Coastal Beaches Research Articles

Temporal and spatial variations in metals and arsenic contamination in water, sediment and biota of freshwater, marine and coastal environments after the Fundão dam failure

Temporal and spatial variabilities in concentrations of metals (Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) and metalloid (As) associated with the Fundão dam tailings were evaluated in water, sediment and biota from freshwater (tributary, river, lakes and lagoons), marine and coastal (mangroves and beaches) ecosystems affected by the Mariana dam disaster (southeastern Brazil). In freshwater shrimps and fishes, temporal increases in the concentrations of most elements analyzed were observed. This finding was clearly associated with temporal increases in the concentrations of As and metals observed in both water and sediment. In turn, freshwater plankton showed only a temporal increase in Hg concentration, which was also associated with an increased concentration of this metal in the abiotic matrices. In marine fishes, temporal increases were only observed for Cu, Fe and Pb concentrations. Also, temporal increase was observed for Fe concentration in marine plankton (phytoplankton and zooplankton) and shrimps. Marine phytoplankton also showed a temporal increase in Hg concentration. All these findings were clearly associated with temporal increases in the concentrations of these metals in marine sediments. Mangrove crabs showed temporal increases in Hg and Cd, which were associated with temporal increases in water Hg and sediment Cd concentrations, respectively. In turn, beach crabs displayed temporal increases in Mn and Zn, which were associated with temporal increases in the concentrations of these metals in sediments, especially for Mn. In summary, all environmental matrices evaluated in the present study were shown to be contaminated with metals and metalloid associated with the Fundão dam tailings. Additionally, findings reported in the present study relative to the spatial variabilities observed in the whole aquatic area affected by the Fundão dam failure clearly reinforce the need of incorporating biological diversity in monitoring programs aiming to assess environmental health of aquatic systems, considering that patterns of metals and metalloid contamination levels may vary among taxa.

The Formation of Late Pleistocene and Holocene Sand Dunes on Kikaijima Island, Nansei Islands

Coastal sand dunes dating to the latter part of the late Pleistocene were constructed at substantially lower sea levels on Kikaijima Island. They are preserved because of large-magnitude uplifts ascertained from occurrences of outstanding late Pleistocene and Holocene coral terraces. In addition, because Holocene sand dunes occur close to those of Marine Oxygen Isotope Stage 3 (MIS 3), the island is ideal for examining the environments of the formation of sand dunes, which were constructed under different climatic and sea-level conditions. Distributional and depositional features of sand dunes are clarified, and their chronology is constructed on the basis of tephrochronology, 14C dating, and chronological relationships of the sand dunes with marine terraces of known age. The environments of sand-dune formation on Kikaijima are examined in relation to climatic and sea-level records within regional and global contexts. Nine tephra layers are recognized. These include two widespread tephras, Kikai-Akahoya tephra (K-Ah) and Aira-Tn tephra (AT). The other seven tephras, consisting of fine ash layers, are newly recognized and named Kikaijima-1 tephra (Kj-1) to Kikaijima-7 tephra (Kj-7), of which the upper six, lying between K-Ah and AT, are aged from 13,000 to 30,000 cal BP. Holocene sand dunes began to form at c. 8,000 cal BP before the culmination of maximum Holocene sea-level rise. This is earlier than dune formation on other coasts of the Japanese Islands, where formation was generally after the culmination of maximum Holocene sea-level rise. The earlier formation on Kikaijima Island is probably due to coastal emergence caused by the conspicuous uplifts of Kikaijima and the high production of calcareous beach sands sourced from coral and foraminiferal and other materials. Late Pleistocene sand dunes, predominantly distributed at the southwestern part of Kikaijima Island, were formed in MIS 3. These dunes consist of longitudinal and parallel dunes. The largest longitudinal dunes on the lowest MIS 3 terraces, at the northern area of the southwestern part of Kikaijima Island, were formed in late MIS 3, c. 40 to 32 ka, while small and parallel sand dunes on the upper MIS 3 terraces were formed in early MIS 3. The occurrence and chronology of the Holocene and late Pleistocene sand dunes suggest that their formation on Kikaijima Island is mainly related to the occurrence of coastal sandy beaches during sea-level high stands. Although Holocene sand dunes are related to Holocene high stand, those of MIS 3 are related to high stands during cycles of sea-level fluctuations in MIS 3. The longitudinal landform of the sand dunes recognized in the late MIS 3 suggests that the prevailing winds in MIS 3 were stronger than in the Holocene. This study provides critical data for constructing a chronological framework that integrates various aspects of palaeoenvironments, as well as human interactions and responses in southern Kyushu.

