Potter, C. and Amer, R., 2020. Mapping 30 years of change in the marshlands of Breton Sound basin (southeastern Louisiana, U.S.A.): Coastal land area and vegetation green cover. Journal of Coastal Research, 36(3), 437–450. Coconut Creek (Florida), ISSN 0749-0208.

This study analyzes the 30-year record of Landsat satellite imagery to better understand the patterns and processes of land loss/gain and recent changes in marshland vegetation green cover in coastal wetlands of Breton Sound basin of southeastern Louisiana. Impacted by both Hurricane Katrina in 2005 and Hurricane Gustav in 2008, this vast estuary area just south of New Orleans was mapped at 30 m resolution in 5-year intervals from 1985 to 2017 using the Landsat Normalized Difference Water Index (NDWI) and the Normalized Difference Vegetation Index (NDVI). Results revealed an entirely new picture of marshland change prior to Hurricanes Katrina and Gustav in the Breton Sound basin. Following decades of extensive wetland loss resulting largely from gas and oil well drilling and canal construction, this analysis estimated gains in land area between 1985 and 2005 (pre-Katrina) of 247 km² across all subbasins of Breton Sound. The largest proportional increases in marshland areas were mapped from dNDWI analysis in the subbasins of Bayou la Loutre, Bayou Pointe-en-Pointe, and Bayou Terre Aux Boeufs, all surrounding the outer Mississippi River Gulf Outlet Canal. Brackish salinity areas were among the first of Louisiana's coastal wetlands to succumb to the hurricane storm surges of 2005 and 2008, as Landsat dNDWI analysis estimated that about 245 km² of wetlands in the Breton Sound basin were lost to open water from the impacts of Hurricanes Katrina and Gustav. However, combined dNDWI and dNDVI analysis indicated that gains in marshland area and green vegetation cover have occurred at a yearly rate of increase after 2008 comparable to the period between 1985 and 2005. Specific areas of rapid land gain were detected in River aux Chenes and Bayou Bienvenue subbasins, and Bayou Plaquemines and Bayou la Loutre in brackish to saltwater marshland types on the outer margins of Breton Sound basin.

Gough, W.A. and Shi, B., 2020. Impact of coastalization on day-to-day temperature variability along China's east coast. Journal of Coastal Research, 36(3), 451–456. Coconut Creek (Florida), ISSN 0749-0208.

Annual day-to-day temperature variability is examined for 16 urban areas along China's east coast. This day-to-day temperature framework was used to compare these cities and to discern differences between coastal locations and those inland from the coast. The day-to-day variation of the minimum temperature of the day was found to be the clearest indicator of coastalization, particularly when the effects of latitude were included. In addition, this metric was found to be superior and more nuanced than traditional measures of continentality and coastalization. An inland transect from Shanghai Pudong to Nanjing within the Yangtze River delta is suggestive of the relationship between the day-to-day temperature metrics and inland displacement and elevation. This work supports the further utility of the day-to-day temperature variation framework in detecting subtle changes in the thermal response to local meteorological and geographical features and may provide a useful tool for assessing marine impacts on climate data.

Finkl, C.W. and Makowski, C., 2020. Lateral extrapolation of coastal catenary sequences using the Biophysical Cross-shore Classification System (BCCS) to create shore-parallel situational zonation mapping units. Journal of Coastal Research, 36(3), 457–471. Coconut Creek (Florida), ISSN 0749-0208.

