Typical Equilibrium Beach Profile Models and Their Significances from Different Segments of A Headland-Bay Beach

This study introduces three typical models on equilibrium beach profile, and discusses the application limitations of these models. Then this study examines the selections for applying these models on different coastal segments of a headland-bay beach in west Guangdong, South China, and explores the physical significances of those parameters in the models. The results indicate that：（1） Bodge＇s model is more in line with the equilibrium beach profile of the tangential or transitional segment, whereas Lee＇s model is more consistent with the shadow profile;（2） most of the parameters in three models have clear physical significances in accordance with the actual characteristics of this headland-bay beach; and（3） both the selections for the equilibrium beach profile from different segments and significances of most of the parameters in three models are in essence correlated with the morphodynamic states at various coastal locations.

Wave-dominated,mesotidal headland-bay beach morphodynamic classsfications of the Shuidong Bay in South China

Beach morphodynamic classifications have achieved extensive acceptance in foreign coastal geomorphological studies. Three beaches located in different zones of a headland-bay coast are classified according to a dimensionless fall parameter, a relative tide range parameter and a dimensionless embayment scaling parameter. Synchronous data, including wave, tide, sediment and beach morphology, are respectively collected from the tangential beach, the transitional beach and the shadow beach of the Shuidong Bay during each spring tide for 16 successive months. The research results indicate that （1） the beach in the tangential zone falls between two major categories which are low tide terrace beaches with rips and barred beaches; the beach in the transitional zone exhibits two main types which are low tide bar/rip beaches and barred dissipative beaches; and the beach in the shadow zone mainly mirrors dissipative states with presence or absence of bars; and （2） the sequential changes and differences of beach states in different coastal zones reflect spatial and temporal variabilities of the headland- bay coast, totally meeting the actual measured beach morphology changes, showing that studies on wave- dominated, meso-macrotidal beaches need to consider the influences of the tides. Meanwhile, the research mainly provides a framework about beach state studies, due to different beach states with different erosion patterns, which requires the need to strengthen the researches in this respect, in order to further enrich theoretical basis for a beach topography evolution, beach morphodynamic processes and beach erosion orevention in China.

Application of the Static Headland-Bay Beach Concept to a Sandy Beach: A New Elliptical Model

The headland-bay beach is one of the most common coastal types in the world.Its morphology reflects the changes that occurred during long-term evolution of the sandy coast.Several headland-bay beach models have been proposed to simulate the coastline’s configuration in equilibrium.In this paper,a new elliptical model is proposed,described,and applied.On the east coast of Laizhou Bay in Shandong Province from Longkou Port to Diaolongzui,four typical headland-bay beaches have developed,and four headland-bay beach models are used in this paper to simulate the morphology of these beaches to assess the applicability of each model.The simulation results of the elliptical model verify that it is applicable to the study area.In addition,the elliptical model is easy to use.Through simulation and field investigations,we concluded that most of the coastal segments in this area will remain in an erosion state,and the human activity has a significant impact on the shoreline’s evolution.

Different responses of two adjacent artificial beaches to Typhoon Hato in Zhuhai,China

Major differences in beach erosion between two neighboring artificial beaches Xiangluwan Beach(XL beach)and Meiliwan Beach(ML beach)in Zhuhai,China,were studied after Super Typhoon Hato.In this study,a fully nonlinear Boussinesq wave model(FUNWAVE)-Total Variation Diminishing(TVD)was used to distinguish the main impact factors,their relative contributions,and the hydrodynamic mechanisms underlying the different beach responses.Results show that compared to the ML beach,the main reason for the relatively weak erosion on Xiangluwan(XL)beach was the smaller beach berm height(accounting for approximately 75.9%of the erosion response).Regarding the beach with a higher berm,the stronger wave-induced undertow flow,along with the higher sediment concentration,led to a higher offshore sediment transport flux,resulting in more severe erosion relative to the beach with a smaller berm height.The second most important reason explaining the weak erosion on XL beach was the absence of seawalls(accounting for approximately 17.9%of the erosion response).Wave reflection induced by the seawall could cause higher suspended sediment concentration,resulting in a toe scouring near the seawall.The offshore submerged breakwater protected XL beach slightly(accounting for approximately 6.1%of the erosion response).Due to the higher water level induced by storm surge,most of the wave energy could penetrate through the submerged breakwater.The effect of the larger berm width of XL beach was negligible.Compared to the beach with a larger berm width,the erosion/deposition regions in the beach with a narrower berm width showed shoreward migration,without significant changes in the erosion/deposition extent.Despite of this,the larger berm width could reduce the wave energy reaching the shoreline.This study of the storm stability of artificial beaches may be applied to beach restoration design.

