In the 1990s， the discipline of eco-hydrology was gradually derived. Eco-hydrology mainly studies the coupling mechanism and development law of ecological process and hydrological process. In recent years， water resources shortage， uneven spatial and temporal distribution of water resources， water waste， water pollution and other problems are prominent. It has become an urgent need for the rational allocation of water resources to master the distribution law of water resources with temporal and spatial changes， formulate ecological protection strategies suitable for sustainable development of local ecological environment， and establish watershed management and control mode and water resources development strategy based on water resources carrying capacity. To achieve the above requirements and objectives， eco-hydrological regionalization is the basis， and the objective of eco-hydrological regionalization is to provide a minimum management unit for analysis and evaluation under different ecological systems and hydrological characteristics. Eco-hydrological regionalization is mainly used to study the regional differentiation of eco-hydrological phenomena and reveal the regional distribution law of eco-hydrological phenomena. This paper focuses on the development of ecological regionalization， hydrological regionalization and eco-hydrological regionalization， the construction of ecohydrological regionalization index system， and the methods of eco-hydrological regionalization. The problems existing in the current research are discussed： foreign researches mainly focus on ecological regionalization or hydrological regionalization， but the regionalization considering the coupling relationship between ecology and hydrology is scarce. Although domestic researches on eco-hydrological regionalization have been carried out， they focus on traditional methods such as principal component analysis and clustering method， fixed time period analysis and large and medium spatial scale research. The future research direction and development trend are put forward： optimizing the evaluation index system， integrating multi-source data， improving the accuracy of regionalization method and monitoring the dynamic change of regionalization.

With the continuous development of economy and society， great changes have taken place in the national water intake situation. In order to adapt to the requirements of high-quality development of water resources management in the new situation and respond to the needs of building a smart water digital twin data base， the construction of the national water resources monitoring and measurement system needs to be strengthened. As the main water intake form in China at this stage， it is necessary to study the technical methods to improve its monitoring and measurement capacity. This paper investigates and studies the data of more than 5.5 million water intakes nationwide collected in 2021 by combining field investigation and data collection. From the national and typical provincial levels， the current situation of water intake monitoring and metering is analyzed according to different water intake scales， water intake purposes， water intake projects， monitoring and metering facilities and water transmission type， and the comparison and selection of monitoring and metering facilities， improvement of monitoring accuracy. Technical methods are proposed to improve the stability and durability of monitoring， improve the application of system platform functions， and promote the improvement of pipeline type water intake monitoring and metering capacity. The research shows that： ① The number and distribution of water intakes across the country are significant. The number of water intakes is huge and the spatial distribution is uneven. There are many water intakes in the north， mainly groundwater intakes， and few water intakes in the south， mainly surface water intakes. ②The national water intake monitoring and metering work should be further strengthened. At this stage， the focus should be on improving the pipeline type water intake monitoring and metering capacity. The monitoring and metering methods and facilities used are different due to different conditions such as water intake scale， water intake scene and water intake purpose. The error， environmental adaptability， measurement cost， advantages and disadvantages and unique application scenarios of different monitoring and measurement facilities are quite different. ③ The monitoring and metering lifting of pipeline type water intakes is a comprehensive task. It is necessary to comprehensively improve the monitoring and metering capacity of the water intake from four aspects： metering accuracy， stability and durability， system platform application capability， and the introduction of relevant technical standards. The research findings provide an important basic data reference for comprehensively understanding the current situation of water intake monitoring and metering in China， a technical reference for improving the monitoring and metering capacity of pipeline water intakes， and a technical support for the next step of water intake supervision.

Research on the cross-domain flow pattern of agricultural virtual water can reveal the deeper relationship between trade and regional water shortage， which is of great significance for ensuring food security， optimizing water resources allocation， and promoting high-quality regional development. As the largest urban agglomerations in China， the Yangtze River Delta has frequent internal resource flows and close agricultural trade with other domestic regions. But it also faces risks such as water shortage. Taking the Yangtze River Delta as an example， this paper constructs the input-output model of water resources expansion to calculate the agricultural virtual water flow momentum， and combined with the virtual water balance state and water resources pressure state， the influence of the virtual water flow relationship driven by agricultural products trade in domestic urban agglomeration is explored. The results show that： from the state of regional water resources， the pressure state of water resources in the Yangtze River Delta is relatively high， and the water use contradiction is prominent. The state of virtual water balance is highly dependent on the inflow of virtual water from outside the region. From the perspective of time， since the new normal of economy， the Yangtze River Delta has always shown a state of net agricultural virtual water input， with the input of virtual water resources on the whole showing an upward trend， while the self-sufficiency rate of virtual water shows a downward trend and then an upward trend. Before and after the structural reform of agricultural supply side， the flow structure of agricultural virtual water in the Yangtze River Delta has changed， and Jiangsu Province has replaced Anhui Province as the most important source of virtual water in Shanghai. From the spatial dimension， the virtual water flow in the Yangtze River Delta presents a chain structure of “Anhui-Jiangsu-Zhejiang-Shanghai”. The Yangtze River Delta and the rest of the country show a virtual water flow feature of “one-way flow in the north and two-way interaction in the south”. Finally， based on the perspective of virtual water strategy implementation， relevant policy suggestions are put forward from the perspectives of guiding the orderly flow of resource elements within the region， perfecting the value realization mechanism of ecological products and improving the inter-regional trade structure， so as to provide references for adjusting and optimizing the regional agricultural production and trade pattern and promoting the construction of urban agglomeration in harmony between people and water.

