Search Results (18)

Flooding frequency in the lower Yellow River (YR) exhibited an abrupt increase post-934 CE, causing catastrophic societal disruptions. However, the quantitative relationship between this abrupt increase and the intensification of human activity in the midstream Loess Plateau (LP)’s Primary Sediment Source Area (PSSA) remains uncertain. This study systematically evaluates the threshold effects of human activities on YR flooding through multi-proxy historical records, GIS-based spatial analysis, and nonparametric statistical tests. The results show that from 934 to 1102 CE, the population density in the PSSA surged from 1.3 to 19.8 persons/km² (a 14.2-fold increase, p = 0.005). A 2400-year-scale comparison using 934 CE as the breakpoint revealed that the mean population density in this region increased from 5.2 to 51 persons/km² (a 9.8-fold increase). This dramatic population surge drove a 1.4-fold increase in the cultivation rate (from 8.6% to 20.5%), leading to a 5.4-fold rise in sediment yield (1.6 × 10⁸ → 1.02 × 10⁹ t/yr, p = 0.035), a 10-fold acceleration in downstream sedimentation rate (0.3 → 3.3 cm/yr, p = 0.001), and ultimately a 5.5-fold escalation in flooding frequency (from 1.6 to 10.4 events per 20 years, p < 0.0001). The study identifies 19.8 persons/km² as the ecological pressure threshold. It proposes converting population density to ecological pressure equivalents adjusted for soil–water conservation coverage (e.g., terracing/afforestation). When the equivalent ecological pressure exceeds 19.8 persons/km², pre-defined sediment control measures (e.g., tillage restrictions/afforestation mandates) should be enforced in the PSSA. Full article

The Loess Plateau is threatened by severe gully erosion and tableland retreat, primarily driven by uncontrolled surface runoff. Numerical simulations of Gully Consolidation and Highland Protection (GCHP) demonstrate that individual measures such as check dams, terraces, and gully head backfilling can reduce sediment by 31–35% in the short term, but their effectiveness declines after approximately 10 years. This study classifies GCHP models into four types, progressively integrating drainage, filling, slope protection, and ecological measures. Simulation results confirm that the most comprehensive model—coupling all four types—offers the highest and most sustainable effectiveness in both erosion control and ecological restoration. To address long-term challenges, the study proposes a Sustainable Natural GCHP Management Method, combining cascade interception, guided drainage, and ecological retention, thereby enhancing project resilience and supporting China’s Yellow River Basin ecological protection strategy. Full article

Research on the runoff and sediment reduction effects of soil and water conservation measures has always been a topic of interest, which is of great significance for carrying out sustainable strategies for soil and water conservation in the Yellow River Basin. This study aims to find the threshold years of soil and water conservation measures for reductions in runoff and sediment. Through the analysis of various soil and water conservation measures, runoff, sediment, and rainfall data in the Sanchuan River Basin from 1960 to 2019, we determined the threshold years of soil and water conservation measures on runoff and sediment processes using the Hydrology and Lagrange Multiplier method. The results are as follows: The trend in flood season rainfall and annual rainfall in the Sanchuan River Basin is consistent. The 1990s was a turning period in the annual rainfall and flood season rainfall of the Sanchuan River Basin. The 2000s was a turning period of the runoff in the Sanchuan River Basin, while the sediment entered a stable period after 2000. The best periods for reducing runoff and sediment were the initial treatment period (1967–1979) and the centralized treatment period (1980–1996). The runoff and sediment reduction effects of each soil and water conservation measure during the initial treatment period (1967–1979) were terrace (32.8%) > dam (30.1%) > grass (18.6%) > forest (18.5%), while their effects during the centralized treatment period (1980–1996) were grass (53.7%) > terrace (20.7%) > dam (14.6%) > forest (11.0%). The runoff and sediment reduction effects of various soil and water conservation measures during different treatment periods indicate that the runoff reduction effect reached its peak in 2003–2005, while the sediment reduction benefit reached its peak in 2013–2015. Based on the comprehensive benefits of runoff and sediment regulation, 2013–2015 are considered to be the threshold years for various soil and water conservation measures, with the measures covering respective average areas of 4.85 × 10⁴, 17.80 × 10⁴, 1.15 × 10⁴, and 0.82 × 10⁴ hm². These research results will have a certain significance for the reasonable allocation of soil and water conservation measures and sustainable development in the Yellow River Basin. Full article

