Dry Beach Research Articles

Effects of Anthropic Structures on Morphodynamic Beach Evolution along the Gulf of Roses (Northwestern Mediterranean, Spain)

This study conducts a morphodynamic analysis of beaches located in the northern sector of the Gulf of Roses (NW Mediterranean, Spain). The primary objective is to investigate mid-short (2004–2020) term spatial and temporal variations in shoreline position and sedimentological behaviour. The study area covers the northern part of the gulf, spanning 9.86 km, and includes both natural beaches and heavily anthropized ones. The following GIS methodologies were employed to study the variations in the coastline: QGIS for areas and DSAS-ArcGIS for transects, quantifying coastal changes from 2004 to 2020. Sediment samples were collected from both the dry beach and swash areas for each profile. The results reveal minor discrepancies in shoreline evolution data, depending on the method used (transects or areas). Profile-based analysis shows an average annual rate of −0.11 m·y−1 (ranging between 0.53 and −0.55 m·y−1), while areal-based results (2004–2020) indicate a total loss of −20,810 m2 (−1300 m2·y−1). Sediment grain size decreases northward (from 745 to 264 µm in the swash zone). Changes in shoreline position and grain size illustrate the impact of various anthropogenic structures on morphodynamic behaviour. These structures preferentially deposit specific grain sizes and impede sediment transport, which will cause an advance in the position of the shoreline and sediment grain sizes upstream and a reverse process downstream. This study underscores the influence of coastal anthropization on beach morphology and sedimentology, generating distinct morphodynamic behaviour.

Deep Learning-Based Calculation Method for the Dry Beach Length in Tailing Ponds Using Satellite Images

The dry beach length determines the hydraulic boundary of tailings impoundments and significantly impacts the infiltration line, which is crucial for the tailings dam. A deep learning method utilizing satellite images is presented to recognize the dry beach area and accurately measure the length of dry beaches in tailing ponds. Firstly, satellite images of various tailing ponds were gathered and the collection was enlarged to create a dataset of satellite images of tailing ponds. Then, a deep learning method was created using YOLOv5-seg to identify the dry beach area of tailing ponds from satellite images. The mask of the dry beach region was segmented and contour extraction was then carried out. Finally, the beach crest line was fitted based on the extracted contour. The pixel distance between the beach crest line and the dry beach boundary was measured and then translated into real distance by ground resolution. This paper’s case study compared the calculated length of dry beach with the real length obtained by field monitoring. The results of the case study showed that the minimum error of the method was 2.10%, the maximum error was 3.46%, and the average error was 2.70%, indicating high precision for calculating dry beach length in tailing ponds.

Assessment of atmospheric air pollution in Dnipro city as a result of dust entrainment from the ash-disposal areasof Prydniprovsk TPP

Purpose. The purpose of this work is to assess the pollution of atmospheric air in Dnipro city as a result of dust entrainment from the ash-disposal areas of Prydniprovsk TPP. The methods. Assessment of atmospheric air pollution in the city of Dnipro as a result of dust entrainment from the ash-disposal areas of Prydniprovska TPP was carried out as follows: physical and chemical characteristics of the stored fly ash were determined; specific dust entrainment from the surface of dry beaches of ash-disposal areas under the most favorable conditions was determined; mathematical modeling of the spread of atmospheric air pollution of Dnipro city by suspended particles was carried out using UPCAP "ECO Center"program; a comparative assessment of dust entrainment reduction due to the gradual processing of the deposited fly ash was carried out. Findings. Almost 100% of the total mass of ash consists of particles smaller than 80 μm, the content of particles smaller than 10 and 2.5 μm is 27.7 and 8.2%, respectively. The main chemical compounds contained in ash are silicon dioxide, aluminum oxide, iron (III) oxide and carbon. The gross entrainment of substances in the form of suspended fine-grained solid particles from the surface of the dry beaches of the Prydniprovska TPP ash-disposal facilities is 18,654 tons per year. The area of atmospheric air pollution of Dnipro city by suspended particles is about 850 km2 and covers Samarskyi, Sobornyi, partly Industrialnyi and Shevchenkivskyi Districts. As a result of the implementation of a waste-free technology for the processing of fly ash with the utilization of the iron-containing fraction, the area of pollution can be reduced by 13.5 times up to 63 km2, the contamination zone in this case will cover underpopulated part of Samarskyi District of the city of Dnipro. Scientific novelty. A refined dependence of the particle size distribution of the mature Prydniprovsk TPP fly ash particles was determined for the further assessment of potential dust entrainment. For the first time, modeling of the distribution of fine-grained particles of fly ash of the Prydniprovsk TPP in the atmospheric air of the city of Dnipro was carried out, taking into account meteorological conditions, conditions of dust formation and particle size distribution. Practical implementation. The results of the research can contribute to reducing the level of atmospheric air pollution in the city of Dnipro. This will improve the quality of life of the local population and protect the natural environment from negative impacts. Research results can also be a basis for the development and implementation of technological solutions for the waste-free processing of stored fly ash with marketable products obtaining.