Based on deep learning， precipitation prediction has been a hot topic in hydrological research in recent years. Monthly precipitation data is a typical small sample data that cannot meet the demands of deep learning for large datasets. Therefore， this paper proposes an improved method for predicting monthly precipitation using a Long Short-term Memory Network （LSTM） by integrating the ideas of signal decomposition and boundary correction. First， to address the “end effect” of sequence decomposition， this paper uses the waveform feature matching extension method to expand the boundaries of the original sequence. Then， the original sequence is decomposed twice by using Extreme-point Symmetric Mode Decomposition （ESMD） and Variational Mode Decomposition （VMD）. ESMD is used to extract different sorts of scale information of the monthly precipitation sequence， obtaining several model components with decreasing frequencies and one residual component. After cutting off the most severe extension parts that “pollute” the internal data of each sub-sequence， VMD further smooths the high-frequency components. Finally， LSTM is applied to each sub-sequence for prediction， and the predicted results are reconstructed to obtain the final prediction. The monthly precipitation in Badong County， Hubei Province is selected as an example for verification. Through model comparison analysis， the results show that compared to traditional single SVM and LSTM models， the prediction model combining signal decomposition algorithm has more advantages in monthly precipitation prediction； The method of boundary correction is incorporated into the combined model by using the ESMD algorithm improves the overall prediction accuracy of the model. The prediction effect of high-frequency components is a key factor determining the accuracy of combined model prediction. The method proposed in this paper not only performs the best on the selected evaluation indicators but also significantly improves the fitting effect of extreme data points. In particular， even when facing a small sample dataset， the Nash-Sutcliffe Efficiency coefficient （NSE） of monthly precipitation prediction can reach 0.960 0 by using this model.

Urban water resources planning and management is a key link to ensure sustainable urban development and satisfy the basic needs of residents. Short-term water demand forecasting is the basis of urban water resources planning and management. As temperature， precipitation and evaporation vary significantly with the seasons， they directly affect the peak of water consumption in different seasons. As a result， the traditional fixed time slot prediction based on time series algorithm cannot adapt to the change of time slot， so the prediction accuracy cannot be guaranteed. Aiming at the problem of low accuracy of fixed time slot prediction， this paper studies a dual-time scale urban short-term water demand prediction model based on 24 h time resolution in four seasons and 15 min time resolution in summer. This model uses Anomaly-Transformer model to detect outliers and calibrate outliers by piecewise curve fitting. Principal component analysis is used to analyze and extract the main components of urban short-term water demand factors. In the standard model analysis of AutoML， three models with the best effects are selected as the base learner of the stacking model combined with the long-term and short-term memory network （LSTM， long-term and short-term memory） and the neural prophet model （NP） after hyperparametric optimization of Optune framework predict the short-term water demand of the city on both time scales， and add the safety net mechanism to ensure the accuracy of the LSTM-NeuralProphet model. Compared with other models （LSTM model， Neural Prophet model， BP neural network model）， the average absolute error of LSTM-Neural Prophet model is reduced by 0.18%~1.96% on the data set with 24 h time resolution of four seasons. In the summer 15 min time resolution data set， the reduction is 0.45%~11.90%. The experimental results show that the LSTM-Neural Prophet model has a better fitting effect and higher prediction accuracy， and can accurately predict the urban water demand at both time scales， and can be applied to the short-term urban water demand prediction research.

Accurate predictions of monthly streamflow are of great importance for reservoir operation management. The existing approaches for the monthly streamflow predictions can be broadly classified into data-driven and process-based models. Predictive performance of data-driven models is highly sensitive to model structures and input variables. However， most studies focus on comparing model structures， which ignore the relationship between model inputs and monthly streamflows. Despite the growing interest in using sea surface temperature （SST） anomalies over specific areas as predictors in data-driven models for predicting monthly streamflows， spatial distribution patterns and correlation of sea surface temperature have rarely been considered in previous studies. Therefore， this study investigates the role of SST dipole on monthly streamflow prediction and the influence of different combinations of historical streamflow observations， atmospheric indices and SST dipoles on predictive performance. Different multiple linear regression （MLR） models are developed for the twelve months of the year to predict monthly inflows for the Tianyi Reservoir at lead times of 1 to 12 months. Results show that although historical streamflow observations have little value by themselves， they generally improve the predictive performance when used in combination with historical atmospheric indices or with SST dipoles for 1- to 3-month-ahead streamflow predictions. MLR models generally perform better when SST dipoles are included as predictors for monthly streamflow prediction at longer lead times. The largest improvements are found for September and November. For example， compared with using historical streamflow observations and atmospheric indices as predictors， streamflow observations and SST dipoles used as predictors have improved the averaged prediction accuracy by 7.1% and 9.3% for the two months with lead times of 1 to 12 months， respectively.

In recent years，the water level in Poyang Lake has repeatedly reached a record low in dry seasons，which has led to increasingly prominent economic and social development and ecological and environmental protection issues. In order to identify the law of water level changes of Poyang Lake and quantify the degree of contribution of different influencing factors on the changes in the water level of Poyang Lake， this paper uses Mann-Kendall test and polynomial regression analysis methods to quantitatively analyze the change trend of water level of Poyang Lake and its causes. In this paper， Xingzi Station and Hukou Station are taken as the water level and flow representative stations of Poyang Lake respectively， and Jiujiang Station is taken as the representative station of the mainstream of the middle and lower reaches of the Yangtze River. First， the long-term observed data of the Yangtze River Basin and Poyang Lake from 1981 to 2021 are selected for case studies. The main influencing factors of the water level changes of Xingzi Station on the Poyang Lake are identified by correlation analysis. The trend characteristics of the water level of Poyang Lake are analyzed by the Mann-Kendall test method. Finally， the degree of contribution to the changes in the water level of Poyang Lake during the dry season is quantified based on the water volume relationship. The results show that the changes in Poyang Lake′s water level from the perspective of water volume are mainly affected by the total water volume of Jiujiang Station and Hukou Station. In 1981 before the Three Gorges Reservoir was built， the lowest water level of Poyang Lake had shown a significant downward trend. After the reservoir was built， the lowest water level of Poyang Lake in the normal storage period rose by 0.44 m compared with the initial storage period， indicating that the water supply regulation of the Three Gorges Reservoir in the dry season alleviated the downward trend of the water level of Poyang Lake in the dry season to some extent. Impoundment of the Three Gorges Project is not a key factor affecting the decrease in water level in the dry season of Poyang Lake， with a contribution of 35.4%， but is mainly affected by the comprehensive factors such as decreased water and cutting under the river bed， with a contribution of 64.6%. In addition， the water supplement of the Three Gorges Reservoir has a positive effect on the increase in water level of Poyang Lake in the dry season， with a contribution of 20%， and the contribution of factors such as the cutting of the riverbed and the reduction of other incoming water is -120%. The study can provide scientific basis and guidance for formulating countermeasures for low and dry water levels of Poyang Lake in the dry season and improving water resources and water environment carrying capacity of the lake area.

