Flood events are major drivers of soil erosion and sediment yield on the Loess Plateau, where extensive ecological restoration has been implemented. This study investigates runoff–sediment dynamics by analyzing 215 flood events recorded in the Chabagou watershed (1959–2022), with a focus on changes under intensifying restoration efforts. Using long-term hydrological and rainfall data, we applied cluster and discriminant analyses to classify flood events based on sediment hysteresis loops and evaluated variations across three management periods (1959–1979, 1980–1999, and 2000–2022), characterized by progressive increases in check dam construction and vegetation recovery. The results show that the floods characterized by short duration, low peak flow, and low sediment concentration were predominant, accounting for 77.7% of the recorded 215 events. A clear decreasing trend was observed, with average sediment yield and peak discharge declining by approximately 68% and 52%, respectively. Anticlockwise hysteresis loops were most common (45.6%), followed by complex (27.9%) and figure-of-eight loops (23.7%). The proportion of figure-of-eight loops increased notably from 17% to 39%, indicating reduced sediment connectivity due to large-scale ecological restoration. Extreme rainfall events consistently produced complex hysteresis patterns, influenced mainly by rainfall intensity but increasingly modulated by human interventions. These results highlight adaptive watershed management strategies that target figure-of-eight and complex flood events to mitigate erosion and flood risks.

Sediment yield in mountain regions in the context of climate change: A systematic review

Sediment yield assessment of a small ungauged montane catchment in the North Caucasus

Soil erosion represents a significant yet often underrecognised threat to water management in southern Africa, particularly within water source areas located in mountainous regions such as the Limpopo River Basin (LRB). Since previous soil erosion maps of the LRB are global assessments coupled with spatial uncertainties, a need to improve techniques of mapping the soil erosion risk in the LRB was identified by the Limpopo Watercourse Commission (LIMCOM). The aim of this study is to create an improved soil erosion risk map and model the sediment yield potential of the LRB. This was achieved by interfacing the Revised Universal Soil Loss Equation (RUSLE) in a GIS, as well as the application of a sediment delivery ratio (SDR) model and the index of connectivity method to estimate the potential sediment yield. Multiple geo-spatial datasets were formatted at a regional and transboundary scale to improve the most important water erosion risk factors, namely rainfall erosivity, soil erodibility, topography, vegetation cover and support practices. According to the results, the average soil erosion rate of the LRB is 7.0 t/ha·yr−1, and the area of land with a moderate to extremely high erosion risk (>12 t/ha·yr−1) totals nearly 6 million ha (14% of the basin land surface). Results indicate that a combination of erodible soils and poor vegetation cover leads to the occurrence of erosion on flat, low-lying areas (mountain footslopes and valley floors) instead of steep mountainous terrain (midslopes and crests) as frequently determined in other parts of the world.

Fertilization plays an important role in soil nutrient loss from sloping croplands. However, the effect of fertilization on Molybdenum (Mo) loss remains unknown. The aims of this study were to explore the effects of different fertilizers of purple soil on the characteristics of soil molybdenum loss in surface, subsurface runoff and sediments. Five fertilizers treatments (3 replicates) were designed as following: no fertilizer (CK); conventional nitrogen, phosphorus, and potassium fertilizer (NPK); organic fertilizers with livestock manure (OM); nitrogen, phosphorus, and potassium fertilizer plus organic fertilizers with livestock manure (OMNPK); and straw turnover plus nitrogen, phosphorus, and potassium fertilizer (RSDNPK). The changes of runoff-related Molybdenum loss from June to September 2025 were studied. Results showed that fertilization significantly reduced surface runoff and sediment yield compared with CK (p < 0.05). The RSDNPK treatment exhibited the lowest surface runoff, while OM and OMNPK treatments most effectively decreased sediment loss. Dissolved Mo (DMo) was the predominant form of Mo loss across all treatments (50~70% of total loss), significantly higher than particulate Mo (PMo, 25~40%) and Mo of soil sediments (SEMo, 6.5~12.9%). Notably, the OM treatment uniquely shifted Mo loss toward subsurface flow (47.2% of total), whereas other treatments were dominated by surface runoff. Total Mo loss amount varied significantly among treatments (p < 0.05): CK (795 μg/m2) > OM (685 μg/m2) > NPK (596 μg/m2) > OMNPK (533 μg/m2) > RSDNPK (373 μg/m2). The RSDNPK treatment achieved the optimal performance, reducing total Mo loss by 53.1% compared with CK. Structural equation modeling revealed that soil organic matter indirectly controlled Mo loss by modifying soil physical properties and hydrological processes. The findings demonstrate that RSDNPK represents the most effective strategy for minimizing Mo loss in purple soil sloping croplands, outperforming sole organic manure application. This study highlights the importance of organic amendment and management in Mo loss control and provides a scientific basis for sustainable nutrient management in erosion-prone agricultural systems.

