With the rapid development of urbanization， the quality of the habitat in the Poyang Lake Basin is showing a downward trend， which will threaten the ecological security of the middle and lower reaches of the Yangtze River seriously. Therefore， based on the habitat quality module of the InVEST model， this paper analyzes the impact of land use change， altitude gradient， population distribution， and spatial distribution of regional GDP on the driving factors of Poyang Lake based on the five-phase land use change data in the Poyang Lake basin from 1980 to 2018. The impact of the watershed’s habitat quality and temporal and spatial characteristics. The results show that ① Overall， the Habitat Quality Index of Poyang Lake Basin from 1980 to 2018 was more than 0.8， but showed a slight downward trend as a whole. The Habitat Quality of Poyang Lake Basin showed that the overall habitat quality was higher in southern Jiangxi and northern Jiangxi. The area is relatively low. Among them， Ganzhou City has the highest habitat quality and Nanchang City has the lowest habitat quality； ② Different land use types in the watershed have large differences in habitat quality. The order of habitat quality index is forestland>water area>grassland> cultivated land>construction land>unused land； ③ The quality of regional habitat is closely related to altitude. The habitat quality index shows a trend of first increasing and then decreasing with the increase in altitude， while altitude is between 600~900 m area average habitat quality is the best； ④ Habitat quality shows an increasing trend with the increase in slope， while the regional habitat quality index with slope more than 18 degrees is the largest， and habitat quality is at an excellent level.⑤ The quality of regional habitat is closely related to population density. With the increase in population density， the quality of regional habitat will go from bad to worse， and the quality of regional habitats with a population density of less than 100 persons/km2 is the best. By analyzing the Poyang Lake Basin， the impact of different driving factors on the quality of the habitat is expected to serve as a reference for the ecological protection of the basin.

In order to study the initiation mechanism of non-equigranular particles on loose soil slope under the runoff-seepage coupling effect， a stability analysis model of particles is constructed based on sliding and rolling mechanical analyses of single particle， and the Navier–Stokes Equation and Brinkman extended Darcy Equation are used to describe slope runoff and seepage respectively. Combined with the continuity equation and stress jump conditions， the concrete expression of the fluid-solid interface velocity is calculated， and stability safety factors of single particle under the runoff-seepage linkage effect is obtained. The results show that stability safety factors of particles are mainly affected by runoff depth on the slope surface， thickness of loose layers， slope gradient， stress jump coefficients， soil internal friction angles， equivalent diameters and volumetric weight of particles， porosity and permeability of loose soil slopes； slope gradients， soil internal friction angles and volumetric weight of particles are sensitive parameters of anti-slide safety factors； slope gradients， volumetric weight of particles， runoff depth on the slope surface and permeability of loose soil slope are sensitive parameters of anti-roll safety factors.

This paper studies the influence of psychological factors and regulations of government behaviors on the willingness and behavior of the public to participate in river and lake governance in the River Chief System， based on the expanded theory of planned behavior and taking 580 questionnaires in the Yangtze River Basin as samples. The results show that the three psychological factors have significant positive effects on public participation willingness. The comprehensive impact path coefficients of psychological factors are attitudes toward the Behavior （0.203）＞Subjective Norm （0.167）＞Perceived Behavior Control （0.103）. The regulations of government behaviors can not only affect the participating behavior indirectly through the willingness to participate， but also affect the participating behavior directly. The total effect of the regulations of government behaviors on the participating behavior is 0.445. The comprehensive impact path coefficient of willingness to participate on participation behavior is 0.467， which is slightly larger than the total effect of regulations of government behaviors on participation behavior. Therefore， the government should regulate its behavior and enhance the information publication system by improving the system design of public participation in the River Chief System， so as to cultivate the positive psychological factors of the public， and then enhance the public participation continuously.

A healthy water cycle is the basic support to regional sustainable development. Relevant researches on the water cycle focuses mainly on large and medium cities， and few focuses on county towns. Thus， to indicate the water cycle health of Guantao county town in North China， the evaluation system including five dimensions （water source， water supply， water use， water drainage and water reuse） and nineteen indicators were concluded， based on the healthy characteristics of urban water cycle. By using this indicator system， the regional water cycle health in the past nine years has been evaluated through comprehensive index method and improved gray-relation-analysis. The results of the two methods are highly consistent and the regional water-cycle health has been improved from sub-health to health； the most healthy dimension is water supply and the followed one is water use； the important indicator affecting regional water-cycle health is groundwater depth variation. These results can provide support for the integrated management of water resources and scientific reference to green and high-quality development in county.