Experimental Study on Tailings Deposition Distribution Pattern and Sedimentation Characteristics.

Tailings pond accidents frequently occur during an extended period, resulting in loss of life and property, wastage of resources, and environmental pollution. Relying on tailings pond engineering, this paper carried out sample particle fragmentation experiments and settling column experiments to explore the deposition distribution pattern of tailings in both horizontal and vertical directions as well as the impact of particle size distribution on the sedimentation stratification effect. The results show that the median particle size on the dry beach surface in the horizontal direction slowly decreased with the increase in the distance from the subdam. The particle size of tailings showed great fluctuations in the vertical direction, which gradually became finer with the increase in the depth overall. At the same time, saturated sedimentation experiments suggested the inconsistent variation rule with the field test, namely, coarse on the bottom and fine at the top, and the change in particle size greatly affected the tailing sedimentation stratification effect. With the increase in fine particle content in tailings, the appearance time of the water-sand interface was shortened to within 30 min, but the sedimentation and consolidation completion times were delayed to about 1400 min. The settling column results indicate that the increase in fine particle content gradually weakened the sedimentation stratification effect, and the sedimentation pattern transformed from independent sedimentation to floc-type average sedimentation, which led to the enhanced water-retaining property of the settled layer. This may lead to an increase in the saturation line and a decrease in the length of the dry beach, seriously affecting the safe operation of the tailings pond. The research results provide some theoretical guidance and basic data for analyzing the consolidation efficiency of tailings and the stability of the tailings pond.

Fetch‐driven aeolian sediment transport on a sandy beach: A new study

AbstractThis study examines the effect of fetch distance on aeolian sediment transport and the corresponding growth rate of aeolian transport rate on a sandy beach under varying wind speeds. Eight experiments were conducted on both dry and intertidal beach areas, with wind speeds ranging from 9 to 17 m/s. Vertically stacked sand traps were used to measure transport rates over distances up to 100 m, with experiments lasting 20–40 minutes. Results indicate an initial increase in transport rate until the critical fetch distance, followed by a subsequent decrease in sediment transport with further fetch distance. Critical fetch distances, corresponding to maximum transport rates, ranged from 23.8 to 103.5 m. A strong linear correlation was observed between wind speed and critical fetch distance, suggesting that higher wind speeds necessitate longer fetch distances for maximum transport. Furthermore, established formulations by van Rijn and Strypsteen are tested to estimate maximum sediment transport and critical fetch distance based on grain‐related shear velocity. Combining all experiments showed that the growth rate in transport up to the point of critical fetch can be best described by a trigonometric function. These findings contribute to a better understanding of the fetch effect on aeolian sediment dynamics in coastal sandy environments.

