In order to explore the influencing factors and spatial differences of the green development of agriculture (GDA) in the Yellow River Basin (YRB), and to provide theoretical support and decision-making basis for the high-quality development of agriculture in the YRB, an evaluation index system for the level of GDA was established, which included three dimensions of high efficiency of development, ecological friendliness and resources conservation. Based on the panel data of 68 prefecture-level cities in the YRB from 2011 to 2021, the global entropy method (GEM) was applied to assess the level of GDA in the YRB, and the Moran index was used to analyze the spatial and temporal patterns of its differentiation. On this basis, six indicators were set up in economic, social and natural aspects, including industrial structure, planting structure, industrialization level, urbanization level, topographic relief and annual precipitation, and a multi-scale geographically weighted regression (MGWR) model was used to empirically analyze the influencing factors of the GDA in the YRB and its spatial differences. The results show that a) the level of GDA in the YRB shows an upward trend from 2011 to 2021, but the overall level at the end of the study period is still low, with the level of GDA in the lower reaches significantly higher than that in the middle and upper reaches, the development of efficient dimensions in the upper reaches and lower reaches showing a clear upward trend, and the ecologically friendly and resources-saving dimensions showing a smaller increase in the study period. b) There is an obvious positive spatial correlation between the level of GDA in the YRB, with a relatively large number of H-H agglomeration and L-L agglomeration prefecture-level cities. c) The spatial heterogeneity of the factors influencing the GDA is significant and the intensity of influence is different, among which the spatial differences in the influence of industrial structure, planting structure, industrialization level and topographic relief are small and the spatial difference in the influence of urbanization and annual precipitation is large. Industrial structure, industrialization level and topographic relief have negative effects, while planting structure, urbanization level and annual precipitation have positive effects. The intensity of influence is topographic relief > industrialization level > urbanization level > industrial structure > planting structure > annual precipitation. Some suggestions are put forward, such as changing the concept of agricultural development, strengthening regional cooperation and implementing differentiated agricultural green development strategies.

In order to explore the development level and regional differences of new-quality-productivity in the nine provinces (regions) of the Yellow River Basin and provide a reference for the high-quality-development of new-quality-productivity in the Yellow River Basin, this paper built an evaluation index system of new-quality-productivity development level from the three dimensions of new workers, new labor objects and new labor materials. Based on the panel data from 2013 to 2022, the entropy value method was used to measure the development level of new-quality-productivity in the nine provinces (regions) of the Yellow River Basin, and the nuclear density estimation, σ convergence test and β convergence test, spatial correlation analysis and diagnosis of main obstacle factors were carried out. The results show that a) from 2013 to 2022, the development level of new-quality-productivity in the nine provinces (regions) of the Yellow River Basin shows an increasing trend year by year, among which Qinghai and Gansu have relatively low development level of new-quality-productivity, while Shandong and Shaanxi have relatively high development level of new-quality-productivity. b) There are obvious differences in the development level of new-quality-productivity in the upper, middle and lower reaches of the Yellow River, among which the lower reaches of the Yellow River is always much higher than that in the upper and middle reaches, and the upper reaches of the Yellow River is always lower than that in the middle and lower reaches, but the difference among provinces (regions) is decreasing, the phenomenon of multi-polarization is weakening, and there is a “catch-up effect” and the development of new-quality-productivity in each province (region) will be affected by neighboring provinces (regions). c) From the three dimensions of the development of new-quality-productivity, the new labor object dimension is the “weak side” that needs to be strengthened in the development of new-quality-productivity in the Yellow River Basin. From the perspective of the evaluation indicators of new-quality-productivity, forest coverage rate, R&D personnel full-time equivalent, the number of authorized domestic invention patents, the added value of tertiary industry, traffic network density, the revenue proportion of software and information technology service industry, industrial structure, and environmental protection efforts are the main factors restricting the development of new-quality-productivity in the nine provinces (regions) of the Yellow River Basin. At the end of the paper, some suggestions are put forward, such as attaching importance to personnel training, strengthening environmental protection, encouraging scientific and technological innovation and accelerating industrial upgrading.

Facing the national strategic requirements of improving the ecological environment quality and high-quality development in the Yellow River Basin, in order to promote the conservation and intensive utilization of water resources, this paper constructed 15 evaluation indexes including water resources system, socio-economic system and ecological environment system. The entropy weight method was used to evaluate the water resources conservation and intensive utilization level of 50 cities in the upper and middle reaches of the Yellow River Basin from 2018 to 2021, and identified the main factors affecting the water resources conservation and intensive utilization level of cities in the study area by using obstacle model. The results show that the overall level of conservation and intensive utilization of water resources in the study area is on the rise, from 0.505 in 2018 to 0.553 in 2021. The utilization rate of reclaimed water, the proportion of agricultural water use and the sewage treatment rate are the main obstacle factors affecting the improvement of the level of conservation and intensive utilization of water resources in the study area. Based on this analysis, the countermeasures for the conservation and intensive utilization of water resources were put forward from four aspects of water saving, social and economic development, ecological environment protection and unconventional water resources utilization.

