Continuous strong human activities have changed the mutual feedback relationship between water resources， economic society and ecological environment， and affected regional sustainable development. In order to explore the coordinated development of water resources， economic society and ecological environment in the Yellow River Basin of Henan Province and identify the drivers of coordinated development， this study improved the traditional coupling coordination degree model based on synergetics and random forest model， and calculated the comprehensive development index and coupling coordination degree of water resources， economic society and ecological environment in the Yellow River Basin of Henan Province from 2011 to 2022. The spatial and temporal evolution characteristics are revealed by kernel density estimation， and the driving factors of the coordinated development are analyzed by geographic detector model. The results showed that during the study period， the comprehensive development index of each system showed a different degree of growth trend， but there was a certain degree of heterogeneity. The water resources， economic society and ecological environment system showed a spatial disequilibrium pattern of “high in the west， low in the east， high in the south and low in the north”， “the center leads the periphery， the edge develops slowly”， “the upstream is superior to the downstream， the southwest is superior to the northeast”. The coordinated development level of water resources， economic society and ecological environment showed a significant positive trend， and the spatial heterogeneity among cities was obvious， showing the evolution characteristics of “regional rise， high in the south and low in the north， high in the west and low in the east”. Natural endowment， economic foundation and human settlement environment are the main driving factors for coordinated development， and the relationship between each factor is becoming increasingly close， and the interaction type shows a trend of transformation to “nonlinear enhancement”. This study innovatively puts forward a new method of coordinated development evaluation， and verifies its scientific nature， which provides a powerful tool for in-depth analysis of the coordinated development of water resources， economic society and ecological environment in the Yellow River Basin of Henan Province， and has certain practical guiding significance for promoting regional sustainable development.

As the severity of extreme weather escalates， the frequency of flood disasters is on the rise and the flood coincidence events may intensify the adverse effects on downstream regions. This study leverages 58 years of observed daily runoff data from 1959 to 2016 of four stations ： Wangjiaba Station and Bengbu Station on the Huai River， Jiangjiaji Station on the Shi River， and Fuyang Station on the Ying River. The study extracts the flood occurrence time series and peak flow series during the flood season using the annual maximum flow method. The marginal distribution of flood occurrence time for the annual maximum floods is constructed using the Von Mises distribution， while the marginal distributions of peaks are constructed using the logarithmic normal distribution， Pearson type III distribution， and generalized extreme value model， respectively. The parameters of each distribution are estimated using maximum likelihood estimation， the optimal model is selected according to the Akaike Information Criterion， and the Kolmogorov-Smirnov test is used to determine whether the marginal distributions are qualified. Additionally， the Vine Copula is used to construct the joint distribution of flood occurrence time and peak flow for multiple stations. Quantitative analysis of encounter risks under various conditions such as encounters between two rivers， encounters between three stations， and the conditional probability of various combinations of flooding events occurring upstream when flooding occurs downstream. The results show that the Von Mises distribution， especially the unimodal Von Mises distribution， can well fit the flood occurrence time in the Huaihe River Basin. For encounters between tributaries of the Huaihe River， the most probable date for pairwise encounters and multiple station encounters is around July 15th. Among pairwise encounters of tributaries， the highest encounter probability is between Wangjiaba Station and Jiangjiaji Station， and the lowest encounter probability is between Fuyang Station and Jiangjiaji Station. The study also reveals that， when the downstream Bengbu Station experiences the flood with the return period of 50 years， the probability of all three upstream stations experiencing the flood exceeding the 10-year return period is 0.076. This study further extends the computational methods for flood encounter risk， and it is of great significance for flood control and disaster reduction in the Huaihe River basin.

How to measure and analyze the distribution pattern and utilization efficiency of water resources in Karst area， as well as the coordination degree with the level of social and economic development， is one of the hot issues that need to be studied to improve the efficiency of water resources utilization， improve the quality of social and economic development and accelerate the construction of ecological civilization in the karst region. On the basis of collecting and processing the spatio-temporal data of water resources and social economy in karst region during 2010-2021， this paper firstly adopts super-efficiency SBM-DEA model to quantitatively measure the water resources use efficiency of 36 prefecture-level cities in the karst region of Southwest China in recent 10 years. Secondly， the spatial correlation analysis model and decoupling model are integrated to quantitatively determine the spatio-temporal difference pattern of water resource use efficiency and its adaptation state to economic development level. The results show that： in the past 10 years， the water resources use efficiency in southwest karst areas has shown an overall increasing trend， but the overall utilization efficiency is low， rising from 0.383 in 2010 to 0.484 in 2021， and the change trend of water resources use efficiency in 89% of prefecture-level cities is consistent with the overall trend. The spatial distribution of water resources use efficiency in the southwest Karst region showed an “n” shape， with relatively higher distribution near Guizhou province and relatively lower distribution near Yunnan Province and Guangxi Province. The spatial correlation of water resources use efficiency was not obvious， but the degree of agglomeration showed an increasing trend. The degree of adaptation between water resources efficiency and economic development level showed an increasing trend， but the types of expansionary negative decoupling increased significantly.

