Search Results (548)

Yellow River irrigation districts must maintain food production under variable inflows, rigid diversion quotas, sedimentation, groundwater depletion, and soil salinization. This systematic review synthesized 79 journal articles from Web of Science and CNKI to clarify how resilience can be assessed and managed at the irrigation-district scale. The evidence indicates that resilience is a time-dependent combination of resistance, recovery, adaptability, and transformability within a coupled water source–canal–field–drainage–ecology–institution system. Although composite indices and hydrological–crop models have advanced, three gaps remain: operational thresholds rarely connect indicators to failure and recovery; farmer and institutional feedbacks are weakly represented; and assessments seldom translate into executable schedules. We, therefore, propose an irrigation-district-specific framework that couples water, sediment, salt, crops, ecology, and governance across basin–district–field scales without transferring risk between scales. Management priorities differ spatially: upstream districts require coordinated water–salt control; middle-reach well–canal systems require surface-water substitution and groundwater recovery; and downstream diversion districts require multi-source allocation and adaptive intake. A digital twin-based closed loop—continuous monitoring, forecasting, optimization, operational commands, and feedback correction—can translate diagnosis into canal rotation, recharge, drainage, and emergency actions. This review provides operational indicators and a decision-oriented research agenda for resilient irrigation modernization. Full article

The wind–water erosion crisscross region in the middle reaches of the Yellow River is a typical ecologically fragile area in China, which seriously restricts the sustainable development of the regional ecological environment. For the soil wind erosion issue in typical wind–water compound erosion zones, this study selected three representative watersheds from different sub-regions, namely Liudaogou, Zhifanggou, and Hailesitaigou, as the research objects. Indoor wind tunnel experiments were conducted to investigate the driving mechanisms of wind speed, soil moisture content, and vegetation coverage on wind erosion processes under different underlying surface conditions, and to compare near-surface soil wind erosion responses among three typical watersheds with different soil backgrounds. The results indicated that when soil moisture content increased from 0.01 to 0.05 g/g, the threshold wind velocities for sand entrainment in Liudaogou, Zhifanggou and Hailesitaigou increased by 5%, 10%, and 5%, respectively. Regression analysis was adopted to establish the empirical formulas of critical sand-blowing wind speed for each watershed, and soil moisture content exerted the most significant influence on the critical wind speed in the Zhifanggou watershed. At a constant wind speed, the increases in soil moisture content and vegetation coverage could markedly reduce wind erosion yield. Under the wind speed of 12–18 m/s, wind erosion yield was strongly dominated by wind speed and weakly affected by soil moisture content. The improvement of vegetation coverage could substantially mitigate wind erosion intensity. Additionally, soil moisture content and vegetation coverage presented more prominent inhibitory effects on near-surface sediment transport. The three watersheds exhibited different wind erosion response patterns and sensitivity characteristics, indicating that soil type and underlying surface conditions should be fully considered when conducting wind erosion risk assessment and vegetation restoration planning in the wind–water erosion crisscross region. Full article

Heavy-metal contamination in alpine agricultural watersheds reflects interacting geological, environmental, and anthropogenic controls. In this study, arsenic (As), copper (Cu), lead (Pb), zinc (Zn), and chromium (Cr) were investigated in 213 farmland soil and sediment samples collected from the Nyangqu River Basin during 2019–2021 and 2024–2025. Pollution status and ecological risks were evaluated using the Nemerow Integrated Pollution Index (Pn) and Håkanson Potential Ecological Risk Index (RI), while potential factors associated with spatial variation were explored using GeoDetector and an explainable machine-learning framework integrating XGBoost, SHAP, and LIME. Mean As, Cu, Zn, and Cr concentrations exceeded Tibetan soil background values, whereas mean Pb remained below background. Farmland soils exhibited higher concentrations of As, Pb, and Zn than sediments, whereas Cu displayed comparable levels between the two media. Among the investigated metals, As showed persistent enrichment, whereas Cr exhibited the greatest spatial variability and strongest local anomalies. Overall, slight pollution dominated the study area (69.0%; median Pn = 1.73), although several hotspots increased the mean Pn to 2.10, indicating moderate pollution at the regional scale. After applying coefficient-adjusted thresholds (23/133), the ecological risk index (RI) ranged from 16.45 to 54.24 (mean = 32.70), with 5.6%, 93.9%, and 0.5% of samples categorized as low, moderate, and considerable risk, respectively, and no samples exhibiting high risk. The associated environmental factors showed element-specific patterns, involving soil physicochemical conditions, geological background, and localized anthropogenic indicators. Notably, factor combinations generally showed greater explanatory power than individual covariates, suggesting stronger joint statistical associations with heavy-metal spatial differentiation. Full article