The effective flood storage volume of flood storage and detention area is the real capability of occupying flood， which is a fundamental basis when formulating and optimizing real-time the flood dispatching plan in flood storage and detention area. The dispatch of inland river flood will occupy the flood storage volume of lakes， polders and swales in the flood storage and detention area， reducing the effective flood storage volume. This paper selects the flood storage and detention area of Longsai Lake， Hanbei River as an example， calculates and analyzes the flood storage volume and its variation characteristics of lakes， polders and swales occupied by the inland river flood dispatching at different frequencies as well as the change rule of the effective flood storage volume after dispatching inland river flood and its influence. The results show that： ① When there are lakes， polders and swales in a flood storage and detention area， the flood storage volume of lakes occupied by the dispatching of inland river flood is significantly greater than those of polders and swales， and the greater the inland river flood， the greater the difference in flood storage volume occupied between lakes versus polders and swales. When the 5-year to 50-year occurrence flood happens in the inland river of the Longsai Lake flood storage and detention area， the flood storage volume occupied by lakes are 97.9%~98.1% in all dispatching volume. ② The reduction of the effective flood storage volume in flood storage and detention area caused by inland river flood dispatching changes with the frequency of inland river flood. The greater the flood in the inland river， the more significant the reduction of effective flood storage volume in flood storage and detention area. When the 50-year occurrence flood happens in the inland river of the Longsai Lake flood storage and detention area， the effective flood storage volume decreases by about 13.5%， and when the 5-year occurrence flood happens， the effective flood storage volume decreases by 7.81%. ③ When the inland river flood occurs and is likely to encounter the flood of the mainstream， the reduction of effective flood storage volume will influence the flood dispatching plan obviously， and the effective flood storage volume of the flood storage and detention area shall be calculated and determined in real time according to the incoming flow， and the dispatching plan shall be optimized or adjusted， the personnel and property shall be transferred in advance.

Aiming at the problems of weak evaluation methods and unclear driving mechanism of regional flood disaster resilience， an evaluation index system of flood disaster resilience from natural， economic， social and technical dimensions was constructed， and Projection Pursuit Model Based on Bald Eagle Search Optimization Algorithm（BES-PP）was established. Based on this， the BES-PP model was used to evaluate the flood disaster resilience of Jiamusi City from 2003 to 2020. The results show that the resilience level of Jiamusi city can be divided into three stages： the first stage （2003-2006） resilience rose steadily but at a low level； the second stage （2007-2013） resilience fluctuated obviously； the third stage （2014-2020） resilience rose rapidly and finally reached a high level. In order to analyze the driving mechanism， the BES-PP model was used to analyze the weights of each index. The results showed that the natural rights-protecting weights of economic peacekeeping reached 1.211 68 and 0.932 42， respectively， and their average weights reached 0.302 92 and 0.310 81， which were much higher than the technical dimensions of social peacekeeping. It shows that the index of natural and economic dimensions has a high degree of influence on the resilience of flood disaster and the important role of natural and economic factors in avoiding flood disaster should be paid attention to. In order to verify the performance of the BES-PP model， Projection Pursuit Model Based on Slime Mould Algorithm（SMA-PP）and Projection Pursuit Model Based on Whale Optimization Algorithm （WOA-PP） are introduced for comparative analysis. The results show that the BES-PP model has obvious advantages in performance. In addition， the evaluation results of BES-PP， SMA-PP and WOA-PP were analyzed by using the serial number sum theory， and it was found that the evaluation results of the BES-PP model were more reasonable. The research results provide a scientific basis for the improvement of disaster prevention and reduction capacity of Jiamusi city， and also provide some valuable information for the assessment of disaster resilience.

Agriculture is an important part of the global ecosystem carbon cycle， which is greatly affected by drought. Therefore， understanding the impact of drought on the carbon sink intensity of agro-ecosystems helps to figure out the change regular of agro-ecosystem carbon cycle and provide a theoretical basis for realizing the control of carbon emissions. In this paper， the net ecosystem exchange （NEE） of winter wheat-summer maize rotation system in North China Plains is simulated by vegetation photosynthesis and respiration model （VPRM）， and Drought Severity Index （DSI） is calculated based on evapotranspiration and normalized vegetation index to evaluate the agricultural drought intensity. The spatiotemporal response of NEE to agricultural drought is also assessed by using geographic detectors and de-trended analysis. The results show that the agricultural drought intensity in the northern part of North China Plains is more than that in the southern part of North China Plains during the growth period of winter wheat， and the agricultural drought intensity gradually decreases with the development of winter wheat. During the growth period of summer maize， North China Plains enters the rainy season and is generally wet. The carbon sequestration capacity of cropland ecosystem decreases with the increase in agricultural drought intensity， and the sensitivity of NEE of cropland ecosystem to agricultural drought is greater in the middle growth stage of winter wheat/summer maize than in the early and late growth stages. The spatial variability of agricultural drought has the largest explanatory power for NEE of winter wheat in March （q=0.681）. The explanatory power for NEE of summer maize is the highest in August （q=0.792）. With the increase in agricultural drought intensity， wheat and maize fields change from strong carbon sink to weak carbon sink if grain carbon content is not considered， and finally change to carbon source if grain carbon content is considered.

