Aeration is one of the ecological restoration techniques to solve the water bodies affected by hypoxia. However， dissolved oxygen variations in water will change energy flow and mass balance of solid-liquid interfaces， which lead to resuspension release of heavy metals adsorbed bottom sediments. Taking an organic polluted water body in Zhenzhou District of Yangzhou City as research topic， the aeration depth as the control variable， this paper studies the release law of heavy metals from bottom sediments under different aeration modes. The results of field experiments show that different heavy metals in the sediments have different responses to aeration. Cd increases with the co-precipitation of Fe and Mn. The release of Cu and Fe is sensitive to the change of pH， while the release of Zn and Pb is coordination effect of H⁺ and co-precipitation of Fe and Mn. From the sediment remediation effect， shallow aeration is conducive to the release of heavy metals of sediments， reduce the heavy metal pollution in sediments. The remediation effect of shallow aeration is better than that of deep aeration. During aeration， nitrogen-containing colloid in water flocculates and settles in sediments. However， the amount of phosphorus absorbed by the oxides in the sediment surface is far less than the amount of anaerobic phosphorus released.

In order to solve the problems of narrow valley， large bending angle， collapse， complicated river topography and geological conditions in the downstream of the flood discharge energy dissipation area of the newly built spillway of Shahe Reservoir in Wulong County， Chongqing，this paper takes the two characteristic parameters of radius r and jet angle θ ₁， makes three shape schemes， and uses FLUENT software to conduct numerical simulation. The hydraulic characteristic parameters（flow velocity， pressure and deflecting flow pattern， etc.）are analyzed under the different type of flip bucket energy dissipation.The results show that the scheme with the angle 19.42° and the radius 33.84 m successfully narrates the water tongue drop point， keeps away from the downstream collapse body and reduces downstream scouring.On this basis， different schemes for protection of downstream collapse are compared and the final protection measures are recommended.

By comparing the river ecological assessment standards in different regions， on the basis of the existing commonly used ecological river and lake assessment standards， combined with the characteristics of rivers and ecological environment in the plain river network area of Northern Jiangsu Province， an evaluation index system of plain river ecological status is established， including aquatic organisms， water ecological environment， water space， water safety and public satisfaction. The two indexes of “quality of water” and “public satisfaction” are set as veto items. In view of the analytic hierarchy process-fuzzy comprehensive evaluation model method of the evaluation index system， this paper uses the analytic hierarchy process to determine the index weight， and calculates the membership degree of the index by the classification standard， and then obtains the river ecological status assessment results through the corresponding fuzzy evaluation calculation. Taking Zongliutang River in the plain river network area of Northern Jiangsu （Suqian） as the research object， the results show that it is “medium level”. The conclusion reflects the reality characteristics of the river objectively， which is in line with the actual ecological status of the river in the evaluation year. The case study shows that the proposed evaluation criteria， index system and model calculation method can comprehensively consider the impact of regional river characteristics and the operability of the evaluation model， which provides some reference for similar researches.

In order to explore the interaction relationship between vegetation and water flow， a two-dimensional shallow water mathematical model was established based on the Godunov finite volume method in the old channel of Fuhe River in Ganfu Plain irrigated area of Jiangxi Province. The flow process was simulated numerically by setting the high flow and level flow conditions， as well as the flood diversion flow of 200 m³/s and 400 m³/s under the high flow conditions. The results show that the resistance of vegetation to river flow increases with the increase of upstream inflow， and the extent and extent of its influence on water level also increases， but the effect of water level uplift decreases gradually from upstream to downstream. At the same time， the flow velocity of each section of the river generally increases with the increase of upstream inflow， and the difference of the flow velocity of the vegetated area corresponding to the non-vegetated area also expands further. The flow velocity of the main channel decreases while that of the side bank increases under the condition of no flood diversion. However， it shows the opposite change rule under the condition of flood diversion.Vegetation has an adjustment effect on the flow velocity of the river section， and the channel-bank distributary ratio changes significantly with the change of flow. The above research conclusions can provide important theoretical basis for the analysis of river flood discharge capacity and riverbed evolution， habitat assessment of aquatic organisms and protection of river ecosystem.

The vertical development of micro joints， micro fissures and other macropores in Loess make it highly heterogeneous. In order to study the influence of the spatial heterogeneity on the dispersion capacity of loess medium， combined with the characteristics and advantages of indoor and field dispersion tests， two scale tests on the dispersion characteristics of loess medium were carried out at a test site in the hilly area of western Henan Province. The results show that： ① The value of the dispersivity obtained by the radial convergent flow instantaneous injection method is stable， and the longitudinal dispersion coefficient representing the horizontal direction of the site has a good linear relationship with the average pore velocity；　② The indoor soil column leaching test shows that the dispersion parameters of heterogeneous soil column is significantly larger than that of homogeneous soil column， and the difference reaches an order of magnitude. It is considered that the vertical development of micro joints， micro cracks and other macropores in Loess medium is an important reason for the larger vertical dispersion capacity of loess medium， and its influence on the vertical hydrodynamic dispersion coefficient of loess medium exceeds the degree of non-uniformity of pores and soil column height；　③ The combination of indoor and field dispersion tests has certain advantages in obtaining horizontal and vertical dispersion parameters of loess media.The comparison of test results show that the significant difference of spatial heterogeneity between horizontal and vertical direction of loess affects its hydrodynamic dispersion capacity， that is， the vertical dispersion capacity of loess is significantly greater than that of horizontal direction.