In order to investigate the effect and mechanism of digital economic development on carbon emission in the Yellow River Basin, based on the panel data of 76 prefecture-level cities in the Yellow River Basin from 2011 to 2020, we measured the level of digital economic development, the total amount of carbon emission and the intensity of carbon emission in the Yellow River Basin, and built an individual and time two-way fixed-effects model to conduct empirical analysis, and conducted robustness tests on the results of the lagging effect of digital economic development, changing the sample capacity, and substitution variables. The empirical results are tested for robustness such as lagged effect of digital economic development, changing sample capacity, and substitution of variables, the mechanism of technological progress and industrial structure upgrading, and the heterogeneity of location and heterogeneity of resource endowment of carbon emission reduction effect of digital economic development. The results show that a) the digital economic development has a significant inhibitory effect on carbon emission intensity and total carbon emission in the Yellow River Basin. b) Technological progress and industrial structure upgrading are important mechanisms for digital economic development to promote carbon emission reduction in the Yellow River Basin. c) There is significant location heterogeneity and resources endowment heterogeneity in the inhibitory effect of digital economic development on carbon emission in the Yellow River Basin, and the inhibitory effect on carbon emission in the middle and upstream areas of the Yellow River is significantly better than that in the downstream areas, and the inhibitory effect on carbon emission in the middle and downstream areas is significantly worse. The inhibition effect on the total carbon emissions in the middle and upper reaches of the Yellow River is significantly better than that in the lower reaches, the inhibition effect on the carbon emission intensity in the upper reaches has not yet appeared, and the inhibition effect on the carbon emissions of non-resources cities is significantly greater than that of resources cities. Countermeasures and suggestions are put forward to coordinate the coordinated development of the digital economy in the Yellow River Basin, strengthen the promotion of green and low-carbon technological innovation, accelerate the transformation and upgrading of the industrial structure, implement differentiated digital economy development strategies, and effectively curb carbon emissions.

The Xiaolangdi Reservoir is a key project for controlling water and sediment of the Yellow River. Studying its sediment discharge law and regulation indicators is of great significance for maintaining effective storage capacity in the long term. Based on the analysis of measured data and the practice of water and sediment regulation, 34 sediment discharge processes in the Xiaolangdi Reservoir from 2010 to 2023 were selected, and the reservoir sediment discharge law and its influencing factors were analyzed, in the meantime the regulation indicators which were useful to reducing reservoir silt were proposed. The results show that, during water and sediment regulation in pre-flood season, sediment discharge is mainly caused by flushing of clear water discharged by the Sanmenxia Reservoir. The sediment discharge amount is positively linear correlated with the inflow volume and negatively linear correlated with the storage volume of the Xiaolangdi Reservoir. During water and sediment regulation in flood season, the sediment discharge ratio is negatively correlated with the degree of reservoir damming and the ratio of inflow and outflow flow, which is a power function relationship. The quantitative expressions of sediment discharge amount during water and sediment regulation in pre-flood season and sediment discharge ratio during water and sediment regulation in flood season are established, and the water level of the reservoir can be reduced and then maintained to 215 m and 223 m respectively during water and sediment regulation in pre-flood and flood season are proposed, in which the annual sediment discharge ratio can reach 125%.

In order to address climate change and water resources pressures, and to achieve sustainable regional water resources utilization under the carbon neutrality target, the InVEST model was employed to assess carbon storage and water yield in the Qinhe River Basin from 2000 to 2020. The study also used geographical detectors to explore the driving factors and explanatory power, and spatial autocorrelation analysis to examine the spatial relationship between the two. The results show that: a) Water yield in the Qinhe River Basin has shown a fluctuating increasing trend, rising from 1.020 billion m³ in 2000 to 1.167 billion m³ in 2020. This change aligns with the trend in precipitation, with carbon storage and potential evapotranspiration being the main driving factors. b) Carbon storage decreases from 167.566 7 million tons in 2000 to 167.110 5 million tons in 2020, following a trend similar to soil carbon storage, with potential evapotranspiration and water yield being the primary driving factors. c) The global Moran’s index of water yield and carbon storage is -0.2, showing no significant spatial distribution overall. Spatially, there is a pattern of high water yield-low carbon storage and low water yield-high carbon storage.

In recent years, there has been an increase in extreme rainfall events, and flood risk remains the biggest threat to the Lower Yellow River. Therefore, it is of great significance to study the changes in the flood characteristics of the Lower Yellow River for flood disaster prevention and reduction. This study analyzed variations in flood peak flow and sediment concentration during different periods by using measured flow and sediment data from the Huayuankou Hydrological Station from 1974 to 2020. The dynamic time warping algorithm was employed to calculate asynchronous duration in the wandering reach of the Lower Yellow River, with the changes in hydro-sedimentary asynchronous characteristics and their influencing factors investigated. The research results show that the floods in the braided reach of the Lower Yellow River are mainly of medium size. After the operation of the Xiaolangdi Reservoir, the proportion of low sediment concentration flood events reaches to 85.9%. The average peak-shape coefficient decreases to 1.33, and the main type of flood asynchrony has been changed from the synchronous type of flood peak and sediment peak to the lagging type of sediment peak. The relationship between the lag duration of sediment peak lagged-type floods and influencing factors were analyzed, such as incoming sediment coefficient, duration and sediment type coefficient. A formula for calculating lag duration was established, with computed values generally aligning well with measured values.