ABSTRACT The interactive effects of gravel content and slope gradient on soil erosion processes of sloping farmland remain inadequately quantified, limiting predictive capabilities and effective conservation. This study investigated how gravel content, rainfall intensity, and slope gradient collectively influenced the particle size distribution of eroded sediment, thereby advancing the mechanistic understanding of soil erosion processes on sloping farmland containing gravel. Through simulated rainfall experiments, the results demonstrated that sediment yield was more sensitive to rainfall intensity than to other factors, and slopes containing gravel generally yielded more sediment than those without gravel. Fine sand, which accounted for 49%–56%, was the dominant fraction, with a clear coarsening trend observed under higher rainfall intensities. Critically, gravel presence significantly altered sediment structure, reducing the mean weight diameter (MWD) while increasing the fractal dimension ( D ). A key finding was the significant interactive effect ( p < 0.05) between gravel content and slope gradient on particle sorting. The treatment with 20% gravel content and a 15° slope gradient was identified as optimal, promoting the enrichment of clay and silt and suggesting improved aggregate stability and permeability. The findings reveal the complex role of gravel in erosion processes, highlighting its potential to exacerbate sediment yield under certain conditions. The results of this study provide theoretical and data‐based support for the management and conservation of sloping farmland containing gravel in the Three Gorges Reservoir area.

Abstract Purpose Eutrophication and nuisance filamentous algal blooms (i.e. Cladophora ) are increasingly common occurrences throughout much of the western United States. Wildfire may be contributing to the frequency and magnitude of algal blooms through excess sediment and nutrient loading to streams and rivers. Our objective was to evaluate the effects the 2021 Woods Creek Fire had on sediment yields and phosphorus (total and bioavailable) partitioning in Camas Creek, a major tributary to the Smith River in Montana where Cladophora are now consistently reaching nuisance levels. Methods We collected water quality samples during snowmelt pulsing events as well as fixed interval sampling using an established U.S. Geological Survey stream gage instrumented with a continuous water quality sonde and an automatic peristaltic pump sampler. Water samples were processed for total phosphorus (TP), sediment-bound bioavailable phosphorus (S-BioP), soluble reactive phosphorus (SRP), and suspended sediment concentrations and were evaluated using linear regression and other nonparametric statistical tests. Continuous turbidity and streamflow were evaluated using hysteresis analysis to determine sediment sourcing and connectivity. Results We found that the Woods Creek Fire did not significantly influence TP and S-BioP in Camas Creek. However, there was a significant increase in SRP and turbidity in both postfire years (2022 and 2023). Hysteresis analysis of 91 delineated events indicated positive (clockwise) hysteresis was the dominant event pattern during the snowmelt period. This may indicate a lower hillslope to channel connectivity, with the major sediment supply originating from the channel and/or riparian areas. Conclusion Results from this study demonstrate the benefits of combining discrete water quality samples with high-frequency turbidity sensors to characterize postfire sediment and phosphorus dynamics. While a lack of postfire response in TP and S-BioP is contrary to many other studies, our findings highlight the role climate and catchment morphology play in attenuating a disturbance effect.