The surface soil in the Shendong mining area is dominated by aeolian sand and sandy sediment, while precipitation is limited, and evaporation is intense. Under these conditions, shallow reconstructed soil has difficulty retaining plant-available water, which constrains vegetation restoration. This study evaluated how low-range increases in fine-particle clay content affect both water retention and upward water conduction in sandy reconstructed soil. Sandy material from the Shangwan mining area and exogenous river clay were mixed into four treatments, and soil water characteristic curves (SWCCs) were determined by centrifuge over 10–1000 kPa matric suction. The data were fitted with the Van Genuchten model and combined with capillary-rise tests. The results showed that increasing fine-particle content shifted the SWCC upward and raised both saturated and residual volumetric water contents. SN10 reached 17.18% and 5.55% volumetric water content at 10 and 1000 kPa, respectively, and its effective water capacity in the 33–1500 kPa range was 17.9% higher than that of ST. At the same time, fine-particle enrichment in the bottom layer reduced wetting-front rise during capillary testing, indicating a trade-off between water storage and upward replenishment. Within the tested fine-particle range, moderate clay addition improved the hydraulic performance of sandy reconstructed soil, but soil design should balance precipitation retention, infiltration, and capillary supply. Because each treatment and soil-column configuration was represented by only one independently prepared experimental unit, experimental variability and reproducibility could not be evaluated. This study should therefore be regarded as a preliminary and exploratory laboratory assessment conducted under a specific set of material-preparation procedures, specimen geometries, and boundary conditions. The results describe specimen-level hydraulic contrasts rather than reproducible treatment effects and should not be directly generalized to field-scale soil reconstruction. They support a preliminary hypothesis for future replicated testing: fine-particle enrichment may increase water retention while slowing upward capillary replenishment. Full article

Understanding the spatiotemporal dynamics of land-use and cover change (LUCC) and ecosystem service (ES) responses is essential for assessing ecological functions in regional landscapes. However, conventional LUCC simulations often rely on historical trends and inadequately represent the spatially heterogeneous effects of top-down policy constraints. Taking the Henan section of the Yellow River Basin (HYRB) as a case study, we developed a policy-to-rule framework that translated ecological redlines, urban development boundaries, and restoration requirements into explicit spatial constraints and land-use transition rules in the PLUS model. A policy-constrained High-Quality Development Scenario (HQDS) was established, with the Natural Growth Scenario (NGS) as a reference. Five ESs were assessed using InVEST from 1985 to 2050, and the results were integrated with the Minimum Cumulative Resistance (MCR) model and circuit theory to construct an ecological security pattern (ESP). Historical reconstruction of the 2022 land-use pattern achieved an overall accuracy of 90.18% and a Kappa coefficient of 86.39%. The five ESs remained relatively stable overall: water yield, soil conservation, and the sediment-related indicator increased, whereas habitat quality and carbon storage declined slightly. Ecological source areas expanded from 7140.54 km² in 1985 to 12,039.17 km² under the HQDS in 2050, a 68.6% increase. Compared with the NGS, the HQDS increased source areas by 562.42 km² (4.9%), reduced ecological corridors from 26 to 24, and increased their total length from 1068.89 to 1099.61 km. These differences represent the projected, scenario-conditioned consequences of the specified policy constraints and provide quantitative decision support for future ecological management. Full article

