spit, NSW to Kirra Beach, QLD). To do so, 137 individual days – spanning approximately 90 years (1930 – 2017) - were analysed using remote-sensing. Images were rectified and mapped in ArcGIS 10.3, identifying sandbars, spit formations, shoreline indicator and the river delta. The analysis showed long-term trends in response to the major coastal interventions (training walls and artificial bypassing). In general, the beach equilibrium was reestablished in ∼10 years after the interventions, even though this condition could mean a complete upper beach depletion. Both the river and headland bypassing systems presented changes as results of the anthropogenic structures and to natural stressors. For instance, to have a natural recovery of Point Danger bypassing, the river delta would need to rebuild, and a continuous increased longshore transport would be necessary. These conditions were observed during strong El Nino years. In addition, the bypassing systems within Coolangatta Bay showed that sediment deposits location and seasonal wave variability control the type and occurrence of the bypassing. Overall, the study proved the complex interconnection between coastal compartments that is essential to understand for having an effective coastal management. The knowledge of long-term morphodynamic processes gained with this approach can support coastal cities to maintain healthy and resilient beach systems.

Del Río, J.L.; Malvárez, G., and Navas, F., 2020. Reservoir lake effects on eroded littoral systems: The case of the Bay of Marbella, southern Spain. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 443-447. Coconut Creek (Florida), ISSN 0749-0208.

The Bay of Marbella, in Western Costa del Sol (southern Spain), is one of the most artificialized coastal areas of the Mediterranean. Environmental factors, such as geology and climatic conditions, have supported a great variety of industrial activities over time. However, tourism industry positioned Marbella as an internationally renowned destination demanding the rapid artificialisation of its hinterland between the 1970s and the 1990s, relying such process on natural resources -mainly water- for urban sprawl. Small reservoir lakes were constructed in the 19^th century for iron melting and irrigation industries, but the greatest water management infrastructure for the development of the tourism industry, La Concepción Dam, was constructed in the 1970s in the lower reaches of the Rio Verde, the main river in the area. Although a significant amount of water is stored in the dam, the presence of steep slopes and the likely occurrence of heavy rainfall during winter generate torrential water runoff with high energy and high rates of sediment yield. The dam performs as a sediment trap and has induced the annulment of the main source of sediment supply to the littoral system, inducing severe coastal erosion processes which have not been successfully tackled yet. This paper presents a first order estimate of sediment yield in the Río Verde watershed introducing sediment budget stored within La Concepción reservoir. Results show that potential high sediment yield rates estimated in the Rio Verde watershed might have reached La Concepción Dam and might have contributed to the siltation of the reservoir lake and direct coastal erosion. Whilst recognised as the main culprit, no action is undertaken by the decision-makers to extract and reutilise sediments silting coastal dams.

Del Valle, L.; Timar-Gabor, A.; Fornós, J.J., and Pons, G.X., 2020. Lower to Upper Pleistocene coastal deposits from Ses Salines, the Es Freus Islets and Cala Sabina (Pityusic Islands, Western Mediterranean): Chronology and evolution. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 448-452. Coconut Creek (Florida), ISSN 0749-0208.

Coastal areas are dynamic territories that are subjected to the confluence of many factors and agents that are causing transformations. These modifications and their causes can be identified from the geomorphological evidence. The study of the Pleistocene deposits of Pityusic islands can provide a very good source of information for gaining better knowledge onthe history of the climate and envirnomental conditions, as well as the geomorphological processes that occurred during the Quaternary. In this study we present the sedimentology and stratigraphy of the Pleistocene materials cropping out in the Ses Salines (Eivissa), the Es Freus islets -between Eivissa and Formentera Is.-and Cala Sabina (Formentera). Five major sedimentary facies are described, presenting the succession of aeolian colluvial and edaphic environments. The Optically Stimulation Luminescence (OSL) dating of aeolian levels and edaphic levels indicates that their deposition took place between Lower to the Upper Pleistocene. The sedimentological and chronological analysis of these deposits allows to reconstructed the coastal Pleistocene environmental history form MIS 16 to MIS 5.

Dillenburg, S.R.; Barboza, E.G.; Rosa, M.L.C.C.; Caron, F., and Bitencourt, V.B., 2020. Changes in the littoral drift of the Uruguayan coast during the Holocene and its influence in the continuing erosion in southern Brazil. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 453–457. Coconut Creek (Florida), ISSN 0749-0208.

In northern Uruguay and southern Brazil, a littoral drift system dominates from southwest to northeast. This littoral drift is a consequence of higher wave-energy, generated in southern latitudes and that has been operating on a long-term scale, playing an important role not only in the evolution of coastal barriers of this region during the Holocene but also in coastal erosion that presently occurs in some parts of this coast. From La Coronilla to Cabo Santa Marta, which is a coastal sector 750 km - along the coast is gently undulating, showing gentle projections located to the south of gentle reentrances, that are dominated by transgressive/stationary and regressive barriers, respectively. In general, the regressive barriers have been developed by sediments brought into the reentrances by long-shore currents. The main source of these sediments had been the transgressive/stationary barriers that occur along the coastal projections. This differentiation of barrier behavior started at around 6-5 ka, at the end of the Postglacial Marine Transgression (PMT), when all rivers were drowned, finishing the delivery of new coarse sediments to the coast. Also, at this time the large rock promontories of the Uruguayan coast were formed and started to retain sediments of the littoral drift system, triggering a long-term coastal erosion in the southernmost coastal projection. Regarding erosion that is occurring in this stretch of coast the important issue to be considered in future coastal planning is that erosion will continue to operate in the long-term but will also be (and certainly has been already) amplified by sea-level rise in the next centuries as projected by the Intergovernmental Panel on Climate Change (IPCC).

Diniz, M.T.M.; Silva, D.S.; Santos, J.R.; Souza, R.M., and Silva, J.P., 2020. Variation of the coastline between the years of 1984 and 2017 in the State of Sergipe, Northeast Region, Brazil. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 458–462. Coconut Creek (Florida), ISSN 0749-0208.

The variation of the coastline has become one of the most significant issues for urbanized coastlines in the world, being considered a problem for society, due to the occurrence of erosion in beaches occupied by men. In Brazil, there is a predominant tendency for beach erosion. However, on the coast of the State of Sergipe, Northeast Region in Brazil, dynamic stability predominates in most beaches. The coast in Sergipe has sandy beaches, exposed to the ocean and they are interrupted by the river mouths. The objective of this paper was mapping and presenting the dynamic evolution of the Sergipe coastline between 1984 and 2017, in order to identify areas of erosion, accretion and dynamic stability. The delimitation of the coastline was performed in November 2017 using the Trimble R6 geodetic GPS, the PPK (post-processed kinematic) positioning techniques were applied. The current coastline was compared to another, drawn from 1984 Landsat satellite images, with a spatial resolution of 30 m, sectors where erosion or accretion occurred were delimited. Areas with 30 meters of variation or less were considered dynamically stable, their variation may be related to the resolution of the image from 1984. The mapped coastline has 152, 3 km of linear extension, from which 6, 8 km are river mouths. From the remaining 145, 5 km, 52, 2 km or 34% are subject to erosion, 79, 4 km or 52% are in dynamic stability and 13, 8 km or 9% are in a progradation system. Part of the erosion area is occupied by villages. These findings will help governors and concerned parties to develop strategies for adaptation against losing stretches of land.

Dolphin, T.; Burningham, H.; Sifnioti, D.; Manning, W.; Wallbridge, S., and Farcas, A., 2020. Mixed sand/gravel beach response to the Beast from the East storms. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 463–467. Coconut Creek (Florida), ISSN 0749-0208.

Two large, very long-duration, shore-normal (easterly) storms worked on the Minsmere – Sizewell mixed sand and gravel (MSG) beach frontage (Suffolk, UK) in March 2018. These storms were unusual in their sustained high waves (Hs > 2.1 m, 97.5^th percentile) for 140 hours from the east (16% occurrence), compared to the regional median duration of 8.5 hours per storm. Patterns in contour advance/retreat were compared with modelled nearshore wave conditions every 100 m along the 3.3 km frontage. Although there was a positive correlation between the upper supra-tidal beach and wave period, patterns in the beach response were inconsistent and zones of common behaviour could not be explained by the wave data. Postulated explanations include spatial variation in the antecedent morphology and particle-size arrangement within the MSG sediment matrix. Despite the high magnitude of work done by these storms, the lack of barrier erosion suggests that barrier stability is likely for the present sea level under these perceived more-erosive, though less common, easterly storms.

Feng, X.; Dong, B.X.; Ma, G.F., and Feng, W.B., 2020. Topographic and hydrodynamic influence on rip currents and alongshore currents on headland beaches in China. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 468–473. Coconut Creek (Florida), ISSN 0749-0208.

Headland beaches are one of the most typical beaches in southern China. Meanwhile, southern China seas experienced severe rip current hazards. In this paper, numerical simulations were carried out by utilizing Delft 3D Flow-Wave coupling model. Ideal topography of different headland beaches was established and the variabilities in the rip currents' forms and the hydrodynamics from the major headland beach patterns were discussed, including the relative headland length (α= L_head/L_beach), the curvature of shoreline (k = L_s/L_c), the wave direction (θ) and the wave height (h_s). Results revealed that four factors, including α, k, θ and h_s, all have some influences on the nearshore circulation. The shape of the coastline influenced the position of alongshore current and the appearance of headland rip. The length of headland and the wave height influenced the intensity and the spatial distribution of nearshore circulation mainly. Besides, wave direction was the most important factor for channel rip. Because it played a decisive role in the generation of channel rip.

