Beach Protection Research Articles

Investigations-based results on the hydrographic conditions with special reference to the tourist bathing areas of the protected Romanian littoral

The aim of the present work is related to the new hydrographic conditions within newly developed coastal areas through coastal protection measures extension. The study also seeks to assess the impact on the touristic bathing areas and its safety. The new bathymetry, induced by the sediment size, together with currents propagation into the bathing areas adjacent to the newly arranged beach areas were subject of Conductivity Temperature and depth profiler (CTD) and Acoustic Doppler Current Profiler (ADCP) measurements in relation to the summer waves regime and sea level variations. Several experiments habitually conducted during the summer period were considered; the experiments are related to the marine hazards associated to the swimming areas, such as seasonal storm-inducing currents and the propagation of the rip currents in the nearshore, but also to the specific marine currents setups around beach protection groins and longitudinal breakwater, the influence of vertical water movements, including up-welling and specific intensifications in the periods with complex stormy waves.

Physical model analysis of stability coefficient for tetrapod innovation

Beach protection is vital to reduce the damage to shorelines and coastal areas; one of the artificial protections that can be utilized is the tetrapod. However, much damage occurred when using a traditional tetrapod due to the lack of stability coefficient (KD). Therefore, this research aims to increase the stability coefficient by providing minor modifications to the cape of the tetrapod, such as round-caped or cube-caped. The modification seeks to hold the drag force from the wave and offer a good interlocking in between the tetrapod. This research applied physical model test research using a breakwater model made from the proposed innovative tetrapod with numerous variations in dimensions and layers simulated with several scenarios. The analysis was carried out by graphing the relationship between the parameters of the measurement results and the relationship between dimensionless parameters, such as wave steepness H/gT2, and other essential parameters, such as the KD stability number and the level of damage in %. The result shows that the modified and innovative tetrapod has a more excellent KD value than the conventional tetrapod. In addition, the innovative tetrapod with the cube-shaped has a recommended KD value greater than the round shape. This means that for the modified tetrapod structure and the same level of security, the required weight of the tetrapod with the cube cap will be lighter than the tetrapod with the round cap. These findings have significant practical implications for coastal protection and engineering, potentially leading to more efficient and cost-effective solutions.

Shore ice control on coastal geomorphic evolution in cold regions

Shore ice is a common feature on cold climate coasts, which are abundant in mid- and high-latitude regions, however it is understudied. Previous research has reported both beach protection and erosion as potential impacts from shore ice presence. Altered ice dynamics resulting from a changing climate are likely to intensify these impacts. To address this discrepancy and improve future coastal change predictions we conducted the first combined field, laboratory and modeling study of shore-ice processes and impacts. Beach and nearshore morphology mapping, experiments with a novel cryogenic wave tank, and 3D coastal evolution modeling revealed that shore ice protected the beach from storms, but scoured the nearshore at the ice edge and transported sediment offshore, likely past the depth of closure. This resulted in enhanced beach erosion during the ice-free and non-storm season, countering the protective benefit from the ice. This study indicates that shore ice plays an important and likely evolving role in geomorphic evolution along cold climate coasts.

Assessing the dredging vibrational effects on surrounding structures: The case of port nourishment in Bari

The paper presents a study on the dredging vibrational effects, for nourishment purpose, on the existing structures surrounding the worksite. Nourishment is a common operation when beach (or coasts, or ports) protection is required, allowing to reduce far-field impacts of coastal structures and improve navigability. Nourishment is then performed to reshape underwater land, and it is usually practiced by locating in the zones in which is required, soil coming from nearby areas. This latter is often obtained by a dredging process, in which the phases of excavation, transportation and soil placement are carried out. From the structural point of view, of interest is the excavation phase, which is usually performed in the water environment by a ship equipped with a dredge that mines the seabed, generating a new source of vibrations for the existing structures facing the working area. The aim of this paper is to assess the effects of vibrations induced by dredging operations, by taking as reference the recently performed nourishment in the port of Bari, Southern Italy. To this scope, an existing structure was selected and identified as sentry building, considering its extreme proximity to the worksite. Hence, a structural monitoring was performed, by investigating the behaviour of the structure before, during and after the dredging. Three main controls were carried out within the monitoring campaign: (a) check of the vibration levels and comparison with thresholds provided by the current Italian prescriptions for human comfort and structural damages; (b) operational modal analysis to assess the possible variations of the structural behaviour during dredging; (c) calibration of a numerical model to simulate the structural behaviour of the sentry building and to derive unknown geometrical and mechanical parameters. A full description of the reference building (characterized by a certain irregularity degree) and all the monitoring phases are reported throughout the manuscript. The results show that, over the monitoring period, the dredging vibration levels never exceeded the thresholds provided by code provisions, and subsequently, the sentry building did not report structural damages, as confirmed by the continuous control of dynamic parameters from experimental and numerical models. In addition, the contents of the paper show the paramount importance of the structural health monitoring, and the experience herein reported can inspire the management of buildings under particular actions like the ones herein investigated.

