Clarifying the specific strategies for enhancing the resilience of the “water-energy-grain-carbon” system in the context of high-quality development in the Yellow River Basin is of great value for achieving ecological protection and high-quality development strategies in the Yellow River Basin. By comprehensively utilizing social network models， interpretive structural models， entropy weight methods based on game theory， and obstacle degree models， this study explores the action path of influencing factors on the resilience of the “water-energy-grain-carbon” system in the Yellow River Basin. Based on the analysis of the spatial pattern of resilience in the “water-energy-grain-carbon” system in the Yellow River Basin in 2021， the key obstacles to system resilience are diagnosed， and corresponding resilience improvement strategies are proposed by combining the factor pathways and causal attributes of the influencing factors. The research has found that： ① The main obstacles to the resilience of the “water-energy-grain-carbon” system in the Yellow River Basin are the total power of agricultural machinery， the total capacity of built reservoirs， per capita water resources， recycled water production capacity， per capita energy production， and comprehensive groundwater production capacity. Except for per capita water resources， other factors exist as causal factors in the system. The five main obstacle factors belong to the bottom and middle layers in the explanatory structural model， which play a driving role in the overall resilience level of the “water-energy-grain-carbon” system； ② During the research period， the water resource subsystem had the highest degree of obstacles， and most of the obstacles that hindered the resilience development of the “water-energy-grain-carbon” system in the Yellow River Basin belonged to the water resource subsystem. The obstacle level of the water resource subsystem in the middle reaches was higher than that in the upstream and downstream areas， and the obstacle level of the energy and food subsystems in the upstream was greater than that in the middle and downstream areas. The difference in the degree of carbon subsystem barriers is relatively small， and the rate in the middle reaches is higher than the average level.

In the context of global warming， the advancement of vegetation spring phenology due to rising temperatures is well documented. Climate warming also leads to increases in soil moisture （SM） deficit and vapor pressure deficit （VPD）. However， as necessary water conditions for vegetation growth， their effects on vegetation spring phenology remain unclear. Therefore， based on the solar-induced chlorophyll fluorescence （SIF） data set， this study extracted the parameters of the start of the season （SOS） of vegetation in spring in China from 2001 to 2018 through the Polyfit-derivative method， the double-logistic Maximum Curvature method and the Timesat method. Secondly， the VPD values of the study period were calculated by using the China meteorological forcing dataset and Penman formula. Finally， Teil-Sen Median trend analysis， Mann-Kendall test and sensitivity analysis were used to clarify the spatio-temporal variation rules of SOS， VPD and SM， and to reveal the influence mechanism of spring SM and VPD on SOS. The results show that： ① SOS first gradually delays with the increase of latitude， and starts to fluctuate steadily at the north of 35°N， with an average SOS on the 130th day of the year； ② In spring， SM and VPD showed a large area of non-significant drying trend， soil moisture decreased at a rate of 0.037 m³/（m³?10 a）， VPD increased at a rate of 0.34 hPa/10 a， and SOS showed a large area of non-significant advance trend at a rate of 5.1 d/10 a. ③ SOS in arid areas were most sensitive to the changes of SM and VPD in spring， and with the decrease of SM gradient in spring， the importance of VPD to SOS gradually increased， and the importance of SM gradually decreased. This study is important for understanding and predicting the response of vegetation growth to the change of water conditions under the background of global warming， and for formulating policies to deal with climate change， and can provide scientific basis for ecological environment construction in China.

Flood disaster assessment can directly show the intensity and damage degree of flood disaster， and accurate assessment of flood disaster is the basis of targeted flood control and disaster reduction work. In order to fully characterize the scope and depth of flood disasters， this paper， based on the main disaster bearing bodies of flood disasters， screened flood disaster assessment indicators from five main impact levels of flood disasters， namely population affected by the disaster， crop affected， house damage， damage to water conservancy and flood control facilities and economic losses， and constructed the national and regional annual flood disaster assessment index system at the target layer， factor layer and indicator layer. The annual flood disaster situation was evaluated based on the annual flood disaster grade and the annual flood disaster comprehensive loss degree. The CRITIC-weighted grey correlation analysis model was constructed by coupling CRITIC weight method and grey correlation analysis model to evaluate the annual flood disaster grade. The disaster index method was used to evaluate the annual comprehensive loss degree of flood disasters. Based on the advantage of ArcGIS to visually present spatial data， the annual flood disaster grade and comprehensive loss degree of each region were presented in the form of zoning maps. Based on the above methods， the annual flood disaster assessment was carried out in the whole country and various regions from 2006 to 2021. The results showed that： Among the national annual flood disaster assessment results， 2010 witnessed flood disasters at extreme level， and 2013 and 2016 witnessed flood disasters at major level； In the annual flood disaster assessment results of each region， Hunan Province in 2006 and 2017， Henan Province in 2021 annual flood disaster level reached extreme level； The provinces with heavy floods and high frequency of floods are Sichuan， Hunan， Hubei， Jiangxi， Guangdong and Hainan. The results of annual flood disaster assessment based on CRITIC-weighted grey correlation analysis model and the disaster disaster index method can be used as a basis for regional flood control and disaster reduction work.