Oliveira, J.F.; Scarelli, F .; Manzolli, R.P.; Portz, L.; Barboza, E.G. 2020 Geomorphological responses due to storm wave events at Praia da Barra, Garopaba – Santa Catarina State, Southern Brazil. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 474-478. Coconut Creek (Florida), ISSN 0749-0208.

This work presents a beach morphodynamics analysis for Praia da Barra, located in the municipality of Garopaba, Santa Catarina State, Brazil. Praia da Barra has sectors with a natural beach/dune system and sectors where the foredune is completely anthropized. In 2017, during autumn and winter, eight storm wave events reached the study area, resulting in a coastline retreat and infrastructure damages at the site and along the southern Brazilian coastal zone. This work applied two methodologies to study the impacts of storm waves at the study area, 1) Four photogrammetric surveys using UAV high-resolution Orthophoto and DEMs for monitoring geomorphological changes at the site, before and after storm wave events in 2017; and 2) wave simulation using the SMC-Brazil platform to assess wave and current patterns from three main wave directions scenarios. The authors integrated the results from both methodologies to understand the behavior of Praia da Barra's beach/dune system when attacked by storm wave events. The authors identified erosive hot spots at Praia da Barra that are concentrated at the central sector of the beach, which presents more anthropization. While the northern and southern sectors present a vegetated and well-developed foredune system, they also presented a higher resilience against the storm events that hit Praia da Barra during the autumn and winter seasons of 2017.

Fernández-Fernández, S.; Silva, P.A.; Ferreira, C.C., and Carracedo-García, P.E., 2020. Longshore sediment transport estimation at Areão Beach (NW Portugal) under climate change scenario. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. (Seville, Spain). Journal of Coastal Research, Special Issue No. 95, pp. 479-483. Coconut Creek (Florida), ISSN 0749-0208.

The knowledge of longshore sediment transport is essential to understand coastal systems morphological evolution, and consequent erosion/accretion processes. This research is focused on Areão Beach, a groined sandy beach, located southwards of Aveiro Lagoon (NW Portugal). The high energetic wave climate and coastline orientation induce a substantial southward net sediment transport rate. Nevertheless, this transport is interrupted by coastal defense structures resulting in erosion problems downdrift. Future changes in wave and storm climate can alter current patterns of coastal erosion. This contribution aims to characterize the longshore sediment transport rate under a future wave climate scenario. The Delft3D-WAVE module propagated wave spectral data for historical and future, corresponding to climate change scenario RCP8.5. The hydrodynamic parameters (significant wave height, peak wave period and wave direction) were extracted at offshore Areão Beach and linear wave theory was applied to obtain significant wave height and wave direction at breaking point. Then, CERC empirical sediment transport formula re-evaluated in 2013 was used to estimate longshore sediment transport values. The results disclose a change in the magnitude of longshore sediment transport and an intensification of northwards transport in the future. These findings can contribute for an adequate decision-making regarding beach erosion management.

Kupfer, S.; Ferreira Ó., and Costas, S., 2020. Assessment of overwash-induced flooding at two beaches along the southwest Algarve, Portugal. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 484–489. Coconut Creek (Florida), ISSN 0749-0208.

At the Algarve south coast overwash-induced floods are a frequent and destructive phenomenon. In this study return periods for overwash potentials are estimated for two beaches located at the southwest coast of the Algarve (Carvoeiro and Salema) based on runup calculations for the period 1995-2017 after applying two well validated empirical formulations. Results show that overwash potentials are high even for small return periods. Additionally, the suitability of two different indicators (overwash potential and overwash depth) has been tested to represent the flood extent. Results suggest that the flood extent derived from the overwash depth presents several limitations and cannot realistically represent observations, while the flood extent given by the overwash potential (using a simple bathtub approach) fairly represents the overwash-induced flood, even though it can over/underestimate the flood extent for gentle/steep inland slopes. Flood extents derived from the overwash potential, for return periods of 10- and 100-year, show that occupied areas are potentially flooded for both return periods. It is therefore necessary to define appropriate adaptation measures for both beaches, preferably based on detailed risk assessment.

FitzGerald, D.; Ryerson, O.; Hughes, Z.J.; Black, S.; Georgiou, I.; Hein, C., and Novak, A., 2020. Long-term variability in inorganic sediment contribution to the Great Marsh, Massachusetts. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 490–494. Coconut Creek (Florida), ISSN 0749-0208.

In New England, the marsh platform sits above mean high water and is flooded about 8 times a month. This high marsh, dominated by Spartina patens, has a vertical accretion rate of ∼2.5 mm/yr, significantly lower than the 6-7 mm/yr accretion rate of low marsh, dominated by Spartina alterniflora. Accelerating sea-level rise will eventually cause the high marsh to transition to low marsh; the rate of this change is controlled, in part, by the contribution of inorganic sediment. Temporal and spatial variability of inorganic marsh sedimentation during the past ∼ 2.5 ka was examined at the Great Marsh, Massachusetts, using twenty cores, each ∼180-cm long, along five transects. Transects were aligned perpendicular to bays and major channels at different compass quadrants to assess influences of wind and tidal flow during storms. Cores were sampled every 20 cm to determine percent organic matter (loss on ignition) and grain size distribution (using a laser particle size analyzer). Data show a weak correlation for grain size versus distance from the nearest channel or bay. Additionally, no consistent vertical trends in grain size were observed, either within individual sampling sites nor among coring transects. Instead, we find coarsening upwards trends at some sites, likely due to increased channelization and tidal velocity as the marsh matured. Elsewhere, sediments fine upwards in response to deepening bays and channels. Finally, transects exhibiting variable grain size trends are likely influenced by ice rafted sediment. These results demonstrate the complexity of sedimentation on the marsh platform and the challenge in accurately predicting patterns of sediment transport using a single suspended grain size in hydrodynamic models in these systems.

Garlan, T.; Almar, R.; Gauduin, H.; Gosselin, M.; Morio, O., and Labarthe, C., 2020. 3D variability of sediment granulometry in two tropical environments: Nha Trang (Vietnam) and Saint-Louis (Sénégal). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 495–499. Coconut Creek (Florida), ISSN 0749-0208.

The sediment variability of two tropical beaches was studied in order to provide the input data of the COASTVAR project's morphodynamic models. The longshore, cross-shore and vertical sediment organization of the first decimeters seems important to take into account in modeling. In particular, the presence of coarser underlying sediments, very frequently observed at all latitudes, may be at the origin of the slope of the beach. And these coarser sediments can also cause significant changes in sedimentary dynamics, when the most energetic events come to set them in motion. But the 3D characterization of beach sediments is not easy and the methods to achieve it are presented here.

Gontz, A.; McCallum, A.; Ellerton, D.; Patton, N., and Shulmeister, J., 2020. The Teewah Transect: GPR-Derived Insights into the Younger Dune Morphosequences on the Great Sandy Coast, Queensland, Australia. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 500–504. Coconut Creek (Florida), ISSN 0749-0208.

The world's largest sand islands lie off the coast of southeast Queensland, Australia. Between these islands, mainland coastal sand masses, bedrock promontories and rivers exist in low-lying areas. Sediment is sourced from one of the world's longest downdrift systems, transporting sand eroded from sandstones in New South Wales north over 1000 km. Recent work has shown the coastal dune fields have been periodically active for the last million years, at times of high and intermediate sea-levels, and identified a series of aeolian morphosequences that exhibit an onlapping relationship with evidence of significant reworking of more seaward morphosequences to create more landward low-relief aeolian landscapes. In 2012, a campaign that collected over 300 km of ground penetrating radar data was begun to understand the stratigraphic framework of this sand-rich system.. One of the surveys acquired a transect over the dune environment of the southern tip of the Cooloola Sand Mass near the town of Teewah. At this location, the dune field narrows to less than 1.5 km with 20-25 m of relief. The seaward side is characterized by eroding dunes and high bluffs. Moving inland over the highest portion of the dune field, the landscape slopes gently to a near sea level with a pluvial-fluviallacustrine dominated system that drains directly to the Noosa River and the Coral Sea. GPR surveys revealed a complex stratigraphy including primary sediment structures related to aeolian processes overprinted with podzol soil development resulting in post depositional features that range from well-developed soil sequences to incipient horizons. Recent GIS mapping has identified this area as consisting of primarily Holocene systems. The Teewah Transect is presented as a case study demonstrating a spatial relationship of the morphosequences and examines the aeolian-soil relationships at the far southern tip of the Cooloola Sand Mass.

Grottoli, E.; Cilli, S.; Ciavola, P., and Armaroli, C., 2020. Sedimentation at river mouths bounded by coastal structures: A case study along the Emilia-Romagna coastline, Italy. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 505–510. Seville (Spain), ISSN 0749-0208.