The research uses sodium hydroxide to modify the printing and dyeing biochemical sludge to prepare iron-containing biochar （ISBC）， and the Mn/Cu bimetal is loaded on the biochar by impregnation and calcination method to obtain the Mn/Cu modified sludge biochar catalyst （MSDBC） is used to catalytically activate peroxymonosulfate（PMS） to degrade the hard-to-degrade polyvinyl alcohol （PVA） in printing and dyeing wastewater， and has realized the resource utilization of surplus sludge in printing and dyeing wastewater treatment and the efficient degradation of PVA. Scanning electron microscopy （SEM）， X-ray diffractometer （XRD）， Fourier infrared spectrometer （FTIR） and nitrogen adsorption and desorption isotherm （BET） are used to characterize the morphology and structure of the prepared materials， and explore the best results. The best conditions are that the metal impregnation amount is 5 mmol/g， the Mn/Cu ratio is 2∶1， the pH is 7， the peroxymonosulfate dosage is 6 mmol/L， and the catalyst dosage is 5 g/L，and under this condition， the degradation efficiency reaches 96.5%. EPR and quenching experiments show that the active species produced by MSDBC catalyzed by PMS are mainly SO₄ ^-?， ?OH， O₂ ^-? and ¹O₂， and the main role is ¹O₂ and ?OH.The conversion between metals of different valence states ensure the cyclic regeneration of active sites. Repeated utilization experiments prove the reusability of MSDBC. After 5 uses， there is still a good catalytic effect. In summary， MSDBC is a sludge-based heterogeneous catalyst that effectively catalyzes the degradation of PVA in water by PMS， and has practical application prospects.

Nitrate leaching is the most important form of nitrogen loss in arid land. Because nitrate leaching does great harm to groundwater pollution and causes difficulties in the treatment of groundwater pollution， it is necessary to pay attention to the prevention and control measures of nitrate nitrogen leaching. This paper introduces the current situation of farmland nitrogen pollution and the mechanism process and characteristics of nitrate nitrogen leaching. Five aspects summarize the main prevention and control measures of nitrate nitrogen leaching， including optimization of irrigation and fertilization system， optimization of nitrogen fertilizer types， improvement of soil characteristics， combined application of nitrification inhibitors， and farming and agronomic measures. This paper prospects the best applicable conditions of measures， multi-measure combination schemes， and large-scale popularization and application， and proposes that a comprehensive and systematic study of dry land nitrate nitrogen leaching prevention and control measures should be carried out to further determine the best prevention and control plans. At the same time， it is necessary to further determine the best use conditions of each prevention and control plan， and provide the possibility of combination and cooperation of each prevention and control measure so as to provide a theoretical basis for the better promotion and application of dry land nitrate nitrogen leaching prevention and control technology.

Hyporheic exchange plays an important role in surface water and groundwater quality and the ecological environment of river corridors. The Xilin River is chosen as a typical grassland river to address scarce research on the hyporheic exchange in semi-arid grassland rivers. Both the hydrodynamic and temperature tracer method are used to quantify the process of vertical hyporheic exchange in the upper section of the Xilin River. The applicability of the two methods is also discussed. The results indicate that surface water mainly discharged to groundwater during the experiment period. Vertical hyporheic exchange occurs mainly 20~100 cm below the riverbed surface. Under the influence of the fluidity and inhomogeneity of the sandy riverbed， the process of hyporheic exchange and its response to rainfall vary at different locations of the river channel. Both hydrodynamic and temperature-tracer methods obtain consistent vertical rates of hyporheic exchange， i.e.， -0.2~0.4 and -0.1~0.4 m/d. Compared with the hydrodynamic method， which can be easily influenced by the morphology and hydrodynamic characteristics of the riverbed， the temperature tracer method is accurate and convenient， and more suitable for the study of hyporheic exchange in semi-arid grassland rivers.

Hongze Lake is the fourth largest freshwater lake in China， and also an important water passage in the east route of “South-to-North Water Diversion Project”. Its water environment quality is very important for the water supply guarantee of its surrounding and north water-receiving areas. In this paper， a wavelet analysis based long short-term memory neural network water quality prediction model （WA-LSTM） is established. Firstly， the water quality data of Huaihe entering Hongze Lake is preprocessed， and then it is decomposed into high-frequency and low-frequency signals and input into LSTM model for single factor water quality prediction. Then， the water quality change of Hongze Lake is comprehensively predicted and evaluated by single factor water quality prediction result driven fuzzy neural network based on T-S. The results show that wavelet analysis can capture the characteristics of water quality data better， and the combination of wavelet analysis and LSTM water quality prediction model can greatly improve the accuracy of water quality prediction and that the comprehensive application of WA-LSTM model and fuzzy neural network can effectively solve the problem that single factor prediction can not reflect the overall situation of water quality. The research methods and conclusions of this paper can provide technical support and practical reference for water quality monitoring and management and water resources regulation in Hongze Lake.