First observations of Least Tern (Sternula antillarum) eggs and other breeding observations on the island of O‘ahu, Hawai‘i

The Least Tern (Sternula antillarum) commonly breeds along coastal beaches and major interior rivers of North America and the Caribbean. Least Terns have been observed in Hawai‘i since the 1970s; however, few breeding attempts have been documented. Nests have been discovered on the northwestern Hawaiian island of Midway Atoll and the southeastern Hawaiian island of Hawai‘i. While nesting is thought to also occur on the islands of O‘ahu and French Frigate Shoals based on observations of juvenile Least Terns, no observations of nests had been recorded for these islands prior to this study. In this paper we describe 2 accounts of discovering Least Tern eggs in the Ki‘i Unit of the James Campbell National Wildlife Refuge on O‘ahu, as well as several observations of breeding behavior in wetlands within the Pearl Harbor region of O‘ahu.

A procedure for comparing the ecological status and transformation measures in an anthropized coastal area

The overall vitality and quality of the coastline can be improved through ecological transformation; ecological status assessment can scientifically guide this modification by putting forward a transformation plan for the coastline. This study took the Shenzhen Bay area between Hong Kong and Shenzhen as the study area to build an index system and combined it with quantitative and qualitative methods by designing the code of data processing, calculation, and analysis through the MATLAB platform, with the goal being to put forward the directions and suggestions for coastline transformation based on the analysis of results. The results and conclusions are as follows: (1) The key aspects of the ecological transformation of the Shenzhen Bay Coastline are water quality, coastal wetland restoration, landscape diversity, beach stability, and infrastructure improvement. (2) Actions to promote these aspects include overall shoreline control of water pollution, cultural landscape implantations, the improvement of existing infrastructure, and the restoration of selected beach sand regions, mangrove wetlands, and eroded shorelines. Suggestion includes the critical support which comes from the public needs for information acquisition and science education, in addition with the policy and management, all should be formulated into the transformation plan. The index system can be applied to other regions at home and abroad, and the results and conclusions based on the index system could also provide criteria for planning the ecological transformation process.

Experimental Study of the Engineering Mechanical Properties of the Foundation Soil for Offshore Wind Power Platforms

Most of the coastal beach zone in the world is rich in wind energy reserves and has great potential for offshore wind power development. However, the sedimentary environment in the coastal area is complex and changeable, and the nature of the foundation soil of offshore wind power platforms is weak and complex, which is quite different from that in the land areas. In order to systematically study the mechanical properties of marine foundation soils, a series of geotechnical tests are carried out on representative undisturbed seabed soils, such as basic laboratory geotechnical tests, bender element tests, undrained triaxial shear tests, and resonance column tests. The test results show that shear wave velocity (Vs) of marine silt and silty clay increases linearly with the buried depth; the stress-strain relationship curves of silty clay and silt present two different modes of development: strain hardening and strain softening, the undrained shear strength (Sd) of the two types of marine soils decreases with the increase of the void ratio (e), and both present a good single correlation. Based on the relationship between Sd and Vs from the laboratory test of disturbed seabed soils, an undrained strength evaluation method of undisturbed seabed soils under the current stratum conditions incorporating in situ shear wave velocity is established. The dynamic shear modulus (G) in the various strain ranges of undisturbed silty clay and silt increases regularly with the buried depth (H). Meanwhile, the maximum dynamic shear modulus (Gmax) linearly increases with the increase of H, whereas the attenuation relationship of G decreases with the increase of H. The prediction method of G based on buried depth is established with high accuracy.

Shoreline Variation Analysis by Cross-Shore Sediment Transport Resulting from Effects of Storm Waves

Kim, T.K.; Jeong, J.H., and Lee, J.L., 2021. Shoreline variation analysis by cross-shore sediment transport resulting from effects of storm waves. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 539–543. Coconut Creek (Florida), ISSN 0749-0208. Coastal beach erosion is affected by not only the wave energy of a storm wave, but also its duration. Therefore, this study analyzes the duration characteristics for different storm wave scenarios using wave data obtained over 40 years; these data were provided by the National Oceanic and Atmospheric Administration (NOAA). Further, the vulnerability of shoreline erosion deduced from the correlation between the cumulative breaking wave energy and observed shoreline variability was discussed. To analyze the duration of storm wave scenarios, we propose dimensionless characteristics for peak wave height per storm wave scenario and a representative mathematical function for storm wave scenarios. Shoreline variability is calculated using the shoreline survey data for Bongpo Beach, located on the eastern coast of South Korea, measured quarterly for nine years. The cumulative breaking wave energy flowing into the beach generally exhibited a linear relationship with the shoreline variability. Therefore, this study suggests a simple method to determine the extent to which the shoreline retreats given the peak wave height of the incoming wave scenario.