In view of the special requirements that the open channel of South-to-North Water Diversion Project should not stop water and desilt and cannot affect the quality of water conveyance in the process of desilting， a new desilting system that can work stably in dynamic water environment is proposed. In this paper， through the force analysis， calculation and model test of the integral dredging system on water and underwater， the hydraulic characteristics of the dredging system are analyzed， and its stability in the dynamic water environment is verified. The results show that when 200 mm× 200 mm× 8 mm× 12 mm H-beam is selected as the connection truss of the underwater system connecting each dredging bin unit， the self-weight of the whole system （67 557.8 N） is more than the buoyancy of the whole system （50 558.4 N）. The installation of process vacuum suckers on both sides of the dredging system can improve the anti-floating stability safety factor of the dredging system from 1.13 to 1.80. The force on the dredging system under the action of water flow meets the anti-floating stability requirements of the overall dredging warehouse in the hydrodynamic environment. The research results serve as a reference for the anti-floating stability study of water retaining structures such as moving water dredging， river crossing and canals.

In order to study the characteristics of nitrogen and phosphorus export from the mountain rivers in Guizhou Plateau， the Tongzi River， a tributary of the Chishui River， is used to analyze the characteristics of nitrogen and phosphorus export of its water quality and non-point source pollution in the basin， and the export fluxes of nitrogen and phosphorus are estimated. According to the land use types of the basin in 2000， 2010， and 2015， the export coefficient model is used to quantify non-point source nitrogen and phosphorus pollution.The results show that the export fluxes of TN and TP of Tongzi River are 253.78 g/s and 6.43 g/s， which has a greater impact on the nitrogen and phosphorus levels of Chishui River. The results of the export coefficient model show that in the 15 years， the total export load of non-point source pollution TN in the basin dropped from 5 039.90 t/a in 2000，4 729.20 t/a in 2010 to 4 516.84 t/a in 2015， and TP decreases from 161.13 t/a in 2000， 153.29 t/a in 2010 to 146.16 t/a in 2015.From the perspective of land use types， the non-point source pollution of cultivated land TN and TP has shown a significant reduction trend， and its contribution rate also decreases year by year， but the contribution rate of cultivated land to TN and TP is still dominant. From 2010 to 2015， compared with 2000 to 2010， the changes in TN and TP load caused by land type conversion are relatively mild. During these 15 years， the change of cultivated land in the Tongzi River Basin has the greatest impact on the total export load of non-point source nitrogen and phosphorus pollution.

The carrying capacity of water environmental is an important index used to judge the state of sustainable development. It is an inevitable trend to realize the high quality development of the region to promote the coupling between the construction of new urbanization and the carrying capacity of water environment. Based on the panel data of Zhejiang Province from 2011 to 2018， the evaluation system of water environmental carrying capacity and new urbanization is constructed respectively， and the spatial and temporal evolution relationship of coupling coordination level is explored by using coupling coordination degree model. The results show that the coupling coordination degree between water environmental carrying capacity and new urbanization development in Zhejiang Province has increased in general during the research period， and the spatial pattern of “strong in the east and north， weak in the southwest” has been gradually reduced. In order to promote the coordination of water-saving and water-control work and the new urbanization strategy in Zhejiang Province， relevant countermeasures and suggestions are put forward.

Due to its unique topography and landform， the process of rainfall production and confluence in mountainous areas is more complex， and the potential water environment problems should not be underestimated. The selection and establishment of the rainfall runoff prediction model in this area can provide hydrological support and reference for the construction and reconstruction of sponge cities in the future. The SCS-CN model proposed by the Soil Conservation Service of the United States Department of Agriculture is not very applicable regionally， so it is necessary to optimize the parameters in the model to improve prediction accuracy. This paper uses a typical mountain city named Chongqing as an example to select Banan District， an undeveloped area， as the research object. It uses the artificial rainfall simulation experiments for different underlying surface conditions of rainfall runoff series data. Based on sponge urban construction measures， the bare land， permeable shop is designed， and the grass of three methods for land use， three kinds of underlying surface optimization coefficient of the early damage of λ are 0.01， this paper considers the antecedent soil moisture conditions， bare land， permeable pavement. The NSE coefficients of the standard model increased by 9.41%， 16.36%， 5.62% and 2.72%， 5.37%， 4.08% in the optimized parameter models of bare land， permeable brick paving and grassland.

In order to quantitatively characterize the damage characteristics of artificial composite soil caused by scouring in water conservancy projects， through the design of artificial composite soil samples with different consolidation agent ratio and different curing time， the scouring test of 35 m/s velocity is realized in the laboratory. The erosion damage edge of the sample is extracted by image analysis technology， and the fractal dimension calculation based on box counting dimension is realized by MATLAB programming. The results show that with the increase in the content of consolidation agent and curing age， the anti-scouring ability of artificial composite soil is significantly improved. The fractal dimension correlates well with damage characteristics and can be used in practical engineering to determine scour damage.