Soil erosion on sloping cropland is a major threat to agricultural sustainability and ecological security in mountainous regions, yet its spatial distribution and landscape-level structural characteristics remain insufficiently quantified. Taking Zhaotong in northeastern Yunnan, China, as a typical mountainous agricultural region in the upper Yangtze River Basin, this study integrated Sentinel-2 imagery, high-resolution reference data, field survey information, the Google Earth Engine platform, a random forest classifier, the Chinese Soil Loss Equation, and landscape pattern metrics to assess soil erosion on sloping cropland. The land use classification achieved an overall accuracy of 90.70% and a Kappa coefficient of 0.88, providing a reliable basis for sloping cropland extraction. Sloping cropland covered 4218.77 km², accounting for 84.64% of total cropland area, but contributed 1.84 × 10⁷ t·yr⁻¹ of annual soil loss, equivalent to 97.51% of total cropland erosion. The mean erosion rate of sloping cropland reached 4260.50 t·km⁻²·yr⁻¹, and 95.84% of sloping cropland exceeded the soil loss tolerance threshold. County-level analysis revealed strong spatial heterogeneity, with high erosion risks concentrated in northern and eastern mountainous counties. Intensive, Severe, and Extreme erosion occupied only 26.14% of the sloping cropland area but contributed 62.21% of total soil loss. Landscape metrics further showed that Moderate erosion had the highest patch density and edge density, indicating a critical fragmentation stage in erosion development. These findings support a tiered conservation strategy in which high-intensity patches are prioritized for immediate sediment reduction, while fragmented Moderate-erosion (2500–5000 t·km⁻²·yr⁻¹) areas receive preventive management. The proposed framework provides a useful approach for identifying erosion hotspots and supporting targeted soil and water conservation in mountainous agricultural landscapes. Full article

The Southern Jiangsu hills region is located within the Yangtze River Delta Ecological Barrier. Soil erosion poses a threat to the development of commercial forests and the water quality of Lake Taihu, making it urgent to quantify the mechanisms by which vegetation and rainfall regulate slope erosion. This study established five standard runoff plots in Zhangzhu, Yixing, and continuously monitored runoff and soil loss from 2022 to 2023. By combining Random Forest modeling, partial least squares structural equation modeling (PLS-SEM), and moderation effect analysis, the study assessed the contributions of various driving factors under different rainfall types. The results indicate that the peach orchard (PEA + GRA) is an optimal ecological model, achieving runoff and sediment reduction rates of over 54.09% and 70.19%, respectively. Rainfall is the dominant factor driving runoff (r = 0.75), while the maximum 30 min rainfall intensity (I₃₀) is the dominant factor driving soil loss (r = 0.82). Furthermore, during low- to moderate-intensity rainfall events, vegetation attributes primarily govern hydrological responses; however, during extreme Type III rainstorms (24 h rainfall exceeding 50 mm), rainfall volume becomes the decisive factor. Moderation analysis further reveals that vegetation height and cover exert significant moderating effects on the initial transition phase from rainfall to runoff. These findings provide evidence-based guidance for optimal soil and water conservation strategy selection in subtropical hilly landscapes. Full article

Pisha sandstone (PS) is a weakly cemented soft rock widely distributed in the middle reaches of the Yellow River, China. PS disintegrates rapidly upon contact with water and has poor erosion resistance, making it a major source of coarse sediment in the Yellow River. However, PS is rich in aluminosilicate minerals and clay fractions, offering great potential as a sustainable precursor for geopolymer cementitious materials and as an amendment for degraded soils. The sustainable resource utilization of PS provides a new pathway for coordinated ecological and economic development in the PS areas. This paper first reviews the mineralogical and chemical characteristics of PS, clarifying that low diagenetic degree and high montmorillonite content cause poor erosion resistance, and that compound erosion from freeze–thaw, water, wind, and gravity erosion creates a superimposed amplification effect, which is the primary driver of severe soil erosion. Subsequently, three major control measures for soil erosion in the PS areas are summarized, namely biological measures using sea-buckthorn (Hippophae rhamnoides), chemical solidification, and microbially induced calcium carbonate precipitation (MICP), with analyses of their mechanisms, efficiency, and limitations. Furthermore, the research progress on the sustainable resource utilization of PS in the preparation of geopolymer cementitious materials and the amelioration of degraded soils is elaborated. Finally, future research directions are discussed to support the control of soil erosion and the green, sustainable resource utilization of PS. Full article

