Effects Of Erosion Research Articles

Cyanobacterial biocrust alters soil physical properties reducing soil erosion and aerosol production.

Aerosol emission by wind erosion in the arid and semi-arid areas of the world, is of environmental and health significance. Different methods have been used to mitigate aerosol emission among which the biological methods may be the most efficient ones. Although previously investigated, more research is essential to determine how the use of exopolysaccharide (biocrust)-producing cyanobacteria may affect soil physical properties. The objective was to investigate the effects of the cyanobacteria, Microcoleus vaginatus ATHK43 (identified and registered by the NCBI accession number MW433686), on soil physical properties of a sandy soil 15, 30, 60, and 90 d after inoculation. The effects of cyanobacterial biocrust on soil properties including shear strength, soil resistance, aggregate stability (mean weight diameter (MWD) and geometric mean diameter (GMD)), and wind erosion were determined in trays using a wind tunnel. Cyanobacterial inoculation significantly increased MWD (0-1cm depth, from 0.12mm to 0.47mm) and GMD (from 0.3 to 0.5mm) after a period of 90 d. Biocrust production significantly decreased soil erosion from 55.7 kgm- 2 to 0.3 kgm- 2 (wind rate of 50 kmh- 1), and from 116.42 kgm- 2 to 0.6 kgm- 2 (wind rate of 90 kmh- 1) after 90 d. In conclusion, cyanobacterial biocrust can significantly improve soil physical properties in different parts of the world including the deserts, and reduce aerosol emission by mitigating the destructive effects of wind erosion on soil physical properties.

Stressful exit of B2B executives and their impact on firm performance: Contingent effects of erosion of status, diminished social support and cohesiveness

Being fired is stressful. While unpleasant for all concerned, what if the person being sacked is a high-level B2B executive and a poor performer? What kind of impact does this exit have on co-workers, customers—and ultimately on a firm's performance? This research examines all these aspects, and introduces three moderators of C-suite dynamics in one framework. These are erosion of status, diminished social support, and group cohesiveness. And by applying job demands-resources theory, we are able to explain organizational stress. Our results show that when poor-performing executives are permanently let go, companies actually see a sacking sales bump of up to 6.3%. Results also show that upper echelon firings improve Tobin's Q, conditional on erosion in status (decreased by −5.9%), and cohesiveness (increased by +3.8%). To substantiate, we undertake over two dozen robustness checks. We also compare the implications when an executive's departure is forced or voluntary.

The effect of seasonal variation, flow conditions and erosion forces on suspended matter fluxes from boreal gypsum-treated agricultural fields

Like many other bodies of water, the Baltic Sea is facing a severe eutrophication problem, the excessive nutrient load currently originating primarily from agriculture. Gypsum treatment has shown promising results in reducing phosphorus and suspended sediment loads, especially in fine-textured soils, but its efficacy has not been investigated on catchment scale to any wide extent. This study examines the functionality of the gypsum treatment in an agriculture-dominated boreal catchment in the Archipelago Sea basin. The relation between turbidity and hydro-climatological factors was analysed during different years and seasons and the effect of stream erosion during different flow stages was investigated by applying 2D hydraulic modeling. A special focus was given to deviating winter conditions and freeze-thaw cycles.The results highlight the dependency of stream water turbidity on the discharge and the potential negative impact of the climate change-altered winter conditions of the hemiboreal climate zone on gypsum treatment effectiveness. The turbidity increased even more during high winter discharges, compared to other seasons suggesting that the more frequent freeze-thaw cycles and precipitation coming as rain during the unvegetated period increase erosion challenging the gypsum efficacy. Modelling results revealed that the increased erosional power during very high discharges caused settled material resuspension or stream bed or bank erosion leading to a cumulative increase in turbidity at downstream, an issue needing further research. Demonstrating the real and long-term effects of nutrient reduction measures requires catchment scale investigations over years, considering climatological factors. Based on this study, local and short-term investigations can potentially lead to over-simplified interpretations.