The digital twin technology is an important means to solve the scientific decision-making problems in smart water conservancy， and can solve the problem of scientific decision-making in the process of leaping from information water to smart water. Based on the digital twin technology of industrial engineering， the paper discusses the understanding of digital twin technology of water conservancy engineering. Then， based on the construction experience of online simulation decision system for hydraulic engineering， the architecture design of digital twin technology for hydraulic engineering and the key problems that need to be paid attention to in the construction process are discussed. Finally， combined with project practice， two typical application scenarios are discussed.

In order to realize the recognition of the Songyuan of shallow groundwater pollution sources and pollution risk research， this paper collects Songyuan 58 groups of water quality data of 2017 by using the piper diagram analysis of groundwater chemical characteristics and factor analysis method. Kriging interpolation method is used to identify the pollution sources and the analysis of the spatial distribution characteristics， and application of carcinogenic risk model to determine the high risk area of pollution factors. The results show that the main hydrochemical types of shallow groundwater in the area are Ca-HCO₃ and CaNa-HCO₃. Five common factors （f ₁~f ₅） are extracted as TDS and nitrate nitrogen， ammonia nitrogen and nitrite nitrogen， iron， fluoride and arsenic as the main controlling factors of shallow groundwater. TDS and nitrate nitrogen （f ₁） is mainly controlled by migration and the combined impact of human activity - enrichment of ammonia nitrogen and nitrite nitrogen （f ₂） effect is mainly controlled by human beings； iron and arsenic （f ₃， f ₅） are mainly controlled by original geological effect； fluoride （f ₄） is mainly controlled by original geological function and the combined impact of migration - enrichment of au. The low plain area in the western part of the study area （the western part of Qian 'an and Changling） is seriously polluted while the water quality in the eastern part is good. Pollution risk research shows that fluoride is the most risky pollution factor in the area， followed by less risky nitrate nitrogen， iron and ammonia nitrogen factors.

In order to quantitatively study the impacts of climate change and human activities on basin-scale flood evolution， the Haihe River Basin is taken as the research object. Based on the underlying surface and climate factors， the hydrologic regionalizations of the Haihe River Basin are divided by principal component analysis and cluster analysis methods. On this basis， Spearman rank correlation coefficient， cross-wavelet transform and wavelet coherence spectrum are used to carry out the correlation analysis between basin-scale flood factors and precipitation factors from the linear and nonlinear perspectives. The double cumulative curve method is used to quantitatively reveal the impacts of climate change and human activities on the flood evolution in the Haihe River Basin. The results show that the Haihe River Basin is divided into five hydrologic regionalizations based on underlying surface and climatic factors. Correlations between the flood peak， the maximum 3-day flood volume and the maximum 3-day rainfall in the second-fifth hydrologic regionalizations are significant. In the high energy region，the second hydrologic regionalization had a 0~8 months’ significant positive correlation between the peak flood， the maximum 3-day flood volume and the maximum 3-day rainfall from 1959 to 1968. There was a 0~5 months’ significant correlation between the flood peak， the maximum 3-day flood volume and the maximum 3-day rainfall in the third hydrologic regionalization from 1960 to 1966. The correlation between the maximum 3-day flood volume and the maximum 3-day rainfall in the fourth hydrological regionalization existed in the period of 13~15 and 3~4 months respectively in 1977-1983 and 1993-1997. There was a significant correlation between the flood peak， the maximum 3-day flood volume and the maximum 3-day rainfall in the fifth hydrologic regionalization in 1955-1967， with 0~6 months as the resonance period. In the low energy region， there were many significant resonance positive cycles between the flood peak， the maximum 3-day flood volume and the maximum 3-day rainfall in the four hydrologic regionalizations， and which showed the correlation was strong. Human activities were the main factors for the sharp decrease in floods in different hydrological regionalizations of Haihe River Basin， and the flood peak in the second hydrologic regionalization was most affected by human activities from 1963 to 1978， which comprehensively reflects the significance of large-scale water conservancy project construction and operation and the implementation of soil and water conservation measures for flood release decrease in Haihe River Basin.