The Biophysical Cross-shore Classification System (BCCS), which uses transects to assess shore-normal ecological and geomorphological successions from offshore to onshore within a coastal belt (Finkl and Makowski, 2020a), also provides a basis for extrapolating cross-shore catenas into shore-parallel units. This paper shows that three-dimensional transects can be parameterized in terms of alongshore breadth as well as cross-shore width and depth below or elevation above sea level. The codification of cross-shore environments and habitats in the framework of the BCCS provides an interpretative basis for determining the lateral extent of transect units (archetypes and sub archetypes) by lateral extrapolation to polygonal mapping units. The method discussed here is akin to geological cores or cross-sections that are used to laterally extrapolate units within vertical sequences. Repetitive successions of archetypes, based on cross-shore ecological interpretation of satellite imagery, results in a common master sequence referred to as a Dominant Catenary Sequence (DCS). The DCS is composed of generic archetypes, such as Barrier, Beach, Beach Ridge, Cliff, Coral Reef, Delta, Dune, Flat, Ice, Lagoon, Mountain, Rock, Till (Glacial Material), Upland, and Wetland. The more detailed Coastal Ecological Sequence (CES) of a coastal belt, which is defined by a discrete codification sequence built up from the DCS, is formulated by cognitive geovisual analytics to link the dominant catena with a numbered shore-parallel shape distinction and subscripted sub archetypes to refine the sequential composite archetypes in a DCS. Once the DCS- or CES-labeled transect has been plotted on a satellite image, the identified shore-normal units can be extrapolated into shore-parallel polygons by traditional (i.e. visual, cognitive) image interpretive and mapping techniques to show the spatial extent of classified archetypes and sub archetypes.

Sutherland, T.F. and Amos, C.L., 2020. An in situ assessment of seabed stability in Baynes Sound, British Columbia, Canada. Journal of Coastal Research, 36(3), 472–486. Coconut Creek (Florida), ISSN 0749-0208.

The Sea Carousel, an annular flume, was deployed to examine (in situ) fundamental parameters of seabed stability in Baynes Sound, British Columbia, Canada. Sediment grain size, water and organic contents, and chlorophyll and phaeopigment concentrations were collected to establish a hierarchy of factors associated with seabed stability. Sediment stability increased toward the Sound entrance in concert with decreases in water, organic, and silt–clay contents and a transition from cohesive to noncohesive properties. Bed-stress estimates, based on the quadratic stress law and turbulent kinetic energy (TKE) methods, showed a decrease in the drag coefficient from the inner (0.04) to the outer (0.0015) Sound. Surface erosion thresholds ranged between 0.04 to 0.28 Pa, whereas the friction coefficients (e.g., the failure envelop) were on average 12°, representing normally consolidated sediments. Type I (floc) erosion occurred at low shear stresses, whereas type II (mass) erosion happened at higher values. Erosion rates (E, for type I erosion) fitted a power function of excess shear stress (E^m = τ0 – τ_crit,z)m with zero offset, where 0.81 < m < 2.32. The lowest and highest values for a given excess-shear stress occurred in the inner Sound and outer Sound, respectively. Settling of (resuspended) sediment after an exponential decay law [d(SSC)/dt] = SSC₀ (exp^–kt), where k fell within that of published values (3 < k < 539). Higher values of k (fastest settling) were observed in the inner Sound relative to the outer Sound. The sedimentation diameter (d_s) fell in a coarse–silt to fine-sand range and was larger in the outer Sound, reflecting a coarsening of bed sediments.

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.

Al-Aesawi, Q.; Al-Nasrawi, A.K.M., and Jones, B.G., 2020. Short-term geoinformatics evaluation in the Shatt Al-Arab delta (northwestern Arabian/Persian Gulf). Journal of Coastal Research, 36(3), 498–505. Coconut Creek (Florida), ISSN 0749-0208.

Riverine deltas are records of past hydrosedimentary conditions, in conjunction with nearshore tidal and wave dynamics. Within recent human developments, these variables have been affected by increased global warming as well as anthropogenic modifications on the feeder catchment, the delta itself, and the active/discharge channel. This paper investigates the recent (1971–2016) changes at the mouth of the Shatt Al-Arab delta, which includes migration of the navigation channel to inside the Iraqi border. Farther upstream, the channel is migrating toward the Iranian side. A mapping study was conducted with new data obtained from bathymetric surveys as used in the digital shoreline analysis system in GIS applications. The results highlight significant changes regarding the shoreline positions and rates of erosion and sediment accumulation. Additionally, mapping the coastal dynamics has revealed significant shoreline migration with differences between the left and right sides of the river mouth and an increased salinity intrusion up the channel. The effect of these findings could potentially affect the classification of the river mouth, changing it from delta to estuary and affect the international demarcation border.

