Types Of Erosion Research Articles

Obliquely incident seismic response of subway stations following urban soil internal erosion

Urban groundwater infiltration resulting from tropical storm rainfall can lead to internal soil erosion and ground subsidence. The long-term effects of these phenomena may result in uneven settlement of the subway system, posing risks to its safety and operational integrity. Suffusion poses a significant hazard to long-term subway operation. It is a type of soil internal erosion characterized by the migration of fine particles from the pore channels between coarse particles. This study focused on the performance degradation of different gap-graded sands caused by internal erosion, observed through triaxial compression tests. Using the cap plasticity model and considering mechanical parameters before and after soil erosion, a refined two-dimensional finite element model of a soil subway station structure based on ABAQUS was developed to analyze the deformation and damage pattern of the subway structure resulting from soil internal erosion and earthquake. The results of this study demonstrated that localized internal soil erosion significantly contributes to uneven settlement in subway stations, potentially compromising their seismic performance during oblique seismic excitations.

Factors Influencing Ephemeral Gullies at the Regional Scale: Formation and Density

Ephemeral gully (EG) erosion is an important type of water erosion. Understanding the spatial distribution of EGs and other influencing factors at a regional scale is crucial for developing effective soil and water management strategies. Unfortunately, this area has not been sufficiently studied. The present study visually interpreted the EGs based on Google Earth images in 137 small watersheds uniformly distributed in the Loess Plateau, compared them with measured results, and analyzed the factors influencing EG formation and density using GeoDetector. The results showed that visually interpreting EGs from Google Earth images was suitable for EG regional studies. Out of the 137 small watersheds, 33.6% had EG occurrence with an average density of 3.41 km/km2. Rainfall (R) and slope gradient (S) were the primary factors influencing the formation of EGs, while the area proportion of sloping farmland (APSF) and soil erodibility (K) were the main factors affecting EG density. The interaction of dual factors had a greater influence compared to single factors, with the interaction between S and Normalized Difference Vegetation Index (NDVI) having the greatest impact on EG formation and the interaction between K and NDVI on EG density. Although natural forces significantly influence whether EGs can form in a specific area, human activities greatly affect the density of the gullies that develop. This underscores the importance of proper land management in controlling gully erosion. These findings could provide theoretical support for EG prediction models and a scientific basis for soil and water loss control strategies at the regional scale.

Effect of degradation in polymer scaffolds on mechanical properties: Surface vs. bulk erosion

Porous polymeric scaffolds are used in tissue engineering to maintain or replace damaged biological tissues. Once embedded in body, they are involved into different physical and biological processes, among which their degradation and dissolution of their material can be singled out as one of the most important ones. Degradation parameters depend mostly on the properties of both the material and surrounding native tissues, which can substantially alter the original mechanical parameters of the scaffolds. The aim of this study is to examine the change in the effective mechanical properties of functionally graded additively manufactured polylactide scaffolds with a linear porosity gradient and morphology based on triply periodic minimal surfaces during simultaneous degradation and compressive loading. Two main types of scaffold-degradation processes, bulk and surface erosions are simulated with two suggested modelling methods. The fundamental differences in the proposed approaches are identified and the influence of different types of scaffold morphology on the change in effective elastic properties is evaluated. The results of this study can be useful for design of optimal scaffolds taking into account the effect of the degradation process on their structural integrity.

Evaluating the influence of Cynodon dactylon on the wave force and wave erosion in the water-level fluctuation zone of the Three Gorges Reservoir Area