Gravity Fault Subsidence and Beach Ridges Progradation in Quinta-Cassino (RS) Coastal Plain, Brazil

Ground penetrating radar (GPR) surveys have being applied to investigate very near-surface stratification of sedimentary units in coastal plains and to define their depositional conditions. This paper presents, however, low-frequency GPR survey to investigate fault-related depositional systems at greater depths. The Quinta-Cassino area in the Rio Grande do Sul Coastal Plain (RGSCP, Brazil) shows a wide strandplain that is made off by very long, continuous, and linear geomorphic features (beach ridges). This strandplain extends for ~70 km southward. The beach ridges show low-angle truncations against the Quinta escarpment, and also truncations in the strandplain. The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;previous model assumes that no deformational episode occurred in RGSCP. The geophysical and geological surveys carried out in this area showed the existence of listric fault controlling the beach ridges in the escarpments and hanging-wall blocks. The radargrams could distinguish Pleistocene basement unit anticlockwise rotation, thickening of beach ridges radarfacies close to listric normal faults, and horst structures. These deformational features indicate that the extensional zone of a large-scale gravity-driven structure controlled the mechanical subsidence, the Holocene sedimentation and its stratigraphic and geomorphic features in the Quinta-Cassino area to build up an asymmetric delta. The results point to a new approach in dealing with RGSCP Holocene evolution.

Assessment and Application of Beach Quality Based on Analytic Hierarchy Process in Yangkou Beach, Qingdao

The whole-beach quality assessment is the basis of building and preserving beautiful beaches.The beach quality assessment index system and assessment standard have been established based on the attributes of beaches(including the width,slope,landform,and types),sorting coefficient,and softness degree of surface sediment.The assessment weight of each index for quality evaluation was analyzed using the analytic hierarchy process,and comprehensive scores of selected beach profiles were calculated in accordance with the light assessment standard.A beach quality evaluation model based on index weight and scores was established in this paper.The factors of 12 profiles of Yangkou Beach in Qingdao City were surveyed to carry out a quality assessment,and the comprehensive scores of each profile were calculated in accordance with the evaluation model.The results showed that the quality of Yangkou Beach can be divided into four ratings:excellent,good,medium,and poor.The excellent-quality area includes a wide and flat dry beach zone and soft,flat,and clean intertidal and subtidal zones covered with well-sorted fine sand,and leisure sports,such as volleyball,running,and swimming,are suitable for tourists.The good-quality area features a slightly narrow and dry beach zone,moderately soft and uneven intertidal and subtidal zones covered with fine sand and a small tidal gully,and a small amount of foreign matter;leisure sports,such as walking and running,are suitable for tourists.This study recommends the building of fixed drainage ditches or underground culverts to reduce the tidal gully.The medium-quality area consisted of a narrow and dry beach zone,moderately soft and uneven intertidal and subtidal zones covered by poorly sorted medium sand,a tide ditch,and a small amount of foreign matter.In this area,walking is suitable for tourists.Sand should be supplemented in the intertidal zone.The poor-quality area contained a very narrow and dry beach zone covered with poor-sorted gravel,a very chaotic intertidal zone with a considerable amount of foreign matters,such as bricks and rocks,wide tidal ditches,and an uneven subtidal zone with some reefs;leisure sports are unsuitable here.Thus,foreign matter and reefs should be removed,and the dry beach zone should be supplemented with sand.Therefore,the beach quality assessment is a very useful tool for building beautiful beaches.