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.

Li, J.; Xia, W.; Liu, L.; Zhang, M.; Zhao, B.; Liu, J.; Meng, M.; Zhao, Y., and Guo, J., 2020. Influence of kaolin on the formation and sedimentation of oil-colloidal particle aggregates in marine environments. Journal of Coastal Research, 36(3), 521–527. Coconut Creek (Florida), ISSN 0749-0208.

Spilled oil in the marine environment is dispersed into droplets under the action of waves and currents, forming oil-colloidal particle aggregates (OcPAs) in the presence of clay particles in the ocean. Kaolin, which is a typical representative of clay particles, was investigated for its influence on the morphology and sedimentation characteristics of OcPAs in this work. Results have displayed that OcPAs exist mainly in the forms of single drop, double drops, and multiple drops, and their morphology is mainly affected by the turbulence intensity and kaolin concentration in seawater. Furthermore, it is observed that under medium- and high-turbulence intensity, the larger the fractal dimension of OcPAs is, the smaller the settling velocity becomes. The results suggest that the spilled oil can be removed from the sea surface by adding clay particles to promote the formation of OcPAs with large particle size and rapid settling velocity.

Lee, J.-S.; Son, D.-H.; Lee, S.-H.; Myeong, H.-H.; Cho, J.-S.; Lee, J.-C.; Lee, J.-Y.; Park, C.-S., and Kim, J.-W., 2020. Canonical correspondence analysis ordinations and competitor, stress tolerator, and ruderal strategies of coastal dune plants in South Korea. Journal of Coastal Research, 36(3), 528–535. Coconut Creek (Florida), ISSN 0749-0208.

The distribution of plant communities in the sand dunes of the SW coasts of South Korea was studied, along with environmental factors and plant traits, by canonical correspondence analysis (CCA). The competitor, stress tolerator, and ruderal (CSR) ecological strategies were also evaluated. The coastal sand dune plants were classified into two plant trait groups in the CCA biplot diagram. First, vegetation was correlated with leaf dry weight, canopy height, specific leaf area, leaf dry matter content, and lateral spread. Second, it was correlated with the flowering period and flowering start. Coastal sand dune plants were classified into three soil factor groups in axes 1 and 2 of the CCA biplot diagram. First, the vegetation was correlated with total nitrogen (T-N), K⁺, Silt, Mg²⁺, Na⁺, and clay contents. Second, it was correlated with Ca²⁺. Third, it was correlated with the sand contents. To elucidate the relative significance of competition, stress, and disturbance in the distribution process of plant communities, the CSR distribution model was adopted. Many coastal plants (12 species) showed competitor-ruderal/competitor-stress-tolerant-ruderal strategies: Artemisia fukudo, Atriplex gmelinii, Carex kobomugi, Calystegia soldanella, Digitaria ciliaris, Linaria japonica, Messerschmidia sibirica, Oenothera bieenis, Salicornia europaea, Salsola komarovii, Suaeda glauca, and Suaeda maritima. The four species with stress-tolerant-competitor/competitor-stress-tolerant-ruderal strategies were Carex pumila, Imperata cylindrica var. koenigii, Limonium tetragonum, and Zoysia sinica. Conyza canadensis, Ischaemum anthephoroides, Phragmites communis, and Vitex rotundifolia displayed competitor/stress-tolerant-competitor, competitor-ruderal, stress-tolerant-competitor, and C/SC strategies, respectively. The differences in distribution and restoration patterns of the CCA diagrams and CSR triangles may be attributable to different adaptions of plant traits or soil factors.

van Haren, H., 2020. High-resolution temperature observations of a shallow lagoon in the South Pacific (Bora Bora). Journal of Coastal Research, 36(3), 536–544. Coconut Creek (Florida), ISSN 0749-0208.