To solve the problem that deterministic streamflow forecast can not provide the uncertainty measurement of streamflow forecast and is difficult to give full play to the forecast value， this paper proposes a Vine copula-based Bayesian Transition Forecast （VCBTF） model to obtain the probability forecast result by post-processing the deterministic runoff streamflow results. Firstly， the ensemble results of the streamflow forecast were obtained through a variety of hydrological forecasting empirical models. Secondly， the ensemble Kalman filtering technology was used to fuse the ensemble results of the forecasted streamflow into the posterior forecast results. Finally， the VCBTF was used to post-process the fused streamflow forecast results to quantify the uncertainty of the runoff forecast and obtain the probabilistic forecast results of the flow. Taking Lianghekou Reservoir with multi-year regulation capacity in the Yalong River Basin as a case study， the medium and long-term streamflow probability forecast is carried out. The results show that： ① The VCBTF model is superior to the deterministic runoff forecast model in terms of Root Mean Square Error， Mean Absolute Error and Nash-Sutcliffe efficiency index， and the Qualified Rate of forecast is increased by at least 2.7%； ② The average value of continuous probability ranking score index of the VCBTF model is 104.54 m³/s， which is better than that of the GPR model with 106.92 m³?/s， and the α-index of the VCBTF model is higher than 0.89 and better than the corresponding result of the GPR model， indicating that the probabilistic forecast results based on the VCBTF model have higher reliability； ③ The average value of the Percentage of measured points contained in the Unit Confidence Interval of the VCBTF model is 2.2， which is better than that of the GPR model with 1.87， indicating that the probabilistic prediction results of the VCBTF model have a higher concentration. Therefore， the VCBTF model proposed in this paper can more effectively reduce the forecast uncertainty of streamflow， and provide more reliable forecast interval information. It can provide strong technical support for the optimal operation of cascade reservoirs in the basin.

Rapid urbanization has led to changes in land use patterns and runoff characteristics， resulting in frequent urban waterlogging problems. Predicting the future land use changes and exploring the evolution of urban waterlogging risk can provide reference basis for improving urban disaster prevention and reduction planning. This article takes Nanjing as an example and uses the FLUS model to predict the land use patterns in 2030. Combining the MaxEnt model and risk assessment index system， the main influencing factors of urban waterlogging risk and their contributions are identified. Moreover， the waterlogging risk pattern and its evolution under the land use scenarios are analyzed. The results indicate that： ①The main characteristics of land use changes in Nanjing are a decrease in cropland and an increase in construction land. It is estimated that the cropland area in Nanjing will decrease by about 2.6% and construction land will increase by about 4.81% between 2020 and 2030； ② Indicators such as land use type and distance from roads have a high contribution rate to the distribution of waterlogging risk in Nanjing， while indicators such as the number of days with daily precipitation exceeding 50mm and total precipitation have significant importance. ③ The proportion of high-risk areas in Nanjing in 2010， 2020， and 2030 was 4.77%， 5.37%， and 5.94%， respectively. The high-risk areas are mainly distributed in the central urban areas along the Yangtze River， with the high-risk areas in Gulou District， Qinhuai District， and Xuanwu District accounting for over 50% of the total in 2030； ④ With the change of land use pattern， there is a 23.36% probability that medium-high-risk areas will be transformed into high-risk areas， and a 21.74% probability that medium-risk areas will be transformed into higher risk areas. Overall， the risk level shows an increasing trend.

Reservoir flood control scheduling is crucial for effectively reducing flood disasters and ensuring the safety of lives and property. This process is a multi-stage， nonlinear， high-dimensional engineering problem with complex constraints and interdependent decision variables. To improve the efficiency of solving the optimal scheduling problem of reservoir groups and fully utilize their coordinated flood control capabilities， this paper proposes an Improved Sand Cat Swarm Optimization Algorithm （SCSO）. The algorithm incorporates the Cubic chaotic mapping strategy to enhance the dispersion and uniformity of the scheduling plan. Additionally， the whale algorithm's spiral search strategy is introduced to improve the population's local and global search capabilities， and the sparrow algorithm's warning mechanism is integrated to boost global search ability in later stages. The algorithm's accuracy is validated using classical test functions and rank sum tests. Results demonstrate significant improvements in the convergence speed and accuracy of the improved Sand Cat Swarm Optimization （ISCSO） algorithm. For the first time， this algorithm was applied to the optimization and scheduling of flood control in reservoir groups. A maximum peak shaving criterion model was established at flood control points， and the joint flood control scheduling system for five reservoirs in the middle and lower reaches of the Yellow River was studied. Comparative analyses were conducted with the original Sand Cat Swarm Optimization （SCSO） and the Dung Beetle Optimization （DBO） algorithms. The peak flow rate at control points obtained by the DBO algorithm was 21 274.3 m3/s， with a peak shaving rate of 46.62%. The SCSO algorithm yielded a peak flow rate of 21 248.6 m3/s， with a peak shaving rate of 46.68%. The ISCSO algorithm achieved a peak flow rate of 20 687.1 m3/s， with the highest peak shaving rate of 48.09%. These results indicate that the ISCSO algorithm achieves the best peak shaving performance for reservoir flood control scheduling， effectively shifting downstream peaks and ensuring the safety of downstream rivers and flood control points. The findings of this research provide new insights and methods for optimizing flood control scheduling in reservoir groups.

Climate change and human activities have increasingly significant impacts on the ecological health of the Dawen River. To maintain the stability of river ecological health， it is crucial to carry out ecological flow evaluation. This study focuses on the the Jinan section of the Dawen River Basin， utilizing multi-source remote sensing data to extract water body area information. A fitting equation is constructed from the water body area and the measured flow， to determine the ecological water body area corresponding to the basic ecological flow. Ecological flow evaluation is then conducted based on remote sensing data. Research results show that，from 1985 to 2021， the water body area of the Jinan section in the Dawen River Basin is 41.84 km²， and the water body area shows an increasing trend， of which seasonal water bodies account for 32% and permanent water bodies account for 68%. Among the six water body indices， EWI and NDWI are suitable for the Jinan section of the Dawen River basin， with an accuracy of 90%. Through linear fitting analysis， the ecological water body areas of the Chenbei and Maxiaozhuang watersheds are 13.98 km² and 18.49 km² respectively. The ecological flow guarantee rates from 1985 to 2021 are 65% and 42% respectively. Affected by natural factors and human factors， significant changes in the ecological flow guarantee rates were observed around 2004， increasing from 43% and 7% to 83% and 73% respectively， and reach 100% by 2020. Cross wavelet and wavelet coherence spectrum analysis results show that the water body area is positively correlated with the climate factors of precipitation and average humidity， negatively correlated with average wind speed， and has no significant coherence with average temperature. Precipitation and average humidity are the main factors affecting changes in the water body area. Among land use factors， changes in water body area are mainly affected by the area of cultivated land and grassland， showing a negative correlation. Based on the different water body areas ratio in the basin， it is determined that the ecological water body area of Xueye Reservoir is 10.82 km²， the ecological water level is 228.97 m and the ecological storage capacity is 102 million m³. The research results can provide technical support for ecological flow evaluation， supervision and dispatch in the Dawen River Basin.

