In the context of global warming， drought becomes more and more frequent， causing negative impacts on agricultural and social activities. Based on the daily precipitation data of meteorological stations from 1960 to 2019 in Xinjiang Uygur Autonomous Region， this paper calculates the Standard Precipitation Index （SPI） in a timeframe of 1， 3， 6， 9， 12， 24 months， then time series SPI at different temporal scales are predicted by ARIMA model and EEMD-ARIMA combined model. And the effectiveness of model is judged by the evaluation standard of RMSE， MAE， and R² . The main conclusions are as follows： the forecast results of the EEMD-ARIMA combined model in Xinjiang are consistent with Xinjiang yearbook. Therefore， the combined model can be used in the prediction of drought. Compared with ARIMA model， EEMD-ARIMA combined model can effectively reduce the non-stationary of series and match the SPI series better. The prediction accuracy of EEMD-ARIMA combined model is higher than that of ARIMA model at each time scale. The combined model has significant advantages in drought prediction.

Rainfall is the most important factor in the meteorological data, which has great influence on the runoff process. In order to predict the runoff process under different precipitation scenarios in the future， SWAT model and stochastic precipitation simulation coupled with Markov chain-Gamma distribution are combined. Taking the basin above Wangkuai Reservoir as the research area， this paper constructs SWAT model and calibrates and verifies its parameters. Based on daily precipitation data of Fuping Station in 60 years， the daily precipitation process corresponding to the annual precipitation of 800， 550 and 300 mm are generated by constructing stochastic simulation model under different precipitation levels， which are input into SWAT model and output monthly runoff process. The results show that the SWAT model has good simulation results for the runoff in the study area； the annual runoff under three precipitation scenarios is 5.97， 2.79 and 1.51 m³/s， and the maximum monthly runoff is 17.81， 7.01 and 4.08 m³/s respectively.

The river and tidal dynamics in the Pearl River Delta （PRD） are disturbed by strong human activities and changes different from the natural evolution. To explore the evolution of river and tidal dynamic characteristics in the river network of the PRD in recent years， based on the hourly water level and discharge data of two floods in the PRD， “99.7” and “17.7”， this paper adopts the Fourier transform method to obtain the residual water level （low frequency） and tidal （high frequency） components in the water level time series for comparative analysis. The results show that the relation curves of residual water level and discharge at Makou and Sanshui stations move down， with lower residual water level at the same discharge； whereas the residual water levels near the lower mouth of the PRD rise slightly， making the decrease in the residual water level slope； the increase in water depth results in the decrease in the resistance of tidal propagation， which leads to the attenuation rate of tidal range also decreases accordingly. The riverbed down-cutting caused by reservoir construction and waterway regulation is the main reason for the change of river and tidal dynamics of the PRD in recent years.

Taking the Balager River Basin in Inner Mongolia as a typical research object， based on the data of hydrometeorology， vegetation characteristics， topography and landforms and grassland management methods， a precipitation-runoff simulation experiment was designed， and the MK method was used to conduct a sudden change analysis of hydrometeorological sequence， Kriging Spatial interpolation reveals the spatial distribution characteristics of soil-vegetation-root system， precipitation-runoff model simulates the characteristics of grassland watershed runoff generation， establishes a mathematical model of precipitation intensity-topography slope-runoff coefficient of grassland watershed and SWAT model to explore the impact of environmental changes on grassland surface runoff. It shows that： ① The watershed runoff mutation occurred in 1998， the lowest temperature mutation was the earliest （1982）， and the precipitation mutation was the latest （2001）， with an interval of 19 years； ② The soil saturation and permeability coefficient ranged from 0.19 to 14.23m/d， spatially The variability is significant， the average value is only 2.87 m/d， and the maximum and minimum dry bulk density are close to the average. The capillary rise water content range is the largest， followed by saturated water content； ③ The runoff coefficient is 0.424， and the contribution rate of human activities to the change of runoff coefficient is about 20% before the abrupt change， and more than 50% after the abrupt change. ④ SWAT model shows that the contribution rate of climate change and human activities is 79% and 21% respectively.

