High Erosion Rates Research Articles

Soil Erosion Rates Via 210Pbex, 137Cs and USLE Model in El Rmel Watershed, NE Tunisia

ABSTRACTSoil erosion is a severe environmental and agricultural phenomenon which can be accelerated with climate change and land use, particularly in the Mediterranean region. In Tunisia, studies on the spatial distribution of erosion and deposition patterns can help to effectively implement soil and water conservation practices. Accordingly, the main objective of this research was to estimate soil erosion rates in two cultivated soils (SE1 and SE2), at El Rmel watershed of northeastern Tunisia. Three different time scales were observed via three tools, the 137Cs, the 210Pbex radioisotopes and the USLE model. The FRN's conversion mass balance model 2 (MBM2) was used to convert activities into erosion rates. Based on the 137Cs, 210Pbex, and USLE model, the mean erosion rates were, respectively, 37, 52, and 33 t ha−1 year−1, at the cereal cultivated SE1 site and 4, 9, and 6 t ha−1 year−1, at the olive tree cultivated SE2 site. It is supposed that the difference in time scale expressed by the three methods (100 years by 210Pbex, 60 years by 137Cs, and 40 years by USLE), may have had a notable impact on the discrepancy in estimated erosion rates. The mean farm slope for SE1 and SE2 were, respectively, 14% and 8% and tillage was through three operations per year. Furthermore, the cereal crops site characterized by steep slopes show much higher erosion rates. Consequently, planting olive trees will be very helpful in reducing soil erosion and will be of great impact either environmentally and/or economically.

Delayed environmental pollution caused by transient landscape storage - An example from the Lesser Antilles.

The strong pest pressure on intensive banana cultivation in the French West Indies led to the intensive use of chlordecone (an organochlorine insecticide) between 1972 and 1993. Due to its high toxicity for the population and the environment, many studies were conducted on the transfer of chlordecone over the last 20 years. However, most studies focused on the dissolved fraction of chlordecone, while the particle-bound fraction was understudied. Therefore, this study reconstructs pluri-decadal erosion rates (i.e. 1980-2023) and associated chlordecone particle-bound transfers from soil and sediment cores sampled in a cultivated headwater catchment (Saint-Esprit, Martinique). Based on sediment accumulation analyses in an agricultural reservoir, high erosion rates (i.e. 10 t ha-1 yr-1) were found in the investigated catchment during the study period, with values exceeding the estimated tolerable soil loss rate in tropical contexts (i.e. 2.2 t ha-1 yr-1). Based on the analysis of soil cores sampled along a banana plantation hillslope, this study highlights the formation of colluvial deposits with high levels of chlordecone contamination. When these areas are affected by erosion processes, this leads to massive remobilization of particle-bound chlordecone to water bodies. Indeed, in sediment sampled in the downstream reservoir, we observed a drastic increase in these transfers since 2006, synchronous with changes in agricultural practices. This study therefore highlighted the occurrence of legacy contamination at toeslope positions, which was estimated to potentially persist for 4000 to 11,000 years. Such a residence time highlights the need to implement changes in land management to effectively reduce erosion of agricultural soils, particularly in areas identified as "temporary deposition zones" for chlordecone contamination, in order to protect downstream water bodies from chlordecone transfer. To achieve this, agricultural practices that may increase soil erosion, such as herbicide application or intensive ploughing, should be minimized. Overall, this study improved our understanding of erosion and associated chlordecone transfers in tropical environments.

Sputtering yield and induced contamination of Kapton, PEEK and PTFE under xenon ions bombardment

Abstract In this article, we present the results of sputtering yield measurements of Kapton, PEEK and PTFE due to xenon ions bombardment. We measured these yield using the weight loss technique, for energies ranging from \qtyrange[range-units = single]{350}{800}{\eV} and incidence angles from \qtyrange[range-units = single]{0}{75}{\degree}. Polymers sputtering yield dependence versus incidence angle appears to be much lower than what we usually observe on other materials (such as metals). Furthermore, PTFE exhibits a very high erosion rate, which is two orders of magnitude bigger than Kapton and PEEK one. We also performed collection measurements using a quartz crystal microbalance (QCM) apparatus. Such method provides differential sputtering yields data which are key pieces of information regarding satellites contamination issues. We also computed the total sputtering yields obtained by this second method, and it appeared that they were much smaller than the ones measured previously by weight loss, specially for PTFE. This suggests that erosion products may be of different types (atoms, molecules) which are not all able to stick on a facing surface.