In the practical processes at water purification plants， the water quality is complex and variable， and there are instances of missing water quality parameters due to malfunctioning detection instruments， thus bringing challenges to determining the dosage of coagulants. Traditional methods， such as beaker stirring tests or manual control of excessive dosage， can easily bring water quality risks such as excessive metal ions， posing health risks to users and reducing economic efficiency. To address these issues， a predictive model combining Genetic Algorithm optimized Fuzzy C-Means clustering （GA-FCM） and Adaptive Neuro-fuzzy Inference System （ANFIS） was developed. This model leverages the inference capability of fuzzy rules and the adaptive capability of neural networks to accurately predict coagulant dosage under unstable water quality conditions.Pearson correlation coefficient method was used to filter input water quality indicators， enhancing model efficiency and generalization capability. The genetic algorithm was employed to determine the optimal parameters for FCM clustering， improving clustering outcomes and generating more accurate fuzzy rules. A hybrid method combining backpropagation and ridge regression was used to adjust network parameters， addressing nonlinear components while optimizing the weights of the consequent network. A water purification plant in Northeast China was used as a case study. Experimental results indicated that compared to traditional linear regression and machine learning models， GA-FCM-ANFIS exhibited superior predictive performance under unstable water quality conditions. Furthermore， in the absence of certain parameters， GA-FCM-ANFIS achieved significantly higher predictive accuracy than other coupled models. The prediction evaluation metrics R ²， RMSE， MAE， and MAPE under sudden water quality changes were 0.93， 2.79， 2.33， and 3.71%， respectively； under missing parameters， the metrics were 0.89， 3.07， 2.57， and 4.06%， respectively. The proposed model significantly improves prediction accuracy and serves as a reliable method for determining coagulant dosage.

Changes in shoreline morphology are closely related to the distribution of water resources， directly affecting the stability and health of aquatic ecosystems such as lakes and rivers. However， the high dynamics of Poyang Lake， characterized by “expansive waters in flood seasons and contracted waters in dry seasons”， pose challenges for continuous shoreline morphology studies. This paper synthesizes annual data from 1987 to 2021 using the Google Earth Engine cloud computing platform and employs the Canny-Otsu algorithm to extract the shoreline of Poyang Lake. Morphological indices are then applied for quantitative analysis. The study reveals that over 35 years： ① The shoreline of Poyang Lake is mainly distributed at the junction of the main lake area and the butterfly-shaped lake area， exhibiting significant interannual variability with notable instability， but the spatial orientation of the shoreline remains relatively stable， with minor and irregular centroid movements； ②The shoreline of Poyang Lake is rich in resources， with an average length of 1 111 km， characterized by a longitudinally flattened and intricately convoluted shape， with mean SDI and SBD values of 8.53 and 1.36， respectively； ③ As the lake area gradually decreases， shoreline resources diminish accordingly， with shoreline morphology tending towards longitudinal flattening and increasing complexity and irregularity； ④The circularity and SDI values of the Poyang Lake shoreline are primarily influenced by the lake area， while the SBD value is mainly determined by the shoreline length. These findings can provide a scientific basis for the formulation of ecological protection strategies and are significant for understanding the morphological evolution of the Poyang Lake shoreline.

This paper proposes a Transformer-based local timestep two-dimensional hydrodynamic simulation method aimed at optimizing the speed and accuracy of flood simulations to meet the urgent needs of flood prevention and mitigation. By incorporating the self-attention mechanism and sequence prediction capabilities of the Transformer model， combined with local timestep techniques， this method dynamically adjusts the local timestep in the hydrodynamic system. Using the real flood process in the Mengwa flood storage area as an example， the simulation results demonstrate that， compared to remote sensing inundation imagery and traditional numerical methods， this approach shows higher consistency and reliability in the precise prediction of inundation extent and depth， maintaining a relative error within 4%. Compared to traditional global timestep methods， this method significantly reduces computational time while ensuring simulation stability and accuracy， achieving a 70.27% improvement in computational efficiency at a 150 m grid resolution.

In order to explore the level of benefits， evolution patterns， and obstacle factors after the implementation of key soil and water conservation projects in the Gansu section of the Yellow River Basin， an evaluation index system for the comprehensive management benefits of soil and water conservation was constructed based on the theme framework of "water and soil conservation， ecology， economy， and society". The entropy weight TOPSIS and coupling coordination model were used to quantitatively evaluate the spatiotemporal evolution process of the comprehensive benefits of soil and water conservation in 9 cities and prefectures of the Gansu section of the Yellow River Basin from 2000 to 2021， as well as the coupling coordination between subsystems. The obstacle degree model was introduced to identify the obstacle factors for improving the comprehensive benefits of soil and water conservation. The results show that from 2000 to 2021， the comprehensive management benefits of soil and water conservation in the Gansu section of the Yellow River Basin have been increasing year by year， transitioning from an extremely deteriorating state in 2000 to a good state in 2021； There were significant spatial differences in the benefits of comprehensive soil and water conservation management among the 9 cities and prefectures. Lanzhou， Baiyin， and Pingliang had higher benefits of comprehensive soil and water conservation management， but the gap between cities and states showed a good trend of narrowing year by year； The development level of water and soil conservation， ecological， economic， and social benefit systems all showed an increasing trend year by year， and the development level of ecological benefit systems lagged behind that of water and soil conservation， economic， and social benefit systems； The coupling coordination degree of the comprehensive management benefits system for soil and water conservation in the 9 cities and prefectures showed an increasing trend year by year， transitioning from a stage of mild imbalance to a stage of good coordination， and the spatial performance of the 9 cities and prefectures were relatively balanced； The main obstacles to the improvement of comprehensive soil and water conservation benefits in the Gansu section of the Yellow River Basin are the water production modulus， surface runoff depth， plant carbon sequestration， plant oxygen release， and per capita total power of agricultural machinery. Research has shown that the comprehensive management benefits of soil and water conservation in the Gansu section of the Yellow River Basin have become increasingly apparent over time， and the overall direction is constantly developing towards health， coordination， and balance. At the same time， there is still significant room for improvement in the comprehensive management of soil and water conservation and modernization of agricultural production conditions.