The large-scale vortex formed in the Savonius hydro turbine wake field tends to act on the back of the blade， increasing the negative torque of the rotor， resulting in a decrease in its power coefficient. In this paper， three rectifier grids of different structures are arranged at 0.8D （D is the diameter of the wheel）， 1.2D and 1.6D from the rotation center of the S wheel， and the influence of the rectifier grid on the power characteristics and inflow field of the wheel is studied by using CFX for numerical simulation calculation and analysis. The results show that when the leaf tip speed ratio r is 0.91， the torque coefficient and power coefficient of the four blade rectifier grids are set at 1.2D from the rotation center of the S wheel. The values 0.273 and 0.192 for the largest torque and power coefficient， which are 2.5% and 2.3% more than the torque coefficient and power coefficient without rectifier grid， respectively， it is also found that after the fairing grid is set behind the rotor， the vortex scale in the wake field is significantly reduced compared with that without the rectifier grid. The fluid velocity distribution after the rotor becomes uniform， which reduces the flow loss caused by the secondary flow on the one hand， and effectively reduces the pressure pulsation in the wake field on the other hand.

Hydraulic ECC materials are characterized by large deformation ability， strong crack resistance and good self-healing capacity. In this paper， two strength grades of hydraulic ECC materials with water-binder ratio of 0.35 and 0.25 are prepared， and the influence of artificial sand grading on compressive strength and splitting tensile strength of hydraulic ECC materials is studied. Moreover， key factors affecting the self-healing capacity of hydraulic ECC materials are analyzed by using compressive strength ratio as evaluation index. Experimental results reveal that artificial sand grading has a significant effect on the workability of hydraulic ECC materials， while there is no notable correlation between artificial sand grading and compressive strength， and self-healing capacity and while splitting tensile strength increases slightly with the decrease in artificial grading. Hydraulic ECC material has good strength growth characteristics and self-healing capacity， and the compressive strength at 90 d age can be 30%~40% more than that of 28 d age. It is worth noting that hydraulic ECC materials strength after healing is possibly more than that of undamaged sample in early stage.

In order to meet the needs of the society for public services， the government actively explores the purchase of public services from social forces. With the continuous promotion and cultivation of small and medium-sized water conservancy project operation and maintenance service market by the government， the subject of undertaking has gradually become diversified， and how to select the contractor is crucial. However， there is no complete method for the government to select the contractor of small and medium-sized water conservancy project operation and maintenance service. Combined with the current situation of water conservancy public service purchase in China and the characteristics of operation and maintenance services for small and medium-sized water conservancy projects， a two-stage selection mechanism for small and medium-sized water conservancy project operation and maintenance service providers is proposed. The indicator system for contractor selection is constructed respectively， and the VIKOR evaluation model is established. Finally， the scientific and rational selection mechanism of the contractor is proved with examples， providing a reference for the selection of water conservancy public service providers.

Exogenous silicon is widely applied to soils to alleviate the soil cadmium contamination. The effect of silicon on the translocation and transformation of cadmium in plants and soils has been thoroughly studied， but the influence of silicon on soil water movement has rarely been reported. Hence， an experiment is conducted to investigate the influence and mechanism of silicon （0， 200， 400 kg/hm²）， cadmium （0， 2.5 and 5 mg/kg） and their reactions on the soil water characteristic curve （SWCC）. The group of soil with no addition of silicon and cadmium （0 kg/hm²， 0 mg/kg） is denoted as CK for comparison. The SWCCs of soils are measured by pressure plate extractor， and pH， zeta potential. Field Emission Scanning Electron Microscopy （FESEM） are performed for the soil samples. After that， three models including Brooks-Core （BC） model， Van Genuchten （VG） model， and Dual-porosity （DP） model are used to fit the experiment data. The results show that ① in comparison with the CK， cadmium has no influence on the SWCCs， the right-skewed SWCCs of soils with silicon application indicate that more water is held in soils， whereas the left-skewed SWCCs of cadmium-contaminated soils with silicon application indicate a reduction in the water holding capacity of soils within the suction range of 710~1 200 kPa. ② Compared to CK， cadmium has no influence on the soil pore distribution. Silicon application in both no cadmium-contaminated and cadmium-contaminated soils increase the proportion of soil macropores （equivalent pore size of 0.002 14~0.002 50 mm）， whereas there is no influence on the small pores （equivalent pore size of 0.000 49~0.002 14 mm）. ③ The images of FESEM illustrate that there is no difference between the CK and the cadmium-contaminated soils， whereas the soil particles are more clustered after silicon application in comparison with CK. ④ Silicon application can significantly increase the pH value and the absolute value of soil zeta potential. The high absolute value of soil zeta potential is of benefit to disperse the soil colloidal particles， which goes against the formation of soil micro-aggregates. However， the silicic acid gel is formed after silicon application can promote the cementation of soil micro-aggregates and thus increase the proportion of large pores in the soil and improved soil water holding in the low suction range. van der Waals force might be weakened due to the formation of silicon-cadmium complex after the application of silicon in cadmium-contaminated soil， which reduces water holding ability of soils within the high suction range. ⑤ Compared with BC model and VG model， DP model can better describe the influence of silicon and cadmium on soil water characteristic curve， and the influence of silicon application on soil hydraulic characteristics can be quantitatively expressed by adjusting saturated and residual water content of soil water characteristic curve.

