Cialone, M.A. and Slusarczyk, G., 2020. Impact of inlet closures on surge response in New Jersey back bays. Journal of Coastal Research, 36(6), 1111–1120. Coconut Creek (Florida), ISSN 0749-0208.

The in-depth study presented in this paper includes numerical modeling and analysis of the effects of storm surge barriers (inlet closures) on water levels in the back bays of New Jersey during storm events. Eleven inlet closures were each numerically “closed” singularly and in combination with other inlet closures. Storm surge simulations were run with all 11 inlets “open” as a base condition and for each of the inlet singular closure and combination closure conditions. In this paper, four combinations of inlet barrier positions were selected to demonstrate the ability of surge barriers to potentially prevent surge propagation into the back bays of New Jersey, including: (1) the base condition (all inlets open); (2) closing one of the larger entrances, Barnegat Inlet; (3) all inlets closed except for a small inlet (Corson Inlet) and an extremely wide inlet entrance (Little Egg/Brigantine Inlet); and (4) all inlets closed. A comparison of maximum surge envelopes and water-level time series from simulations of 10 synthetic tropical storms with the inlets in these four configurations was made. Three of the largest bay systems, Barnegat Bay, Manahawkin Bay, and Little Egg Harbor, are the main focus of this paper. As expected, the greatest reduction in water level in the bays occurs when all inlets are closed with surge barriers. The average reduction in water level for the three bays mentioned above with all inlets closed is 0.70 m, with a maximum average reduction in Little Egg Harbor of 0.73 m. Simulations with only Barnegat Inlet closed show the greatest reduction in water level in the northern portion of Barnegat Bay, whereas surge can still propagate into the southern portion of the bay through Little Egg/Brigantine Inlet. However, storms with strong N-to-S wind can inhibit flow entering from the open inlet at Little Egg/Brigantine and therefore show the greatest reduction in maximum water level in the southern portion of Barnegat Bay for these conditions. With some inlets open and some closed, strong alongshore winds can also cause surge to become trapped behind adjacent inlet closures. This demonstrates the importance of considering multiple means of flow propagation into an embayment as well as the timing of implementing surge barriers to optimize surge protection.

Waghmare, S.M.; Hanamgond, P.T.; Mitra, D.; Koti, B.K., and Shinde, P.S., 2020. Application of remote sensing and GIS techniques to study sediment movement along Harwada Beach, Uttar Kannada, west coast of India. Journal of Coastal Research, 36(6), 1121–1129. Coconut Creek (Florida), ISSN 0749-0208.

Beaches, the most dynamic coastal landform on Earth, show dynamic changes over different timescales such as diurnal, tidal, monthly, and seasonal changes. These changes can be constructive or destructive. The long-term studies on beaches help in understanding and planning for any coastal management programs. The present study was undertaken on Harwada Beach located in Karwar of Uttara Kannada district, on the West Coast of India, mainly to understand the morphological changes, sediment movement, and depositional environment through bimonthly beach profiles at five stations. In the present study correlation of the field data along with the remote sensing data (Sentinel 2A multispectral sensor) was carried out to understand the long-term changes. This study shows that the beach has undergone dominant erosion and exhibits cyclic movement of the sediments within the study area. The seasonal and annual study undertaken on Harwada Beach showed that the central part of the study area is most stable during the 4-year observation, while rest of the beach shows erosion.

Zurbuchen, J.; Simms, A.R., and Huot, S., 2020. Episodic coastal progradation of the Oxnard Plain, Southern California, USA. Journal of Coastal Research, 36(6), 1130–1144. Coconut Creek (Florida), ISSN 0749-0208.