It is of great significance for the sustainable development of the Yangtze River Economic Belt to correctly understand and clarify the coordinated development relationship among water resources， economic society and ecological environment. Based on the actual situation of the development of the Yangtze River Economic Belt， and considering the internal and external factors of the development of water resources， economic society and ecological environment， a 30-item evaluation index system of water resources， economic society and ecological environment was constructed. At the same time， based on the comprehensive evaluation index model， coupling coordination degree model and obstacle degree model， the spatial and temporal evolution of the system comprehensive development level and coupling coordination degree in 11 provinces （cities） along the Yangtze River Economic Belt from 2008 to 2021 and the obstacle factors affecting the system coupling coordination degree were analyzed. The results show that the comprehensive development level of the three systems of water resources， economic society and ecological environment in the Yangtze River Economic Belt is on the rise， but the inter-provincial differences are obvious， especially the differences of the social and economic subsystems. The three systems as a whole always maintain a high level of coupling state， and the interaction between subsystems is more and more obvious. The coupling coordination degree of the system is increasing year by year， and it has undergone a transformation from near imbalance decline to primary coupling coordination. The development rhythm of the coupling coordination degree of various provinces （cities） is different in space， which is manifested as the distribution characteristics of “downstream > midstream > upstream”. According to the analysis of obstacle factors， it can be seen that urban water conservation and industrial pollution control investment are important factors affecting the coupling and coordinated development of the system. In the future， the Yangtze River Economic Belt can make more efforts in water resources management and ecological environment governance， while paying attention to economic and social issues， so as to achieve high-quality development of the Yangtze River Economic Belt.

In the southeastern coastal areas of China， complex flood disaster factors and compounded terrain features often lead to poor flood discharge in watersheds， resulting in flood disasters. Therefore， it is essential to establish a flood simulation model suitable for the characteristics of this watershed and formulate effective flood control and disaster reduction measures through flood mitigation analysis. By utilizing watershed digital elevation data， river network data， land use data， etc.， a hydrodynamic-hydraulic coupled model simulating the flood process in a coastal hilly-plain composite watershed is established to explore methods for reducing flood risk based on engineering scheduling. The Datian Port watershed in Linhai City， Zhejiang Province， is selected as the study area， taking into account watershed characteristics such as hilly convergence， reservoir discharge， tidal fluctuations， initial river channel water levels， and floodgate discharge. Model boundary conditions are designed to simulate the flood evolution process and inundation situation in the study area under different design floods and engineering scheduling influences. The results indicate that the established model can effectively simulate the flood evolution process in the composite watershed of hills and plains. For key flood-prone areas， adjusting the initial water level in the river and controlling flood tide gates in the watershed effectively alleviated flood inundation in the downstream main urban area and Ling Lake scenic area of Datian Port. The downstream engineering scheduling delayed the relief effect on flood inundation in the northeast area of the Datian Port watershed， bordering the hills. Scenario simulation results provide data support for the pre-assessment， prediction， early warning， and contingency planning of flood disasters in the study area， laying a foundation for the further advancement of urban flood control and plain drainage projects and offering solutions for flood disasters caused by multiple disaster factors in coastal hilly-plain composite watersheds.

In order to further study the spatial balance of water resources in Henan Province， aiming at the fuzziness and uncertainty of the spatial balance of water resources， this study established a quantitative index system of spatial balance discrimination criteria， calculated the regional water resource load index， matching coefficient of soil and water resources and water use efficiency， and introduced the Gini coefficient to describe the degree of spatial balance of water resources. A robust water resources spatial equilibrium evaluation model was constructed to evaluate the water resources spatial equilibrium in Henan province through robust grade calculation， correlation number method to determine the uncertainty transformation grade and subtraction set pair potential method to calculate the spatial equilibrium trend. The results show that the load index of water resources in Henan Province in 2020 was 38.996， which was a large load. The load in the north was greater than that in the middle， and the middle was greater than that in the south， and the development potential in the south was the best， and the distribution was extremely unbalanced. The matching coefficient of water and soil resources was 0.544， which varied greatly among different cities. The water use efficiency was relatively balanced. In 2020， the spatial equilibrium distribution of water resources in Henan Province was uneven， and the equilibrium level was Ⅳ. Among the 18 cities， the distribution of equilibrium level was different， and the south was better than the north. Among them， the spatial equilibrium of water resources in Anyang City was the worst， with a level of Ⅴ， which was completely unbalanced； The spatial equilibrium of water resources of Zhengzhou， Luoyang， Hebi and Xuchang were in level IV， which was relatively unbalanced. The rest of the cities were in level III and below， and the balance condition were better. Large regional water resources load， low matching degree of water and soil resources， and large gap of indicators among counties in the region were important reasons for the spatial imbalance of water resources. The overall spatial balance of water resources in Henan Province showed a small positive evolution trend， and the spatial balance of water resources in 11 cities such as Kaifeng showed a positive evolution trend， while the other 7 cities showed a negative evolution trend to varying degrees.

Accurate and real-time monthly runoff forecasting is essential for optimizing water resource management and flood and drought mitigation in river basins. Influenced by both climate change and human activities， the non-stationary characteristics of basin runoff processes are pronounced， challenging the stationary assumptions of traditional forecasting methods. This paper focuses on the dynamically variable dependencies among hydrological variables under non-stationary conditions， developing a novel simulation method that integrates Non-stationary Graphical Modeling and Bayesian Networks （NGM-BNs）. This method is applied to monthly runoff forecasting in the Kashgar River Basin in Xinjiang. The process is as follows： initially， the research variable sequence is transformed through reliable data conversion methods to meet the normal distribution assumption， significantly enhancing the predictive accuracy of the Bayesian network model. Subsequently， the Bayesian network structure and parameters are dynamically adjusted during the forecasting phase to realize monthly runoff forecast simulation under non-stationary conditions. Based on five performance metrics—normalized root mean square error， Kling-Gupta efficiency coefficient， Nash efficiency coefficient， index of agreement， and coefficient of determination—NGM-BNs demonstrated superior forecasting accuracy compared to four common data-driven models， including non-stationary and stationary conditions of Support Vector Regression （SVR） and Adaptive Neuro-Fuzzy Inference System （ANFIS） models. The non-stationary Bayesian network model's ability to incorporate time-varying characteristics of variables enhances its capability to capture extreme flow events. This study can provide reliable technical support and theoretical assurance for flood and disaster reduction in river basins under a changing climate.