In order to solve the problem of regional water resources shortage and unreasonable utilization， the optimal allocation of water resources has become one of the research focuses in recent years. Taking a county in Henan Province as the research area， the optimal allocation model of water resources is solved by using the characteristics of fast convergence speed and strong global optimization ability of whale optimization algorithm， and the allocation schemes in 2025 and 2030 are obtained. The results show that in 2025 and 2030， the water resources of the county can fully meet the domestic and ecological water demand. There is only a small amount of water shortage in the production water department， with the water shortage rate within 10%， basically meeting the future water demand， and the allocation schemes is scientific and reasonable.The whale optimization algorithm overcomes the problem of the slow convergence speed of the traditional optimization algorithm， and shows good adaptability and effectiveness in solving the problem of optimal allocation of water resources.

The construction and operation of the Three Gorges Dam and other reservoirs in the Yangtze River have changed downstream runoff process and annual distribution， and also changed the hydrological staging law of the middle and lower reaches of the Yangtze River. In order to analyze the influence of the Three Gorges Reservoir operation on the flood seasons and dry seasons staging of the middle and lower reaches of the Yangtze River， two hydrological staging methods based on the monthly runoff reconstruction sequence of seven hydrological stations in the middle and lower reaches of the Yangtze River are used to calculate the beginning and ending time of the flood and dry seasons of each station. Results show that flood seasons in the middle and lower reaches of the Yangtze River from 1961 to 1980 ranged from May to October； during 1981 to 2002， the flood seasons from Yichang to Chenglingji was from June to October， while it is May to October from Chenglingji to Datong； during 2003 to 2016， the variation analysis method shows that flood seasons in the middle and lower reaches of the Yangtze River after impoundment of Three Gorges Dam is from May to September， but fuzzy statistical method shows that flood seasons during this period is consistent with the natural runoff law from May to October. If the impact of the Three Gorges Reservoir's water storage are removed， results of this two methods are the same as hydrological staging from 1981 to 2002. Further analysis reveals that in the middle and lower reaches of the Yangtze River， runoff during May and October is most greatly affected by Three Gorges Dam’s operation， and the upper reaches are more significantly affected than lower reaches. The operation of the Three Gorges Reservoir is the main reason for the change of the starting and ending time of the flood season in the lower reaches of the reservoir.

Aiming at the problem of water delay time in the optimal scheduling of reservoirs， which leads to unbalanced water volume in the long-term scheduling and lagging of reservoir storage， based on the difference in the impact of water delay time on the optimization of water storage and the optimization of power generation. For analysis， the adjustment calculation method only considers the impact of the water delay time caused by the outflow of the adjacent upper reservoir， and proposes a reservoir group storage optimization scheduling model considering the water delay time. Combined with the stepwise optimization method， the model is solved in blocks， and the reservoir with beneficial conditions in the Anzhao New River Basin are selected as examples to verify the effectiveness of the model. The results show that this model meets the water storage demand of the reservoir， reflects the water storage benefit affected by the water delay time， and exerts the water storage potential of the reservoir group under the premise of ensuring the safety of operation.

The Heilongjiang River Basin is a typical high latitude cold region river in northeast Asia， with winter ice periods often exceeding 200 days.The results of scientific research related to ice cream in the Heilongjiang River Basin are summarized from 3 aspects： theoretical research， phenomenological laws， and applied research.In terms of theoretical research， there are relatively few teaching courses for ice cream study， and scientific research on ice melt in the Heilongjiang Basin is limited to the Heilongjiang Basin and a few research units outside the basin.Ice dam flooding phenomenon pattern， in the river characteristics conditions， by precipitation， river tank storage， the opening period of the river temperature and other hydro-meteorological factors have a greater impact.In ice monitoring and forecasting， it is also necessary to improve ice monitoring equipment and methods with the help of advanced technologies such as telemetry and remote sensing to improve the accuracy of forecasting.In terms of disaster response， joint defense and scheduling， blasting and joint scheduling have become difficult points in Heilongjiang's prevention and mitigation.With the development of modern observation technology， the ice cream monitoring technology will develop in the direction of continuous， automated and unattended，further improving the forecast results.