ABSTRACT Under the combined influence of climate change and human activities, analysing and predicting water and sediment dynamics is essential for watershed management. This study investigates the Tao River Basin (TRB) on the Tibetan Plateau and the Zuli River Basin (ZRB) on the Loess Plateau—both major tributaries of the upper Yellow River with distinct eco‐geographical features. Using the SWAT model to simulate runoff and sediment processes, and partial least squares structural equation modelling (PLS‐SEM) to quantify driving mechanisms, we compared how these basins respond to future climate and land use changes. SWAT parameter comparisons revealed that TRB processes are more influenced by vegetation cover and baseflow, whereas ZRB processes are more sensitive to soil properties, moisture transport and channel erosion. PLS‐SEM results showed that in the TRB, runoff is mainly driven by precipitation (positive effect) and temperature (suppressive effect), with the positive role of NDVI increasing over time. Sediment dynamics are predominantly controlled by precipitation, with its indirect effects (via NDVI and runoff) outweighing direct meteorological impacts. In the ZRB, runoff is the primary driver of sediment, while precipitation influences both runoff and sediment mainly through vegetation. Temperature has little effect on sediment, and vegetation consistently reduces sediment yield. Scenario analyses indicated distinct trends. Under the low‐emission scenario combined with ecological‐economic land use, both runoff and sediment are projected to decrease. In contrast, under medium‐ and high‐emission scenarios, both are projected to increase. Notably, the TRB, with its superior vegetation cover, exhibited significantly smaller fluctuations in runoff and sediment across all scenarios. This highlights the key buffering role of vegetation against climate impacts. Therefore, forest and grassland restoration can mitigate climate effects on water and sediment processes. However, sediment control measures may also reduce river runoff, underscoring the need to sustain runoff resources while balancing ecological and socio‐economic water needs.

Integrated RUSLE–GIS–RS analysis of soil erosion and sediment yield in the Wadi cheliff Basin, Algeria

Estimating soil erosion and sediment yield using geographic information systems in southeastern Morocco: The case of the high and middle Drâa watershed

Watersheds provide fundamental hydrological ecosystem services for human well-being and the environment, such as water provisioning, hydrological cycle regulation, and erosion control; however, these services face increasing anthropogenic and climatic pressures. This study assessed individual and combined impacts on the hydrological functionality of the Piuray–Ccorimarca watershed (Cusco, Peru) using a calibrated Soil and Water Assessment Tool (SWAT) model, analyzing water yield, soil water storage, and sediment transport across 20 scenarios. An ensemble of 10 Coupled Model Intercomparison Project Phase 6 (CMIP6) models with bias correction was implemented, integrated with land transformation projections contemplating urban expansion associated with airport development and forest recovery through Payment for Ecosystem Services mechanisms. The results reveal climate change as the dominant driver, generating water yield increases and soil water content improvements primarily due to evapotranspiration decoupling that increases the runoff coefficient. In contrast, land use change produces substantially smaller hydrological effects but critically intensifies sediment yield. Spatial vulnerability analysis identified eight persistently critical sub-basins (20.5% of area) where soil water content emerged as the dominant limiting factor. These findings establish a clear management hierarchy prioritizing climate adaptation over land use interventions, with differentiated strategies required for critical zones demanding structural interventions versus non-critical areas amenable to flexible conservation approaches.

Tectonic activity and seismicity impacts on the sediment yield of Iranian basins

Abstract Soil erosion is a significant environmental concern in Ethiopia, particularly in agricultural landscapes. This study assesses soil erosion risk and sediment yield using GIS-based Revised Universal Soil Loss Equation (RUSLE) modeling in the Hamassa Watershed, Southern Ethiopia. The region receives an average annual rainfall of approximately 1,293.5 mm, with rainfall erosivity (R-factor) values ranging from 668.98 to 763.15 MJ mm ha −1 h −1 yr −1 . Soil erodibility (K-factor) varies between 0.13 and 0.30 t ha h ha −1 MJ −1 mm −1 , with Chromic Vertisols covering 76.3% of the watershed. The slope length and steepness (LS-factor) range from 0.072 to 148.37, highlighting high erosion risks in steeper areas. Land cover and management (C-factor) values range from 0.023 to 0.05. The model estimates an average annual soil loss of 14.75 t ha −1 yr −1 , with severity levels classified as very slight (47.8%), slight (29.4%), moderate (11.3%), severe (5.5%), and very severe (6.0%). The sediment delivery ratio (SDR) is calculated at 0.28, resulting in a sediment yield of 3.25 t ha −1 yr −1 . Five sub-watersheds (SWS3, SWS6, SWS8, SWS10, and SWS1) were identified as erosion hotspot areas, accounting for 73.8% of the total erosion in the watershed. These findings provide valuable insights for prioritizing conservation efforts and managing soil and water resources in the Hamassa Watershed, offering actionable recommendations for sustainable land management practices. Furthermore, this finding is crucial for advancing key sustainable development goals (SDGs) by supporting efforts to ensure clean water and sanitation, life on land, and climate action.