Wave erosion is the main erosion type in the water-level fluctuation zone (WLFZ) of the Three Gorges Reservoir Area (TGRA). Despite vegetation can effectively mitigate wave erosion in the WLFZ, its influence on the wave force and wave erosion remains unclear. Therefore, the wave experiments were conducted under 3 Cynodon dactylon coverage rates (0, 30% and 60%) and 9 wave conditions (3 wave heights of 4, 6 and 8 cm combined with 3 wave periods of 1, 2 and 3 s) to analyse the wave force (expressed as the wave pressure on the slope surface and the pore water pressure in the slope) and wave erosion rate, and the factors influencing wave erosion were identified. The results indicated that the wave pressure, pore water pressure and wave erosion rate increased by 19.14%–104.75%, 16.84%–65.04% and 23.33%–91.64%, respectively, as wave height increases. The wave pressure decreased by 1.50%–31.23% followed by an increase by 22.05% to 87.10% with the increase of wave period, whereas the pore water pressure and wave erosion rate decreased by 28.33%–53.59% and 20.46%–63.59%, respectively. However, these quantities decreased by 2.10%–50.84%, 17.06%–40.23% and 17.28%–82.18%, respectively, with the increase of Cynodon dactylon coverage rate. It was also discovered that the pore water pressure and Cynodon dactylon coverage rate attained the highest positive and negative correlation coefficients with the wave erosion rate, respectively. In addition, pore water pressure accumulation is the most critical influence factor on wave erosion, and Cynodon dactylon could effectively reduce the pore water pressure via its roots, thus improving the slope wave erosion resistance. This study could be useful to understand the mechanism of plants on controlling wave erosion and could provide a scientific reference for wave erosion control and the ecological construction in the WLFZ.

Research on the Classification of Concrete Sulfate Erosion Types in Tumushuke Area, Xinjiang

Tumushuke, a significant node of “the China–Pakistan Economic Corridor” and “the Silk Road Economic Belt”, is strategically located in the southern region of Xinjiang. Due to the widespread distribution of its salty soils, concrete construction safety is significantly compromised. The construction of this project used sulfate-resistant cement, which was costly to construct. Six groups with varying sulfate immersion concentrations were set up to perform sulfate erosion tests and sulfate freeze–thaw coupling tests, respectively, based on the survey of the distribution of sulfate concentration in the area. The Tumushuke area’s concrete erosion kinds were classified using a microanalysis of the degraded concrete. The findings indicate that the concrete primarily exhibits gypsum-type erosion when the sulfate concentration is greater than 20,000 mg/kg, ettringite–gypsum-type erosion when the sulfate concentration is between 15,000 and 20,000 mg/kg, and ettringite-gypsum-type erosion when the sulfate concentration is less than 15,000 mg/kg. The erosion product, carbon–sulfur silica-calcite, also occurs under sulfate freeze–thaw coupling. In the Tumushuke area, ettringite-type erosion damage is primarily found in low-sulfate areas in the southwest and a small portion of the northeast. In contrast, higher-sulfate areas in the central northward area are primarily affected by ettringite–gypsum and gypsum-type erosion damage. The results of this study can provide a basis for adopting different anti-sulfate erosion measures for engineering construction in different regions.

Soil erosion resistance of gully system under different plant communities on the Loess Plateau of China

AbstractGully erosion, considered as a type of intensive erosion, is the dominant source of sediment at small watershed scales in certain environments. Variation of vegetation may result in the changes in near soil surface characteristics, which likely further affect the resistance of gully systems to erosion. However, the potential effects of near soil surface characteristics of plant communities on resistance to erosion are still unclear in gully systems. This study was performed to investigate the variations in resistance of gully systems to erosion under different plant communities and to identify the dominant influencing factors leading to these variations on the Loess Plateau. Five typical plant communities (two grasses, two shrubs and one forest) that distributed on different gully systems were selected. Six hundred undisturbed soil samples collected from different sites of gully systems were subjected to detach by overland flow under six different shear stresses (6.66 to 15.02 Pa). The results showed that the mean soil detachment capacity of gully systems covered by grass and shrub communities was 0.15 and 0.37 times to that of gully system covered by forest. Compared to forest gully systems, rill erodibility reduced by 29.8% to 85.6% for the other four plant communities. The relative rill erodibility of different vegetation communities generally increased from grass to shrub and forest communities. The critical shear stress of forest gully system was 58.7% and 63.8% of gully systems covered by grass (6.22 Pa) and shrub (5.73 Pa) communities. Bulk density, soil cohesion, water stable aggregate, root mass density, and the thickness of biological soil crust were the dominant factors affecting the resistance of gully systems to soil erosion. Rill erodibility decreased logarithmically with increasing soil cohesion, water stable aggregate and root mass density. Critical shear stress increased with the increase of soil cohesion and root mass density as a power function, and linearly with the increase of water stable aggregate. These results show how vegetation can mitigate against the erosion induced by concentrated flow in relatively stable gully systems.