Evolution of the Contemporary Landscape: Relevance of Land Use Management Over Environmental Drivers of Soil Erosion

ABSTRACTWater erosion is the main soil degradation process in landscapes under human pressure. The assessment of soil losses according to biophysical factors is the key to understanding erosion processes. This study aimed to assess the biophysical and anthropological factors controlling the change in water soil erosion rates under different morphological units as an indicator of geological evolution, topographic variety, and land use. The revised Universal Soil Loss Equation model was employed to estimate the soil erosion rates and evaluate soil loss. The geographic information system was used to present the spatial distribution of soil erosion and its change induced by geological and morphological factors. Nonparametric multidimensional scaling ordinations were applied to evaluate similarities in soil erosion parameters between six geomorphological units. The analysis showed a clear clustering between morphological units, both in terms of absolute soil loss (stress value: 0.15, ANOSIM: R = 0.61, p = 0.001) and in the distribution pattern of erosion rates (stress value: 0.17, ANOSIM: R = 0.74, p = 0.001). Significant differences were observed in erosion rates, which range between 2.5 up to 65.9 t ha−1 yr−1, although 82% of the La Primavera present rates below 15 t ha−1 yr−1. The most eroded unit produces 351 thousand t yr−1, displaying a rate of 23.3 t ha−1 yr−1, while the least eroded unit produces 10 thousand t yr−1, displaying a rate of 2.5 t ha−1 yr−1. This study shows that integrating landscape evolution and morphology into soil erosion research enhances understanding of erosion processes, strengthening the LS Factor. Forest land use is often linked to preventing water erosion, but this study shows it depends on vegetation type; secondary vegetation can have higher erosion rates than conservation agriculture. Soil loss patterns show that each unit combines unique biophysical and human factors, requiring discrete units for systematic erosion analysis.

A comparative Study of the Erosive Wear Caused by Organic and Inorganic Abrasive Particles

In this study, erosion tests were conducted to evaluate the abrasivity of organic particles to produce wear on a material surface with higher hardness. The novelty of this research work was that pistachio shells, which are usually waste that ends up in the garbage, were collected, ground and sieved to obtain a sufficient quantity of pistachio angular particles to be used productively to perform these wear tests. Additionally, sea shells were thought of as an alternative to organic abrasives, and these were ground, sieved and prepared to be able to carry out the testing. The erosion tests conducted based on ASTM G76 and SEM images showed typical wear mechanisms such as high plastic deformation (material displacement) characterized by micro-cutting and micro-ploughing actions, grooves with lifted lips in the edges as pistachio grits employed to run the tests. On the other hand, a conventional abrasive as glass bead particles caused huge craters, broken and smeared flakes, ploughing and circumferential cracks on the AISI 420 stainless steel surfaces. The highest erosion rates were reached as glass beads were employed to run the erosion tests. AFM technique was used to show the surface variations after the erosive impacts. The eroded scars produced by pistachio and sea shells allowed us to remark that the proposed organic abrasives could be used for polishing, surface finishing and cleaning applications on surfaces of mechanical elements that are dirty or rusty. This was due to their low density, which led to low and very superficial erosion damage.

Slurry Jet Erosion Resistance of Stainless Steel 304 Reinforced with High Entropy Alloys through Friction Stir Processing

The present work adopts friction stir processing to process stainless steel (SS304) with cobalt-chromium-iron-copper-titanium and aluminium-silicon-beryllium-titanium-vanadium high entropy alloy and analyse its erosion performance. The processed samples with cobalt-chromium-iron-copper-titanium and aluminium-silicon-beryllium-titanium-vanadium display refined grain structure with uniform distribution of the reinforced high entropy alloys. The microhardness for the sample with cobalt-chromium-iron-copper-titanium is 22.1% better than the aluminium-silicon-beryllium-titanium-vanadium. The slurry jet erosion test conducted through different process parameters revealed 90° impingement angle and 10 m s−1 impact velocity with 10 wt% slurry concentration on the processed sample with cobalt-chromium-iron-copper-titanium offered better erosion resistance. Oblique angle endured high erosion rate due to the ploughing effect of abrasive erodent than normal angle deforming the surface. Increasing velocity increased the erosion rate by increased material removal. Slurry concentration forms a cloud-like layer at higher concentrations lowering the erosion rate. The subsequent microstructural evaluation showed the failure mode through the formation of platelets, micro-cuts, ploughing and plastic deformation.