In order to study the impact of the operation of cascade reservoirs in the upper reaches of the Yellow River on the hydrological regime of the downstream section, the Longyangxia Reservoir to Liujiaxia Reservoir section was taken as the research area, the Mann-Kendall mutation test was used to examine the years of abrupt changes in the average annual flow of the inflow and outflow hydrological stations (Tangnaihai, Guide, Xunhua, and Xiaochuan hydrological stations) from 1952 to 2021, the hydrological change index method-hydrological change range method (IHA-RVA method) was used to quantitatively evaluate the hydrological change degree of the monthly average flow of the inflow and outflow hydrological stations, Pearson correlation analysis method was used to evaluate the correlation between annual runoff and annual sediment discharge at the inflow and outflow hydrological stations. The results show that the flow of hydrological stations entering and leaving the reservoir exhibits periodic changes and overall increases, while the annual average flow of the upper reaches of the Yellow River undergoes a sudden change after the operation of the cascade reservoirs. After the operation of the reservoir, the monthly average flow of hydrological stations located upstream of the reservoir shows moderate to low changes, while the monthly average flow of hydrological stations located downstream of the reservoir shows moderate to high changes. The monthly average flow change is related to the “flood storage and dry discharge” operation mode of the reservoir. The annual sediment discharge of the inflow and outflow hydrological stations shows a decreasing trend, with the Tangnaihai Hydrological Station in the upstream showing the smallest decrease in sediment discharge, and the Xiaochuan Hydrological Station in the downstream showing the largest decrease in sediment discharge. The annual runoff is significantly positively correlated with the annual sediment discharge.

There is independence and integration between water supply and sediment reduction in sediment-laden river reservoirs. How to maintain effective storage capacity and meet water supply requirements for a long time is one of the issues to be solved in the efficient operation of sediment-laden river reservoirs. In this paper, Dongzhuang Reservoir of Jinghe River was taken as the research object. Through the analysis of measured data and mathematical model calculation, the measured hydrological sediment and cross-section erosion and deposition in the lower reaches of Jinghe River and Weihe River were analyzed. The reservoir sediment discharge flow index which was beneficial to reduce the sediment deposition in the lower reaches of Weihe River and maintain the effective reservoir capacity for a long time was studied, and the joint regulation mode of reservoir runoff and sediment was put forward. The outcomes show that during the main flood season for the sediment interception period from July to September, when the inflow is greater than 600 m³/s and the sediment concentration is greater than 300 kg/m³, the Dongzhuang Reservoir is open for sediment discharge. As the normal operation period, during the main flood season from July to September, when the inflow exceeds 300 m³/s, the Dongzhuang Reservoir will open for sediment discharge. The reservoir cannot supply water during the sediment discharge period. The joint regulation of the Dongzhuang Reservoir and the surrounding four storage reservoirs can reduce the deposition of the lower reaches of the Weihe River by 11 million tons per year, increase the guarantee rate of agricultural irrigation from 30% to 50%, and increase the guarantee rate of industrial water supply from 57% to 95%.

he formation and evolution of the Ω-shaped channel of the Yellow River depend on the boundary morphology and interactions of the tectonic belts around the Ordos block. The collision, subduction, compression, strike-slip and whirl effects of the peripheral tectonic belt on the block have made the Yinchuan Graben, Hetao Graben, Jin-Shaan Gorge and other tectonic landforms through the Yellow River. The highly developed fault zone, cataclastic rock zone and dense joint zone in graben and canyon have strictly controlled the extension and bend of the channel. In Neoid period, the extrusion of the Indian Plate in NE-trending and the Pacific Plate in NW-trending has compounded new activities of the peripheral major fault, which has controlled and constrained the Ω-shaped channel of the Yellow River.

Taking the Yellow River Basin in Shandong Province as the research object, six categories of indicators were proposed, and the AHP-TOPSIS method was used to allocate the water rights of the nine cities along the Yellow River Basin in Shandong Province in 2025. On this basis, the quota method was used to analyze the water resources carrying threshold of each city in 2025, and the current carrying state was analyzed. The results shows that a) the water use rights of agriculture, industry, living and ecological industries in 9 cities along the Yellow River are 9.828 billion m³,2.515 billion m³, 2.752 billion m³ and 1.477 billion m³, respectively. b) The carrying threshold of population size in 9 cities is 45.195 5-59.562 0 million, among which Jinan has the largest upper limit of carrying threshold. The threshold of industrial added value is 1 654.037-1 935.323 billion yuan, with an overall increase of 15%-35 %; the carrying threshold of irrigated cultivated land area is 2.285 5-3.795 4 million hectares, and only Heze and Dongying exceed the upper limit of the threshold. The threshold of urban construction land is 384.2-625.5 thousand hectares. The current value of Binzhou exceeds the upper limit of the threshold, and Zibo is close to the upper limit. c) The population size and irrigated cultivated land area carrying status of 9 cities are the weakest in the southwest of Shandong Province. Compared with the current situation, the industrial added value has increased by different degrees, all of which are in a loadable state. The carrying capacity of urban construction land in southwest Shandong is the best, and the carrying capacity of Binzhou and Zibo is the worst.

In order to analyze the changes of water demand of energy resources-based cities in the “Ji-shaped bend” of the Yellow River, based on the water Economy Kuznets Curve-WEKC, the relationship between per capita water consumption and per capita GDP in 14 resources-based cities along the Yellow River during 2000-2022 was analyzed. The variation characteristics of regional water use were further extracted by variational mode (VMD) decomposition, and the future water demand was predicted by support vector regression (SVR). The results show that the WEKC curve of the “Ji-shaped bend” of the Yellow River energy resources-based cities in the study period presents a variety of connection patterns consisting of U-shaped and inverted U-shaped, and will continue to show an interweaving pattern of water demand growth and decline. The WEKC curve is characterized by fluctuation and shows periodicity and regularity with economic development, which is helpful for in-depth exploration of the evolution law of water demand in the course of regional development. Based on the research conclusions, relevant suggestions are put forward for the future research direction of WEKC curve.