The rational layout of spur dikes has a significant impact on the flow structure， patterns of fluvial erosion and deposition. In addition to serving as a protective measure for riverbanks， these dikes also play a role in promoting the formation of various riverbed features， such as deep pools and shallow shoals nearby. These unique characteristics create a rich habitat for aquatic organisms， thereby enhancing ecological sustainability and development. Using the computational fluid dynamics （CFD） technique and the RNG k-ε model for parameter calibration and verification， this study undertakes a rigorous investigation into the hydrodynamic properties and the fluvial erosion-deposition processes occurring in the vicinity of spur dike units with diverse deflection angles situated at the concave bank of a 180° bend. The results indicated that， in relation to energy dissipation and water level fluctuations， the spur dike with a 90° deflection angle exhibited the most prominent characteristics， yielding the greatest water level disparities and the most significant energy losses. The spur dike exhibiting an upward deflection angle occupied a secondary position， whereas the spur dike with a downward deflection angle demonstrated the least noteworthy effects. Furthermore， a positive correlation was identified between vortex intensity and the degree of riverbed erosion and deposition. Counterclockwise vortices contributed to deposition， whereas clockwise vortices were prone to cause erosion. In terms of the distribution of shear stress， the scope and magnitude of the intense shear stress zones formed at the head of the spur dike and on the opposite bank exhibit a distinct pattern where the spur dike with a 90° deflection angle shows the largest impact， followed by the upward deflection spur dike， and the downward deflection spur dike demonstrates the smallest impact. So， the selection of deflection angles for spur dikes significantly influences riverbed scouring and deposition， water flow characteristics， and ecological outcomes. It is crucial to scientifically and rationally design and arrange spur dikes to achieve a balance between controlling riverbed scouring and deposition， preserving ecological balance in river channels， and ensuring the safety of engineering projects.

Rural sewage treatment is a concrete measure to effectively promote the comprehensive revitalisation of the countryside， and is also an important element in improving the rural living environment and building a beautiful and livable countryside. As China′s urban sewage treatment capacity continues to improve， rural sewage treatment is also categorised to advance step by step. However， the poor operation of rural sewage treatment facilities restricts the effectiveness of rural sewage treatment. There are still problems such as mixed processes， scattered distribution， low operational efficiency in China’s rural sewage treatment， and part of the construction and operation of rural sewage treatment facilities are not well matched with the actual situation. Therefore， in-depth analysis of the current situation and existing problems of rural sewage treatment construction and operation management， and improving the matching degree of construction and operation of rural sewage treatment facilities are of great significance to solve the practical difficulties faced by China's rural sewage treatment. This study takes rural sewage treatment facilities in a city in North China as the research object. Based on the local water authorities and the basic data in the statistical yearbook， the data set is compiled and the data outliers are processed in combination with the field survey and the expert advisory meeting opinions. The factors affecting the matching degree of rural sewage treatment facilities of different types of plants and stations in the region are screened and analyzed. The results show that controlling the population， controlling the GDP of the plant and station， and designing the sewage treatment capacity are the more critical factors affecting the matching degree of the construction and operation of rural sewage treatment facilities in a certain area. It is suggested that in the process of operation， maintenance， optimization and upgrading of rural sewage treatment facilities， the key factors should be considered comprehensively， and the decision-making should be tailored to local conditions and from multiple perspectives， so as to realise the economic and efficient operation of rural sewage treatment facilities and to give greater play to the benefits of the ecological environment.

As the mother river of Northeast China， assessing the value of water ecosystem services of the Songhua River Basin is of great significance to the sustainable development of the Songhua River Basin ecosystem. Using 2020 as the base year， this paper adopts the InVEST model method， market value method， equivalent factor method， apportionment method and other evaluation methods to quantitatively assess 12 indicators of the Songhua River Basin， including water resource supply， fishery products， hydroelectric power generation， river sand mining， water conservation， water purification， carbon sequestration and oxygen release， biodiversity， soil preservation， recreational tourism， inland shipping， and scientific research and education.The results show that the total value of water ecosystem services in the Songhua River Basin in 2020 is 590.732 billion yuan， accounting for about 43.12% of the GDP of Heilongjiang Province in 2020. The value of regulating function accounted for 72.32% of the total value of water ecosystem services， taking the first place； the value of supporting function and service function accounted for 10.63% and 12.20%， respectively； and the value of providing products was the smallest， only 4.84% of the total value. This paper scientifically establishes the evaluation system of water ecosystem service value in Heilongjiang Province， which provides scientific basis and data support for accelerating the construction of compensation mechanism and proposing practical ecological compensation countermeasures.