Hydrological Modelling of Sediment Yield in the Upper Basin Region of Kirkuk City Watershed

Mountain sedimentation and undue erosion provide significant challenges for dams since materials accumulate within reservoirs that hold water, reducing the capacity for storing living water, which is the most important goal of dam building. Iraq is one of the nations that will have a big problem getting sufficient water because its water requirement continues to climb, and the supplying countries provide less water to Iraq. The present research focuses on the upper basin of the Kirkuk City watershed in northeastern Iraq. The largest watershed region, spanning approximately 420 km2 within Al-Sulaymaniyah and Kirkuk Provinces. The objective is to quantify and foresee the sediment yield in this basin using 43 years of daily environment information and various rainstorm events with various intensities. The model was adjusted and confirmed by comparing it to the monthly mean surface flow and sediment readings obtained at the Kirkuk gauging station. The Soil and Water Assessment Tool (SWAT) model was utilized to simulate the upper basin region of Kirkuk City. The aforementioned model uses the geographic information system (GIS) software to analyse necessary information from GIS layers of the electronic contour modelling kind of soil, using of land, and coverage by integrating it with the appropriate climatic information. The kinematic erosion (KINEROS) and runoff model can simulate intricate watershed behaviour by precisely adjusting for the geographical variation of soils, distribution of rainfall sequences, and vegetation. The hydrological features of the Kirkuk city basin reveal that the subdivisions with the highest erosion rates cannot transport the debris or deposits to the reservoir, primarily due to propagation damages, percolating, and other smaller barriers. The optimal curve number (CN) was determined to be between 84 and 88, while the land cover factor (C) ranged from 0.005 to 0.04. The model validation results indicate that the Kirkuk Dam reservoir received a total volume of water estimated at 118.7 million cubic metres (MCM) and a total silt yield of 0.85 million tonnes. The “KINEROS” simulation modelling for the sediment yield closely matches the upper basin of Kirkuk watershed's deformation and sedimentation behaviour during singular rainfall events; this is particularly true for parts of watersheds located near the watershed area entrance.

High temperature sand erosion failure mechanism of ceramic/metal multilayer coating

This paper investigates the high-temperature erosion mechanism of TiAlN/TiAl ceramic/metal multilayer coating within the temperature range of 200 °C to 500 °C. The phase and element analysis results indicate that c-TiAlN is stable under 200°C∼500°C. The elastic modulus and hardness of TiAlN/TiAl are 230 GPa and 26.7 GPa at 200 °C. When the temperature increases to 300 °C and higher, the elastic modulus and hardness rise to 295.7 GPa and 30.5 GPa. However, the hardness and elastic modulus of TiAl coating increase from 11 GPa and 120 GPa at 200°C to 24 GPa and 260 GPa at 500°C. High-temperature sand erosion test results reveal a trend in erosion rate for the TiAlN/TiAl multilayer coating, initially increasing and then decreasing with temperature elevation. The highest erosion rate, reaching 0.6×10-3 mm3·g-1, occurs at 300 °C. Failure analysis of sand erosion indicates longitudinal cracking propagation downwards at high temperatures, merging with transverse cracks, leading to a delamination failure mode layer by layer. However, with the temperature elevation from 300 °C to 400 °C, transverse cracks shift from the interfacial layer to the TiAl layer within the TiAlN/TiAl multilayer coating. Finite element analysis demonstrates that the hardness and elastic modulus of the TiAl layer increase, leading to increased stress on the TiAl layer of the TiAlN/TiAl multilayer coating, resulting in TiAl cracking.

Formation of an Active Giant Nonsulfide Zinc System, Jinding, China: Relationships Among Tectonics, Climate, and Supergene Metal Remobilization