Beach retreat in the Emilia-Romagna coast, facing the north Adriatic Sea, is well-known since decades and several factors are behind this phenomenon: a scarcity of natural sediment supply by rivers, natural and anthropogenic subsidence, and a strong urbanization of the coastal zone. Several bedload measurement campaigns in one representative river of the Ravenna province (Savio River) have been carried out since 2017. At the same time, seasonal surveys of bathymetry were undertaken at the river outlet to correlate changes in sedimentation with river input. The river mouth is constrained by artificial embankments that possibly funnel out sediment offshore during river floods. However, monitoring of bedload transport correlated with bathymetric changes between July 2017 and November 2018 still found a positive budget of almost 5000 cubic meters. Local authorities in Ravenna are planning to dredge 20000 cubic metres from the river mouth to supply small nourishments outside the studied coastal cell. According to the measurements of bathymetric changes, the Savio mouth will need almost six years to recover, assuming the occurrence of a particularly efficient rate of sediment transport, like the one observed in the monitored period. Notably, the analysed period included a very large river flood that could overshadow the modal sediment transport operated by the river. Furthermore, with deepening of the mouth, the two villages adjacent to the outlet are likely to become more exposed to sea flooding, due to the propagation of surges inside the river mouth. The paper concludes that dredging activities should be reconsidered in view of the precarious equilibrium of the system.

Hong, S.-H.; Chun, S.S.; Kim, J.-C.; Lee, G.-S.; Yoon, H.-H., and Yoo, D.-G., 2020. Sedimentary facies and depositional environment of long sediment cores from the Nakdong incised valley fills, southeastern Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 511–515. Coconut Creek (Florida), ISSN 0749-0208.

Two deep-drilled cores were obtained from the Nakdong River delta in 2016. Based on the sediment structure, composition and texture, the deposits can be divided into four depositional units: I) fluvial sediments, II) estuarine sediments, III) coastal sediments, and IV) delta sediments. The lowermost Unit I is about 25 m thick and comprised clast-supported gravel and massive sand. The age dates of the upper part of Unit 1 is 49.7 ± 5.3 ka. Unit II consists of thin silt laminations that vary rhythmically in thickness, suggesting tidal influences in the estuarine environment. The age dates of this unit range from 10.9 ± 0.18 to 9.6 ± 0.11. Unit III is composed of cross-bedded sand, which contains peat materials and shell fragments and is interpreted to rapidly deposited sand bars in coastal environment. The age of Unit III had 9.7 ± 0.18 ka. Unit IV is composed of extremely bioturbated sandy mud and cross-laminated sand. The age dates of Unit IV ranges from 7.4 ± 0.5 to 0.8 ± 0.09 ka, the deposits belonging to the Holocene. These results indicate that depositional units in the study area consists of fluvial deposits of forced regression formed during the MIS 3, estuarine to tidal flat deposits during deglacial transgression, prograding delta deposits during postglacial periods.

Jun, K.W.; Kin, S.D.; Lee, H.J., and Choi, J.H., 2020. Monitoring of morphological changes in an estuary based on time-series analysis of sediment discharge using a hydrophone. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 516–521. Coconut Creek (Florida), ISSN 0749-0208.

The purpose of this study is to predict the littoral transport rate and morphological changes of estuaries by measuring the discharge of sediments from rivers into the sea in a time series using a hydrophone. To identify the problem of longshore sediments, an understanding of waves and currents is necessary. However, the runoff characteristics of sediments in river estuary that serve as the main source of sediments should be grasped first. It is important to predict the discharge of sediments from rivers into the sea and understand the coastal processes involved in the formation of sandbars in the estuary and the transport of sediments to coastal waters. The selected study area was the Gagok River located in the East Coast of Korea, where periodic estuary occlusion occurs due to the behavior of rivers and waves. This study investigated the morphological changes in the estuary according to the changes in sediment discharge. The sediment discharge was measured using a hydrophone capable of measuring the continuous sediment transport from the acoustic information based on the movement of the sediments. Based on this method, the hydrophone was applied to the field, and measurements of major rainfall events were taken to investigate the influence of changes in sediment discharge on the morphological changes in the estuary. In addition, to verify the results, the morphological changes in the estuary were linked to the ground LiDAR data measured over several years. The results of the survey confirmed that the occlusion phenomenon of the Gagok River estuary occurred according to the seasonal changes. Except for the flood season, there was a small amount of runoff through the river. As a result, a sand barrier developed in the estuary due to the influence of the sediments transported by the waves from the open sea.

Kim, J. and Kim, J., 2020. Estimation of water surface flow velocity using coastal video imagery by visual tracking with deep learning. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 522-526. Coconut Creek (Florida), ISSN 0749-0208.

This paper describes the method of flow velocity estimation of water surface in video imagery by tracking waves using deep neural network for visual object tracking with unsupervised learning. The model of deep neural network consists of two stages for scene separation and image registration to extract waves only and track the propagated waves, respectively. The dataset of video imagery acquired at Anmok beach of south Korea has been used to training the model and it learns the behavior of propagated waves. The performance of model is evaluated by measuring image similarity using test dataset. And the estimated flow velocity of water surface in propagated waves is compared with the flow from conventional image processing method of particle image velocity. The results show that our proposed approach with deep learning method is very promising to measure and predict coastal waves especially in the surf zone.

Kim, H.D.; Aoki,S.; Kim, K.H.; Kim, J.; Shin, B., and Lee, K., 2020. Bathymetric survey for seabed topography using multibeam echo counder in Wando, Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 527–531. Coconut Creek (Florida), ISSN 0749-0208.

Bathymetric survey measures the water depth of the ocean floors accurately. This survey helps produce a nautical chart which is used in numerical simulations, constructions, and more, as well as this project itself. This particular study was conducted to measure the water depth and map the ocean floor of Wando, Korea. With the help of various types of equipment, including multibeam echo sounder, differential GPS (DGPS), motion sensor, gyro compass, and sound velocimeter, bathymetric survey was made possible. Multibeam echo sounder was attached to the boat, emitting a total of 256 beams from a point centered directly below the boat. Water depth data was acquired from the underwater sound velocity using the return time of the beam. DGPS calculated the error value by comparing the position data of the control point at the base station where the position is already known via the Korea Hydrographic and Oceanographic Agency and where the position value is measured by using the receiver of the GPS. Throughout the survey, abnormal bodies were found even after the quality control filtering. These objects were as such classified through further detailed investigation.

Kim, S.-R.; Chun, J.-H.; Um, I.-K., and Cukur, D., 2020. Distribution and characteristics of sandy sediments along the northeastern continental shelf of Korea in the East Sea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 532–536. Coconut Creek (Florida), ISSN 0749-0208.

In this study, the distribution and provenance of sandy surface sediments were investigated along the northeastern continental shelf of Korea. A total of 154 surface sediment samples from river, beach, continental shelf and shelf edge substrates were collected and analyzed for their grain size and mineral composition. Coarse-grained sandy sediments (mean grain size, –1.3 to 1.0 φ) showed that the inner shelf and shelf break were clearly separated by outer shelf silt sediment (mean grain size, ∼5 φ). The mineral composition of continental shelf sandy sediments differed between Gangneung and Donghae sites. Sandy sediments from Gangneung site consist mainly of quartz, feldspar, and mica, whereas those from Donghae site are composed chiefly of opaque minerals, including quartz and feldspar. Differences in mineral composition between the Gangneung and Donghae sites reflect the influence of geology on land. Sandy sediments were supplied directly to shelf edges during the low stand by small rivers, and not mixed by coastal currents.

Knight, J. and Burningham, H., 2020. What controls bedrock shore platform hardness? A field study from South Africa. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 537-541. Coconut Creek (Florida), ISSN 0749-0208.

Bedrock shore platforms are common features along the Indian Ocean coast of South Africa but their properties and controls have not been well reported. This study presents high-resolution evidence for rock surface properties and hardness values from a sandstone platform at Morgan's Bay (Eastern Cape, South Africa) where the relative roles of environmental versus lithological factors on bedrock surface hardness can be evaluated. Results show that there is very little correspondence between rock hardness and either absolute platform elevation or distance from low water position of sea level. Two contrasting conceptual models are proposed to explain these results. One model proposes that a uniform geological control dominates, despite variations in environmental forcing. The alternative model considers that environmental controls such as waves and subaerial weathering do not significantly vary over the platform, despite any differences in platform relief and microenvironment. These different models can be used as testable hypotheses to evaluate the relative controls on, and thus interpretations of, measurements of rock surface hardness on shore platforms.

Latapy A.; Héquette A.; Nicolle A., and Pouvreau N., 2020. Assessing the influence of changes in shoreface morphology since the 19th century on nearshore hydrodynamics and shoreline evolution in northern France: A modeling approach In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 542–547. Coconut Creek (Florida), ISSN 0749-0208.

The shoreface off the coast of northern France is characterized by the presence of numerous tidal sand banks, forming linear shore-parallel or slightly oblique massive sand bodies. Digitization of historic hydrographic field sheets from the French Hydrographic Service (Shom) archives enabled to produce Digital Elevation Models (DEMs) of the seabed morphology at different dates since the early 19th century. Our analyses of bathymetry changes based on differential DEMs showed significant morphological variations across the shoreface near Calais during the 19th and 20th centuries, which are largely due to changes in nearshore sand bank morphology and position. Sand bank mobility can be partially explained by tidal current asymmetry, inducing an elongation and an alongshore migration of this sand body in the direction of the net residual tidal current. Observed changes in shoreface and nearshore morphology attempt to be related with possible variations in hydrodynamics, this paper presenting the results obtained on tidal currents. TELEMAC-2D model was used to simulate 2D velocity field and water depth during a spring and neap tidal cycle over bathymetry grids based on historical bathymetric soundings. Depending on the bathymetric setting, modeling of tidal residual currents revealed notable increases or decreases in residual current velocity during distinct time periods, particularly in nearshore areas, which may lead to seabed erosion where current strengthening is observed through time or conversely to sediment accumulation in areas of decreasing current velocity. These results are consistent with the shoreline changes that occurred during the 20th century, with a correspondence between nearshore areas of decreasing (or increasing) residual current velocity and adjacent shorelines that were affected by seaward progradation (or erosion), suggesting strong links between changes in seabed morphology over the shoreface and shoreline evolution.