Abstract: In the context of the large-scale management of the Loess Plateau and efforts to reduce water and sediment in the Yellow River, this study focuses on a typical watershed within the Loess Plateau. The potential for vegetation restoration in the Kuye River Basin is estimated based on the assumption that vegetation cover should be relatively uniform under similar habitat conditions. The potential for terrace restoration is assessed through an analysis of topographic features and soil layer thickness, while the potential for silt dam construction is evaluated by considering various hydrological and geomorphological factors. Based on these assessments, the overall potential for soil erosion control in the watershed is synthesized, providing a comprehensive understanding of target areas for ecological restoration within the Kuye River Basin. The study demonstrates that the areas with the greatest potential for vegetation restoration in the Kuye River Basin are concentrated in the upper and middle reaches of the basin, which are in closer proximity to the river. The total potential for terracing is 1013.85 km², which is primarily distributed across the river terraces, farmlands, and gentle slopes on both sides of the riverbanks. Additionally, the potential for the construction of check dams is 14,390 units. The target areas for terracing measures in the Kuye River Basin are primarily situated in the middle and lower reaches of the basin, which are in closer proximity to the river. Conversely, the target areas for forest, grass, and check dams, as well as other small watershed integrated management measures, are predominantly located in the hill and gully areas on the eastern and southern sides of the basin. The implementation of the gradual ecological construction of the watershed, based on the aforementioned objectives, will facilitate the protection, improvement, and rational utilization of soil, water, and other natural resources within the watershed. Full article

Investigating the changes in the runoff and sediment coupling relationship in the Middle Yellow River Basin of China can not only deepen the understanding of soil loss control in arid areas, but also help solve key issues of regional ecological protection. Since the 1960s, soil- and water-conservation projects have been implemented in the Middle Yellow River Basin, inducing a significant reduction in runoff and sediment and changes in the relationship between runoff and sediment. The study identified the change points of coupling relationship between runoff and sediment in the Wuding River Basin (WRB) by constructing a diagnostic method based on coupling coordination degree and the Pettitt test; the study validated this using the Copula function and analyzed the impacts of erosion energy and underlying surface factors. The results showed the following: (1) the method based on coupling coordination degree and the Pettit test could accurately reflect the coupling relationship of runoff and sediment and identify two change points (1971 and 1996); (2) runoff and sediment in the WRB decreased gradually over three periods (P1, 1960–1970; P2, 1971–1995; P3, 1996–2020), with an average annual runoff of 15.34 × 10⁸, 10.72 × 10⁸, and 8.32 × 10⁸ m³ and average annual sediment load of 1.84 × 10⁸, 0.82 × 10⁸, and 0.32 × 10⁸ t, respectively; (3) the maximum possible joint design value of runoff and sediment under different return periods in P1 were all the highest, followed by P2 and P3, and the larger the return period, the higher the maximum possible joint design value; (4) runoff erosion power could promote runoff and sediment in PE (1960–2020), P1, P2 and P3 at a significant level, check dams and terrace could decrease runoff and sediment significantly in PE, and the highest contribution to runoff reduction was check dam (95.4%), while the highest contribution to sediment reduction was REP (93.8%). The study can provide a new way to analyze the changes in the runoff and sediment relationship and provide scientific support for runoff and sediment regulation in the Middle Yellow River Basin. Full article