As droughts are projected to intensify over the next century, determining the coastal response is pivotal for hazard mitigation in the future. Ground-penetrating radar (GPR), in combination with radiocarbon and luminescence (optically stimulated luminescence [OSL]) dating methods, provides insight into the coastal response of the Oxnard Plain, Southern California, to past droughts and storms through the imaging of sedimentary stratigraphy. GPR profiles contain three radar facies and two surfaces. Two of the radar facies and the two surfaces reflect cut and fill as the beach accreted and eroded. The third GPR facies is interpreted as aeolian deposits. For the first time, beach cusps are recognized in shore-parallel profiles as concave-up surfaces. Progradation rates at the 150- to 200-year timescale along the coastal Oxnard Plain have remained relatively constant, prograding at rates between 0.3 to 1.4 m a^–1. However, on decadal timescales, progradation has been episodic through time, with episodes of progradation after large floods along the nearby Santa Clara River, whereas wave action during periods of nonprogradation associated with prolonged droughts have resulted in the erosion of up to 90 m of the shoreline, equivalent to 5 to 120 years of the sediment record. Erosional surfaces often used to reconstruct past storms and tsunamis are more likely to be preserved in locations marked by higher rates of progradation, such as closer to the Santa Clara River delta.

Wang, H.; Li, W.; Zuo, C.; Dong, J.; Li, C.; Xu, H.; Liu, Q., and Pan, S., 2020. Saltwater intrusion in the Pearl River estuary (China): Variation characteristics and cause analysis. Journal of Coastal Research, 36(6), 1145–1153. Coconut Creek (Florida), ISSN 0749-0208.

The characteristics and influence factors of saltwater intrusions in the Pearl River Estuary were analyzed with tide gauge observation data, sea-level rise impact investigation data, and discharge data. The results show that (1) Seasonal variations in saltwater intrusion in the Pearl River estuary are obvious. Intrusion usually begins in September–October and ends in March–April of the following year. More saltwater is present in January, February, and October, which all had more than 10 events in the last 10 years. The number of saltwater intrusions fluctuated during 2009–2018, with the highest number of 14 in 2010 and the lowest of 2 in 2015. The annual saltwater intrusion duration increased obviously during 2015–2018 and lasted 171 days in 2018. (2) The integrated influence factor of sea level and discharge is closely related to frequency and duration of saltwater occurrence, with correlation coefficients of 0.7 and 0.5, respectively (95% confidence). From January to March, the Pearl River is in the dry season, and the integrated influence factor of sea level and discharge is positive, corresponding to more saltwater intrusions. From April to August, the seasonal sea level is low and discharge is high, resulting in a negative integrated influence factor of sea level and discharge and nearly no saltwater intrusion. From September to December, the seasonal sea level is high and the discharge is low. The integrated influence factor of sea level and discharge is higher than 1, corresponding to the high occurrence of saltwater intrusions. (3) Astronomical high tides mostly occur during return tides. The combination of astronomical tides and storm surges aggravates saltwater intrusions and their influence. (4) Countermeasures, including saltwater monitoring and forecasting, river basin management, and water conservation, are suggested to effectively address saltwater intrusion.

Li, H.; Zhang, M.; Yuan, J.; Chen, X., and Yu, G., 2020. Assessment on water environmental capacity of coastal lowlands networked with rivers and lakes in the northern region of Jiaxing, China. Journal of Coastal Research, 36(6), 1154–1161. Coconut Creek (Florida), ISSN 0749-0208.

Networked rivers and lakes are widely distributed in coastal lowlands. The water quality in these regions is generally not good and endangers the ecosystem because pollutants accumulate easily. The northern region of Jiaxing, China, was chosen for the case study. This paper investigates the water environmental capacity of coastal lowlands networked with several rivers and lakes. Field measurements were conducted to collect hydrological, water quality, and statistical data in different periods. The study area was divided into river and lake control units, with 10 units in total. The water environment capacity and pollution sources of each control unit were analyzed. The results showed that the pollution load and remnant water environmental capacity of each control unit differ significantly for different periods and control units. The total nitrogen (TN) and total phosphorus (TP) in the region were severely over the standard values. The chemical oxygen demand (COD) and TP in the river control units were higher than those in the lake control units. During the period between October 2018 and June 2019, all control units exceeded the water environmental capacity of TN, but most control units did not exceed the limit for COD. The remnant water environmental capacity of most control units follows the order that the dry period is greater than the normal period, which is greater than the flood period. Finally, according to the pollution sources and water environmental capacity of each control unit, specific measures to improve the water environment were proposed. This study provides references to assess and improve the water environmental capacity in coastal lowlands networked with rivers and lakes.