The fractal dimension of river network can reflect the characteristics of its structure and play an important role in the study of hydrology and geomorphology. Taking the Yarlung Zangbo River Basin as the study area， 356 sub-basins with different area scales are extracted. The inflection point method is used to determine the optimal threshold of drainage area which is 1.35 km² and the box dimension of all the sub-basins is obtained based on it. It is found that the box dimension of the Yarlung Zangbo River basin is between 1.14 and 1.17， which is in the initial stage of river geomorphology development. The correlation analysis of box dimension with geomorphic and meteorological features shows that the box dimension of river networks in sub-basins in the Yarlung Zangbo River Basin decreases with the increase in the average slope. The relationship between box dimension and average precipitation of small-scale sub-basins is U-shaped to some extent. As for the large-scale sub-basins， due to the limited samples with various precipitation， the relationship shows a decreasing trend with the increase in average precipitation by and large.

Runoff prediction is the premise of optimal allocation of water resources and plays a very important role in regional water resources management. In order to improve the prediction accuracy of annual runoff in arid regions， Empirical Mode Decomposition （EMD） and Variational Modal Decomposition （Variational Modal Decomposition） methods are used in this paper.VMD is coupled with weighted Markov chains， and Wavelet Domain Denoising （WDD） is introduced to build EMD-MK， EMD-WDD-MK and VMD-MK models. Firstly， the annual runoff data of Mahe River is decomposed into several components， and the high-frequency components decomposed by EMD are denoised. Then， each component is predicted and reconstructed to obtain the predicted value. The prediction accuracy of the three models is analyzed through the four indicators of the qualified rate （QR）， mean absolute error （MAE）， mean relative error （MAPE） and root mean square error （RMSE）. The results show that the EMD-WDD-MK model with wavelet denoising has higher prediction accuracy than EMD-MK and VMD-MK models. The coupling model can provide a scientific basis for river planning and allocation in arid areas.

To effectively deal with the rainstorm and flood disaster in urban areas， a waterlogging model of flood control and drainage is built based on MIKE FLOOD platform， coupling MIKE11， MIKE21 and Mike Urban. Dongshan Lake Industrial Park， a newly built urban area， is selected for simulation. Since there is no survey hydrological data in the park， pipeline flow self-test method is used to analyze the rationality of the simulation results. The results show that the simulation results are in good agreement with the actual situation. According to the simulation results of the model， when there is heavy rainfall， there are multiple overflow points in the study area. The roads in the area also have waterlogging by different degrees， some of pipelines are in a state of pressure flow and many inspection wells overflow， resulting in overloading and inability to meet drainage requirements. Aiming at the problems existing in the park， the waterlogging prevention and control scheme is put forward. Based on Mike Flood， simulation is carried out under the combination layout of low-impact development （LID） measures. After the implementation of the measures， the surface inundation area of the study area is reduced， the depth of ponding is generally reduced， the time of ponding at each ponding point is delayed and the total duration of ponding is reduced； the peak flow at the pipe outlet is significantly reduced， and the peak flow of drainage is delayed. This study provides technical support for disaster prevention in the park and serves as a reference for the construction of similar urban areas.

In order to improve the short-term runoff forecasting performance of Andon River Basin， bagging integrated model， stacking integrated model， GBDT integrated model and AdaBoost integrated model are established. The forecasting effect of each integrated model is compared by correlation coefficient， average absolute error， average relative error， root mean square error， Nash efficiency coefficient and quality rate. The results show that these four integrated models can be used for short-term runoff forecast of Andon River effectively， and bagging integrated model has the best overall performance and the highest stability. In addition， the sensitivity of each integrated model to flood scale is analyzed in detail. The results show that AdaBoost integrated model has better prediction effect for large streamflow， while bagging integrated model and stacking integrated model have better prediction effect for small streamflow. In conclusion， bagging integrated model is the best for short-term runoff forecast in Andon River Basin. This study can provide a scientific guidance for flood forecasting and water resources management in the future.

To quantify the impacts of climate and human activities on the changes in land-surface processes is always a hot topic in hydro-meteorological research， especially for Jiaodong Peninsula （JDP） with water shortages. Based on the Budyko-type Equation and a new separation method， this paper estimates the impacts of climate and parameter n （reflects human activities） on evapotranspiration （ET） and runoff changes during the past 50 years over Chanzhi （CZ）， Tuanwang （TW）， Yinfu （YF） and Zanggezhuang （ZGZ） of the JDP， and lastly identifies the corresponding dominant factors. Results suggest that relative to baseline period of 1961-1980）， the 1980s （1981-1990）， 1990s （1991-2000）， and 2000s （2001-2010） ET all declined at ZGZ， but the ET in each period increased over CZ， TW and YF， of which CZ and YF had the largest increases （~100 mm） in 2000s. Except for ZGZ with the dominant factor of precipitation， the changed ET over the remaining basins exhibited the major contributor of parameter n. For the runoff in each period， the reductions were detected at all the basins， with the largest reductions （<-130 mm） in 1980s. In 1980s， the runoff changes had the dominant factor of parameter n （precipitation） for CZ and YF （TW and ZGZ）. During 1990s and 2000s， the dominant factor of precipitation appeared in ZGZ， but the other basins all showed the major contributor of parameter n.