Abstract This study investigates the interactions between sediments and biota in the Mariuá Archipelago, a mega‐complex anabranching reach of the Negro River, the main blackwater river in the Amazon Basin, to understand the dynamics of the ecosystem in cratonic systems with limited supply. Using satellite imagery and hydrological data (2019–2024), we characterized suspended sediment concentration (SSC) patterns and evaluated geomorphological controls on habitat stability. Results revealed minimal inter‐channel SSC variation (6.53–7.32 mg.L −1 ) across the archipelago, contrasting sharply with sediment‐rich Andean tributaries. Annual suspended sediment flux decreased 23% through the archipelago (4.48 × 10 6 ton.year −1 upstream to 3.38 × 10 6 ton.year −1 downstream), indicating net retention of 1.10 × 10 6 ton.year −1 within inter‐island lakes and floodplains. The low specific sediment yield (12–15 ton.km −2 .year −1 ) and the contemporary sedimentation rate (0.10 ± 0.05 mm.year −1 ) contrast with Middle Holocene formation conditions, when the Negro River had higher energy and a greater sediment concentration than at present. Low correlations between SSC, water discharge and precipitation (r ≤ 0.51) demonstrate limited environmental forcing in this cratonic landscape. Spatial analysis reveals that downstream lakes function as suspended sediment sinks, concentrating fine particles during low‐water periods and supporting distinct aquatic plant communities. This supply‐limited regime enables ecosystem stability through reduced sediment‐mediated disturbance, maintaining persistent habitats for endemic biota since the Pleistocene. However, mining, deforestation and climate change threaten this equilibrium by potentially increasing suspended sediment inputs beyond historical ranges. Geomorphological constraints in ancient cratonic systems promote long‐term ecological stability, rather than disturbance‐driven dynamics. This study provides new insights for the conservation planning of fluvial ecosystems in this unique landscape.

Sediment yield prediction in ridge-furrow rainwater harvesting using coupled USLE–SCS-CN model on the Loess Plateau, China

The Lalmai Hills in Cumilla are a low-relief hill range with high cultural and ecological value but increasing exposure to land-cover conversion, slope modification, and intense monsoon rainfall. This manuscript provides a secondary-data assessment of environmental change and soil erosion risk over 2005-2025, integrating published studies, open satellite observations, reanalysis rainfall products, and widely used erosion-risk modeling concepts (USLE/RUSLE). We synthesize evidence of declining tree cover, growing built-up footprints, and recurrent hill-cutting pressures, and we map how these changes interact with local topography and rainfall erosivity to elevate erosion risk along disturbed slopes and drainage lines. A conceptual framework and risk pathway matrix are provided to connect drivers, pressures, hazard generation, and downstream impacts on soils, waterways, infrastructure, and livelihoods. Although this is not a full GIS model, the combined evidence indicates a shift toward higher-frequency exposure of bare/compacted surfaces during erosive rainfall, implying increasing sediment yields and localized gully initiation. The paper concludes with a practical monitoring and mitigation agenda focused on slope stabilization, revegetation, runoff control, and enforcement against illegal hill cutting.