Abstract The oxidized portion of the giant Jinding Zn-Pb deposit, Yunnan, China, accounts for about 40% of the original metal resource, indicating a nonsulfide zinc component of 80 to 90 million tonnes (Mt), making it among the largest nonsulfide zinc concentrations known. The presence of the Jinding deposit within a rugged topographic upland undergoing active weathering and erosion suggests that the nonsulfide zinc supergene system was active at the time of discovery. The ore-bearing strata cropped out at ~2800 m elevation, and strong oxidation effects are present to at least 200 m below the premining surface. The exhumation of the late Oligocene Jinding primary ores and exposure to groundwater modification may have been initiated by late Miocene uplift that coincides with the onset of the Southeast Asia monsoonal climate. The abundance of calcium carbonate in the Jinding host strata and primary ore results in the preserved nonsulfide zinc ores being dominated by smithsonite crusts of a variety of compositions, along with a diverse assemblage of supergene Zn-Pb and other minerals reflecting the primary ore composition. Complex microstratigraphic banding in smithsonite at scales of ≤20 µm is revealed by luminescent microscopy, likely recording groundwater-related annual precipitation events. Jinding smithsonites from the Beichang and Jaiyashan ore zones have δ18OV-SMOW values (in which V-SMOW = Vienna-standard mean ocean water) that vary between 18.6 and 21.5‰, which are unusually low compared with most supergene smithsonites. These values are consistent with the cold conditions of the Jinding area (11°C mean annual temperature) and are compatible with local cold springs and travertines. The δ13CV-PDB values (in which V-PDB = Vienna-Pee Dee Belemnite) of the Jinding smithsonites range between –10.1 and –3.6‰ and are distinct from calcites formed by local hot springs and from low-18O smithsonites from other nonsulfide zinc deposits. The light carbon isotope composition of Jinding smithsonites suggests a major contribution of organic carbon and only minor, if any, contributions from local Triassic marine limestone and atmospheric CO2. The 13C-depleted carbon likely was derived from soils with C3 plant-dominated organic matter, from oxidation of hydrocarbons in the primary ore, or from dissolution of isotopically light sandstone cements or ore calcites. Reaction path models show that the reaction of descending, cool, oxidizing, meteorically derived groundwater with calcite, CO2, and primary sulfide minerals can account for much of the observed supergene mineral assemblage. The Jinding nonsulfide zinc mineralization reflects the interrelationships among tectonic, climatic, and groundwater processes in high elevation and/or latitude settings, notably related to cold groundwater. Although the preservation of thick nonsulfide zinc concentrations was impeded by the dynamic regional tectonic and climatic conditions that resulted in high precipitation and erosion rates, the size of the primary ore zone and focused groundwater transport resulted in the development of a giant nonsulfide zinc mineralization system.

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.

Enhancing wind turbine blade protection: Solid particle erosion resistant ceramic oxides-reinforced epoxy coatings

In recent days, it is crucial for the globe to shift fossil fuel energies to renewable energies such as hydroelectric, wind, solar, tidal, geothermal, etc. to mitigate global warming issues. Wind energy has been regarded as one of the renewable energy sources to rely on in the future. In this aspect, wind turbine blade maintenance is quite a challenge in tropical areas like India. One of the main reasons why wind turbine blades get damaged and produce less energy is solid particle erosion. In the present work, epoxy nanocomposite coatings reinforced with Al2O3, ZrO2, and CeO2 nanoparticle fillers have been applied on glass fiber reinforced polymer (GFRP) substrates using a simple spray coating method. These nanoparticles have been prepared in-house by solution combustion synthesis (SCS) route using urea, glycine, and oxalyl dihydrazide fuels, respectively. X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy have been used to characterize the materials and coatings. Epoxy coatings with different Al2O3, ZrO2, and CeO2 nanoparticle concentrations have been subjected to solid particle erosion resistance tests at impinging angles of 30°, 60°, and 90°. ZrO2 and CeO2 nanoparticle-reinforced epoxy coatings show much better resistance to solid particle erosion than Al2O3-reinforced coatings. Estimated average erosion rates are 17 and 11.3 × 10−3 mm3 g−1, respectively, for epoxy coatings with 20 and 40 wt% ZrO2 nanoparticles. However, GFRP substrate and neat epoxy (EP) coating show much higher erosion rates with respect to nanoparticles-reinforced epoxy coatings. To ascertain a correlation between H3/E2 and the solid particle erosion rates of the coatings, nanoindentation tests have been carried out. Tensile strength and initial modulus of all the coatings are found to be directly proportional to the average erosion rates, whereas, elongation at break shows an inverse relationship with the average erosion rate. This correlation of mechanical properties with solid particle erosion performance can play a critical role in the development of realistic simulation of protective coatings for wind turbine blades.

