Erosion Rates Research Articles

Designing, building and assessing a geomorphically reconstructed postmining landscape: A case study of the Santa Engracia mine, Spain

AbstractNew technology allows the reconstruction of postmining landforms using geomorphic design principles. It is important that such designs be evaluated and if needed, redesigned or reshaped so that soil loss is minimised and to ensure the landscape is geomorphically and ecologically integrated with the surrounding landscape. One tool to assess geomorphic landforms is to use a computer‐based landscape evolution model (LEM). LEMs allow different designs to be input and will highlight where erosion will occur and type of erosion (i.e. sheetwash, riling, gullying) as well as erosion rate. At the Santa Engracia abandoned mine (East‐Central Spain), postmining landscapes were designed using geomorphic principles (GeoFluv method and Natural Regrade software) and later constructed. The SIBERIA LEM was used to assess the erosional behaviour of these landscapes. Using suitable topsoil, vegetation and an organic blanket reduces erosion, and if vegetation can be established, the modelling demonstrates minimal gully erosion. The erosion forecast (5.3 to 6.3 t ha−1 year−1) is significantly lower than the initial surface (~350 t ha−1 year−1) using conventional (terraced) mine restoration. The predicted erosion rates and gullying are less than for the unmined (natural) Alto Tajo environment. Importantly, with the ability to spatially forecast gully location, erosion reduction measures can be undertaken. The method described here provides a robust assessment procedure and highlights the potential strengths and weakness of a design therefore supporting lower cost construction and repair with a higher chance of restoration success. The combination of geomorphic landform design and assessment using a LEM for this project (LIFE RIBERMINE) presents a new standard for mine rehabilitation in Europe.

Investigation of Friction and Wear Characteristics of Copper‐Containing Antimicrobial Stainless Steels at Low Temperatures

Experiments on friction and wear are conducted on copper‐containing antimicrobial stainless steel specimens and ordinary 304 stainless steel under a range of normal loads (20, 40, 60, and 100 N) and temperatures (23, 0, −60, and −120 °C). Using a white light interference 3D surface profilometer and a scanning electron microscope, the friction coefficient curves, wear mark surfaces, and friction mechanisms under varying friction conditions are analyzed. The results show that coefficient of friction (COF) and wear decrease with the decline regarding temperature and load, and the lowest value occurs at −120 °C. The copper‐containing antimicrobial stainless steel shows excellent tribological properties, with the COF gradually reducing from 23 to −120 °C. By contrast, the COF increases with increasing load. Additionally, tests and comparisons of standard 304 stainless steel under the same conditions demonstrate that the copper‐containing antimicrobial stainless steel shows enhanced tribological performance than ordinary 304 stainless steel, with a 31.2% lower erosion rate than standard stainless steel at −120 °C. Moreover, simulations and contrasts show that the copper‐containing antimicrobial stainless steel shows superior toughness and strength than ordinary stainless steel at low temperatures due to the presence of copper elements.

Climate resiliency of a tailings management facility: case study of Mont-Wright mine

ABSTRACT This study investigates the climate resiliency of the Mont-Wright mine tailings management facility (TMF) in Quebec, Canada, with a focus on tailings erosion and flooding. Ultra-high resolution (1 km) climate simulations of the global environmental multiscale (GEM) model, spanning the current (2001–2020) and future (2041–2060) periods, form the basis of this study. Comparison of GEM model outputs against gridded observation data suggests reasonable performance of the model in simulating TMF-relevant climate variables, giving confidence in the model. The analysis indicates potential increases in tailings erosion rates of up to 6% (0.01 g/m2s) for the future period due to elevated wind-induced shear stress. Floods, represented in terms of probable maximum flood, reveal future increases in magnitudes of up to 20% in summer/fall for durations of 12–72 h. Increases of up to 17% are projected for spring for the 72-h duration, with decreases noted for other durations due to precipitation efficiency reductions. The projected small increases in erosion rates, in absolute terms, are not deemed to be of any major concern. As for projected increases in flooding, Mont-Wright mine’s climate-change adaptation strategy, which is aligned with existing Quebec guidelines, seems reasonable to mitigate flooding impacts.

