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AlMashan, N.; Al-Attar, I., and Neelamani, S., 2024. Assessment of annual sedimentation into Failaka Marina (Kuwait) and possible solutions for reduction of siltation. Journal of Coastal Research, 40(3), 527–553. Charlotte (North Carolina), ISSN 0749-0208. Sedimentation is critical for ports, harbors, and marinas, requiring accurate assessment. Failaka Marina in Kuwait is experiencing a severe noncohesive sedimentation problem. The samples collected at the seven locations along the beach showed that the beach has a uniform grain-size diameter, meaning it is poorly graded sand. The sampling at the tip of the southern breakwater showed that the shoaling is mainly sand. The suspended-sediment concentration varies from 0.025 kg m–3 to 1.2 kg m–3, whereas the mean concentration at the marina entrance is 0.85 kg m–3. The time series of the suspended solids over a year in the seawater surrounding Failaka Island shows a range of 8 to 48,069 ppm. Such a considerable variation in suspended load is due to the massive amounts of dredging and spoil disposal at Boubyan Island and Basra Port (Iraq) when a high sediment load moves around Failaka Island with a concentration of more than 40,000 mg L–1. Annual sedimentation is about 2.35 m y–1, which is responsible for blocking the main entrance for navigation. Kuwait's Ministry of Communication allocates $4 to $6 million annually for dredging and disposal activities. This study evaluates the six marina entrance modification scenarios to determine the best scenario that achieves a measurable reduction in sedimentation rate in the Marina. Six marina breakwater modifications were studied, and annual sedimentation rates were numerically computed. The study use Coupled MIKE 21/3 to simulate hydrodynamic conditions for cohesive sediment transport in a problem area. Field data from 2015 calibrated and validated the model. The primary sediment-moving force is SE wind and sea-swell waves. Littoral drift along Failaka Island's southern coastline and high suspended-sediment concentration result in littoral drift and settling. The best scenario showed a 28% sedimentation reduction and a 26% reduction in maintenance dredging costs from the six studied scenarios. [ABSTRACT FROM AUTHOR]

Andrus, T.M. and Bentley, S.J., 2023. Capture timescale of an uncontrolled Mississippi–Atchafayala bifurcation with future lower river strategy implications. Journal of Coastal Research, 39(6), 1001–1020. Charlotte (North Carolina), ISSN 0749-0208. The most recent and currently active delta lobe of the Mississippi River (MR) is the Atchafalaya–Wax Lake lobe, which was initiated approximately 400 years ago as a result of MR stream capture by the Atchafalaya River (AR). This capture process accelerated in the early to mid-1900s but further development was prevented by construction and operation of the Old River Control Structure (ORCS) complex in 1962. Because the initial research to warrant the construction of the ORCS was undertaken nearly 70 years ago, this study revisits the basis of the resulting predictions and evaluates how both branches could evolve moving forward both with and without ORCS controls. This study uses the Delft3D software suite to retest the capture hypothesis by accounting for complex hydrodynamic interactions from the MR/AR bifurcation to the Gulf of Mexico. A 150-year model duration was used to adequately characterize bifurcation evolution, stream capture life cycle, and long-term river management concerns. Results of modeled flow evolution with the ORCS removed indicate a rapid period of channel adjustment followed by a long and gradual increase in flow ranges and magnitudes in the AR similar to those currently in the MR. In this hypothetical scenario, the AR captures 50% of the MR very quickly (∼17 y) to become the dominant stream and then the capture rate begins to decelerate. One-hundred-fifty-year results with ORCS controls remaining unchanged reveal increased sedimentation, rising stages, and decreased stream power in the MR. Conversely, AR results indicate channel deepening, stage lowering, and increased sediment-transport efficiency. These trends suggest that although the flow split at the MR/AR bifurcation continues to be regulated by the ORCS, the geologic evolution toward capture gradually continues. This study presents a long-term view of an uncontrolled MR/AR avulsion, and capture results reiterate the ORCS's importance to socioeconomic factors such as flood control and navigation. However, results also reveal long-term sustainability concerns for the MR system associated with current ORCS flow regulation. Predictive modeling tools such as those developed in this study could be used to optimize ORCS management strategies and potentially enhance ecosystem restoration plans. [ABSTRACT FROM AUTHOR]

Liang, Z.; Ji, D.; Zhang, X.; Lingyun, W.; Zhang, T.; Li, S.; Yong, J.; Luo, J.; Liu, Y., and Zeng, J., 2023. Carboniferous oceanic basin sediment-gravity flows in the margin of the Junggar Basin, NW China: Characterisation and implications for hydrocarbon potential and evolution pacing. Journal of Coastal Research, 39(5), 890–906. Charlotte (North Carolina), ISSN 0749-0208. Several Carboniferous deep-marine-sandstone reservoirs have recently been discovered in the Junggar Basin, NW China. These reservoir sandstones were deposited by sediment-gravity flows that occurred on the continental slope of the Junggar Basin, and they have high hydrocarbon exploration potential. In this study, careful observations and petrological and geochemical analyses of samples from outcrop sections of Carboniferous rocks from the Junggar Basin were conducted to establish the deep-marine sedimentary characteristics, depositional environments, and mechanism of these gravity-flow deposits, as well as a sedimentary model for their occurrence. The deep-marine, gravity-flow deposit types include those of turbidity currents, debris flows, and slumps. The debris-flow deposits can be divided into pebbly debris-flow deposits and sandy debris-flow deposits. Results allow the relationship between the type and nature of gravity flows and ocean basin evolution to be established. During the early Carboniferous, the ocean basin had sufficient space to accommodate incoming sediment, and the sediment transport distance was long. The gravity-flow sediments of this period are dominated by sandy debris-flow deposits and turbidity-flow deposits characterised by thin individual layers but thick accumulations of multiple deposits. With continuous narrowing of the oceanic basin during the late Carboniferous, the basin had a smaller accommodation space. The main types of gravity-flow deposition during this period were pebbly and sandy debris flows, with rare thin turbidity-flow deposits. These deposits were coarser grained than their early Carboniferous equivalents, and their cumulative thicknesses were smaller. The results of the study provide insights into the prediction of deep-marine reservoir sandstones and the distribution of hydrocarbons in the Junggar Basin. [ABSTRACT FROM AUTHOR]

Kim, Y.-j. and Yoon, J.-s., 2023. Shoreline variation prediction of the Jeongdongjin Sea area considering effective sediment volumes. Journal of Coastal Research, 39(1), 154–166. Charlotte (North Carolina), ISSN 0749-0208. The coastal erosion in the East Sea region of Korea has been increasing because of the imbalance in the effective sediment volume and sediment transport from coasts and rivers, which causes intermittent erosion and sedimentation. The accurate prediction of the coastal sediment budget is an extremely difficult task because the sediment transport mechanism on the coast is highly complex. Studies considering the effective sediment volume supplied through rivers remain limited, although many other studies have focused on identifying the characteristics of sediment transport on the east coast. The grain-size distribution of the soil on the coast is considered the single-grain size (D50); however, the grain-size distribution of sediments flowing into and out of the coast and the topographical characteristics of the sea area need to be considered to predict shoreline variation with a high degree of accuracy. Thus, this study conducts in-depth analysis on the changing state of soil movement in wave-current co-existing fields (mountain, river, and coastal areas). The objective is to predict shoreline variation considering the environment of the Jeongdongjin Sea area by establishing a quantitative evaluation system of the effective sediment volume discharged from the area of river mouth bars. An effective sediment volume was evaluated using a sediment runoff model; the wave transformation for each survey line was calculated using SWAN to consider the wave characteristics acting on the sea area. The prediction performance was greatly improved by applying the mixed grain size to the soil in the sea area and by applying jetties to the reefs for upgrading the prediction of the shoreline variation. [ABSTRACT FROM AUTHOR]