In order to provide a reference for building the ecological compensation mechanism in the Yellow River Basin from the perspective of taxation, especially the horizontal ecological compensation tax mechanism, this paper analyzed the limitations of the existing ecological compensation schemes such as vertical ecological compensation from higher governments to lower governments, intra-provincial (regional) horizontal ecological compensation and inter-provincial (regional) horizontal ecological compensation in the Yellow River Basin, and put forward the idea of “fee to tax” for horizontal ecological compensation in the Yellow River Basin. From the perspective of tax regulation, the advantages of tax compensation in external governance, system design, vertical and horizontal complementarity and rebuilding of central-local relationship of ecological compensation were discussed. In terms of mechanism design, the corresponding analysis was made between water resources tax, environmental protection tax and ecological compensation tax and the key areas of ecological compensation, such as water conservation, cross-province (region) boundary water pollution, soil and water conservation and ecological compensation integrated management. Integrating the design of tax system into the ecological compensation mechanism could give full play to the regulating role of tax revenue, so that the horizontal ecological compensation mechanism can play a key role in the ecological function and economic and social development of the upper, middle and lower reaches of the Yellow River Basin.

Influenced by external conditions such as climate and river channels, ice-run disasters in the Inner Mongolia section of the Yellow River are characterized by strong suddenness and destructiveness, which brings great pressure to ice prevention in the Yellow River. Especially, the Shisifenzi bend in the Toudaoguai section of the Yellow River in Inner Mongolia is very easy to become the initial ice-run position every year due to the influence of multiple factors such as the shrinkage of the river channel, the increase of the ice volume from the upper reaches and the morphology of the river channel. In this paper, in view of the frequent occurrence of flooding disaster and the difficulty of risk prevention and control in the Shisifenzi section of the Yellow River in Inner Mongolia, based on the measured topography and water depth data of the river channel and using the hydrodynamic module and particle tracking module of MIEK21, a coupled numerical model of ice-run was constructed, and a simulation analysis was carried out on the Shisifenzi River section of the Yellow River to study the trajectory of ice-run under the conditions of different incoming ice quantities and the densification of the ice. The result reveals that the ice movement law in Shisifenzi section of the Yellow River.

In order to solve the coordination problem between agricultural green development and ecological protection in the Yellow River Basin and identify the reasons behind the contradiction between agricultural production and ecological environment protection, the paper took the nine provinces (regions) in the Yellow River Basin as the research object to build an evaluation index system for agricultural green development and ecological protection was constructed. The entropy method was used to measure the agricultural green development index and ecological protection index of each province (region) from 2006 to 2020. The fusion coordination model was used to calculate the coupling coordination between agricultural green development and ecological protection, and the obstacle degree model and grey correlation degree model were used to diagnose and analyze the obstacles and driving factors of coupling coordination development. The results show that during the research period, the coupling coordination degree between agricultural green development and ecological protection in the Yellow River Basin shows an overall upward trend, with a spatial pattern of “upstream>downstream>midstream”. There is still a significant gap between each province (region) and high-quality coordinated development. The coordinated development of agricultural green development and ecological protection is mainly hindered by the dimensions of output efficiency and resources endowment. The internal driving factors that affect the degree of coupling and coordination between agricultural green development and ecological protection in the Yellow River Basin, in descending order of correlation, are the proportion of nature reserves area, the multiple cropping index of arable land, forest coverage, grain yield per unit area, per capita arable land area and fertilizer application intensity. Therefore, it is necessary to strengthen the overall coordination of agricultural industry development planning in the upper, middle, and lower reaches of the Yellow River Basin, accelerate the flow of factors such as technology, capital, and labor between regions, and formulate differentiated agricultural development and ecological civilization construction strategies.

Using remote sensing technology to dynamically monitor the utilization type of the Yellow River embankment-line is helpful to understand the construction process of ecological corridor along the Yellow River. This paper took the middle reaches of the Yellow River as the research object, extracted embankment-line utilization information at intervals of 5 years based on Landsat-5 TM and Landsat-8 OLI images from 1993 to 2023, analyzed the spatial-temporal variation characteristics of embankment-line utilization after the implementation of the national strategy of ecological protection and high-quality development in the Yellow River Basin and preliminarily discussed the effectiveness of ecological protection of the Yellow River corridor. The results show that from 1993 to 2023, the proportion of living embankment-line in the middle reaches of the Yellow River is increased from 2.12% to 16.96%, and the proportion of ecological embankment-line shows a fluctuating upward trend, reaching 39.68% in 2023. The embankment-line utilization of three sections in the middle reaches of the Yellow River is quite different, among which, the ecological embankment-line is mainly used in the Jin-Shaan Valley section, the agricultural embankment-line is mainly used in the Fen-Wei Plain section, and the Sanmenxia-Taohuayu section has changed from an agricultural embankment-line to an ecological embankment-line. From 2018 to 2023, the increase of ecological embankment-line and living embankment-line and the decrease of agricultural embankment-line are the most significant, and the ecological embankment-line of each section shows positive changes.

In order to enrich the study of carbon ecological security and high-quality development in resources-based cities of the Yellow River Basin and provide the basis for promoting the construction of ecological civilization and high-quality development, the evaluation index system was built. The level of coupling coordination and its spatial-temporal differences and spatial agglomeration characteristics from 2012 to 2021 were analyzed by the coupling coordination model and the spatial autocorrelation model. The results show that the level of coupling coordination for carbon ecological security and high-quality development of resources-based cities in the Yellow River Basin from 2012 to 2021 has been increasing year by year, with the growth rate in the middle reaches being faster than that in the upstream and downstream. The spatial agglomeration effect of coupling coordination is significant for carbon ecological security and high-quality development in resources-based cities, which is characterized by a “fluctuating upward trend”. Coupling coordination between carbon ecological security and high-quality development in most resources-based cities are distributed in “high-high and low-low” agglomeration areas, and is characterized as a “belt like” distribution. It is suggested that resources-based cities in the Yellow River Basin give full play to their comparative advantages, formulate differentiated plans, strengthen division of labor and cooperation, enhance regional correlation, exert a radiating effect and promote coordinated development, so as to achieve the coordinated advancement of carbon ecological security and high-quality development throughout the basin.