Revegetation Changes Main Erosion Type on the Gully–Slope on the Chinese Loess Plateau Under Extreme Rainfall: Reducing Gully Erosion and Promoting Shallow Landslides

AbstractExtreme rainfall events pose a severe challenge to soil and water conservation, even in areas with high vegetation cover on the Loess Plateau. In this study, the artificial extreme rainfalls with cumulative rainfall of 270 mm and intensity of 60 mm · hr−1 were conducted on in‐situ experimental plots (20 × 2.5 m) on a loess gully–slope with gradients of 35°–40° that were treated with different grass coverage: (0%, 30%–40%, 70%–80%, >90%). The ephemeral gully/rill and shallow landslide occurred in plots were analyzed. Revegetation changed the erosion type on gully–slope, reducing gully erosion but promoting shallow landslide due to the change from infiltration–excess runoff to saturation–excess runoff. Under grass coverage of >90%, over 95% of rainfall seeped into the soil, and subsurface flow was generated due to the lower saturated hydraulic conductivity of underlying soil, which increased the possibility of landslides. The average erosion rate (0.36–3.29 g · m−2 min−1; no obvious erosion) in plots with 70%–80% coverage was 95.5% lower than that in bare land plots (27.8–47.5 g · m−2 min−1; ephemeral gully erosion), while due to landslides the average erosion rate in plots with >90% coverage (135.1–184.3 g · m−2 min−1) was 86.5 times higher than that in plots with 70%–80%. For grass, a coverage of 70%–80% was most effective in preventing soil erosion, controlling gully erosion and preventing landslides under extreme rainfall. These results deepen the understanding of the complex relationship between vegetation, gully erosion, and landslides in ecologically sensitive areas.

Aspects of Loco-Description in J. M. Coetzee’s Disgrace

The term “topography” describes a landscape’s structural elements and how they interact with the surrounding area. It focuses on the connections between the natural and constructed ecosystems and how human activities affect the environment. The history and ecological health of a region can be inferred from its topography. For instance, a location’s topography may reveal whether it has seen erosion, deforestation, or other types of ecological disturbance. Ecologists can better understand how environmental changes affect the landscape and its inhabitants by studying the topography of a certain location. John Maxwell Coetzee was a famous South African writer who tells us about these landscapes, climates, and other ecological aspects flawlessly in his novel Disgrace. John Maxwell Coetzee was popularly known by his initials, J.M. Coetzee. Coetzee was born on February 9, 1940, in Cape Town, South Africa. This paper studies the aspects of loco-description in J.M. Coetzee’s Disgrace.

Analysis of directions for application of artificial intelligence systems in soil condition analysis

The most significant characteristics of the soil are water-physical, biological and other properties, by influencing which it is possible to increase the productivity of agricultural crops. Analyzing various soil characteristics is a very labor-intensive and expensive process. The authors reviewed research on the use of artificial intelligence systems in the field of soil analysis. The purpose of the study is to analyze research on the use of artificial intelligence systems in the field of soil analysis. The article presents an analysis of artificial intelligence systems based on artificial neural networks (ANN), adaptive neuro-fuzzy inference system (ANFIS), support vector machine (SVM), multiple regression (MR) methods, particle swarm algorithm (PSO) and also their ensembles (various combinations). The use of these systems (their models) makes it possible to predict various types of soil erosion, predict soil temperature and moisture depending on various conditions, and also predict such complex indicators as the cation exchange capacity of the soil. The scope of application of artificial intelligence systems is to increase the awareness of managers and specialists of agricultural organizations and industry management bodies about various soil characteristics. This, in turn, allows you to make optimal decisions on various agricultural activities. Artificial intelligence systems can process significant amounts of data with high accuracy and speed compared to humans, which makes it possible to more effectively analyze many factors affecting the condition of the soil. The use of artificial intelligence systems can significantly reduce the cost of analyzing various soil characteristics and is a necessary condition for the use of precision farming systems.