Morphodynamic response of an embayed beach to different typhoon events with varying intensities

Beach erosion has occurred globally in recent decades due to frequent and severe storms.Dongsha beach,located in Zhujiajian Island,Zhejiang Province,China,is a typical embayed sandy beach.This study focused on the morphodynamic response of Dongsha beach to typhoon events,based on beach topographies and surficial sediment characteristics acquired before and after four typhoon events with varying intensities.The four typhoons had different effects on the topography and sediment characteristics of Dongsha beach.Typhoons Ampil and Danas caused the largest(-51.72 m3/m)and the smallest erosion(-8.01 m3/m),respectively.Remarkable alongshore patterns of beach profile volumetric changes were found after the four typhoon events,with more erosion in the southern and central parts of the beach and few changes in the northern part.Grain size coarsening and poor sorting were the main sediment patterns on the beach influenced by different typhoons.Typhoons that occurred in the same year after another typhoon enhanced the effect of the previous typhoon on sediment coarsening and sorting variability,but this cumulative effect was not found between typhoons that occurred during different years.A comparison of the collected data revealed that the topographic state of the beach before the typhoon,typhoon characteristics,and tidal conditions were possible reasons for the difference in the responses of Dongsha beach to typhoon events.More severe beach erosion was caused by typhoons with higher intensity levels and longer durations,and high tide levels during typhoons can determine the upper limit of the beach profile erosion site.Taken together,these results can be used to improve beach management for storm prevention.

Variation in cross-shore wind speeds influenced by the morphology of nourished beach

The cross-shore variation in wind speeds influenced by beach nourishment,especially the dramatic changes at the nourished berm,is important for understanding the aeolian sand transport processes that occur after beach nourishment,which will contribute to better beach nourishment project design on windy coasts.In this paper,the influencing factors and potential mechanism of wind speed variation at the edge of a nourished berm were studied.Field observations,together with the Duna model,were used to study the cross-shore wind speed distribution for different nourishment schemes.The results show that the nourished berm elevation and beachface slope are the main factors controlling the increase in wind speed at the berm edge.When the upper beach slope is constant,the wind speed at the berm edge has a positive linear correlation with the berm elevation.When the berm elevation remains constant,the wind speed at the berm edge is also proportional to the upper beach slope.Considering the coupling effects of nourished berm elevation and beachface slope,a model for predicting the wind speed amplification rate at the nourished berm edge was established,and the underlying coupling mechanism was illustrated.

Analysis of wave shoaling and shore-breakers on a low tide terrace beach based on in-situ measurements at Xisha Bay on South China coast

Low tide terrace beach is a main beach type along South China coasts with strong tidal actions.How strong tides affect wave transformations on low tide terrace beach still remains unclear.In this study,in-situ measurements are conducted on the low terrace beach at Xisha Bay to provide quantitative descriptions of wave shoaling and shore-breaker phenomena under the tidal effects.It is found that wave breaking is unsaturated on the low tide terrace beach at Xisha Bay.Magnitudes of wave skewness and asymmetry increase as wave shoals and achieve the maximum value at the shore-breaker,and then decrease rapidly.Mean energy dissipation rates of shore-breakers are tide-modulated since the bottom slope changes at the shoreward boundary of wave propagation in a tidal cycle.The remaining wave energy flux at the initialization of the shore-breaker is 1%–12%of offshore wave energy flux,and the energy flux ratio decreases with increasing offshore wave heights.Wave attenuation at shore-breakers can be estimated directly from offshore wave conditions based on findings in this study,favoring designs of seawalls or beach nourishment projects.Field datasets on wave transformations can also be used for verifications of wave numerical models.

Dynamic geomorphology and storm response characteristics of the promontory-straight beach-a case of Gulei Beach, Fujian