Lindner, B.L.; Holden, W.; Neuhauser, A., and Evsich, R., 2020. Climatology of tropical cyclone strikes along the southeastern coastline of the United States. Journal of Coastal Research, 36(6), 1162–1177. Coconut Creek (Florida), ISSN 0749-0208.

It has been theorized that tropical cyclones originating in or passing through the Gulf of Mexico (hereafter referred to as GOM tropical cyclones) may significantly impact communities along the Atlantic coast of the southeastern United States. To explore this hypothesis, site-specific climatologies were compiled using National Hurricane Center records of tropical cyclones that passed within 139 km of either Savannah, Georgia, or Wilmington, North Carolina, during the years 1851–2018. Return periods for tropical cyclones are longer for Savannah than for Wilmington, particularly for intense hurricanes. Intense GOM hurricanes are weakened by land interaction, which would result in longer return periods. A secondary maximum in the number of tropical storms early in hurricane season is more pronounced with proximity to the Gulf of Mexico, which is again consistent with the contribution from GOM tropical cyclones. Moreover, the percentage of tropical cyclones that passed near Savannah but did not make landfall is higher than that for Wilmington, again an indication of the significance of GOM tropical cyclones. Further evidence of the influence of GOM tropical cyclones is seen in the difference in approach angle and translational velocity between tropical storms and hurricanes. In addition, translational velocities for tropical cyclones increase with latitude, and translational velocities for tropical cyclones near either Savannah or Wilmington increase as the hurricane season progresses. Both relationships are likely due to the interaction of tropical cyclones with synoptic and planetary-scale winds. The median date for tropical cyclones has shifted earlier in recent decades for both Savannah and Wilmington, which is potentially an indication of climate change. An improved understanding of the climatology of tropical cyclones could lead to enhanced city planning, building codes, infrastructure, and resource management.

Ren, J.; Chen, B.; Li, Y.; Dai, J., and Men, L., 2020. Dynamic variation characteristics of the riparian zone temperature distribution under fluctuating water levels: Field experiments and numerical modeling. Journal of Coastal Research, 36(6), 1178–1196. Coconut Creek (Florida), ISSN 0749-0208.

Understanding the variations in water and heat transfer along the riparian zone under water-level fluctuations is essential for river water management, groundwater extraction, and ecosystem sustainability. The main purpose of this study is to describe the dynamics of the temperature field of the Dongting Lake beach under the fluctuation in the water level and to quantify its main influencing factors. Taking the section of Dongting Lake beach as the research object, an in situ monitoring device was used to monitor the water level, water temperature, and temperature at different depths of the beach in real time for 55 days, and the hydrothermal coupling model of the Dongting Lake beach was calibrated and verified. The main factors affecting the temperature field of the beach were determined by the global sensitivity analysis method. The results show that the fluctuation in the continental beach temperature field is small in the horizontal direction, the stratification phenomenon is obvious in the vertical direction, the temperature gradually rises with increasing depth, and the daily changes are weakened. During the high water level, the deep temperature of the beach has no obvious gradient change in the vertical direction, and as the water level of the river decreases, the external environmental temperature has a greater influence on the internal temperature field of the beach, resulting in a relatively pronounced gradient change in the deep temperature at the low water level. The results of the Morris one at a time global sensitivity analysis show that the permeability coefficient (K_s) has the greatest influence on the sensitivity of the model, followed by the porosity (n) and soil thermal conductivity (λ_s). The saturated moisture content (θ_s), residual moisture content (θ_r), and soil-specific heat capacity (C_s) have no significant effect on the model.

Xin, K.; Xie, Z.; Zhong, C.; Sheng, N.; Gao, C., and Xiao, X., 2020. Damage caused by Sphaeroma to mangrove forests in Hainan, Dongzhaigang, China. Journal of Coastal Research, 36(6), 1197–1203. Coconut Creek (Florida), ISSN 0749-0208.