Amphiboles of Alkaline-Ultrabasic Rocks from North-Western Part of the Ukrainian Shield

Different magnesian amphiboles — pargasites, Ca-Na- and alkaline ones (richterites, Mg-kathophorites, Mg-taramites, Mg-riebeckites, Mg-arfvedsonites and intermediate varieties) of alkaline-ultrabasic rocks (hypabyssal intrusions and dikes) from North-Western part of the Ukrainian Shield are studied and analyzed (mainly microbe method). Some pargasites and richterites are characterized by increased or high TiO2 contents (2.9-3.2%). In studied region more enriched in iron and titanium amphiboles (ferri-kaersutites) rarely occur too in veins rocks of essexite composition. Chemistry of amphiboles depends on types of rocks and erosion of their intrusions. Low aluminian and alkaline amphiboles are characteristic for at least eroded intrusions (dikes) whereas in more eroded and more crystallized hypabysal intrusions amphiboles with higher aluminium of pargasite composition form. Such diversity of studied amphiboles is caused by composition of alkaline-ultrabasic melts and some different depth of their crystallization.

A cockle-induced bioturbation model and its impact on sediment erodibility: A meta-analysis

Modelling the dynamics of an estuary and the evolution of its morphology requires a process-based description not only of the physical processes, but also of the influence of benthic fauna on sediment characteristics at ecosystem scale. A meta-analysis was tested as an approach for modelling the effect of bioturbation exerted by the cockle Cerastoderma edule on sediment erodibility. Six different erosion flume datasets were collected to ensure a broad range of experimental conditions including bed shear stress, population characteristics, and sediment composition. First, a model was built to describe the biogenic fluff layer created by C. edule activity in relation to (i) bioturbation activity using the population metabolic rate [mW·m−2] as a proxy for faunal metabolic energy, and (ii) the silt content [%] of the sediment. Second, different erosion models were compared by testing parameterization steps incorporating both erosion of the fluff layer and/or mass erosion of the sediment bed. Structural differences in the flumes and in the preparation of samples in the six different datasets makes it difficult to propose a single model that satisfactorily simulates all the data and encompasses both types of subsequent erosion, that of the fluff layer and that of the underlying consolidated bed. However, a generic model is proposed for the surficial fluff layer erosion covering a moderate range of bed shear stress (<1 Pa). This study shows that including several datasets covering a wide range of environmental conditions is a key to the robustness of this model, and that new insights can be gained by integrating the complexity of sediment features. We expect that this two-part model can be used in broad contexts in terms of cockle populations, estuarine habitats, and climatic conditions and can combined with various hydro-morpho-sedimentary models that include these biological effects.

Design of soil and water conservation techniques to minimize soil erosion on degraded land in Samarinda Tenggarong Axis Road

Soil conservation activities are aimed at tackling land degradation, especially soil erosion, which occurs rapidly. If there is human intervention, land will become more sensitive to the influence of water (rainfall) and gravitational forces. This study aimed to identify the types of erosion that occur on degraded land and design appropriate soil and water conservation techniques based on vegetative and physically degraded land conditions on the Samarinda-Tenggarong Axis road. The results of the documentation collected from each research site identified the type of erosion, and designed soil and water conservation techniques. This research is focused on the design referring to Permenhut P.04/Menhut-11/2011 and UU RI/37/2014. The results of this study showed that location 1 of the recommended technique is the vegetative technique and the manufacture of Water Sewerage, location 2 is the bench terrace technique, location 3 is the retaining wall technique, location 4 is the individual terrace technique, location 5 is the stone terrace/wall technique, location 6 is the stone terrace/wall technique, and location 7 is the garden terrace technique. The design of the soil and water conservation techniques recommended in this study is expected to have a positive effect on minimizing soil erosion on degraded land.