The Amarillo River in Famatina, La Rioja, Argentina, is a natural acidic river with distinctive yellow-ochreous iron precipitates along its course. While mining activities have occurred in the area, the river’s natural acidity is influenced by environmental factors beyond mineralogy, where microbial species have a crucial role. Although iron-oxidising bacteria have been identified, a comprehensive analysis of the entire microbial community in this extreme environment has not yet been conducted. In this study, we employ high-throughput sequencing to explore the bacterial and fungal diversity in the Amarillo River and Cueva de Pérez terraces, considered prehistoric analogues of the current river basin. Fe(II)-enrichment cultures mimicking different environmental conditions of the river were also analysed to better understand the roles of prokaryotes and fungi in iron oxidation processes. Additionally, we investigate the ecological relationships between bacteria and fungi using co-occurrence and network analysis. Our findings reveal a diverse bacterial community in the river and terraces, including uncultured species affiliated with Acidimicrobiia, part of an uncharacterised universal microbial acidic diversity. Acidophiles such as Acidithiobacillus ferrivorans, the main iron oxidiser of the system, and Acidiphilium, which is unable to catalyse Fe(II) oxidation but has a great metabolic flexibility,, are part of the core of the microbial community, showing significant involvement in intraspecies interactions. Alicyclobacillus, which is the main Fe(II) oxidiser in the enrichment culture at 30 °C and is detected all over the system, highlights its flexibility towards the iron cycle. The prevalence of key microorganisms in both rivers and terraces implies their enduring contribution to the iron cycle as well as in shaping the iconic yellow landscape of the Amarillo River. In conclusion, this study enhances our understanding of microbial involvement in iron mineral precipitation, emphasising the collaborative efforts of bacteria and fungi as fundamental geological agents in the Amarillo River. Full article

The Yellow River Basin (YRB) is a crucial ecological zone and an environmentally vulnerable region in China. Understanding the temporal and spatial trends of terraced-field areas (TRAs) and the factors underlying them in the YRB is essential for improving land use, conserving water resources, promoting biodiversity, and preserving cultural heritage. In this study, we employed machine learning on the Google Earth Engine (GEE) platform to obtain spatial distribution images of TRAs from 1990 to 2020 using Landsat 5 (1990–2010) and Landsat 8 (2015–2020) remote sensing data. The GeoDa software (software version number is 1.20.0.) platform was used for spatial autocorrelation analysis, revealing distinct spatial clustering patterns. Mixed linear and random forest models were constructed to identify the driving force factors behind TRA changes. The research findings reveal that TRAs were primarily concentrated in the upper and middle reaches of the YRB, encompassing provinces such as Shaanxi, Shanxi, Qinghai, and Gansu, with areas exceeding 40,000 km², whereas other provinces had TRAs of less than 30,000 km² in total. The TRAs exhibited a relatively stable trend, with provinces such as Gansu, Qinghai, and Shaanxi showing an overall upward trajectory. Conversely, Shanxi and Inner Mongolia demonstrated an overall declining trend. When compared with other provinces, the variations in TRAs in Ningxia, Shandong, Sichuan, and Henan appeared to be more stable. The linear mixed model (LMM) revealed that farmland, shrubs, and grassland had significant positive effects on the TRAs, explaining 41.6% of the variance. The random forest model also indicated positive effects for these factors, with high R² values of 0.984 and 0.864 for the training and testing sets, respectively, thus outperforming the LMM. The findings of this study can contribute to the restoration of the YRB’s ecosystem and support sustainable development. The insights gained will be valuable for policymaking and decision support in soil and water conservation, agricultural planning, and environmental protection in the region. Full article