The rules and regulations for water are a summary of water use practices that adjusts and optimizes the complex relationship between human and water system. With the new situations and requirements of water conservancy in the new era， the top-level design function of the planning for system development of rules and regulations for water is becoming increasingly significant. To investigate the effectiveness and deficiencies of water regulation system development in Hebei Province， the matching degree calculation method based on the sequence of numbers is used to calculate the matching degrees between the average per capita water resources and the number of water regulations in 31 provincial administrative regions， and quantify the matching relationship between the water regulation system development and the water endowments conditions. Hebei Province is chosen as the main research object to analyze the reasons for the formation of the adaptive relationship between the two， and to discuss countermeasures for the water regulation system development based on actual needs. The results show the water laws and regulations in Hebei Province are well matched with its water resources. Based on the calculation results of the matching degree and combined with the effectiveness and demand of the water regulation system development in Hebei Province， this paper will systematically make countermeasure analysis for the water regulation system development in different fields， and provide suggestions and recommendations for the 14th five-year plan for water security in Hebei Province.

A neural network model based on time series decomposition is established， which can mine and predict rainfall time series. ①Taking 480 sets of monthly rainfall data of Huantai County from 1979 to 2018 as an example， the rainfall time series is decomposed into trend term， periodic term， mutation term and random term. ②The cumulative anomaly method， Mann-Kendall trend analysis， Hurst index， characteristic point and other methods are used for trend analysis. The wavelet analysis method is used for periodic analysis. Mann-Kendall mutation test method and Pettitt method are used for mutation analysis； the random items are tested by autocorrelation method and unit root method. ③Taking 432 sets of monthly rainfall time series random terms from 1979 to 2014 as calibration data， 2015 to 2016 as testing data，the NAR and NARX neural network model is established to predict the monthly random items in 2017 to 2018 and compared with the direct prediction results. The results show that： ①The rainfall data of Huantai County from 1979 to 2018 has a slight upward trend， and there will be a slightly decreasing in the future. The first main period is 19 （month）， without obvious mutation.② the error between the predicted and measured monthly rainfall in 2017 to 2018 by NAR neural network was 16.79%.

In order to study the effects of livestock-farm wastewater irrigation on the distribution of labile organic carbon（LOC） and the change of carbon management index（CMI） in different soil layers， lysimeter experiment with two qualities of irrigation （clear water and livestock-farm wastewater） as main factors and three quotas of irrigation （64mm， 76mm and 88mm） as sub- factors is conducted and the contents of soil organic carbon（SOC） and LOC in the soil layer of 0~60cm are analyzed. The results show that the contents of SOC and LOC are the highest in surface soil （0~20 cm） and decreases with the increase in soil depth under six treatments. The contents of SOC in surface soil（0~20 cm） irrigated by livestock-farm wastewater is up to 10.79% higher than that by clear water with the increase in irrigation quota. The content of LOC in surface soil （0~20 cm） irrigated by livestock-farm wastewater increases by 2.94%~43.75% compared with the irrigation of clear water at the same irrigation quota. Moreover， CMI in surface soil （0~20 cm） under the irrigation treatment of livestock-farm wastewater is more than that of clear water over time. Compared with clear water irrigation， livestock-farm wastewater irrigation can enhance the availability of organic carbon in soil by increasing the proportion of LOC to SOC in each soil layer， promote the transformation and supply of soil nutrients， and provide a better soil environment for the growth and development of plants and microorganisms. The research results serve as a reference for the formulation of the irrigation scheme of livestock-farm wastewater.

Taking the radial steel gate of Qiyi Reservoir as the research object， this paper emphasizes the coating thickness and corrosion detection of the gate panel and main beam and support arm， and analyzes the detection results. Combined with the inspection data and design drawings， three-dimensional finite element models of the radial steel gate before and after corrosion are established， and the static performance of the radial steel gate before and after corrosion is calculated， and the influence of different corrosion depths on the static performance of the radial steel gate is analyzed and simulated. The analysis results show that corrosion has a very limited influence on the stress distribution of the radial steel gate panel， main beam and support arm， but it will increase the stress value of the corresponding components. The influence of corrosion on the static performance of steel gate is mainly reflected in the decrease in bearing capacity and the little influence on stiffness. Corrosion in specific parts will weaken the strength of each member of radial steel gate to varying degrees.The deepening of corrosion will accelerate the reduction of the strength of gate members.