As the impact of human activities on water resources and the ecological environment continues to intensify， the interactions among water resources， economic and social and ecological systems are becoming increasingly prominent， the understanding of which calls for a holistic and dynamic coevolutionary perspective. This paper is an attempt to conceptualize the water-society-environment coupling model， and construct the system dynamics model from the perspective of socio-hydrology. The coevolution of the water-society-environment coupling system in the upstream of Hanjiang River from 2006 to 2050 is simulated， and the driving mechanism of its internal components is analyzed by the figure of “Causes Tree” and “Uses Tree”.

In view of the shortcomings in the traditional Nemerow index evaluation method， the analytic hierarchy process and the entropy weight method are used to combine subjective and objective weighting methods to improve the ignorance of the impact of the weight of each pollution index on water quality， and the method of calculating the revised maximum pollution index weakens the leading role of the largest pollution index. Finally， taking Bai River in Nanyang City as an example， the improved Nemerow Index method is used to evaluate the water quality pollution indicators of the four monitoring sections of Bai River from 2015 to 2018， the inverse distance weight method is used to analyze the spatial changes of water quality grades. The results show that the water quality of Dingfengdian Village， Wolong District， Nanyang City is Grade IV every year， and the water quality of the remaining sections are all Grade III or above. There are no Class I and Class V water quality areas in the spatial distribution of grades； in the temporal distribution of water quality grades， the area of Grade III water tends to increase， and the area where Grade IV water appears gradually decreases， and the overall water quality tends to get better. The results serve as a reference for the evaluation of water pollution and pollution discharge supervision in the basin.

The lower reaches of the Yangtze River is broad， and dominated by branching channels. Normally， there is a single section connection between two branching channels， playing a key role in fluvial processes. Taking the single curve Longtan Waterway as an example， this paper analyzes the changes of shoals， typical cross sections and the stability of the river and the influence of water and sediment condition on fluvial characteristics after impoundment of the Three Gorges Reservoir （TGR） is discussed. Results show that， before and after the impoundment of TGR， the bank line is basically stable under the action of river regulation engineering， and the cross-sections maintain narrow and deep. Compared with the wide branch section， the total amount of scour and deposition of Longtan Waterway after the Three Gorges impoundment is getting relatively small. The river bed changes mainly occur below the -20m elevation and around the shoal areas. Generally speaking， after the Three Gorges impoundment， the evolution of Longtan Waterway is mainly affected by the sharp decrease in sediment quantity. The adjustment of the river bed is slow， and the effect of the flood year is relatively large. However， the local scour caused by the big water year is difficult to recover in general years. In the future， it is still necessary to pay attention to the scour changes of the low beach of Xinglongzhou.

Spatial equilibrium allocation for multiple water resources in basin is an important practical issue， and it is also a difficulty in realizing scientific water diversion. A variety of water sources such as surface water， groundwater， and water diversion， unconventional water resources and various water users like domestic water， industry water， agriculture water， ecology water are involved in water resources allocation of the Huangshui River Valley. A spatial equilibrium allocation model for multiple water resources in the Huangshui River Valley including three sub-models for the optimization of total water diversion， each project water diversion and multiple water resources allocation， respectively， based on the hierarchical optimization theory is proposed. The corresponding method and strategy are employed to solve the proposed models. The optimized water diversion scales and water resources allocation plans considering with economic feasibility are obtained under the constraint of strengthening watersaving. The proposed technology and method represents the principles of the water-saving priority， ecological priority and spatial equilibrium in China， which can be used for basin water resources allocation and water diversion project demonstration.

By using system dynamics， the SD model of water resources carrying capacity in Gansu Province is established， the main decision variables in the model are adjusted， five scenarios are designed， and the water resources carrying capacity and structural water demand are simulated and predicted. The results show that the comprehensive type 2 is the best， and it is relatively close to the general goal of the “Gansu Water Security Guarantee Plan”. According to this scenario， the variable parameters that affect economic and social development are set， and the economic scale of water resources can reach 2 575.76 billion yuan by 2035. The total water supply and total water demand are 132.35 billion m3 and 141.29 billion m3， the water supply and demand ratio is 0.936 8， and the structural water demand is based on the proportion of total water demand， from the largest to the smallest is farmland irrigation （70.462 6 billion m3） ， forestry， animal husbandry and fishery livestock （25.169 3 billion m3）， industry （15.970 8 billion m3）， urban public （13.687 7 billion m3）， resident life （10.622 5 billion m3）， and ecological environment （5.374 0 billion m3）.