In order to effectively improve the calculation accuracy of reference crop evapotranspiration （ET ₀） in the Jialing River basin when meteorological data is lacking， daily meteorological data in the past 58 years （1960-2017） were collected from twenty meteorological stations in Jialing River basin and it′s vicinity， 16 ET ₀ calculation models were built based on Long Short-Term Memory （LSTM） according to different combinations of meteorological elements. The calculation accuracy of these models was compared with the Hargreaves-Samani， Makkink， and Irmark-Allen models to investigate the applicability of LSTM models in the Jialing River basin. The results showed that： ① LSTM models could accurately capture the complex nonlinear relationship between the input parameters and ET ₀. The LSTM2 model， which was based on the maximum temperature（T _max）， the minimum temperature（T _min）， and the extraterrestrial radiation（R _a）， achieved a high calculation accuracy （on average， MAPE=14.6%， RMSE =0.476 mm/d， NSE=0.891， R ² = 0.903）， meeting the requirements for practical applications. The calculation accuracy of the model increased with the number of input meteorological elements. ② If R _a is added to the input parameters， it is a significant improvement in model accuracy（on average， MAPE is reduced by 17.3%， RMSE is reduced by 11.1%， NSE is increased by 0.779% ， and R ² is increased by 0.715% ）. ③ The LSTM12 model based on T _max， T _min， R _a， and sunshine time（n） is the most suitable ET ₀ calculation model when there is a lack of meteorological data in the Jialing River Basin. ④ Under the same input parameters， the calculation accuracy of the LSTM model was better than that of the Hargreaves-Samani， Makkink， and Irmark-Allen models. ⑤ The LSTM model demonstrated strong portability in the Jialing River basin. When LSTM models established at different meteorological stations were transplanted to each other， they still maintained high accuracy （MAPE<7.42%， RMSE<0.242 mm/d， NSE> 0.972， R ²>0.980）. Therefore， the ET ₀ model based on Long Short Term Memory Network （LSTM） has good applicability and can be used as a recommended model for calculating ET ₀ in the Jialing River basin when meteorological data is lacking.

With the economic and social development of the Han River basin， the pressure on the water environment and water ecology has increased， and the implementation of the water diversion project from the Yangtze river to the Han River may lead to further changes in the quality and quantity of water in the Han River. Therefore， it is of great significance to carry out simulation analysis and prediction of water quality and water quantity in the middle and lower reaches of the Han River before and after the water diversion project， in order to control the pollution of water bodies in the basin. In this paper， we predicted the water quantity and quality response of Huangjiagang-Wangfuzhou section after the diversion of water by using the segmented Muskingum method and one-dimensional and two-dimensional water quality models. The results show that： ① After the river diversion project adopts the year-round uninterrupted water diversion method to divert water， the flow of the Huangjiagang-Wangfuzhou river section increases， and the increase of flow in the summer flood is higher than that in the fall flood， and the increase of flow in the Wangfuzhou section is slightly higher than that in the Shenwan section； ② Before and after the water transfer， the average monthly total phosphorus concentration in Shenwan section reached the water quality standard of Class II， and the average monthly total nitrogen concentration was within the standard of Class IV-V. The growth rate of various water quality indicators under Scenario 2 was 2-3 times that of Scenario 1. Compared with before the water transfer， the total phosphorus concentration in Scenario 1 increased by a maximum of 4.68%， and the total phosphorus concentration in Scenario 2 increased by a maximum of 13.45%. This was followed by total nitrogen， with a maximum increase of 1.15% for scenario 1 and 3.44% for scenario 2； ③ Monthly total phosphorus concentration in the flood season at Wangfuzhou section before and after the water transfer reached the water quality standard of Class II， and the total phosphorus concentration increased in dry water years after the water diversion while the concentration decreased slightly in abundant water years. Overall， the variation of water quality in dry water years is greater than that in abundant water years， and the variation of each water quality indicator is not much different in the two scenarios.

In order to explore whether the Tesla valve fishway and the two vertical slot fishways can meet the fish migration conditions， based on the method of Fluent using the standard RNG k-ε turbulence model and the VOF multiphase flow method to capture the free water surface， the three-dimensional turbulence flow field of the three fishways was simulated， and the influence of the hydraulic characteristics of the three fishways on the migration of the four major fish was mainly studied by using the same boundary conditions. The analysis shows that the main stream of the three fish passages is clear， the flow pattern is obvious， and the main flow pattern is less and less obvious from the bottom to the upper layer， and the flow velocity shows a decreasing trend. The average flow velocities of the double-sided vertical slot fishway， the opposite-sided vertical slot fishway and the Tesla valve fishway were 0.49， 0.45 and 0.69 m/s， respectively， the average proportion of the return zone was 0.67， 0.71 and 0.69， respectively， and the maximum flow velocity was 1.24， 1.49 and 1.54 m/s， respectively. The maximum cross-sectional flow velocities of the double-sided vertical slot fishway， the opposite-sided vertical slot fishway and the Tesla valve fishway were 1.09， 1.38 and 1.54 m/s， respectively， and the average flow velocity of the cross-section was 0.75， 0.57 and 0.85 m/s. The maximum turbulent kinetic energy of 0.054 m²/s² of the double-sided vertical slot fishway appeared behind the upper water separator， and the turbulent kinetic energy in most of the other areas was less than 0.05 m²/s². The maximum turbulent kinetic energy of 0.072 m²/s² of the opposite-sided vertical slot fishway occurs at the outlet of the vertical seam of the upper water body， and the turbulent kinetic energy of most of the other areas is less than 0.05 m²/s². The maximum turbulent kinetic energy of 0.221 m²/s² of the Tesla valve fishway occurs in the unit loop of the upper water body， and the turbulent kinetic energy of most areas of the main channel is less than 0.05 m²/s². The analysis shows that the flow velocity and flow regime of the three fishways meet the fish migration conditions， and the turbulent kinetic energy of the fish migration route areas of the three fishways meets the fish migration conditions.The research results of this paper can provide ideas for fishway designs in the future.