Soil erosion (SE) is a constant, complex land degradation process, a common natural disaster that occurs all over the world and severely impacts soil fertility, food security, and environmental balance. Soil erosion depends on many factors, including soil properties, slope, vegetation, rainfall amount and intensity, and anthropogenic activities. There are two main natural erosive forces by which soil is eroded and transported—water and wind. Water erosion refers to the detachment, transportation, and deposition of soil particles (solid runoff) into river networks. These particles, varying in size and composition, are the main products of soil erosion and most strongly affect river ecosystems. Solid runoff, or sediment-laden runoff, affects water quality, destroying habitats, carrying pollutants, reducing reservoir storage, and causing flooding. Erosion control activities also influence river ecosystems in different ways. Hydrotechnical facilities, a major erosion control practice, can alter the composition of aquatic biota by disrupting longitudinal connectivity and isolating populations. Reforestation and afforestation are other erosion control practices that have a strong impact on ecosystems. Stormwater retention systems in urban and forest areas are also important measures addressed in this review. This review examines complex environmental interactions and the roles of erosion and erosion control activities in river ecosystems. During the research, several key points were established: erosion and erosion control activities significantly affect river ecosystems. There is a lack of quantitative analysis of erosion intensity and its influence on ecosystems. This is probably due to the exceptional complexity and diversity of river ecosystems, but such a study would provide important information about complex relationships in nature. Full article

This study established a refined, distributed SWAT modeling framework that integrates elevation-band and snowmelt modules to reconstruct the alpine hydrological and sediment cycles of the Koshi River Basin (KRB) over the period 1990–2024, with climate scenarios constructed using the delta change approach. The KRB, a major transboundary watershed traversing China, Nepal, and India, was selected owing to its critical hydro-climatic role under the destabilizing “Asian Water Tower”; it generates substantial sediment yield, hosts the densest concentration of hydropower potential within the Ganges system, and spans an extreme vertical gradient from Mount Everest to the southern alluvial plains. Results reveal accelerated warming at a rate of 0.21 °C per decade and an overall warming–wetting trend, punctuated by an abrupt interdecadal shift around 2015. Precipitation dominated interannual streamflow variability, with enhanced rainfall triggering basin-wide sediment surges that overwhelmed the natural buffering capacity of the land surface. Conversely, rising temperatures intensified actual evapotranspiration, markedly depleting soil water and reducing total water yield and monsoon runoff, although sustained snow and glacier melt effectively elevated the dry-season low-flow baseline. The integrated climate forcing reshaped the disparity between hydrological extremes, imposing severe seasonal eco-hydrological stress that manifested as a pre-monsoon deficit in terrestrial green water and acute summer sediment outbursts for aquatic habitats. Furthermore, the flood regime exhibited an altered distribution, with mid-to-high frequency floods enhanced while low-frequency extreme flood peaks declined. The hydro-sedimentological regime consequently exhibits pronounced nonlinear responses to climate change, providing a critical, threshold-based scientific foundation for adaptive transboundary water resource management. Full article

Deep stormwater drainage tunnels are increasingly being used to mitigate urban flooding, but in-tunnel sediment deposition reduces their discharge capacity and complicates their maintenance. With direct field observation constrained, numerical simulation is essential, and river-based total sediment load formulas require reassessment for use in deep tunnels. The three-phase (air–water–sediment) CFD solver SedInterFoam is first validated against a benchmark open-channel suspended sediment experiment, and is then applied to a horseshoe tunnel under a fixed design discharge for multiple inlet sediment concentrations spanning urban stormwater conditions. Four classical formulas (Yang, Shen–Hung, Ackers–White, Engelund–Hansen) are evaluated at the CFD-resolved hydraulic state; Toffaleti is omitted because its zone-based formulation is incompatible with the partially filled horseshoe geometry. The CFD consistently shows persistent retention of a substantial fraction of the inlet sediment load, whereas the transport capacity-limited interpretation of the classical formulas predicts near-complete sediment throughput—indicating structural inadequacy for the dilute, supply-limited regime typical of urban stormwater. A Universal Soil Loss Equation (USLE)-style dimensionless deposition formula is therefore proposed, with inlet sediment loading as the explicit independent variable and a tunnel correction factor $K_{tunnel}$ absorbing the geometric, hydraulic, and sediment variations. Its regression yields an almost linear scaling and a nearly constant deposition ratio, while analysis of the internal flow and concentration fields shows that the retained sediment is strongly concentrated near the bed and that near-bed turbulent mixing weakens moderately with a rising inlet concentration. While calibrated for a single non-cohesive settleable sand fraction, the framework provides a transferable basis for inlet-loading-dependent deposition prediction in deep stormwater drainage tunnels, and subsequent extension of $K_{tunnel}$ to broader sediment conditions with field-based validation is expected to enable maintenance planning, dredging volume estimation, and sediment retention risk assessment. Full article