The completion and operation of the diversion project between Fuxian Lake and Xingyun Lake has changed the hydrological and hydrodynamic conditions of Fuxian Lake， which will have a certain influence on the ecological balance of the lake area. The linear trend analysis method and M-K method are used to diagnose and test the variation trend and its significance of water level in Fuxian Lake from 1953 to 2019， and the jump of the series process is analyzed by cumulative anomaly method. Method based on IHA （Indicators of Hydrological Alteration） and RVA （the Range of Variability Approach） method， to haikou gage of fuxian lake， water level observation data from 1953 to 2019 as the foundation， with the most close to the mutation year （2011） 2009 fuxian lake not from haikou to xingyun lake river discharge flow variation points， 24 indicators， such as monthly water level， annual extreme water level and their occurrence time， frequency and duration of high and low water level， times of fluctuation and fluctuation water rate， are calculated to comprehensively describe the ecological water level demand of Fuxian Lake under the state of natural outflow from 1953 to 2008. The variation degree of water level in Fuxian Lake from 2009 to 2019 is revealed through the calculation of variation degree. To evaluate the satisfaction degree of lake ecological water level from 2009 to 2019. Calculation results from 1953 to 2019， the annual average water level of Fuxian Lake shows a trend of insignificant fluctuation and decline， and the annual demand for suitable ecological water level is 1 721.48~1 722.74 m， among which the suitable ecological water level from January to December is successively as follows： 1 721.8~1 722.46， 1 721.69~1 722.35， 1 721.6~1 722.25， 1 721.54~1 722.16， 1 721.48~1 722.12， 1 721.56~1 722.19， 1 721.9~1 722.35， 1 722.02， 1 722.06~1 722.74， 1 722.01~1 722.71， 1 721.93~1 722.61 m. The highest water level in the year is 1 722.18~1 722.87 m， and the occurrence time is 235~304 days （annual volume day）. The lowest water level is 1 721.40~1 722.03 m， and the occurrence time is 127~154 days （annual volume day）. The high water level is 1 722.27 m （0~2 times）， and the average duration is 23~150 d/time. The low water level is 1 721.98 m （0~2 times）， and the average duration is 38~183 d/time. The inter-diurnal flood frequency is 8-18 times， and the flood rate is 0.014~0.020 m/d. The diurnal falling times is 5~14， and the falling rate is 0.004~0.025 m/d. Compared with the period from 1953 to 2008， the water level of Fuxian Lake changed moderately from 2009 to 2019， and the overall change degree was 52.2%. The overall satisfaction degree of lake ecological water level from 2009 to 2019 was 23.5%. The analysis results can provide scientific reference for water ecological protection and water resource management in Fuxian Lake.

In order to reveal the effect of the social economy， resources and ecology of the watershed on the water environment carrying capacity， Baiyangdian Watershed is selected as the study object， based on the frequency analysis and principal component analysis to construct an evaluation index system for the water environment carrying capacity of the Baiyangdian Watershed， and twelve water environment carrying capacity indexes are selected. Meanwhile， the control chart and watershed development planning method are combined for the first time to determine the threshold interval of index， and the BP neural network model of water environmental carrying capacity suitable for Baiyangdian Watershed is established according to the evaluation the water environmental carrying capacity of Baiyangdian Watershed. The results show that 2012， 2013 and 2015 were in a poor bearing state， while 2014， 2016 and 2017 were in a medium-sized carrying state. The evaluation results are consistent with the actual development trend of Baiyangdian Watershed， and also indicate that factors such as per capita GDP and groundwater exploitation will bring heavy pressure to the water environment of Baiyangdian Watershed in the future. The study shows that the index system classification standard of water environment carrying capacity can be determined more accurately by combining the control chart and the watershed development planning method. Meanwhile， the evaluation of the watershed water environment carrying capacity can be carried out accurately and effectively based on the BP neural network model， which serve as a reference for the coordinated development of the watershed water environment and economy.