Conservation efforts mitigate effects of human disturbance on ghost crab (Ocypode macrocera) abundance and behavior on a sandy beach in Kuakata, Bangladesh

Protected areas play a crucial role in promoting and conserving species by providing a sanctuary for wildlife and natural habitats. In coastal regions, safeguarding measures become even more significant due to the unique challenges posed by anthropogenic activities. This study focuses on the impact of human activities on beach-dwelling biota, specifically the ghost crab (Ocypode macrocera), and highlights the importance of establishing protected areas to safeguard biodiversity and counteract negative impacts on coastal ecosystems. The study was conducted in Kuakata, the coastal region in Bangladesh, known for its ghost crab population. By comparing protected with non-protected beaches, the study examines the effects of protection status on ghost crab abundance and burrow characteristics. Field observations and data collection reveal that protected beaches harbor a greater abundance of ghost crabs compared to non-protected beaches. However, while protection status significantly improves crab abundance, it does not necessarily increase the mean burrow opening size. Interestingly, protected areas show a higher number of small burrow sizes, indicating that protected beaches not only act as feeding grounds but also serve as breeding and nursery grounds for ghost crabs. These findings illustrate the multifaceted role protected areas play in supporting the entire life cycle of ghost crabs, and underscore the importance of preserving these habitats for the species' long-term survival. It highlights the importance of effective management and conservation measures to preserve the health and integrity of coastal ecosystems. By establishing and managing protected areas appropriately, we can ensure the continued existence and viability of these invaluable habitats. Specific human activities that harm coastal biodiversity can be identified to develop targeted conservation strategies. Through this study, such strategies can be developed which may include measures like restricting beach access during breeding season or implementing sustainable tourism practices to lessen the impact.

Observed beach nourishment development in a semi-enclosed coastal embayment

Beaches are important coastal features that provide vital ecosystem services; however, these systems are threatened by coastal erosion, sea-level rise, and coastal squeeze. Beach nourishments are a commonly applied coastal protection measure to mitigate erosion and flood risks while maintaining or enhancing recreational values. Nourishments vary in scale from mega-nourishments to small-scale nourishments, where the latter has typically been less studied due to the limited resources for monitoring. Meanwhile, with rising sea levels, the implementation of small-scale nourishments is expected to increase, and there is a need for more knowledge about the morphological evolution and technical lifetime of these interventions. In this study, the morphological responses of small-scale beach nourishment (total volume 20,000 m3 which amounts to 30 m3 added per m alongshore) are observed and quantified over various timescales, considering the initial adjustment, long-term development, and event-driven response. The investigated nourishment is implemented in a partly sheltered coastal embayment in the semi-enclosed Baltic Sea, which has a complex interaction between waves and water levels. Furthermore, the beach is surrounded by hard structures, a rock revetment at the back, and a harbor mole and a groin, influencing the longshore and cross-shore sediment transport. The results show that substantial reduction in subaerial volume can be attributed to specific events. In addition, we observed considerable spatial variation in the sediment re-distribution induced by hard structures and variability in the nearshore bathymetry. The lifetime of the beach nourishment is just over two years. The nourished material remains in the system at the end of the lifetime but is not available for beach recovery. Still, the added subaerial volume has eroded at the midsection, and the protective beach width has been reduced, leaving the rock revetment exposed with reduced protection for the hinterland. The energy conditions at the site are highly episodic, which impacts morphological evolution, and observations indicate that the development is event-driven.