The pressure fluctuation experiments of a double suction centrifugal pump before and after flexible material winding were carried out on the pump test platform， and the pressure fluctuaions of the pump suction chamber and volute chamber were tested and analyzed under the operating conditions of low flow rate， design flow rate and large flow rate. The results show that the pressure fluctuation at the unwound side of the suction chamber increases at large flow rate after the flexible material is wound before the other sided inlet of the impeller. At small flow rate and design flow rate， the pressure fluctuations at the positions near the tongue of the suction chamber increase， and the pressure fluctuations at the positions far away from the tongue decrease.With the flexible material winding， the pressure fluctuation at the top of the volute chamber increases significantly at each flow rate， and it increases to 200% as that of no flexible material winding at the large flow rate. The research can provide references for the fault diagnosis of double-suction centrifugal pumps and possess certain theoretical value and practical engineering significance.

The single-crop coefficient method is calculating crop evaporation and transpiration based on evaporation and transpiration of the farmland. It is simple in calculation and requires fewer data. In order to explore the optimal irrigation system of cotton under mulch drip irrigation based on single-crop coefficient method in southern Xinjiang， this paper carries out the experiment in Alaer City in southern Xinjiang from 2019 to 2020. Three levels of irrigation time are set in the experiment. When the difference between daily crop evaporation and transpiration and precipitation reaches 25， 30 and 35 mm， the corresponding irrigation quota is 30， 36 and 42 mm， respectively. A total of 3 schemes are designed， and each scheme is repeated three times to study the effects of different irrigation treatments on soil water change， cotton growth yield and water use efficiency. When the difference between daily crop evaporation and transpiration and precipitation reaches 25 mm， the combination of 30 mm irrigation quota and 11 times of irrigation in growth period can ensure cotton yield and significantly improve water use efficiency， which is suitable for the irrigation management of cotton under mulch drip irrigation in southern Xinjiang， and provides a reference for achieving irrigation automation in the future.

In order to explore the soil water status， water consumption rule and water use efficiency of tomatoes with facilities under different residual film amount conditions， and provide a scientific basis for the establishment of efficient irrigation system and residue film control of tomatoes with facilities. In this study， 6 residual film gradients （0， 200， 400， 600， 800 and 1 200 kg/hm²， 0 kg/hm² as control treatments） are set to determine the plant tomato yield and soil moisture content at different growth stages. The results show that： ① the water content of tomato soil profile in 0~30 cm soil layer without residual film treatment is significantly less than that in 30~60 cm soil layer without significant difference. Under the condition of this experiment， the variation trend of soil moisture content in tomato whole growth period is basically the same between residual film treatment and no residual film treatment. ② Under the conditions of this test， the mixture of residual film in the soil has no significant influence on the water consumption and water consumption intensity of tomatoes at each growth stage. ③ The mixing of residual film in soil would affect the yield and WUE of tomatoes， but the yield and WUE of tomatoes treated with residual film are not significantly different from those treated without residual film. Therefore， to a certain extent， the residual film affects the yield and water use efficiency of the tomato by affecting the water distribution in shallow soil， but the effect of the residual film on the growth of tomato is not significant on the whole.

In order to restore the production capacity of rice fields in the project of raising farmland of Xiajiang Water Conservancy Project， a large scale comprehensive pit simulation test is carried out. Two irrigation methods are set， namely flooded irrigation （F1） and intermittent irrigation （F2）， and four soil improvement methods are set， namely no improvement measure （Y1， CK）， soil improvement agent （Y2）， biological organic fertilizer （Y3）， green manure returning to field and early rice straw etching agent （Y4）， which are combined into eight treatments. The effects of different soil improvement and irrigation methods on yield， water use efficiency and photosynthetic characteristics of double cropping rice are studied. The results show that Y4 treatment can increase the number of grains per ear， yield and leaf area index， and is much more than the other two methods compared with Y1 （CK） treatment under the same irrigation mode， and the water productivity， precipitation utilization rate and irrigation utilization efficiency of Y4 treatment are the highest in the early rice period. Under the same soil improvement mode， F2 treatment is more than F1 treatment in the following indexes： ear number， yield， leaf area index， water productivity and irrigation utilization efficiency. In the late rice period， the photosynthetic index of F2 treatment is more than that of F1 treatment. From the interaction of soil improvement and irrigation， F2Y4 treatment yield， leaf area index， water productivity and irrigation utilization efficiency are the highest. In conclusion， the cultivation mode of F2Y4 can provide technical support for achieving high and stable yield and high water use efficiency of paddy field in the lifting area of Xiajiang water control project.