Lee, B.-R.; Yoo D.-G., and Lee, G.-S., 2020. Seismic stratigraphy and depositional history of late Pleistocene-Holocene deposits in the Jeju Strait, Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 548–552. Coconut Creek (Florida), ISSN 0749-0208.

In this study, high-resolution seismic reflection profiles and core samples from the Jeju Strait shelf were analyzed to determine depositional and erosional processes that occurred during the late Quaternary. The results show that late Quaternary deposits in the Jeju Strait comprise six seismic units, consisting of a set of lowstand, transgressive, and highstand systems tracts formed since the last glacial maximum (LGM). The study area was mostly exposed during the LGM (>19 ka BP). An incised channel, such as paleo-Yellow and Yangtze Rivers of China and Korean Rivers, was cut across the continental shelf. Unit 1, the lowermost unit, is regarded as channel-fill deposits formed since the LGM. As the shelf was flooded, the depocenter migrated to the inner-shelf and four units (unit 2-5), regarded as transgressive deposits, developed on the shelf. The uppermost unit 6 consists of Seomjin prodelta developed after the recent highstand of sea level about 6 ka BP. The stratigraphic architecture including the six units is controlled by sea-level change, hydraulic conditions, and sediment supply.

Lee, H.J.; Lee, S.H.; Baek, Y.S., and Lim, H.S., 2020. Holocene transgressive sands on the nearshore of a micro-tidal shelf. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 553-557. Coconut Creek (Florida), ISSN 0749-0208.

A beach retreat by the Holocene sea-level rise is commonly observed in shelf environments. To investigate into a consequence of the beach retreat in a micro-tidal shelf, surface and cored sediments were sampled from a coastal area around a stream in the eastern coast of Korea and were analyzed texturally. A coastal stratigraphy is constructed with three units representing fluvial sediments, eolian sands and beach sands in an ascending order. This stratigraphy results from the Holocene transgression. The textural characteristics of the units are compared with those of the surficial samples to determine the origin of surficial sands. As a result, the nearshore sands in the study area are most probably the erosional remnants of the antecedent eolian and beach sands. This study exemplifies the Holocene transgression over a narrow, steep shelf whereby active shoreface erosion left portions of beach sediments behind in small estuarine environments.

López-Ruiz, A.; Garel, E., and Ferreira, Ó., 2020. The effects of high river discharges on the morphodynamics of the Guadiana ebb-tidal delta. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 558-562. Coconut Creek (Florida), ISSN 0749-0208.

This work analyses the role of high river discharges upon the morphodynamics of an ebb-tidal delta at a jettied inlet (the Guadiana river mouth, at the southern border between Portugal and Spain). The analysis is performed using a numerical model to simulate the effects of synthetic single high river discharge events with return periods ranging from 3 to 670 years. This model was calibrated and validated both for hydro- and morphodynamics. Results show that the area with mobile sediment over the delta varies strongly with the magnitude of the river discharge. Events peaking over 7,500 m³/s produce significant bathymetric variations at the delta, including scouring of the inlet channel, along with the offshore migration and volumetric growth of the outer shoal. Observations have indicated that the delta does not recover from these sudden morphological changes. However, the recent strong river flow regulation by dams has limited the maximum river discharges to 2,500 m³/s. Such vanishing of unusually high discharge events has affected both the short-term and long-term morphodynamics of the Guadiana ebb-tidal delta.

Martín, J.A.; Carreras, D.; Pons, G.X., and Almaraz, A., 2020. Shoreline historical evolution (1956-2015) of beaches of enorca (Balearic Islands). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 563–567. Coconut Creek (Florida), ISSN 0749-0208.

Shoreline evolution of 52 beaches from the island of Menorca (Balearic Islands) has been analyzed from 1956 to 2015 using 9 orthophotos. The analysis was done with the GIS tool Digital Shoreline Analysis System (DSAS). The statistical parameters used are Weighted Linear Regression (WLR), the distance in m/y by plotting the shoreline positions with respect to time, Net Shoreline Movement (NSM), the distance between the oldest and the most recent coastlines in meters and Shoreline Change Envelope (SCE), the distance between the furthest coastlines in meters. The result is a medium setback of 4.8 m at a speed of -0.1 m/y. The behavior of the coastline according the typology of the beach has been analyzed, being the most erosive type A (urban beaches), followed by type B (non-urban beaches with vehicle accessibility), with less erosive C-type beaches (non-urban beaches only accessibility on foot). Also the behavior of the coastline has also been analyzed with regard its geographical location and its physiography. Highlights include the beaches of Ponent with strongest erosion processes, followed by the beaches of Migjorn. In contrast, those of Tramuntana are the least erosive. Finally, an Principal Components Analysis (PCA) has been used to analyze the behavior of the coastline using a matrix of 7 variables with 52 observations. The two first factors explain 66.77 % of the variance, where F1 is positively correlated with NSM and WLR, while F2 is correlated with dunar system and foredune. With regard SCE, is negatively correlated with F1, which can be interpreted that high value of SCE are correlated with high erosive value and vice versa.

Morales, J.A.; Sedrati, M.; Boulmirate, O.; Borrego, J., and Carro, B.M., 2020. Measuring dimensions of ship-generated waves in Guadalquivir Estuary banks (SW Spain): Hydrodynamic considerations. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 568–572. Coconut Creek (Florida), ISSN 0749-0208.

Estuaries have always been very important to communities, as they often represent the economic centers of many countries. The estuarine banks, as fetch-limited environments, might be highly affected by some anthropogenic actions. Ship-generated waves are starting to be the subject of several studies in order to understand their impact on coastal environments. These waves might be the leading factor to erosion in estuarine channel margins when traffic is frequent. Guadalquivir is one of the most important estuaries in Spain. It connects an important number of commercial ships to the port of Seville. Along the estuary, bank erosion is highly pronounced which is starting to worry both, landowners and ecologists, since a part of the estuarine channel crosses the marine sector of Doñana natural park. Last years, port of Seville intended to dredge the channel to get the entrance of bigger ships to the port. Ecologists argue that the magnitude of the waves generated by the ships is proportional to the size of the ship. So, the entrance of bigger ships will increase the erosion along the margins. The aim of this paper, is to obtain preliminary data to verify the relevance of this theory through a hydrodynamic survey using wave gauges on the banks and an ADCP in the bottom of the channel to control the modification of waves and currents caused by the ships.

Morales, R.; Borrego, J.; Carro, B.M., and Morales, J.A, 2020. Depositional facies along the banks of Guadalquivir Estuary (SW Spain). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 573–577. Coconut Creek (Florida), ISSN 0749-0208.

The Guadalquivir Estuary is located at center of the Cadiz Gulf. It is an estuary supplied by one of the longest rivers of Spain. The Guadalquivir estuarine channel extends from the town of Sevilla to its mouth in front of Sanlúcar de Barrameda (Cádiz), bordering Doñana National Park along its southeastern margin. Guadalquivir River has an average discharge of 185 m3/s, with a strong seasonal character. This estuarine zone is characterized by a mesotidal range, with a mean tidal amplitude of two meters. Water usually has a high concentration of suspended matter, being one of the most turbid estuaries in the world. The channel margins mainly develop muddy facies with a clearly visible parallel lamination that has been described and interpreted as a result of the alternation between wet and dry seasons and longer climatic cycles. A zonation of the estuary is suggested as a result of the tidal facies distribution.

Mouragues, A.; Bonneton, P.; Castelle, B.; Marieu, V.; Barrett, A.; Bonneton, N.; Detand, G.; Martins, K.; McCarroll, J.; Morichon, D.; Poate, T.; Rodriguez Padilla, I.; Scott, T., and Sous, D., 2020. Field observations of wave-induced headland rips. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 578–582. Coconut Creek (Florida), ISSN 0749-0208.

Most of rip-current field experiments have focused on persistent rips along rip-channeled sandy beaches or transient rips along reasonably alongshore-uniform surf-zone morphology, while experiments on rip flowing against structures are scarce. In October 2018, a 3-week field experiment was performed at Anglet beach, SW France, aiming at examining the dynamics of high-energy rip currents in complex settings. The beach is barred with prominent inherited geology, characterized by the presence of a 500-m headland and a natural submerged reef. A large array of in-situ instruments was deployed to capture the temporal and spatial variability of rip flow circulations, including ADCPs, surf-zone drifters and video monitoring. The latter allowed to identify a wide range of rip-flow patterns. Among these patterns, a high-intensity rip current flowing against the headland was a dominant feature for obliquely incident waves. Such a boundary rip current was driven by the deflection of the longshore current against the headland, peaking at 0.7 m/s (5-min time- and depth-averaged) 800-m offshore in 12-m depth for a moderate storm event with 4-m obliquely incident waves. Very-low-frequency (O(1h) and O(30min)) fluctuations of this rip current were observed around low tide. Measurements of the vertical structure of the rip reveal that the deflection rip was more vertically-sheared as the water depth increases, with higher velocities near the surface, which is typical of a theoretical rip head structure.