Liu, Z.; Zang, J., and Liu, J., 2023. Preliminary analysis of reclamation changes in Macao using multisource and multitemporal remote-sensing data. Journal of Coastal Research, 39(1), 90–102. Charlotte (North Carolina), ISSN 0749-0208. Macao is a typical reclamation city. A systematic analysis of reclamation changes can be used to relate reclamation to socioeconomic development. In this study, multisource and multitemporal satellite remote-sensing data were used to analyze the temporal and spatial characteristics, driving forces for reclamation, and nearshore water quality of Macao. The results showed that the Macao coastline is moving towards the sea. The total area of Macao increased from 29.19 km2 in 1999 to 35.83 km2 in 2019. The largest proportion of reclamation land-use type was public facilities land, whereas the smallest proportion was green land and square land. The land distribution gradually became more compact up to 2007 and dispersed thereafter. The factors of population, gross domestic product, number of visitors to Macao, and total export trade had different influences on reclamation in Macao during different time periods, where the population factor had the largest overall impact. The concentrations of chlorophyll and suspended sediment in Macao coastal waters were high nearshore and low offshore. [ABSTRACT FROM AUTHOR]

Mercaldi, B.; Brideau, L.E.; Tait, J.F., and Griggs, G., 2022. Seasonal morphological variability on estuarine beaches and implications for low-energy beach management. Journal of Coastal Research, 38(6), 1135–1147. Coconut Creek (Florida), ISSN 0749-0208. Estuarine beaches and other low-energy shorelines are critical for habitats and coastal infrastructure protection. Many different species inhabit estuaries because of the water bodies' unique characteristics, such as their mixed seawater and freshwater and variable tidal ranges. Estuarine beaches also have the important role of buffering storm wave energy. Yet, their natural physical processes are understudied. This research focuses on seasonal morphological variability of estuarine, low-energy beaches and evaluates the implications for beach management practices. Five sandy beaches were studied along the northern shoreline of Long Island Sound in the northeastern region of the United States. The studied beaches vary in location, width, length, and orientation within Long Island Sound to represent different exposures to wave energy. Three seasonal profiles were measured at each beach approximately every four months from late 2015 to early 2019 to document topographic changes. The results revealed minimal sediment movement throughout the study period and there was no evidence of significant cyclic cross-shore sediment transport to indicate patterns of seasonal profile changes. These findings reveal important implications for beach management practices on low-energy shorelines. Specifically, estuarine and other low-energy beaches should be studied on decadal time scales to document any long-term variability and post-storm recovery rather than the monthly or yearly time scales on which open-ocean beaches are typically evaluated. Additionally, estuarine beaches and other low-energy shorelines require specialized management practices that cater to their stagnancy to ensure adequate protection of coastal structures and infrastructure in the face of intensifying hurricanes and sea level rise. [ABSTRACT FROM AUTHOR]

Cheng, J. and Wang, P., 2022. Factors controlling storm-induced morphology changes at an erosional hot spot on a nourished beach, Sand Key barrier island, west-central Florida. Journal of Coastal Research, 38(4), 750–765. Coconut Creek (Florida), ISSN 0749-0208. Beach nourishment has become the dominant sandy shore protection method over the past 40 years. The performance of nourished beaches and therefore the design of renourishment projects are significantly controlled by the presence of erosional hot spots and storm impacts. Based on 5.5-year bimonthly beach profile surveys, along a nourished beach spanning an erosional hot spot, this study examines the hydrodynamic conditions of extratropical (winter) and tropical (summer) storms that cause significant morphology changes. The sand volume loss above the short-term closure depth averaged along the 1.8-km stretch erosional hot spot was 178 m3/m over the 5.5 years after the nourishment. A large portion of this volume loss was caused by several extratropical storms and Hurricane Irma in 2017, when the high, northerly approaching waves were associated with a depressed water level. The northerly approaching waves induced a large longshore sediment transport gradient along the generally north-south trending coast due to wave refraction over a nearby ebb tidal delta. The energetic Hurricane Irma induced a large negative surge and also transported sediment seaward beyond the short-term closure depth. On the other hand, during the passages of typical tropical storms, the southerly approaching waves superimposed on elevated water levels caused substantial beach volume loss above the mean sea level. The eroded sediment deposited on the nearshore sandbar, resulting in conserved sand volume above the short-term closure depth. Understanding the different beach response to extratropical and tropical storms would benefit beach management, especially under the circumstance of increasing storm activities due to climate change. [ABSTRACT FROM AUTHOR]

Windom, H.L. and Palmer, J.D., 2022. Changing river discharge and suspended sediment transport to the Georgia Bight: Implications to saltmarsh sustainability. Journal of Coastal Research, 38(3), 512–522. Coconut Creek (Florida), ISSN 0749-0208. Suspended sediment delivered in river discharge to the Georgia Bight (the coastal-shelf area of the SE U.S. Atlantic coasts of Georgia and South Carolina) provides a continuous supply of fine grain sediments to support coastal saltmarshes. Archived data on discharge and suspended sediment loads for Piedmont and Coastal Plain rivers collected over eight to nine decades were used to estimate the present rate of sediment discharge to the Bight to be about 1 × 106 metric tons annually. The data used in this assessment are for the period after major reservoir/dam construction and other streamflow diversions occurring during the 1950s–1970s, which had a major effect on sediment yields of SE Atlantic watersheds. The estimated annual sediment delivery is about two-thirds of that needed to maintain vertical saltmarsh stability as sea level rises at the present regional rate of 3.3 mm/y. The observed 2% per decade decreasing trend in river discharge to the Bight, related to rapid population and temperature rise since ca. 1960, and the continual depletion of sediment stored in river floodplains below dams, suggests that the fine sediment supply to the coast will continue to decline. [ABSTRACT FROM AUTHOR]

Akiner, M.E. and Lačnjevac, C., 2022. Managing saltwater intrusion and agricultural practices along the Boăaçay River, Turkey: Effects from excavation and land source pollution. Journal of Coastal Research, 38(3), 567–577. Coconut Creek (Florida), ISSN 0749-0208. The Boăaçay is a river situated in the Konyaaltı district of Antalya. In 2017, Antalya Metropolitan Municipality implemented a large project in which the river bed was excavated to 1.5 m below sea level. The aquifer is vital for meeting the drinking water needs of the city of Antalya. The goal of this research is to discover the applications that may be made to combat seawater intrusion and nutrient contamination, both of which were brought to the forefront by the Boăaçay Project. In this work, modeling was used to estimate the extent to which agricultural best management practices (BMPs) will be efficient in reducing pollutant load. In BMP modeling with the soil and water assessment tool (SWAT), a decrease of 39%, 38%, and 38% is anticipated in the 5-day biochemical oxygen demand (BOD5), total phosphorus, and total Kjeldahl nitrogen loads, respectively. Sediment accumulated in the channel, and sediment transport occurred on the beach due to coastal erosion. Coastal erosion of up to 25 m was observed from the project's beginning to the present. Substantial land base pollution because of the diffused sources was found. Saltwater intrusion in the Boăaçay River estuary functions as a catalyst in the production of poor odor and appearance, as well as the rapid expansion of algae. The municipality is attempting to remedy this problem by periodic harvesting, which is an overly expensive and ineffective option. Instead, the elevation of the riverbed should be restored to preproject levels to prevent additional environmental and geographic damages. [ABSTRACT FROM AUTHOR]