Seepage stability analysis of geogrid reinforced tailings dam

To investigate the influence of a geogrid-reinforced tailings dam on the seepage stability of the dam body, this paper was based on the field test of a reinforced tailings accumulation dam. The study utilized the finite element strength reduction method to simulate the stability of the main dam of the Fengshuigou tailings reservoir under different seepage conditions using ABAQUS software. Additionally, the paper discussed the impact of conventional heightening, dry beach length, and geogrid reinforcement on the position and safety factor of the saturation line of the dam body. The results showed that when the dam body was raised, the saturation line rose by 2.8–5.3 m, resulting in a decrease in the safety factor. The geogrid effectively reduced the height of the saturation line in the tailings dam. In comparison to the unreinforced condition (dam heightening), the saturation line of the tailings dam decreased by 0.9–2.8 m under the local reinforcement condition and by 3.2–12.5 m under the overall reinforcement condition. The geogrid significantly improved the stability of the tailings dam. Furthermore, under the local reinforcement condition, the safety factor of the dam increased by 3.8–5.5%, and under the overall reinforcement condition, it increased by 35.9–42.9%, when compared to the unreinforced condition. Increasing the dry beach length improved the stability of the tailings dam, and under normal working conditions, the safety of the tailings dam was much higher than under the minimum dry beach condition. These results served as a reference for the design of the dam and the new tailings reservoir, laying a foundation for the sustainable development and environmental protection of the tailings pond.

Research on the Assessment Technology of Land Available for PV

Based on the high-resolution satellite image data, the information mining technology of the available surface elements of PV is studied, and the investigation of the available surface elements of PV in 98 counties and cities of South Hebei grid is realized. Based on the large-scale and high-resolution remote sensing data obtained by multi-source remote sensing data fusion technology, the depth-learning-based surface feature recognition technology for photovoltaic development is studied. Based on the method of automatic identification and artificial combination of depth-learning, it can identify the available ground elements (roof, water surface, road surface, dry beach, etc.), the available surface elements of PV in 98 counties and cities of Hebei South Grid were obtained. From the overall point of view, the photovoltaic land, the building occupies the main position, in the four cities are relatively high, are in the 6% ~ 15%

Laboratory evaluation of the effectiveness of nature-assisted beach enhancement techniques

Beaches are eroded and accrete under the effect of storms and calm marine conditions, respectively. Normally, beaches reach their narrower state in spring, after the action of winter storms. Accretion processes are slow, and maximum beach recovery doesn't occur until late summer. Sometimes this recovery is not enough to reach the width the beach had the previous year, producing a progressive shoreline retreat and an increased risk of dune erosion and inland flooding during the following winter seasons. The need for wider beaches in early summer for touristic purposes and social support to soft-engineering measures, have increased the interest in Nature-Assisted Beach Enhancement (NABE) techniques. In this study, reduced-scale laboratory experiments on beach ploughing and scraping allowed the comparison of various of these techniques and their effectiveness in controlled conditions for the first time. The beach widening and accretion achieved for five different NABE geometries were analysed and contrasted with natural (control) conditions. Our results show that the best technique is goal-dependent. For dry beach widening, ploughing is recommended as an effective and easy-to-design technique. Scraping the lower intertidal area and placing the sand on an intertidal bar or the beachfront are also effective alternatives if adequately designed. For dune nourishment, the best option is scraping the upper intertidal area and using the borrowed sand for dune regeneration. In general, all the analysed techniques enhance natural beach accretion, in collaboration with natural processes, thus reducing the human action required to achieve the desired objectives from a Building with Nature perspective.

The Stability of Dams with Different Stoping Elevations in the Tongling Valley-Type Tailings Impoundment: A Case Study in Yunnan China

Significant interest has been focused on recovery rates, recovery options, and recovery utilization when tailings impoundments are re-mined. However, the stability of the tailings dams during the recovery process is also a severe issue. Based on engineering geological surveys and laboratory tests, the evolution of the Tongling tailings impoundment’s instability characteristics under different recovery heights and diverse working conditions was analyzed by numerical simulation. Firstly, with the help of 2D software, the position of the tailings dam infiltration line and the alteration of the dam safety factor during the stoping process were calculated. Secondly, 3Dmine (2017) software was used to create the 3D surface structure of the tailings impoundment, and then a 3D numerical analysis model was established by means of Midas GTS NX software. The numerical simulation of seepage and stress analyses were conducted based on the model. Consequently, the evolution of the stability characteristics of tailings dam under different operating conditions was calculated. The research demonstrates that the dry beach length of the tailings pond gradually reduces with a decrease in the extraction height, resulting in a lower infiltration line. Under flood conditions, the saturation line has partial overflow due to the poor seepage discharge capacity of the dam. The total displacement of the dam body is inversely proportional to the retrieval height. The more extreme the analyzed working conditions, the more the safety factor will be reduced. Additionally, the plastic variation area of the dam body will be more comprehensive, which will increase the risk of a dam collapse.