Based on the stress analysis of sediment particles on the slope and by introducing the concept of relative exposure， the critical condition of single particle sediment starting on slope is deduced by the rolling mode， combined with the runoff-seepage coupling model， the critical water depth expression of sediment incipient motion on the slope is further derived. The expression shows that the critical water depth is mainly related to the physical properties of sediment itself， slope and relative exposure. When the Δ? is tightly arranged， the slope range of the expression is 0~30°. The validity of the formula is verified by the measured data. The results show that the calculated value of the formula below 10 mm is close to the measured value and the accuracy is high. At the same time， there is a "boundary particle size "， which exceeds the particle diameter value， and the relative error between the calculated value and the measured value will increase significantly.

In order to further clarify the impact of changes in the meandering of urban rivers on the ecological environment of the river， this paper， based on the current situation of the study area， starts with two aspects of biological habitat and river water quality， and selects effective habitat area （WUA）， pool and riffle， chemical demand oxygen content （COD） and total phosphorus （TP） are used as characteristic indicators， and the river section near Laoniu Bay of Nansha River in Beijing is selected as the research object. The basic data is obtained by combining relevant data with field surveys. The different plane meandering degrees of the selected river sections are simulated by using MIKE21 and RIVER2D. According to the simulation results， the effective fish habitat area and the water quality changes of the selected control section are analyzed so as to meander the river plane. The influence of serpentine morphology changes on the river ecological environment is quantitatively studied. The results show that as the meandering of the river becomes smaller， the target fish habitat area and the number of deep pools and shoals gradually decrease. WUA accounts for 28.9% of the total river area to 11.2%， and the number of deep pools and shoals decreases from 10 to 4. River water quality is gradually getting worse， and both COD and TP show an overall upward trend. Finally， it is clear that the ecological environment of the river will deteriorate as the meandering becomes smaller.

The long-term operation of landfill site has the problem of failure of anti-seepage measures. The groundwater pollution caused by leachate leakage will threaten human health seriously. A landfill site in Shandong Province is taken as the research object， and the field survey data and long-term groundwater observation well are used as data sources. Based on the GIS platform， combined with the MODFLOW and MT3DMS program package， a numerical model of the groundwater flow field and solute transport in the study area was established. Ammonia nitrogen and nitrate were selected as simulation factors to predict the migration of leachate pollutants within 15 years before and after grouting. The results showed that the maximum range of ammonia nitrogen and nitrate exceeding the standard before grouting was 1 929.61 and 1 613.14 m respectively. The concentration of pollutants near the landfill site is kept at a high level， which will have a serious impact on the surrounding groundwater environment. The maximum range of ammonia nitrogen and nitrate exceeding the standard after grouting was 705.75 and 498.34 m respectively. After grouting， the risk source was blocked and the pollution channel was cut off. Therefore， the pollution source was controlled and the downstream pollution concentration gradually decreased. This study can provide a theoretical and practical reference for the prevention and control of groundwater pollution by leachate.