As a supporting project of the Xiaolangdi Key Water Control Works, the Xixiayuan Counter-Regulation Reservoir suffers significant loss of effective storage capacity, directly affecting the comprehensive benefits of the reservoir. Accurate calculation of floodplain and main channel evolution is crucial for the operation and management of the reservoir. On the basis of a one-dimensional mathematical model of reservoir water and sediment, this study proposed a calculation method for floodplain and main channel evolution in the Xixiayuan Reservoir, drawing on the calculation method for river floodplain and main channel evolution. The calculation method was applied to the floodplain and main channel evolution of Xixiayuan Reservoir in 2018 and 2020. The reliable results in the reservoir area confirmed the feasibility of the method.

In order to calculate the maximum population scale and economic scale that the urban water resources in Qingdao City can support, and to formulate the urban development model for urbanization and sustainable utilization of water resources, the entropy weight method was used to measure the water resources carrying capacity and urbanization level of Qingdao City from 2015 to 2022. A system dynamics model was built from both water resources and social economy aspects, and the water supply and demand situations of four development models (natural development, rapid development, water conservation priority, and comprehensive development) from 2023 to 2030 were simulated. The results show that the water resources carrying capacity of the urban area of Qingdao City shows a fluctuating upward trend from 2015 to 2022, and the urbanization level is steadily increased. The comprehensive development is the optimal mode of the urbanization development in Qingdao City, which can ensure that there is still a surplus water resources after meeting the needs of residents' life and economic development.

The river regime of the wandering reach of the Lower Yellow River changes violently. Studying its stability is of great significance for the regulation of the lower reaches of the river channel. The variation process of wandering intensity in wandering reach from 1986 to 2020 and its influencing factors were investigated by analyzing the measured data and then the wandering reach stability was predicted by the one-dimensional water and sediment mathematical model under the different sediment scenarios of 300, 600 and 800 million tons with considering Guxian Reservoir constructed or not in the future. It finds out that the lateral and vertical wandering intensity of the braided reach considerably decreases since the operation of Xiaolangdi Reservoir while there is a slight increase in vertical wandering intensity from 2018 to 2020 because of the large amount of sediment discharged by the Xiaolangdi Reservoir. And the lateral wandering intensity of the wandering reach shows an upward trend with the increase of bankfull width and shows a downward trend with the bankfull water depth increasing. What’s more, Guxian Reservoir can maintain a certain scale of normal water channel in the wandering reach for a long time and significantly promote the comprehensive stability coefficient of the wandering reach compared without the Guxian Reservoir. Under the scenarios of 600 million and 800 million tons of incoming sediment, the time for the comprehensive stability coefficient to be greater than 25 is extended by 24 and 25 years respectively. Under the scenario of 300 million tons of incoming sediment, the comprehensive stability coefficient can be maintained greater than 0.030 for a long time.

Juxtaposed ice, consolidated ice and open water are the main ice types during the frozen-up period alone the Inner Mongolia section of the Yellow River. The distribution and area of the ice types are important ice condition information that needs to be mastered for ice prevention decision-making. Taking the formation and characteristic analysis of river ice types in Inner Mongolia as the entry point, using support vector machine and random forest as classifiers, and multi-band spectra, multi-band spectra +NDSI+NDFSI, and multi-band spectra + texture features as feature vectors, six experimental schemes were combined, and classification experiments and accuracy evaluations of river ice surface types were conducted based on the high-resolution remote sensing images of ZY-3. The results show that a) the supervised classification scheme using support vector machines as classifiers and multi-band spectra+NDSI+NDFSI as features has the highest overall accuracy for river ice type classification, especially improving the recognition ability of consolidated ice and open water. b) Comparing with the near-infrared single band threshold method, supervised classification with SVM and RF has higher accuracy in classifying river ice types in high-resolution images. This study has provided a method for automatic classification of river ice types in domestic high-resolution remote sensing images.

山西省万家寨引黄工程泵站压力隧洞(竖井)建成后,砼裂缝较为密集,部分隧洞充水后发生明显漏水.经反复处理后情况虽有所改善,但仍未完全奏效.经分析,裂缝与水泥用量较大、不设伸缩缝、隧洞超挖以及施工质量控制不严等因素有关,建议采取合理分缝、降低水泥用量、改进泵送砼施工工艺以及加强缺陷处理等措施.在内水压力较高的情况下,钢衬仍不失为最安全可靠的设计方案.

In order to investigate the influence of land use change to the basin flood process, the Fenhe River Basin was chosen as the study area. The SWAT model and the extreme land use scenario analysis method were employed to analyze the effects of land use type changes on the flood process in different periods and scenarios. The results show that a) the mean value of Nash-Sutcliffe Efficiency(E_NS) is greater than 0.70 and the mean value of determination coefficient (R²) is greater than 0.65 during the calibrated and validated period, indicating that the SWAT model has good applicability in the Fenhe River Basin. b) Between 2000 and 2020, there is a reduction in the area of cultivated land, grassland, water bodies and unused land, while the area of forested land and built-up land is increased. c) Under the land use in 2000, 2010 and 2020, each peak flow and the total flood volume show a slight upward trend. d) Under the arable land scenario, there is an increasing trend in each peak flow and its total flood volume; while under both the woodland and grassland scenarios, there is a decreasing trend. In terms of magnitude of impact, land use type change has a smaller impact on larger flood processes and a larger impact on small and medium flood processes. Therefore, it is necessary to increase the area of forest and grass and vegetation coverage, promote water-appropriate planting, and avoid high-water-consuming vegetation in areas with high incidence of flood disasters and serious soil erosion, so as to improve the ability of flood control, flood resistance, disaster prevention and mitigation in Fenhe River Basin, and promote ecological restoration and high-quality development in Fenhe River Basin.