In order to scientifically evaluate the role of science and technology progress in promoting the development of water conservancy， based on the statistical data related to water conservancy development from 2007 to 2018， the C-D production function and Solow residual value method are used comprehensively to construct the quantity model of comprehensive water conservancy factor input and output relations， the quantitative and qualitative analysis shows that the variation trend of the contribution rate of water conservancy science and technology progress in Henan Province in the past 10 years has been relatively stable and has increased year after year， indicating that scientific and technological progress has an important contribution to the development of water conservancy and economic society. It provides a theoretical basis for evaluating the contribution rate， and has a technical reference for optimizing the structure of water conservancy investment and increasing the proportion of water conservancy science and technology investment.

In order to study the influence of different tongue installation angles on the unsteady characteristics of solid-liquid two-phase flow centrifugal pumps， the full flow numerical simulation of five different tongue installation angle volute centrifugal pumps is carried out by using CFX software and the RNG k-ε turbulence model. The influence of the installation angle of the diaphragm on the internal and external characteristics of the centrifugal pump， pressure pulsation， etc is analyzed. The research results show that increasing the installation angle of the separation tongue appropriately has little effect on the head， but the range of the high-efficiency area of hydraulic efficiency widens and shifts to the large flow condition， and the internal flow of the pump is improved. Under different condition setting angles， the tongue， solid-liquid two-phase centrifugal pump pressure pulsations show periodic variations， and the tongue with increasing setting angle of the pressure pulsation in the helical segments shows a decreasing tendency centrifugal pump.The radial force acting on the diaphragm and the impeller is distributed in the shape of a five-point star petal， and the radial force acting on the diaphragm is much more than the radial force on the impeller. The radial forces acting on the diaphragm tongue and impeller are in the shape of five-point petals， and the radial forces acting on the diaphragm tongue are far more than the radial forces acting on the impeller. Increasing the angle of the diaphragm tongue of the volute will make the radial forces at the diaphragm tongue of the volute increase significantly and evenly.

There are many small hydropower stations in Yunnan and they are distributed in remote areas which bring severe challenges in dispatching operation management especially in many other power resources such as wind power and solar power. In order to solve these problems， it is necessary to introduce intelligence method. A method of interactive multi-phase generation dispatching and planning is designed， which adapts to the new power dispatching model and based on the coordinate analysis of multiple small power resources. Then the ascertainment and computation approach of abandoned water is presented. The results of statistical analysis verify that the utilization of clean energy of small hydro-electricity is popularized significantly.

The free-surface-pressurized flow usually occurs during transient process in the hydropower station with a combination of tailrace tunnel and division tunnel. In this paper， one-dimensional calculation based on virtual slit method and three-dimensional calculation based on VOF model are used to study the surge wave of surge tank， the movement of free-surface-pressurized flow， and the water depth at the junction of tailrace tunnel and division tunnel during the transition process. The results show that the surge period difference between the one-dimensional calculation and the three-dimensional calculation under pressure flow and free-surface-pressurized flow conditions is within 8 s， and the difference under the pressure flow conditions is less than 1s， which shows a good agreement. The top pressure of tailrace tunnel decays periodically with time， and it is zero in the open flow zone， positively correlated with the water depth in a full flow zone. A series of residual airbags occur with a quick movement of free-surface-pressurized. The disruption of water flow will not appear during the load rejection condition through the Froude number.

Day-ahead generation scheduling of hydropower stations aims to determine the optimal power output and on/off statuses of units during each operation period， which can increase economic benefits of the hydropower station by improving water use efficiency. In this paper， a method for day-ahead generation scheduling of cascade hydropower stations based on the characteristic of daily load curves is proposed. Firstly， typical daily load curves with double-peak or single-peak shape are selected by using a novel judging index. These typical load curves are amplified or narrowed to meet the daily electricity demand， and then they are adjusted to avoid hydropower output’s falling into the prohibited operating zones. The water consumption corresponding to each typical load curve is then calculated by using a two-layer nested optimization algorithm for the short-term economic operation model of the hydropower station. The typical load curve with the minimum water consumption is selected to formulate day-ahead generation plan. A case study using Qingjiang cascade hydropower stations indicates that： ① the proposed judging index can effectively identify those typical daily load curves with double-peak or single-peak shape； and ② compared with actual operations， the generation plan using the best daily load curve with double-peak and single-peak shapes can save water energy consumption by 3.13% and 1.05% respectively.