The erosive effect of digital economy on tax revenue: empirical evidence from urban panels in China

ABSTRACT This paper analysed the impact of digital economy on tax revenue. By using China’s urban panel data from 2011 to 2021, the empirical results demonstrate that the development of the digital economy has a negative impact on Tax-to-GDP ratio. The underlying reason is that the digital economy has not led to a proportional increase in tax revenue while increasing the tax base. In other words, it reduces the effective tax rate. After considering factors such as endogeneity, this conclusion still holds.

Examining enamel-surface demineralization upon exposure to acidic solutions and the remineralization potential of milk and artificial saliva.

The enamel surface may undergo demineralization due to exposure to acidic substances and the remineralization of the etched enamel is crucial to regain or maintain integrity. This study aimed to investigate the erosive effect of 10 acidic solutions on tooth enamel and the remineralization capacity of milk and artificial saliva by measuring surface roughness (Ra), enamel depth, and microhardness. A total of 80 bovine incisor enamel specimens were immersed in 10 different acidic solutions, including four different acidic drinks, three different citric acid solutions, and three different citric acid buffer solutions, for 1h. After demineralization, the specimens were immersed in milk and artificial saliva for 3h. Surface roughness, enamel abraded depth, and microhardness were measured before demineralization, in-between time intervals and after remineralization. Data were analyzed using Friedman and Kruskal-Wallis tests (p < 0.05). The results indicate a significant difference in surface roughness between the measurements taken at different time intervals, particularly between the baseline and after 1h demineralization. Also, the specimens immersed in CAB1 exhibited greatest increase in Ra among other acidic solutions (Δ: 0.18 ± 0.07). Moreover, only the microhardness increased after remineralization (p < 0.05). Enamel demineralization using various acidic solutions revealed increased Ra and enamel abraded depth, and decreased microhardness. The use of remineralization agents, milk and artificial saliva, demonstrated an increase in microhardness. This study provides insights into the effects of different acidic solutions and potential remineralization agents on tooth enamel.

Characterization of microstructural evolution of asphalt due to water damage using atomic force microscopy

Water erosion significantly impacts the microstructure of asphalt, which in turn affects the macroscopic performance of asphalt mixtures, such as reducing the adhesion between asphalt and aggregates as well as diminishing water stability. This study utilizes atomic force microscopy (AFM) to investigate the micromorphology, surface height distribution, nanosurface roughness, and microsurface energy of asphalt under different water immersion durations. Furthermore, it considers the influence of asphalt's penetration grade, oil source, and modifiers on the evolution of its microstructure. AFM analysis reveals that, with the exception of crumb rubber modified asphalt (PJ90/CR), the quantity and area of beelike structures in the asphalt decrease with increasing water immersion time. The surface height distribution of asphalt exhibits characteristics of an approximate normal distribution, with an increase in nanoscale heights over time due to the dissolution of surface components by water and physical erosion effects. Notably, the surface height of PJ90/CR and SBS modified asphalt (PJ90/SBS) is significantly lower than that of PJ90 before and after water immersion. Water damage causes asphalt surface particles to dissolve and re-aggregate, forming distinct nano-protrusions and pits, thereby increasing the asphalt's roughness. Among them, the roughness of SK90 are generally higher than those of SK70, with the average roughness (Ra) and peak-to-valley roughness (Rt) increasing by 28.93 % and 60.56 %, respectively, before immersion. Moreover, water damage leads to a decrease in the surface energy of asphalt to varying degrees, indicating that water more easily penetrates the asphalt film through adsorption and diffusion actions, altering its microstructure and, consequently, reducing its surface energy. The variations in the microstructure of SK90, Shell90, and PJ90 under different water immersion durations highlight the significance of oil source on asphalt performance.