Youn, S. and Zarillo, G., 2022. Morphological analysis of barrier islands in the Nakdong River Estuary, South Korea. Journal of Coastal Research, 38(3), 475–490. Coconut Creek (Florida), ISSN 0749-0208. The Nakdong Estuary system and the associated barrier island system near Busan, South Korea, consists of dynamic shorelines characterized by morphological transformations that result from natural disasters (typhoons and flooding), rising sea levels, and construction projects (the Nakdong Estuary Dam and the Busan Newport). This study aims to synthesize existing water level, wave, meteorological, and morphological data obtained from various institutions with the objective of identifying major factors that influence shoreline and area change over time. These objectives were met by analyzing the shoreline and area with direction analysis from center point (DACP) to consider the influence of river discharge and sea-level rise and to determine shoreline shifts in barrier island orientation over time. From DACP, it was determined that the Nakdong barrier islands rotated clockwise because of erosion and deposition. Offshore shorelines of barrier islands advanced by 0.1 to 2 km between 1972 and 2013. The area change rate between 1972 and 2013 was 20.85% from 100 to 180° because of the Maenggeummeori-do channel construction and discharge from the Nakdong Estuary Dam. Morphological changes and shifts in shoreline positions were caused by alteration of flow patterns because of construction of the Nakdong Estuary Dam and sea-level rise in the Nakdong Estuary system based on the timeline of the shoreline and area change rates. This study exemplifies the need for a preconstruction development plan in a study area to ensure that the results of a project are environmentally sound with respect to the potential impacts of project construction and sea-level rise. [ABSTRACT FROM AUTHOR]

Black, K.P.; Baba, M.; Mathew, J.; Kurian, N.P., and Ilic, A., 2021. Guidelines to prepare India's coast for climate change. Journal of Coastal Research, 37(6), 1117–1129. Coconut Creek (Florida), ISSN 0749-0208. India's first coastal protection guidelines for climate-change adaptation are described. The guidelines are holistic, recognizing the links between engineering, economic, physical, legal, social, environmental, and governmental intricacies. Robust protection solutions under climate change for millions of coastal residents may occur only when all these facets are improved within the complex regulatory, budgetary, and practical circumstances in India. Fifty-seven specific guidelines are presented in nine categories ranging from administrative to best-practice coastal protection. An "environmental softness ladder" that ranks coastal protection methods was developed as a scientific tool to guide policy development and project implementation. "Minimum floor level" for safe building was defined for each Indian coastal state using climate-change data produced for the study by Indian and international institutes. Beaches are more stable when the net sediment transport fluxes are close to neutral. "Grand schemes," which make large-scale changes to the coast rather than continuing with piecemeal localised works, are recommended. With diverse dynamics over a long coastline in India, the 4-year study engaged an exceptionally large number of experts, agencies, government bodies, development partners, and other stakeholders. [ABSTRACT FROM AUTHOR]

Whitley, A.E.; Figlus, J.; Valsamidis, A., and Reeve, D.E., 2021. One-line modeling of mega-nourishment evolution. Journal of Coastal Research, 37(6), 1224–1234. Coconut Creek (Florida), ISSN 0749-0208. As many coastal areas of the world suffer from chronic erosion, innovative solutions beyond traditional local nourishment must be explored. One such solution is the implementation of mega-nourishments (MNs), where a large sediment volume is deposited in a single location and redistributed via natural processes, thereby feeding adjacent beaches. Robust numerical modeling methods are needed to evaluate potential MN sites at coastal locations around the world. Two one-line numerical modeling approaches of MN evolution are presented using the Coastline Evolution Model (CEM) and GENESIS + Cascade (GenCade). Both models are parameterized for the Sand Motor (SM) that has been constructed on the Dutch coast to explore the feasibility of the MN approach. Here, a variety of K coefficients in the Coastal Engineering Research Center (CERC) sediment transport equation are tested since traditionally calibrated and used values may not apply for MN features. Both models are found capable of reproducing the shoreline morphological patterns observed at the SM over the first 3.5 years. GenCade shows a low difference between measured and modeled coastline position overall, showing accurate predictions of absolute shoreline position. CEM is able to capture feature tip migration due to its wave shadowing algorithm. The best results from both models can be obtained for higher K values than those commonly suggested in the literature. Given the size of a mega-nourishment relative to traditional nourishments, it is likely that a higher-than-usual K value may be a better fit when simulating mega-nourishments in a one-line model. [ABSTRACT FROM AUTHOR]

Spyrou, D. and Karambas, T., 2021. Experimental and numerical simulation of cross-shore morphological processes in a nourished beach. Journal of Coastal Research, 37(5), 1012–1024. Coconut Creek (Florida), ISSN 0749-0208. This paper presents the results of an experimental and numerical research carried out to reproduce the cross-shore evolution of nourished sandy beaches. An extensive two-dimensional laboratory investigation was performed to study the cross-shore profile evolution after the application of a beach nourishment method. A 1:20 scale physical model was carried out in the Laboratory of the Department of Hydraulics and Environmental Engineering, Aristotle University of Thessaloniki. The analysis considered only cross-shore sediment transport. Long-shore sediment transport is considered negligible. Consequently, the obtained results are related to the short-term response of the cross-shore profile. Ten different wave combinations were generated in an attempt to reproduce erosive conditions. Experimental results are given in terms of wave parameters, bed slope, and berm height of the nourished beach. An advanced nonlinear wave model was developed to simulate cross-shore morphodynamical processes. The comparison between the experimental and numerical beach profile indicated good agreement. Also, comparisons between Dean's analytical method and the experimental results were made. [ABSTRACT FROM AUTHOR]

April Le Quéré, P.; Nistor, I., and Mohammadian, M., 2021. Effect of lateral spacing of structures on tsunami-induced scour. Journal of Coastal Research, 37(4), 813–826. Coconut Creek (Florida), ISSN 0749-0208. Tsunamis are a devastating force, as seen by the extreme tsunamis that struck the Indian and Pacific Oceans over the past two decades: the 2004 Indian Ocean Tsunami, the 2010 Chile Tsunami, and the 2011 Tohoku Japan Tsunami. In those events, flood-induced scouring was found to be an important phenomenon that often led to infrastructure damage. Past research has focused on scouring around single columns and other isolated horizontal structures to attempt to understand the complex processes characterizing this phenomenon. However, given that coastal cities often comprise complex arrangements of multiple structures, often crammed, tsunami inundation flow often finds concentrated paths in between such structures; these flow concentrations increase the resulting scouring. This research is an attempt to inform the scientific community on the potential of augmented scour attributable to flow concentration that is due to the lateral spacing of structures and to compare it with nonconcentrated flow-induced scour. The authors employed the FLOW-3D numerical model for this study. This model was first calibrated using a physical model experiment performed in the dam break flume of the University of Ottawa, Canada. Results from this study demonstrate that flow concentration due to the lateral spacing of structures leads to greater scouring than for the case of an isolated structure and that the magnitude of the scour, for most cases studied, was larger than what is prescribed by the latest building codes. [ABSTRACT FROM AUTHOR]

Xiao, Y.; Jia, H.; Guan, D.; Liang, D.; Yuan, S., and Tang, H., 2021. Modeling clear-water scour around the high-rise structure foundations (HRSF) of offshore wind farms. Journal of Coastal Research, 37(4), 749–760. Coconut Creek (Florida), ISSN 0749-0208. The high-rise structure foundation (HRSF) has been used in building the Donghai offshore wind farm in Shanghai, China. So far, few published studies can be found on the local scour around an HRSF. This study presents the results of a physical modeling investigation of the clear-water scour around two typical HRSF models consisting of eight piles and 10 piles, respectively. In the study, the flume bed was covered with uniform noncohesive sediment and the incoming flow was steady. The effects of the alignment angle of the HRSF, water depth, and relative sediment size on the equilibrium scour depth were analyzed. Results showed that the maximum scour depth always occurred around the middle piles on the shoulders of the HRSF. The alignment angle of the HRSF had little influence on the final equilibrium scour depth. For permeable multipile foundations, the scour depth increased when the water depth increased within the range of the testing conditions, which indicates a similar trend between a multipile foundation and a monopile. An empirical formula is proposed for estimating the equilibrium scour depth. [ABSTRACT FROM AUTHOR]