The environment particularity of hydropower stations in Tibet makes the design process far more complicated than that in the inland. Besides， as an important auxiliary equipment system in the plant， the drainage system affects the safe and stable operation of the power station. This paper introduces the design of the drainage system of the ground powerhouse of Tibet DG Hydropower Station， and briefly describes the characteristics of equipment layout. The drainage system of the power station separates the oil-free drainage system and the oily sewage drainage system to satisfy the needs of environmental protection.At the same time， the installation of freeze-proofing drain pipes and an online monitoring system for the pipe network ensure the safety of equipment and pipelines. The design of the drainage system fully incorporates the characteristics of the local climate environment， which can provide a reference for the selection and design of the same type of power stations.

Velocity is an important issue that has been studied for a long time in stepped spillways. It aims to directly analyze the characteristics of velocity changes， but its laws are complicated and inconvenient to apply. This paper focuses on the study of relative flow velocity changes， and carries out a dimensional analysis of the relative flow velocity of the stepped spillway， introduces the relative step flow velocity， the relative critical water depth， and the number of unfavorable cross-section positions， and analyzes the relative step flow velocity and relative criticality through five model tests with different slopes. The relationship between the water depth， the position of the section without factors， and the slope. The results show that the stepped spillway has a good linear relationship with the stepped spillway’s relative step flow velocity and the uncaused number of cross-section locations. Regardless of how the relative critical water depth and slope change， the correlation is always high. The number of times is in a power function decreasing relationship. According to these laws， the empirical formula of the slope on the relative critical water depth and slope is fitted. The good regularity of relative flow velocity is of great significance to the understanding of the changes of water flow caused by the presence of steps， and provides a new method for the calculation of complex hydraulic characteristics of stepped spillways. The calculation is carried out with the water surface line as an example.

At present， the cases of postponement or failure of approval of some water conservancy and hydropower projects in China are on the rise. This is mainly caused by environmental protection， policy and investment adjustment. Consequently， the long effective period of the suspension order brings inconvenience to the production and life of residents in the project construction area， thereby significantly restricting the overall development of the regional economy and society. This can lead to some social contradictions and stability risks. In this paper， an indicating system that evaluates the impact of the suspension order on the regional economic and social development is proposed. Based on this， the living quality of local residents， as well as the economic and social development in the affected region is evaluated， and suggestions dealing with the impact of the suspension order are put forward. As a case study， our work serves as a reference for subsequent problems of similar projects.

Considering the water turbine structure is complex， modeling method diversity， this paper analyzes the ideal turbine model， the piecewise linear model， neural network model and the interpolation method of different modeling methods of hydro-turbine model， through the study of the modeling of a certain power plant， the analysis of the actual simulation time， turbine’s flow changes， momentum changes， water head variation， research shows that： when using piecewise linear model and ideal turbine model the simulation time is shorter， the modeling process is simple， small fluctuations can more accurately under the condition of dynamic process simulation. When the interpolation turbine model is used， the static process of each working condition can be accurately simulated， but the simulation error increases at the moment of dynamic fluctuation.The error of simulation dynamic process is the smallest when neural network model is used， but the actual simulation time is longer and the modeling process is more complicated.

In order to further standardize the standardized operation technology and procedures for the overhaul of pumped storage units， this paper proposes a virtual reality-based overhaul of pumped storage units′ standardized operation simulation method. Firstly， the multi-source maintenance information is integrated， the maintenance procedures are encoded according to the multi-level coding rules. Secondly， reconstruct the three-dimensional digital model based on the spatial topological relationship. Finally， the maintenance process is simulated， and a standardized operation system for pumped storage units′ maintenance is formed. This method is applied to the actual maintenance process of a pumped storage power station. Practice has proved that the method proposed in this paper can improve the operation efficiency and quality and have good engineering application value.

In this paper， the Euler-Euler model is used to calculate the steady-state solid-liquid two-phase flow of the bulb tubular unit. The external characteristics and flow characteristics under different phases and sediment physical parameters under better working conditions are compared， and the runner blades are analyzed. The conclusions are as follows： After the particle phase is added， the disturbance of the particles causes obvious impacts on the inlet position of the runner. The vortex generated at the bottom of the inlet flow channel and the position of the draft tube dissipates part of the water energy， increases the hydraulic loss and the efficiency of the unit and reduces output. The mud and sand wear parts of the bulb tubular turbine unit should be focused on the bottom surface of the inlet flow passage and the transition part from the inlet flow passage to the guide vane. The increase in the density and concentration of sand particles will reduce the pressure difference between the front and back of the blade， while the change in the diameter of the sand will have a smaller effect on the pressure difference between the front and back of the blade.