Noninferiority Randomized Clinical Trial: KIM Sling With Reusable Trocars Versus TVT Exact Sling

Importance The Neomedic Knotless Incontinence Mesh (KIM) sling with sterilizable trocars decreases medical waste versus midurethral slings with disposable trocars. Limited comparative data exist. Objective The aim of the study was to assess to the success of the retropubic KIM sling compared to the Gynecare TVT Exact sling. Study Design This was a single-center, randomized noninferiority trial comparing outcomes of 2 retropubic slings—KIM sling and TVT Exact sling—in women with stress urinary incontinence from August 2021 to May 2023. Primary outcome was subjective success at 6 weeks defined by a composite outcome of the response to the question #17 on the The Pelvic Floor Distress Inventory-20 questionnaire and no retreatment of stress urinary incontinence. Secondary outcomes included rates of urinary retention, mesh erosion, and reoperation for mesh complications. Sample size estimate based on noninferiority margin of 14%, equal success of 90%, alpha 0.05, and 80% power with a 20% dropout was 72 per group. Results Among 147 patients, 74 (50.3%) were randomized to KIM sling versus 73 (49.7%) to TVT exact. The rates of 6-week success were 68.5% for the KIM sling and 83.3% for the TVT exact with a risk difference 14.8% (95% confidence interval, 1.1–28.5). The KIM sling is not noninferior to the TVT Exact sling. There were no differences in secondary outcomes. Conclusions The KIM sling is not noninferior to the TVT Exact sling for success at 6 weeks based on a composite outcome score. This clinical trial is ongoing to assess outcomes at 6 months and 1 year. (Clinicaltrials.gov NCT04985799)

Testing of Shoreline Erosion Monitoring Methodologies for Heritage at Risk Sites: Pockoy Island, South Carolina, USA

Abstract We review shoreline monitoring methodologies used by members of the South Carolina Department of Natural Resources (SCDNR) Archaeology, Geology, and Wildlife Biology teams from February 2021 to December 2022 on Pockoy Island in Charleston County, South Carolina, USA. Our project objectives were to better understand the driving forces behind the landward movement of the shoreline (transgression), to apply new understanding to the rate of shoreline erosion of the island that directly impacts the Pockoy Island Shell Ring Complex (38CH2533), and to establish best practice for future community science monitoring efforts. Each member of our team used a different shoreline monitoring methodology (a nested methodology approach). Multiple unoccupied aerial vehicle (UAV)-derived orthoimagery datasets, on-the-ground transect measurements, and Arrow Gold real-time kinematic (RTK) unit measurements have been collected monthly following significant storms or king (perigean) tide events. Moving forward, the erosion transect approach tested within this project will serve as the foundation for community science monitoring at heritage at-risk sites in South Carolina. In this article, we introduce initial efforts in establishing a community science monitoring program in South Carolina that will influence future research, land management, and policy, and we propose how our research might be adapted for other sites at risk.

Dynamics of Shoreline Changes Along the Coast of Subarnarekha and Budhabalanga River Estuary, North Eastern Coast of India Using DSAS Technique: A Geospatial Technology Approach

ABSTRACTThe coastal regions represent one of the most significant environmental and economic resources, offering critical ecosystems that support biodiversity. Shoreline change analysis offers critical insights into coastal dynamics, providing trends in erosion and accretion, enabling effective coastal management and hazard mitigation. In the current study, shoreline change is assessed utilizing the Digital Shoreline Analysis System (DSAS) model for Subarnarekha and Budhabalanga river estuaries in Baleswar district, Odisha, India. The shoreline was extracted using multitemporal satellite images like Landsat‐5 and Landsat‐7 for the years 1991, 2000, and 2011. Similarly Sentinel‐2 and Landsat‐8 satellite imagery were used for the year 2022. The satellite data from 1991 to 2022 were processed using Envi, ArcGIS softwares and the shoreline is extracted for each year using band ratioing methods to demarcate shoreline. In the current research, the net accretion and erosion along the coast were analyzed using the GIS (geographic information systems) technique and the DSAS model. The four important statistical parameters of the DSAS model utilized in the study area are end point rate (EPR), net shoreline movement (NSM), linear regression rate (LRR), and least median of squares (LMS). The shoreline change analysis for the coast of Subarnarekha and Budhabalanga river estuary area from 1991 to 2022 reveals that 44% of the coast is under accretion, 7% is under stable coast, and 23% is under erosion. According to the findings, the coastal area of the recent study is both progressive and regressive in nature. For the study area, the average rates of shoreline accretion and erosion are 1.05 m and 0.45 m per year, respectively. The study gives information on erosion and accretion near the Subarnarekha and Budhabalanga river estuaries, which will aid in the development of an adaptive shoreline management strategy and coastal vulnerability assessment.