Educational videos on erosion disseminated through social media for soil education

ABSTRACT Soil education plays an important role in preventing soil degradation processes by raising awareness among the population about the importance of this non-renewable resource. Using new educational technologies in teaching, such as educational videos and social media, can speed up communication and information. This article aimed to develop educational videos on the topic of erosion, posted on social networks, as a way of popularizing science. Four videos of a maximum of 7 minutes were produced, which were shown in the classroom and on Instagram (@saberessobresolos). In-class promotion reached nine undergraduate and postgraduate classes, totaling an average of 255 students. Metrics used for evaluation were polls and video engagement on the social network. Instagram metrics results indicated, in a period of 49 days, 1615 profiles had accessed the video. There was a reduction in this engagement in other publications, probably due to the variation in time, day of the week, and frequency of posts. The results of the surveys were positive for all the characteristics evaluated, with little disparity among the videos. On a smaller scale, negative feedback was observed, such as: the narration, running time, the translation into Brazilian Sign Language (Libras), and video captions. Approximately 81 % of individuals reported experiencing soil erosion effects, and 59 % had encountered issues as a direct consequence. The evaluation also indicated the videos’ ability to enhance knowledge is above 90 %, largely due to the dynamic and inclusive nature of this pedagogical approach, fostering genuine comprehension of the content, satisfaction in learning, and the ability to engage in meaningful discussions on the subject. Disseminating educational videos through social media ensured the democratization and widespread access to soil education, as it expanded reach and facilitated the exchange of knowledge between universities and society. The project fulfills its mission of producing and popularizing knowledge on soils, expanding scientific dissemination, making it more accessible, and contributing to recognizing the importance of conserving this resource.

Post-fire soil erosion: Two years of monitoring − First time detected implications between extremely intense consecutive rainfall events and erosion rates

The research was carried out in one of the most important suburban forests of Greece, after a wildfire (2021). The objectives include the estimation of the annual soil erosion, the effect of extremely intense and consecutive rainfalls on erosion process, the correlation among erosion, rainfall intensity and other factors. To monitor soil erosion in burned and unburned areas, erosion measurements were obtained installing silt fences. The results showed that the main factor affecting annual erosion is the presence or not of vegetation. Rainfall intensity is a major determinant of erosion, especially when it exceeds 6–7 mm/30 min. However, it was revealed that erosion does not increase significantly in burned areas, despite the increase of rainfall intensity. In unburned area the erosion was significantly increased, above a rainfall intensity threshold (>10 mm/30 min). For the first time, it was shown that in cases of two consecutive and very heavy rainfalls, the second and more intense rain caused significantly lower erosion than the first one. A 690 % average increase in R factor during the 2nd storm, showed an average decrease in soil erosion of 20 % (burned and unburned areas). The present study also revealed that the high increase of R factor in the 2nd post-fire year did not trigger a significant increase of soil erosion, since the extreme erosive events occurred very close to each other in time. These findings highlight that the use of R factor in RUSLE, to calculate the annual erosion in burned or unburned areas, detached from the respective field data establishment to validate the model, involves high uncertainties, which could possibly result in wrong erosion rates calculations. Researches and stakeholders, who use the R factor in erosion modeling, should previously examine in detail the exact dates of erosive events, before the implementation of the erosion model.

Tracing climate and human-driven erosional activity in the Transylvania lowlands (Central-Eastern Europe) during the Holocene