Multi-hazard modeling of erosion and landslide susceptibility at the national scale in the example of North Macedonia

Abstract Due to favorable natural conditions and human impact, the territory of North Macedonia is very susceptible to natural hazards. Steep hillslopes combined with soft rocks (schists on the mountains; sands and sandstones in depressions), erodible soils, semiarid continental climate, and sparse vegetation cover give a high potential for soil erosion and landslides. For this reason, this study presents a multi-hazard approach to geohazard modeling on the national extent in the example of North Macedonia. Utilizing Geographic Information Systems, relevant data about the entire research area were employed to analyze and assess soil erosion and susceptibility to landslides and identify areas prone to both hazards. Using the Gavrilović Erosion Potential Method (EPM), an average value of 0.36 was obtained for the erosion coefficient Z, indicating low to moderate susceptibility to erosion. However, a significant area of the country (9.6%) is susceptible to high and excess erosion rates. For the landslide susceptibility assessment (LSA), the Analytical hierarchy process approach is combined with the statistical method (frequency ratio), showing that 29.3% of the territory belongs to the zone of high and very high landslide susceptibility. Then, the accuracy assessment is performed for both procedures (EPM and LSA), showing acceptable reliability. By overlapping both models, a multi-hazard map is prepared, indicating that 22.3% of North Macedonia territory is highly susceptible to erosion and landslides. The primary objective of multi-hazard modeling is to identify and delineate hazardous areas, thereby aiding in activities to reduce the hazards and mitigate future damage. This becomes particularly significant when considering the impact of climate change, which is associated with increased landslide and erosion susceptibility. The approach based on a national level presented in this work can provide valuable information for regional planning and decision-making processes.

Environmental Degradation Analysis of Former Bengawan Solo River Lake Ecosystem

The ecosystem of the former river section lake in the research area formed by the straightening of the river and located in the Sub-Urban area, faces significant environmental degradation such as pollution, erosion, and water shrinkage that threaten its sustainability. The magnitude of environmental degradation that occurs needs to be studied because it can result in a reduction in clean water and shallowing of the lake. Compared with lakes such as Poyang Lake in China, which has experienced a decline in water quantity and quality due to seasonal fluctuations, climate change and waste, this study offers a similar perspective by highlighting the interaction of natural and human factors, and adds a new dimension related to degradation caused by erosion. This study uses a comprehensive approach, namely by combining image analysis, field measurements using measuring sticks, USV, geodetic GPS, laboratory analysis, and interviews. The results of the study indicate that the lake water quality status ranges from "moderately polluted" to "heavily polluted," while the groundwater quality varies from "meets quality standards" to "lightly polluted." The high water quality status is caused by human activities and land conditions, as well as the high rate of erosion around the lake reaching 289.63 tons/ha/year, with an average soil loss of 0.11 tons/year. In addition, the lake in the study area has shrunk by up to 72% due to seasonal fluctuations and climate change. Based on this, effective management is needed to maintain the ecological balance and environmental health of the former river section lake.

Quantitative Evaluation of Soil Erosion in Loess Hilly Area of Western Henan Based on Sampling Approach

The terrain in the loess hilly area of western Henan is fragmented, with steep slopes and weak soil erosion resistance. The substantial soil erosion in this region results in plenty of problems, including decreased soil productivity and ecological degradation. These problems significantly hinder the social and economic development in the region. Soil conservation planning and ecological development require accurate soil erosion surveys. However, the studies of spatio-temporal patterns, evolution, and the driving force of soil erosion in this region are insufficient. Therefore, based on a multi-stage, unequal probability, systematic area sampling method and field investigation, the soil erosion of the loess hilly area of western Henan was quantitatively evaluated by the Chinese Soil Loss Equation (CSLE) in 2022. The impact forces of soil erosion were analyzed by means of a geographic detector and multiple linear regression analysis, and the key driving factors of the spatio-temporal evolution of soil erosion in this region were revealed. The results were as follows. (1) The average soil erosion rate of the loess hilly area in western Henan in 2022 was 5.94 t⋅ha−1⋅a−1, with a percentage of soil erosion area of 29.10%. (2) High soil erosion rates mainly appeared in the west of Shangjie, Xingyang, and Jiyuan, which are related to the development of production and construction projects in these areas. The areas with a high percentage of soil erosion area were in the north (Xinan and Yima), west (Lushi), and southeast (Songxian and Ruyang) of the study area. Moreover, areas with the most erosion were found in forest land, cultivated land, and areas with a slope above 25°. (3) At the landscape level, the number and density of patches of all land types, except orchard land, increased significantly, and the boundary perimeter, landscape pattern segmentation, and degree of fragmentation increased. (4) The geographical detector and multiple linear regression analysis indicated that the driving forces of soil erosion are mainly topographic and climatic (slope length, elevation, precipitation, and temperature). Soil erosion was significantly influenced by the density of landscape patches. These maps and factors influencing soil erosion can serve as valuable sources of information for regional soil conservation plans and ecological environment improvements.