The daily cycle of heating and cooling of the near-surface ocean may be quite different in the open ocean compared with a shallow lagoon with a seafloor that is a few meters deep and can be heated directly by the sun. This solar radiation can affect the local benthic communities. To study the physical processes associated with the daily cycle of the South Pacific lagoon surrounding Bora Bora, a vertical string of five high-resolution temperature sensors is moored at a 2-m-deep site for 3 weeks. Besides standard ocean warming (mostly during the day) and cooling (mostly at night), the sensors show relatively highest temperature near the lagoon floor during the warming phase and weakly stable stratification toward the end of the cooling phase. During the warming phase, highly variable stratification is observed extending into the water column, but only under conditions of calm weather and turbid waters. Under trade winds and clear waters, the lowest sensor or sensors show consistently higher temperature variability than higher sensors with spectral slopes indicative of shear and/or convective turbulence. During the cooling phase, the lower sensor shows consistently very low variance (nonturbulent), while other sensors show a spectral slope around the buoyancy frequency, evidencing weakly stratified waters supporting internal waves. These observations contrast with open-ocean near-surface observations of stable stratification during the warming phase and turbulent free convection during the cooling phase. Thus, lagoons seem to resemble the atmosphere more than the ocean in daytime thermodynamics and possibly act as a natural solar pond with bottom conductive heating (when salinity compensates for unstable temperature variations).

Schweiger, C.; Koldrack, N.; Kaehler, C., and Schuettrumpf, H., 2020. Influence of nearshore bathymetry changes on the numerical modelling of dune erosion. Journal of Coastal Research, 36(3), 545–558. Coconut Creek (Florida), ISSN 0749-0208.

Coastal dunes are an essential protection measure at the German Baltic Sea coastline. As the breaching of dunes during a storm is very complex and detailed data is still rare regarding the evolution, width and the depth of the breach and how the hinterland will fill through a breach and empty after drawdown, the aim of the collaborative project PADO is to investigate how a real dune breaches during a storm and how the hinterland is flooded. Within the scope of a physical model test, a large-scale research dune was built at the beach of Rostock-Warnemuende in Germany. During the modelling, the nearshore bathymetry was measured monthly and a high variability was observed. The objective of this study was to investigate the influence of a varying initial nearshore bathymetry on the results of coastal erosion modelling. Therefore, four XBeach models which differed only in nearshore bathymetry were set up and forced with a storm surge event from October 2017. The results were analyzed with regard to the computed post-storm bed level. Using the nearshore bathymetry of July and November 2017, large amounts of the research dune are eroded. The eroded sediment minor decreases when the nearshore bathymetry of September 2017 is applied. On the contrary, the sole use of freely accessible bathymetry data leads to significant decrease in the computed dune erosion. This leads to the conclusion, that the initial nearshore bathymetry can have a significant influence on the computed post-storm bed level. Especially when only freely accessible bathymetry data can be used, deviations between post-storm measurements and computed dune erosion can occur. This might be due to out-of-date data or a too coarse resolution. The results also show that pre-storm bathymetric measurement does not necessarily have to have a high resolution in order to achieve reliable results.

Jeong, D.U.; Lee, Y.G.; Kang, J.; Woo, H.J., and Choi, Y.H., 2020. Sediment geochemistry and benthic foraminiferal response to fish farming after conversion from a red laver (seaweed) farm. Journal of Coastal Research, 36(3), 559–574. Coconut Creek (Florida), ISSN 0749-0208.