During the large-flow water transmission of the middle line of the South-to-North Water Diversion Project， some aqueducts experienced varying degrees of water level fluctuations， which had a certain impact on safety scheduling， especially the shorter the aqueduct body， the more obvious the phenomenon. In this paper， the RNG k-ε model and Tru-VOF method are used to establish several sets of full three-dimensional numerical models with different tank lengths for typical aqueducts， and explore the influence of tank length parameters on water level fluctuations. The results show that the Carmen vortex street formed at the exit of the tail pier downstream of the aqueduct is the source of fluctuations， and the vortex causes local water blockage， which in turn generates fluctuations to be transmitted upstream. With the increase in the length of the tank， the fluctuation transfer energy is gradually dissipated， the maximum flow velocity and the amplitude of water level fluctuation continue to decrease， and when the length exceeds 800 m， the water level fluctuation energy is basically dissipated. The results can provide a reference for the smooth scheduling and safe operation of the project.

In order to explore the influence of different types of valves on shutdown characteristics of delivery system， this paper builds a 3D CFD numerical simulation model including centrifugal pump， outlet valves and pipelines with the dynamic mesh and sliding mesh methods. The inner and outer flow characteristics are obtained. The results show that with the same closing law， the shutdown characteristics are similar when equipped with butterfly and ball valves， and has obvious difference in the second half of closing process when equipped with the gate valve. The main reason for the difference is that the gate valve has a weaker shut-off ability compared with butterfly and ball valves. Shorter closing time would make the timing corresponding to reverse extreme values to move backward， and therefore the difference between reverse extreme values would be larger when equipped with different types of valves. This study reveals the differences of shutdown characteristics with different types of valves.

It is a common arrangement for pump station diversion from the middle of long free-flow tunnel or channel. The hydraulic transient calculation usually involves the coupling of pressure flow and free flow. Taking a typical pump station as an example， this paper presents a method to solve the pressure flow and free flow as well as the control strategies and hydraulic characteristics on accident power off， normal start， and normal stop. The free and pressure flow can adopt long and short time steps. During a long time step， the water level of the connection point is assumed constant， and the hydraulic transient of pressure flow is determined. The discharge of the connection point is then used in the calculation of free flow. The gate in the studied case should be considered as not merely a cut-off unit but a surge tank. The result serves as a reference for the hydraulic transient calculation of other similar projects.

In order to explore the water movement characteristics of ball valve and DN63 tee combined deformation variant， this paper uses Fluent software to numerically calculate the combined deformation variant based on the Realizable k-ε turbulence model， and analyzes the effect of valve opening， Reynolds number and splitting ratio on the comprehensive resistance coefficient of combined deformation variant. The results show that when the flow velocity and splitting ratio are certain， the opening degree of the ball valve has a significant effect on the comprehensive loss of the combined deformation parts， with the increase in the opening degree， the flow velocity gradient in the spool decreases， and the vortex area is formed before and after the valve decreases. After the Reynolds number is more than 1.8×10⁵， it tends to be stable. The most important factor causing the integrated local loss of the combined deformation is the size of the valve opening， followed by the variation of the shunt ratio and Reynolds number.

It is inevitable to develop strata through cracks in the site selection of long-distance water transfer projects， and the cracks in the strata have an important effect on the see-through field of slope， which may induce the leakage failure of channels. In Laizhou and partial drainage period of Jiaodong Water Diversion Project as the research object， based on the measured fracture distribution of samples and the Monte Carlo Method to generate the random distribution of fracture network. Finite element numerical calculation software COMSOL model based on pore and fracture model are used to carry out the different rainfall channel fractured rock slope under the condition of seepage analysis. The results show that the migration speed of the wetting peak in the fracture model is faster than that in the pore model， and the pore water is easy to contact the groundwater in advance， resulting in the rise of the groundwater level at the slope location. Under the same rainfall intensity and groundwater level， the water head value at the foot of the channel slope of the crack model is more than that of the pore model， which is more likely to cause the failure of the channel lining plate. Under the same rainfall condition， the existence of cracks makes the failure time of the lining plate advance， and also expands the failure range. The greater the rainfall intensity， the greater the failure area.

As an important propaganda position of China's water conservancy， the core journals of water conservancy play an important role in promoting the development of China's water conservancy science and technology. In order to further enhance the influence of water conservancy journals in China， this study takes the journal “China Rural Water and Hydropower” as an example， combined with the bibliometric indicators of the journals in the past five years， this paper puts forward the following measures： ① closely track major national water conservancy research projects； ② Strengthen the solicitation of research papers on macro policies； ③ Strengthen the solicitation of technical application papers and improve the quality of engineering technology papers； ④ Fully utilize the Council platform to expand the influence of journals； ⑤ Give full play to the role of the editorial board in running the journal.

In order to study the river regime evolution of the braided reach in Lower Yellow River after the operation of the Xiaolangdi Reservoir， the Landsat satellite remote sensing images of the braided reach in Lower Yellow River during the past 20 years from 2001 to 2020 are selected， and the edge extraction algorithm is used based on ARCGIS and ENVI software to extract water edge and correct the normalized differences. The water body index method （MNDWI） is used to extract the water body and analyze the characteristic indicators such as the water surface width of the river channel during the flood season， the position of the mainstream after the flood season， and the number of central banks after the flood season. The results show that： ①After the operation of Xiaolangdi Reservoir， after 20 years of dredging adjustment， the river conditions in the braided reach in Lower Yellow River have been significantly improved during the flood season， and the mainstream has basically returned.②There is no obvious change in the river shape of this reach， and the width of the water surface increases and decreases with the amount of water during the flood season， and generally widens year by year. However， the width of the water surface of the Jiahetan-Gaocun section is relatively stable due to the control of the river channel improvement project. ③Using the MNDWI method to intelligently extract the water body， it is found that the swing of the mainstream presents three rules： ①The position of the mainstream is basically unchanged. ②Mainstream position moves in the same direction. ③ Mainstream locations are migratory. ④The number of the mid-channel beaches is negatively correlated with the water volume， generally decreasing year by year from 2001 to 2007， reaching a minimum of 13 in 2007， increasing year by year from 2007 to 2015， reaching a maximum of 58 in 2015， and decreasing year by year from 2015 to 2020， and at the same time， the location of the river-shaped abrupt change in the channel will also change. The adjustment of river regime will change the effectiveness of the river improvement project， and will also affect the production and life of the people in the beach area. Therefore， it is necessary to strengthen the monitoring of the river regime in the wandering section of the Lower Yellow River and pay enough attention to the changes of the heart beach to enhance the understanding of the law of river situation adjustment and the evolution of the heart beach in the Lower Yellow River.