Quantification of longshore sediment transport and compartments in urban areas: A case study of shores of Tallinn, the Baltic Sea

We analyse sediment transport patterns along shores of urbanised bays of complicated shape. The focus is on shores of Tallinn on the southern coast of the Gulf of Finland, the Baltic Sea. A detailed reconstruction of the wave climate in the study area with a spatial resolution of 260 and 470 m is generated using triple-nested high-resolution versions of the WAM and SWAN models. The models are forced with three wind data sets: 32 years of high-quality one-point marine winds, ERA5 winds for 1990–2021, and BaltAn65+ winds for 1986–2005. The main properties of potential wave-driven alongshore transport and its convergence and divergence points along sedimentary shores of five bays of greatly different size and orientation are established from the time series of wave properties using the CERC approach. Four smaller bays serve as separate sediment compartments. Harbours and jetties divide the sedimentary shore of the interior of the largest bay, Tallinn Bay, into one almost isolated and four weakly connected compartments. The southern shore of this bay hosts a persistent divergence area of littoral drift that subdivides the almost isolated compartment into two distinct sedimentary cells. Changes to the dry beach in a major accumulation area in one of these cells are evaluated using a combination of airborne and terrestrial laser scanning.

LIFE-CYCLE ANALYSES OF SUBAERIAL BEACH NOURISHMENTS WITH CONCURRENT NEARSHORE PLACEMENT OF DREDGED SEDIMENT

The practice of placing sediment dredged from navigation channels in the downdrift nearshore is common in the US. These nearshore placements of dredged sediment, or nearshore nourishments, often correspond to a variety of positive nearshore morphology and shoreline stability benefits. They are often able to beneficially use sediment not directly suitable for dry beach placement, which increases the volume available to nourish the full beach profile and keeps sediment in the system that would otherwise be removed. Concentrating dredged sediment placement in nearshore berms may dissipate wave energy farther offshore and reduce the sediment needs of the co-located shoreline. This strategy may be able to extend subaerial beach nourishment lifespan, which typically cost substantially more. Co-located nearshore and subaerial beach nourishments could lead to large cost savings, but the potential to increase subaerial beach fill lifespan has not previously been quantified.

SPATIAL VARIABILITY IN BEACH-FACE SLOPES FROM SATELLITE REMOTE SENSING

The beach face is the most seaward region of the dry beach. This region is the primary interface between land and ocean, and therefore has a great influence on coastal processes such as the exchange of sediment between land and sea or the reflection of wave energy at the shoreline. In particular, the slope of the beach-face, is an important parameter in coastal engineering to calculate the vertical and horizontal excursion of wave run-up (Stockdon et al., 2006). Yet, despite the importance of the beach-face slope parameter in many formulations used by coastal engineers, this quantity remains poorly mapped along the world’s sandy coastlines and the absence of large-scale datasets of beach-face slope is presently limiting our ability to deploy coastal inundation forecasting systems (O’Grady et al., 2019). This work describes a novel methodology to estimate beach-face slopes with satellite remote sensing and presents large-scale datasets of beach-face slopes along open-coast sandy coastlines around the Pacific Rim.

AN INTEGRATED MACHINE LEARNING-PROBABILISTIC APPROACH TO PREDICT BEACH VOLUME CHANGE

In the DataBeach study a machine learning model was developed with the aim to improve the efficiency and sustainability of design of soft coastal defense projects. A morphological model based on machine learning was trained and tested to predict beach volume changes with significantly reduced computational time compared to traditional process-based models. The machine learning model was then applied, combined with a ‘penalty function’ for inclusion of morphological feedback, to predict beach volume changes for the study area of approximately 2 km alongshore and on a 10-year project timescale. In order to run many different scenarios for the 10-year prediction, a probabilistic methodology was developed to take into account the uncertainties in this time period. The machine learning-based model provides great benefits for probabilistic simulations, due to the lower computational time, compared to process-based numerical models such as XBeach, and a flexible way in which it can incorporate measurement data. The performance of the tested machine learning models was comparable to that of the short term volume predictions of XBeach. Comparison of 10-year predicted volume changes using the machine learning model and measured beach topography (LiDAR) showed good agreement between measured and predicted volume changes for the dry beach area (when accounting for nourishments), but overestimation in the beach volume change predictions for the intertidal beach. These differences are partially attributed to the poor performance on XBeach for long term, normal wave conditions, which are an important factor in the intertidal area.