In order to study the distribution law of water flow velocity between vegetation in flexible submerged vegetation zone， flexible plastic grass was selected for flume experiments， and the flow velocity between vegetation along the water flow and vertical water flow direction was analyzed by setting up different flow rates and submergence degrees under two arrangements of rectangle and plum blossom shape. The results showed that the longitudinal vertical flow velocity curves between vegetation along different directions were quite different； the increase of flow conditions such as flow rate and inundation degree and the staggering of the arrangement would increase the inhibition effect of vegetation on water flow， but the effect of flow conditions on the flow velocity in the canopy area of vegetation was greater than that of the arrangement； under the two arrangements， the mean flow velocity of the vertical flow line decreased with the increase of flow rate and increased with the increase of the inundation degree； the flow rate of the plum blossom shaped arrangement is smaller than that of the rectangle， and the change of flow rate is also small when the water flow condition changes， and the effect of blocking the water flow， flood control and peak shifting is better in the actual project.

Accurate water quality prediction and identification of key factors are important foundations for water environment control and water resource protection in river basins. Considering the diversity of surface water quality evaluation indicators and the nonlinear and non-stationary characteristics of raw data， an improved ensemble empirical mode decomposition （EEMD） and grey wolf optimization （GWO） integrated data prediction model is proposed based on the traditional decompose-forecast-integrate time series prediction framework. This model utilizes the ensemble empirical mode decomposition method to decompose the data into different frequency components. Then， Elman neural network， long short-term memory neural network （LSTM）， and support vector regression （SVR） are employed as base learners for individual predictions. Subsequently， a grey wolf dynamic optimization integration strategy is applied to integrate the prediction results. Finally， the model's effectiveness is evaluated using data from a water quality section in the lower reaches of the Yangtze River， and compared with single prediction models and average integration strategies. The research results show that the proposed model performs excellently in error evaluation metrics and DM test. It outperforms other models， especially in the prediction of dissolved oxygen. Compared to the average integration strategy prediction model， the grey wolf optimization integration model reduces the mean absolute error （MAE）， root mean square error （RMSE）， and Theil inequality coefficient （TIC） by 16.29%， 13.17%， and 13.24% respectively. The model achieves a prediction accuracy of 98.6% for final water quality grades， indicating its capability to accurately predict water quality levels and identify key influencing factors， thus providing a scientific basis for water environment pollution control.

Rock weirs are common low-head hydraulic structures in small and medium-sized rivers， and the biofilms formed by riverine microorganisms on their surfaces affect the river environment. Current studies mainly focus on the microbial characteristics in biofilm coated on the river bed stones， but less attention has been paid to biofilms on the surface of rock deposits such as rock weirs. Based on high-throughput sequencing technology， the microbial community composition in biofilms coated on a rock weir in a natural small and medium-sized river is investigated. Also， the effect of different aquatic environmental factors around this structure on the microbial community is studied through correlation analyses. The results show that： ① The hydrodynamic conditions vary in different areas around the rock weir， while the water physicochemical properties around the weir are similar； ② The diversity of microbial communities in biofilms on different areas of the weir surface is different， with the lowest being at the weir crest， followed by the upstream weir surface， and the highest being at the downstream weir surface； ③ The composition of microbial communities in biofilms on different areas of the weir surface is similar， with the dominant phylum being Proteobacteria， but the dominant genera in biofilms on the weir crest are different from those in other areas. ④ Various aquatic environment factors around the weir affect the community structure of microorganisms in the biofilm on weir surface， with the effects of flow velocity， water depth and dissolved oxygen reaching the level of significance. The results of this study reveal the microbial community characteristics of biofilms on the surface of rock weirs in natural small and medium-sized rivers， which can provide a certain basis for understanding the ecological benefits of rock weirs.

The willingness and behaviour of farmers to engage in rural sewage treatment efforts are key to the effectiveness of rural sewage treatment work. In order to promote rural sewage treatment initiatives from the level of farmers， this paper is based on the theory of Knowledge， Attitude， Practice， beginning with the two primary factors of farmers’ cognition and attitude， combined with the basic characteristics of farmers and sense of responsibility in a total of four dimensions， a binary Logit model was constructed to examine farmers' willingness to participate in rural sewage treatment. This model was developed using survey data collected from 438 farmers in Jingdezhen， Jiangxi Province， an area characterized by higher economic development. Subsequently， the main influencing factors of satisfaction， willingness to participate， and willingness to pay were analyzed. Combined with the satisfaction scale， the shortcomings constraining the satisfaction of rural sewage treatment work in this type of area were identified， and the main measures and directions for improving rural sewage treatment work were pointed out. The results of the study show that： the satisfaction of farmers in the region is significantly affected by gender and cognitive factors； the willingness to participate is significantly and positively correlated with farmers' cognitive factors， attitudinal factors， and sense of responsibility； and the willingness to pay is significantly affected by age， gender， and attitudinal factors， which is significantly different from the factors influencing the economically developed and underdeveloped regions. The water quality of water bodies around rural residents and the construction and use of sewage treatment facilities are the main shortcomings affecting the satisfaction of the treatment work. Upgrading the level of economic development in the region， strengthening the sense of responsibility for treatment， focusing on optimising the construction and operation of rural sewage treatment facilities， and carrying out environmental protection publicity and education for characteristic groups such as women and young people are the main directions of improvement for comprehensively increasing the willingness of farmers to treat rural sewage and assisting in the treatment of rural sewage. The research results can provide a reference for the effective promotion of rural sewage treatment in China from the perspective of environmental behaviour.