Clarification of the Regional Methodology for Calculating Potential Soil Flushing from Meltwater for the Northern Forest-Steppe of Central Siberia

Abstract—The need to verify, modernize and refine existing models for calculating potential soil flushing from the effects of meltwater is due to the small number of studies of this type of erosion in the forest-steppe zone of Central Siberia and, as a consequence, the inability to reliably determine how accurate the calculation methods are in their current form under these conditions. For the agricultural zone of the Krasnoyarsk Territory, a regional model has been developed for calculating potential soil flushing based on a Universal equation and the Instructions’ formula. This paper presents the results of its verification, performed using the results of the author’s field measurements of soil flushing from meltwater by measuring removal cones on agricultural lands of the northern forest-steppe of Central Siberia (Krasnoyarsk forest-steppe). A refined version of the Regional Methodology is proposed, adapted to local hydrometeorological conditions and representing the formula of this model with an added correction factor \(K,\) taking into account the influence of the previous autumn moistening of soils and the intensity of water flow to the soil surface during snowmelt. Refinement and adaptation of the methodology allowed to increase the accuracy of the results of its application by an average of three times compared to the original type of the model, the average error decreased from 0.3 to 0.11. The refined version of the Regional methodology was tested in the course of the author’s research of snow-fall soil erosion in the Krasnoyarsk forest-steppe.

Soil Erosion and Landslide Susceptibility Mapping in Western Attica, Greece: A Rock Engineering System Approach

Two of the eight main soil degradation processes with which soils worldwide are confronted are soil erosion and landslides. Specifically, landslides are a major threat in particular areas across Europe, often leading to serious impacts on population, property, and infrastructure. Regarding the abovementioned processes, the case study of the fatal Mandra flash flood (November 2017) in the Attica Region (Greece), which caused 24 deaths, and much infrastructure and building damage, is presented with the intention of assessing the relationship between soil erosion and landslide incidents. Investigations were executed from 2018 to 2022, and their outcomes were taken into consideration by the Technical Authority of the Attica Region. Soil erosion lines were delineated in a GIS and were validated using a previously generated regional Web-GIS landslide susceptibility map. The study presents soil erosion types from the Mandra fatal flash flood event and correlates them with already existing landslide susceptibility analyses for the Attica Region. The produced susceptibility map is a cartographic product on a regional scale (1:100,000) generated via a semiquantitative heuristic methodology named the Rock Engineering System (RES). The way in which both soil erodibility and landslide susceptibility maps were generated and validated could be the basis for proposing modeling approaches that can respond to new developments in European landslide policies.

Soil Erodibility Prediction On Oil Palm Land In Ujung Bandar Village, South Rantau District, Labuhanbatu Regency

&lt;p&gt;&lt;em&gt;There will be widespread damage to the land as a result of land degradation, particularly to forest land. Changes in land use from extremely durable vegetation to escalated agrarian land make the dirt all the more handily disintegrated. One of the deciding variables of disintegration is soil disintegration and soil cover vegetation. Soil erodiability is the typical measure of soil lost every year per unit of the file, while the land cover is helpful for safeguarding the dirt from the danger of harm by disintegration and further developing soil conditions. The exploration was done from October 2022 to June 2023. In January 2013, field sampling was carried out. The technique utilized in this study was the review strategy and the purposive examining technique. Choose three points of observation. Then, in the laboratory, data analysis and field observation. Assessment of soil erodibility is completed by taking soil tests, deciding soil structure, soil porousness in the field, and deciding soil surface and natural matter for examination in the research center. Distinguishing proof of disintegration by taking documentation of kinds of disintegration that alludes to references and realities tracked down in the field. To decide the worth of erodibility (soil aversion to disintegration) utilizing a nomograph (soil erosibility). Results of the Study Soil erodibility on oil palm land in the Urung Kompas Village was low to medium, ranging from 0.17 to 0.26. The research site on oil palm land in the Urung Kompas subdistrict has five types of erosion: trench erosion, splash erosion, sheet erosion, furrow erosion, and landslides.&lt;/em&gt;&lt;/p&gt;