To understand the effects of biodeposits discharged from a fish farm (which was previously a red laver farm) on geochemistry of the sediment and benthic ecology, trace metals and element analyses, ²¹⁰Pb dating, and benthic foraminiferal analyses were conducted on sediment cores collected below the fish farm cages. Sediment core sampling was also carried out at a control plot (160 m away) to understand the spreading of biodeposits. The geochemical effect of fish farming is pronounced. There was an increase in silt content and sedimentation fluxes of Zn_ex (Zn in excess fractions), Cu_ex, As_ex, and TP_ex (total phosphorus in excess fractions) after red laver farming. The silt content increased from 45.01% to 50.07%, with a sediment accumulation rate of ∼0.61 cm/y, on average. TP_ex, with 0.15% ± 0.06% on average, showed that the fish farming effects increased by 0.22% ± 0.07%. Zn_ex, Cu_ex, Cd_ex, and As_ex showed a positive relationship with TP_ex increase: 19.92 ± 1.79, 10.23 ± 3.99, 0.57 ± 0.19, and 0.92 ± 0.04 µg/cm²/y, respectively. The high sedimentation fluxes of Zn_ex and As_ex in the control plot may signify an expansion of influence of the fish farm by tidal currents. Seven benthic foraminifera appeared during the fish and red laver farming periods, with the dominant species being Cribroelphidium excavatum; however, they were characterized by a high similarity index of 88.1% and very low frequency of abundance, indicating bad habitat conditions. Among them, the C. excavatum–Ammonia beccarii–Ammonia ketienziensis–Cribroelphidium subarcticum assemblage ranged from 21 cm depth to the uppermost layer, characterized by increases in A. beccarii. This increase may have been caused by the accumulation of organic matter discharged from the fish farm after red laver farming, rather than from an increase in the trace metals. A. beccarii may be a species tolerant to fish farming.

Stubbs, Q.; Yeo, I.-Y.; Lang, M.; Townshend, J.; Sun, L.; Prestegaard, K., and Jantz, C., 2020. Assessment of wetland change on the Delmarva Peninsula from 1984 to 2010. Journal of Coastal Research, 36(3), 575–589. Coconut Creek (Florida), ISSN 0749-0208.

The decline in wetland extent and condition emphasizes the need for sound wetland restoration and conservation policies, which require baseline information on wetland status, change, and change drivers. Multiple wetland maps are available, but they can be quite inconsistent bcause of different input and generation techniques, dates, and objectives. Moderate-resolution (30 m²) regional land-cover data sets (LCDs) were analyzed to (1) quantify historical wetland changes on the Delmarva Peninsula at multiple spatial scales between 1984 and 2010, (2) identify differences in the spatial area of wetland change and discuss the source of and implications for these differences, and (3) investigate the extent to which drivers of wetland change can be identified using existing LCDs. The following regional LCDs were considered: the National Oceanic and Atmospheric Administration Coastal Change Analysis Program (C-CAP), the U.S. Geological Survey (USGS) Chesapeake Bay Land Cover Data Series (CBLCD), and the USGS National Land Cover Database. The C-CAP and CBLCD had the highest spatial agreement at 97%, and an average of 76% spatial agreement with the U.S. Fish and Wildlife Service National Wetland Inventory. The highest percentages of net wetland loss occurred between 1992 and 2001, whereas net wetland gain occurred between 2001 and 2010. Wetlands were predominantly converted (e.g., lost) to croplands/grass/shrubs (67%) and water (11%), which could be linked to drivers such as agriculture and sea-level rise.

Cao, K.; Sun, W.; Chen, L.; Meng, J., and Zhang, J., 2020. Retrieval and analysis of sea surface salinity in the adjacent waters of the Yangtze River Estuary based on multisource satellite data. Journal of Coastal Research, 36(3), 590–599. Coconut Creek (Florida), ISSN 0749-0208.

Moderate Resolution Imaging Spectroradiometer, Sea-Viewing Wide Field-of-View Sensor, and Visible Infrared Imaging Radiometer Suite multisource satellite remote sensing reflectance data are used with in situ sea surface salinity (SSS) measurements in the Yellow Sea and East China Sea. A linear algorithm is developed for the retrieval of summer SSS in adjacent waters of the Yangtze Estuary in the Yellow Sea and East China Sea. The accuracy of SSS retrieval results is validated using independent in situ measurements. Results show that the mean bias of the model is –0.34 psu, the root-mean-square error is 1.55 psu, and the correlation coefficient is 0.80. The linear model is extended to the retrieval of multisource satellite monthly remote sensing reflectance data to obtain monthly SSS products of the Yangtze Estuary. The spatial coverage of fused satellite SSS data is about 10% greater than that of single-satellite monthly retrieved SSS data. The SSS in the Yangtze Estuary research area has lower values nearshore and higher values offshore. The SSS gradually rises from nearshore areas to open water, and an obvious low-salinity water tongue forms in the Yangtze Estuary. The eastward expansion of freshwater flows of the Yangtze River into the sea is mainly affected by the runoff of the Yangtze River, while a southerly wind and northeastward flow in the research area are the main factors responsible for the eastward expansion of the Yangtze River freshwater flows to the NE. The effect of freshwater on the Yellow Sea and East China Sea extends to 125.5^° E, and the low-salinity freshwater tongue distributes northeastward. The expansion types of the Yangtze River freshwater include NE expansion, N-NE expansion, E-NE expansion, bidirectional expansion, and nondirectional expansion.