The water environment management effectiveness of Jiangxi Province under the river chief system was investigated in this paper using the super-efficiency SBM model and Tobit model to evaluate and analyze the water environment management efficiency and its influencing factors in 11 prefecture-level cities in Jiangxi Province from 2010 to 2021. The results indicate that the water environment management efficiency in Jiangxi Province decreased from 0.948 in 2010 to 0.792 in 2014， and then increased to 0.978 in 2021， showing a trend of initial decline followed by a rise. Additionally， the water environment management efficiency in Jiangxi Province displays spatial variation， with northern Jiangxi outperforming central Jiangxi， and central Jiangxi outperforming southern Jiangxi. Since the implementation of the river chief system （2016-2021）， the water environment management efficiency in Jiangxi Province has increased by 9.4%. It was also found that the economic level and technological innovation have positive correlations with the water environment management efficiency in Jiangxi Province， while industrial structure， resource endowment， and spatial agglomeration have negative correlations. The key to improving water environment management efficiency in various parts of Jiangxi Province lies in enhancing economic development levels and optimizing industrial structures. The research findings can provide scientific support for improving water environment management efficiency， implementing the river chief system， and creating an ecological civilization model in Jiangxi Province.

This study employs ground hyperspectral remote sensing to analyze the water quality parameters， specifically total nitrogen （TN） and total phosphorus （TP）， in the midstream of the Xiangxi River. Using 160 data samples， inversion models were developed through six methods： single-band analysis， first-order differential band analysis， band ratio analysis， dual-wavelength difference index， normalized difference index， and partial least squares （PLS） regression. The results show that single-band and first-order differential analyses were ineffective for TP and TN. Band ratio analysis improved TN inversion accuracy， achieving an R ² of 0.367 4 with second-order regression analysis. The highest R ² of 0.401 4 for TP was obtained using third-order regression of the dual-wavelength difference index. PLS regression showed an outstanding performance in TN inversion， with an R ² of 0.39， RMSEP of 0.501， and ARE of 40.278%， showing a certain prediction accuracy. These findings support the potential of hyperspectral remote sensing for predicting the long-term trend of TN and TP in the middle reaches of Xiangxi River， though further optimization of models is needed due to current limitations in data and water body types.

The evaluation on the effectiveness of post-resettlement support（PRS） policies for reservoir migrants is beneficial to comprehensive understanding of the implementation of policies， identification of problems in a timely manner， and proposal of corrective measures. An evaluation method of PRS effect is proposed based on set pair analysis and variable fuzzy set to solve the problems of strong subjectivity and possible distortion of evaluation results in most of the current evaluation methods of PRS effect. Firstly， an evaluation index system of PRS effect is constructed based on the literature and the opinions of experts. Secondly， the initial clustering center is calculated by using the potential energy function of the data field， and then the indexes are classified by using the K-means clustering method. Then， the entropy weight method is used to determine the index weight， and the set pair analysis and variable fuzzy set are coupled to evaluate the effectiveness of PRS. Finally， a case study is conducted on the implementation of PRS policies for large and medium-sized reservoir resettlement in Guangdong Province by using the proposed evaluation method. The results indicate that this method can objectively reflect the effectiveness of PRS for local immigrants， and the evaluation results are reasonable and credible. The research results can provide reference for scientific decision-making by relevant government departments and implementing agencies.

Research on hazard risk plays an important role in the smooth implementation progress of engineering projects. Taking temporary roads for the water conservancy and hydropower engineering in Sichuan Province as research objects，and earthquake as the hazard factor， this paper analyzed the temporary roads from two aspects： geological environment and earthquake hazard. We founded a mathematical model for risk assessment of temporary roads affected by earthquakes， by using fuzzy set theory and judgment matrix methods. We analysed the possibility of roads subjected to earthquake damage in 18 912 grid cells in Sichuan Province. The conclusion shows that temporary roads in Sichuan are more likely to suffer moderate damage from earthquakes， among which Jiuzhaigou and Wenchuan County in Aba Prefecture， and Qingchuan County in Mianyang City are likely to suffer the most serious damage.

Considering the seasonal variations of hydroelectric prices and probabilities of electricity price fluctuations in the future， this study established a joint optimal operation model of cascade hydroelectric plants for maximizing hydropower generation benefits， which was solved by the Dynamic Programming-Progressive Optimality Algorithm （DP-POA）. The study investigated hydropower generation benefits under three electricity price scenarios， including the average electricity price and electricity price increase during the non-flood and flood seasons， and extracted joint operation strategies of cascade hydroelectric plants. The six cascade hydroelectric plants in the middle reaches of the Jinsha River， including Liyuan， Ahai， Jinanqiao， Longkaikou， Ludila and Guanyinyan in the middle reaches of the Jinsha River were selected as the research objects. The results showed that： ① The on-grid electricity prices of the cascade hydropower stations in the middle reaches of the Jinsha River during the non-flood season were significantly higher than those during the flood season， but the power generation volume and benefits of the flood season were greater than those of the non-flood season； ② Joint optimal operation could increase hydropower generation and hydroelectric benefits. Under different electricity price scenarios， the maximum increase can be 7.33×10⁸ kWh and 2.01×10⁸ yuan， respectively； ③ Compared to the conventional operation processes， the water levels of cascade hydroelectric plants mainly declined in advance in May and June and were delayed to be fully impounded in August and September. The research results can provide references and technical supports for joint optimal operation of cascade hydroelectric plants in the middle reaches of the Jinsha River.