This study investigated the pollution characteristics, ecological risks, and sources of six trace elements in the water, riparian soils, and benthic sediments of the Taohuajiang lead–zinc mining area, Guangxi. Water, soil, and sediment samples were evaluated using pollution indices and source apportionment models. The results show zinc (Zn) is the primary water pollutant, spatially correlated with mining sites. Conversely, both soils and sediments exhibit severe composite contamination, with cadmium (Cd), lead (Pb), Zn, and silver (Ag) significantly exceeding background values. Notably, sediment trace elements accumulate intensely downstream of the mining zone and at river meander bends driven by hydrodynamic deposition. The area is classified as an extremely high risk zone (mean ecological risk index > 1200), predominantly driven by Cd. Source apportionment identified three factors governing the soils and sediments: legacy mining constitutes the principal source of Pb, Zn, Cd, Ag, and copper (Cu); natural geological processes govern arsenic (As); and agricultural/domestic activities partially contribute to Cu and Ag. Overall, historical mining primarily drives the regional contamination across multi-phase media, which is further exacerbated by agriculture, collectively threatening the local benthic and terrestrial ecosystem. Full article

Intensive agriculture, deforestation, and frequent land-use changes contribute to increased soil erosion and sediment transport from both arable and non-arable lands into minor river channels. These factors directly and indirectly influence riverbank erosion and, in turn, sediment transport in rivers. Evidence on anthropogenic land-use/land-cover (LU-LC) change impact remains limited in both quantitative and spatial terms within the Danube River Basin. The study area includes research results from 17 locations concerning satellite-derived LU-LC changes along the Romanian sector of the Danube River, as well as validation results with particular highlighting on the Corabia area, Romania. According to results derived from combining LU-LC products based on Copernicus satellite data (comparing the years 2000 and 2018) and validated in the field through UAV flights conducted in 2025, the conversion of riparian vegetation into cultivated or uncultivated land accelerates bank failure. This is particularly evident where agricultural areas are located in the immediate vicinity of riverbanks. Such bank failures can be attributed to a reduction in root cohesion and a decrease in soil–bank structural stability. As a consequence, sediment delivery to the river channel increases via overland flow. The workflow proposed in this study offers a transferable and adaptable solution for areas with similar characteristics for a multitemporal approach regarding the influence of agricultural lands especially on sediment transport and riverbank erosion. Full article

Massive nutrient inputs from different land uses have caused eutrophication in the Yangtze River. River sediment, as a sink for terrestrial nutrients, can sustain eutrophication for a long time. To further improve water quality, sediment organic carbon (TOC), nitrogen (TN), phosphorus (TP), and the impact of land use composition were investigated in the Tuojiang River watershed, once the most polluted tributary of the Upper Yangtze River. Results showed that the average TOC, TN, and TP contents were, respectively, 11.4 g/kg, 1078 mg/kg, and 1170 mg/kg higher than the local soil background value or the ecologically safe level limit. Due to the spatial layout of agriculture and industry, sediment nutrients were higher in the tributaries and the upper reaches of the main stream of the Tuojiang River. Regression analysis identified that TN was primarily affected by the composition of the dry-farm field within the 500 m zone along the river system, and TOC was affected by 1000 m of dry-farm field and 100 m of paddy field, while TP was related to the distribution of the phosphate chemical industry. It also enhances the urgency of reducing nutrient loss from agricultural non-point sources and mitigating residual nutrients in river sediment. Full article

Rainfall-induced erosion poses a serious threat to river levee slopes, where raindrop impact and surface runoff trigger particle detachment, rill initiation, and gully development, leading to rapid soil loss and local instability. This study experimentally evaluated short-fiber reinforcement as an erosion-control measure for levee slopes under controlled rainfall conditions. Laboratory embankment models were constructed using a uniform soil mixture and compacted under consistent moisture conditions. Simulated rainfall was applied at intensities of 50 and 100 mm/h. Erosion progression was monitored through time-series observations and quantified using sediment collection and three-dimensional surface measurements. Comparative tests were performed on unreinforced and fiber-reinforced slopes to examine the influence of fiber bridging and surface anchoring on the initiation and development of erosion. The results showed that short-fiber reinforcement delayed rill formation and reduced soil loss. Under 50 mm/h rainfall, 1% coir fiber reduced the eroded mass by approximately 70%, whereas polypropylene fiber achieved approximately 42% reduction compared with the unreinforced control. These findings suggest that short natural fibers can effectively enhance the erosion resistance of compacted levee slopes under rain. Full article