Erosion is a complex geomorphological process controlled by climate, soil and vegetation characteristics in addition to land-use. However, the interplay of these drivers is not fully understood. Here we present a 11.8 ka multi-proxy record of geochemical, mineral magnetic and grain size analyses from Lake Stiucii, in the Transylvania lowlands (CE Europe) documenting past erosional activity and the drivers of landscape change. We identify three major phases in the site’s development. The first, a lacustrine phase (11.8–10.9 cal ka BP), is characterised by open water conditions with significant river inflow and depicts a period of greater erosion under a less developed catchment vegetation cover. Between 10.9 and 4.6 cal ka BP, the lake became a wetland characterised by shallow water with a reduced drainage network under warmer climate and/or reduced rainfall. From 4.6 cal ka BP, a second lacustrine phase developed driven by enhanced stream flow and sediment input subsequently accelerated by land use change. On a millennial scale, the two significant changes in the lake-catchment system and erosion regime at 10.9 and 4.6 cal ka BP may reflect a response to fluctuations in large-scale atmospheric circulation patterns. The eight short-term erosional events identified at 10.6, 7.8 cal ka BP, between 4.4–4.1, 3.5, 3.0–2.5, 1.9, 1.5, 1.1–0.8 cal ka BP, overlap well-known climate events. However, from 4.6 cal ka BP the climate-landscape relationship is amplified by rising anthropogenic impacts. Our data provide critical information on the paleoenvironmental evolution of CE Europe’s lowlands and facilitate discussion of the effects of millennial and centennial climatic shifts as expressed in the local environment.

Comparative analysis of combustion characteristics and economy between air assisted combustion and oxy-fuel combustion in glass furnaces

The oxy-fuel combustion is an effective means to improve the high energy consumption, pollution, and economic cost of glass furnaces. In this paper, the combustion characteristics in the flame spaces of traditional natural gas/air assisted combustion glass furnace (GF-NAC) and reformed natural gas/oxy-fuel combustion glass furnace (GF-NOC) are analyzed and compared by means of numerical calculation. More importantly, a systematic quantitative comparative analysis is conducted on the economic performance of the two glass furnaces from the perspectives of fixed and operating costs. The results show that enhanced combustion performance of GF-NOC over GF-NAC is found with flames being extended across the entire width of the furnace in GF-NOC. A more uniform temperature distribution within the furnace is consequently accomplished in GF-NOC. The flame center temperature, the average furnace temperature, and the average glass surface temperature in GF-NOC are increased by 7.42 %, 1.17 %, and 7.96 %, respectively, compared to GF-NAC. Furthermore, a reduction in gas velocity by 50 % at the arch in GF-NOC is observed to mitigate the erosive effects of high-temperature gas flows on the furnace crown. According to the service life of glass furnace of 15 years, the GF-NOC can save 420 M (million yuan) (12.8 %) compared to the GF-NAC. Although the fixed cost of GF-NOC is 9.82 M (5.43 %) higher than that of GF-NAC due to the expenditure on oxygen production equipment, the difference is offset by operating costs. Compared to GF-NAC, GF-NOC can save operating costs of 28.7 M (15.87 %) per year.

Pore structure characteristics of artificial sand aggregate mortar

With the progressive depletion of natural sand, the substitution of natural sand with artificial sand as a construction aggregate has received significant attention. To analyzed the pore structure characteristics of artificial sand aggregate mortars, nuclear magnetic resonance (NMR) technology was utilized to analyze the distribution characteristics and dynamic changes of five types of aggregate gradation mortars, and fractal theory was employed for characterization. The study examined on the correlation between aggregate gradation and pore structure, fractal dimension, and assessed the connectivity of the pore structure. The results showed that: water-saturated samples were mainly composed of micropores and movable fluid pores after 28 days of hydration, while the micropores and clay-bound fluid pores dominated after 365 days of hydration. The formation of the pore structure in multi-aggregate-graded mortar is influenced by both the surface-to-volume ratio and aggregate packing density. At the same hydration time, lower porosity in water-saturated mortar results in increased non-homogeneity of the pore structure and a reduced permeability coefficient. Well-graded aggregate mortar has stronger resistance to hydraulic erosion, and the stronger the erosion effect of water will be with more developed pore structure.