The study of the classification and failure modes of Yellow River terrace landslides under the influence of irrigation projects is of key importance to alleviate the paradox between the rapid evolution of terrace landscapes caused by landslides and the survival of local residents. However, such studies remain controversial, despite it being widely recognized that a rise in groundwater level caused by irrigation is a key factor associated with landslide failure modes. In this paper, we take the Heitai terrace as a case study. Using aerial images and field investigations, we classify landslides in the Heitai loess layer into type A landslides (not related to groundwater) and type B₁ and B₂ landslides (related to groundwater). We analyze the failure modes and disaster-causing characteristics of each type of landslide, and our results indicate that the attenuation in soil strength is a key factor common to both type A and type B landslides, based on which type A landslides with small volume and short sliding distance are able to block the previous spring discharge, causing a rise in localized groundwater, which further contributes to type B landslides; the location of previous type B₁ landslides with a large volume and long sliding distance and type A landslides may be more susceptible to type B₂ landslides with a small volume and short sliding distance, where there are low confining pressures during the lower soil shear process. Therefore, we believe that the inevitable interaction effects between the failure modes of landslides during landslide evolution, which govern the geomorphological evolution of the Heitai terrace, are unavoidable. Combining these data with numerical analyses, we further demonstrate that a rise in groundwater level and discontinuous attenuation of soil strength caused by changes in soil properties during irrigation together control terrace landslides and their failure modes. From the results of interferometric synthetic aperture radar time-series monitoring of Yellow River terrace activity with and without irrigation projects, and electrical resistivity tomography groundwater detection, we conclude that in the future, Heitai terrace will continue to experience a high intensity of landslide activity, and conditions for the most catastrophic type of landslide (type B₁) will remain, including the high localized groundwater caused by previous landslides, and the discontinuous attenuation of soil strength caused by the deterioration in soil properties. In this context, we believe that slope-cutting engineering will be one of the most economical means to achieve future landslide-type transformation on the Heitai terrace; this will mitigate the process of geomorphological evolution and improve the human living environment. Full article

The variation of river hydrologic process can reflect the impact of not only natural factors, but also human activities. The purpose of this study is to reveal the change in the hydrologic regime of the Yellow River and its response to ecological protection. Based on the daily water and sediment observation data of representative gauging stations of the Yellow River, we analyzed the variation of the annual and monthly runoff and suspended sediment load (SSL), as well as monthly mean runoff, suspended sediment transport rate (SSTR), sediment inflow coefficient, and hydrological regime in a decadal average of the gauging stations during the period of 1960–2019. The results showed that the variation of annual runoff and SSL, as well as the monthly mean runoff and SSTR in a decadal average, had a significant decreasing trend in the 1960s–1990s, which was mainly in response to the gradual implementation of ecological protection measures such as afforestation, terrace construction, check dam construction, etc., in the basin. In 2000s and 2010s, the annual runoff increased, while the SSL increased slightly. This was a response to the implementation of new river management measures such as ensuring the ecological water demand of the lower reaches and scouring the riverbed by manually regulated water discharged from the Xiaolangdi Reservoir. At the same time, the monthly mean runoff and SSTR for the flood season (July–October) decreased remarkably while the process curve of the monthly mean discharge and sediment concentration changed from a clockwise loop to a counterclockwise loop in the river reach below the Xiaolangdi dam. This was a comprehensive response to the environmental protection measures in the Yellow River basin, in which the construction and operation of the Xiaolangdi Reservoir played a key role. This study can provide reference for river basin management. Full article

Chinese loess provides the most detailed terrestrial records of paleoclimate changes. We employed the grain-size components of aeolian sediments to reconstruct the history of the East Asian winter monsoon (EAWM) on the Chinese Loess Plateau (CLP). Here, using the grain-size class vs. standard deviation method, we extracted the environmentally sensitive grain-size components of nine last glacial loess sections. The grain-size class vs. standard deviation diagrams showed two major grain-size components (fine and coarse), which varied from section to section. Material resource distances and post-depositional pedogenesis were the main factors affecting environmentally sensitive grain-size components. The coarse grain-size components of the Yulin, Baicaoyuan, Xifeng, and Luochuan sections were influenced by the transportation distance, while we attributed the fine grain-size components of the Weinan, Shaoling, Duanjiapo, and Chaona sections to pedogenesis. At the same time, the Mianchi section’s sensitive grain-size component was also coarse, and was affected by the local circulation from the nearby Yellow River terrace. Our comparison of sensitive grain-size components and EAWM revealed that the coarse grain-size components were progressively finer along with the EAWM from the northwest to the southeast on the CLP, and they can be regarded as the most suitable proxy indicator of the EAWM on the CLP. Full article