Incipient Motion of Single Shells under Currents in Flume Experiments

Understanding the motion thresholds of shells is important, as shell motion allows the analysis of beach profiles, prevents excessive erosion of the coastline, and helps to resource the use of discarded shells, providing new ideas for the protection of beaches. In this study, the orientational motions and motion thresholds of two types of typical molluscan shells, bivalve and gastropod shells, were investigated by means of flume experiments. The final orientations with the statistically highest number of occurrences during the orientational motions of each shell were used as the initial orientations for the respective threshold flow velocity measurements. The critical Shields parameter and the incipient mean velocity of the flow were used to represent the critical threshold of the motion. The critical Shields parameters for bivalve shells in the convex upward position were overall higher on average than those for gastropod shells. The experimental data showed that the incipient mean flow velocities of bivalve shells in the convex upward position were about 1.4–2.8 times larger than those in the convex downward position. The incipient mean velocity data were regressed to obtain the motion threshold equations applicable to bivalve shells in the convex upward and convex downward positions as well as gastropod shells under different final orientations.

Study of the effect of spur dikes on beach protection based on physical model experiment

The Qiantang River is a typical strong tide estuary, the world-famous tidal bore have huge turbulent energy and causes damage to the sea wall. Spur dike is an important engineering to prevent the seawall foundation from tidal bore. But the tidal bore occurs at the low tide level, strong turbulence, high flow velocity, water level rises sharply. The spur dike height, length, inclination angle need to be determined by physical model according to the specific bore dynamic conditions. In the tests, the fixed-bed model was used to study the tidal current velocity reduction rate and region, the falling current circulation characteristics in dike field. The movable-bed model test is used to study the effect of each test on protecting the beach. This physical model study reveals the rule of spur dike influence on tidal bore dynamics so the effect of spur dike on protecting the beach is clear.

Evaluating barrier beach protection with numerical modelling. A practical case

Embryonic dunes, continuous dunes and classical beach nourishment are tested as soft coastal protection measures in the vulnerable Trabucador barrier beach located in the NW Mediterranean Sea against different storm conditions. The beach was impacted by severe breaching events during past storms. Evaluation of the performance of the dunes and nourishment as coastal protection measures for the barrier beach is carried out using XBeach model for three different storm events: Storm Isaak being a mid-tier double peak storm, Storm Filomena a typical larger storm of the region and Storm Gloria the largest ever storm to hit the region, with 7, 12 and 60 years of return period respectively. The model showed embryonic dunes and shoreface nourishment systems greatly protect the beach against Storm Isaak and Storm Filomena but did not withstand Storm Gloria considering it being almost 1.5 times larger than the second-highest storm in terms of significant wave height. The study aids in assessing the effectiveness of various mitigation actions for barrier beaches, with the aim of implementing them in practical field applications.

Biomonitoring of microplastics, anthropogenic microfibres and glass retroreflective beads by marine macroalgae

Microplastics and other microscopic debris are a concern in the coastal environment but measurements in the water column and sediment are often problematic and rely on non-standardised and highly variable methodologies. To this end, we explore the potential of different species of temperate-cold marine macroalgae as passive biomonitors of anthropogenic microparticles at three contrasting locations in southwest England. Specifically, fronds from samples of fucoids and Ulva lactuca (n = 9 in total, and three from each location) have been sectioned and analysed directly under a microscope and anthropogenic microparticles counted and subsequently characterised for chemical composition. Microparticles were heterogeneously distributed throughout sections from the same sample. However, on a dry weight basis, combined microparticle concentrations for each sample ranged from about 7.5 g-1 to 110 g−1, and from about 0.2 cm−2 to 0.9 cm−2, and for a given species were higher in samples from a semi-enclosed harbour and urban beach than in samples from a protected beach facing the open sea. These values compare with published concentrations of microplastics and microfibres reported for the regional water column on the order of 0.1 m-3. Most particles were cellulosic (e.g., rayon) and petroleum-based (mainly polyester and polyethylene terephthalate) fibres but plastic fragments were also present on most samples. Glass retroreflective beads derived from road markings were also present at up to 18 g−1 on fucoids from the urban beach because of its proximity to a stormwater effluent. Most microparticles were adhered to the smooth parts of the macroalgal surface but some displayed wrapping around edges and creases or entrapment by appendages. The practical and environmental implications of macroalgae passively capturing significant quantities of anthropogenic microparticles are discussed.