Sphaeroma population expansion has become a serious threat to mangroves in China over recent years. This study investigated the distribution of Sphaeroma damaged forests in Hainan, Dongzhaigang, China, using RS data and field investigations. The damage to mangroves caused by Sphaeroma was categorized into three grades that were based on the death rate, damage rate, and recovery rate after a typhoon. The grades were seriously damaged forest, moderately damaged forest, and slightly damaged forest, and 8.18, 230.11, and 125.83 hm² were covered by the three grades, respectively. The most seriously damaged mangrove species were Bruguiera sexangula, Avicennia marina, and Bruguiera gymnorrhiza. However, many other mangrove species, such as Lumnitzera racemosa, Excoecaria agallocha, and Ceriops tagal, were nearly free from Sphaeroma. The integrated disaster index results, which were based on 59 different mangrove communities in the study area, showed that the communities mainly comprised B. sexangula and Bruguieras var. rhinochopetala, Sonneratia caseolaris, and Sonneratia apetala. The B. sexangula and B. gymnorrhiza and the Kandelia obovata communities were more seriously damaged than other communities. The distribution characteristics of the damaged mangroves indicated that communities that contained larger individuals and were closer to tidal creeks were more likely to be destroyed. Finally, the impacts of aquaculture sewage and duck farming may be driving Sphaeroma population expansion, and the results strongly suggested that dynamic monitoring of the Sphaeroma population after a typhoon should occur.

Souza Pereira de Ávila, A.; Leonhardt, A., and Diniz, D., 2020. Paleoenvironmental reconstruction off southern Brazil during a glacial period (66.5–47 kyr BP): Continental and oceanic environments. Journal of Coastal Research, 36(6), 1204–1214. Coconut Creek (Florida), ISSN 0749-0208.

Based on the palynological record of core REG 972, this work aimed to reconstruct the paleoclimatic and paleoenvironmental history from 66.5 to 47 kyr BP at the south Brazilian continental margin, as well as to identify the influence of continental discharge in the southern portion of the Rio Grande Cone. Nineteen samples were processed following the standard methodology for palynological studies. Organic matter (OM) content was measured in the sediments. The age model was established according to ¹⁸O isotopes analyses in benthic foraminiferal tests. The studied interval corresponds to a glacial interval, divided in palynozones (PZs): PZIa (66.5–64.5 kyr), PZIb (64.5–53.5 kyr), and PZII (53.5–47 kyr). PZIa was characterized by drier conditions, with grassland and salt marsh taxa dominance (Cyperaceae and Amaranthaceae). During PZIb and PZII, the increase of Bryophyta, Pteridophyta, Araucaria angustifolia, Arecaceae, and Alchornea triplinervia points to wetter and warmer conditions that may be related to the beginning of marine isotope stage 3 and later to the sea-level rise. In the oceanic environment, the presence of freshwater algae and marine indicators lead to the conclusion that marine conditions prevailed during Rio Grande Cone sedimentary formation, even under low sea-level conditions when terrigenous influence was stronger. The data on OM content, dinoflagellate taxa, and mean sea level changes point to a period of low productivity during PZI. In PZII, a period of higher productivity took place because of Subantarctic Shelf Water influence, bringing cold and nutrient-rich waters to the area.

Jaramillo, C.; Sánchez-García, E.; Jara, M.-S.; González, M., and Palomar-Vázquez, J.M., 2020. Subpixel satellite-derived shorelines as valuable data for equilibrium shoreline evolution models. Journal of Coastal Research, 36(6), 1215–1228. Coconut Creek (Florida), ISSN 0749-0208.

The analysis and prediction of shoreline variability are two of the main challenges in coastal engineering. Evaluating coastal behaviour in a target area usually requires access to long data series of high-resolution shoreline positions. Therefore, coastal engineers must have access to different data sources, such as topographic-bathymetric field campaigns, digital orthophotos, aerial photographs, video-camera monitoring systems, and satellite imagery. This last data source is the only one that has the great advantage of covering large areas of the world and including regular coverage of most coasts during all climates and seasons. However, mid-resolution satellite images have been neglected because the resolution available to the public is too coarse to provide information on most coastal morphodynamic changes. The aim of this study was to explore the applicability of mid-resolution satellite imagery with a subpixel acquisition method for the calibration and validation of equilibrium shoreline evolution models. The models' performance was assessed by means of a comparative analysis between shoreline-position data sets obtained from video-camera systems and satellite imagery at two beaches on the Mediterranean coast of Spain. Almost 4 months of shoreline measurements were considered for validation purposes of the models at Nova Icaria Beach, and more than 1.5 years of shoreline measurements were analyzed at Cala Millor Beach. The results show that the general erosion-accretion trend is adequately represented by the models compared to the shoreline measurements at a qualitative and quantitative level.