Black, K.P.; Kulkarni, K.B.; Naik, G.B.; Naik, M., and Mathew, J., 2021. Improving training wall orientation at river and estuary entrances. Journal of Coastal Research, 37(3), 484–493. Coconut Creek (Florida), ISSN 0749-0208. Natural river and estuary entrances adjust in response to the prevailing sedimentary and hydrodynamic environment. In India, during the monsoon rains, the ebb jet can be very large, firing water and sediments along a variable orientation to create the associated ebb deltas. However, once the entrance is trained onto a fixed alignment, this powerful jet "pump" can have adverse impacts. Due to downdrift erosion caused by the entrance training walls at the Old Mangalore Port (Karnataka, west coast of India), the breakwater was modified to reorient the ebb jet in the direction of the longshore drift. The goal was to beneficially use the natural pumping action to drive sand across the entrance without mechanical assistance. Three years of monitoring revealed improvements in downdrift beaches and navigational safety, while maintenance dredging has ceased. The entrance region has deepened by 854,166 m3 after reorienting the ebb jet over the period from October 2017 to February 2020. In contrast, the entrance shoaled by 160,305 m3 over the period from September 2008 to October 2017. The results are relevant to river and estuary entrances with moderate to strong river flows and/or tidal prism. [ABSTRACT FROM AUTHOR]

Rodil, I.F.; Long, Z.T.; Fegley, S.R.; Rodriguez, A.B., and Peterson, C.H., 2021. Benthic community responses to the filling of a hurricane-induced barrier island inlet. Journal of Coastal Research, 37(3), 601–610. Coconut Creek (Florida), ISSN 0749-0208. In September 2003, Hurricane Isabel created a new tidal inlet through Hatteras Island, a barrier island of North Carolina (U.S.A.). Within two months, the breach was filled with sand dredged from nearby areas. Subsequent ecological response of the benthic macroinvertebrate communities to the filling differed on shores on opposite sides of the island. Thus, the filled area on the high-energy sandy beach exhibited convergence in community composition and abundance with a nearby reference area within 30 months, whereas the filled area on the lower-energy sound shoreline still possessed a depauperate benthos. The high volume of long-shore sediment transport documented along the ocean beaches of Hatteras Island probably acted quickly to transport benthic macrofauna to the fill along with natural beach sediments, and thereby activating a rapid ecological response of the beach community. The beach community was dominated by annual macroinvertebrate species, which could account for mixing from nearby areas in the rapid macrofauna community response. In contrast, the Pamlico Sound shoreline experiences only local wind-driven waves and modest long-shore currents likely insufficient to import macrobenthos readily. Infrequent passive transport of macrobenthos and persistence of defaunated sediment habitats nearby probably slowed the macrofauna community response on the sound-shore side. Management intervention through habitat restoration would be recommended in the less dynamic sound shore environment compared to the high-energy ocean beach where ecological responses of the invertebrate community occurred rapidly. [ABSTRACT FROM AUTHOR]

DaSilva, M.; Miot da Silva, G.; Hesp, P.A.; Bruce, D.; Keane, R., and Moore, C., 2021. Assessing shoreline change using historical aerial and RapidEye satellite imagery (Cape Jaffa, South Australia). Journal of Coastal Research, 37(3), 468–483. Coconut Creek (Florida), ISSN 0749-0208. The coastal zone is a dynamic area which can experience substantial natural change in short time periods, but changes are also associated with human modifications to the coastline. This case study is focused around assessing shoreline change associated with the Cape Jaffa Marina and canal estate in South Australia. The research comprises a GIS based analysis of shoreline change utilising aerial imagery from 1975 to 2005, which provides information of the morphological coastal trends prior to construction in 2008 of the marina/canal estate. In addition, imagery collected by the RapidEye satellite constellation was used to assess shoreline changes in the decade since construction, 2009 to 2019. The shoreline change statistics over the past few decades were calculated using the Digital Shoreline Analysis System extension of ESRI's ArcGIS. The image analysis workflow is based on the objective extraction of shoreline proxies from individual image statistics in a semi-automated process and is used to identify the waterline and edge of vegetation shoreline proxies in a time series analysis. The results provide a case study of a historically progradational sandy coastline experiencing substantial amounts of alongshore sediment transport, the corresponding obstruction from coastal infrastructure, and the resulting morphological changes to the Cape Jaffa shoreline. Shoreline change trends were altered from a predominantly accretional shoreline before the construction of the marina to one oscillating between extremes of erosion and accretion. The results showed significant accretion occurring updrift (Net Shore Movement (NSM) of 106 m) and significant erosion downdrift (NSM of –80 m) of the marina's training walls and entrance. The information derived from Earth observation satellites, such as RapidEye, can provide valuable insights into trend analysis due to their relatively high spatial (5 metre) and temporal resolution (5.5-day revisit). [ABSTRACT FROM AUTHOR]

Castagno, K.A.; Donnelly, J.P., and Woodruff, J.D., 2021. Grain-size analysis of hurricane-induced event beds in a New England salt marsh, Massachusetts, USA. Journal of Coastal Research, 37(2), 326–335. Coconut Creek (Florida), ISSN 0749-0208. Tropical cyclones pose a growing threat to coastal infrastructure and livelihood. Because instrumental and historic records are too short to help us understand interactions between tropical cyclones and climate on a longer scale, proxy records are the only means for reconstructing millennia of tropical cyclone impacts. This study determines grain-size trends in storm-induced overwash deposits along a transect of sediment cores from a salt marsh in Mattapoisett, Massachusetts, to characterize sorting trends and compare deposits associated with individual storms. The overwash deposits preserved within the high-marsh peat provide a record spanning the last two millennia. Building on a 2010 study, a different approach was used to accurately determine the grain-size distribution of overwash deposits from cores in a transect running perpendicular to the adjacent sandy/gravely barrier. Although maximum grain-size values are expected to decrease as distance from the barrier increases, not all event deposits that were studied follow this trend within uncertainty. Analysis of the storm event beds reveal a significant difference in settling trends between historic and prehistoric deposits, with historic deposits largely displaying landward-fining trends and prehistoric deposits largely displaying landward-coarsening trends. This suggests changes in the hydrodynamic or that geomorphic regime may have altered the way in which storm beds were deposited at this site. This new in-depth, transect-based approach has utility for improving the accuracy of future storm reconstructions, particularly for events for which no historic record exists. [ABSTRACT FROM AUTHOR]

Jo, Y.J. and Cho, Y.J., 2023. How the beach restoration process, driven by bound mode infra-gravity waves underlying swells in a mild sea, is affected by the presence of LCB: A numerical study. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 618-622. Charlotte (North Carolina), ISSN 0749-0208. This study aims to numerically investigate the impact of Low Crested Breakwater [LCB] on the beach restoration process driven by bound mode infra-gravity waves beneath swells in a mild sea. In doing so, the authors also delve into the evolving extent of boundedness of infra-gravity waves to a wave packet during shoaling. Additionally, the authors explore the effects of this evolution on sediment transport. The infra-gravity waves were extracted from a numerically simulated wave field using the Empirical Mode Decomposition method. Numerical results reveal a transition in the cross-correlation between a wave packet and infra-gravity waves from negative to positive during shoaling, especially when the phase of infra-gravity waves is initially shifted by as much as π. These correlation patterns align well with the wave data acquired by Abdelrahman and Thornton. Furthermore, the degree of boundedness of infra-gravity waves to a wave packet has a significant impact on the sediment transport rate. When fully phase-locked, a substantial amount of sand, in the form of bedload, escapes offshore through the open inlet between LCB. Approximately 5 × 10–3m3/m of sand exits the inner zone of LCB per unit amplitude modulation period of a wave packet. Conversely, with a phase shift of π, the primary sediment transport mode at the open inlet between LCB becomes bedload. Sand migrating toward the shore balances with offshore-directed sediment transport, marking a departure from previous studies focused on monochromatic waves only. [ABSTRACT FROM AUTHOR]