Estimating soil erosion in response to land use/cover change around Ghibe III hydroelectric dam, Southern Ethiopia

Soil erosion is a hazard in every part of the world. The small-scale farmers often grapple with low agricultural production and food insecurity. This study was conducted to estimate soil loss in response to land use/cover change in 1990, 2000, 2010, and 2020 around Ghibe hydroelectric III dam in Southern Ethiopia. The Revised Universal Soil Loss Equation (RUSLE) model was applied using a geographic information system (GIS). Digital elevation model with 30 m to determine topographic factor and supportive practice (P) factor, rainfall from the National Meteorological Institute to calculate the erosivity (R) factor, a digital soil map of the world for erodibility (K) factor, and Landsat 5TM images of 1990, 2000, 2010, and the Landsat 8 OLI of 2020 to determine trends of land use/cover change and the cover management (C) factor were employed. The raster layers of topography, cover management, rainfall erosivity, soil erodibility, and conservation techniques were processed and multiplied using the GIS platform. The overall accuracy of supervised classification was 89.89. The results showed that the percentage of cropland and built-up areas increased by 11.93 and 32.44%, respectively throughout the three study periods. Conversely, the proportion of forest land, grassland, bare land, and bushland declined by 8.2, 9.3, 10.13, 8.6%, respectively. The average annual soil loss rates increased from 30.95 t ha−1 yr−1 in 1990 to 43.85 t ha−1 yr−1in 2020. This is significantly higher than the maximum threshold rate of erosion for Ethiopian highlands (11 t ha−1 yr−1). The local government officers, non-governmental organizations, and farmers who are trained should strengthen watershed management techniques.

Land-Use-Change-Driven Erosion and Sediment Transport in the Yaqui River Sub-Basin (Mexico): Insights from Satellite Imagery and Hydraulic Simulations

Soil erosion and sediment transport are significant concerns in the Yaqui River sub-basin in northwest Mexico, driven by land use changes and environmental degradation. This study aims to evaluate erosion processes between 2000 and 2020 using a combination of satellite imagery and numerical simulations with Iber software (Version 2.5.2). The primary objective is to assess the impacts of land use changes, particularly the conversion of forest to grassland, on erosion rates and sediment transport. Satellite images from 2000 and 2020 were analyzed to detect land cover changes, while Iber’s sediment transport module was used to simulate erosion patterns based on the Meyer–Peter and Müller equation for bedload transport. Hydrological and topographical data were incorporated to provide accurate simulations of flow velocity, depth, and erosion potential. The results reveal a 35.3% reduction in forest cover, leading to increased erosion and sediment transport in steep areas. Simulation predictions highlighted areas with high future erosion potential, which are at risk of further soil loss if current trends continue. Flow velocity increased, contributing to riverbank destabilization and higher sediment yield, posing a risk to infrastructure such as the Álvaro Obregón Dam. This study underscores the need for targeted erosion control measures and sustainable land management practices to mitigate future risks and protect vital infrastructure in the Yaqui River Basin.

Evaluating the continued significance of dam-induced vigorous downstream channel erosion in the context of projected climate change: a case study from Peninsular India

ABSTRACT Although erosion has naturally been driven by rainfall patterns, human activities have increasingly influenced erosion rates in recent times. However, as climate change alters precipitation, future erosion control may once again depend primarily on climate. The primary goal of this investigation was to ascertain whether the issue of escalated erosion, typically linked to downstream dam effects, could diminish in significance due to projected climatic shifts later in this century. An erosion potential index (Ep), formulated as the ratio of the mass of sediment influx from upstream to the frequency of the sediment-carrying flow events, was computed on a tributary of the Godavari River, located downstream of a dam. Using the Soil & Water Assessment Tool (SWAT), virtual experiments were conducted to distinguish the impacts of the dam from projected climate changes on river geomorphology. Two control scenarios were created using the current climate data and simulated regulated and unregulated states of the basin. Employing climate projections and various mitigation scenarios (SSPs) for the 2060s and 2090s, this study estimated Ep values exclusively under future climatic conditions in an unregulated state of the basin. Results indicate that, in the unregulated state without the existence of the upstream dam, future climate impacts on erosion outweigh the current effects of the dam, underscoring the growing influence of climate on geomorphology. It suggests that existing structural interventions may lose their geomorphic significance in the face of future climate conditions.