Fan, C.; Gui, F.; Wang, L., and Zhao, S., 2020. Evaluation of environmental quality based on remote sensing data in the coastal lands of eastern China. Journal of Coastal Research, 36(6), 1229–1236. Coconut Creek (Florida), ISSN 0749-0208.

Environment transformation is inevitable in the coastal lands of eastern China. It is a land characterized by rapid urbanization, which requires an objective method to evaluate environmental quality (EQ). In this study, a remote sensing–based theoretical research framework was used to create a synthetic remote sensing environmental index (RSEI). Then, spatio-temporal characteristics and transformation of EQ were evaluated by applying the RSEI to the coastal lands of Hangzhou Bay. Results demonstrated that: (1) the background value of the RSEI remained stable, but the standard deviation of the RSEI increased from 0.227 to 0.268 from 2000 to 2015; (2) the overall structure of EQ became polarized such that the two extreme grades (excellent and poor) increased by 13.000%; and (3) the lands where prominent EQ changes occurred were in Yinzhou (improvement) and Pinghu (degradation) in Hangzhou Bay.

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.

da Silveira, C.B.L.; Strenzel, G.M.R.; Maida, M.; Araújo, T.C.M., and Ferreira, B.P., 2020. Multiresolution satellite-derived bathymetry in shallow coral reefs: Improving linear algorithms with geographical analysis. Journal of Coastal Research, 36(6), 1247–1265. Coconut Creek (Florida), ISSN 0749-0208.

Bathymetric maps are one of the first steps for most hydrological and ecological studies of the seascape, as depth is a determinant factor in the distribution of organisms, patterns of wave exposure, and coastal circulation. The coral reefs of Tamandaré-Brazil, located at Costa dos Corais marine protected area (MPA), encompass a mosaic of interconnected habitats of complex geomorphology, including coral reefs, algal, and seagrass beds. These coastal habitats are subjected to chronic impacts such as sedimentation, reef erosion, and increasing human use, leading to habitat loss. Despite their social and ecological importance and the conservation measures in place, bathymetric and habitat maps of this coast are lacking. Indeed, in situ surveys are not always feasible in shallow coral reef areas. The present study offers a detailed bathymetric mapping of the area using multiresolution satellite imagery. One Landsat-8 (December 2016) and one WorldView-03 (February 2017) imagery were used to derive medium (30-m) and high-resolution (2-m) bathymetry of the study area. Single-beam echo sounder surveys were performed to obtain field data to calibrate the depth-retrieving algorithms: linear model, ratio band model, principal component analyses of the transformed bands, and geographically weighted regressions (GWR). For both resolution datasets, results showed that the algorithms' RMS were significantly improved by the GWR technique (RMS > 0.9) because of adaptability to the bottom heterogeneity found in complex areas such as coral reefs. Specific geomorphological reef zones were recognizable in the resulting bathymetric maps, such as intrareef lagoon, reef crest, fore-reef, and reef flat. This research concluded that affordable methods such as single-beam data coupled with satellite imagery through GWR can provide the required inputs for mapping shallow areas with complex relief. Such results may be further used to habitat mapping, necessary to inform the multiple-use zonation foreseen in MPA management plans.

Gurung, D.P.; Chen, N.; Waguespack, Y.; Ruby, D.E.; Ishaque, A.B., and Chigbu, P., 2020. Phosphorus speciation and bioavailability in the surface sediments of Maryland coastal bays. Journal of Coastal Research, 36(6), 1266–1277. Coconut Creek (Florida), ISSN 0749-0208.