Fitria, J.; Gemilang, R.I.A.; Purnama, B., and Prasetyo, A., 2023. Rapid changes in the coastal morphology of Amurang, North Sulawesi, Indonesia. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 289-293. Charlotte (North Carolina), ISSN 0749-0208. Changes in coastal morphology can occur through long-term processes, such as sediment transport, and through short-term processes, such as those caused by earthquakes, storms, or tsunamis. On June 15th, 2022, a rapid change in coastal morphology due to a landslide happened in the coastal area of Amurang, North Sulawesi, Indonesia. Morphological changes and their triggers were analyzed through a comparison of post-slide and preslide bathymetry data, satellite imagery, and analysis of the soil layers. Based on the comparison of bathymetry data, the maximum change in seabed depth in the landslide area was 51 meters with a curvature shape on the rupture surface. The coastline has retreated about 150 meters inland with around 2.34 million m3 of material displaced. The results show that the landslides on the Amurang Coast that caused the rapid morphological change in the area were not triggered by hydro-oceanographical conditions, tectonic events, or volcanic events. They were triggered principally by the over-steepened slope and the ground soil's ability to support the additional weight of building embankments over a thick sediment layer. [ABSTRACT FROM AUTHOR]

Muin, M. and Muslim, A.B., 2023. Anak Krakatau Landslide Tsunami and sediment transport simulation using non-orthogonal boundary fitted technique in spherical coordinate model. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 146-150. Charlotte (North Carolina), ISSN 0749-0208. This paper presents a simulation of a tsunami induced by the Anak Krakatau Landslide in Indonesia and the sediment dispersion transported by the tsunami. The hydrodynamic model of this simulation used a non-orthogonal curvilinear technique in Spherical Coordinates and was developed in GIS on Windows System, named MuTsunami. The advantages of MuTsunami are rapid computation, accurately solving complex geometry, and integrating with the sediment transport model. This software is suitable for an early warning system. MuTsunami has also been applied in the 2010 Mentawai and 2004 Aceh Tsunami. The results show good agreement with the observation data. The simulation results indicate that the tsunami reached Serang, Ciwandan, Kota-Angung, and Panjang within 1860, 2760, 2100, and 4140 seconds after the Anak Krakatau Landslide occurred. The waves along the coast occurred up to 9 m and 8 m for Banten and Lampung coasts. The sediment transport result shows bathymetric changes along the Banten coast 30 minutes after the landslide. The required time to simulate the tsunami from the Anak Krakatau Landslide is only 15 seconds which is suitable for an early warning system. [ABSTRACT FROM AUTHOR]

Hwang, B.-H.; Do, K.-D., and Chang, S.-Y., 2023. Morphological response of Storm Hinnamnor at Songjeong Beach using UAV-derived data. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 126-130. Charlotte (North Carolina), ISSN 0749-0208. This study investigated the morphological response of a wave-dominated beach to large storms via field data collection. The field data were collected on Songjeong beach facing SE in the south-eastern corner of Korea. This study measured pre- and post-storm beach volumes by Storm Hinnamnor using Unmanned Aerial Vehicle (UAV). In this storm event, the peak of the significant wave was 10 m, and the wave period mainly varied between 10.9s under stormy conditions. The incident waves were mostly easterly at 90-115.5°. During this event, due to the strong storm intensity, the upper part of the sediment showed significant erosion along the entire beach, and net accumulation took place in the revetment area by overwash. The highest substantial loss occurred in the SW section of the study area, associated with the wave direction. Compared to the SW section, the mid and NE section of the study area eroded sediment. It was transported to the upper beach near the revetment area, suggesting that the onshore sediment transported was dominated in this area. After the storm, the local government undertook beach nourishment to restore the deposition sand on the revetment to the beach. This study carried out the UAV survey after beach nourishment and estimated the sediment volume by overwash. As a result, it was estimated that the amount of sand transported to the offshore area was 9533 m3, and the overwash deposition volume was 1441.3 m3. This study shows that UAV surveys can effectively estimate the morphological response of storm on the beach. [ABSTRACT FROM AUTHOR]

April Le Quéré, P.; Nistor, I., and Mohammadian, A., 2020. Numerical modeling of tsunami-induced scouring around a square column: Performance assessment of FLOW-3D and Delft3D. Journal of Coastal Research, 36(6), 1278–1291. Coconut Creek (Florida), ISSN 0749-0208. In recent years, tsunamis have caused considerable damage to coastal infrastructures and inflicted numerous casualties in coastal communities in the impacted regions. The information, which the design requirements for tsunami-resistant infrastructures is based on, is still in its preliminary stages. The focus of the study was to investigate, by means of a numerical model, the scouring occurring around a single, square column subjected to tsunami floods. A three-dimensional (3D) hydrostatic numerical model (Delft3D) and a 3D nonhydrostatic model (FLOW-3D) were used to replicate a series of physical tests conducted at the University of Ottawa, which consisted of a dam-break wave impacting onto a single square column installed over a movable sediment bed. These experimental tests were conducted in the Dambreak Flume at the University of Ottawa. Four different turbulence models and two different sediment-transport models were tested to find the most appropriate combination, which could model the complex flow characteristics associated with a dam-break–type bore. An extensive review of the hydrodynamic and scouring performance of various numerical models was also included in this study. [ABSTRACT FROM AUTHOR]

Hu, P.; Tan, L., and He, Z., 2020. Numerical investigation on the adaptation of dam-break flow-induced bed load transport to the capacity regime over a sloping bed. Journal of Coastal Research, 36(6), 1237–1246. Coconut Creek (Florida), ISSN 0749-0208. Knowledge about dam-break flow-induced bed load transport over a sloping bed is widely used to shed light on swash-induced bed load transport over erodible beaches. However, numerical modeling of flows in this configuration has mostly assumed instant sediment adaptation and accordingly ignored the potential lag between bed load and its capacity regime. This paper presents a numerical assessment of the bed load adaptation characteristics in this configuration. Two models are considered: a capacity model that assumes negligible lag and a noncapacity model that uses a sediment adaptation empirical relationship to appreciate the lag. Two experimental dam-break flow events over a fine sand (1.3 mm) bed and a coarse gravel (8.4 mm) bed are numerically simulated. Three estimates are used for the bed friction, five empirical relationships are used for the sediment transport rate at capacity, and five empirical relationships are used for the adaptation length. The following findings are obtained. First, bed friction values calibrated by hydrodynamics do not necessarily represent actual bed resistance better than existing empirical bed friction relationships. Second, given a reasonably well-estimated adaptation length, the noncapacity model can give comparable or better predictions of the sediment transport rate for both fine and coarse sediments, whereas the performance of the capacity model strongly depends on sediment adaptation features. [ABSTRACT FROM AUTHOR]

Beck, T.M.; Wang, P.; Li, H., and Wu, W., 2020. Sediment bypassing pathways between tidal inlets and adjacent beaches. Journal of Coastal Research, 36(5), 897–914. Coconut Creek (Florida), ISSN 0749-0208. This study investigated the sediment transport pathways in three sandy barrier, tidal inlet systems through sediment tracking within a numerical model that simulates hydrodynamics and morphodynamics. The three tidal inlet systems, Coos Bay, Oregon, Shark River Inlet, New Jersey, and John's Pass, Florida, represented high-, medium-, and low-wave energy regimes for U.S. inlets (Pacific, Atlantic, and Gulf of Mexico Coasts, respectively). Three methods employed to define sediment pathways from the results of a numerical morphology model were evaluated: (1) morphodynamic interpretation, (2) mean transport vectors across the modeled inlet, and (3) sediment tracer migration. The sediment tracing methodology employed in this study allowed for an evaluation of the sediment transport pathways between the various morphologic features of a tidal inlet, as well as their respective processes that drive the exchange of sediments. Characterizing and correlating the dominant and subdominant, or seasonal, sediment pathways between tidal inlet morphologic features (sediment reservoirs) can improve long-term models of an inlet sediment system. Divergences in pathways to subfeature shoals of a complex tidal inlet shoal, such as the updrift and downdrift shoals of an ebb-tidal delta, can be resolved through tracking sediment migration. The results of this study illustrate the value of including sediment-tracking techniques in simulating sediment bypassing and the potential of this application to inform coastal engineering and design modifications to the sediment reservoirs of tidal inlet systems. [ABSTRACT FROM AUTHOR]