The Mun River Basin, the largest Mekong tributary in Northeast Thailand, has experienced extensive agricultural expansion and forest decline, raising concerns over increasing soil erosion and sediment transfer. This study provides an integrated assessment of soil loss, sediment yield (SY), and sediment delivery ratio (SDR) across 19 sub-watersheds using the Universal Soil Loss Equation (USLE), field-based SY data, and multivariate statistical analyses in 2024. Basinwide soil loss was estimated at ~35 million t y−1 (mean 4.96 t ha−1 y−1), with more than 80% of the basin classified in the no erosion to very low erosion classes. Despite substantial hillslope erosion, only 402,405 t y−1 of sediment reaches the river network, corresponding to a low SDR of 1.15%, which falls within the range reported for large tropical watersheds with significant reservoir infrastructure. Soil loss is most strongly influenced by slope and forested terrain, while SY responds primarily to rainfall and tree plantations; urban land, croplands, and reservoirs act as sediment sinks. Principal Component Analysis (PCA) resolved multicollinearity and produced six components explaining over 90% of predictor variance. A PCA-based regression model predicted SY per unit area with high accuracy (r = 0.81). The results highlight the dominant roles of hydroclimate and land-use structure in shaping sediment connectivity, supporting targeted soil and watershed-management strategies.

The ecological problem of formation and accumulation of waste oils is considered. It has been shown that extraction processes are a promising direction for the regeneration of used oils, in particular, the direction of "green chemistry" – extraction without an organic solvent in the presence of a surfactant. The possibility of using the water – neonol AF 9-6 – sodium sulfate system for waste oil purification has been studied. The dependence of the change in the output of the formed sludge during the purification of waste oil on the temperature of the process is shown. The behavior of the system in the area of micelle densification at temperatures of 40, 55, and 60 °C. has been studied. It has been established that the optimal temperature for cleaning waste oil is 55 °C, regardless of the concentration of the reagents used. The effect of the ratio of the components of the water – neonol AF 9-6 – sodium sulfate system on the process of waste oil purification at an optimal process temperature has been studied. It is shown that the optimal composition of the water – neonol AF 9-6 – sodium sulfate system for waste oil purification contains 80 wt.% water, 15 wt.% neonol and 5 wt.% of sodium sulfate, which is confirmed by the highest sediment yield (44% by weight). The effect of the ratio of the components of the water – neonol AF 9-6 – sodium sulfate system on the number of polluting particles in purified oils has been studied. It was found that the greatest reduction in the number of polluting particles (5.5 times compared with the spent oil before cleaning) is observed in the case of using a system containing 80% by weight of water, 15% by weight.% neonol AF 9-6 and 5 wt.% sodium sulfate. For citation: Zholnerkevich V.I., Shrubok A.O. Application of the water – neonol AF 9-6 – sodium sulfate system for cleaning used semi-synthetic engine oil. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 3. P. 57-63. DOI: 10.6060/ivkkt.20266903.6664.

Partitioning the relative contributions of slope and gully erosion in small agricultural watersheds on the Loess Plateau

Abstract Sediment yield prediction is vital for sustainable watershed management, particularly in data-scarce regions. This study, conducted in the Göksun Çayı Karaahmet sub-basin, Türkiye, evaluated whether sediment connectivity indices can reproduce outputs from the Revised Universal Soil Loss Equation (RUSLE) and Modified Universal Soil Loss Equation (MUSLE). Sediment yield was modeled for 196 sub-catchments and 69 rainfall events over 10 years using GIS-based factors: rainfall erosivity, soil erodibility, slope length-steepness, land cover, and hydrological parameters. Despite different assumptions (rainfall erosivity versus runoff and peak discharge), RUSLE and MUSLE showed strong agreement (R² = 0.87 at the event scale; R² = 0.93 at the sub-catchment scale). Predicted sediment yields ranged from 0.02 to 16.46 t ha -1 (MUSLE) and 0.04–10.63 t ha -1 (RUSLE/SDR), with mean values of 0.89 and 0.96 t ha -1 , respectively. Sediment connectivity indices-including the Index of Connectivity (IC), Sediment Delivery Ratio (SDR), and Topographic Wetness Index (TWI), were applied as inputs to five machine learning (ML) models (XGBoost, Random Forest, k-NN, SVR, and ANN). XGBoost and Random Forest achieved the best performance (R² = 0.912–0.942, RMSE = 0.065–0.089, MAE = 0.047–0.055), reproducing empirical outputs. IC, SDR, and TWI were dominant predictors. These results demonstrate that connectivity metrics integrated with ML can emulate empirical erosion models, offering a scalable, data-efficient alternative for ungauged basins. However, because the models were trained on RUSLE/MUSLE outputs from 69 events under static land use and climate, they may underpredict extreme sediment events and require field validation before operational use.