Impact of Dust Source Patchiness on the Existence of a Constant Dust Flux Layer During Aeolian Erosion Events

AbstractDust emission fluxes during wind soil erosion are usually estimated using a dust concentration vertical gradient, by assuming a constant dust flux layer between the surface and the dust measurement levels. Here, we investigate the existence of this layer during erosion events recorded in Iceland and Jordan. Size‐resolved dust fluxes were estimated at three levels between 2 and 4 m using the eddy‐covariance method. Dust fluxes were found mainly constant only between the two upper levels in Iceland, the lower dust flux being often stronger and richer in coarse particles, while dust fluxes in Jordan were nearly constant across all levels. The wind dynamics could not explain the absence of a constant dust flux layer in Iceland. We show that the presence of stationary dust source patches in Iceland, related to surface humidity, created a non‐uniform dust layer near the surface, named dust roughness sublayer (DRSL), where individual plumes behind each patch interact but do not fully mix. The lowest dust measurement level was probably located within this sublayer while the upper ones were located above, such that there the emitted dust became spatially well‐mixed. This explains near the surface in Iceland, the more intermittent dust concentration, its low correlation with the dust concentrations above, and the richer dust flux in coarse particles due to their lower deposition contribution. Our findings highlight the importance of estimating dust fluxes above a dust blending height whose characteristics depend on the dust source patchiness caused by surface humidity or the presence of sparse non‐erosive elements.

The stability of foamed asphalt concrete based on different soaking conditions

The purpose of this study is to test the water stability of foam asphalt mixture under various immersion conditions. For this purpose, experiments were conducted on warm mixed foamed asphalt and traditional hot mixed asphalt. To evaluate its water stability, Marshall tests, immersion Marshall tests, vacuum saturation Marshall tests, and freeze-thaw splitting tests were conducted. Based on surface energy theory, the water damage mechanism of asphalt mixtures was analyzed. The research results indicate that due to the adverse effects of water erosion and pressure, the water stability of the two mixtures gradually decreases. Although the failure load value of warm mixed foamed asphalt mixture is slightly lower than that of hot mixed asphalt mixture, its water stability parameters still meet the specified requirements. Therefore, warm mix foam asphalt mixture shows satisfactory water stability under different soaking conditions.

Thermal fatigue behavior of the ZGH451 Ni-based superalloy fabricated by direct energy deposition in the temperature range of 900–1100 °C

In this study, a novel Ni-based superalloy, ZGH451, has been fabricated using direct energy deposition (DED). The thermal fatigue resistance of ZGH451 is systematically evaluated at 900, 1000, and 1100 °C, primarily focusing on the crack initiation and propagation behaviors. The results indicate that higher peak temperatures lead to earlier initiation and more rapid propagation of cracks. Cracks are initiated at the defects and grain boundaries in the vicinity of the notch, and different crack propagation mechanisms (γ' phase slip shearing, γ' phase distortion shearing, and γ' phase rafting shearing at 900, 1000, and 1100 °C, respectively) are the main reason for the different cracks propagation behaviors under the three temperatures. The main crack propagation paths are oriented at approximately 45° with respect to the build direction, suggesting activation of the {111}<110> slip system. Additionally, oxidation reduces the matrix strength and passivates the crack tips, leading to varying rates of crack propagation. At elevated temperatures, the synergistic effects of thermal stress and oxidative erosion are found to be the primary damage mechanisms of thermal fatigue. Overall, the proposed ZGH451 superalloy demonstrates exceptional thermal fatigue resistance, providing a crucial experimental reference for thermal fatigue in additively manufactured superalloys.

Leveraging the potential of third space faculty developers to foster individual and collective flourishing faculty professional identities in higher education

In the context of higher education, which is a complex environment of shifting landscapes, academic identity is perceived as being eroded, and new identities associated with hybrid roles abound. Flexible support mechanisms are needed to counter the destabilising effects of the recent erosion of tradition-bound structures. This study explores how an understanding of faculty professional identity might be used by faculty developers to inform individual and collective development initiatives and foster flourishing. Using a qualitative methodology, focus group discussions with faculty developers probe the potential utility of a measure of faculty professional identity. Utility is evaluated at three levels of practice: institutional, collective and individual. Findings demonstrate the potential for faculty developers, with their third space positioning, to play a pivotal role in guiding individuals and institutions as they navigate increasingly complex higher education contexts. Recommendations include recognising the strategic potential of faculty developers as institutional gatekeepers of sensitive data and enablers of collective flourishing. A data-informed, adaptive, person-centred approach to individual faculty development that delves into the being as well as the doing to facilitate individual flourishing is proposed.