As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for studying the dynamic geomorphological processes and storm response of promontory-straight coasts.This study is based on three years of topographic data and remote sensing imagery of Gulei Beach and uses topographic profile morphology,single width erosion-accretion and mean change,combined with the Coastsat model to quantify the seasonal and interannual variability and storm response of the beach and to explain the evolution of shoreline change and beach dynamics geomorphology in the last decade.Gulei Beach has been in a state of overall erosion and local accretion for a long time,with relatively obvious cyclical changes;seasonal changes are also obvious,which are mainly characterized by summer accretion and winter erosion,with accretion at the top of the bay and accretion and erosion on the north and south sides of the bay corner,respectively;the seasonal erosion-accretion volume of the beach profile ranges from-80 m3/m to 95.52 m3/m,and the interannual erosion-accretion volume ranges from-69.09 m3/m to 87.31 m3/m.The response of beaches to typhoons with different paths varies greatly depending on the length,slope,orientation and scale of beach development.The large and gently developing Futou beach is less responsive to storms,while the less developed headlands in the southern Gulei Peninsula are more susceptible to disturbance by external factors and respond more strongly to typhoons.Storm distance is more influential than storm intensity.Under the influence of human activities,obvious erosion hotspots develop during normal weather,but storm processes produce redistribution of beach material patterns,and erosion hotspots disappear after storms.The results of this study enrich the theory of beach dynamics geomorphology and provide technical support for disaster prevention and mitigation,as well as ecological restoration of coastal zones.

Using video imagery to reconstruct the 3D intertidal terrain along a beach with multiple cusps

A high-frequency,high-resolution shore-based video monitoring system(VMS)was installed on a macrotidal(tidal amplitude>4 m)beach with multiple cusps along the Quanzhou coast,China.Herein,we propose a video imagery-based method that is coupled with waterline and water level observations to reconstruct the terrain of the intertidal zone over one tidal cycle.Furthermore,the beach cusp system(BCS)was precisely processed and embedded into the digital elevation model(DEM)to more effectively express the microrelief and detailed characteristics of the intertidal zone.During a field experiment conducted in January 2022,the reconstructed DEM was deemed satisfactory.The DEM was verified by RTK-GPS and had an average vertical root mean square error along corresponding RTK-GPS-derived intertidal profiles and corresponding BCS points of 0.134 m and 0.065 m,respectively.The results suggest that VMSs are an effective tool for investigating coastal geomorphic processes.

Quantitative Analysis of the Sized Ranged Plastic Debris on Beach Shoreline along the Limbe Coastline, Cameroon

In recent years, increased interest in investigating the accumulation of sized ranged plastic debris has been observed on beaches along coastlines. The abundance and distribution of the 4M’s sized class plastic debris were quantitatively assessed on five sandy beaches, in Cameroon. Duplicates of 2 × 2 m (4 m2) quadrants were sampled in each beach/month with a total of 80 quadrants. Collected plastic samples were washed, sieved and dried. Particles of size, ≥2 mm, were sorted and measured using a 30 cm ruler, and converted to mm. Overall, 12,822 particles by number (530.59 g) with a mean abundance of 40.07 items/m2 (1.66 g/m2) plastic debris was recorded. ANOVA (p = 0.05) shows a linear relationship between the meso- and micro-sized classes with significantly higher abundance recorded in LDB sites. The highest abundance by weight was recorded in August and June numerically. 80% of the plastic particles were between the size range, of 5 - 20 mm by number and 6 - 100 mm by weight. Moreover, in all beaches micro-sized class plastics were dominated by number 42.40% with fragmented debris dominant, in number/weight, 54.86% (25.69%) while meso-sized class plastics were 29.28% dominated by weight, with fragmented debris type, the most prevalence in number and weight as 46.11% (26.18%). On average, color and shape fractions revealed, colored and irregularly shaped plastics were dominant with an abundance of 80.45 ± 18.17 items/m2 (2.58 ± 0.68 g/m2) and 47.24 ± 20.40 items/m2 (1.39 ± 0.66 g/m2). Finally, the 0.0001 g plastic debris was dominant with a concentration, of 33.68 ± 7.23 items/m2. The intense use of beaches for recreation and poor waste disposal has increased the potential for plastic contamination.