Soil moisture is a crucial parameter for studying the changes of land-atmosphere system， particularly in the alpine region. Based on the MODIS surface temperature （LST） and Land Surface Temperature（EVI） data sets， this paper first constructs the LST-EVI feature space in Lhasa. Then， it verifies the applicability of TVDI indictor effectively to retrieve the surface moisture in this area. Our results show that TVDI and the measured surface soil volumetric water content have a good fitting effect， and there is a significant negative correlation （r ²=0.71， p<0.05）. Cultivated land LST decreases significantly with the increase in EVI （p<0.05）. Forestland， grassland and wetland are affected by altitude， and LST and EVI are significantly positively correlated （p<0.05）. In the LST-EVI feature space during the 6th period from July to September， the scatter plots are triangular in shape， and both dry edges and wet edges can be fitted well. From a spatial point of view， most regions are in extremely humid （0~0.2） and humid （0.2~0.4） states， accounting for 57.01% and 22.27% of the study area， respectively. Arid regions （0.6~1.0） are mainly distributed in the north. In the southwest and central south， the soil generally appears to be moist and gradually dry. Under the four land use types， soil moisture increased significantly with the elevation （p <0.05）. TVDI basically changes in the same direction with temperature and reverses with precipitation， and the impact of precipitation on soil moisture is more obvious.

In order to investigate the historical spatial and temporal evolution pattern and future state characteristics of water stress in Guangxi， the Mann-Kendall test is used to analyze the trend of water stress in Guangxi from 2002 to 2019 by using the water stress index as an indicator， and the Markov chain risk warning model is applied to forecast the water stress state in the study area from 2020 to 2022. The results show that the overall water stress in Guangxi is high in 2007 and 2009 to 2011， and the distribution of water stress matches the historical drought characteristics. The water stress in Guilin and Fangchenggang shows a significant decreasing trend， with a decrease rate of -0.004 5 /a and -0.001 3 /a. The prediction accuracy of the Markov chain risk warning model during the validation year （2017 to 2019） is 66.67%， 80% and 60% respectively， and the water stress state in Nanning， Beihai， Guigang， Yulin and Laibin will reach a medium-high stress state in 2022.

To explore the soil water holding capacity of Sabina przewalskii forest land is of great significance to the study of soil water movement， solute transport and physiological water use of forest and grass vegetation in Alpine mountainous areas. In this study， the soil of 0~60 cm in the Sabina przewalskii field is taken as the research object. The centrifugal method is used to obtain the soil moisture content of different soil depths under the specified rotation speed. Four empirical models， Gardner， van Genuchten， Broods Corey and Fredlund Xing， are used to fit the measured water content and soil matrix potential， and the fitted soil water characteristic curve is obtained. The results show that： ① van Genuchten and Fredlund Xing models have the highest fitting accuracy and the difference is small. Therefore， both of them can be used as the optimal fitting models for Sabina przewalskii forestland， but the physical significance of the parameters of Fredlund Xing model is clearer. ② The soil water holding capacity of Sabina przewalskii forestland is different in different soil depths， and the difference is more significant with the decrease in soil moisture content. Among them， 40~50 cm soil layer can still release more water under high suction （> 0.1 MPa）， maintain high water content， and have relatively strong water holding capacity. However， 0~10 cm soil layer releases less water， has low water content and relatively weak water holding capacity. In addition， the soil water holding capacity of 30~60 cm soil layer is better than that of 0~30 cm soil layer， so 30~60 cm soil layer is the main water conservation layer of Sabina przewalskii forestland.

The implementation progress of water tax reform of Ningxia Hui Autonomous Region was investigated and evaluated systematically. The reform has achieved remarkable results in the past three years. The water source structure has been optimized. Groundwater overexploitation has been controlled. The enterprises had more power to carry out water-saving transformation. Water resources management has been more standardized， with promoted information management and water use efficiency. Whereas， there are also further needs for optimization of tax exemption policy， unified taxation of public water supply， imperfect classification of special industries， difficulty in levying agricultural water resources tax， and the lag of monitoring and information construction， etc. Based on these analysis， suggestions were put forward for the tax classification， tax standard， Tax preference， tax collection management， departmental collaboration， information construction， and agricultural water tax.

Groundwater reserves and buried depth are the key parameters of water cycle， and their evolution is of great significance to the relationship between water balance and accumulation in the basin. Abstract： Based on the data of water storage and groundwater burial depth retrieved from GRACE gravity satellite， spatial interpolation analysis， regression analysis and Mann-Kendall trend test were used to study the variation characteristics of groundwater storage and groundwater burial depth in the Huang-Huai-Hai Plain from 2003 to 2016. The results show that the groundwater reserves in the Huang-Huai-Hai Plains decrease significantly in recent 14 years with a rate of 1.2 cm/a， of which the rate of decline in Haihe Plains is 1.6 cm/a and that in Huaihe Plains is 0.9 cm/a. Groundwater depth increases by 0.09 m per year on average， showing a significant trend of increase， among which the average annual increase in Haihe Plains is 0.16 m， and the average annual increase in Huaihe Plain is 0.05 m. Based on the analysis of the change of regional water balance and the influence of human water extraction on groundwater， it can be concluded that the overextraction of groundwater is the main reason for the decrease in water storage in the Huang-Huai-Hai Plains. The research results have certain supporting effect on the understanding of the evolution law of regional water cycle and the management and development of water resources under the changing environment.