Residents living in areas with high fluorine environmental background will ingest excessive fluorine from the atmosphere, drinking water, food and other ways. Long-term effects of fluorine on the human body could cause people suffering from dental fluorosis and influence the sustainable development of the severe fluorosis areas. Previous studies have independently discussed the high fluoride environment in Dali County from the aspects of natural environment, drinking water quality and endemic fluorosis. This study carried out a detail investigation on dental fluorosis population in seven selected villages of Dali County, Shaanxi province, northwest China. The highest dental fluorosis index of 1.9 was found in Lianjia village located near the Anren depression, while the lowest dental fluorosis index of 0.0 was found in Jiaxi village near the Yellow River alluvium. Groundwater fluorine contents the range was 0.01 mg/L to 11.80 mg/L, with the highest value (2.6 mg/L) being observed in the 2nd terrace of Weihe River. The lowest groundwater fluorine content (0.8 mg/L) was observed in the Yellow River alluvium. Soil fluorine contents ranged from 1.18 mg/kg to 13.70 mg/kg, with its highest value (13.70 mg/kg) observed in Xinfeng village near the Anren depression. The lowest value of fluorine (1.18 mg/kg) was found in soil from the 1st terrace of Weihe River. As for the fluorine contents of corn, they ranged from 4.04 mg/kg to 7.72 mg/kg. The highest value (7.72 mg/kg) appeared in the 3rd terrace of Weihe River and the lowest value (4.04 mg/kg) in the 2nd terrace of Weihe River. The soil leaching was the dominant fluorine source of groundwater environment. Areas with severe dental fluorosis are located at the edge of the depression and the conjunction between steep slope and gentle slope. A poor correlation was found between the dental fluorosis index from the seven investigated villages and the corn fluorine content contrarily to the groundwater fluorine content, which positively correlated to the dental fluorosis index. Based on the obtained results, two recommendations were done to prevent and control dental fluorosis and accelerate the sustainable development in Dali County: to strengthen the use of low fluorine groundwater for drinking water supply, and to widely install the public water purifiers in the rural communities for purifying high-fluorine water to reduce the incidence of dental fluorosis in the population. Full article

The Shuanghuaishu (SHS) site in China is one of the 100 most important archaeological discoveries over the past 100 years; its historical heritage can be traced directly back 5300 years. Understanding the early landscape of the site would provide important information about the origin of Chinese civilization. The SHS site is buried and surface traces are difficult to see; therefore, we attempted to reconstruct the early landscape of the site based on a current surface landscape model and environmental archaeological analysis. We created a modern three-dimensional (3D) landscape model of the study area from high spatial resolution unmanned aerial vehicle (UAV) aerial photographs and analysed the distance change between the Yellow River and SHS site in the past 60 years from CORONA and Landsat images. By combining environmental archaeological survey results, archaeological excavation data, relevant papers, and field measurements, we reconstructed the paleotopography of the SHS site during the Yangshao period (7000–5000 aBP). On this basis, 3D natural and human landscapes during the Yangshao period were rebuilt. The results show that (1) Satellite images acquired at different resolutions can provide multiscale spatial information about the site, and high-precision models of current conditions can be quickly generated from UAV aerial photography. (2) From 1960 to 2020, the shortest distance between the SHS site and the Yellow River was approximately 512 m. The location of bedrock on Mang Mountain can be used to infer the early extent of the northern terrace at the site. (3) Environmental archaeology provided information about the palaeoenvironment of the site area. By incorporating spatial information technology and 3D visualization, we can better restore the early landscape of the SHS site. Our work integrates environmental archaeology, field archaeology, and spatial technology, enabling data and modelling support for the visual interpretation of the SHS site. Full article