Variability of Soil Aggregate Disintegration During Splash Erosion Under Different Circumstances

ABSTRACTThe duration of rainfall is a significant factor in the process of splash erosion. Nevertheless, there is a lack of comprehensive documentation regarding the extent and characteristic of soil aggregate disintegration resulting from raindrop impact during splash erosion. To examine the properties of the aggregate disintegration mechanism during various of splash erosion, three soil samples (S‐1, S‐2, and S‐3 labeled as the organic matter was 19.77, 31.70, and 26.83 g kg−1) were employed to simulated splash erosion under six durations of rainfall (5, 10, 15, 20, 30, and 40 min). Aggregates ranging in size from 1 to 5 mm were utilized in the preparation of test soils for different antecedent moisture contents (3%, 5%, 10%, and 15%). The result demonstrated that the slaking effect, as observed in the fast wetting of the Le Bissonnais method, is attributed to the sudden release of air entering the water, irrespective of the water immersion duration. Upon increasing moisture content, under fast wetting conditions, the mean weight diameter (MWD) values for S‐2 and S‐3 samples increased from 1.25 and 1.31 to 1.85 and 1.61, respectively. Subsequently, at a moisture content of 10%, the MWD decreased to 1.84 and 1.49 for S‐2 and S‐3 samples, respectively. In contrast, S‐1 sample exhibited an increasing trend from 0.34 to 0.93. The sensitivity of aggregates to disintegration from slaking (RSI) decreased by 0.58, 0.43, and 0.29, while mechanical impact (RMI) decreased by 0.23, 0.11, and 0.08 with increasing moisture content, respectively. The rate of splash erosion for the S‐1 sample exhibited an initial increase followed by a subsequent decrease as the duration of rainfall increased. The S‐1 sample, with the lowest organic matter content, exhibited the highest content of microaggregate content (< 0.25 mm) of splashed particles (referring to soil particles transported out of the splash area by raindrops), ranging from 31.62% to 65.57%. The content of macroaggregate (> 0.25 mm) in the residual soil (indicating soil particles that were left in the area affected by splashing) exhibited a gradual reduction as the duration of rainfall increased. As the soil reached saturation, the influence of physicochemical dispersion became more pronounced with the prolonged duration of rainfall. The forces of slaking and physicochemical dispersion predominantly disrupted > 1 mm aggregates, while the destruction of aggregates within the 0.25–1 mm range was insufficient. This study is valuable for understanding the splash erosion process and provides a scientific foundation for the improvement of soil erosion prediction models.

Numerical Simulation of Flow Fields and Sediment-Induced Wear in the Francis Turbine

Based on the solid–liquid two-phase flow model and the Realizable k-ε Turbulence model, numerical simulations of the sediment–water flow in the flow components of the turbine were conducted. The distribution of sediment-induced wear within the turbine was obtained by analyzing the sediment volume fraction (SVF) and the erosion rate. The results revealed that sediment-induced wear on the stay and guide vanes was primarily distributed along the water inlet edge of the stay and guide vanes. For the runner blades, wear was predominantly localized along the water inlet edge and near the lower ring. The sediment-induced wear patterns on these flow components were found to be consistent with the sediment volume fractions (SVFs) on their surfaces.

Vulnerability of kelp, Ecklonia radiata, to persistent nitrogen pollution and coastal darkening