The Yellow River runoff has unsteady and non-linear characteristics. In order to provide reference for ensuring water security in Henan Province, the non-flood season discharge of Sanmenxia Hydrology Station of the Yellow River was studied. The paper built non-flood season runoff prediction models by combining variational mode decomposition (VMD) with long short term memory (LSTM) and support vector regression (SVR). The sparrow search algorithm (SSA) was used to adjust the model parameters to improve the prediction accuracy. The runoff data was decomposed into multiple eigenmode functions (IMF) by the VMD algorithm, Euclidean distance between components was calculated based on K-Means clustering method and the reciprocal of Euclidean distance was used as the weight of each component. Finally, the results of each component were put into LSTM/SVR for model prediction, and the runoff results were obtained by weighted reconstruction of the predicted values of components. Comparing with before and after weighted VMD-SSA-LSTM and VMD-SSA-SVR model, the results show that the proposed K-Means weighted VMD-SSA-LSTM model predicts the average daily runoff of Sanmenxia Hydrology Station from January 2003 to May 2023 (non-flood season month), with the mean absolute error being 82.54 m³/s, the root-mean-square error being 106.64 m³/s and the fitted coefficient being 0.92, the trend of runoff can be predicted more effectively.

General Secretary Xi Jinping proposed to adhere to the principle of “defining city, land, population and production by water”(referred to as “Four Waters and Four Determinations”), at the symposium on ecological protection and high-quality development in the Yellow River Basin in China. In order to provide theoretical guidance and reference for ecological protection and high-quality development in Gansu Province, the Yellow River Basin, and even the water-scarce areas in the northern China, as well as to implement the “Four Waters and Four Determinations” policy, taking the Yellow River Basin in Gansu Province as a representative of water-scarce areas in northern China, this paper analyzed the characteristics and main water issues of the region, as well as the new situation and strategic position it faced. The current situation of water resources management in the Yellow River Basin in Gansu Province was analyzed, and strategic countermeasures for innovative management of the “Four Waters and Four Determinations” policy in the Yellow River Basin of Gansu Province under the new situation were proposed, including carrying out top-level design, strengthening rigid constraints on water resources, promoting key technology research and development and engineering construction, establishing a sound management system and mechanism, and promoting pilot projects. The core of implementing the “Four Waters and Four Determinations” in water-scarce areas of northern China is to use water resources as a rigid constraint, optimize the development pattern of ecology, energy and food, make the scale of population, urban, irrigation, and industrial development coordinated with water resources conditions, enhance the compatibility of water with city, land, population and production development, and fundamentally promote the harmonious development of human and water resources.

In order to study the characteristics of river regime change during Diaokou River flow and the influence of human activities to the flow path evolution after the flow stopped, based on the measured data analysis, the paper compared and analyzed the water and sediment conditions, the horizontal and vertical geometry of the Diaokou River and the changes of erosion and deposition in two different stages of the Diaokou River during the river running from 1964 to 1976 and after the river stopped running from 1976 to now. The results show that during Diaokou River flow, the evolution of the flow path is influenced by the factors of water and sediment conditions, channel morphology and tidal current dynamics, and the flow path evolution goes through three stages of the initial stage channel wandering and swinging, the middle stage channel being single and straight, and the final stage channel branching out. After the stop of the flow of the Diaokou River, it is affected by human activities, resulting in significant changes in the terrain of the river, the main channel shrank and the river beaches crisscrossed. In the future, the Diaokou River control should focus on prominent issues such as channel deposition and shrinkage, estuarine and coastal erosion, and human activities. Engineering measures such as dredging channel and optimizing ecological water supplement should be taken, and gradually restore ponds to rivers, reclaimed land to wetland and farmland to beach in an orderly manner.

Based on the theoretical of eigenvalue buckling analysis method and considering the material utilization efficiency of chord member structures, this study employed numerical simulation method to conduct stability calculations for gate arms without chord member, with single chord member, and with double chord members. The influence of chord member positioning, quantity, and cross-sectional properties on the structural stability of steel gate arms was analyzed. An optimized chord-layout scheme was proposed, and on this basis, finite element analysis was conducted on the overall stability of the steel gate support arm. The results indicate that for single chord member gate arms, the optimal ratio of the distance between the chord and the hinged support to the total arm length (l/m) ranges from 0.60 to 0.75, achieving the highest load-bearing capacity per unit mass. Arranging double chord members away from the hinge end can improve the unit mass bearing capacity of the support arm, but the spacing between chord members should not be too large. Dimensional analysis of the chord member structure reveals that when the width-to-height ratio of the chord is 1.4, the overall stability of the gate arm is favorable. The thickness ratio of the flange to the web (t₃/t₄) has minimal effect on the load-bearing capacity per unit mass, with the primary design consideration being to ensure local stability of the gate arm. Adding chord members improves gate stiffness and enhances the stress state, primarily by reducing the maximum equivalent stress in the steel gate arm. Compared to gate arms without chord member, single chord member arms reduce the maximum equivalent stress by 8.44%, while double chord member arms achieve a reduction of 12.99%.