Guo, Y.; Chen, Y.; Liao, B.; Huang, B.; Wu, F., and Jiang, Z., 2020. The effect of vegetation on surface elevation in coastal mangrove areas. Journal of Coastal Research, 36(3), 600–607. Coconut Creek (Florida), ISSN 0749-0208.

Rising sea levels pose a serious threat to global coastal mangroves. The ability of surface elevation to change synchronously with rising sea level is the key to the survival of mangroves. Mangrove vegetation can have a variety of effects on surface and subsurface processes; therefore, it has an important role in surface elevation changes. In this study, rod surface elevation table–marker horizon (RSET-MH) technology was used to study changes in surface elevation and accretion between nonvegetated and vegetated mangrove areas at three different sites. The results showed that the existence of vegetation had a significant effect on elevation changes, with increased surface elevation in vegetation areas observed to be significantly greater than those in nonvegetation areas. In addition, the subsurface changes in vegetated area showed expansion, whereas the nonvegetation area showed subsidence. Surface accretion showed variable trends in different research sites, although these could be related to their geographical location and thus be affected by many factors. Moreover, there was a significant correlation between density of vegetation and elevation/subsurface changes (r = 0.763, p < 0.05; r = 0.714, p < 0.05 respectively), and there were no significant correlations between accretion and vegetation characteristics. The results indicate that mangrove vegetation has a positive effect on the increase of surface elevation, and vegetation density may be a key factor because of the high biomass and carbon storage rate in high-density areas. This study provides additional data with which to explore the elevation variation in mangroves and a scientific basis and technical support for strengthening wetland protection.

Guo, Q.; Zhang, J.; Hu, Z., and Zhou, Z., 2020. Hydrochemical and isotopic evolution of groundwater flowing downstream of the Daqing River (Liaodong Bay, China). Journal of Coastal Research, 36(3), 608–618. Coconut Creek (Florida), ISSN 0749-0208.

Hydrochemistry and specific environmental isotope ratios (δD, δ¹⁷O, and δ¹⁸O) were employed to investigate the hydrochemical and isotopic characteristics of groundwater in the downstream coastal plain of the Daqing River, China. The relative abundance of the major cations and anions of groundwater along the Daqing River changed from Ca²⁺, Mg²+ to Na⁺, Ca²⁺ and from to Cl^–, respectively. The samples, divided into different groups on the basis of correlation coefficients, showed that the chemical composition of the groundwater samples near the Daqing River is approximately consistent with that of the Daqing River. The saturation indices calculated by PHREEQC software indicated that the main hydrogeochemical processes are evaporation and concentration along groundwater flow paths from the upper zone to the middle zone of the Daqing River basin. However, in the down zone, calcite, anhydrite, and dolomite become supersaturated. Isotopic data reveal that the groundwater is affected by the strong evaporation along the Daqing River. In the down zone of the Daqing River, the groundwater is polluted by the seawater.

Moody, J.A.; Gentry, M.J.; Bouboulis, S.A., and Kreeger, D.A., 2020. Effects of substrate (protection and type) on ribbed mussel (Geukensia demissa) recruitment for living shoreline applications. Journal of Coastal Research, 36(3), 619–627. Coconut Creek (Florida), ISSN 0749-0208.