This study provides a comprehensive analysis of the erosion and deposition patterns in the mainstream area of the Three Gorges Reservoir （TGR） in 2022， considering the dry water conditions in the second half of the Yangtze River Basin. The analysis is conducted in conjunction with the operation of the reservoir. The results show that the inflow of the TGR in 2022 in the flood season is significantly less than that in previous years， showing a reverse dry phenomenon. At the same time， the amount of incoming sediment in flood season also decreased significantly. The annual sediment deposition in the TGR area is 0.11 billion tons， which is the lowest in history since the establishment of the reservoir. There is also a rare whole river erosion in the flood control reservoir capacity. During the drawdown period， the incoming water in the upper reaches of the Yangtze River is relatively abundant， and the water level in front of the dam drops rapidly. The scouring volume at the tail of the reservoir was large， and the effect of sediment reduction scheduling during the drawdown period is remarkable. The anti-dry phenomenon in the flood season in 2022 results in a significant decrease in the amount of siltation in the TGR area during the flood season compared with the normal year. From June to September， the amount of siltation in the mainstream of the TGR area was 4.74 million tons， accounting for only 41.7 % of the annual siltation. In addition， the low water level in the flood season also leads to the low water level in front of the dam for a long time in the flood season of the TGR in 2022. This is also the main reason for the significant increase in the erosion intensity of the river section in front of the dam compared with previous years.

Meandering channels are frequently observed in natural environments， and studying the dynamic behavior and evolution of the bed surface within meandering channels under the influence of clear water erosion has emerged as a crucial area of research. In this article， the primary objective is to devise an innovative experiment， namely a cascade flow increase test， in order to comprehensively investigate the alterations occurring in the bed surface of a meandering channel when subjected to the erosive forces of clean water. The research shows： Under the same flow rate， near the entrance and middle of the straight transition section， the average cross-sectional velocity is relatively high. The entrance of the straight transition section is prone to sedimentation and erosion， and the degree increases with the increase of flow rate. When the flow rate is small， the sediment in the straight transition section is finer than that in the curved section. As the flow rate increases， the sediment gradation in the straight transition section tends to be the same as that in the curved section. Within a complete bend section， the talweg is close to the convex bank in the bend section and closely adheres to the edge wall in the straight transition section. After being shaped by flow， the frequency distribution of bed elevation gradually changes from normal to normal skewed.

When the regulating valve operates under high flow rates and high pressure differentials， cavitation phenomena are prone to occur in the throttling area， resulting in abnormal vibration and noise in the valve body， and even damage to the valve body. Taking the DN200 flow-pressure-regulating plunger valve as the research object， based on the Siemens LMS data acquisition system， the underwater noise signal of the regulator valve is measured at different openings and cavitation numbers， and the root-mean-square （RMS） value of the underwater cavitation noise is calculated. The cavitation number-noise curves at different openings are plotted， obtaining the initial cavitation number， sustained cavitation number， and some openings also determine the obstructed cavitation number. The results indicate that the flow control valve exhibits better resistance to cavitation at smaller openings. As the valve opening increases， both the initial cavitation number and sustained cavitation number increase rapidly initially but then increase slowly after 70% opening， following a parabolic growth pattern. The results of the study provide certain guidance for determining the characteristic cavitation coefficient curve， monitoring cavitation status， optimizing vibration reduction and noise control design， and ensuring the safe operation of flow-pressure-regulating plunger valves.

With the continuous development of information construction in water conservancy engineering， implementation of smart water conservancy and digital twin continues to deepen. BIM technology has been introduced into the operation and management system of water conservancy engineering to realize the characteristics such as management visualization and real-time data. In order to accurately display the internal flow status of the pump device in the operation and management of large pumping station， while reducing computational costs and time， a idea of joint application of BIM and CFD technology is proposed based on the operation and management system of Xifeihebei Station. By conducting CFD calculations under a large number of operating conditions in advance， and processing the calculation results into the required characteristic cross-sectional flow status charts， a flow status charts database for different operating conditions is built， and then the closest flow status chart is selected and displayed based on the real-time operating conditions. The research result has been applied in the operation management system of Xifeihebei Station， providing an example for similar engineering applications.

To investigate the pressure pulsation characteristics of pump-turbine during the pressurizing phase， a prototype pump-turbine was taken as the research object. Comparative analysis was conducted for the flow regime and pressure pulsations of the runner and vaneless region of a prototype pump-turbine with two typical starting-up processes using Computational Fluid Dynamics methods. Results show that the average value of simulated pressure is close to the experimental value with the relative deviations of 2.738% and 2.103%， respectively， when employing the balance tube. It is also found that large-scale stall vortexes are formed in the inter-blade channels of the runner， while the flow characteristics with “water ring” is induced in vaneless region when the guide vane is closed during the pumping pressurizing phase. In contrast， when it is pre-opened at 0.78° to complete the pumping pressurizing phase， the flow in the inter-blade channels of the runner is relatively smooth with small-scale vortexes and partial blockages. Besides， the runner blade passing frequency （10 f_n ） is the primary component at each measuring point. There are abundant frequency components in the range of 0~10 f_n， which have lager influences on the pressure pulsation in vaneless region. For the pressurizing phase with closed guide vane， the amplitude of pressure pulsation at each measuring point is significantly higher than that in the pre-opening state. In addition， the peak-to-peak value of 0~10 f_n and the corresponding amplitude of 10 f_n on the upper crown of vaneless region are both higher when the pressure balance tube is employed， due to the different degrees of influence on the flow in vaneless region and the flow rate through runner.Taking into account the amplitude of pressure pulsations during the startup process， as well as the stability of self-excited torsional vibrations experienced by the guide vanes at extremely small opening， it is recommended for high-head pump-turbines to prioritize the startup process which completes the pumping pressurizing phase with pre-opening guide vanes.

To cope with the change of inflow runoff caused by climate change， many old reservoirs need to evaluate the change of discharge capacity of spillway after installing retaining wall or other renovation measures， to formulate safe operation and management measures of reservoir. Taking an old reservoir as a study case， the formula of the correction coefficient of weir pier， a unified formula for calculating the discharge capacity of different weir flow type， the classification method of weir flow type were obtained based on theoretical analysis， the relationship between water level and discharge and the flow type of weir flow are observed through physical model tests， and then the relation of the correction coefficient for weir pier and comprehensive discharge coefficient with water head and the change condition of flow type are determined based on the observed data. The research results show that： the discharge capacity of weir flow is significantly different for weir flow and orifice flow， the unified formula is suitable and practical for such case， the relationship between the comprehensive discharge coefficient and the water head is quadratic for weir flow and linear for orifice flow， and the relationship between the coefficient of pier correction and the ratio of water head and pier shape parameters is an approximate linear. These results can be used as a theoretical basis for the assessment of the discharge capacity of the spillway of hydropower station with the addition of retaining wall to the dam roof to cope with climate change.