Parameter calibration is an important research content of hydrological model. The application of simple and efficient parameter calibration method can enhance the efficiency and promote the popularization of the model. In order to explore the application effects of the System Response Parameter Calibration Method in large-scale distributed hydrological models， SRPCM is applied to calibrate the parameters of VIC ideal model and actual model in Dapoling Catchment， based on the sensitivity analysis of parameters. The results in this study indicate that it is feasible and efficient to apply SRPCM to the VIC model； the VIC model is able to simulate the daily runoff in Dapoling Catchment effectively； the average Nash coefficients exceed 0.6 and the relative errors of runoff volume are below 8% during the calibration and validation periods. Therefore， SRPCM proves to be an effective and useful parameter calibration method.

In order to resolve crisis of water quality scarcity and improve water ecological environment， a multi-objective water resources quantity and quality integrated allocation model is established， based on the system decomposition and coordination theory and the principle of “allocation in supply， quality by demand， supply by quality”. At user layer， demand schemes under different water frequencies are obtained by multi-objective function and simulated annealing algorithm. At source layer， demand schemes are obtained by linear objective programming and high-quality water and general-quality water are allocated according to water requirements of demand schemes. According to the target benefit， three kinds of water supply schemes are obtained under different conditions. In a particularly dry year，the ecological benefit of the ecological scheme exceeds that of the economic scheme by about 1，the economic benefit of economic scheme is 0.63 higher than that of ecological scheme，and the total benefit value of balanced scheme is 0.23 and 0.78 higher than that of other schemes. This paper explores the water supply planning and comprehensive benefit evaluation in the optimal allocation system of water resources， and provides a reference for the green development of regional water resources under the background of ecological civilization..

There are more than 30 000 dangerous earth-rock dams in China. Due to long-term service， the mechanical properties of the material of the dangerous earth-rock dam are seriously attenuated and impermeability cannot meet the requirements. There is a greater risk of dam failure. The stability of a dangerous earth-rock dam is an uncertainty problem related to the shear strength of the dam material and the reservoir water level. The traditional reliability analysis method of earth-rock dams does not fully consider the many uncertain factors of the dangerous earth-rock dam， causing the probability of failure to be unable to match theoretical expectations. This paper combines the upper bound theorem， finite element discretization technology， mathematical programming theory with Monte Carlo method， and at the same time uses the shear parameters of the dangerous earth-rock dam material and the upstream reservoir water level as random variables to establish the reliability of the dangerous earth-rock dam. The upper limit method stochastic programming model is analyzed， and the corresponding calculation program is compiled. Finally， a dangerous earth-rock dam in Yunnan is calculated and analyzed， and the failure probability of the earth-rock dam under the design conditions and long-term service conditions is obtained. The research results provide a theoretical basis for the treatment of the dangerous earth-rock dam.

In order to solve the power supply problem of agricultural Internet of Things monitoring equipment in the field environment， a set of agricultural Internet of Things power supply system based on pipe flow generation is designed. The system completes the design of turbine and generator under the working conditions of pipe flow rate of 1.5 m/s and internal water pressure of 200 kPa. On this basis， the system circuit， I/O extended module and control strategy are designed to realize the stable power supply to the monitoring equipment. Through the test measurement， the battery power consumption in 24 h is 43% under the condition of no charge. Irrigation for 8h per day， the lowest power is 69%， and the highest power is 100% within 24 h. The system has a low cost， generates as expected， and can continuously and steadily supply power to agricultural Iot equipment.

During the tunnel excavation， forecast technique for advance geology is an effective means to avoid geological disasters induced by unfavorable geologic bodies. Relying on Dingzhai flood control and drainage tunnel project， the method of combining the seismic elastic wave method and the seismic reflection method was used to detect the unfavorable geologic bodies and the water-rich condition of the rock body aiming at complex geological conditions such as weak interlayers or karst development and rich water in the rock mass in the tunnel construction area. In the receiving hole， the waveform corresponding to each excitation hole was collected. For the areas where the shear wave negative reflection interface exists， the areas where positive and negative reflections alternately appear， and the areas where dense tomographic response appears in the migration image， it is predicted that the joints and fissures here are very developed or there are weak interlayers. According to the seismic signal inversion result， the water-rich areas of the rock mass are predicted， and corresponding engineering measures are proposed. It ensures the safe and efficient excavation of the Dingzhai flood control and drainage tunnel， and also provides a reference for the construction of similar projects.

The periodic fluctuations of the reservoir water level and the complex geological conditions of the reservoir bank slope in hydraulic engineering have caused frequent occurrence of geological disasters of reservoir bank landslides. In order to study the influence of the rate of rise and fall of the reservoir water level and the mechanical parameters of rock and soil on the stability of the bank slope， this paper takes Shanmei Reservoir as the research object. Based on the analytical solution calculation of the unsteady seepage infiltration line of Boussinesq， the three-dimensional slope stability calculation model Scoops 3D is used to calculate the bank slope stability. According to the calculation and comparison of multiple working conditions， the slope stability of the reservoir bank decreases with the increase in the reservoir water level decline rate， and a larger reservoir water level rise rate is beneficial to the stability of the reservoir bank slope. The degree of influence of rock and soil mechanical parameters on the stability of reservoir bank slopes in descending order is internal friction angle， soil weight and cohesion.