To effectively eliminate the deposition effect of sediment on the reservoir and avoid its secondary pollution to the water body， this paper proposes a new philosophy of the integrated dredging of pulsed water jets and air lift pumps to boost the dredging performance of the air lift pump， which can be realized by innovating a new structure of a spiral air lift pump. The influence of the number of nozzles and their ways of distribution on the dredging characteristics of the air lift pump is studied， and the developed model is used in engineering practice. The results show that the introduction of the water jet nozzle exerts little effect on the water volume J_L of the air lift pumping system but can greatly increase discharge amount of solid J_S . The nozzle plays the role of relieving the static pressure on the bottom， so the bottom flow field pulsates， the apparent flow rate of the solid is greatly improved， and the particles are poised to move. However， the nozzle needs to be distributed disproportionately but not too “exaggeratedly”， otherwise it will easily trigger dynamic pressure， resulting in reduced lifting performance. Meanwhile， the immersion rate γ can produce a strong influence on the lifting performance. With the increase in immersion rate γ， the amount of J_L and J_S are greatly improved， and especially the peak of J_S is as much as 10 times that under the working condition without nozzle. Based on the laboratory experiments and field tests， it can be verified that the greater the immersion rate of the air lift pump， the higher the dredging efficiency， which is especially suitable for deep-water dredging and is also consistent with the theory.

In order to solve the problem of sediment accumulation in the diversion canal， which adversely affects the water supply system， this paper designs a diversion and sand discharge system at the head of the canal to improve the efficiency of water use. According to the measured data of a section of the Yellow River Ningxia， a two-dimensional numerical simulation is used to construct a two-dimensional hydrodynamic model and a sediment model based on MIKE 21 for a section of the Yellow River Ningxia to simulate the water diversion at the head of the canal under two different working conditions. The results of the study show that the diversion channel changes the equilibrium of the hydrodynamic elements of the river， direct diversion canal （case 1） flow dynamics axis has oscillated 46.6m towards the concave bank， the average sand content of the channel is 0.6 kg/m³ and the maximum sand content is 0.89 kg/m³； the axis of flow dynamics in the sand reduction diversion channel （case 2） has oscillated 62.6 m towards the concave bank， the flow velocity at the head of the channel is in the range of 0.2~0.4 m/s， the average sand content of the channel is 0.2 kg/m³ and the maximum sand content is 0.6 kg/m³. Therefore， the design of the head of case 2 can improve the sediment deposition problem of the diversion canal and enhance the durability of the water intake system.

Controlling the outlet flow rate at the lower boundary of a river can alter the flow rate and direction of the water body， leading to an improvement in the water quality of the river， the improvement effect is related to the scale of diversion and drainage， the layout of the outlet， etc. Scientific and rational allocation of water resources is the core of sustainable water resources use. This paper presents a case study of the river network area of Jiangbei Zhenhai Plains， Ningbo， for example， and selects the simulation period from October 1 to November 1， 2022， NH₃-N as an indicator for the main pollutant， construction of a one dimensional non-constant flow dynamics MIKE11 water quality and water quantity coupling model， taking into account the outflow capacity of the outflow pump station and maintains the minimum water consumption in the basin. The study sets up 28 outflow scenarios with outflow flow rates of 9，18，24 and 36 m³/s through the combination of three outflow opening and closing arrangements. This study aims to simulate the impact of boundary outlet flows on water velocity in various scenarios using a coupled water quality and water quantity model， and analysis of water quality change characteristics. The results show that： ①The higher the outlet flow of the basin， the more significant the increase in the flow velocity of the watershed， comprehensive hydrodynamic and water quality factors， the outflow of 18m³/s can better improve the hydrodynamic conditions and water quality of the river. However， if the flow rate increases to 24 or 36 m³/s and only one or two outlets are opened， the river has the risk of overflow. Therefore， opening more outlets is recommended to ensure flood safety； ② the optimal solution after simulation makes the average flow rate of the basin reach 0.056 m/s， the average concentration of NH₃-N decreases to 1.660 mg/L， the water quality improvement rate reaches 17.0%， the water quality condition of the river can be improved from poor V to IV or V water standard， the results provide a reference basis for improving the hydrodynamic water quality of the river.

The Tesla valve has a special structural form that can guide the flow entering from the reverse port into two sets of straight/curved channels， and dissipate energy through friction and collision at the end of the guide column， greatly weakening the flow velocity in the pool. This unique flow characteristic is very suitable for designing fishways. However， direct applying the original structure of Tesla valves as a fishway has been proven to have significant limitations. The original structure of the Tesla valve fishway is optimized in this paper. By adjusting the aspect ratio of the straight/curved channel in the fishway pool， hollowing out the guide column， and increasing the length of the opening end， a new Tesla valve fishway with relatively independent energy dissipation channels and fish upstream channels has been obtained. The hydraulic characteristics parameters of the optimized Tesla valve fishway are compared with the original structure using numerical simulation， with a focus on analyzing the flow velocity variation， flow field， and turbulent energy distribution of the new Tesla valve fishway. The results show that the new Tesla valve fishway has significant advantages compared to the original structure. While maintaining the same energy dissipation efficiency， it effectively improves the flow pattern in the pool， and the overall flow velocity and turbulent kinetic energy are smaller than the original structure. The new structure significantly increases the proportion of rest areas. When the pool bottom slope gradient from 1% to 3%， the proportion of rest areas in the original Tesla valve fishway is 8.5% to 1.2%， while the proportion of rest areas in the new Tesla valve fishway is 44.7% to 25.8%， increasing the possibility of successful fish upstream migration. The flow velocity and turbulent kinetic energy of the new structure increase with the increase of the bottom slope gradient， but the flow velocity remains low in the fish upstream channels， while the high flow velocity mainly occurs in the energy dissipation passage. The maximum flow rate increase rate in the energy dissipation channel of the first two stages of the pool is relatively high， while after the third stage of the pool， the increase rate tends to slow down. The overall turbulent kinetic energy in the fish upstream channels is relatively low. When the bottom slope gradient is less than 2.5%， the upstream conditions and economy of the fishway are better.