Cavity Disinfection with Natural Agents and their Efficacy: A Review on Recent Literature

Abstract: The success of a dental restoration can be altered by the amount of residual bacteria present under the cavity which over time cause deterioration of adhesive cement by microleakage or secondary caries. Cavity disinfectant application on the cavity walls performs a cleansing action to decrease the bacterial load and improve the longevity of restorations. Although a wide variety of such chemical disinfectants have been in use, their cytotoxic effects have led to the increasing popularity of natural agents. These materials possess antimicrobial, antioxidant and anti-inflammatory properties, which effectively disinfect cavity walls while, at the same time, being cheaper, less toxic, and more patient-friendly. : Some of these agents have also been proven to improve the bond strength of resin to dentin by preventing collagen degradation and MMP inhibition. Propolis, aloe vera, chitosan, green tea, liquorice etc., are derived from parts of plants or animals and have been tested to be efficacious and, in some cases, superior to chemical alternatives without any erosive effect on dentin. : Although there is a lack of enough In vivo evidence to advocate the use of these products as an adjunct in dental therapy, recent studies have yielded promising results, which increases the scope for future clinical research. This review aims to highlight the properties and effectiveness of a few of such natural agents as potential cavity disinfectants.

Mapping and quantifying medium-term soil loss rates in mountain olive groves using unmanned aerial vehicle technology

Olive groves are one of the main agroecosystems in the Mediterranean region, but water erosion, aggravated by inappropriate soil management, is compromising the environmental sustainability of these crops. National and international public organisations, including the European Union via its Common Agricultural Policy, have acknowledged the problem and recognise the need to quantify the effects of this process. However, the variability of currently available short-term soil erosion measurements, together with limited understanding of the underlying processes, mean there is considerable uncertainty about the long-term effects of soil erosion. This paper presents an innovative procedure called SERHOLIVE4.0 designed to measure and model long-term soil erosion rates in olive groves, by means of structure-from-motion (SfM) techniques by which image information is obtained from unmanned aerial vehicles (UAVs). For the present study, the procedure was evaluated in mountain olive groves, where the erosion rate was calculated from historical surface reconstructions. Overall, this approach was found to be practical and effective. The method includes the following steps: [1] measure the current relief using UAV technology; [2] reconstruct the historical relief from field measurements; [3] calculate soil truncation (h) and obtain a soil erosion rate map; [4] determine the erosive dynamics of the slope and establish the relation between tree truncation, slope and mounds. The method we describe presents the following advantages:•it quantifies soil losses by reference to existing tree mounds;•it is straightforward to apply;•its application enhances the calibration of erosion models.

Four Years of Meander‐Bend Evolution Captured by Drone‐Based Lidar Reveals Lack of Width Maintenance on the White River, Indiana, USA

AbstractMeandering rivers experience fluctuations in width whenever riverbanks migrate in different directions or at different rates, which can be observed after individual floods. However, meandering rivers maintain approximately constant widths over decadal timescales. This implies some timescale below which width fluctuates as banks migrate independently, and above which width is maintained by a bank‐coupling process. This coupling is thought to occur either as point bar deposition events induce cutbank erosion (bar‐push), or as cutbank erosion events induce point bar deposition (bank‐pull). This coupling, however, has been challenging to observe in natural rivers due to limited event‐scale field data. We present results from a 4.5‐year campaign with 22 drone‐based lidar surveys of a single point bar and cutbank (∼0.35 km2 in area) on the White River near Worthington, Indiana, USA. The middle point bar experienced net erosion (5,400 m3), but net aggradation (17,100 m3) between 2019 and 2022 when including perennially submerged regions. This aggradation was less than the 35,700 m3 of cutbank erosion over the same period. Combined, we have observed widening (1.58 m/yr bend‐averaged; 3.08 m/yr near apex) over the study period as point bar deposition has not kept up with cutbank erosion. Finally, we suggest that the difference between bar‐push and bank‐pull as width‐maintenance mechanisms may not be resolvable by observing bend widening or narrowing alone without an advancement of current theory, such as determining a long‐term equilibrium width and measuring deviations relative thereto.