Ndour, A.; Ba, K.; Almar, A.; Almeida, P.; Sall, M.; Diedhiou; P.M., Floc'h, F.; Daly, C.; Grandjean, P.; Boivin, J-P; Castelle, B.; Marieu, V.; Biausque, M.; Detandt, G.; Tomety Folly, S.; Bonou, F.; Capet, X.; Garlan, T., Marchesiello, P.; Benshila, R.; Diaz, H.; Bergsma, E.; Sadio, M.; Sakho, I., and Sy, B.A., 2020. On the natural and anthropogenic drivers of the Senegalese (West Africa) low coast evolution: Saint Louis Beach 2016 COASTVAR experiment and 3D modeling of short term coastal protection measures. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 583-587. Coconut Creek (Florida), ISSN 0749-0208.

West Africa's low and densely populated coasts crystallize most of the environmental and societal problems and resulting vulnerability. It is becoming urgent to document this coast and the natural and anthropogenic forces to understand its evolution. Saint Louis is a historic (World Heritage) city located on the Langue de Barbarie, a 10 km sandspit at the mouth of the Senegal River. Because of its location, it is vulnerable (erosion, flooding) to river and ocean variability. This intermediate barred microtidal beach is located in a storm-free intertropical environment, but is exposed to distant oblique energetic waves from high latitudes, causing one of the highest coastal drifts in the world (∼800,000 m³/year). As part of the COASTVAR project, an intensive international field experiment was conducted in Saint Louis from 4 to 13 December 2016 to quantify the natural protective role played by the sandbar, coastal currents and transient exchanges with the inner shelf. Many instruments have been deployed to measure waves, currents, bathymetry and topography. This article provides an overview on the objectives of the experiment, the deployment and the first results of the modeling of coastal protection strategy.

Robin, N.; Billy, J.; Castelle, B.; Hesp, P.; Laporte-Fauret, Q.; Nicolae-Lerma, A.; Marieu, V.; Rosebery, D.; Bujan, S.; Destribats, B., and Michalet., 2020. Beach-dune recovery from the extreme 2013-2014 storms erosion at Truc Vert Beach, Southwest France: New insights from ground-penetrating radar. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 588–592. Coconut Creek (Florida), ISSN 0749-0208.

Foredunes are efficient natural coastal defenses acting as protective barriers during storm events. A striking example is the response of coastal dunes along the Aquitaine Coast (SW France) to the 2013-2014 winter, which was the most energetic winter since at least the mid-20th century in most of the NE Atlantic. The aim of this study is to analyze the (partial) foredune recovery from the 2013-2014 winter at Truc Vert beach using ground-penetrating radar (GPR) and through the coastal dune internal structure. Geophysical data was compared with semi-monthly DGPS topographic data of the beach, UAV-photogrammetry and Airborne LiDAR surveys of the coastal dune. Three main recovery phases were identified from the 2013-2014 winter: (i) aggradation of the upper-beach and dune front-crest during the post-storm summer; (ii) distinct phases of incipient dune-foot development with dune-crest stability during the following year, and (iii) since 2016, aggradation of both dune-foot and dune front-crest tending towards an equilibrium profile. This study shows that GPR surveys, combined with chronological topographic data, is an efficient tool to provide comprehensive understanding of the beach-dune system evolution at a decadal scale. This approach opens new perspectives to document foredune recovery timing and magnitude along sandy coasts.

Nuyts, S.; Murphy, J.; Li, Z., and Hickey, K., 2020. A methodology to assess the morphological change of a multilevel beach cusp system and their hydrodynamics: Case study of Long Strand, Ireland. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 593-598. Coconut Creek (Florida), ISSN 0749-0208.

Characterising the behaviour of highly dynamic and small-scale coastal features is challenging, for lack of a non-intrusive and cost-effective survey methodology that can map coastal features with high spatial and temporal resolution. Unmanned Aerial Vehicles (UAV) are already widely used in coastal research but to date, they have primarily been used as an auxiliary approach for traditional survey methods (e.g. beach profiles). In this study, a methodology is proposed to fully capture the dynamic behaviour of a multilevel beach cusp system. The aim of the research is to establish a method that links the morphological change of these rhythmic coastal features with detailed information of the hydrodynamics in the study area. This is achieved with a UAV system in combination with MIKE 21 Spectral Waves FM Model. Long Strand, Co. Cork in Ireland is used as a case study to evaluate the proposed methodology. Results show that the proposed approach allows to accurately determine beach cusp parameters (i.e. spacing, amplitude, elevation, and depth) and link their high spatial topographical data with the hydrodynamic forces at any given location. Using this survey method in future, coastal research will allow for a better understanding of complex dynamic coastal features and their behaviour over time.

Ogorodov S.A., Aleksyutita D.M. et al., 2020. Coastal erosion of the Russian Arctic: An overview. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 599-604. Coconut Creek (Florida), ISSN 0749-0208.

An overview of 16 sites of coastal erosion monitoring at the fastest retreating key sites across the Russian Arctic was made. All of these coasts are composed by permafrost, creating specific conditions of their evolution and making them very sensitive to sea ice reduction and ice-free period increase along with the temperature growth, resulting from the ongoing climate change. Erosion of permafrost coasts is among the fastest destructive geomorphic processes in the Arctic. For each key area, data from literature on sediment composition, coastal morphology, permafrost properties and climate evolution were collected, assessed and compared. Rates of coastal retreat in the XX-XXI century derived from direct field measurements and processing of remotely sensed data were analyzed; mechanisms and drivers of coastal erosion were estimated. Patterns of spatial variability and temporal evolution of the coasts were suggested. The influence of different factors of coastal dynamics on thermodenudation (destruction of the bluffs during thawing of permafrost and ground ice) and thermoabrasion (erosion resulting from direct contact of waves with the frozen bluff) was estimated.

Oliveira J.N.C.; Oliveira; F.S.B.F.; Freire, P., and Trigo-Teixeira, A.A., 2020. A hybrid monitoring-modelling analysis on the storm induced sediment dynamics of a structure-controlled beach. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 605–609. Coconut Creek (Florida), ISSN 0749-0208.

The main objective of this study is to investigate the effect of sediment flushing on the morphology of artificially embayed beaches using field data and numerical modelling. The sandy stretch of Cova-Gala in the West Coast of Portugal, characterized by a high-energy wave climate, is critical regarding erosion-flooding risks. The site was monitored from August 2018 to February 2019, including the wave climate, the sea level and the beach topo-bathymetric elevation via sonar-single beam, GNSS-RTK and drone surveys. During this period several erosive events caused the retreat and lowering of the upper beach profile. The XBeach model was applied to simulate the morphological evolution during the monitored period using synoptic wave and sea level data as the hydrodynamic forcing. The results of the data-model analysis reveal that i) the alongshore extension of the sedimentological cells and the cross-shore structures length have a relevant influence on the lee-side erosion patterns, which affect the overall surrounding morphology, ii) the model overestimates the scouring of the seawall toe, particularly with the 1D mode; and iii) the beach backshore typology, dune and seawall, has a great influence on beach dynamic processes.

Nicolae Lerma, A.; Paris, F.; Garcin, M., and Dailloux, D., 2020. Sandy stocks on a rocky shore: States and weekly to pluriannual evolutions. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 610–615. Coconut Creek (Florida), ISSN 0749-0208.

In context of rocky coast, sandy stocks accumulated on the beaches can undergo very fast fluctuations. Erosion or deposition processes can be significant even sometimes at the temporal scale of a tidal cycle. Thus, knowledge of the available sediment stocks at the scale of the entire coastal system (from cliffs to subtidal zones) and transit dynamics within the system are fundamental to understand beach evolutions. The study site is located in the district of Bidart on the French Basque coast. The site is characterized by a succession of cliffs, rocky platform, perched and embayed beaches leading to a complex sedimentary dynamics, strongly constrained by the geological context. The longshore and cross-shore migrations of the sediments result of a fluctuating dynamics in time, depending of the tide, the seasonal waves energy, and the waves direction. This study proposes, from the compilation of several dataset and different observation tools (topo-bathymetric surveys, seismic surveys, sediment coring, airborne LiDAR, oblic-photography), (i) several quantification of the available sedimentary stocks at the scale of the coastal system, (ii) an analysis of the morphological evolutions of the subtidal and intertidal zones at interannual, seasonal and at event time scales. These results are discussed with high resolution bottom currents modelling from a phase-resolving non-hydrostatic wave model to identify the hydrodynamic conditions at the origin of the sedimentary movements and potential circulations between the subtidal and intertidal zone. Based on these works a quantified conceptual model is proposed in order to synthesize the complex exchanges between the various compartments of the shore and give new insight to guide a future sediment management plan.

Parnell, K.E. and Smithers, S.G., 2020. Regional and local variability in coastal processes in Torres Strait, Australia, and its importance for climate change planning. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 616–620. Coconut Creek (Florida), ISSN 0749-0208.

In small island states or regions, climate change planning is frequently undertaken at a country or regional level, and it is assumed that problems are common and that remedial actions can be widely applied. Community members observe treatments such as seawalls elsewhere and demand similar interventions even though they may be inappropriate. Torres Strait lies between mainland Australia and Papua New Guinea and has communities on a diverse range of islands including low muddy, coral cay, volcanic and continental island types. Approaches to solving problems caused by changing coastal processes on these varied shorelines are discussed at scales from regional to specific sites. Torres Strait has two distinct wind seasons which influence wave-driven processes and lead to seasonally reversing alongshore sediment transport, with shoreline dynamics also controlled by coastal orientation and the beach / reef flat interactions. The low muddy islands have limited management options, requiring shore protection and elevation. Shorelines on coral cay islands and the volcanic and continental islands change shape seasonally. In these settings, planning must allow for the seasonal shoreline adjustments, with structural treatments to manage longer-term shoreline trends used only to protect high-value assets and important cultural sites where alternative management responses are not possible.