Eko-kejuruteraan dalam Penerapan Pertahanan Pantai berasaskan Alam Semula Jadi

Climate change increases the threat of erosion and flooding along coastlines around the world. Engineering technologies are response to protecting coastal communities and related infrastructure becoming increasingly unsustainable in economic and ecological contexts. This issue has led proposal to restore natural habitats, such as sand shoals, saltwater swamp areas, mangroves, seaweed, coral reefs, and shellfish, to provide coastal protection in lieu of or to complement artificial structures. Often coastal management is faced with eroded coastal problems which require decision on the most suitable mitigation option to implement. In this short review article, the application of eco-engineering in nature-based coastal defense is discussed. The obstacle in taking on the naturebased coastal defences is because of the rigorous assessment of their effectiveness compared to artificial protection structures. The assessment of the latest evidence for the effectiveness of nature-based beach protection versus artificial beach protection and future research needs are discussed in this review. Future projects should evaluate the habitat created or restored for coastal defence for its cost-effectiveness compared to artificial structures under the same environmental conditions. A cost-benefit analysis should consider all ecosystem services provided by nature-based or artificial structures in addition to coastal protection. Research among scientists, coastal managers, and engineers are needed to facilitate the experiments needed to test the value of this coastal protection scheme and to support its use as an alternative to artificial structures. This research is urgently needed because the rapidly changing climate requires new and innovative solutions to reduce the vulnerability of coastal communities.

Numerical construction tests to assess the feasibility of placement grids for Cubipod Homogeneous Low-Crested Structures

Placement grid design is a key phase when constructing armor layers in mound breakwaters. Homogeneous Low-Crested Structures (HLCS) are low-crested structures designed as artificial reefs for marine colonization, coral reef regeneration and beach protection. The placement grid affects the construction feasibility, hydraulic stability and wave transmission of HLCS. This study presents a numerical methodology to simulate a realistic placement procedure for armor units during the construction of HLCS. This numerical simulator is based on the open-source physics engine Bullet Physics Engine (BPE), which applies Newton's laws of motion to rigid bodies. From an initial theorical placement grid for Cubipod HLCS, a series of numerical realistic unit placement tests are carried out to emulate the placement process at prototype scale; placement velocity and spatial deviation of crawler cranes are given parameters associated with each specific project. Considering the placement velocity and spatial deviation during construction, the quality of each specific placement grid is associated with the measured placement errors and the corresponding initial construction deviation to HLCS. This numerical methodology is valuable to understand the influence and the uncertaintly of the construction procedure of armor layers in mound breakwaters.

Influence of marine habitat on microplastic prevalence in forage fish and salmon in the Salish Sea

Microplastics are increasingly prevalent in marine systems and are a growing concern as a marine pollutant and contaminant with consequences for high trophic level consumers, including humans. Given evidence that links plastics to degraded ecosystem functioning and organismal health, there is increased interest in understanding the prevalence, fate and consequences of marine plastics. Microplastics contain and absorb harmful chemicals which may serve as endocrine disruptors and have negative implications for growth, reproductive health, and longevity. To expand current knowledge on microplastics in coastal marine ecosystems and the potential for biomagnification in marine food webs, we conducted stomach analyses of microplastics in Pacific salmon (Oncorhynchus spp.) and Pacific sand lance (Ammodytes personatus), an important prey for salmon. Prevalence of microplastics was substantial; 77 % of all salmon and 25 % of all sand lance stomachs contained at least one microplastic. Fish were sampled at multiple sites throughout the inland Salish Sea, including beaches and sediment bedforms for Pacific sand lance and open-water pelagic habitat for Pacific salmon. Pacific sand lance sampled at beach sites had more microplastics compared to those sampled in subtidal sediments and there were more plastics in sand lance at a protected beach site as compared to an exposed beach site. Prevalence of plastics in salmon differed according to species and included analyses of pink salmon (Oncorhynchus gorbuscha), Chinook (Oncorhynchus tshawytscha), and Coho salmon (Oncorhynchus kisutch); plastics were predominantly fibers in all species, though there were relatively higher rates of ingestion of films and particles in Chinook. Comparisons between plastic concentrations and stomach fullness indicated a slight negative trend, suggesting that plastics may be retained. Further investigation is needed to develop a more thorough understanding of the prevalence and fate of microplastics in coastal marine systems such as the Salish Sea, their concentration within marine food webs, and the implications for species targeted in fisheries.