Towards accurate modelling of rock surface exposure dating using luminescence to estimate post-exposure erosion rate

Depth-dependent luminescence in the top few millimetres of rock surface emerges as a potential tool to estimate rock surface exposure age and post-exposure erosion rate. It relies on the principle that the luminescence depth profile (LDP) propagates deeper with the time of sunlight exposure and moves to shallower depth with the erosion rate. The propagation of LDP is generally assumed to follow the first-order kinetic (FOK) model, except for a few recent studies. The FOK model predicts an exponential decay of infrared stimulated luminescence (IRSL) signal with light exposure time, which rarely corroborates experimental observation; IRSL signal decay is much slower than exponential decay. The faster decay of IRSL, predicted by the FOK model, results in faster propagation of LDP and thus always underestimates the exposure age and translates into a higher erosion rate. Interestingly, the slower-than-exponential decay of the IRSL signal can be better explained by general order kinetics (GOK). Thus, recent studies on rock surface luminescence dating have employed the GOK model. However, the GOK model is yet to be explored to predict post-exposure erosion rates. Here, we apply the GOK model and theoretically demonstrate the impact of the order of kinetics on the calibration and propagation of LDP in the presence of erosion and how the LDP's transient to steady state transition depends on the order of kinetics. We have performed a series of synthetic tests to assess the impact of selecting an incorrect model on the prediction of erosion rate. Finally, using the revised rate equation, the erosion rates are recalculated for natural samples (data available in the literature: Lehmann et al. (2019b)) and the impact of GOK on the predicted erosion rate is discussed.

Thermal and statistical analysis of the high-Z tungsten-based UFOs observed during the first deuterium high fluence campaign of the WEST tokamak

This paper summarizes the observations on the Unidentified Flying Object (UFO) observed during the first high fluence campaign performed in WEST. The campaign was characterized by high erosion and deposition rates, generating dusts and deposits prone to flaking during plasma operation. A total of 686 UFOs have been detected for 384 discharges executed, in which 133 UFOs lead to a disruption. These UFOs appear mostly during the low hybrid heating ramp-up early in the discharges. The mechanisms leading to a disruption is described as well as the delay available to react after the UFO entering in the plasma. The UFOs originate mostly from the high field side corresponding to the thick deposit area. These UFOs can be debris from a preceding disruption (≈27 %) or come from progressive loss of adherence of the thick deposits (≈55 %) under plasma cycling or more likely by disruption on this area. Finally, the thermal resistance of the poorly attached deposits has been calculated in the range from 2.10−4 °C m2/W to 1.10−3 °C m2/W coherent with previous observations in the high field side of the JET divertor.

Probabilistic hazard analyses for a small island: methods for quantifying tephra fall hazard and appraising possible impacts on Ascension Island

Proximal to the source, tephra fall can cause severe disruption, and populations of small volcanically active islands can be particularly susceptible. Volcanic hazard assessments draw on data from past events generated from historical observations and the geological record. However, on small volcanic islands, many eruptive deposits are under-represented or missing due to the bulk of tephra being deposited offshore and high erosion rates from weather and landslides. Ascension Island is such an island located in the South Atlantic, with geological evidence of mafic and felsic explosive volcanism. Limited tephra preservation makes it difficult to correlate explosive eruption deposits and constrains the frequency or magnitude of past eruptions. We therefore combined knowledge from the geological record together with eruptions from the analogous São Miguel island, Azores, to probabilistically model a range of possible future explosive eruption scenarios. We simulated felsic events from a single vent in the east of the island, and, as mafic volcanism has largely occurred from monogenetic vents, we accounted for uncertainty in future vent location by using a grid of equally probable source locations within the areas of most recent eruptive activity. We investigated the hazards and some potential impacts of short-lived explosive events where tephra fall deposits could cause significant damage and our results provide probabilities of tephra fall loads from modelled events exceeding threshold values for potential damage. For basaltic events with 6–10 km plume heights, we found a 50% probability that tephra fallout across the west side of the island would impact roads and the airport during a single explosive event, and if roofs cannot be cleared, three modelled explosive phases produced tephra loads that may be sufficient to cause roof collapse (≥ 100 kg m−2). For trachytic events, our results show a 50% probability of loads of 2–12 kg m−2 for a plume height of 6 km increasing to 898–3167 kg m−2 for a plume height of 19 km. Our results can assist in raising awareness of the potential impacts of tephra fall from short-lived explosive events on small islands.