IDENTIFIKASI MORFOLOGI DAN KEANEKARAGAMAN KEPITING PADA TIMBUNAN BERBATU DI PANTAI PESISIR MALALAYANG DUA KOTA MANADO

The diversity of crabs in the Malalayang One coast is thought to vary between research locations and limited information on biota that live on rocky, sandy and muddy coastal beaches. Sampling was carried out at low tide at night by capturing directly using a protected hand and for lighting with the help of a flashlight. The collected samples were taken to the Aquaculture Technology Laboratory, Faculty of Fisheries and Marine Sciences, UNSRAT to be identified and for diversity using the Shanon-winer mathematical formula. The results of crabs obtained at five coastal locations on the coast of Malalayang, Manado, with a total of 106 with 7 species, namely Metopograpsus latifrons, Sesarmops impressus, Ocypode kuhlii, Macrophthalmus mareotis depressus, Uca vocans dussumieri, Grapsus Longitarsis and Grapsus albolineatus.Keywords: Crab, Morphology, Diversity, Coastal Ecosystem.

Geochemical fluxes in sandy beach aquifers: Modulation due to major physical stressors, geologic heterogeneity, and nearshore morphology

Coastal beach aquifers are biogeochemically active systems that mediate chemical and material fluxes across the land-sea interface. This paper provides a review of major physical stressors and geologic features that influence flow and solute fate and transport in coastal beach aquifers. We outline current understanding of the interactions between these factors and their associated impacts on water and geochemical fluxes within and across these aquifers. The physical processes that control flow, transport, and the formation and distribution of reactive zones in beach aquifers (e.g., tides, waves, density gradients, precipitation, episodic ocean events, and evaporation) operate across overlapping temporal and spatial scales, and present challenges for measuring and modeling physical flow and biogeochemical processes in coastal groundwater systems. Geologic heterogeneity introduces further complexity by modifying flowpaths, mixing patterns, and rates of biotransformation . Interactions between these physical stressors and geological controls are likely to evolve with changes in sea level, climate variability , human settlement, coastal erosion , and other natural and anthropogenic stresses, providing avenues for scientific exploration into the future role of beach aquifers as chemical mediators between the land and ocean.

Hedonic property prices and coastal beach width

AbstractPrevious research suggests that coastal housing values capitalize the quality of nearby beaches but note potential problems related to measurement errors and reverse causation due to beach replenishment. We offer the first hedonic analysis of communities not engaged in beach replenishment, obviating concern over reverse causation. Statistical evidence supports hedonic specifications that account for proximity to the shoreline, though marginal willingness to pay (WTP) varies with the specification. Using an instrumental variables approach, we find significant downward bias in ordinary least squares estimates of marginal WTP derived from the sale of vacant lots compared to two‐stage least squares estimates on the same vacant lots. Notably, we do not find evidence of the same downward bias in WTP derived from the sale of existing homes.

Detailed hydrogeological and hydrochemical reassessment of the Niger Delta Basin, South-south Nigeria

This review presents a detailed analysis of hydrogeological and hydrochemical conditions of the Niger Delta Basin. Hydrogeologically, the specific capacities recorded from different areas within this Basin vary from 6700 lit/hr/m to 13,500 lit/ hr/m. The water table is very close to the ground surface and varies from 0 to 4 meters. Unconfined groundwater aquifers occur in shallow unconfined aquifers, sands of the coastal beach ridges and river point bars, and sandy islands within the mangrove belt. There is a stable water table fluctuation which characterised the high precipitation zone. The shallow aquifers of Benin Formation are more porous than those in the Deltaic areas. In the southern areas, along the coastal zone, an artesian condition occurs. However, the aquifers are less transmissible with increased depth of the confined aquifer, owing to its more delicate texture. Therefore, more compact, and less permeable, or that there is not enough water in storage. More than half of groundwater sources in the Basin are acidic. Based on mean TDS concentration groundwater, fall in an excellent class for drinking. Groundwater classification based on conductivity showed all the reported findings indicate conductivity ranging from 250-750 μS/cm. Based on cation and anion chemistry, the Niger Delta Basin holds water of relatively acceptable drinking quality. However, the uncontrolled groundwater development, land-use changes, pollution from industrial, municipal, and agricultural effluents pose a threat to groundwater quality protection. Thus, a policy guideline is required to protect groundwater from pollution.