Due to the geographical environment problems in Fuzhou City， the water level of the rivers in the urban area is much low and the fluidity is very poor， which generated the water pollution problem. In order to maintain the water level of Fuzhou's river course to reach the landscape level and effectively alleviate the water pollution problem，for the river network of the Jinan River-Guangminggang River Basin in the downtown area of Fuzhou，a one-dimensional unsteady flow Saint-Venant equation set is established through the InfoWorks ICM hydrodynamic model. At the same time， nine scheduling schemes are designed based on the actual dispatching situation in Fuzhou. The objective function is to establish whether the control target can be achieved，the opening time of the pump station，the number of gate openings， and the average length of the key section not reaching the landscape water level as the objective function. Comparing the results of 9 scheduling schemes，adjusting the pump and gate configuration， and giving a recommended scheduling scheme. At the same time，a water quality model is established，and water environment dispatching simulations are carried out. The time for the BOD level to change from type Ⅳ to type Ⅲ is used as the objective function to evaluate the dispatching plan，and finally the optimal dispatching plan is given for the realization of the urban area. The study of the "water more water dynamic" dispatching scheme provides an important basis.

At present， ensuring the ecological flow demand of the multi-water ecological target is one of the main problems faced by the water resources management of the North Canal Basin. The DHI-MIKE11 model system modeling platform is used to construct the hydrological and hydrodynamic model of river network based on the flow demand of ecologically sensitive targets. The long-term series of measured hydrological data from the 2015 and 2011 hydrological yearbooks are used to study the multi-water ecological demand protection effect of the river basin of the different scenarios. The results show that the simulated value of the hydrological station is basically the same as the measured value of the hydrology， and the combination plan of gate dams regulation + river water reduction + agricultural water-saving has a good effect. This model aims to provide the basis for the research on the river channel multi-objective ecological flow guarantee scheme， and to provide technical support for the decision-makers of the water management departments based on the multi-water flow dispatch.

In order to study the spatial and temporal distribution characteristics of nitrogen and phosphorus emissions from agricultural non-point source pollution in Jingui River Pilot Area， 15 monitoring points were set up in the pilot area according to its hydraulic connection. The nitrogen and phosphorus concentration changes were monitored monthly from 2017 to 2018， and the water quality monitoring data of two years were analyzed. The results show that： the concentration of nitrogen and phosphorus in the Jingui River showed a fluctuating upward trend， and the concentrations of total nitrogen， ammonia nitrogen and total phosphorus increased significantly after the tributaries of fish pond drainage and aquaculture wastewater flowed into the river. Under different underlying surfaces， the correlation between ammonia nitrogen and total nitrogen was significant， and the correlation was as follows： Farm > paddy field > fish pond > fruit forest； the concentration of nitrate nitrogen had little difference under different underlying surfaces. The concentration of nitrate nitrogen in groundwater is about 10 times higher than that in other surface water monitoring sites. The results show that the nitrogen and phosphorus concentrations of the monitoring points on the underlying surface of farmland and fruit forest are rainy season > dry season； the concentration of nitrogen and phosphorus on the underlying surface of aquaculture farms and fish ponds was dry season > rainy season. The nitrogen and phosphorus emissions of livestock and aquaculture in the test area have a great impact on the downstream water quality. Strengthening the management of aquaculture wastewater discharge is suggested.

Vegetation exists widely in nature， the existence of the vegetation of the river flow structure and sediment has great influence for exploring vegetation under the action of turbulent kinetic energy distribution characteristics， using multiple rows of symmetrical layout design working condition of density of two groups， using PVC round rod simulate the submerged vegetation group of rigidity， a flume test probe size density group for the turbulent kinetic energy distribution characteristics of vegetation under the condition of test show that the influence of Vegetation density group had no significant effect on the upstream turbulent kinetic energy distribution， and downstream effect is severe turbulence kinetic energy density condition in vegetation vertical distribution of cuhk rear produce greater volatility， turbulence kinetic energy peak larger turbulent kinetic energy distribution along the cuhk is bigger， turbulence kinetic energy density peak position ahead of the turbulent kinetic energy in vegetation in cross-sectional points on both sides of the turbulent kinetic energy increases， and the second row of vegetation on both sides of the turbulent kinetic energy significantly greater than the first row of vegetation group on both sides of the turbulent kinetic energy， the vegetation of the downstream turbulence kinetic energy profile is roughly M type distribution， turbulence kinetic energy peak size and density were positively correlated The experimental results of turbulent kinetic energy can provide more basis for the related research of vegetation group channels.