In order to study the influence of blade bionic surface on the performance of hydraulic turbine， based on the drag reduction property of shark skin surface structure， three different sizes of V-grooves are designed， which are arranged in the front one-third of the inlet section of the turbine working surface. Numerical simulation and experimental verification of the hydraulic turbine are carried out using the RNG k-ε turbulence model to study the external characteristics of the hydraulic turbine， the shear stress of blade wall， and the turbine internal flow characteristics under different flow rates. The results show that the hydraulic efficiency of the three types of V-groove blade hydraulic turbine is improved compared with that of the smooth-surface blade， and the V-groove can reduce the velocity gradient of the fluid near the wall of the blade， so that the frictional resistance between the fluid and the wall is reduced， the turbulent kinetic energy in the impeller is reduced， and the energy dissipation is reduced. At the 1.125Q _BEP working condition， the V-groove hydraulic turbine with s=1.5 mm has the largest increase in hydraulic efficiency of 1.8% and the largest reduction in shear stress on the V-groove blade wall of 43.97%.

This article focuses on the influence of blade inlet at different positions on the hydraulic performance of centrifugal pumps. NM150-250/30 centrifugal pumps are taken as the research object， and a combination of experimental testing and CFD numerical simulation is used to analyze and explore the external characteristics and internal flow field of centrifugal pumps. SOLIDWORKS software is used to establish three different impeller models， TurboGrid is used for Hexahedron mesh generation， and CFX19.2 is used for steady numerical simulation. The research found that as the blade inlet of the centrifugal pump extends forward towards the impeller inlet， the head and efficiency values of the centrifugal pump also increase under the design conditions. Moreover， under low flow conditions， the flow head curve of the centrifugal pump shows a saddle zone similar to that of a mixed flow pump， and the pump efficiency rapidly decreases and the high efficiency zone is narrow. As the position of the blade inlet continues to extend forward， the inlet reflux generated by the flow under low flow conditions continues to increase， the centrifugal pump saddle zone expands， and the flow state deteriorates.

Based on the non-stationary and non-linear characteristics of the vibration signals of hydroelectric units， we propose a method that combines second decomposition， Simple Recurrent Units （SRU）， and Attention Mechanism. Firstly， we use ICEEMDAN and VMD methods to perform second decomposition on the vibration signals， decomposing the signals into Intrinsic Mode Functions （IMFs）. Subsequently， we introduce a deep learning model based on SRU， and the extracted IMF signals are input to the SRU for learning to obtain a fault recognizer for hydroelectric units. To further enhance the model's performance， the Attention Mechanism is incorporated into the SRU to allow the model to dynamically focus on important information from different IMFs. By combining the fault recognizer with real-time vibration signal features， the operational state of hydroelectric units can be identified as normal， warning， or a specific fault type. Finally， to validate the effectiveness of this method， comparative experiments are conducted using actual data samples from power plant units， confirming the feasibility and superiority of the proposed method in extracting signal features.

Sediment water can cause serious wear and damage to pump stations along the Yellow River. The vortices in the pump sump will exacerbate pump wear and greatly affect the operational lifespan of the pumps. In order to investigate vortex control technology in pump sump under sediment water condition， a vortex-suppressing intake bell mouth with wavy leading-edge hydrofoils inspired by bionics is developed. The impact of the bell mouth with wavy leading-edge hydrofoils on vortices in the pump sump is analyzed through model experiments under both clear water and sediment water conditions. The results indicate that， regardless of clear water or sediment water condition， the bell mouth with wavy leading-edge hydrofoils effectively suppresses submerged vortex， reduces the frequency of their occurrence， and decreases the pre-swirl intensity within the inlet pipe. It improves the inlet flow patterns inside the pump， and then prevents further exacerbation of erosive wear.

This paper reviews the technical background and development progress of digital twin technology， and points out that digital irrigation district is a fundamental part for the digital twin irrigation district establishment. Modernized digital irrigation district is an important stage of development to promote the construction of digital twin irrigation district. Based on a functional understanding of the mathematical model and within the framework of digital twin irrigation district， it is firstly proposed to divide the mathematical model into three levels， namely basic platform model， targeted application model and friendly interaction model. Based on the definition of digital twin irrigation district， it also analyzes that the digital twin model has the essential features with real-time dynamics and closed-loop feedback. There exsists a process of synchronous simulation， virtual-real interaction and iterative optimization between physical irrigation district and twin irrigation district. They influence and promote each other throughout the life cycle of the irrigation district. The twin irrigation district not only changes in real-time with the change of physical irrigation district， but also the analysis and decisions based on the twin irrigation district will feed back to the physical irrigation district in real-time which results the response of the physical irrigation district. Therefore， in practice， problems should be identified based on the real needs of physical irrigation modernization， and the principles of real need， water-saving efficiency and sustainability should be followed. Digital twin physical object of irrigation district should be accurately selected and focused， mathematical models need to be optimized and innovated. Key advanced technologies and properly major application should be developed and practiced. Network security and data safety should be strengthened. It is expected to establish a digital twin irrigation district more orderly， accurately and efficiently.