Foredune defending role: Vulnerability and potential risk through combined satellite and hydrodynamics approach

The paper presents an approach to assessing potential risks for coastal areas, where the foredune acts as the first and main line of defense against storm surges. The local correction technique for satellite data via morphodynamics and hydrodynamics features, applicable for the southern part of the Baltic Sea was developed. The proposed combination of regionally adapted height of the wave run-up and the surge height made it possible to clarify the width of the beach through analyzing ESA Sentinel-2a satellite images. Using digitized shorelines from ESA Sentinel-2a imagery as a reference, together with the results of modeling the near-hydrodynamic conditions, a study of the beach width dynamics between measurements was performed. This is due to the regularity of satellite data being affected by cloud cover and the period of circulation. Identifying hot spots on the shore made it possible to establish areas with a significant excess in the repeatability of small dry beach width and, correspondingly, the erosion rate. The hot spots were detected within the Curonian Spit protective dune ridge, identifying the vulnerable areas, which are able to serve as breach points to flooding. The hydrological analysis of the flood zones under storms of varying frequency was performed, and predictions were made regarding the regional sea level rise by BACC and Team (2015) regional climate analysis. The work shows the possibilities of combining hydrodynamic and hydrological modeling, satellite observations into a single forecasting and assessment system, which allows to analyze and model risks of various origins. The results obtained can significantly improve the existing models or become the background for the integrated coastal zone management system, especially in protected natural areas.

WayFAST: Navigation With Predictive Traversability in the Field

We present a self-supervised approach for learning to predict traversable paths for wheeled mobile robots that require good traction to navigate. Our algorithm, termed WayFAST (Waypoint Free Autonomous Systems for Traversability), uses RGB and depth data, along with navigation experience, to autonomously generate traversable paths in outdoor unstructured environments. Our key inspiration is that traction can be estimated for rolling robots using kinodynamic models. Using traction estimates provided by an online receding horizon estimator, we are able to train a traversability prediction neural network in a self-supervised manner, without requiring heuristics utilized by previous methods. We demonstrate the effectiveness of WayFAST through extensive field testing in varying environments, ranging from sandy dry beaches to forest canopies and snow covered grass fields. Our results clearly demonstrate that WayFAST can learn to avoid geometric obstacles as well as untraversable terrain, such as snow, which would be difficult to avoid with sensors that provide only geometric data, such as LiDAR. Furthermore, we show that our training pipeline based on online traction estimates is more data-efficient than other heuristic-based methods.

Interconnections between Coastal Sediments, Hydrodynamics, and Ecosystem Profiles on the Mexican Caribbean Coast

The interconnections between hydrodynamics, coastal sediments, and ecosystem distribution were analysed for a ~250 km strip on the northern Mexican Caribbean coast. Ecosystems were related to the prevailing and extreme hydrodynamic conditions of two contrasting coastal environments in the study area: Cancun and Puerto Morelos. The results show that the northern Mexican Caribbean coast has fine and medium sands, with grain sizes decreasing generally, from north of Cancun towards the south of the region. Artificial beach nourishments in Cancun have affected the grain size distribution there. On beaches with no reef protection, larger grain sizes (D50 > 0.46 mm) are noted. These beaches are subject to a wide range of wave-induced currents (0.01–0.20 m/s) and have steeper coastal profiles, where sediments, macroalgae and dune-mangrove systems predominate. The coastline with the greatest amount of built infrastructure coincides with beaches unprotected by seagrass beds and coral reefs. Where islands or coral reefs offer protection through less intense hydrodynamic conditions, the beaches have flatter profiles, the dry beach is narrow, current velocities are low (~0.01–0.05 m/s) and sediments are finer (D50 < 0.36 mm). The results offer a science-based description of the interactions between physical processes and the role played by land uses for other tropical coastal ecosystems.