Numerical Modelling of Beach Profile Evolution with and without an Artificial Reef

With the recent development from grey infrastructures to green infrastructures, artificial reefs become more popular in coastal protection projects. To investigate the responses of beach profile evolution to the presence of an artificial reef, a non-hydrostatic model is established. Both hydrodynamic and morphodynamic evolution for the beach with and without an artificial reef are compared under regular wave conditions. In addition, the protected beach profile evolution by an artificial reef is discussed under irregular wave conditions. Three key parameters in non-hydrostatic simulation are considered for sensitivity analysis, including maximum wave steepness criterium (maxbrsteep), water depth factor (depthscale), and equilibrium sediment concentration factor (sedcal). The numerical results under regular wave conditions indicate that the artificial reef enhances wave attenuation by inducing wave breaking. In addition, the artificial reef reduces local flow velocity and offshore sediment transport by 51%, therefore decrease the total erosion by 53%. Over the artificial reef, wave skewness and asymmetry go through a drastic change. Under irregular wave conditions, short waves contribute to the wave energy mainly and reflection-induced standing wave effects decline considerably. It demonstrates that the artificial reef can protect the beach from regular and irregular waves by reducing erosion and offshore transport of suspended sediments. Moreover, in the wave breaking area, the increase of maximum wave steepness criterium may give arise to the wave height. The morphological evolution is more sensitive to water depth factor than equilibrium sediment concentration factor, because the former is a controlling factor for beach profile characteristics while the latter forms the sandbar varying irregularly in shape.

Analytical studies of the dynamics of pocket beach

The beach site is located in the utmost northeastern part of the Nevskaya Bay. A boulder dam is built on the western side, which, however, fails to protect the beach from the effects of waves that cause longshore sediment transport. The planned construction of transverse beach–retaining structures outlines in the “Water Sports Base in Primorsky District” initiative, mightchange the current situation. This study objective is to predict the evolution of the coastal contour resulting from the planned construction in the next few decades. A natural analogue of such an artificial structure could be a pocket beach located between two natural promontories. The sediment equilibrium at this study location includes three main components: volumes of erosion, accumulation and bypassing. The results include the computed wave patterns and the movement of sediment along the shoreline. The lateral sediment transport diminishes notably over time, driven by the alteration of the shoreline contour and the reduction in the angle between the wave equilibrium and the coastal resultant. The erosion and accumulation volumes increase over time, but their rates slow down. The shoreline displacement becomes more prominent over time; however, the rates of erosion differ from accumulation. The shoreline is moving particularly fast in the first years after construction, and then the process slows down gradually. The introduction of artificial beach protection structures in the 300th Anniversary Park of St. Petersburg will considerably reduce both the pace of beach erosion and the affected area. However, the erosion process will not be completely halted.

A first approach of beach sanding on the Black Sea Romanian’s coast

The Romanian coastline, which is subject to complex processes of geomorphological evolution due to beach sanding actions, as well as other natural and anthropogenic factors. Beach sanding is an important action in the maintenance and development of coastal areas, it provides protection against erosion, contributes to the formation and maintenance of beaches, as well as to the preservation of coastal ecosystems The main source of sand for Romanian beaches is coastal transport, i.e. the movement of sand along the coast under the action of values, current and wind. Naturally, there is some redistribution of sand along the coast, with an area where it accumulates and an area where it is lost. However, human intervention and other influences can disrupt this natural balance. In order to counteract the negative impact of insufficient sanding, various coastal management measures have been implemented in Romania. These include the artificial replenishment of beaches by bringing in additional sand from the seabed or other sources, as well as the construction of beach protection and stabilization works.