Thomas, T.; Phillips, M.R., and Morgan, A.R., 2020. Maximising the use of disperate beach profile data. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 621–625. Coconut Creek (Florida), ISSN 0749-0208.

In macrotidal environments, temporal variation in exposed spring tidal beach profiles is often used for assessment of morphological change, but variability in data acquisition curtails analysis to the shortest profile length. This paper describes a quantitative method maximising profile length that enables areas of concern reported by means of a traffic light system of red, amber and green. This refined model, originally introduced in 2018, Utilises, limits set statistically using confidence intervals (90%ile and 99%ile), calculated for either side of average beach levels derived from historic datasets. The visual output identifies relative levels of concern and exceedance of normal parameters would trigger higher levels of assessment defined by a predetermined management framework and the management response would vary depending on the coastal environment being assessed.

Murali, R.M.; Reshma, K.N.; Kumar, S.S.; Balaji, S.A.; Raju, D.M.K., and Ramakrishnan, R., 2020. Spatio-temporal coastal morphological changes of Godavari delta region in the east coast of India. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 626–631. Coconut Creek (Florida), ISSN 0749-0208.

Understanding the characteristics of coastal morphology is necessary to analyse the causes of its changes and its consequences. The present study focuses on the satellite-derived and in-situ measurement based changes along the Godavari delta region to estimate the changes of the geomorphologic units. Three years (2017 – 2019) of seasonal observations along the coast of Godavari delta with fifteen beach profiling stations were carried out to estimate the volumetric changes along this coast. Out of these 15 transects, three stations, S2(i), S6(i), and S6(iv), experienced dynamic changes. The station at Odalarevu [S6(ii)], near Vainateyam river mouth, has undergone severe erosion, indicating an overall shoreline change of 670 m. The changes near this river mouth eventually eroded the nearby two stations by 25m³/m and 11m³/m in volume, respectively. Similarly, Chirra Yanam [S2(i)] showed a gradual accretion of 46m³/m in the same period. Shoreline change study from 1973-2019 using satellite images show erosion of 300 m near Vainateyam river mouth, 140m in the intermediate station, and 50 m in Odalarevu beach. An erosion of 70m is also noted in Chirra Yanam. These results are attributed to the combination of anthropogenic and the response of this delta region for the regional and global processes. The combination of in-situ and satellite observation gives a better insight into the quantitative estimate of morphological changes and their response behavior.

Dan, S.; Vandenabeele S.; Verwaest, T., and Montreuil, A-L., 2020. Hydrodynamics versus sediment concentration at the Belgian coast. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 632–636. Coconut Creek (Florida), ISSN 0749-0208.

The most important process for the stability of a coast is the sediment transport, a process which is controlled by the local hydrodynamics. Insight into this process can be obtained by measuring the marine currents and sediment concentration simultaneously at the exact same location. This was the case at the beach south of Ostend harbor (central Belgian coast) where three frames carrying instruments which measure the marine currents (Aquadopp ©Nortek), the waves (AWAC, 4Hz ©Nortek) and the suspended sediment concentration (Optical Backscatter Sensors – OBS, 4Hz ©Campbell) were deployed for in several campaigns, at depths of -3.5 and -6.5m TAW. These instruments measure in bursts of 10 minutes simultaneously every hour for three weeks. The objective of this research is to establish correlation between local hydrodynamics, especially tide and wave induced currents, and the suspended sediment concentration (SSC). The analysis results show that the currents direction (ENE direction during flood, WSW at ebb tide) and velocities are controlled by the tidal cycles during calm weather and strongly disturbed the wave induced currents during storms. The sediment concentration decrease vertically towards the water surface and it has a strong temporal variability, sometimes ranging from near zero to hundreds of mg/l. The peaks in SSC appear to be related to higher waves and the change in currents direction, particularly during the rising tide. The hydrodynamics is controlled by the tide, while wave induced turbulence increases considerably the SSC, mainly during storms and at shallow depths.

Sharaan, M. and Udo, K., 2020. Projections of proper beach nourishment volume as an adaptation to beach recession based SLR along the Nile Delta coastline of Egypt. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 637-642. Coconut Creek (Florida), ISSN 0749-0208.

Beach loss and shoreline recession-based sea-level rise (SLR) is considered one of the most critical coastal issues worldwide. The Nile Delta coastline of Egypt is categorized as a low-lying and sandy coastal area that is prone to impacts of SLR. Beach nourishment is considered one of the most common adaptation strategies for erosion mitigation. Sandy beaches have a significant role in tourism, recreational purposes, and disaster prevention. The projection of proper beach nourishment volume (fill density) as an adaptation to beach loss-based SLR and land subsidence using the Bruun rule were investigated along the Nile Delta coastline of Egypt. The ensemble-mean regional SLR data included Representative Concentration Pathway (RCP) scenarios. Three main steps were applied to estimate the required proper beach nourishment volume. First, the future beach width due to SLR was estimated, and vulnerable areas to shoreline retreat were identified. Second, the targeted beach width to be protected in terms of coastal conservation, tourism purposes, and maintenance of the present beach was proposed based on Egyptian polices. Third, proper sand beach nourishment volume was estimated for four RCP scenarios, when local land subsidence is considered. The results show that the proper volume of beach nourishment required to maintain the beach width along the whole Nile Delta coastline varies from 24.8×10⁶ to 145.5×10⁶ m³ in 2100, with respect to RCP2.6 and RCP8.5, respectively.

Shim, K.T.; Kim, K.H.; Kim, H.D.; and Kwak, K.S., 2020. Analysis on sediment transport system in the East coast of Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 643–648. Coconut Creek (Florida), ISSN 0749-0208.

In an area comprising a long and a monotonous coastline such as that observed along the east coast of Korea, erosion and accretion can occur repeatedly due to seasonal influences; this leads to the formation of an equilibrium for the sediment budget. However, the construction of artificial structures has caused changes in the sediment budget, which has led to unidirectional sediment transport and excessive erosion and accretion. Recently, there has been an increase in the frequency of appearance of high wave groups that are observed for long periods due to a rise in the sea level and the emerging abnormal climate. This has caused large-scale morphological change and is the major factor that accelerates beach erosion. This study monitors a target area wherein a sediment transport was observed to actively occur; this was achieved by using a beach stabilization measure. The variations in the beach profile and the ratio of the sandy beach budget were predicted using the results obtained. In addition, the sediment transport system of the east coast of Korea was examined through comparison with empirical formulas by classifying the erosive and sedimentary beaches. This study also presents the indicators that will govern the topography of Korea in the future.

Solana, G.; Grifoll, M., and Espino, M, 2020. Hydrographic variability and estuarine classification of Inhambane Bay (Mozambique). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 649–653. Coconut Creek (Florida), ISSN 0749-0208.

This study investigates the hydrographic variability and the estuarine classification obtained from a set of field campaign data in Inhambane Bay (Mozambique). In situ measured salinity, temperature and sea-level data, together with Sea Surface Temperature (SST) obtained from GHRSST project, enabled to investigate the seasonal and inter-annual variability of the hydrography of the bay. Inhambane Bay is a bifurcated two-channel bar-built estuary with an along-coast channel of 30.5 km and a secondary channel of 12.5 km. In terms of tidal classification, Inhambane Bay is classified into the meso-tidal category forced by semi-diurnal tides with a Form Number equal to 0.04. The maximum observed tidal range is ∼3.41 m, with mean spring and neap tidal ranges of ∼2.61 m and ∼1.34 m, respectively. Also, the mean salinity profiles are practically uniform (well-mixed estuary) due to the strong tidal forcing being the Richardson Estuarine number below 0.08. The flushing time is estimated between 1 and 3 days. The characterization presented in this research is novel in the region and involves for the first time systematic in situ observations. The conclusions may be useful for similar unexplored areas along the Mozambican coast.

Sous, D.; Tissier, M.; Bouchette, F.; Dodet, G., and Rey, V., 2020. Extreme wave events on barrier reefs: A driver for critical regime? In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 654–658. Coconut Creek (Florida), ISSN 0749-0208.

This paper describes the hydrodynamic regimes reached over barrier reefs during extreme wave events. The study is based on a combined approach relying, on one hand, on an extensive in-situ experiment over the Ouano reef-lagoon system, New Caledonia and, on the other hand, on wave-resolving numerical modeling.

Strzelecki, M.C.; Duszyński, F.; Tyszkowski, S.; Zbucki, Ł., and Kasprzak, M., 2020. Rauk - Forgotten witness of Holocene sea-level change and development of Baltic rocky coastal zone: A pilot geomorphological study in Lergrav raukar field. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 659–663. Coconut Creek (Florida), ISSN 0749-0208.