This paper intends to explore the mechanism of efficient and accurate extraction of soil salinization information in Hetao Irrigation District by remote sensing images， and invert the salinity of Hetao Irrigation District by constructing a feature model to provide data reference for soil salinization control in Hetao area. Based on Landsat 7 ETM+ and Sentinel-2 remote sensing image data， spectral parameters were extracted according to different bands ： salinity index （SI）， normalized difference vegetation index （NDVI）， surface albedo index （Albedo） and modified soil-adjusted vegetation index （ MSAVI ）. Combined with the above spectral parameters， a remote sensing salinity detection index （ SDI ） model was constructed to extract and analyze the salinized soil information in Hetao Irrigation District， and the accuracy of the model was verified by combining the measured data and constructing the confusion matrix. The model with higher accuracy verification results was selected to analyze the degree of soil salinization in Hetao Irrigation District.After evaluating the accuracy of the model through the confusion matrix， the SI-Albedo feature space model SDI2 model has the highest overall accuracy， reaching 86.79%， and the Kappa coefficient is 0.82. The overall classification accuracy of SDI1， SDI3 and SDI4 with the confusion matrix is 79.25%、45.28% and 69.81% ， respectively.The results show that the SI-Albedo feature space model SDI2 is more suitable for the extraction and inversion of salt information in Hetao Irrigation District.Among the four types of remote sensing salt monitoring index models， the SI-Albedo feature space model SDI2 has a strong reference value for salt inversion in the study area.

The high spatial variability of soil salinity in arid and semi-arid areas severely affects crop cultivation. Geostatistics is an effective method to characterize the spatial distribution of soil salinity， and sequential Gaussian simulation provides higher reliability in assessing the impact of high spatial variability of soil salinity on crop salt stress. This study selects the mid-lower reaches of the Yanqi Basin in Xinjiang as the research area. The soil salt data in 2005 and 2019 were used to characterize the spatial distribution patterns of soil salt by geostatistical methods. The salt tolerance value of crop seedlings was used as the threshold， and the probability of soil salinity stress on crops exceeding this threshold was calculated， providing a reference for the rational use of cultivated land resources and crop planting planning in the study area. The results shows that the soil salinity content in 2019 was significantly lower compared to 2005， with a decrease of 36%， 48%， and 50% from the surface，middle and deeper layers， respectively.The spatial variability of surface soil salinity increased， with the coefficient of variation rising from 98% to 108%. In the horizontal direction， soil salinity showed a trend of decreasing as it approaches the Kaidu River； in the vertical direction， most of them exhibited a surface-aggregated pattern. The statistical results of sequential Gaussian simulation better reflect the spatial variability of soil salinity in the Yanqi Basin， with a difference in the variogram coefficient within 5% of the original data， overcoming the problem of high-value underestimation of ordinary kriging. Combined with crop threshold values， the probability of crop salinity stress can be quantitatively evaluated. Based on the probability maps of crops exceeding the threshold， the probability of salt stress for tomato， corn， wheat， and cotton planting in the eastern part of the Twenty-two Regiment and the southwestern corner of Forty-Li Chengzi Town exceeds 60%， accounting for 4.5%， 2.5%， 1%， and 0.7% of the study area， respectively. For areas with soil salinity greater than 10 g/kg， increasing irrigation water volume and spring leaching can reduce the probability of crops experiencing soil salinity stress.

Resistivity is an important characterization index of physical and mechanical properties of concrete. Under the condition of low temperature， the tensile strength， compressive strength and elastic modulus of concrete are obviously different from those in normal temperature environment. Monitoring the resistivity change of frozen concrete under load is of great significance for early warning and evaluation of the working state of concrete structure. In this paper， the saturated water content concrete samples were selected for uniaxial compression test at five temperatures of 28， -5， -10， -15 and -20 ℃， and the relative resistivity changes of the samples were monitored simultaneously until the samples were destroyed. According to the deformation and failure process of concrete， it is divided into three stages ： compaction stage， elastic deformation stage and crack expansion stage. The results show that ： ① Compared with the condition of 28 ℃， the low temperature environment significantly delays the time for the concrete sample to reach the ultimate load after cracking. In the later stage of the load-displacement curve at the temperature of -15 and -20 ℃， the curve in the crack extension stage becomes slower， and the displacement of the loading point increases when the specimen breaks. Other conditions being the same， the lower the temperature， the longer the final failure time of the specimen. ②The low temperature environment improves the peak strength and elastic modulus of saturated water content concrete samples. When the temperature decreases from-5 to -15 ℃， the peak strength and elastic modulus of the sample increase gradually. When the temperature is -15 ℃， the peak strength and elastic modulus reach the peak value， and the increase of elastic modulus is higher than that of peak strength. ③ Under the condition of uniaxial compression， the relative resistivity changes of saturated water content concrete samples at different stages are different. In the pore compaction stage， the relative resistivity gradually increases with the decrease of the test ambient temperature. In the elastic deformation stage， the relative resistivity curve gradually changes from convex to concave， and the difference gradually decreases. In the stage of crack expansion， the relative resistivity increases suddenly until the concrete specimen is destroyed by penetrating cracks. Therefore， relative resistivity can be used as an early warning method for the critical failure of saturated water content concrete structures under low temperature conditions.

In order to study the method of determining the control conditions of energy dissipation and anti-scouring of sluice， the actual project of Tongcheng Sluice is taken as an example. Based on the optimization model， this paper adopted numerical simulation method to select 5 gate openings respectively in the design condition and the check condition of energy dissipation and to calculate the energy dissipation and anti-impact.The maximum single width energy passing through the gate is determined by analysis to find the most unfavorable working condition of the sluice during operation. After the model is optimized， the calculation length of the upstream section of the rear sluice was selected as 90m， the downstream section of the anti-scour slot was 40 m， the mesh division form was the local encrypted mesh based on coarse mesh and the turbulence model was RNG k-ε. Based on this model， the final calculation and analysis shows that， when the sluice opening was 4.0 m under the energy dissipation design condition， the processed energy of the single width of the sluice reached the maximum. Under this condition， the upstream water level was 10.1 m and the downstream water level was 5.6 m， which was the control condition of energy dissipation and anti-scouring of the sluice. The research content of this paper broke the traditional idea of taking the sluice discharge condition as the most unfavorable condition， which can guarantee the safe operation of the sluice. It had good engineering application value and can provide reference for determining the design conditions of energy dissipation and anti-scouring in sluice engineering.