In order to improve the safety and stability of hydropower unit operation， monitor the unit's operation status in real time， and accurately and efficiently determine the probability of the rotor grinding fault of hydropower units， a fault determination model based on the combination of subjective-objective combined weighting method and fuzzy theory is proposed. Firstly， the symptom indexes corresponding to the rotor grinding fault are extracted， and a “fault - symptom index” judgment structure system is constructed. Secondly， the Analytic Hierarchy Process （AHP） and Technique for Order Preference by Similarity to an Ideal Solution （TOPSIS） are used to obtain the subjective and objective weights of each symptom index， and the comprehensive weights are calculated based on the maximum extreme difference combination method. The Gauss threshold method is used to determine the limit value of oscillating signs， and the industry standard is used to determine the limit value of temperature signs. The deviation degree of hydropower units is determined based on the limit of signs， and the mapping function of “deviation degree-membership degree” is constructed， and the membership degree judgment matrix is obtained. The fault judgment matrix is obtained by combining the membership decision matrix with the comprehensive weight， and the fault probability is reflected according to the maximum membership degree of the fault judgment matrix. Based on the actual operation data of the SK hydropower station， the fault judgment model of rotor grinding fault is verified， and the judgment results are consistent with the actual fault situation.

During the process of reservoir migrant relocation and resettlement， different resettler families gradually formed different livelihood strategies. In order to systematically study the main factors influencing the selection of livelihood strategies of resettlers， a research model for the selection and behavior of livelihood strategies of resettlers based on the DEMATEL-ISM method was established. Based on field investigations of LJ Reservoir， this study analyzed the factors that influence the choice of resettlement methods for resettlers， the recovery of their livelihoods， and their livelihood behaviors from the perspectives of policy situations， internal family factors， and the their livelihood environment. The study also discussed the conditions for achieving the optimal state of the livelihood system for resettlers. The results indicate that the influencing factors of livelihood selection and behavior have a multi-level hierarchical nature. ‘The Number of income sources’ is the most important criterion for determining livelihood strategies of resettlers， while ‘the number of labor force’， ‘educational level of the family’， and ‘local characteristic industries’ are the root factors that influence the selection and behavior of livelihood strategies of resettlers. Based on these findings， suggestions for development are proposed， such as promoting the development of characteristic industries based on local resources and improving the entrepreneurial and employment capabilities of resettlers based on market demand. These suggestions provide references for achieving the long-term development of resettlers themselves and for the government to adopt supportive development strategies in the later stages.

The construction of water resources projects has changed the hydrological situation of downstream rivers and adversely affected river habitats. Under the engineering background of the whole river canalization of the Jialing River， the slow-flowing river section formed by the cascade navigation and hydropower project will not be able to provide suitable drifting conditions for drifting fish eggs， which will sink and die， and the fish resources will shrink. This paper proposed an ecological scheduling program for the Lize navigation and hydropower project in response to the problem of impeded hatching of drifting fish eggs in the main stream of the Jialing River. Firstly， a one-dimensional hydrodynamic model was established from Tongzihao navigation and hydropower project to CaoJie navigation and hydropower project， and the reliability of the model was verified； Secondly， the flow rate threshold for drifting fish egg hatching was determined， according to which the ecological scheduling plan for the Lize navigation and hydropower project was formulated； Finally， the economic benefits loss due to ecological water discharge was calculated according to the scheduling rules of the Lize navigation and hydropower project. The results show that the correlation coefficient between the one-dimensional hydrodynamic model simulation results and the actual runoff is 0.88， and Nash efficiency coefficient is 0.78， which can effectively reflect the simulation of the flow velocity change process of the simulated river section. The minimum underflow of 1 550 m³/s on the first day， 1 820 m³/s on the second day， 2 000 m³/s on the third day， 2 400 m³/s on the fourth day， 1980m³/s on the fifth day， and 1 550 m³/s on the sixth day of the Lize ecological scheduling is formulated， which can meet the flow rate requirements of drifting fish spawn； when the natural runoff cannot be met， the Tingzikou Reservoir is required to cooperate in joint eco-operation. This study may provide technical support for ecological scheduling studies that consider the hatching needs of drifting fish eggs.

The external water pressure of lining is of great significance to the determination of lining thickness and drainage scheme of water-rich deep buried tunnel. The existing research often ignores the analysis of the influence of macroscopic geological conditions on the seepage field， which leads to the lack of reliability evaluation of the external water pressure estimation results and lining design schemes of deep buried tunnels. Based on the Qinling Water Conveyance Tunnel Project of Hanjiang-to-Weihe River Diversion Project， this paper generalizes the deep-buried tunnel in the water-rich area into three representative macro-geological environment models under the watershed， the mountainside area and the river， and studies the influence law and mechanism of geological conditions and engineering measures on the seepage field of surrounding rock and the external water pressure of lining. The results show that： ① The seepage direction of groundwater around the watershed tunnel is mainly vertical under the condition of the same height of groundwater at the top of the tunnel and impermeable lining. The seepage direction of groundwater around the tunnel under the river is mainly horizontal. The external water pressure reduction coefficient of the watershed tunnel， the tunnel near the mountain area and the tunnel under the river increases in turn. The reduction coefficient of external water pressure of tunnel under watershed increases with the increase of buried depth， which is 0.72，0.77 and 0.84 respectively. The reduction coefficients of the external water pressure of the mountain tunnel and the river tunnel are almost unchanged， which are 0.91， 0.91， 0.93 and 0.95， 0.96， 0.96， respectively. ② After the same drainage measures are taken， with the increase of buried depth， the reduction coefficients of external water pressure of watershed tunnel are 0.15，0.42，0.64 respectively， and the pressure reduction effect is the best. The external water pressure reduction coefficients of the tunnel near the mountain and the tunnel under the river are 0.48，0.67，0.77 and 0.63，0.80，0.83， respectively， and the pressure reduction effect gradually deteriorates. ③ When the buried depth of the tunnel is 1 200 m， the reduction coefficients of external water pressure of the watershed， mountainside and river tunnel are 0.43~0.73， 0.67~0.89 and 0.80~0.95 respectively with the increase of the permeability coefficient of the surrounding rock， which shows the regularity that the external water pressure increases with the increase of the buried depth of the tunnel. The research results are universal， and the rationality of water pressure resistance design of tunnel lining in water-rich area can be evaluated from the regularity of macroscopic hydrogeological conditions of tunnel and reduction coefficient of external water pressure.