Coastal darkening is expected to have pervasive impacts on benthic primary producers. However, the effects of nitrogen enrichment, an often-co-occurring stressor, on benthic primary producers and their functions is less clear. This study investigates the interactive effects of coastal darkening and nitrogenous eutrophication, including nitrogen source (NH4+ vs. NO3−), on the function of the kelp Ecklonia radiata. First, an in-situ experiment was used to assess the differential impacts of NH4+ and NO3− pulse enrichment on the photosynthetic performance and pH modulation capacity of E. radiata. Second, a laboratory experiment was used to assess the longer-term impacts of nitrogen enrichment under low-light conditions mimicking coastal darkening on service provisioning, including photosynthetic performance, pH modulation, nutrient uptake and growth. While pulse nitrogen enrichment had no impacts on the photosynthetic performance of E. radiata in-situ, persistent exposure to either NH4+ or NO3− acted as a stressor to sporophytes as indicated by elevated rates of dark respiration and lamina erosion and reduced photosynthetic efficiency and growth rates. Furthermore, low-light conditions elicited reduced photosynthetic capacity at saturating irradiance, which extended to a reduction in the extent of pH modulation, and significantly increased lamina erosion. While the two stressors appeared to act on distinct parameters, ultimately, both darkening and eutrophication directly reduced net primary production, especially when in combination. These results demonstrate the negative interactive effects of coastal darkening and eutrophication on E. radiata function, while suggesting a vulnerability of E. radiata to even moderate levels of persistent nitrogen enrichment. This vulnerability highlights the need to consider environmental conditions during kelp conservation and restoration, and when attempting to valorise kelp ecophysiology for nature-based solutions.

Cavitation erosion behaviour of MAB-CU4 alloy: influences of cavitation number, attack angle, time, and stand-off distance

Abstract The present study comprehensively examines the cavitation erosion behaviour of a manganese aluminium bronze alloy (MAB-CU4 alloy) as a function of several parameters (i.e., cavitation angle, cavitation number, time, and stand-off distance), particularly focusing on the influences of cavitation angle on the surface morphology and topography of the alloy. According to the design of experiment (Taguchi experimental design) analysis, mass loss increased with cavitation number and attack angle, while increasing the stand-off distance resulted in a decrease in mass loss and an increase in the surface area affected by cavitation erosion. Cavitation erosion behaviour was most affected by the cavitation attack angle, with the cavitation attack angle contributing 69.1% to total erosion, according to variance analysis. At 90° cavitation attack angle, MAB-CU4’s erosion rate was 64% greater than that at 30°. Scanning electron microscopy and optical profilometry revealed that cavitation erosion damage at 90° occurred mostly in the grain interiors as cavitation pits due to severe plastic deformation and surface corrosion, whereas pit formation was restricted around the hard secondary phases at the grain boundaries. At 30°, deep cavitation pits were limited, the erosion crater expanded, and the number of pits was reduced. Overall, finer microstructures with more grain boundaries and secondary phases may improve cavitation erosion resistance at 90°. The present study is the first to comprehensively capture erosion damage at the microstructural scale and analyse the impact of microstructural features on the erosion damage during the cavitation erosion of MAB-CU4 alloy.

Study on the resistance of basalt fiber concrete to erosion of building structure by wind gravel flow

Concrete structures in the windy regions of the Gobi face constant erosion from wind gravel flow, leading to severe surface damage and significantly reduced durability. This paper investigates the erosion resistance of basalt fiber (BF) concrete under various erosion conditions using the air-flow sand injection method. The results indicate that adding 0.15% BF to concrete reduces its erosion rate by 20.7% to 21.5% compared to concrete without BF. Therefore, a BF content of 0.15% provides optimal erosion resistance for the concrete. The correct amount of BF bonds tightly with the cement mortar, forming a mesh structure inside the concrete that absorbs the kinetic energy of gravel impacts. The concrete erosion process can be divided into an early accelerated phase and a later stabilized phase. Throughout these phases, the erosion rate of concrete increases with the erosion angle (EA), erosion wind speed (EWS), and gravel flow rate (GFR). In particular, the erosion rate of BF15 concrete increased by 35.6 to 46.4mg/cm² when the EA changed from 15° to 90°. Notably, surface damage from low-angle erosion mainly consists of cut scratches, while high-angle erosion primarily results in erosion pits. As the grain size of the eroded gravel increases, the erosion rate of the concrete decreases. However, when a single large gravel particle impacts the concrete, it creates a larger and deeper erosion pit. Furthermore, the erosion rate of BF concrete exhibits a strong negative linear correlation with its mechanical properties, with an R² value exceeding 0.88. Moreover, erosion reduces both compressive and splitting tensile strengths of concrete. For BF15 concrete, however, the decreases are minimal: compressive strength drops by just 1.2MPa, and splitting tensile strength decreases by only 0.2MPa. Building on Bitter and Neilson’s theoretical erosion model, an improved erosion model for BF concrete has been developed under wind gravel flow. This model incorporates the BF mixing factor and particle size function while considering other erosion parameters comprehensively. The enhanced model provides a theoretical foundation and scientific basis for safeguarding concrete structures in Gobi wind-prone regions.