In order to give full play to the efficiency of power generation and improve the utilization rate of water resources， the optimal operation of reservoir power generation is used as a hot research by experts and scholars. Luntan Key Water-Control Project， which gives consideration to the comprehensive benefits of flood control and power generation， is taken as an example. Based on building the both mathematical models of the medium-long term power generation and flood pre-release control， then a decision support system with fast online optimization is developed by using SOA architecture and J2EE technology. The results show the system can improve the operation level of the reservoir power generation， and increase electricity generation about 12.3% during the hydrological year from March 2018 to February 2019. And the water abandonment rate of pre-discharge 12 hours in advance is effectively reduced by 21.42% compared with the actual water abandonment rate of dispatching in the actual flood from July 7 to 13， 2019. The system realizes the scientific optimal operation， provides a scientific basis for the management decision， and creates more comprehensive benefits.

Aiming at part of the old Francis turbines are not matched with the latest runner， formulate the transformation and comparison scheme， the hydraulic characteristic model of the flow passage of Francis turbine is established according to the Reynolds averaged N-S equation and standard k-ε equation through local transformation and optimization and set the boundary conditions of the runner. The velocity and pressure distribution of movable guide vane （fixed guide vane） and inner runner in the transformation scheme were obtained based on CFD three-dimensional simulation. The flow field of each scheme under different working conditions was compared and analyzed to predict turbine performance and put forward optimization suggestions. The engineering example indicates that the efficiency of the turbine increases 6%~8% and the output increases 2%~3%. The internal flow characteristics and the operation stability of the turbine are improved， the degree of cavitation erosion of the flow parts is reduced. The research results have a certain reference for the transformation of the similar turbine.

According to the recent work of checking the safety appraisal of small reservoirs， the paper systematically combs out the typical problems in the safety appraisal of small reservoirs. Some suggestions are put forward to improve the quality of safety appraisal of small reservoirs and improve the safety situation of small reservoirs， including clarifying the quality requirements of safety appraisal by classification， strengthening the technical training of safety appraisal， clarifying the key construction contents of small reservoirs reinforcement， strengthening the daily operation management， etc.

High concrete gravity dam has complex geological and operating environment， high load level of dam and foundation， difficult operation and maintenance management， and outstanding safety risk control problems. Deformation monitoring data is one of the ways to directly reflect the structural behavior of the dam. Therefore， it is of great significance for the long-term safe operation of gravity dam projects to make full use of dam safety monitoring information to realize real-time evaluation and dynamic prediction of dam stability. In this paper， combined with the sensitivity analysis of material parameters and the back analysis technology of dynamic displacement， the performance function of anti-sliding stability response surface of the gravity dam is constructed， and a dynamic evaluation model of anti-sliding stability reliability of gravity dam based on dam deformation monitoring data is proposed. The case study of GD gravity dam shows that reliability simulation error of the model is less than 2%， the prediction error is less than 5%， the calculation efficiency and accuracy are high， and adaptability is strong. It realizes the dynamic quantitative evaluation of anti-sliding stability and safety of gravity dam under complex operating conditions and multi-source uncertain factors.

In order to study the aeration with different mathematical models in spillway， the CATIA software is used to establish three-dimensional geometric model of an actual project，and it is introduced into FLOW-3D. The air entrainment model is used to conduct the numerical simulation of the flow field of the spillway. The fluid domain of spillway is obtained by modifying the model through ICEM. Based on the VOF model and the Euler two-fluid model， the FLUENT is used to perform three-dimensional numerical simulation of the aerated water flow in the spillway. The results show that the calculated flow patterns and velocity results of the three models have relatively small differences which are basically consistent with the physical model test results. In terms of pressure calculation results， the calculation results of the entrainment model are in good agreement with the model test results， while the calculation results of the VOF model and the Euler model have large errors. For the distribution of turbulent kinetic energy， the calculation results of the Euler model and the VOF model are basically the same， but they are quite different from the calculation results of the entrainment model. For the aeration rate at the bottom of the center line of the spillway， the calculation results of the entrainment model and the VOF model are unreasonable， and the calculation results of the Euler model are in line with the actual situation. The research results can provide references for the simulation of aerated flow and project planning.

The Kaplan turbine is taken as the research object， and five pores with diameter of 4mm are arranged at the blade inlet to study the effect of blade perforation on the turbine performance. SST k- \omega turbulent model is used to do steady numerical simulation of single-phase flow in the turbine with and without perforation at the blade inlet. Based on the convergence， the transient numerical simulation of gas-liquid two-phase flow is carried out by combining the Mixture and Zwart model. The negative pressure zone， bubble area， cavitation bubble volume and vorticity distribution in runner， efficiency and the pressure at the draft tube inlet are analyzed. The results show that the multiphase flow and cavitation model can well simulate cavitation. The blade perforation can effectively reduce the cavitation and vorticity in runner， and has little effect on the pressure fluctuation at the inlet of draft tube and the efficiency of turbine.