Carbajal, N.; Montaño-Ley, Y.; Páez-Osuna, F.; Soto-Jiménez, M., and Tuxpan, J., 2020. Numerical investigation of sea-bottom morphological changes by the interaction of tidal flow and idealized coastal geometries. Journal of Coastal Research, 36(5), 981–991. Coconut Creek (Florida), ISSN 0749-0208. Different idealized geometries, resembling shallow tidal-dominated seas with different geographical features like bays, islands, and headlands, were investigated by applying a two-dimensional hydrodynamic-numerical and morphological model. The geometries were exposed to fast oscillatory tidal velocities and unbounded sediment availability. The interaction between the oscillatory tidal flow and the seabed, in all the experiments, generated vorticity and small bed perturbations that evolved to incipient shoals or bed forms. The reversing tidal regime created asymmetric sediment transport, which in turn triggered sediment accretion at specific areas. The flow, residual circulation, and vorticity produced by mixed tides, and, in the presence of coastal morphological features like headlands, bays, and islands, also triggered the generation as well as the enhancement of asymmetric shoals. Experiments applying only one tidal component revealed a more symmetric pattern of vorticity and sediment accretion. Satellite images of areas of the Gulf of California including an island, bay, and headland were compared with the predicted tidal morphodynamics. They reflected quite well, in all cases, accretion areas located in sites similar to those predicted in the present numerical investigation. [ABSTRACT FROM AUTHOR]

Black, K.P.; Reddy, K.S.K.; Kulkarni, K.B.; Naik, G.B.; Shreekantha, P., and Mathew, J., 2020. Salient evolution and coastal protection effectiveness of two large artificial reefs. Journal of Coastal Research, 36(4), 709–719. Coconut Creek (Florida), ISSN 0749-0208. Two offshore reefs constructed at Ullal, Karnataka, on India's west coast, are exhibiting coastal protection benefits. The reefs are large (275 m and 325 m long) and uniquely placed well offshore (600 m and 760 m) in intermediate depths (6 and 7 m below chart datum). Their crests are between low-tide and midtide level. Bathymetric and beach surveys show that sand has accumulated to form two evolving shoreline salients, which are currently 2–3 times the length of the reefs. The salients have grown underwater on the inner shelf to create a large sand-retention zone up to 1 m thick and stretching from the beach to the distant lee of the reefs. The reefs are the first protection structures that have restored the beaches and enhanced sand storage over this broad, severely eroded region, both inshore and on the inner shelf. Prior rubble-mound rock revetments (seawalls) and 50–70-m-long groynes failed to restore the beach in stormy monsoon conditions, while the inner shelf continued to erode. The reefs were designed using a combination of computer simulations, measurements of natural salients in India, and empirical relationships. The methodology that led to the reef shapes/sizes and their position offshore is discussed, along with monitoring results. [ABSTRACT FROM AUTHOR]

Briggs, T.R.; Figlus, J.; Torres-Freyermuth, A.; Puleo, J.A.; Warren, W., and Alrushaid, T., 2020. Variability in onshore sediment transport on a natural beach during a Central American cold surge event. Journal of Coastal Research, 36(3), 487–497. Coconut Creek (Florida), ISSN 0749-0208. Beaches facing the Gulf of Mexico along the northern part of the Yucatan Peninsula experience frequent Central American cold surge events, or northerly storms locally called "Nortes," which interrupt the usual daily patterns of sea- and land-breeze–dominated nearshore dynamics. These perturbations of prevailing hydrodynamic forcing conditions also affect sediment distribution and transport parameters in the surf and swash zone, which are critical elements in understanding and modeling complex morphodynamic processes during storm events. However, detailed measurements of sediment characteristics throughout the water column during a storm event are scarce. This study presents field measurements of bottom and suspended sediment transported in the onshore direction during a 24-hour storm event impacting the Yucatan Peninsula. Sediment load data within the water column collected in 3 hour intervals via vertical arrays of streamer traps, deployed at two cross-shore locations in the inner surf zone, are compared with sediment data from collocated bottom grab samples. Time series of grain size distributions, sediment statistics, and respective vertical variations throughout the water column are related to measured bed-level changes to verify applicability of simple erosion and accretion predictors. Results indicate that bottom sediment and sediment distributions throughout the water column deviate substantially due to storms, highlighting the complexity and difficulty of assessing sediment transport and morphodynamic processes with a single-parameter sediment characteristic. Calculated total onshore transport rates during the Norte were on average one order of magnitude higher than during nonstorm conditions. [ABSTRACT FROM AUTHOR]

Zhang, J.; Larson, M., and Ge, Z.P., 2020. Numerical model of beach profile evolution in the nearshore. Journal of Coastal Research, 36(3), 506–520. Coconut Creek (Florida), ISSN 0749-0208. A numerical model was developed to simulate hydrodynamics (waves, currents, and mean water level), cross-shore sediment transport, and beach profile evolution in the nearshore assuming negligible longshore transport gradients. Particular focus was put on describing the response of the subaerial region of the profile, including the foreshore and the berm, as well as the exchange of material between the swash and the surf zone. The model consists of different modules describing wave transformation, cross-shore currents, mean water elevation, and cross-shore sediment transport. For the purpose of model calibration and validation, detailed, high-quality data on hydrodynamics and beach profile response from the SUPERTANK data collection project were employed. The experimental cases studied encompassed several types of profile evolution, including berm erosion and bar formation, berm flooding and erosion, and offshore mound evolution for a narrow- and broad-crested mound. Overall, good agreement was obtained between calculations and measurements, especially for the foreshore and the berm, whereas the calculated bar shape was smoother than the measured shape. The model produced robust and reliable predictions of cross-shore transport and profile evolution for the cases investigated. Subsequent work in model development will involve dune erosion and overwash as well as validation toward field data. [ABSTRACT FROM AUTHOR]

Mengual, B.; Bertin, X., and Martins, K., 2020. Importance of wave non-linearity for 3D morphodynamic modelling. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1201-1205. Coconut Creek (Florida), ISSN 0749-0208. The effect of wave non-linearity on morphological changes of a sandbar is investigated through a realistic application at Duck Beach (North Carolina, USA) of a 3D state-of-the-art process-based morphodynamic model, which couples sediment transport, currents and waves (vortex force formalism). From simplified 1D/2DH models, previous studies highlighted that acceleration skewness of non-breaking waves over a sandbar could promote its progressive onshore migration. This process can counterbalance the offshore migration occurring under breaking waves through the development of strong offshore-directed "undertow" currents near the seabed. Based on the existing literature, an additional bedload flux associated to acceleration skewness of waves is implemented in the 3D model. Numerical experiments with and without this additional term clearly demonstrate the need to account for this supplementary wave-induced transport to reproduce onshore migration phases of the sandbar. Effectively, even a model integrating wave asymmetry effects on bedload flux estimates and 3D wave-current interactions fails to reproduce the observed onshore migration of the sandbar. [ABSTRACT FROM AUTHOR]