The air and water environmental pollution problems caused by the energy-based industrial structure and coal-based energy consumption in the Yellow River Basin are one of the constraining factors for green, low-carbon, and high-quality development. Urban agglomeration integration is a process in which multiple cities collaborate in the economic, social, infrastructure, environmental protection and other aspects to enhance the overall sustainable development ability. As of 2023, there are four national-level urban agglomerations approved by the State Council located in the Yellow River Basin. In order to explore the impact of urban agglomeration integration on low-carbon development in the Yellow River Basin, based on the theoretical mechanism analysis and the panel data of 80 prefecture-level cities in the Yellow River Basin from 2011 to 2022, the implementation of the national-level urban agglomeration policy was regarded as a quasi-natural experiment. That is, the prefecture-level cities in the Yellow River Basin included in the development plans of the four national-level urban agglomerations were taken as the experimental group, and the remaining prefecture-level cities as the control group. A multi-period difference-in-differences model was used for regression to explore the impact of urban agglomeration integration on low-carbon development in the Yellow River Basin, and parallel trend tests, robustness tests, mechanism tests, and spatial spillover effect tests were carried out.The results show that: a) Urban agglomeration integration can significantly promote low-carbon development in the Yellow River Basin; b) Urban agglomeration integration promotes low-carbon development in the Yellow River Basin by promoting industrial structure upgrading and technological innovation. Human capital and environmental regulation have a significant positive regulatory effect on the promotion of low-carbon development by urban agglomeration integration; c) The impact of urban agglomeration integration on low-carbon development has a significant positive spatial spillover effect, and the geographical distance threshold for the spatial spillover effect is 200 km.At the end of the article, suggestions are put forward, such as further promoting the all-round development of urban agglomeration integration, improving government efficiency, dredging the two intermediary channels of industrial structure upgrading and technological innovation, and giving full play to the regulatory role of human capital and environmental regulation.

In order to deeply explore the characteristics and driving factors of runoff changes in the Shiyang River basin, and provide a scientific basis for basin management planning and ecological environment building, this study utilized the runoff data from 1956 to 2019 and applied mathematical statistics to analyze the runoff characteristics, in conjunction with meteorological data to assess the impact of climate change on runoff. The findings reveal that a) a decreasing trend in runoff volumes for the Gulang River, Huangyang River, Zamu River and Jinta River, while the runoff of Dajing River and Xiyang River remains relatively stable. b) The basin exhibits periodic changes over 2 to 10 years and 10 to 30 years. c) Apart from the Dongda River and Xida River, which lack significant abrupt change years, other rivers in the basin have notable abrupt changes in runoff between 1970 and 1990. d) The precipitation variation trends in the Shiyang River Basin are not significant, while the temperature has significantly increased. e) Based on the division of change points, the runoff reduction between the baseline and the change period ranges from 13.78% to 37.43%, with human activities identified as the key factor causing runoff reduction and changes.

In order to explore the evolution characteristics of runoff in the Yellow River basin, this paper analyzed the natural runoff data of Huayuankou Hydrological Station from 1919 to 2016 for nearly 100 years. The order of clustering analysis, MannKendall mutation test and sliding taverage method were used to analyze the mutation points of the runoff sequence in Huayuankou Hydrological Station. Linear trend regression test, MannKendall trend test and Spearmann rank correlation test were used to analyze the trend of the runoff series before and after the mutation point. The results show that the runoff mutations in the Yellow River basin were relatively obvious at 1933-1934 and 1989-1990. The mutation of the former is mainly caused by largescale changes in natural factors (such as temperature, precipitation), and the latter is mainly caused by changes in the basin scale of artificial factors (water use increasing and the bottom surface changing). In 1919-1933, the trend of runoff change is relatively significant, passed 0.10 of the significant level test, showing a downward trend. In 1934-1989 and 1990-2016, the trends of runoff changed are more smoothly.

In order to coordinate the relationship between water resources and economic and social development in the Yellow River Basin, based on the current water consumption data of the Yellow River Basin in Shandong Province from 2008 to 2022, the evolution characteristics and spatial distribution law of water consumption structure in the Yellow River Basin in Shandong Province were analyzed by using the methods of information entropy and equilibrium degree, Lorenz curve and Gini coefficient. The results show that the agricultural water use in the Yellow River Basin in Shandong Province no longer has a single absolute advantage, and the water resources allocation is transforming into multi-objective. The information entropy and equilibrium degree show a synchronous upward trend, indicating that the distribution of various types of water consumption is developing towards uniformity. From 2008 to 2022, the spatial equilibrium degree of agricultural water use in the Yellow River Basin of Shandong Provinceis is decreased obviously, the spatial equilibrium degree of industrial water use is increased slightly, the spatial equilibrium state of domestic water use does not change greatly, and the spatial equilibrium degree of ecological water use is increased obviously. From 2008 to 2022, the spatial distribution of agricultural water use in the Yellow River Basin in Shandong Province changs from an obvious equilibrium state to a relatively balanced state, while the spatial distribution of industrial and domestic water use has always been relatively balanced, and the spatial distribution of ecological water use has changed from a poor equilibrium state to a relatively balanced state. The proportion of agricultural water in Dezhou is the highest, the proportion of industrial water in Zibo is obviously higher than that in other regions, and the proportion of domestic water in Jinan is the highest and slowly rising. In 2018, the proportion of ecological water in Jinan is the highest, and the proportion of ecological water is the lowest in Dezhou.