Estimating Wear Rate of Guide Vanes in High-Head Francis Turbines through Flow-Through Testing and DPM Simulation

Abstract The development of high-head water resources poses a significant concern due to hydro-abrasive erosion caused by entrained sediment particles. This issue is particularly prevalent in the muddy rivers of the Xinjiang region, China, where Francis turbines are commonly used. With increased soil erosion and rapid sediment transport, the erosion of Francis turbines, especially the guide vanes of high-head turbines, has become increasingly severe. The paper explores key factors that influence the erosion process caused by sediment-laden water. In addition to flow velocity and mud concentration, the properties of the sediment-laden water, such as hardness and size of sand particles, and the concentration ratio of sand particles with different hardness, also play a crucial role in the erosion process. The study is focused on analyzing the erosive effects of sediment-laden water on a high-head Francis turbine’s guide vane. The efficacy of the discrete phase model (DPM) as a simulation method for assessing wear on the guide vane is validated. This model helps analyze critical wear areas on the surface of the vane, enabling the identification of regions most severely affected by erosion due to sediment-laden water. By pinpointing these critical wear areas, the study provides valuable insights into the potential damage caused to the guide vane, thus contributing to better understanding and potential mitigation of erosion in similar turbine systems.

Sediment dynamics and geomorphology in coastal areas affect long-term abundance of waders

Millions of migrating and wintering waders depend on coastal areas and estuaries for feeding and to replenish body reserves. These habitats are dynamic, with changing intertidal flats and sediments due to natural and climate-driven processes. The aims of this study were to examine whether physical conditions of intertidal flats such as geomorphology and sediment compositions could explain abundance of wader species, and furthermore whether changes in these conditions over time influenced changes in abundance of waders. In addition to physical structures such as datum (level), slope and sediment composition of intertidal flats, dynamic variables connected to tidal cycles such as distance of the waterline from the coast and duration of water cover were included. Penetration of the sea floor was measured as a proxy for sediment composition. The study was conducted in the Danish section of the Wadden Sea during 1981–1986 and 2008–2009 with additional data from 2020. The focus was on 12 widespread wader species. PCA analysis revealed that wader species were distributed in relation to tidal cycles such as duration of water cover and the position of waterline and to the physical structures, datum, slope and penetration, in decreasing order. With regard to the physical structures, pairwise comparisons of distribution of waders species showed that mean datum (level) was significantly different for 51 pairs of species out of 66 comparisons, mean penetration values differed for 34 pairs, and mean slope differed for 26 pairs of wader species. Long-term changes of physical structures of transects revealed that changes of densities of 10 wader species were significantly correlated with changes per year in one or more of the physical structures: seven wader species were significantly correlated with changes per year of mean datum (level) of transects (Lapwing was positively correlated while Avocet, Golden Plover, Grey Plover, Dunlin, Bar-tailed Godwit and Redshank were negatively correlated), five species with mean slope (Oystercatcher, Ringed Plover and Knut were positively correlated and Grey Plover and Redshank were negatively correlated), and three species with mean penetration values (sediment composition) of transects (Avocet and Bar-tailed Godwit were positively correlated and Lapwing was negatively correlated). The study shows that long-term changes of physical structures of intertidal flats affected abundance of wader species. The results are important for interpretation effects of erosion and accretion of coastal areas as consequences of natural and climate driven processes such as sea level rise and coastal squeeze.