Ribbed mussels are the functional dominant species in eastern U.S. salt marshes, providing particulate nutrient filtration and enhanced vegetative growth services. Wetland loss in the Delaware Estuary has resulted in ribbed mussel population declines and increased interest in ecological restoration practices, such as living shorelines. Incorporation of ribbed mussels into restoration applications represents an opportunity to enhance ecological structure and function in shoreline stabilization projects. Since 2008, the Partnership for the Delaware Estuary has implemented 14 living shorelines, with ribbed mussel recruitment exhibiting temporal and spatial variability. To better understand sources of this variability, a three-tiered study was employed to evaluate differences in ribbed mussel recruitment: (1) on previously deployed substrates (2009–10); (2) on exposed vs. protected surfaces; and (3) across a variety of substrates. Results showed that on aged living shorelines, ribbed mussel density was greater on oyster shell bags than on coir fiber logs and the unaltered marsh edge. On newly deployed experimental materials, recruitment was higher on the surface of shell bags when protected by mesh but was only <8% of total bag recruitment and did not differ between protected and unprotected shell bags. Mussel recruitment was greater on oyster shell and Oyster Castle^® than on coir fiber recruitment tiles, and also on those protected by shell bag mesh than by coir fiber or without protection. Therefore, living shorelines that incorporate ribbed mussel refuge in the form of protected surfaces and interstitial space can facilitate recruitment and persistence, enhancing populations and their associated water quality services.

Lin, J.; Zhao, D.; Guo, C.; Zhang, Z., and Su, Y., 2020. Numerically modeling the effect of flexibility on flow around marine engineering structures: Using the shape of the saguaro cactus. Journal of Coastal Research, 36(3), 628–635. Coconut Creek (Florida), ISSN 0749-0208.

The cylinder is an essential infrastructure with a wide range of applications in the engineering fields of shipping, aviation, and construction. The study of the hydrodynamic performance of a cylinder is a current research focus that can provide a more direct reference for the optimized design of its structure. In this study, the principles of bionics and flexible materials are applied to the research of marine structures, and the shape of the saguaro cactus is used as a reference. Considering the influence of flexible materials, a numerical simulation that provides a new route for the research and design of cylinders in the engineering field is performed. Based on the morphological characteristics of the cactus, a three-dimensional model and its fluid-solid control domain are established. Numerical simulations of the flow around rigid and flexible models with different Reynolds numbers are carried out. The lift, drag, flow field characteristics, and structural deformation are obtained. A turbulent vortex street is created by the flow around the cylinder. Vortex-induced vibration is generated, which demonstrates apparent three-dimensional characteristics. In a majority of the cases, flexible materials and irregular cross-sectional shapes have a clear influence on the flow around the cylinder.

Alfaifi, H.; Mohammadian, A., and Bonakdari, H., 2020. Experimental investigation and model development of geometric characteristics of negatively buoyant jets inclined at 15^° and 52^° using GMDH method. Journal of Coastal Research, 36(3), 636–653. Coconut Creek (Florida), ISSN 0749-0208.

The goal of this study was to provide more experimental data on the main geometric characteristics of an inclined negatively buoyant jet discharged into deep stagnant water, as well as to use the data for developing and evaluating the performance of the proposed model. Series of laboratory experiments were performed using a high-resolution digital camera to determine the main geometric characteristics of two jet discharge angles, 15^° and 52^°. Various densimetric Froude numbers (Fr_d) were used in this study, ranging from 11 to 75. The results showed that the behavior of the jet is significantly affected by the Fr_d and the initial discharge angle (θ). A comparison of the present results with previously reported data showed good agreement for all geometric parameters, especially for the angle of 15^°, while the 52^° values differed slightly. A nonlinear method (artificial neural network, ANN) called the group method of data handling (GMDH) was employed in this study to develop explicit equations for the geometric characteristics of the two studied angles. This method has not previously been used in the prediction of mixing of inclined dense jets. Moreover, different statistical indices were utilized to evaluate the accuracy of the proposed equations. The values of R-squared (R²) and the mean absolute percentage error (MAPE) for the geometric characteristic ranged between 0.964 to 0.995 and from 2.6% to 8.4% respectively, which indicate that the GMDH model performed very well. The GMDH results provided good predictions for both angles for the data used within this study.