The influence of different vegetations widely habituating on the floodplain of natural rivers on the hydrodynamic characteristics of compound channel has always been concerned. This study has established a numerical model of riparian vegetation flow of compound channel based on Delft 3D software， and adopted the diameter， height and density of vegetation as control parameters， to investigate the influence of these parameters on the longitudinal water surface slope， lateral profile of depth-averaged longitudinal velocity， and the ratio of difference of velocities in main channel and flood plain to the average velocity of whole cross section. Research indicate that the increase in diameter， depth and density of vegetation changes the lateral profile of longitudinal velocity significantly. The ratio of difference velocity and the water surface slope are correlated with the diameter of vegetation quadratic， with the height of vegetation linearly， with the density of vegetation logarithmically. The difference between water surface slopes of main channel and flood plain increase as long as the increase in diameter， height and density of vegetation； and the maximum velocity in the main channel is shifted due to the imbalance distribution of vegetation.

In view of the problems of high energy consumption， poor ecological restoration and rational utilization of waste concrete in the practical application of acid mine wastewater treatment methods.Based on the water purification characteristics of pervious concrete， waste concrete， cement and other materials are used to develop water purification reclaimed aggregate pervious concrete （ZSCR）， combined with diatomite and swelling. The performance and practical application prospect of different ZSCR were studied by modifying the clay and red mud. The recycled aggregate and ore were analyzed by XRD， SEM and other testing methods，Effect of material admixture on its water purification performance. The results show that： compared with ordinary pervious concrete， recycled aggregate has less influence on the water purification performance of pervious concrete.The water purification performance of ZSCR was obviously enhanced after the modification of the admixture. The addition of diatomite and other materials improved the pore structure of the specimen and produced a lot in the gel layer.The unhydrated mineral phase gel particles enhanced the adsorption performance of ZSCR to heavy metal pollutants. When the hydraulic retention time is 12 h and the red mud content is 30%， the red mud reclaimed aggregate pervious concrete can effectively intercept heavy metal ions in surface water of mining area， it can be used as reaction medium in water ecological restoration technology such as constructed wetland and biological filter to treat acid mine wastewater.

To investigate the factors affecting the performance of the 3-blade undershot waterwheel， this paper uses VOF model to simulate the unpressurized flow in the open channel， and the waterwheel with different interlacing angles （0°， 20°， 40°， 60°） of adjacent blades is simulated non-constantly based on the SST k-ω turbulence model， PISO algorithm and slip-grid rotation model. The results show that when the interlacing angle of adjacent blades is 0°， the corresponding waterwheel has the widest and highest efficiency， and the pressure in the front and rear areas of the impeller is basically symmetrical distribution. As the interlacing angle increases， the difference between the front and rear pressure distribution gradually becomes larger. Under the same working condition， the average value of waterwheel torque for one cycle of rotation is 60°， 40°， 20° and 0° in the order of small to large， but the instability also increases in order. In addition， the efficiency of the waterwheel shows a increasing and then decreasing trend with the increase in the blade tip speed ratio； the fluctuation of torque decreases with the decrease in the blade tip speed ratio.

In view of the fact that the additional mass method cannot truly reflect the influence of hydrodynamic pressure in the complex structure of water surrounded by four sides of the intake tower， this paper discusses the coupling effect between the intake tower and the reservoir water based on the acoustic medium theory through the finite element model of the reservoir water-intake tower system established by ABAQUS. The results show that compared with the additional mass method， the natural vibration frequency of the tower-water model based on acoustic element increases， the hydrodynamic pressure decreases， the total displacement of the top of the water intake tower decreases by 66.77%， the acceleration decreases by 10.67%， the maximum tensile stress of the water intake tower decreases by 19.92%， the compressive stress decreases by 21.11%， and the damage area and degree of the water intake tower decrease. The safety of the water intake tower has improved. Therefore， the acoustic unit model has certain accuracy and applicability in the actual engineering design， and provides a new idea for the study of the dynamic water pressure of the water intake tower.

Hydropower development is an important strategic measure for the reform of our country’s energy supply side structure， but its development often brings a large number of population migrations. Whether the resettlement funds can be used to properly resettle the reservoir resettlement is related to the sustainable development of the region and the harmony and stability of the society. The use of resettlement funds at this stage is mainly based on compensation standards and experience， without considering the efficiency of fund use. This paper introduces the principles of market economy， and considers the use of immigration funds as an investment from the perspective of immigration fund planners. According to our country’s current land acquisition compensation resettlement policy， the use of funds is divided into land acquisition compensation， resettlement and follow-up livelihood assistance， and a judgment matrix is constructed according to the benefits of the resettlers to quantify the benefits and risks of different investment directions. On the premise that the three types of investment can meet the minimum needs of immigrants， the Sharpe ratio is used as a measure to calculate the fund use plan with the greatest benefit when the risk level is certain， which provides a new research paradigm for improving the efficiency of the use of immigration funds. Case analysis shows that the investment direction of the resettlement funds of the GB water conservancy project is generally in line with the resettlement wishes， but the follow-up livelihood assistance is low， and the direction of the use of funds should be adjusted to ensure the resettlement’s livelihood recovery and follow-up development.