The Wufo Basin at the margin of the northeastern Tibet Plateau connects the upstream reaches of the Yellow River with the lowland catchment downstream, and the fluvial terrace sequence in this basin provides crucial clues to understand the evolution history of the Yellow River drainage system in relation to the uplift and outgrowth of the Tibetan Plateau. Using field survey and analysis of Digital Elevation Model/Google Earth imagery, we found at least eight Yellow River terraces in this area. The overlying loess of the highest terrace was dated at 1.2 Ma based on paleomagnetic stratigraphy (two normal and two reversal polarities) and the loess-paleosol sequence (12 loess-paleosol cycles). This terrace shows the connections of drainage parts in and outside the Tibetan Plateau through its NE margin. In addition, we review the previously published data on the Yellow River terraces and ancient large lakes in the basins. Based on our new data and previous researches, we conclude that the modern Yellow River, with headwaters in the Tibet Plateau and debouching in the Bohai Sea, should date from at least 1.2 Ma. Ancient large lakes (such as the Hetao and Sanmen Lakes) developed as exorheic systems and flowed through the modern Yellow River at that time. Full article

Changes in the land use/cover alter the Earth system processes and affect the provision of ecosystem services, posing a challenge to achieve sustainable development. In the past few decades, the Yellow River (YR) basin faced enormous social and environmental sustainability challenges associated with environmental degradation, soil erosion, vegetation restoration, and economic development, which makes it important to understand the long-term land use/cover dynamics of this region. Here, using three decades of Landsat imagery (17,080 images) and incorporating physiography data, we developed an effective annual land use/cover mapping framework and provided a set of 90 m resolution continuous annual land use/cover maps of the YR basin from 1986 to 2018 based on the Google Earth Engine and the Classification and Regression Trees algorithm. The independent random sampling validations based on the field surveys (640 points) and Google Earth (3456 points) indicated that the overall accuracy of these maps is 78.3% and 80.0%, respectively. The analysis of the land system of the YR basin showed that this region presents complex temporal and spatial changes, and the main change patterns include no change or little change, cropland loss and urban expansion, grassland restoration, increase in orchard and terrace, and increase in forest during the entire study period. The major land use/cover change has occurred in the transitions from forests, grasslands, and croplands to the class of orchard and terrace (19.8% of all change area), which not only increase the greenness but also raised the income, suggesting that YR progress towards sustainable development goals for livelihood security, economic growth, and ecological protection. Based on these data and analysis, we can further understand the role of the land system in the mutual feedback between society and the environment, and provide support for ecological conservation, high-quality development, and the formulation of sustainable management policies in this basin, highlighting the importance of continuous land use/cover information for understanding the interactions between the human and natural systems. Full article

Landslide exposes the previously blocked groundwater discharge. High concentrations of soluble salt form salt sinters that can be observed near discharge passages. Based on existing laboratory investigation results of soil leaching and shearing reported in the literature, the effect of the soluble salt loss via spring water on irrigation-induced landslide deformation was studied under large-scale conditions. During our field investigation of landslides in the Heitai terrace of the Yellow River’s upper reaches in Gansu Province, China, 35 spring outlets were found, and the Heitai terrace was divided into five subareas, based on the difference in spring flow. Deformation data for the terrace were obtained by small baseline subset technology (SBAS-InSAR). These data were analyzed in combination with the amount of soluble salt loss, to explore the correlation between the deformation of the landslide and the soluble salt loss in the loess irrigation area. The results showed that the cumulative deformation and the loss of soluble salt were increasing continuously in the terrace. Although the increasing intensity of each subarea was different, the changing intensity of the two during the corresponding monitoring period was highly consistent. The statistical analysis revealed a strong positive correlation between the accumulated loss of soluble salt via spring water and the accumulated displacement of the terrace edge (p < 0.01). After the slope k between the two was tested by the Grubbs test and t-test, the k was no abnormality (α = 0.05) and difference (Sig > 0.05), further providing the basis for confirming the existence of this positive correlation. When the loss of soluble salt in rock and soil increased gradually, the accumulated deformation of the terrace edge also increased continuously. The findings of this study are of great significance for understanding the formation mechanism of landslides and the identifying landslide revival in irrigation areas of the Loess Plateau. Full article