Nourishment and disaster mitigation efficiency of feeding sand on the dry section of a dissipative beach

To explore the nourishment effect and disaster reduction efficiency of a fully dissipative dry beach under the impact of storms,this paper uses the measured topography and hydrodynamic data to establish a one-dimensional numerical model of the XBeach beach profile.By numerically modeling the change in the nourished profile for different dry beach widths under normal waves and storm conditions and the recovery process of the profile after the storm,the degree of response in dry beach nourishment for the fully dissipative beach is analyzed.The results show that under normal wave conditions,the response of the nourished dry beach is obvious.Sediment on the dry beach erodes heavily,and the shoreline moves landward over a long distance.With the increase in the width and size of the dry beach,the wave height at the bottom of the backshore profile decreases,the wave height attenuation rate increases continuously,and the wave elimination effect is remarkable.When the storm incident wave intensifies,the wave height attenuation rate of the nourished dry beach decreases,indicating that the smaller the storm intensity is,the more significant the wave reduction effect of the nourished dry beach is.At the same time,different profile arrangements of nourished dry beaches suffer from different degrees of erosion under storm conditions,with significant changes in profile morphology.With intensified storm action,the intensity of sediment erosion in the nourished dry beach increases,the nourishment is weakened,and the recovery effect of the profile after the storm is not obvious.The results of the numerical modeling highlight that the dry beach nourishment method can resist storms to a certain extent,but the overall effect is relatively limited.

Sediment source-to-sink process variations of sandy-muddy transitional beaches and their morphological indications

The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment source-to-sink process variations of such beaches and their morphological indications.The results show that the clay mineral assemblages of these SMT-Beaches mainly comprise of almost equal illite(~30%),kaolinite(~28%),chlorite(~22%),and smectite(~20%)contents.From the surrounding mountain rivers to the SMT-Beaches,clay mineral assemblages show distinct spatial changes characterized by a large decrease(~40%)in kaolinite,whereas the other three clay minerals present relative increases,especially clear for smectite.The muddy sediment sources of SMT-Beaches inferred from the clay mineralogy are mainly derived from nearby mountain rivers coupled with long-distance transport and penetration of the Changjiang River.The sandy sediments of these beaches are predominantly sourced from nearby mountain rivers,the weathering products of surrounding rocks in both mainland and island environments,and erosion of the“Old Red Sand”and“Red Soil Platform”.However,the sandy sediment sources of the SMT-Beaches are largely reduced because of the remarkable decrease in the river fluvial supply associated with intensive human activities such as dam construction and coastal reclamation.Subsequently,the sandy sections of SMT-Beaches present clear erosion and have revealed by both time series remote sensing images and a compilation of published literature.In contrast,the muddy sediment supply of SMT-Beaches is temporarily stable and relatively constant,resulting in the landward migration of the mudflats with relative transgression or accumulation.These findings highlight that the natural evolution processes of SMT-Beaches have been greatly reshaped by intensive human activities.

The Probable Cause for Nesting Pattern of Olive Ridley (Lepidochelys olivacea) at Ramnagar Beach, North East Coast of Andaman Island, India

The nesting behaviour of sea turtles remains a subject to study, due to their enigmatic pattern of seasonal breeding activities. Over a period of time, several reports have been made in this context associated with the nesting behaviour of the Olive Ridley turtles. In the present study, characteristics of the breeding beach and nesting pattern of Olive Ridley (Lepidochelys olivacea) at Ramnagar along N-E coast of Andaman Islands were investigated, during the nesting periods 2016-2017. The study area hosts Olive Ridley, the dominant sea turtles with more than 300 individuals nesting each year. For this study, the number of sea turtles visited, nested, the sediment characters, salinity, and temperature were taken. The exposed sandy nesting beach characteristics are prone to varying degrees of morphological changes every day. The results depict that even though similar grain size (Coarse Sand to Fine Sand and Very well sorted to Poorly Sorted), with an ambient incubating temperature, pH and salinity with wide nesting area, the selective nesting in the particular location of the beach identified because of comfortable energy conditions in the waters (1.5 m/s) favours the female turtles to reach the beach at the preferable site of Ramnagar and nest.

Maredamare 2023:The international beachwear show

A three-day show entirely dedicated to beachwear and resortwear.From July 22 to 24,the sixteenth edition of Maredamare,the international trade show organized and promoted by Underbeach,will be held in the splendid Fortezza da Basso in Florence,Italy,previewing more than two hundred and fifty beachwear collections for summer 2024.Indoor and outdoor events,fashion shows,the presentation of new trends and an area dedicated to sustainability will be on the program.