A New Correlation for Estimating Solid Particle Erosion in Elbows

Solid particle erosion prediction models have been developed previously based on limited data and without consideration of uncertainties involved in measurements. In this study, a new correlation is developed to estimate the maximum erosion rate caused by solid particles in standard elbow geometries. The novel development process of this correlation includes uncertainty estimation of erosion measurements. In order to estimate uncertainties in an erosion database, it is imperative to have a model that could be used to calculate accurate erosion values to have reliable references. For this purpose, a database of repeated erosion measurements for gas-sand flows at low-pressure collected by previous researchers is used that includes standard elbow geometries with 0.0762 m and 0.1016 m internal pipe diameter, sand particles with mean diameters of 75 and 300 μm. Then, the erosion values in this database are adjusted to agree with physical behaviors expected in erosion process. Finally, based on the adjusted erosion values, a new correlation is developed that accounts for important paramters such as pipe and particle diameters, and gas velocity. The results and comparison of this new model with other correlations/models in the literature show that this correlation performs very well in predicting solid-particle erosion values for elbow geometry with a RMSE value of 7.96E-02 mm/kg. The effect of superficial liquid velocity is also investigated and modeled based on a database of gas-liquid-sand erosion and the correlation is updated for predicting erosion in two-phase flow conditions. Furthermore, CFD results for higher pressure fluids and larger pipe diameters of 0.1524 m and 0.2032 m and mean particle sizes of 25, 75, 150 and 300 μm, are used to further develop and validate the correlation for larger pipe size and high-pressure fluids flows. In summary, three correlations have been developed in this research; one for low-pressure flows with application in uncertainty estimation, one for predicting erosion in two-phase flow conditions, and one for cases with larger pipe diameters or high-pressure fluids.

A Hydraulic Gradient and Stress-Controlled Erosion Apparatus for Assessing Soil Internal Erosion

Abstract Among the four dominant mechanisms of internal erosion, suffusion appears as one of the most complex. It is indeed the result of the combination of three processes: dislodgement of fine particles, transport of them, and filtration of some fluidized fine particles. These processes depend on the soil’s stress state and on the hydraulic gradient path. Thus, to ensure the repeatability of the suffusion test and to study with accuracy the influence of the aforementioned parameters, a new apparatus was developed. This apparatus is designed to test specimens under a vertical downward flow in hydraulic gradient controlled condition while controlling the confining pressure and the stress deviator, which can be either positive or negative. Ten tests on one cohesionless soil were performed in triaxial conditions, with the same mean effective stress and four different values of stress deviator. To compare with conventional suffusion results, one test is also performed in rigid wall conditions. For all performed tests, the same hydraulic gradient path was applied and particular attention is paid to the repeatability, which implies control of each test step. At the end of each test, the specimen was divided into four layers to measure post-suffusion grain size distributions. The time evolutions of the hydraulic conductivity and the erosion rate permit to identify four different phases. Each phase is characterized by two methods: one based on the hydraulic gradient and the second based on the expended energy by the fluid. The results show the great influence on the suffusion kinetics of the preferential flow paths, which localize in the body of the specimen in triaxial conditions and on the circumference in rigid wall ones. Under a constant mean effective stress, the effect of the stress deviator on the suffusion kinetics appears limited, for the tested soil and shear stress ratios.

Erosional Response to Pleistocene Climate Changes in the Brazilian Highlands

AbstractPlio‐Quaternary climatic changes are considered to be a key driver of landscape evolution, but many unresolved questions remain, such as the extent of the impact of major climatic shifts such as the Mid‐Pleistocene Transition (MPT). Various geochronological methods are available to infer changes in surface processes over the Plio‐Quaternary, and Terrestrial Cosmogenic Nuclides (TCN) have proven to be one of the most efficient tools to reconstruct paleo‐denudation. Implementing these approaches requires very specific conditions, such as well‐preserved and extensive sediment sequences. Developing alternative methods to document the evolution of denudation is thus of major interest to retrieve information on the evolution of denudation in places where recent detrital sediment records are absent. We explore the evolution of landscape erosion over a 1 Ma timescale in an intra‐cratonic setting, the Espinhaço mountain range (Brazil), with a new data set of detrital cosmogenic nuclide concentrations (26Al–10Be). We observe a systematic disequilibrium in the 26Al/10Be ratio, which we interpret as resulting from the combination of soil mixing and a significant increase in the intensity of surface processes, close to the MPT. We discuss the different scenarios with respect to available local and global data concerning the relationships between climate evolution and erosion over this time period. Our results have important implications for the interpretation of the denudation rates derived from TCN concentrations under steady states assumption, in landscapes with low erosion rates, which have a long memory for surface processes history.