The minimum pressure at the draft tube inlet of turbine should be controlled above -8 m H₂O in the calculation of transient processes of hydropower station to prevent dangerous water column separation. For the pump-turbine， the magnitude of pressure pulsations is large and their composition is complex. There is no clear answer to which pressure pulsation components should be included in the calculation of the minimum pressure. In this study， a pump-turbine model with straight cone draft tube is considered， and different velocity pulsations are applied to the runner inlet to analyze the changing laws of cavitation cavity at the draft tube inlet. It is found that the maximum cavitation cavity volume of the draft tube is related to the inlet velocity pulsation frequency. With the increase in frequency， the cavity volume increases rapidly first and then decreases slowly. The variation period of cavitation cavity is affected by the pressure pulsation frequency and the pressure fluctuation of the draft tube outlet. The possible pressure pulsation frequency at the actual runner inlet has a great influence on the fluctuation of the cavitation cavity at the draft tube， but the resonance effect occurs when frequency is consistent with the frequency of the draft tube vortex. The fluctuation of the water hammer in the draft tube is the fundamental factor of cavity vorticity.

The time-frequency representation of axial orbit proves to be an effective tool for analyzing non-smooth vibration signals， but the traditional time-frequency representation method has low resolution and is not easy to distinguish the feature frequencies with close distribution. To solve this problem， this paper proposes a time-frequency representation of rotor time-varying complex signals. Firstly， a multi-scale wavelet threshold noise reduction algorithm based on empirical model decomposition is used to process the original signal and obtain the noise-reduced rotor vibration signal. Secondly， Euclidean distance is introduced to reconstruct the time-frequency matrix for the signal time-frequency spectrogram， which not only improves the time-frequency aggregation of the signal， but also makes the time-frequency matrix have better polar point coherence to avoid. Finally， the Vold-Kalman filter is used to separate the fundamental frequency and its harmonic components in the time domain signal， and calculate the instantaneous full-spectrum parameters of the harmonic components to construct a high-resolution time-frequency representation of the rotor signal. The effectiveness of the method is verified by analyzing the simulated signal of the rotor system and the rotor misalignment signal.

In view of the characteristics of strong randomness and low direct prediction accuracy of daily power of runoff hydropower stations， this paper uses the Extreme-point Symmetric Mode Decomposition（ESMD）to smooth the power sequence. Combined with the Least-Square Support Vector Machines（LSSVM）， a combined prediction model based on ESMD-LSSVM is established. The daily power time series of a runoff hydropower station in Northwest China in 2020 is selected for example analysis， and compared with the prediction results of single model SVM， LSSVM， BP and combined model ESMD-SVM， ESMD-BP. The results show that：① PACF analysis shows that the feature vectors of each subsequence after ESMD decomposition are different， which reflects the complexity and variability of the daily power of runoff hydropower stations. ②Compared with the single model， the combined model has stronger generalization ability and more accurate prediction of the power mutation point in the time series. ③The daily power of ESMD-LSSVM combined model has good prediction effect， which provides a new method reference for the daily power time series prediction of runoff hydropower station.

Under the background of building a new power system based on new energy， the traditional decentralized small hydropower controller is more and more difficult to meet the construction needs of distributed small hydropower. In this paper， a distributed small hydropower controller based on ARM+DSP dual-core heterogeneous chip AM2732 is developed， which uses ARM to realize small hydropower control management， fast network transmission and integrity certification of transmission information， and uses DSP to realize small hydropower data acquisition and analyze the processing. According to design requirements， this paper introduces the overall design and hardware and software structure of distributed small hydropower controller. In particular， it focuses on the two key technologies of dual-core information exchange and remote communication integrity certification based on national secret algorithm. Finally， the field application of distributed small hydropower controller shows that it not only has good functions of small hydropower regulation and communication， it can also support the development needs of new power grids such as small hydropower micro-grid.

In order to study the effects of water level drop and rainfall on the coastal wading slope in the Three Gorges Reservoir area， this paper takes the Chicken Brain Shell Landslide as an example， and uses the numerical simulation method to analyze the deformation and failure of the Chicken Brain Shell Landslide under the conditions of reservoir water level fall， rainfall and coupling between the two. Firstly， the stability of landslides under different working conditions is calculated by Morgenstern-Prince method in the two-dimensional model， and the three-dimensional landslide model is used to monitor the changes of pore water pressure， stress and displacement of the landslide， so as to analyze the failure mechanism of the waterslide landslide. On this basis， the influence of single indicators of reservoir water level decline rate and rainfall intensity on the stability of landslide is analyzed. The results show that in the two-dimensional calculation， the reservoir water level slowly drops from 175 m to 145 m， and the landslide is the most dangerous when the chicken brain shell is the most dangerous in the event of heavy rainfall in 50 years， and the stability coefficient of the landslide is 1.032， and the landslide is in an unstable state. In the 3D model， the permeability and displacement of the slope body change greatly， in which the reservoir water level slowly decreases from 175 m to 145 m and encountered heavy rainfall in 50 years， the landslide had the maximum displacement， of which the horizontal displacement reached 31.38mm and the vertical displacement is 31.13 mm. The numerical prediction model shows that the displacement of the landslide mainly occurs in the middle and rear part， so when the reservoir water level drops and is accompanied by heavy rainfall， the deformation of the trailing edge of the landslide should be observed. The analysis of single factor shows that when the landslide only adjusts the reservoir water level decline rate， the stability of the landslide decreases as the reservoir water level decline rate increases， and when the water level drop rate is 4.2 m/d， the landslide becomes unstable. The influence of rainfall factors indicates that the greater the rainfall intensity and the longer the rainfall duration， the more likely the landslide becomes unstable， and the landslide stability coefficient reaches 0.968 for 4 days once in 50 years， entering an unstable state， so it is necessary to monitor and warn the landslide during the period of rapid decline of reservoir water level and continuous heavy rainfall.