Maredamare unveils beachwear trends for summer 2024

Maredamare,the international beach­wear fashion show to be held in Florence July 22-24,unveils a preview of the four major trend themes that will character­ize summer 2024.The style directions have been fine-tuned with a great deal of forecasting work shared with the leading brands of the next edition.Sporty,retro,luminescent and artistic.

2011-2015年东洞庭湖洲滩典型植物群落样方调查数据集

固定样地调查通过长期数据的积累和精准的时空对比获取生态系统动态特征,为长期的生态系统研究提供了坚实的基础。洞庭湖湿地生态系统观测研究站按中国生态系统研究网络(Chinese Ecosystem Research Network,CERN)统一的监测规范,对洞庭湖水文情势变化下,湿地生态系统中典型洲滩植被的物种组成和群落特征等指标进行长期定位监测。通过东洞庭湖三种典型湿地植物群落(苔草,南荻和水蓼)长期监测样地的数据进行加工处理,获得2011-2015年洞庭湖洲滩植物群落长期监测数据集。本数据集包含有植物种名、拉丁名、株(丛)数(株或丛/样方)、叶层平均高度(cm)、生殖枝平均高度(cm)、盖度(%)、物候期、优势种、植物种数、密度(株或丛/m~2)、优势种叶层高度(cm)、优势种生殖枝高度(cm)、总盖度(%)、地上绿色部分总干重(g/m~2),共14个指标,同时附有完整的背景信息。本数据集实行全过程数据质量控制,并由专家审核验证,确保数据时空上的相对一致和准确可靠。本数据集可以为探究洞庭湖水文情势下,洲滩湿地生态系统过程和演替趋势提供本底资料,为洞庭湖植被的遥感监测、生物多样性保护和湿地生态修复及适应性管理等提供数据支撑。

2011-2015年洞庭湖洲滩群落植物生态型、生活型和生长型组成数据集

植物群落结构与环境的关系可以通过研究植物生活型和生态型进行深入的解析,同时植物生活型是研究植物群落的发生、发展及演替规律的重要内容。中国科学院洞庭湖湿地生态系统观测研究站按中国生态系统研究网络(CERN)监测指标体系,在洞庭湖周期性水文变化情势下,对洞庭湖湿地洲滩典型植物群落类型的物种组成进行长期定位监测。通过专家对洞庭湖湿地3个典型植物群落(苔草、南荻和水蓼)的长期监测数据集进行验证,确保数据的准确性,然后进行分类处理,得到洞庭湖洲滩2011-2015年植物群落植物生活型、生长型和生态型数据集。本数据集包含有植物种名、拉丁名、生活型、生长型、光生态型、水分生态型、土壤pH值生态型、淤积生态型,共8个指标,同时提供了完整的样地信息和样地管理记录,为数据的科学利用提供了空间和时间上的背景信息。本数据集为分析洞庭湖湿地洲滩植被群落生态型和生活型组成,植物群落与环境的相关提供了数据支撑,是深入研究洞庭湖湿地植物被演替的重要参考依据。

鄂尔多斯盆地南缘麟游-淳化地区平凉组礁滩体沉积特征及分布预测

鄂尔多斯盆地南缘平凉期发育规模生物礁滩型储层,目前对该区的研究主要集中在礁滩体的类型、成因、区域演化等方面,而对礁滩体的地球物理预测尚未开展系统研究。为了提高礁滩体的预测精度,建立礁滩体储层地震预测方法,通过野外露头实地踏勘,结合岩心及分析测试等资料,对镶边台地高能环境下的生物礁滩发育特征进行研究。通过已知井的井震响应特征,建立礁滩体正演模型,同时开展流体活动性、地震纹理属性分析,形成研究区礁滩体储层的地震预测方法。结果表明:鄂尔多斯盆地南缘平凉组主要发育碳酸盐岩台地边缘-浅水陆棚沉积体系;礁滩体主要分布于台地边缘亚相,多期叠置;高亮体和纹理属性对礁滩体的预测效果最好,2种方法的联合应用大大提高了礁滩体预测精度。研究成果为台缘带礁滩体平面分布规律预测和鄂尔多斯盆地南缘平凉组礁滩体的勘探开发奠定基础。