Phosphorus (P) is an essential nutrient for phytoplankton growth and biochemical processes. In shallow coastal lagoons, there is strong coupling between water column and sediments in terms of P dynamics. To better understand dynamics and bioavailability of P in Maryland coastal bays (MCBs), surface sediment samples were collected at 13 sites of MCBs in May, August, October, and December in 2013 to assess the major reservoirs using a six-step sequential P extraction procedure. The objectives of this study were (1) to determine the spatial/temporal variations of P species in MCB sediment and to assess the relationship of P species at various locations with material sources and sediment types, and (2) to assess the bioavailability of sedimentary P in the study area. The average percentages of fractions of P of four months (representing four seasons) in surface sediments were Det-P (33.5 ± 4.36%) > total organic P (27.2 ± 3.43%) > Fe-P (13.0 ± 1.36%) > Al-P (12.2 ± 1.25%) > authigenic P (11.1 ± 2.86%) > L.Adsorp-P (3.0 ± 0.38%). On average, bioavailable P in surface sediments accounted for 55.4% of total P and thus represented a significant proportion of the sedimentary P pools in MCBs. Total P (TP) in the surface sediment ranged from 309.8 to 1345.4 µg/g with an average of 874.5 ± 343.3 µg/g. There was a strong positive relationship between TP and sediment grain size (mean phi) such that sites with the finest sediments (clay-silt) closest to the mouths of tributaries had significantly higher TP than sites with coarser grains.

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.

Li, Y.; Wei, B.; Suo, A.; Zhang, Z.; Xu, Y., and Liang, Y., 2020. Spatial and temporal coupling relationships of coastline exploitation and environmental carrying safety in Ningbo, China. Journal of Coastal Research, 36(6), 1292–1301. Coconut Creek (Florida), ISSN 0749-0208.

Spatial correlations and conflicts arise between the intensity of the spatial exploitation of the coastal zone and its environmental carrying safety, which refers to the ability of resources in the coastal zone and the environment to withstand human activities and disasters. To study the spatial and temporal coupling relationships between the suitability of exploitation of the coastal space and its environmental carrying safety, a model to assess the suitability of the coastline was established using spatial difference, overlay analysis, cluster analysis, and the analytic hierarchy process, a coastline carrying safety model was constructed according to a standard for the intensity of coastline exploitation and an artificial index, a model for spatial–temporal coupling was used to analyze the correlation between the suitability of the coastline and results of the assessment of its carrying safety. The results for the Ningbo coastline showed the following: (1) The length of the productive coastline increased from 176.09 km to 218.82 km and that of the ecological coastline decreased from 329.99 km to 305.74 km, which shows that the Ningbo coastline is being developed more intensely. (2) The length of the coastal carrying safe zone in Ningbo increased from 488.78 km to 568.05 km and that of the critical carrying and unsafe zone decreased from 311.32 km to 255.15 km which shows that Ningbo has gradually achieved sustainable development by upgrading its industrial infrastructure and raising ecological awareness. (3) In terms of space, the suitability of exploitation of the coastline of Ningbo had a significant negative correlation with its level of carrying safety. This indicates that the exploitation of the coastal zone in Ningbo has put pressure on carrying safety in the region in recent years.

Palemón-Arcos, L.; Torres-Freyermuth, A.; Gutiérrez-Can, Y.; Gómez-Arredondo, C.M.; Bojórquez-Mora, E.; Pintado-Patiño, J.C., and Hernández-Hernández, M.-A., 2020. Numerical assessment of tsunami-structure interaction (Guerrero, Mexico). Journal of Coastal Research, 36(6), 1302–1312. Coconut Creek (Florida), ISSN 0749-0208.

A numerical modelling framework for the study of tsunami-structure interaction is presented. In this work, a Reynolds-Averaged Navier-Stokes (RANS) equation nonlinear wave transformation numerical model is coupled to a structural model to investigate wave-structure stability and functionality. Different tsunami breaking types interacting with an existing sheet-pile quay wall located at the coast of Guerrero (Mexico) were considered for two structure conditions (newly built and deteriorated). The depth- and temporal-dependent pressure field on the protective wall was employed to determine the structural response. Furthermore, the numerical framework allowed the overtopping volumes to be quantified. Numerical results show that structural failure under tsunami waves is sensitive to both the breaking type and the degree of deterioration of concrete and steel. Numerical results also suggest that the quasi-dynamic approach written in the guideline codes for tsunami design is not suitable. Hence, a nonhydrostatic approach is required for proper design of coastal protection structures exposed to tsunami loads.