A storm hazard matrix combining coastal flooding and beach erosion

Coastal storms cause widespread damage to property, infrastructure, economic activity, and the environment. Along open sandy coastlines, two of the primary coastal storm hazards are coastal flooding by elevated ocean water levels and beach erosion as the result of storm wave action. At continental margins characterized by a shallow, wide continental shelf, coastal storms are more commonly associated with amplified storm surge and the damaging impacts caused by flooding of low-lying land. In contrast, along margins where the continental shelf is narrow and deep, coastal storm impacts are more often characterized by beach erosion, due to the typically lower magnitude of storm surge but a higher proportion of deepwater wave energy reaching the shoreline. A new Storm Hazard Matrix is presented that integrates these two distinct but inherently linked open coast hazards. The approach is based on the combination of two hazard scales. The first is a ‘coastal flooding hazard scale’ that follows an established framework in which hazards are predominately driven by the vertical increase in ocean water levels during storms and any significant morphological changes caused by the storm are inferred. The second is a storm wave ‘beach erosion hazard scale’ where hazards are predominately determined by the horizontal recession of the sandy beach and dune without necessarily large increases in water levels. The resulting framework comprises a total of sixteen unique combinations of flooding/erosion storm hazard regimes, each potentially requiring different disaster risk reduction approaches. Real-world application of the Storm Hazard Matrix is explored at contrasting coastlines for two major storm events, encompassing an extratropical cyclone that impacted the coastline of southeast Australia in June 2016, and a large hurricane (Hurricane Ivan) that impacted the Gulf Coast of the United States in 2004. The new approach identifies and distinguishes between the severity of localized coastal flooding and/or coastal erosion, and also provides enhanced insight to the nature, magnitude and alongshore variation of coastal storm hazards along the impacted coastline. Within the context of disaster risk reduction, preparedness and operational early warning, implementation of the Storm Hazard Matrix has the potential to deliver robust evaluations of storm hazards spanning a wider variety of both wave-dominated and surge-dominated coasts.

Carbonized rice husk coated solar absorber for clean water generation from seawater with a solar still

ABSTRACT This study demonstrated the generation of clean water from seawater collected at the beach coast in Universiti Malaysia Sabah, Malaysia, with carbonized rice husk coated melamine sponge as solar absorber by a solar still. Melamine sponge was utilized as a seawater transportation medium since its porous structure is excellent in channelling the seawater. Whereas carbonized rice husk was used as the photothermal conversion material for its efficient heat absorption due to its black colour and porous structure. Implementing air gap between the seawater body and solar absorber, and restricted water pathway assisted in localizing heat on the top surface of the solar absorber. Clean water was generated under direct solar radiation during the day at an open space with average solar intensity around 1.1∼1.2 kW/m2 (slightly higher than 1 sun) for about 4 h. Efficiency of the solar absorber was calculated, while the quality of the generated clean water was observed in terms of salinity and pH value. Insulated solar still with carbon-coated sponge showed the highest efficiency at about 54.74%. Salinity of the collected clean water significantly reduced to consumable level which was approximately 55 ppm, and the pH value at about 6.73 where it was within the safe limit of the drinkable water pH.

Calculation Model for Multiple Breaking Waves and Wave-Induced Currents on Very Gentle Beaches

Abstract Multiple wave breaking and wave-recovery processes are typical phenomena of wave motions observed on very gentle coastal beaches and have not been accounted for in previous models for the ...

Pengaruh Media Tanam dan Intensitas Naungan Terhadap Pertumbuhan Bibit Api-Api (Avicennia alba)

Mangrove forests are ecosystems located in tidal areas in coastal areas, beaches, and small islands. The area of ​​mangrove forests is decreasing due to the conversion of mangrove forests into fishponds, plantations, and timber exploitation. Mangrove ecosystem rehabilitation activities need to be carried out through planting. Avicennia alba is a pioneer mangrove species that grows in mangrove swamp habitats on sheltered coastal locations, as well as in the saltier parts of the coastline. The objectives of this research is to analyze the effect of planting media and shade intensity on the seedling growth of Avicennia alba. The study used a two-factor experimental design in a complete randomized design. The first factor is planting media and the second one in shade intensity. The results showed that the shading intensity most influenced the growth of Avicennia alba seedlings. The variables affected include height, diameter, number of leaves, total wet weight, and total dry weight. The treatment combination that gave the best results was A2N0, that means the planting medium in the form of a mixture of mud, sand and compost and without shade (0% shade).
 Keywords: Avicennia alba, growth, photosynthesis, planting media, shade intensity