In order to address the significant manual costs incurred during template measurements due to prism placement and manual observations， as well as to mitigate the safety hazards associated with working aloft， this paper proposes a vision-based AI-driven continuous template automatic measurement approach. Employing an image total station as the primary sensing device， the method utilizes machine vision algorithms to replace manual observation methods for the automated detection and measurement of continuously rising templates at dam construction sites. This approach enhances the efficiency of dam construction layout and reduces the workload for measurement personnel. The method incorporates concentric circles with numerical markings as collaborative targets to replace prisms， and employs a circle center detection algorithm based on cross ratio invariance for precise identification and positioning of measurement points. Additionally， a DP controller is applied to achieve accurate alignment of the image total station. Experimental measurements were conducted at the TB dam pouring site using the image total station Leica TM50I for automated measurements. The results demonstrate that within a testing distance of 70 to 131 meters， the error between this method and traditional manual measurements is within 5 mm.

In order to study the influence of the position of the inner tooth on the hydraulic performance and anti-clogging performance of the toothed bidirectional flow channel emitter， a toothed bidirectional flow channel emitter with superior hydraulic performance and anti-clogging performance was proposed by synchronous optimization. The computational fluid dynamics software Fluent was used to numerically simulate the emitters of five different toothed bidirectional flow channels （ including the improved flow channel structure ）. The flow index， flow velocity， turbulent kinetic energy， turbulent kinetic energy dissipation rate distribution law and physical particle motion trajectory of different toothed bidirectional flow channels were analyzed. The results show that when the inner tooth is located on the inlet of the branch channel， the flow index of the emitter is the smallest， and the area of the turbulent kinetic energy dissipation rate of 2 000~4 000 m²/s² is larger than that of the other three schemes. By comparing and analyzing the minimum turbulent kinetic energy， sand migration distance， and sand retention time of the four schemes， it is concluded that when the inner tooth of scheme 1 is located on the inlet of the branch channel， the anti-clogging performance of the toothed bidirectional channel is the best. The streamline optimization of the inner tooth structure of scheme 1 is improved， which further improves the hydraulic performance and anti-clogging performance of the toothed bidirectional flow channel.

The Mid-route of South-to-North Water Transfer Project mainly uses open channels for water transportation， with long distances and large spans along the route， and significant differences in climate between the ends of the channels. Low temperature can cause ice to appear in the channel， posing great challenges to the operation and scheduling of the channel. The bottom layer warm water of the Xiong’an reservoir near the Xiheishan check gate is diverted into the channel to increase the channel water temperature， bringing new ideas for regulating the channel ice condition. This article establishes a one-dimensional channel ice hydraulic simulation model considering the inflow of warm water from the side， and conducts simulation research on the changes in water temperature and ice conditions inside the channel after warm water flow into the channel. The channel model was constructed based on the main canal of the Beijing-Shijiazhuang section as the prototype. By setting different inflow ratios， inflow temperatures， mixed discharges， and inflow times， the variation patterns of water temperature and ice cover thickness along the channel under different inflow conditions were explored. The results indicate that： ① the idea of using offline reservoir charging to alleviate channel ice conditions is basically feasible， but the impact of the inflow from the regulating reservoir on the water temperature of the main channel is mainly within the downstream 20km channel. The closer the channel is to the downstream， the less affected it is， and the longer the delay time of water temperature rise. ② The higher the proportion of incoming water from the reservoir， the more significant the impact on the water temperature of the canal. ③ The higher the temperature of the inflow water from the reservoir， the more significant the effect of improving the water temperature of the downstream channel pool， and the duration of the ice cover is significantly shortened， but the range of ice formation is not significantly reduced. ④ The larger the mixed discharge， the slower the water temperature decreases， and the closer the section with ice is to the downstream. ⑤ In actual scheduling， it is necessary to combine meteorological forecasts and start adding warm water to the channel before the winter cools down， and continue throughout the entire low-temperature period to achieve the best ice relief effect. The research results of this article can provide data support for the determination of alleviating the ice condition by water inflow， serve as a reasonable reference for the feasibility of engineering， and also provide reference for the calculation and simulation of other similar temperature mixing problems.

To better reveal the dynamic damage characteristics of Cemented Sand and Gravel（CSG） materials， the concept of breakage energy dissipation is employed to define the damage variable for CSG materials under cyclic loading. The evolution of damage characteristics of CSG materials under different confining pressures and cement contents is investigated from an energy perspective. The research findings indicate that with increasing strain， the total energy and dissipated energy increase， while the elastic energy first increases and then decreases. With the increase of confining pressure and cement content， the energy storage limit and maximum dissipated energy exhibit nonlinear growth. The proportion of dissipated energy at the yield point gradually increases， while the proportion of dissipated energy at the peak point decreases， indicating that the confining pressure improves the material’s resistance to lateral deformation and efficiency of energy accumulation. The damage variable of CSG materials demonstrates four-stage characteristics， with the maximum amplification occurring during the crack propagation stage， gradually rising and approaching 1 during strength failure.