In order to study the influence of the guide vanes on the performance of the multi-stage turbine mode designed according to the theory of hydraulic prime mover， this paper takes the first stage of a two-stage turbine mode as the research object， designs five new-type space stage guide vanes with different number of guide vanes as its interstage guide vanes The external characteristic curve， internal flow pattern and pressure fluctuation data of each component were analyzed. The results show that： with the increase of the number of inter stage guide vanes， the efficiency of hydraulic turbine first increases and then decreases， and the available water head presents an increasing trend. The internal head loss of the new space guide vane and runner first increases and then decreases， and the efficiency reaches the highest when the number of guide vanes is 12. With the increase of the number of guide vanes， the pulsation amplitude of the first stage runner increases， while the amplitude of the main frequency pressure fluctuation in the second stage runner decreases. The fluctuation amplitude at the inlet and outlet of the new type of space guide vane increases. Properly increasing the number of guide vanes can improve the flow pattern in the runner and reduce the pressure fluctuation amplitude in the turbine.

In order to explore a universal long-distance booster chlorination scheme， a series of comparison experiments of one-time chlorination and booster chlorination under different initial chlorine concentrations is carried out， the residual chlorine decay and production of two typical disinfection by-products chloroform （CHCl₃） and dichloroacetonitrile （DCAN） are compared and analyzed for the drinking water in two water treatment plants with different water qualities. The results show that when the total chlorine demand of water distribution system（WDS） is less than 1 mg/L， the finished water can be disinfected by a single injection of chlorine； when it is higher than 1 mg/L， booster chlorination is recommended， and the booster chlorination stations should be set in the pipeline network when the residual chlorine decays to about 0.2 mg/L. Compared with one-time chlorine injection， the decay time extension rates of residual chlorine from two water works are 9.5%， 13.8%， 15% （WTP1） and 12.5%， 16.7%，22.9% （WTP2）， respectively. In the case of booster chlorination， the total yields of CHCl₃ decreases by about 12%~25% and DCAN by about 8%~18%， respectively. Booster chlorination can significantly reduce the attenuation of residual chlorine， effectively reduce the formation potential of carbonaceous disinfection by-products （C-DBPs） and nitrogenous disinfection by-products （N-DBPs） in WDS. Moreover， when the chlorine demand is higher and the water quality is worse， the advantage of Booster chlorination is more obvious than that of water with good water quality， but the overall change of DBPs is similar. When the dosage ratio of initial to booster chlorine is 1∶1， the residual chlorine in the pipeline network remains the longest， and has the best uniformity. In addition， the control effect on the generation of CHCl3 and DCAN is optimal. The conclusion still holds as the total chlorine demand changes. Choosing 1∶1 is recommended as the optimal ratio between the initial and booster chlorine dosage.

Online monitoring of hydropower equipment can provide effective operation information and instruct operators to take corresponding measures， but the heat generation and heat dissipation process of the generator motor is complex， and the short-term warning information is difficult to meet the real needs of the site. Therefore， a time-based convolution network （Temporal Convolutional Network， TCN） temperature real-time dynamic early warning model is proposed in this paper. First， the maximum information coefficient （Maximal Information Coefficient， MIC） is used to analyze the relevant variable set. Second， the appropriate input dimension is set， and TCN and attention trained with historical monitoring data Attention Mechanism regression prediction model is established. Compared with other deep models through testing， the practical value of the proposed model is verified. Finally， in order to increase the effectiveness of real-time early warning， this paper uses the index kurtosis and skewness of the statistical theory to analyze the residual sequence set and design a real-time early warning strategy that can adapt to the real situation on site. The proposed scheme can better meet the actual needs of the site through the real-time data test of a large power station hydropower unit.