Beach-face slope dataset for Australia

Abstract. Sandy beaches are unique environments composed of unconsolidated sediments that are constantly reshaped by the action of waves, tides, currents, and winds. The most seaward region of the dry beach, referred to as the beach face, is the primary interface between land and ocean and is of fundamental importance to coastal processes, including the dissipation and reflection of wave energy at the coast and the exchange of sediment between the land and sea. The slope of the beach face is a critical parameter in coastal geomorphology and coastal engineering, as it is needed to calculate the total elevation and excursion of wave run-up at the shoreline. However, datasets of the beach-face slopes along most of the world's coastlines remain unavailable. This study presents a new dataset of beach-face slopes for the Australian coastline derived from a novel remote sensing technique. The dataset covers 13 200 km of sandy coast and provides an estimate of the beach-face slope every 100 m alongshore accompanied by an easy-to-apply measure of the confidence of each slope estimate. The dataset offers a unique view of large-scale spatial variability in the beach-face slope and addresses the growing need for this information to predict coastal hazards around Australia. The beach-face slope dataset and relevant metadata are available at https://doi.org/10.5281/zenodo.5606216 (Vos et al., 2021).

Are tropical estuaries a source of or a sink for marine litter? Evidence from Sabaki Estuary, Kenya

Litter surveys were carried out in August and September 2020 to determine the contribution of Sabaki River and estuary in modifying the quantities of litter entering the oceans. The river discharged 0.035 items m−3s −1 translating to an estimated annual litter flux of between 6,622,560 and 614,952,000. The surveys in the estuary revealed that plastics contributed 90.8% of the total litter. Wet and dry zones had mean litter accumulation rates of 2.7 ± 1.1 and 4.4 ± 3.5 items m−1 day−1 respectively. 69.8% and 77.4% of branded litter were of Kenyan origin and food packaging material respectively. The litter turnover was slightly higher in the dry beach zone compared to the wet zone with a Whitakker Beta diversity of 0.36 and 0.33 respectively. Sabaki estuary acted as a sink for litter during flooding (through burial) and as a source (through exposure of buried litter due to wind and rain action).

A fully predictive model for aeolian sand transport, part 3: Verification and application of model for natural beaches

This paper presents extensive research results on the verification of a new transport equation for dry and moist sand at field sites and is a continuation of earlier work (Van Rijn and Strypsteen, 2020). A new trap-type instrument (LVRS-sampler) for measuring the sand transport rate of sliding, rolling and saltating particles was designed and used at many natural beach sites in Belgium and The Netherlands. A short mast equipped with three mini wind cup meters was used to measure the velocity distribution in the lowest 1 m of the boundary layer flow. Many new data sets (81 data) of aeolian sand transport for dry and moist beach surface conditions were obtained using the new equipment and used for verification of the new prediction method. Older field data (48 data points) from the literature were also used for verification. The score of the predicted sand transport based on the new VR-method is 87% within a factor of 2 of measured values for dry sand and 91% for moist sand. The modified Bagnold-transport equation was also used for verification of the available field data with scores of 79% and 67%. As a practical example, the new VR-sand transport equation was applied to calculate the annual aeolian sand transport on a Dutch beach site using wind velocity and rainfall data from a local weather station including rain fall effects (moist sand) and conversion of inland wind velocities to beach velocities (upscaling of results).

Beach-face slope dataset for Australia

Abstract. Sandy beaches are unique environments composed of unconsolidated sediments that are constantly reshaped by the action of waves, tides, currents, and winds. The most seaward region of the dry beach, referred to as the beach face, is the primary interface between land and ocean and is of fundamental importance to coastal processes, including the dissipation and reflection of wave energy at the coast, and the exchange of sediment between the land and sea. The slope of the beach-face is a critical parameter in coastal geomorphology and coastal engineering, necessary to calculate the total elevation and excursion of wave run-up at the shoreline. However, datasets of the beach-face slope remain unavailable along most of the world’s coastlines. This study presents a new dataset of beach-face slopes for the Australian coastline derived from a novel remote sensing technique. The dataset covers 13,200 km of sandy coast and provides an estimate of the beach-face slope at every 100 m alongshore, accompanied by an easy to apply measure of the confidence of each slope estimate. The dataset offers a unique view of large-scale spatial variability in beach-face slope and addresses the growing need for this information to predict coastal hazards around Australia. The beach-face slope dataset and relevant metadata are available at https://doi.org/10.5281/zenodo.5606217 (Vos et al., 2021)