In order to solve the issue of uneven subsidence of the channel, serious subsidence and slide of the concrete lining plate in the collapsible loess area, the reasons for subsidence of the No.10 main canal in Guhai extention irrigation in Ningxia were analyzed, and the foundation soil of the channel was ramped, and the bearing capacity of the foundation soil was increased. The channel subsidence is treated by arc bottom trapezoidal concrete section, composite geomembrae and benzene plate. The results show that the density of the channel reaches more than 1.78 g/cm³, the pore ratio of the base soil is greatly reduced, and the density is increased. The cast-in place arc bottom trapezoid section has good structural loading condition and uniform adjustment of frost heave force and uneven subsidence. The analysis of the effect after the reconstruction and treatment of the channel shows that the water content of the foundation soil, the frost heaving amount and the settlement amount of the concrete slab has been effectively controlled. Through the comprehensive treatment of collapsible channels, the theoretical design and methods for the treatment of collapsible channels and the collapse of concrete slabs are improved.

In order to explore the impact of digital economic development on energy efficiency in the Yellow River Basin and its internal influence mechanism, based on the panel data of 80 prefecture-level cities in the Yellow River Basin from 2011 to 2021, the three-stage DEA method was used to measure energy efficiency, and the entropy method was adopted to measure the development level of the digital economy. Taking the development level of the digital economy as the explanatory variable and energy efficiency as the explained variable, taking the level of financial development, the size of urban population, government fiscal expenditure, the level of science and technology expenditure, and the level of urbanization as control variables, the level of technological innovation, the level of industrial structure upgrading, and the intensity of environmental regulation as mediating variables, and the level of economic development as moderating variables, an individual fixed effect model was built to empiratically test the impact of digital economic development on energy efficiency. And the mediating effect, moderating effect and heterogeneity analyses were conducted. The results indicate that a) the development of the digital economy has a U-shaped impact on the improvement of energy efficiency in the Yellow River Basin, with an initial inhibitory effect followed by a promotional effect. Currently, the level of digital economy development in the Yellow River Basin still inhibits the enhancement of energy efficiency. b) Technological innovation, industrial structure upgrading, and environmental regulation partially mediate the impact of the digital economy on energy efficiency. c) The level of economic development negatively moderates the U-shaped relationship between digital economy development and energy efficiency, meaning that the impact of digital economy development on energy efficiency diminishes as the level of economic development increases. d) The impact of digital economy development on energy efficiency exhibits regional heterogeneity and heterogeneity in economic development levels. Currently, more cities in upstream areas experience improved energy efficiency due to digital economy development, followed by midstream areas, with downstream areas showing the least. The U-shaped impact of digital economy development on energy efficiency is more pronounced in relatively economically underdeveloped areas compared to relatively developed areas. At the end of the paper, the relevant countermeasures and suggestions are put forward.

This paper analyzed the existing problems of the risk control of small reservoirs and the legal path of management. Small reservoirs predominantly depend on temporary document issuance system and comprehensive legislation such as the Water Law of the People’s Republic of China and Flood Control Law of the People’s Republic of China, as well as administrative regulations such as the Regulations on the Safety Management of Reservoir Dams of the People’s Republic of China for risk management, gradually forming path dependence and giving rise to problems such as insufficient institutional effectiveness, incomplete long-term mechanisms, and loopholes in the reservoir legal system. For the risk control of small reservoirs, in addition to technical hazard elimination and reinforcement of dangerous reservoirs, it is also urgent to break the constraints of the management path of small reservoirs, reconstruct the awareness of reservoir risk prevention and control, strengthen the management system and mechanism of reservoirs, and enhance the legal capacity of reservoir risk control through the formulation of the Reservoir Law.

Under the influence of climate change and human activities, the runoff of most rivers in Shanxi Province has been severely attenuated. Four typical watersheds in Shanxi province, including Fenhe, Qinhe, Zhanghe and Hutuo rivers, were taken as the research objects. The runoff evolution characteristics were analyzed. The hydrological processes were simulated by using the VIC model, based on which the contributions of climate change and human activities to runoff attenuation were analyzed. The results show that the annual runoff of typical watersheds shows a significant downward trend during 1956-2018, and all of which has an abrupt change around 1980. Compared with the baseline period (1960-1980), the average annual runoff (1981-2000) of Fenhe, Qinhe, Zhanghe and Hutuo rivers is decreased by 57.9%, 49.1%, 57.3% and 37.6%, and the contributions of human activities are 59.9%, 54.3%, 52.3% and 49.0% respectively. During 2001-2018, the attenuation is increased further, and the contribution of human activities increases to 74.8%, 73.1%, 72.4% and 57.7% respectively. Human activities such as surface and underground water extraction, coal mining, soil and water conservation measures and so on are the main driving factors of runoff attenuation.

In order to explore the possibility and impact of digital inclusive finance's intervention in agricultural green development in the Yellow River Basin, based on panel data from nine provinces (regions) in the Yellow River Basin from 2013 to 2021, the entropy method was employed to measure the level of agricultural green development. Fixed-effect and mediation-effect models were utilized to investigate the effect and mechanism of digital inclusive finance on agricultural green development. The results indicate that the comprehensive score of agricultural green development level exhibits a pattern of higher scores in Sichuan, Shandong and Henan. Digital inclusive finance and its three sub-dimensions significantly promote agricultural green development. Agricultural technology plays a bridging role between digital inclusive finance and agricultural green development. The development of digital inclusive finance in the Yellow River Basin is conducive to promoting the level of agricultural green development. Therefore, it is necessary to further strengthen the promotion of digital inclusive finance in the Yellow River Basin, fully leverage its role in enhancing agricultural technology, inject new vitality into agricultural green development, and promote ecological protection and high-quality development in the Yellow River Basin