Assessing the Impact of a Winter Storm on the Beach and Dune Systems and Erosion Mitigation by Plants

The impact of storms on coastal dunes and beaches and the effects they induce in topography and plant communities are natural processes that contribute to maintaining natural coastal dynamics. However, because coasts are often densely populated, these phenomena are perceived as major threats to human property. To protect human assets sustainably, nature-based defenses have emerged as an option. Coastal dunes act as natural buffers that mitigate the extent of erosion and inland flooding, and their resistance depends on the biogeomorphological feedback between the plants and the dunes. This study aimed to evaluate the effect of one winter storm on beach and dune topography and the plant communities, and to explore the effect of plants in mitigating erosion on beaches with different geomorphological features. The effects on plant communities were evaluated by comparing diversity and plant cover before and after the storm. Later, the role of plants in conferring dune resistance against erosion was examined by measuring erosion on the exposed face of the dunes considering plant cover and plant richness. The results did not show significant differences in plant diversity and plant cover between pre-and post-storm conditions, but turnover of species was recorded. The dune building species were not affected but inland species disappeared. Erosion was reduced when the dunes were higher and, furthermore, plant cover was negatively correlated with erosion on these dunes. The results showed a reduced impact of the storm on the plant communities, which is important as it facilitates the recovery of dunes by the dune-building species and protects them in a subsequent storm. The novelty of this study is that: (a) it demonstrates the species-specific role of plants in mitigating dune erosion in field conditions; (b) it shows the interaction between plant-related features and geomorphological variables in promoting dune resistance to erosion, and (c) it explores the immediate effect of a winter storm on the plant community and dune-building species.

RETRACTED ARTICLE: Image recognition of coastal environment and aerobics sports based on remote sensing images based on deep learning

When analyzing the environmental development of coastal areas, the main basis used by researchers for analysis is the data information collected by remote sensing sensors. In the process of research and analysis, experts divided the areas displayed by remote sensing images into three types based on the characteristics of ocean areas, land, and intermediate zones, namely, sea areas, coastal beaches, and land areas. Today, with the continuous development of science and technology, people can choose the most appropriate image research method according to the development characteristics of different regions to better study the spatial distribution and geographic distribution of images. In the current era of development, the level of development of robot services is constantly improving. In order to improve the intelligence of robot service functions, people have begun to study the ability of machines to recognize human activities, and strive to meet the needs of development in all aspects. This article analyzes the characteristics of robot visual action recognition, compares and analyzes three different action representation methods, and uses deep learning related technologies to improve the level of action recognition.

Holocene morpho-sedimentary evolution of Marambaia Barrier Island (SE Brazil)

AbstractBarrier islands are sedimentary bodies susceptible to changes in sediment supply, dominant physical processes, and sea level. The aim of this work was to study the sedimentary processes that established Marambaia Barrier Island (SE Brazil) as an elongated sandy body that created Sepetiba Bay. For this purpose, barrier and back-barrier bay environments were analyzed using high-resolution satellite imagery, geophysical and topographic surveys, surface sediment samples and short cores, and radiocarbon and optically stimulated luminescence (OSL) dating techniques. Seven morpho-sedimentary domains were identified: coastal beach ridges, overland flow features, inter-ridge paleo lagoon, bayside beach ridges, marshlands, dune field and tidal wetlands. The results show that Marambaia Barrier Island evolved throughout the Holocene, first under normal regression conditions during sea-level rise, and then by forced regression as sea level lowered to its present position. Concurrent processes related to longshore drift, onshore transport, reworked barrier deposits, eolian transport, bay circulation, and pedogenesis influenced its morpho-sedimentary evolution. Morphological features such as truncated beach ridges, flying spits, and filled channels attest to the occurrence of alternating periods of erosion and accretion, evincing how the morphology of barrier island systems preserves an important archive of environmental changes.

Environmental Surveillance and Characterization of Antibiotic Resistant Staphylococcus aureus at Coastal Beaches and Rivers on the Island of Hawai'i.