Retrogressive erosion is a rapid erosion phenomenon commonly occurring in reservoirs or sedimentation basins， which can swiftly remove substantial amounts of previously accumulated sediment within a short period. However， mathematical models capable of accurately predicting the retrogressive erosion process in real scenarios are relatively scarce. Therefore， this paper establishes a water-sand coupled retrogressive erosion model based on the sediment entrainment theory under high-speed erosion conditions. The sediment entrainment theory under high-speed erosion conditions is analyzed to establish a nonlinear equation about the erosion rate. A numerical solution method to slove the nonlinear equation is proposed to obtain the net vertical sediment flux in the governing equations. The retrogressive erosion model is discretized by the one-dimensional finite volume method and the HLLC approximate Riemann operator is used to solve the numerical fluxes. Using the retrogressive erosion model， the non-flood season retrogressive erosion process of the sedimentation basin in the Yangwu River irrigation district in 1982 was simulated. The model was validated using measured water level data and cumulative sediment erosion data. The NSE values for calculated water surface elevation were 0.621， 0.936， 0.973， and 0.949， respectively. The relative error between the model-calculated cumulative sediment erosion and the measured values was 1.8%. The calculated results showed that the retrogressive erosion model established in this paper could accurately simulate the retrogressive erosion process. The model was used to investigate the influence of the unsteady inflow process on the amount of retrogressive erosion. The results indicate that under a constant total water volume during the retrogressive erosion process， improving the peak flow rate and delaying the occurrence of peak flow can lead to better erosion outcomes

Aiming at the problem of side wall damage of differential flip bucket in a wide-shallow spillway during flood discharge， prototype observation and numerical simulation were used to study the differential flip bucket. Preliminary test results show that the combined action of negative pressure and high flow velocity at the side wall of differential flip bucket is the main cause of cavitation damage. It is proposed to increase the cavitation resistance of differential bucket by adding fishtail bucket with appropriate width at the end of differential bucket. By using an orthogonal test， it is found that with the increase of fishtail bucket width， the pressure and cavitation number of each measuring point increase obviously， and the bottom plate pressure between buckets increases with the increase of differential bucket height. The highest point of the water surface line of the spout is different in the high， middle and low ridges， which are 2.59， 0.89 and -1.41 m higher than the original design. The energy dissipation rate of each differential bucket is above 40%. The anti-cavitation performance and the hydraulic characteristics of the flip bucket with middle bucket + 1.0 m fishtail bucket can meet the actual needs of the project， and it can be used as a recommended repair shape. The research results can provide a reference for the optimization design of similar differential flip bucket.

Water scarcity， pollution， and ecological degradation in irrigation areas significantly jeopardize regional food security and social stability. It is essential to systematically tackle the issue of water security in irrigation regions. This study utilizes the 3E management concept， focusing on a groundwater irrigation district in the Hebei Plain as a case study， and formulates an integrated model for water resources and environmental management for farmers in groundwater irrigation areas， which aligns with targets for water consumption （ET）， environmental capacity（EC）， and ecological services （ES）. The model is fundamentally grounded in system dynamics theory， with two modules for assignment of target values for ET/EC/ES and simulation & assessment of measurements， and can effectively allocate the comprehensive management responsibilities for the protection of water resources， the water environment， and ecological conservation in irrigation areas to farmers while also quantitatively simulating and assessing the performance of 3E target attainment before and after the implementation of adjustment measures by farmers. The results demonstrate that the established comprehensive management model effectively allocates regional 3E targets to farmers while delineating the groundwater extraction limit and fertilizer application limit for each farmer to facilitate regional 3E target management. The model can statistically evaluate the farmers' enhancement strategies from multiple perspectives， including water use， water consumption， pollutant emissions， and farmer income， and it can further offer technical advice to farmers for selecting control measures. The case study indicates that the single or integrated application of irrigation area adjustment， irrigation method modification， and agronomic practices is essential for the coordinated management of ET/EC/ES objectives in the irrigation area. This study illustrates that the proposed farmer-level ET/EC/ES target-coordinated control system for groundwater irrigation areas offers a novel scientific solution for the intricate integrated management of water resources and the water environment in these regions and can be used as a reference for other similar regions of China.

Channels are an essential component of irrigation projects， and the development of channel anti-seepage engineering technology is of great significance for promoting the development of agricultural water conservation and agricultural production in China， as well as ensuring national water and food security. This paper summarizes the development process of channel anti-seepage engineering technology in China， which includes four stages： recovery and initiation， experimental exploration， steady development， and rapid improvement. It elaborates on the current status of channel anti-seepage engineering technology， identifies existing issues in its development， and proposes trends for the future development of this technology. It is believed that the future development of channel anti-seepage technology should be compatible with the construction of modern irrigation districts， coordinated with water ecology and environmental construction， and integrated with the development of new quality productive forces. Research and promotion should actively be conducted in areas such as new anti-seepage materials， prevention and control technologies for frost heaving damage， mechanized construction techniques， and ecological environmental impacts.

To address the demand for full-day water demand forecasting in water supply enterprises， a parameter tuning method for water demand forecasting based on the dual closed-loop control theory and adaptive machine learning is designed and developed. The method innovatively introduces the ratio of daily and 15-minute variation coefficients， and triggers the dual closed-loop control processes to adjust output deviations when the preset error threshold is exceeded. Through the analysis of actual water supply data from a water company in Guangdong Province， the application of this parameter tuning method has achieved a 15% increase in prediction accuracy and approximately a 1.2% improvement in model stability compared to traditional forecasting methods in forecasting daily water supply. These results suggest that the model can effectively enhance the accuracy and stability of water supply forecasting， providing a more precise tool for water supply scheduling and resource management， and holds significant practical application value in the development of urban smart water management.