The Need for an Environmental Notification System in the Lithuanian Coastal Area

The Lithuanian coastal area is divided by the jetties of the Port of Klaipėda and represents two geomorphologically distinct parts. Local companies and institutions contribute to shaping the coastal area through infrastructure development. Awareness of the changes in the coastal zone can play an important role in the planning and economic feasibility of activities in the Klaipėda coastal region. Therefore, developing a notification system that provides long– and short–term monitoring data for the Lithuanian coastal zone is necessary. In order to do so, the authors intend to create a system that should provide a link between long– and short–term observation and monitoring data for stakeholders, such as wind speed and direction, wave direction and significant height, water and air temperature, atmospheric pressure, sediment size, and distribution, height above sea level, shoreline position, beach width, change in beach protection measures, beach wreckage, and marine debris management, in order to provide timely notifications to end users.

Modelling and evaluation of beach morphodynamic behavior: A case study of Dongsha Beach in eastern China

Beaches provide natural protection for coast and ecosystems. Storm surges and waves make significant impacts on the topographic changes of beaches, subsequently causing crises of coastal erosion and management. Beach protection and nourishment projects is growing considerably along the world. Five profiles of Dongsha Beach located in the southeast of Zhujiajian Island, eastern China, were measured and used to analyze the cross-shore profile changes, longshore sediment transport, beach rotation and equilibrium shoreline and profile. Delft3D Flow/Wave and XBeach models were established and calibrated to investigate the morphological responses of Dongsha Beach. It was found that: (1) the longshore sediment transport dominated the changes of erosion and accretion sediment volume compared to the cross-shore sediment transport; (2) the shoreline of Dongsha Beach was not in equilibrium condition compared to the profile equilibrium conditions; (3) the longshore sediment transportation was the main reason of the erosion because the shoreline changes caused by longshore sediment transport during the storm condition could not be restored during calm sea periods; (4) the correlation between wave induced currents and Hs2·T was good and the dominating wave direction was 90°. Finally, sediment nourishment projects named N1∼N3 were assumed and simulated to identify the optimum for the dynamic balance of Dongsha beach. Sediment sources with D50 of 0.5 mm should be chosen in sediment nourishment projects, and the nourished area should be selected in N1 or N3 of the beach. The numerical model established in this study could be a useful tool to predict the future erosion and accretion of beaches. This study can provide a useful understanding and reference especially for the embayed beach nourishment, making the beach management decisions more scientific and reasonable.

Design and implementation of an innovative wind power system for beach erosion protection and nourishment

Beach erosion phenomena have become increasingly frequent and devastating with serious economic damage on tourism. A relatively recent technique of beach protection and nourishment is based on the creation along the shoreline of an unsaturated sandy zone, in which the level of the phreatic surface is lowered by means of buried drains connected to electric suction pumps. The main problem encountered in this solution is the need to guarantee the drainage when the erosive activity is maximum in the presence of intense thunderstorms that often produce malfunction and outage problems of the power supply. This paper shows the realization of a “green” solution based on a totally mechanical design and construction approach, achieved by connecting a 3.5-meter single-bladed wind turbine to a submerged axial pump with optimized volute by means of a vertical shaft placed inside the tower. The system is managed by a mechanical pitch controller studied for starting and limiting power in exceptional winds.

Status of the Western Snowy Plover in Coastal Los Angeles and Orange Counties, California

From 2004 to 2021 we monitored the Western Snowy Plover (Charadrius nivosus nivosus) in coastal Los Angeles and Orange counties, California. Following an absence of 68 years, it returned to nest in 2017. Since then, the plovers have nested at three locations in Los Angeles County and four in Orange County, where numbers of nests at Anaheim Bay, Bolsa Chica State Beach, and Huntington State Beach increased. Protective beach management and nest enclosures presumably contributed to the increase of nests and hatching success at these sites. However, the number of nonbreeding Snowy Plovers in coastal Los Angeles County has declined, most steeply at Zuma Beach. At nonbreeding roosts in Orange County numbers at Balboa Beach and San Onofre State Beach declined, but countywide numbers were stable. All sites at which plovers roost experience human-related disturbance, which may include vehicles driving through them regularly, beach grooming that removes wrack and foraging resources, dogs chasing and flushing roosting plovers, and nearby large recreational events and summer camps as nonbreeding plovers return in July. Most sites lack consistent protective measures. Plover mortality has resulted from vehicle strikes and dogs. We recommend management that includes the establishment of special protection zones, restrictions on sand grooming, wrack removal, and vehicle traffic, and installation of protective enclosures around roost sites.