Prestressed gate pier is an important structure of large discharge structure， and the tensioning sequence of prestressed anchor cable directly affects the stress， deformation and structural safety of the pier structure. In this paper， a staggered symmetric tensioning method suitable for the project is put forward in combination with the No.2 overflow dam section of a reservoir in Sichuan Province. The influence of two different tensioning sequences of anchor cables on the stress state and deformation law of the pier under various working conditions is compared and analyzed by using the three-dimensional finite element method. The calculation results show that the stress state and deformation law of the pier are greatly affected by the tensioning sequence of the anchor cable， and the staggered symmetrical tensioning method can obviously improve the stress state of the pier. The research results have an important guiding significance for this project and important reference value for similar projects.

Peridynamics is based on the idea of non-local action and directly solves the motion equation in the integral form， thus avoiding the singularity of traditional local differential equation in solving discontinuous problems. It can effectively solve continuous and discontinuous deformation problems and has been successfully applied in many fields. A bond-based peridynamics model is established to simulate the seismic dynamic response of a concrete gravity dam. It is implemented in FORTRAN90 programming language. In the proposed model， the input of seismic wave is realized by applying seismic acceleration to the three layer virtual node. The paper first verifies the accuracy and effectiveness of the model and the program through two examples of a force acts on the free end of the cantilever beam and the dynamic response under the input periodic motion at the bottom. Finally， the numerical simulation of the seismic dynamic response of the concrete gravity dam is performed based on the proposed model. The results show that it is feasible to simulate the seismic dynamic response of the concrete gravity dam with the bond-based peridynamics model and provides a new idea for the numerical simulation of seismic response of the concrete dam.

In order to explore the stress-strain characteristics of composite geomembrane in the application of reservoir seepage control， the Baishatang Reservoir in karst areas uses composite geomembrane for reservoir basin and bank seepage control as an example， the finite element software MIDAS GTS NX is used to calculate and analyze the stress and strain of the composite geomembrane. The results show that the deformation law of the composite geomembrane is consistent with that of the reservoir profile， and its maximum deformation is slightly smaller than the maximum deformation of the reservoir profile. Under the action of changes in the reservoir water level and groundwater level， the soil on the reservoir bank will deform laterally toward the reservoir basin. Reservoir storage reaches the check level， and when the underground water drops to the bedrock surface， it is the most dangerous working condition. The maximum sinking deformation of the reservoir profile and composite geomembrane are 30.83 and 29.67 cm， and the maximum lateral deformation is 9.92 and 8.58 cm， respectively. The tensile safety factor and tensile strain safety factor are both less than the allowable safety factor 5.0.

The problem of soil salinization in the Yellow River Delta is very serious， which is to be solved urgently with a modernized scientific and efficient approach to control land salinization. This paper puts forward a modernized technical system of soil salinization remediation in the Yellow River Delta， which is composed of water storage irrigation network， underground pipe drainage network， sewage discharge network， intelligent decision and support system based on the Internet of Things， effect monitoring network and so on. This system is applied to the land development project of the Yellow River estuary area. The results show that the parameters of the space and layout depth of underground pipe are reasonable and the technical system of soil salinization with the core of the underground pipe discharge technology is suitable for the Yellow River Delta Area， which is effective for the development and improvement of the coastal heavy saline-alkali land.

Seismic safety review is an important part of sluice safety appraisal. In order to ensure the safe operation of the sluice structure， seismic safety review research is required. Taking a drop sluice as an example， based on ADINA finite element analysis software， a three-dimensional finite element model of the drop gate chamber structure is established， and the seismic response of the chamber structure is calculated and analyzed by using the mode decomposition response spectrum method， and the seismic safety evaluation of the sluice is carried out according to the calculation results. The results show that： ①there is a tensile stress of 2.00 MPa at the intersection of the pier and the bottom plate of the gate. According to the structural mechanics method， the maximum tensile stress at this place is 4.41 MPa， which meets the safety requirements. ②There is a large tensile stress area at the bottom of the middle span of the highway bridge of the drop sluice and part of the bottom plate of the hoist room， which is far beyond the standard value of dynamic axial tensile strength of concrete. For the sake of safety， the corresponding anti-seismic reinforcement measures should be taken. ③The anti-sliding stability safety factor of the sluice chamber structure is greater than the standard value of sluice design code （SL 265-2016）， which meets safety requirements. ④The anti-seismic safety of the drop gate chamber structure meets the requirements of the standard for the seismic design of hydraulic structures （GB 51247-2018）， but there are seismic defects which do not affect the overall safety， and its seismic grade is evaluated as Grade B.