The Holocene history of Baltic Sea evolution is definitely one of the most interesting and intriguing stories of environmental change in Europe. To date, the key information on changes in sea-level and shifts in the environment associated with climate fluctuations were found in coastal lakes, marshes and wide stripe of barrier-lagoon systems of southern Baltic. Only limited research was conducted along rocky coasts, so characteristic features for Baltic islands from Bornholm, through Oland, Gotland, Fårö, Hiiumaa, Saarema to thousands of isles of Åland Archipelago. Among the most thrilling natural wonders found along Baltic coasts are rauks or raukars, unique limestone stacks—often with humanlike features—that tower above rocky shore platforms in northern Gotland and on Fårö, Gotland's sister island. Raukar coasts are one of the greatest touristic attractions in Sweden and the mythical coastal landscape of northern Gotland and Fårö had inspired many artists, including Ingmar Bergman. Surprisingly, what attracts tourists and artists, have been neglected by geomorphologists and those fascinating landforms still wait for detailed explanation of their origin and preservation. This paper provides insight into pilot geomorphological study of raukar coast in Lergrav, NE Gotland. Schmidt hammer rock tests were applied to characterize the degree of weathering of rock surface of well-preserved notches. The results of notch rock surface resistance and elevation above present sea-level are discussed with recent relative sea-level curves developed in the region.

Su, M.; Gong, Z.; Yao, P.; Pu, J., and Lu, Y., 2020. Investigation on factors of influence on long-term morphodynamic evolution of a multi-outlets estuarine-deltaic system: A case study of the Lingding Bay, Pearl River Delta. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 664–668. Coconut Creek (Florida), ISSN 0749-0208.

Deltas that formed by single river outlets have been widely studied, whereas there are also many deltas that formed by multiple river outlets, deserving more attentions. Compared with the delta which is developed by single river outlet with one or more branching channels, the influence factors and the interaction between outlets are more complicated. In this study, we aim to investigate the long-term morphodynamic evolution mechanism of a compound delta, formed by multi-river outlets simultaneously. This study takes the Lingding Bay of the Pearl River Delta as an example to explore evolution features and factors of influence of such compound deltas. Based on a schematized morphodynamic model, the simulated compound deltaic system shows two main features: dense channel network and asymmetry distribution between the eastern and western parts. The relative importance of several influencing factors has been assessed through a series of scenarios. Results suggest that tidal range is the most important factor on the evolution of compound deltaic system, while the influence of water and sediment discharge ratio of river outlets are ignorable. Pattern of the compound delta exhibits unique features compared to deltas formed by single river outlets. Furthermore, compound deltas developed by multi-river outlets is not the direct overlay of each sub-deltas. The interaction between sub-deltas is important for the development of compound delta and should not be ignored.

Suanez, S.; Stéphan, P.; Fichaut, B.; Ammann, J., and Accensi, M., 2020. Medium-term morphological changes of a gravel spit driving by storm events (Sillon de Talbert, Brittany, France). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 669-673. Coconut Creek (Florida), ISSN 0749-0208.

The Sillon de Talbert (Northern coast of Brittany) is a large 3.5 km-long swash-aligned gravel spit comprising a volume of sediment of 1.23x10⁶ m³. Since 2002, a morphodynamic survey based on annual DEMs, and waves and water level measurements and/or modeling, has been carried out. The 17-year (2002-2019) monitoring program shows that cross-shore sediment transfers reaching 430,000 m³ are dominant, while the longshore sediment transfer -through cannibalization process- is about 52,000 m³. The maximum landward displacement of the spit due to rollover processes reaches –4 m.yr^-1. Storm events control more than 95% of this retreat due to catastrophic overwash/inundation processes that led to the opening of a breach in March 2018. The morphological evolution of the Sillon de Talbert is driven by anthropogenic forcing (i.e., impact of coastal defence structures, cutting off of longshore sediment transport), and natural forcing such as the depletion of the supply of sediment from the platform.

Tak, W.J.; Jun, K.W., Kin, S.D., and Lee, H.J., 2020. Using drone and LiDAR to assess coastal erosion and shoreline change due to the construction of coastal structures. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 674-678. Coconut Creek (Florida), ISSN 0749-0208.

Recently, The construction of structures on the coastal zone near estuaries, which are the supply sources of sediments, causes a variation in the waterway; this induces a change in the surrounding coasts, and the resulting coastal erosion can adversely affect the lives of the local residents. In the case of a balanced sediment flow, the quantity of the sediment deposited on the coast is equal to the quantity of the released sediment. However, an increase in either of the quantities causes an imbalance in the sediment transport; consequently, the sand is either deposited or eroded in the coastal or proximate shore regions. In this study, the changes in the shoreline and Wolcheon Beach region located on the east coast of Korea was monitored between 2010 to 2019 investigate the phenomena of coastal erosion and beach deformation. The shorelines, beach width, and beach profile were primarily monitored by employing a drone and a terrestrial LiDAR. The results showed that the sediments were transported northward in summer and southward in winter until 2010 in Wolcheon Beach; however, this seasonal sediment transport was blocked during 2011–2012 by the construction of coastal structures such as breakwaters, leading to partial coastal erosion and sedimentation. Wolcheon Beach originally had the coastal characteristics of the Korean East Coast region (2010), but the sediment transport changed due to the variations in the waterway by the construction of coastal structures, leading to a significant change in the coast (2011). In addition, the northern beach volume increased with respect to estuary, while the southern beach volume decreased. When the offshore breakwater was constructed, the northward sediment occurred dominantly in the shield area. In particular, the planar layout of the harbor facilities concentrated the waves, which increased the quantity of the northward sediment.

Talavera, L.; del Río, L.; and Benavente, J., 2020. UAS-based high-resolution record of the response of a seminatural sandy spit to a severe storm. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 679-683. Coconut Creek (Florida), ISSN 0749-0208.

Human infrastructures in barrier islands restrict the natural storm-induced overwash needed by these systems to evolve, further increasing their vulnerability in the medium and long term. For this reason, accurate overwash measurements in coastal environments subject to varying degrees of occupation are needed. In this work, two Unmanned Aerial System (UAS) flights were performed over two distinct sectors of a sandy spit located in Cádiz (SW Spain) prior and after the landfall of storm Emma. This storm was a high-energy event that lasted 153 hours,with an average significant wave height of 4 m and a storm peak of 6.81 m., and water levels (tide and surge) of up to 4 m. The images derived from the UAS flights were processed with Structure From Motion (SfM) algorithms using Pix4D software, resulting in high-resolution mosaics and Digital Elevation Models (DEMs) of the study area. These allowed (1) the digitization of the washover deposits in both sectors before and after the storm, and (2) the computation of DEMs of Difference (DoDs), which in turn allowed the analysis of volumetric estimates of erosion/accretion triggered by the significant overwash. The results revealed a nonuniform coastal response between both sectors. The area subject to higher degree of development showed a clear restriction in the onshore delivery of sediment during overwash due to the presence of a channel and a road, the coalescence of the nine pre-existing washovers into a unique deposit of 77546 m², and much higher damage extents and associated recovery costs. In the natural sector, the overwash processes reactivated the three pre-existing washovers (which enlarged their areas up to 200%) with no significant damages reported. These findings serve as examples of coastal responses to future similar hydrodynamic conditions, and suggest that this spit will likely evolve following different trajectories in the long-term.

Terefenko, P.; Giza, A.; Paprotny, D., and Walczakiewicz, Sz., 2020. Characteristic of winter storm Xavier and its impacts on coastal morphology: Results of a case study on the polish coast. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 684-688. Coconut Creek (Florida), ISSN 0749-0208.

Winter storms are an important factor affecting the Polish coast. Short-term water-level variations caused by winter storms significantly alter the coast in the non-tidal Baltic Sea, where extreme water levels depend on the volume of water flowing in from the North Sea. If the Baltic does not have the time to “fill in,” high wind speeds and wave heights are insufficient to cause major damage. Although this phenomenon has been widely discussed in literature, no studies focused on western Poland have comprehensively documented the evolution of both the foreshore and nearshore coastal profile. This paper describes the meteorological and hydrological conditions of the severe storm Xavier, which traversed the Polish coast from December 5–7, 2013, as well as its impacts on the bathymetric and topographic profile of the coast along the pier in Międzyzdroje. Shoreline changes caused by the Xavier storm are compared with the effects of smaller events that occurred in 2014. The results show that winter storm Xavier completely rebuilt the profile of the coast. The foreshore was eroded and beach elevation was reduced by an average of 0.5 m. Accumulation was observed in the vicinity of the water line down to a depth of 1 m. Furthermore, erosion processes dominated in the nearshore section with an average value of 0.27 m and a maximum of 0.62 m, with a small exception at a depth of 2 m. Although the erosion rates caused by Xavier were significant, in some sections they were comparable to the effects of shorter and weaker storms that occurred in the area both before and after Xavier.

Tõnisson, H., Suursaar, Ü., Rivis, R., Tamura, T., Aarna, T., Vilumaa, K., and Kont, A., 2020. Characteristics and formation of a solitary dune belt encountered along the coast of Estonia. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 689-694. Coconut Creek (Florida), ISSN 0749-0208.

Dunes are not particularly high and widespread on practically tideless, prograding coasts of Estonia. The aim of the study was to document characteristics of a single-ridge, up to 10–14 m high, non-continuous dune belt (DB), existing 0.1–1 km landward from the contemporary shoreline. Using LiDAR-based elevation data, landscape profilings, and paleoclimatic proxies, its age and formation mechanism were studied. The results suggest that the DB is different and independent from adjacent aeolian landforms (foredune systems and paleodunes), and it follows the coastline regardless of its exposition at a similar height in more than 30 sparsely located coastal segments. In many cases it is partially reblown to 5–7 m elevation and sometimes it overrides the older well-organized foredune ridges. Based on site-specific land uplift rates and OSL dates, the formation of the dune began at around AD 1300. It gradually grew over most of the Little Ice Age (LIA), when cold conditions inhibited vegetation growth and allowed to release a considerable amount of movable sediment. Major reblow events probably occurred during the cold phases of the LIA from AD 1450 to 1750.