Staphylococcus aureus are human facultative pathogenic bacteria and can be found as contaminants in the environment. The aim of our study was to determine whether methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) isolated from coastal beach and river waters, anchialine pools, sand, and wastewater on the island of Hawaiʻi, Hawaiʻi, are a potential health risk. Samples were collected from three regions on Hawaiʻi Island from July to December 2020 during the COVID-19 pandemic and were characterized using whole-genome sequencing (WGS). From WGS data, multilocus sequence typing (MLST), SCCmec type, antimicrobial resistance genes, virulence factors, and plasmids were identified. Of the 361 samples, 98.1% were positive for Staphylococcus spp. and 7.2% were S. aureus positive (n = 26); nine MRSA and 27 MSSA strains were characterized; multiple isolates were chosen from the same sample in two sand and seven coastal beach water samples. The nine MRSA isolates were multi-drug resistant (6–9 genes) sequence type (ST) 8, clonal complex (CC) 8, SCCmec type IVa (USA300 clone), and were clonally related (0–16 SNP differences), and carried 16–19 virulence factors. The 27 MSSA isolates were grouped into eight CCs and 12 STs. Seventy-eight percent of the MSSA isolates carried 1–5 different antibiotic resistance genes and carried 5–19 virulence factors. We found S. aureus in coastal beach and river waters, anchialine pools, and sand at locations with limited human activity on the island of Hawaiʻi. This may be a public health hazard.

RETRACTED ARTICLE: Influence of coastal beach stability based on interactive VR technology and bookbinding design of city library

This paper first introduces the design and key technologies of the whole interactive VR system, focusing on the principle of the node-based interactive VR system program, the integration of available modules, and the architecture of the plug-in system. It also allows developers to use visualization programs to create scenarios to complete the required design activities. Based on this, this paper uses PSR rough sets and ARIMA model to evaluate the spatial structure strength of beach stability under the combined action of natural and human factors, clarify the potential factors, and to some extent predict the future development trend of L beach. The results of this study illustrate the law of estuarine bank erosion and the theory of ecological stability, which is of great significance to regional wetland safety and beach stability. Finally, by using the methods of literature survey and network survey, this paper selects 13 different first-level public libraries as samples to investigate and study the development of bookbinding mode. There are four characteristics of library bookbinding: personalized intelligent service, interactive three-dimensional service, space reconstruction service, and virtual experience service. At the same time, the paper analyzes the existing problems and points out that it is urgent to strengthen the bookbinding management plan of public libraries and strengthen the service scope and depth of public libraries, so as to improve the necessary functional requirements of public libraries. Moreover, the bookbinding plans of public libraries in different regions are unbalanced and need to be improved. In this paper, the results of the research on the stability of coastal beaches based on interactive VR technology are applied to the bookbinding design of the city library, so as to promote the development of the bookbinding design of the city library.

Decadal shoreline erosion and recovery of beaches in modified and natural estuaries

Sandy beaches in estuaries and bays (BEBs) are common landforms on the coasts of many major cities. They exist under a wide range of settings and their morphology is controlled by their distance from the estuary/bay entrance, exposure to different types of waves (e.g., ocean swells vs locally generated wind waves), proximity to flood-tide delta/shoals, and anthropogenic interventions (e.g., dredging, groynes). Both swell waves propagating into estuaries/bays and locally generated wind waves can erode BEBs. However, more understanding of BEB storm erosion and recovery over decadal timescales is needed, as they typically respond slower than open coast beaches. Here we present decadal shoreline behaviours of nine BEBs from two estuarine systems in SE Australia are presented in this study, using 76 years of aerial imagery (1941–2017). We quantify and compare decadal behaviour between beaches, developing a new typology of BEBs based on shoreline evolution. We identify four decadal behaviours: prograding, quasi-stable, retreating and storm relict – and assess the influence of flood-tide deltas, river mouths, distance from the ocean entrance, and anthropogenic interventions. Swell-exposed BEBs near the entrance are quasi-stable and recover after storms at rates comparable with open coast beaches (<3 years). In contrast, BEBs further from the entrance and those with less swell exposure, have slower recovery timescales (3–15 years) and will only be quasi-stable if storms are sufficiently infrequent. Thus, long-term behaviour is controlled by storm return timescales. Prograding BEBs are typically far from the entrance, where fluvial and tidal processes dominate and erosion events due to wind waves are less pronounced. Whether BEBs recover (quasi-stable), partially recover between storms (retreating) or never recover (storm relict) relates to storm frequency, recovery rates and proximity to sediment sources and sinks (e.g., dredge sites, flood-tide deltas, tidal channels) and anthropogenic interventions. Findings will help to better understand and manage BEB shorelines in major cities.