Carvache-Franco, M.; Carvache-Franco, W.; Carvache-Franco, O., and Hernández-Lara, A.B., 2020. Analysis of push and pull motivations and the intentions to return and recommend a coastal or marine destination. Journal of Coastal Research, 36(6), 1313–1322. Coconut Creek (Florida), ISSN 0749-0208.

Visiting coastal and marine destinations can be appealing for tourists depending on the on-site activities offered. This study analyzed push and pull motivations to establish their effect on visitors' intention to return and likelihood to recommend a tourist destination. The research was conducted in the city of Salinas in Ecuador, a renowned tourist destination with coastal and marine, natural, and cultural features. For the statistical procedure, factor analysis was used as a data reduction technique, and multiple regression analysis was conducted to select the motivational variables that predict the intentions to return and recommend the destination. The results show two push motivational factors, “escape and novelty,” and “knowledge and experience,” and two pull motivational factors, “active marine,” and “static marine.” The first pull motivational factor is related to marine sports, swimming in the ocean, and adventurous activities, and the second one is associated with clear water and fresh air enjoyment, walking along the beach, and beaches of scenic beauty. The push factor “escape and novelty” and the pull factor “static marine” were the most important predictors of the intentions to return and recommend a coastal and marine destination. These findings will help coastal and marine planners to implement sustainable development strategies according to the characteristics of the demand.

Wang, C.; Wang, D.; Yang, J.; Fu, S., and Li, D., 2020. Suspended sediment within estuaries and along coasts: A review of spatial and temporal variations based on remote sensing. Journal of Coastal Research, 36(6), 1323–1331. Coconut Creek (Florida), ISSN 0749-0208.

Suspended sediment is an essential factor in the ecological environment of estuaries and coasts because it significantly affects the optical properties of the water body. Studies on suspended sediment concentration in estuaries and coasts have garnered attention for a long time. Remote sensing is important in the monitoring of suspended sediment. Previous studies have made considerable technological and theoretical progress and obtained significant achievements. However, several current studies have focused on the establishment of suspended sediment–retrieval models. There is still considerable scope of extensive and applied research on suspended sediment in estuaries and coasts. Based on a general retrospect of research studies on suspended sediment, this article summarizes the processes and tendency of suspended sediment development and provides perspectives for future studies on suspended sediment in estuaries and coasts. These perspectives include (1) increased focus on the examination of the suspended sediment–retrieval model of the multiple-band forms belonging to nonmonotonic functions and aimed at improving applicability, (2) strengthened research on the impacts of extreme weather conditions on suspended sediment concentration to identify the features of abnormal changes, and (3) increased effort in the research of long-term spatial and temporal variations of suspended sediment concentration in estuaries and coasts to promote better understanding of the rules and trends of its change.

Yang, Q.; Dong, W.; Xu, Z., and Huang, X., 2020. SFM-MAC: Multichannel MAC protocol for underwater sensor networks based on underwater passive localization mechanisms. Journal of Coastal Research, 36(6), 1332–1342. Coconut Creek (Florida), ISSN 0749-0208.

With the continuous development of ocean research in recent years, underwater acoustic sensor networks, as the extension of terrestrial wireless sensor networks (WSNs), play an increasingly important role in ocean and coastal research. To solve the problem of spatial unfairness caused by spatiotemporal uncertainty of underwater acoustic signal propagation in underwater WSNs and improve the throughput of underwater networks, this paper proposes a slotted-floor multichannel medium access control (SFM-MAC) protocol based on a single transceiver. SFM-MAC uses an underwater passive localization algorithm to obtain location information and then transforms spatiotemporal information to avoid the synchronization of the whole network to reduce the spatiotemporal uncertainty of underwater networks; further, it uses request to send (RT)/channel announcement/channel listening/clear to send (CTS) handshaking mechanism to avoid multichannel hidden terminal problems and achieve fair access. In addition, the paper uses the Markov chain to construct the reservation model of control channels, and theoretically analyzes and calculates the theoretical throughput of the multichannel MAC protocol under the condition of reserved collision. Simulation experiments show that the network fairness index of SFM-MAC is 15% higher than that of traditional RTS/ CTS protocols. The effective network throughput of SFM-MAC in different business scenarios is 60–70% and 12–15% higher than the single-channel underwater MAC protocol SF acquisition multiple access and the multichannel underwater MAC protocol, respectively.