Trogu, D.; Buosi, C.; Ruju, A.; Porta, M.; Ibba, A., and De Muro, S., 2020. What happens to a Mediterranean microtidal wave-dominated beach during significant storm events? The morphological response of a natural Sardinian beach (western Mediterranean). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 695-700. Coconut Creek (Florida), ISSN 0749-0208.

The short-term effects of storm events on the coastline morphology of natural, microtidal, wave dominated beaches located in the western Mediterranean are still poorly documented. Since one of the most visible consequences of a warming climate is an increase in the intensity and frequency of extreme weather conditions, it appears important to know the response of natural and urban beaches to these storm events.

The spatial shoreline variability of a natural Sardinian beach was assessed in our study, based on video camera monitoring data from August 2013 to August 2015 along a 0.3 km stretch of sandy beach. This methodology has been applied in the SW coastal sector of Sardinia where severe storm events mainly related to southwesterly winds (about 50 km/h on average) can induce important morphological changes. These include shoreline retreat/progradation, erosion, beach rotation, reconfiguration of nearshore bars and the deposition of significant seagrass beach-cast litters. Our study showed an erosion and a consequent accretion of the studied beach of about 20 m in two days after the event (SW wind and waves) as a result of the deposition of the Posidonia oceanica beach-cast litter. This morphological response induced by storm events is crucial for coastal managers to plan beach management (for example beach cleaning practice), to prevent coastal risk and to understand the importance of seagrass berm deposition in the formation of natural Mediterranean beaches.

Verwaest, T.; Houthuys, R.; Roest, B.; Dan, S., and Montreuil, A.-L., 2020. A coastline perturbation caused by natural feeding from a shoreface-connected ridge (headland Sint-André, Belgium). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 701-705. Coconut Creek (Florida), ISSN 0749-0208.

This paper explains how a local seaward perturbation, headland Sint-André, in the straight sandy coastline of Belgium can persist for centuries. The diffusive longshore transport gradients on the beach are counterbalanced by a sediment supply from off-shore via a shoreface-connected ridge. A UNIBEST-CL+ 1D coastline model is set up to describe the genesis of this coastline feature. From the size and shape of the perturbation and taking into account the diffusivity caused by the longshore transport gradients, the average sand supply from offshore is estimated to be 55,000 m3/year and it is hindcasted that the connection of the ridge to the coastline occurred between 300 and 400 years ago.

Vieira da Silva, G.; Hamilton, D.; Murray, T.; Strauss, D.; Shaeri, S.; Faivre, G.; Silva, A.P., and Tomlinson, R., 2020. Impacts of a multi-purpose artificial reef on hydrodynamics, waves and long-term beach morphology. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 706-710. Coconut Creek (Florida), ISSN 0749-0208.

Multipurpose Artificial Reefs (MPARs) are structures placed in the nearshore to protect the coast, enhance surfing conditions and ecology. Narrowneck reef is the first MPAR aimed to protect the coast with secondary goal of enhance surfing. Since then, few other structures such as Narrowneck have been deployed and limited data is available in terms of their performance. This paper looks into the impacts the reef has on hydrodynamics, waves and morphologic changes. The results indicate that the reef acts as a hold point deflecting the longshore currents and changing the sediment pathway which resulted in morphological changes observed over longer term. Whilst expected during the design phase of the reef a long-term salient is not observed in the historical record. The primary reef impacts are observed underwater where an increase of sand volume updrift of the reef is clear. This highlights the importance of analysing the whole profile as opposed to the shoreline changes to assess long-term impact of such nearshore structures.

Villate D. A.; Portz L.; Manzolli, R.P., and Alcántara-Carrió J., 2020. Human disturbances of shoreline morphodynamics and dune ecosystem at the Puerto Velero spit (Colombian Caribbean), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No.95, pp. 711-716. Coconut Creek (Florida), ISSN 0749-0208.

Evolution of present coastal environments is controlled by both natural processes and anthropogenic activities, last one causing global, regional and local disturbances. This study analyze the effects of shortage of sediments from Magdalena River and tourism development in the recent shoreline morphodynamics and dune vegetation structure of the Puerto Velero spit, in the northern Colombian Caribbean coast. Shoreline position, dune vegetation and human occupation were taken from the interpretation of satellite images, aerial photographs and field trips. Three methods were applied to analyze shoreline migration. It allowed to deduce trends of very high erosion for the outer neck and moderate to high erosion for the inner neck, while the northern border and the point of the spit present an erosional trend in the outer and inner. Therefore, the outer neck and iner neck show predominance of an erosional trend, more intense for the outer one, while the northern border and particularly the point of the spit present trends of high and very high accretion. It implicates a present progradation of the spit, but a narrowing of its neck. The shortage of coastal sand due to the construction of a jettie at Magdalena River favored the formation of the spit by the erosion of the extinct Isla Verde barrier island, but currently cause erosion of the neck. Erosion of the outer and inner neck is also due to the impact of local disturbances on the backshore and dune system, mainly a rapid increase of occupation and a large circulation of people and vehicles. Dune vegetation distribution is affected by these disturbance, including the presence of invasive aloctonous Calotropis procera over a large area of the dune field. The natural climatic oscillations, particularly the negative El Niño Southern Oscillation (ENSO) events, also favor the progradation of the spit. The analysis of these disturbances on the present geomorphological and ecological evolution on the spit constitutes an important instrument for coastal management.

Wang, L.; Yu, Q.; Zhang, Y., and Gao, S., 2020. Morphological characteristics of low-angle dunes on a tidal ridge, the Jiangsu macrotidal coast, China. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 717-721. Coconut Creek (Florida), ISSN 0749-0208.

Subaqueous dunes are typical flow-transverse rhythmic bedforms in fluvial, intertidal and marine environments. The low-angle dunes (LADs), commonly associated with a leeside angle of less than 15°, differ in terms of the formation mechanism from the high-angle dunes (HADs). Here, multibeam echosounder exploration and seafloor surficial sediment sampling were carried out on a tidal sand ridge off the Jiangsu coast, China, a macrotidal area with the spring tidal range exceeding 6 m. The spatial distribution of the dune morphological parameters, including wave height, wavelength, asymmetry, and lee-side angle, are analyzed in association with the water depth and seafloor sediment. The following results are obtained. (1) Two-dimensional linear dunes are superimposed on the tidal ridge, and a total of 3599 dunes detected are all LADs with an average maximum leeside angle of 5.46°. (2) The spatial distribution of the dune parameters is closely related to the topography of the ridge-swath system. The asymmetries and migration directions of the dunes on the northern and southern slopes of the tidal ridge are opposite, indicating a clockwise residual sand circulation, while the ridge represents the transition zone with relatively symmetrical dunes. (3) Water depth is the controlling factor for the dune geometry in shallow water places. In areas where water depth is below 7.5 m and the seafloor sediments are composed of pure sand, the scales of LADs are proportional to the water depth. (4) Bed sediment composition becomes important for the deeper water areas. For water depth more than 7.5 m, the ratio of cohesive particles (< 8 µm) of bed sediment, which increases with the water depth, inhibits the growth of the LADs. These observations reveal the behavior of LADs in association with sediment particle size and water depth.

Woo, H.J.; Lee, J,-H.; Choi, J.U., and Kang, J., 2020. Changes in sedimentary processes in macrotidal flats in Garolim Bay, West Coast of Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 722-726. Coconut Creek (Florida), ISSN 0749-0208.

Garolim Bay, on the central western coast of Korea, is a semi-enclosed macro-tidal bay with extensive tidal flats that occupy approximately 77% of the bay surface area. The study investigated the sediment characteristics and sedimentation rates to elucidate the spatial and temporal variations in the sedimentary processes in the bay. Surface sediments were sampled to grain-size distributions at 158 stations in July 2002 and July 2014 in the spring tidal cycle. Grain-size distributions were analyzed using standard sieving for the sand fraction and a particle size analyzer for the mud fraction. The geomorphic changes associated with sediment deposition or erosion were investigated along six transect lines on the tidal flats from February 2014 to February 2015 in the ebb tide. The area of sand and muddy sand sediments had extended from the outer to the middle bay in summer 2014, and the percentages of mud were higher in the inner bay compared to the surface sediment distributions in summer 2002. The short-term sedimentation rates from February 2014 to February 2015 showed that erosion was dominant on the tidal flats in the inner bay during spring and on those in the outer bay during winter, with net erosion rates of –1.55 and –55.23 mm/year, respectively. In the middle bay, deposition dominated on the tidal flats, with net deposition rates from 4.85 to 18.94 mm/year. The sediment transport vectors calculated using grain-size parameters for 2002 and 2014 showed that in 2002, sandy sediments were predominantly transported along tidal channels at the bay entrance. However, in winter, sediments from the tidal flats in the outer and middle bay areas are transported to the inner bay by wind-driven waves and tidal currents, resulting in the deposition of sediment on the tidal flats in the inner bay. In summary, the results show that the sediment transport patterns in Garolim Bay changed between 2002 and 2015 due to increased suspended sediment supply and erosion of the tidal flats in the outer bay. Based on these knowledge of sedimentary processes, the major control factors for seasonal variations in sedimentation on the tidal flats in Garolim Bay are tidal currents, wind-driven waves, and sediment inputs.