In the operation of a pump-turbine， the process that air supply system injects the compressed air into the runner chamber to pressing the water out， is called the draft tube water depression condition. In this condition， the pneumatic and thermodynamic characteristics that the air decompress from the tank and pass through the pipe are the key problems encountered when a proper air-supply system is designed. The current design methods mainly refer to the theoretical models and empirical principles used in other research fields， like the gas venting process of the long-distance pipe system， which cannot reflect the particularities of the working environment and the structural characteristics of the air-supply system in the pump turbine. At the same time， the numerical simulation research about the air-supply system is still blank both at home and abroad， which puts forward the urgent need of some related researches. In this paper， the full-channel and unsteady numerical simulations are performed to study the draft tube water depression. Some different turbulence models， including Spalart Allmaras Model， Shear Stress Transport κ-ω Model and Scale Adaptive Simulation Model are tested in their applicability in the draft tube water depression researches. And some flow characteristics and thermodynamic changes of the key links in the air supply system are analyzed in the present work.

The hydraulic turbine regulating system plays an important role in ensuring the safe and stable operation of the power grid. This paper sets up a simulation platform for hydraulic turbine regulating system based on the combination of virtual models and real units by connecting the real governor with the servo system based on the nonlinear model of the unit and the unit simulator. The nonlinear modeling and realization methods of the servo system and the hydro-generator set in the hydraulic turbine regulating system are presented. Through the real machine comparison test， the accuracy and superiority of the simulation platform is verified. With the help of the simulation platform， various closed-loop dynamic tests can be carried out， the control law and adjustment parameters of the governor can be checked and optimized， the transition process such as load adjustment of the unit can be reproduced， which is convenient for the analysis and evaluation of the transition process， implement fault inversion and staff training.

Effects of silt mean diameters and silt concentrations on cavitation flow are researched in a two-dimensional nozzle. Silt mean diameters are 0.02， 0.04， 0.06， 0.07 and 0.08 mm and silt concentrations are 0.02， 0.04， 0.06， 0.07 and 0.08. When silt mean diameters are invariant， silt concentrations are changed to consider the effects on cavitation flow and when silt concentrations are the constants， silt mean diameters are varied to consider the effects on cavitation flow. Results show that cavitation occurs at the beginning parts of the jet orifice and distributions of static pressure， vapor volume fraction， and silt particles are axial symmetrical. Cavitation number variations with silt concentrations or with silt mean diameters reflect the effect degree of silt particles towards cavitation flow. With silt mean diameters being 0.06， 0.07 and 0.08 mm， fluctuations of cavitation number with the increase in silt concentrations are much larger than it with silt mean diameters being 0.02 and 0.04 mm. During silt concentrations are fixed， all fluctuations of cavitation number with the increase in silt mean diameters are vaster， demonstrating that silt mean diameters have a more intense effect on cavitation flow. Reasons why silt particles promote the inception and development of cavitation are analyzed. Effects of properties of silt particles， cavitation nuclei， virtual mass force， slip velocity， Saffman lift force and turbulent kinetic energy are considered and studied.

A large area of heavy saline-alkali bare land has been formed in coastal areas due to the sea reclamation， the existence of bare land has done great damage to the regional environment. In order to achieve the plant coverage of the heavy saline-alkali bare land， drip irrigation technology is used to create a micro-environment for plant growth， and its feasibility is verified by pot experiment. The effects of drip irrigation on plant growth and the changes of soil water， soil salt， pH and organic matter under the combined action of drip irrigation and plant growth are studied. The results show that ①compared to atmospheric rainfall， drip irrigation on soil leaching can be ignored， but the 　effect on the growth of Suaeda salsa are obvious， drip irrigation can provide suitable micro-environment for Suaeda salsa sprouted， to ensure that the Suaeda salsa rapid growth in the rainy season. ② The growth of Suaeda salsa increases soil organic and soil permeability， improves leaching efficiency， reduces soil water holding capacity， and contributes to the continuous improvement of saline-alkali land. ③ The pH value of the soil increases after leaching， and the pH value of the soil surface is lower than that of the bottom. The change of the pH value of the soil should be paid attention to when the plants are covered with heavy saline-alkali bare land and leaching of saline-alkali soil. The soil alkalinization should be prevented by applying the soil amendment when the pH value is too high. ④ A large amount of irrigation water supply will increase the plant height and total wet weight of Suaeda salsa in atmospheric environment， can also cause the waste of water resources at the same time. It is recommended to use treatment of experiment S₂（irrigation interval of 7 days in atmospheric environment）， which can not only ensure a better growth status of Suaeda salsa， but also avoid the waste of water resources. The research results can be used to guide plant coverage and soil improvement in heavy coastal saline-alkaline land.