Violante-Carvalho, N.; D'Avila, V.; Heringer Villena, H.H., and Mendonça Filippo, A.M., 2020. The Flying Anchor: An original technique for beach profile measurements in the surf zone. Journal of Coastal Research, 36(3), 654–660. Coconut Creek (Florida), ISSN 0749-0208.

An original method is proposed to measure beach profiles in the surf zone. Surveying this dynamic and energetic region is usually a challenge when waves are large, which is exactly when the nearshore processes are more intense. The lack of bathymetry and wave data is indisputably a limiting factor hindering the understanding of the physics involved. Countless techniques have been proposed in the last decades to increase the temporal and spatial density of such measurements, with different degrees of success. Seeking to bring new approaches to address these issues, the proposed operation consists of launching a specially designed anchor from the beach face over the surf zone, carrying a graduated cable. When the cable is drawn taut, a pressure sensor is hand towed along the sea floor measuring the profile, as well as yielding the wave energy spectrum. The technique is efficient and fast and employs a small team at a very low cost. Some of the main limitations of the known in situ techniques, such as sea state dependency, high cost per profile, and longshore drift, are mitigated.

Temple, N.A.; Webb, B.M.; Sparks, E.L., and Linhoss, A.C., 2020. Low-cost pressure gauges for measuring water waves. Journal of Coastal Research, 36(3), 661–667. Coconut Creek (Florida), ISSN 0749-0208.

Waves have profound effects on coastal geomorphology, but the understanding of wave climate effects on coastal ecology is limited due, in part, to the high cost of commercial wave gauges. High-cost gauges also limit the scope of coastal wave models and the ability of coastal land managers to design effective restoration, conservation and enhancement projects. To address these limitations, a low-cost do-it-yourself (DIY) wave gauge was constructed using commercial plumbing parts, a pressure sensor, an Arduino^© microcontroller and adapted accessories. Details on gauge construction, coding and an instructional video tutorial are provided. Performance of the DIY gauge was determined by measuring the agreement of raw pressure data recorded by the DIY gauge to a comparable commercial gauge in both a laboratory wave channel study featuring a series of wave tests and in a complementary field test. Agreement of raw pressure data among gauges in the wave channel study was assessed using paired t-tests and by fitting linear models. Field test data agreement was assessed by comparing the total wave field energy recorded by each gauge and by fitting a linear model to recorded raw pressure data. Pressure data agreement between the gauges was excellent in all wave channel tests with mean differences between pressure readings consistently near zero and with 95% of all differences lying within ±63 Pascals (<1 cm static water depth), on average. The greatest variability between readings occurred within tests featuring high-frequency waves, mirroring results reported by others. Still, raw DIY wave gauge data explained, on average, 91% of the variance in raw commercial gauge data in wave channel tests. Field performance testing indicated similar gauge responses with 92% total wave energy agreement. Thus, the DIY wave gauge is a viable alternative to high-cost gauges that could improve the understanding and management of coastal environments.

Diamantidou, E.; Santinelli, G.; Giardino, A.; Stronkhorst, J., and de Vries, S., 2020. An automatic procedure for dune foot position detection: Application to the Dutch coast. Journal of Coastal Research, 36(3), 668–675. Coconut Creek (Florida), ISSN 0749-0208.

Coastal indicators are a useful proxy in coastal zone management to describe the status of a physical system and to assess the effectiveness of possible interventions. They can be used as a basis to implement and evaluate coastal erosion policies, as it is done, for example, in The Netherlands. One often used coastal indicator is the position of the dune foot. In the current definition used in The Netherlands to describe the dune foot position, the actual geometry of the profile is, however, not accounted for, but this is simply based on one reference value for the entire coastline. In the present study, an automatic procedure for the detection of the dune foot position is proposed based on the actual shape of the cross-shore profile and on the evaluation of the first and second derivatives of the cross-shore topography. The methodology is compared to visual observations as well as satellite images for case studies in The Netherlands and Portugal, hence showing that the methodology is generally applicable. The algorithm to derive the dune foot position in a cross-shore profile and the database derived from this study are publicly available.