To improve the accuracy of reservoir inundation calculation in plains with complex geological structures， a new method for calculating underground water inundation in inter-river blocks is proposed. The main concept of this method is to focus on the development of the Groundwater Connected Domain Calculation （GCDC） algorithm， which assumes that underground water inundation can only occur in binary geological structures where the upper layer is a weakly permeable layer and the lower layer is a moderately permeable layer. The GCDC method utilizes drilling data and critically safe ultra-high-definition three-dimensional geological models， integrates Digital Elevation Model （DEM） data of surface land use types， and constructs topological relationships for conducting connected searches of underground water inundation. Taking the river land blocks between the middle and north branches of the Gan River Weilu Project as an example， the application and effectiveness of this method are verified. The results indicate that the GCDC method can simulate the calculation and prediction of reservoir inundation in plains， and can characterize underground water inundation under a range of conditions with different water levels. Additionally， the GCDC method can also classify the severity of underground water inundation. Overall， the GCDC method is a useful tool for assessing the impact of underground water inundation， as it has good reliability in terms of permeation theory and operability in data input.

The existing hydraulic tunnel surrounding rock classification method is still mainly empirical， which is easy to cause deviation of the surrounding rock classification results and lead to irrational tunnel support design， and even surrounding rock destabilization in the excavation process. Relying on the Dashanling diversion tunnel project of Quanmutang Reservoir， this paper adopts the numerical image technology to modify the HC method， which can realize the fine surrounding rock classification of hydraulic tunnels and provide a basis for reasonable tunnel support design. To this end， firstly， the grading method of HC method for hydraulic tunnel surrounding rock classification is clarified by adopting the point load test for rock strength， and the grading method of determining the degree of integrity of the rock body， the state of structural surface， and the yield of structural surface by adopting the numerical image technology. Secondly， the practical application of the Jiulongling Tunnel No.2 branch shows that the uniaxial compressive strength of the rock body taken is 24.22 MPa， the angle of the structural surface strike to the tunnel axis is 32.5 The uniaxial compressive strength of the rock body taken is 24.22 MPa， the angle between the structural plane and the axis of the hole is 32.5°， the inclination of the structural plane is 40.1°， and the filler of the structural plane mainly consists of rock debris， which is in the state of microtension， with a rough undulation and the number of volumetric joints of the rock body is 3 ≤ Jv ≤ 10. Finally， with reference to the “Code for Hydropower Engineering Geological Investigation”， and combining with the scoring guideline of the HC method， the total scoring of surrounding rock at the branch hole No.2 of Jiulongling of Quanmutang， ZG23 + 717.5， assessed to be 29 points， and the grade of the surrounding rock is class Ⅳ. The method has the advantages of convenient image acquisition， concise calculation process， and accurate analysis results， etc. It can provide important decision-making support for the design of excavation and support of hydraulic tunnels， and has significant engineering practical value and wide application prospects.

Numerical simulations were carried out to solve the problems of poor advanced small conduit support and serious over-excavation and over-consumption in the drastically sandy dolomite tunnel of the Dianzhong water diversion project. The orthogonal working conditions designed with the length of advanced small conduit， annular spacing， and cyclical footage as factors were calculated. According to the numerical simulation results， a comprehensive evaluation of the indicators of surrounding rock deformation， structural stress and construction cost was carried out based on the subjective and objective combination assignment. The results show that increasing the length of advanced small conduit and reducing the cyclical footage can effectively control the settlement of the vault and the convergence of the tunnel sidewalls， respectively； the structural force is affected by the cyclical footage to the greatest extent， and the length of small conduit and cyclical footage have a slightly greater impact on the construction cost. Combined with the comprehensive evaluation and field test results， under the condition of strongly sandy dolomite stratum of the relying project， the parameters of advanced small conduit support should be 3 m in length， 0.2 m in annular spacing， 0.6 m in steel frame spacing， and 1.8 m in cyclical footage， and the surrounding rock stability is good under the monitoring of this parameter combination， and the phenomenon of dropping blocks is reduced， and the effect of over-excavation control is enhanced.

Located in the northwestern region of Yunnan Province within the Lancang River Basin， the HD Reservoir area features a high-mountain canyon terrain with complex engineering geological conditions， hosting numerous landslides that pose significant monitoring challenges. In order to enhance monitoring of the CYP landslide in the HD reservoir area， this study utilized 28 descending and 24 ascending radar images from the Sentinel-1A satellite between July 2020 and July 2021. The SBAS-InSAR technique was employed to analyze and obtain the temporal deformation rates of the CYP landslide in both ascending and descending tracks. The results indicate that the maximum deformation rate in the Line of Sight （LOS） direction of the CYP landslide is -150 mm/a， with a cumulative maximum vertical deformation of -172 mm， indicating continuous sliding. By comparing and analyzing the temporal monitoring results of the ascending and descending tracks with the existing GNSS monitoring data， it was found that the vertical deformation extracted from the descending track analysis results in the CYP landslide area exhibits a high degree of consistency with the GNSS vertical deformation， aligning well with the actual situation， which can provide valuable insights for landslide identification and early warning systems. Furthermore， comparative analysis of temporal deformation with reservoir water levels and rainfall revealed a close correlation between the deformation of the CYP landslide and reservoir water levels， as well as rainfall in the area.