The water supply project of Linping waterworks starts from Yuhang water distribution outlet of Qiandaohu Water Diversion Project， supplying for four waterworks of Linping， Renhe， Hongpan and Tangqi. The diameter of the pipeline is 2.6~1.4 m， the total length is 30.9 km， and the prospective water supply scale is 43×10⁴ m³/d. The project adopts gravity flow water supply mode， with many water users and complex lines， so the calculation and analysis of hydraulic transient process is complex and the design of water hammer protection is difficult. In this paper， the hydraulic transient process simulation software-Hysimcity developed by Huadong Engineering Corporation Limited is used for modeling and calculation， and the pressure change of water supply system in the hydraulic transient process is obtained. According to the hydraulic characteristics of the system， the water hammer protection design of the whole water supply system is carried out. After a lot of trial calculation and analysis， when the regulating valve in front of the waterworks is closed in 120 s， the water hammer problem is effectively solved by setting the pressure relief valve with diameter of 1m in front of each waterworks.

In order to more accurately evaluate the change trend of reference crop evapotranspiration （ET ₀） and crop water requirement in Jiangsu Province under the background of continuous climate change， the modified Hargreaves-Samani model is employed in this study to predict ET ₀ value of the 19 studied stations based on the RCP4.5 and RCP8.5 data in CMIP5， and calculated ET ₀ value is further combined with the single coefficient method to evaluate the change of the total crop water requirement of rice and wheat. The results show that the annual crop water requirement fluctuating upward trend under the condition of both RCP4.5 and RCP8.5 scenarios. The change trend of annual crop water requirement under RCP8.5 lags behind that of RCP 4.5， but the increase range is larger： by 2100， the annual crop water requirement in Jiangsu Province will increase by 74.8%~97.5% and 56.3%~102% under the condition of RCP4.5 and RCP8.5， respectively. By comparing the changes of precipitation with crop water requirement， the difference value in most areas of Jiangsu Province will be more than 500 mm， which needs a larger amount of surface to supplement irrigation water. In conclusion， although precipitation can not meet the crop water requirements under the future condition of RCP4.5 and RCP8.5， this phenomenon can be effectively alleviated through reasonable irrigation methods through a reasonable irrigation method.

The inlet flow pattern of the lateral inlet forebay of the pumping station is poor， and it is easy to produce a large-scale reflux area， which leads to the deterioration of the flow pattern of the inlet forebay of the pumping station. In order to clarify the problem of the flow pattern disorder of the lateral inlet forebay of the pumping station， the Zhaishan Dagou pumping station project in Xuzhou City， Jiangsu Province is taken as the research object. Based on the Reynolds time-averaged N-S equation and the RNG k-ε model， the CFD technology is used to carry out the comparative analysis of the numerical simulation of the lateral inlet forebay of the pumping station under the operation of multiple units with and without rectification measures. The results show that there is a wide range of vortex in the intake pool of the three units without rectification measures. Through the analysis of multi-scheme rectification measures， compared with the original scheme， the flow velocity distribution of the inlet pool is uniform and the flow pattern is the best when the longitudinal bottom slope of the lateral inlet front pool is reduced and the arc guide wall is set up， and the average axial velocity distribution uniformity of the inlet bell tube inlet surface of each unit increases by about 10% compared with the original scheme. The research results of this paper provide a certain reference for the improvement of the flow pattern of the lateral inflow front pool of the pumping station.

Information development of pumping stations is an important link to water conservancy projects， and scientific and effective applications of information evaluation of pumping stations are becoming a key problem to be solved. Based on AHP-fuzzy comprehensive evaluation method， this paper takes a pumping station in Hubei Province as an example， a procedure and method for information evaluation of pumping station is explored， which is practical significant for all-round information development of pumping stations.

In order to explore the law of farmland water and fertilizer loss caused by different planting modes， five typical planting modes in Poyang Lake Plain were selected by using the field runoff pool method to study the agricultural runoff， sediment loss and fertility loss under the condition of natural rainfall. The results showed that the runoff was dry farming mode > water dry rotation mode > water farming mode. The runoff of dry farming mode （mode 1 and mode 3） was significantly higher than that of the other three modes， and the runoff of water dry rotation mode （mode 2） was significantly higher than that of water farming mode （mode 4 and mode 5）； The loss of total nitrogen， total phosphorus and nitrate nitrogen in runoff showed the change law of dry farming mode > water dry rotation mode > water farming mode， and there were significant differences； The amount of ammonium nitrogen loss showed water farming mode > dry farming mode > water dry rotation mode； The sediment loss of different planting modes was mode 1 > mode 2 > mode 3 > mode 4 > mode 5； In the loss of sediment carrying fertility， the loss of alkali hydrolyzable nitrogen， available phosphorus， total nitrogen， total phosphorus and total potassium showed the same law as that of sediment， which showed that dry farming mode > water farming mode； The runoff of dry farming mode was mainly the loss of total nitrogen， total phosphorus and nitrate nitrogen， and the water farming mode was mainly the loss of ammonium nitrogen. The above research conclusions can provide reference for optimizing farmland planting structure， reducing farmland non-point source pollutant emission， and improving farmland fertility and sustainable utilization ability.