Examining the impact of the inter-coarse void ratio (ICVR) on suffusion susceptibility and erosion prediction model

Suffusion, one of the primary types of internal erosion, preferentially erodes fine grains inside the skeleton of coarse particles due to interstitial permeability. The occurrence of suffusion damages earthen dams and affects the living environment around these structures. To avoid the effect of suffusion, many previous studies in the literature have investigated physical parameters influencing suffusion triggers or predicted suffusion potential. Yet, the precise impact of physical parameters, namely the inter-coarse void ratio (ICVR), on suffusion susceptibility was not considered. Thus, the crucial objectives of this article are devoted to investigating the effects of ICVR on suffusion susceptibility. The results show that suffusion susceptibility decreases until the minimum value at ICVR is 1.1 before increasing again. In addition, models for erosion prediction were proposed based on two physical parameters: ICVR and grain size distribution, which are easily determined in the laboratory.

Accommodating uncertainty in soil erosion risk assessment: Integration of Bayesian belief networks and MPSIAC model

Accommodating uncertainty stands as one of the most salient challenges in the development of soil erosion assessment tools. We presented a novel approach integrating the Modified Pacific Southwest Inter-Agency Committee (MPSIAC) model and Bayesian Belief Networks (BBNs) to assess soil erosion in a region of western Iran. The soil erosion status was reckoned based on the nine factors of MPSIAC. We utilized BBNs to produce a causal model for soil erosion, with output probabilities being validated through re-evaluation and sensitivity analysis. We identified erosion types, geological formations, run-off, soil erodibility, soil permeability, soil characteristics, and precipitation intensity as the main determinants of soil erosion. A significant, positive correlation existed between the erosion rate derived from MPSIAC and BBNs model in all land-use/covers over the work units. Overall, this study highlighted the potential of BBNs as a supportive tool for soil erosion prediction as well as a relatively simple and updatable soil erosion model for dealing with the diagnostic, scenario, and sensitivity analysis. Considering the increasing incidence of soil erosion, the BBNs model proposed in this study can be extended to a variety of ecosystems that are subject to soil erosion and changes in the probability of its causal factors.

The base plate orientation angle: a plain radiographic technique for designing the base plate’s inclination in reverse shoulder arthroplasty

Superior inclination of the base plate in reverse shoulder arthroplasty (RSA) is underestimated and may lead to major setbacks in terms of functional outcomes due to the altered biomechanics. Joint instability, scapular notching, and loosening of the glenoid component are considered the most serious sequelae. Therefore, a thorough preoperative radiological assessment of the affected shoulder joint and customized design of the prosthesis according to the glenoid morphology are decisive and directly correlated to the outcome. In this article, we propose a simple radiographic technique to assess the inclination of the glenoid preoperatively, which identifies the need for intraoperative correction. One hundred inconspicuous shoulder radiographs were included in the control group (CG) to define the normal ranges of the base plate orientation angle (BOA) and the base plate correction angle (BCA). Further, both angles were measured on 2-dimensional (2D) computed tomography scans of patients with proximal humerus fractures as well as radiographs, 2D and 3-dimensional (3D) computed tomography scans of patients with cuff tear arthropathy who underwent RSA between 2018 and 2021. The interobserver reliability among three independent testers was evaluated by calculating the intraclass correlation coefficient. In cuff tear arthropathy cases, the BOA and BCA measurements on different imaging modalities were compared using the Wilcoxon test. Possible variations of both angles' values based on glenoid erosion types, according to the Favard classification, were also investigated. Regardless of the imaging modality used, the interobserver reliability was excellent among three independent observers. In the CG, the mean BOA and BCA values were 118°±6° and 17°±5°, respectively. The mean corrected BOA values of the CG and fracture group were 136°±5° and 140°±5°, respectively. In contrast to the BCA values, the BOA measurements on radiographs showed a statistically significant difference compared to those obtained on 2D- and 3D scans in the cuff arthropathy group. Further, both angles' values varied according to the extent and location of the glenoid erosion. The lowest mean BOA and highest mean BCA values were observed in cases with Favard glenoid type E3. The BOA and the BCA are reliable tools proposed to aid in precisely positioning the glenoid component in RSA in the preoperative setting. Whereas, the BOA determines the inclination of the inferior glenoid segment, the BCA represents the extent of correction required to obtain a neutral inclination of the base plate. Glenoid type E3 of the Favard classification with superior wear is particularly susceptible to base plate superior tilt.