Mapping of Soil Erosion Vulnerability in Wadi Bin Abdullah, Saudi Arabia through RUSLE and Remote Sensing

This study investigates soil loss in the Wadi Bin Abdullah watershed using the Revised Universal Soil Loss Equation (RUSLE) combined with advanced tools, such as remote sensing and the Geographic Information System (GIS). By leveraging the ALOS PALSAR Digital Elevation Model (DEM), Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) rainfall data, and the Digital Soil Map of the World (DSMW), the research accurately evaluates soil loss loads. The methodology identifies significant variations in soil loss rates across the entire watershed, with values ranging from 1 to 1189 tons per hectare per year. The classification of soil loss into four stages—very low (0–15 t/ha/yr), low (15–45 t/ha/yr), moderate (45–75 t/ha/yr), and high (>75 t/ha/yr)—provides a nuanced perspective on soil loss dynamics. Notably, 20% of the basin exhibited a soil loss rate of 36 tons per hectare per year. These high rates of soil erosion are attributed to certain factors, such as steep slopes, sparse vegetation cover, and intense rainfall events. These results align with regional and global studies and highlight the impact of topography, land use, and soil properties on soil loss. Moreover, the research emphasizes the importance of integrating empirical soil loss models with modern technological approaches to identify soil loss-prone locations and precisely quantify soil loss rates. These findings provide valuable insights for developing environmental management strategies aimed at mitigating the impacts of soil loss, promoting sustainable land use practices, and supporting resource conservation efforts in arid and semi-arid regions.

Assessing the sustainability of small hydropower sites in the Citarum Watershed, Indonesia employing CA-Markov and SWAT models

ABSTRACT This study investigates the sustainability of potential small hydropower sites within the Citarum Watershed in West Java, Indonesia. The Citarum River, with a catchment area of 6,090 km2, plays a crucial role in regional water supply and hydroelectric power generation. However, environmental challenges such as deforestation, land use changes, and sedimentation pose significant risks. We employed the CA-Markov model integrated with IDRISI TerrSet software and the Soil and Water Assessment Tool to predict future land use changes and assess water supply, soil erosion, and sedimentation impacts for 2030 and 2040. The analysis revealed diverse trends in water yield across different catchment areas, with some regions showing increased water availability and others facing declines. High erosion and sedimentation rates were identified as critical issues affecting hydropower efficiency. The study highlights the need for comprehensive watershed management strategies, including reforestation, sustainable land management practices, and sediment management, to enhance the sustainability of small hydropower projects. Our findings underscore the importance of integrating environmental considerations into hydropower development to ensure the ecological integrity of the Citarum Watershed.

Using USLE, GIS and remote sensing for the soil loss assessment in the National Park of Theniet El Had, Algeria

Soil water erosion is one of the problems that affect the environment, agriculture and social life by threatening several land surfaces. The objective of this study is to use the USLE model, GIS and remote sensing (RS) to estimate the annual rate of soil loss by water erosion in the Theniet El Had National Park (THNP) which belongs to the mountainous ecosystem of Djebel El Meddad, located in the northwest of Algeria. The use of the USLE model takes into account the five factors controlling water erosion, namely: the rain erosivity (R) determined from the annual rainfall data, the soil erodibility (K) developed from soil survey data, the slope lengths (LS) generated by using DEM, the vegetation cover (C) by the use of RS data and erosion control management practices (P) by field trips. The integration of these factors made it possible to establish the quantitative map of the annual rate of soil loss varying between 0.02 and 55.10 (t/ha.year), with an average of around 6.64 (t/ha.year). Five erosion aggressiveness classes are used; very weak, weak, moderate, strong and very strong which represent a rate respectively of 23.70, 44.65, 22.72, 4.41 and 4.52 % of the study area surface. The areas with high and very high erosion rates are located in the north having a very rugged relief and low vegetation cover. This study can be used in the mountainous ecosystems and it will make it possible to set up priority intervention zones to combat the risk of water erosion.