Contrasting physical erosion rates in cratonic catchments: The Ogooué and Mbei rivers, Western Central Africa

We measured the long-term physical denudation of the Ogooué River catchment using 10Be produced in situ by cosmic rays. These measurements are averaged over 25–200 ka (average 40 ka), depending on the physical denudation rate. The denudation rate of the Ogooué River catchment is slow (38 t/km2/a, 15 m/Ma), slightly higher than in Equatorial West Africa (from Senegal to Angola, 26 t/km2/a, 10 m/Ma). Physical denudation and chemical weathering fall within the same order of magnitude. Thus, although low, there is substantial chemical weathering compared to physical denudation, that likely contributes over 30 % of the total denudation.Denudation rates are spatially variable (from 10 to 60 t/km2/a) within the large Ogooué River catchment. Over the long term, physical denudation and chemical weathering roughly match, except in the Batéké Plateaux area, because the plateaus are made up of already weathered detrital material and therefore their modern flux of solutes is very low (∼9.5 t/km2/a). The spatial distribution is similar to the one described in the work of Moquet et al. (2021) on the basis of solute fluxes, i.e. the southern part of the catchment is denuding twice as fast as the northern part. We show here that the whole picture did not vary much since 100 ka, as shown by both methods which give consistent results. Faster denudation in the southern part of the catchment may be related to more uplift than in the northern part caused by the southern African “superswell”.

Long-term coastal dynamics: The evolution of a mixed sediment mega-nourishment consisting of colliery spoil

Mega-nourishments, where large volumes of sediment are deposited on coastlines, are increasingly employed to manage shoreline erosion, yet our understanding of their long-term behaviour is limited by the fact that most current schemes are less than 15 years old. However, on the County Durham coast, 39 million m3 of coal spoil was tipped onto beaches between the late 1800s and 1993, acting as a de facto mixed sediment mega-nourishment. Our findings reveal key insights into the long-term dynamics of mega-nourishment schemes, including evidence of effective sediment dispersal around headlands into normally disconnected units of coast. Following cessation of tipping, shorelines retreated up to 12 m yr−1, with 150 m overall retreat in 12 years. Subsequently, retreat slowed but the present-day shoreline remains seaward of its 1860 position and is subject to ongoing coastal recession. We document significant fining of the deposited material in the years post deposition through abrasion and chemical breakdown. Furthermore, we show that the highest erosion rates now occur downdrift from the initial dump site, indicating that nourishment impacts migrate through time. These findings highlight the need for holistic and adaptive management approaches to mega-nourishment schemes, showing the behaviour of the nourishment to continually change in both location and magnitude as the system evolves. We demonstrate that mixed sediment mega-nourishments can be a cost-effective and durable solution to mitigate erosive losses, even in the absence of a planned approach to the location or composition of deposited sediment. Our results suggest that lessons from this historical intervention can inform the design and management of future mega-nourishment schemes, particularly in mixed sediment environments.

The Application of Information Theory to Interpret Shore Platform Erosion Rates

Advancements in information physics have recently introduced the application of information theory to investigate physical systems. The behaviour of erosion at the granular scale is to date still a complex system to unpack, and therefore geomorphology research requires novel approaches to better inform the interpretation of temporal and spatial erosion patterns at different scales. This paper applies information theory concepts to re-evaluate erosional data that were measured on limestone surfaces of two shore platforms in Malta with a traversing micro-erosion meter (TMEM). By representing erosion rates through their information content using a Box-Cox style transformation of the raw data (application of an inverse normal distribution function to fractionally ranked data), it is possible to identify points and measurement periods that contribute to a disproportionately large share of unexpected erosion rates that could provide more insight into the causes of erosion rates. Despite the variations in the information content from erosion rates at individual measurement points, most points consistently contribute to a similar amount of information. These findings illuminate the importance of considering the informational value of erosion data to further understand the underlying physical processes and potentially improve predictive models.