Do, J.D.; Chang, Y.S.; Kim, C.H.; Kim, W-.H.; Lee, B-.G.; Wie, G. J., and Jin, J.-W., 2020. Measurement of nearshore seabed bathymetry using airborne/mobile LiDAR and multibeam sonar at Hujeong Beach, Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1067-1071. Coconut Creek (Florida), ISSN 0749-0208. Accurate bathymetric measurements are important, especially in nearshore areas, because coastal sediment transport and the resulting beach erosion/accretion processes are significantly affected by seabed topography. At Hujeong Beach in Korea, for example, local shorelines show severe spatiotemporal variations as a result of seabed topography including underwater rocks. The accuracy of bathymetry measurements are not guaranteed, however, because high-accuracy acoustic sensors—such as multi-beam echo sounders—have a limited measurement capability. In this study, we investigated the accuracy of the nearshore bathymetry at Hujeong Beach using airborne LiDAR (a-LiDAR) data from May, 2017. One of the benefits of a-LiDAR is its ability to conduct both onshore and offshore mapping by detecting laser pulses reflected from land, the sea surface, and seabeds. The a-LiDAR measurements were validated onshore in a sloped roadside area using data measured via ship-mounted mobile LiDAR (m-LiDAR). A high agreement was found between the two datasets, with R-squared values of 0.9999 and mean square errors less than 0.05 m2. In measurements of seabed bathymetry, a-LiDAR agreed well with measurements from a multi-beam echo sounder over a sandy seabed and showed an accuracy similar to the m-LiDAR validation results. However, the accuracy of a-LiDAR measurements decreased significantly over rocky seabed; the mean square error compared to the multi-beam data increased to 0.6–0.8 m2. The high a-LiDAR errors over this rocky area may be a consequence of the irregular shape of its surface. Return signals from underwater rocks of varying shapes may be spread over wider angles, causing signal interference and reducing the measurement resolution in the area. [ABSTRACT FROM AUTHOR]

Cao, Z.; Zhang, C.; Chi, S.; Zhuang, L., and Zheng, J., 2020. Video-based monitoring of an artificial beach nourishment project. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1037-1041. Coconut Creek (Florida), ISSN 0749-0208. This paper presents a case study on field observation of a new artificial beach nourishment project in Rizhao Coast, China. Using video-based monitoring technique combined with beach profile surveying, wave overtopping features prior to nourishment, shoreline change during the construction, and short-term post-fill morphological evolution of the artificial beach are observed and analyzed. Results show that wave overtopping characteristics and nourishing process can be quantified through video imagery analysis. Two-month post-fill profile and shoreline data reveal that little sand has been moved to the deep water and overall sand volume above -6 m elevation remained stable. The northern beach evolution was dominated by alongshore sediment transport and the eroded sands from central beach were mainly transported to the north, while the southern beach evolution was affected by both alongshore and cross-shore processes due to sheltering effect of the southern breakwater. Attention is recommended to be paid to the relationship between overwash-driven onshore sediment transport and berm/backshore evolution, as well as the future evolution of beach morphology close to the northern breakwater. The present study suggests that integrating the video-based and the conventional monitoring approaches can be helpful to capture and interpret in more details the physical processes involved in different phases of a beach nourishment project. [ABSTRACT FROM AUTHOR]

Bertin, X.; Mengual, B.; de Bakker, A.; Guérin, T.; Martins, K.; Pezerat, M., and Lavaud, L., 2020. Recent advances in tidal inlet morphodynamics modelling. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1016–1020. Coconut Creek (Florida), ISSN 0749-0208. Tidal inlets connect the ocean to inner water bodies and are present worldwide. Complex interactions between tides, waves and shallow bathymetry often drive fast morphological changes but the underlying processes remain only partly understood. To better understand these processes, the development and application of morphodynamic models represents a unique perspective. This paper evaluates the impact of recent developments in the modelling system SCHISM, which include: a WENO method to solve the Exner Equation, a 3D coupling between waves and currents using a vortex force formalism, an adaptive parameterization for the dissipation of short waves by breaking and improved representations for wave-induced sediment transport. In order to evaluate the relevance of these developments, SCHISM is applied to the Maumusson Inlet, a mixed-energy inlet located on the Western Coast of France. Model-data comparison reveals firstly that complex wave-current interactions take place over the inlet ebb-delta, that include partial wave blocking during the ebb. Compared to classical 2DH approaches, our improved modelling system better reproduces the dynamics of adjacent beaches, inlet migration under oblique waves and sediment infilling of the main channel under storm waves. The relevance of these developments is demonstrated at the mixed-energy Maumusson Inlet (France). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The Modaomen Estuary has evolved from a runoff-dominated to runoff-and-wave-dominated estuary; thus, waves have become an important dynamic force. However, the nearshore irregular waves and wave-induced currents in the Modaomen Estuary have not been well studied. For the first time, a coupled wave-current model was developed in which the wave properties were calculated by the hyperbolic mild-slope equation, and the flow motion was simulated using a depth-averaged shallow water equation that was modified by introducing wave radiation stresses. The computational capability of this model was well calibrated by laboratory data from published references. Subsequently, the validated model was employed to analyze the wave height distributions, flow field characteristics and residual current under irregular waves, as well as to determine the differences in the above results with the scenarios under pure wave or pure tide. The results showed that the irregular wave heights reach 0.75 m near the sand bar and its surrounding shoals, reach 0.7 m in the main channel, and are approximately 0.3 m in the wave shadow area behind the Sisha shoal, which is more powerful than that under regular waves. The effect of waves on the current at the maximum ebb tide is greater than that at the maximum flood tide, especially in the estuarine shoal zone. Compared with the current velocity under pure tide, the residual current velocity is larger, and the vortex scale and the sediment transport route are all prominent under the combined wave and tide. [ABSTRACT FROM AUTHOR]

Fang, K.; Wang, H.; Sun, J.; Zhang, J., and Liu, Z., 2020. Including wave diffraction in XBeach: Model extension and validation. Journal of Coastal Research, 36(1), 116–127. Coconut Creek (Florida), ISSN 0749-0208. An extended version of the XBeach model is presented in this paper to improve the accuracy of predicted wave and current fields and sandy beach evolution in scenarios in which wave diffraction takes effect. Following the approach successfully implemented in the Simulating Waves Nearshore (SWAN) spectral wave model, a diffraction parameter is introduced into the wave action balance equation in XBeach to take wave diffraction into account. An alternative wave breaking index and the formulation for the critical velocity are also tested in the extended model to achieve better model–data agreement. The extended model is validated by comparing the simulation results with those of physical tests for fixed and movable sea beds. The computed wave height, wave-induced current field, and beach evolution are found to be in satisfactory agreement with the measurements, and the numerical modeling capacity of the extended model to represent wave diffraction effect is thus demonstrated. [ABSTRACT FROM AUTHOR]

Nguyen, T.H.T.; Park, S.W., and Ahn, J., 2020. Numerical method to determine upstream scour slope in relation to turbulence and particle movement. Journal of Coastal Research, 36(1), 189–195. Coconut Creek (Florida), ISSN 0749-0208. Several studies have been conducted to investigate the behavior of scour hole, which happens naturally at the end of the bed protections in the streams and rivers, because this phenomenon can result in the instability or destruction of man-made structures in the area. Some formulas or equations were introduced to calculate the upstream scour slope, one of the most important scour properties, but the application shows some difficulty because of the lack of data. This paper presents a simple but reasonable method to find upstream scour slope with the employing of a numerical simulation, in particular by considering the relationship between turbulence and particle movement. [ABSTRACT FROM AUTHOR]