A systematic review of morphological models of salt marshes

Salt marshes are among the most important coastal wetlands and provide critical ecological services, including climate regulation, biodiversity maintenance, and blue carbon sequestration. However, most salt marshes worldwide are shrinking, owing to the effects of natural and human factors, such as climate change and artificial reclamation. Therefore, it is essential to understand the decline in the morphological processes of salt marshes, and accordingly, the likely evolution of these marshes, in order to enable measures to be taken to mitigate this decline. To this end, this study presented an extensive systematic review of the current state of morphological models and their application to salt marshes. The emergence of process-based (PB) and data-driven (DD) models has contributed to the development of morphological models. In morphodynamic simulations in PB models, multiple physical and biological factors (e.g., the hydrodynamics of water bodies, sediment erosion, sediment deposition, and vegetation type) have been considered. The systematic review revealed that PB models have been extended to a broader interdisciplinary field. Further, most DD models are based on remote sensing database for the prediction of morphological characteristics with latent uncertainty. Compared to DD models, PB models are more transparent but can be complex and require a lot of computational power. Therefore, to make up for the shortcomings of each model, future studies could couple PB with DD models that consider vegetation, microorganisms, and benthic animals together to simulate or predict the biogeomorphology of salt marsh systems. Nevertheless, this review found that there is a lack of unified metrics to evaluate model performance, so it is important to define clear objectives, use multiple metrics, compare multiple models, incorporate uncertainty, and involve experts in the field to provide guidance in the further study.

3D Finite-Element Numerical Failure Prediction of the E.T. Sea Stack Formation at Hopewell Rocks Provincial Park

Sea stacks, natural pillars of rock, are borne from shoreline rock cliffs and eventually collapse by wave action and other erosional processes. While historical instances of sea stack failure have occurred within Hopewell Rocks Provincial Park in New Brunswick, comprehensive assessments of sea stack stability and predictions of future failure are in their early stages. This study aims to forecast the future failure of the E.T. sea stack formation. Photographs taken from an unmanned aerial vehicle of the stack are used to construct a digital 3D geometry model of the formation using Structure-from-Motion photogrammetry. To determine the anticipated failure threshold, 3D finite-element (FEM) numerical models of the stack were developed in RocScience RS3 software. Erosion from wave action during high tides is simulated by progressively reducing the width of the stack within the erosion zone. The erosion rate is estimated, by comparing superimposed historical and current images of the stack, to be 19.19 mm/year perpendicular and 2.26 mm/year parallel to the shoreline. Two erosion types are modelled: symmetrical isotropic and asymmetrical anisotropic. Symmetrical isotropic models imply uniform erosion, while asymmetrical anisotropic models feature two orthogonal erosion rates with directional width reductions from the end of each erosion axis. Stability of the formation in the FEM model is evaluated using maximum shear strain, total displacement, yielded elements, and major principal stress values. The symmetrical isotropic models suggest a probable failure period between 101 and 127 years after 2021. The asymmetrical anisotropic models, however, indicate that failure could occur approximately 40 years earlier. Overall, failure of the stack experiencing asymmetrical anisotropic erosion seems to occur when the supporting pillar is about to erode under the stack’s centroid. With further validation, through additional modelling, the centroid of sea stacks has the potential to be used as a guideline for predicting sea stack failure.&#x0D; &#x0D;