Coastlines are vulnerable to the effects of climate change and sea-level rise as well as modifications in the wave climate and, in particular, increased storminess. The coastal areas of islands form part of this scenario and the Martinique shoreline illustrates this intensification of shoreline retreat and coastal erosion. In the context of this critical situation, a coastal observation network was set up in 2010 to monitor the evolution of the coast of Martinique. This network includes 28 beaches along the coast of Martinique and is based on studies of shoreline evolution using aerial photographs and topographic surveys of 71 cross-shore transects. The main aim of this network is to characterize the modal and seasonal dynamics of these vulnerable beaches and to estimate their resilience capacity and trends in the context of the increasing frequency of hurricanes. Analysis of the measurements over the last ten years highlights a general acceleration of the shoreline retreat. Furthermore, in terms of seasonal coastal evolution processes, the results clearly show the weak effect of the longshore sediment transport component on the open beaches of Martinique Island. However, a predominant cross-shore sediment transport component is observed on smaler bay beaches, which represent the most numerous beach type on the island (including several pocket beaches). On the short-term scale, the results of hydrodynamic and morphodynamic measurements highlight variable and intensive beach dynamic responses with a determining role played by shoreface parameters and coral-lagoon complexes. While cyclones have a significant impact on reducing the slope of beach profiles, our measurements reveal a significant resilience of eroded beaches owing to constructive swell. We also demonstrate that the hurricane season is not the season with the strongest morphosedimentary impacts. This almost ten-year-old observation network, provides an overview of shoreline evolution on Martinique and is an efficient management tool for the Lesser Antilles coastal environments. [ABSTRACT FROM AUTHOR]

Sediment mobilization, especially from offshore bay to the coast during the Holocene, along the inner continental shelf of Bay of Biscay is less understood. Acoustic and sediment sampling and surveys were conducted offshore of the Bay of Étel to define the shallow geologic framework and the sedimentology. Results of these campaigns are used to identify and map Holocene deposits, discuss sediment transport pathways and depth of closure using Hallermeier's approach in order to define the active sedimentary prism using the depth of closure on a meso-tidal and wave dominated coast. In the Bay of Étel, Holocene sediments are concentrated between rocky shoals and emerged rocks, passing from external zone by sand lobe, 20 m thick to the medium zone, 15 m thick, to the beaches of the Gâvres-Penthièvre beach dune system (modern coastal prism). This case study found that the thickest deposits of Quaternary sediments observed along the inner shelf have a strong dependence on coastal topography and structural heritage. The presence of offshore basement shoal has been determined to have exercised control over sediment transfers from offshore to landward regions during the last marine inundation. Due to the lack of any significant modern fluvial input of sand in the region, the Holocene deposits are inferred to have been derived by reworking of relict Pleistocene and older inner-shelf deposits. Sediment textural trends and seafloor morphology from the medium zone to the beach dune system indicate an absence of relationships (linking) between the modern sedimentary prism and the potential source of sediment to the shoreline. [ABSTRACT FROM AUTHOR]

Cheng, J. and Wang, P., 2019. Unusual beach changes induced by Hurricane Irma with a negative storm surge and poststorm recovery. Journal of Coastal Research, 35(6), 1185–1199. Coconut Creek (Florida), ISSN 0749-0208. The coast of west-central Florida, facing the Gulf of Mexico, experienced Hurricane Irma with a negative surge of 1.1 m and a highly oblique northerly approaching wave in September 2017. This unusual hydrodynamic condition provides an opportunity to investigate the effect of surge and incident wave direction on morphology changes. Beach profiles, spaced at 300 m apart, along a 15-km stretch of beach were surveyed 2 weeks prior to the passage of Hurricane Irma and 1 week after and continued for up to 5 months after the passage to obtain Irma-induced erosion as well as post-Irma recovery. Owing to the occurrence of negative surge, the profile volume of the dune field remained mostly stable. The majority of beach erosion occurred below mean sea level, with a considerable amount of sediment transported seaward of the depth of closure. This is opposite to the conservation of beach profile volume above depth of closure under several earlier storms with a positive surge. The alongshore variation of overall beach profile volume erosion demonstrates a southward decreasing trend, due to a southward decreasing wave height as controlled by the northerly incident wave. After the passage of Irma, minor beach volume recovery occurred during the calm period of the fall season. Opposite to the typical erosive beach in winter, the most substantial beach accretion and onshore bar movement were observed during the following peak winter season as beach/bar evolved toward equilibrium. The profile volume in the dry beach region experienced a complete recovery in the first 5 months after Hurricane Irma. Shoreline change is a valid proxy for beach volume change during both the erosive and the recovery phase of Irma. The systematically measured beach profiles provide a solid dataset to calibrate process-based models to study beach morphodynamics. [ABSTRACT FROM AUTHOR]

Gainza, J.; Garnier, R.; Nuñez, P.; Jaramillo, C.; González, E.M.; Medina, R.; Liria, P.; Epelde, I.; Uriarte, A., and Monge-Ganuzas, M., 2019. Accelerating beach recovery by plowing the intertidal bar: A field experiment along the northern Spanish coast. Journal of Coastal Research, 35(5), 973–984. Coconut Creek (Florida), ISSN 0749-0208. Subaerial beach width plays a vital role when it comes to protecting coastal settlements and communities from storms. In many beaches the accretionary sequence is often characterized by the onshore migration of one or several intertidal bars that can eventually weld to the shore and contribute to the increase of the dry (subaerial) beach surface. An innovative experiment was carried out in summer 2015 to accelerate the onshore movement of the intertidal bar at Laida beach, Basque Country, northern Spain, by plowing it mechanically. A control zone where the bar could evolve naturally and a test zone where the plowing was performed were both defined. The aim of this study is to assess the effect of plowing on intertidal bar migration by analyzing field data collected during the experiment. Hydrodynamic data were gathered during a 3-day field campaign. Additionally, six cross-shore transects were defined, and their topographic data were taken every 15 days. Furthermore, a video imaging system allowed following and recording the planform evolution of the beach. Analyzing each profile's topographic data, it was observed that the intertidal bar in the plowed zone moved farther onshore than the intertidal bar in the control zone, suggesting that the plowing accelerated the onshore migration of the bar. Sediment transport was calculated by feeding a sediment transport formula with the hydrodynamic measurements taken, and it was concluded that the natural onshore migration of the bar is driven by onshore transport gradients related to wave asymmetry and skewness. It is suggested that the plowing caused an increase of onshore sediment transport onto the intertidal bar. However, further study that includes other field experiments, physical modeling, or both is required to identify the processes involved. [ABSTRACT FROM AUTHOR]

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

Hallin, C.; Almström, B.; Larson, M., and Hanson, H., 2019. Longshore transport variability of beach face grain size: Implications for dune evolution. Journal of Coastal Research, 35(4), 751–764. Coconut Creek (Florida), ISSN 0749-0208. This study investigates grain-size sorting through longshore transport processes and how it influences dune evolution. The analysis is based on a data set of 58 sediment samples distributed alongshore over a 6.5-km-long sandy beach in Ängelholm, Sweden. Grain size differs significantly from north to south, where median grain size varies from about 0.4–0.15 mm. The long-term coastal evolution is derived from shoreline change analysis of a series of aerial photos from the 1940s until today and from longshore sediment transport rates calculated on the basis of wave data simulated by the SWAN wave model employed in the Coastal Engineering Research Center (CERC) formula. The results show an almost unidirectional longshore transport from north to south; the beach is eroding in the northern part and accreting in the southern part. The McLaren model, a grain size–based model to predict transport direction, was tested against the grain size data. The test indicated transport in the opposite direction. This result supports previous studies suggesting that the McLaren model has limited applicability for sandy beaches with a dominant longshore transport. The sediment samples were collected at the mid–beach face position in an area where sediment is supplied to the beach during accreting conditions. Sediment in the appropriate grain size to build dunes—at this beach, 0.2–0.3 mm—was found in the parts of the beach where the dunes are growing. In the eroding parts, the sediment was coarser, suggesting that the longshore transport influences the supply of sediment for aeolian transport. The gradients in longshore transport rate were also found to affect dune morphology; the dunes were higher in the eroding and stable parts of the beach and lower in the accreting parts. [ABSTRACT FROM AUTHOR]