The original excitation device of Jiangdu No.4 pumping station has been used for 10 years， which leads to many failures such as excitation failure and motor out of step due to equipment aging and other reasons. In view of the above problems， WKLF-102 excitation device is selected and relevant technical improvement is carried out.The new excitation system adopts three-phase control full bridge rectifier technology， analyses the excitation transformer， solves the problems of excitation excitation resistance and excitation transformer overheating and thyristors were bad. Through an analysis of synchronous motor asynchronous starting rotor induction current and synchronous motor excitation potential vector optimal moment， polarity accurate angle excitation mode is put forward and optimized. It also optimizes the control logic of motor out of step and double closed-loop control to solve the problems of motor out of step and slow regulation. The effectiveness of the renovation is verified by field test data.

In order to explore the response mechanism of regulated deficit irrigation to the physiological development of walnut trees under drip irrigation conditions， field experiments are conducted to perform light deficit （75% ET_C ） and moderate water deficit （50% ET_C ） during the flowering and fruit setting period and the fruit expansion period. After irrigation， the soil moisture content of 0~40 cm in the soil layer changes the most， and the change of 80~120 cm was the smallest. The greater the water deficit， the smaller the soil moisture content and the corresponding decrease in the change range. Regulated deficit irrigation suppresses the new branch and leaf area index to a certain extent. After rehydration， the new branch growth trend remained unchanged. The leaf area index of the mild water deficit in the flowering and fruit setting period recovered and was higher than normal irrigation. Other treatments did not recover. Walnut trees increased the length and breadth of the fruit and the weight of single fruit in the flowering and fruit setting period of regulating deficit， but all other treatments decreased （P<0.05）. The slight water deficit in the flowering and fruit setting period will reduce the growth of branches without affecting the yield of walnut trees， so that nutrients can be supplied for fruit growth. Growth periods that are not suitable for water deficit or excessive water deficit will reduce yield.

In order to realize intelligent and precise fertilization， a formula fertilization system based on the Internet of Things is designed and studied. The system includes variable frequency control equipment， first control equipment， remote constant flow valve to control flow， centrifugal pump， raw liquid tank， fertilizer tank， etc. The system adopts the Internet of Things control method to control the ratio of the fertilizer flow rate of the feed channel of the raw liquid tank to the fertilizer flow rate of the fertilizer channel of the fertilizer tank and the constant liquid level in the fertilizer tank， so that the formulated fertilizer can be diluted according to the set dilution factor. The system can save each fertilization record， including the crop area， quantity， fertilization amount， dilution ratio， etc.， and can also be connected with a remote control platform to realize remote control functions， so that field fertilization becomes intelligent， efficient， controllable and economical.

In order to analyze the influence of the division pier on the internal flow pattern and pressure fluctuation of a two-way passage， CFD technology is used to study the flow pattern and pressure fluctuation characteristics in the two-way reversible pumping system without or with division piers. The accuracy of numerical simulation is verified by the model test. The results show that the arrangement of the division pier can slightly improve the uniformity of the flow velocity at the impeller inlet， and improve the low flow rate on both sides of the inlet passage. The main and secondary frequencies of impeller and guide vane remain unchanged， and the amplitude changes little. Due to the influence of the residual circulation at the outlet of the guide vane， the time-domain distribution of the side wall of the outlet passage is different. At the blind end and side wall of the inlet passage， the fluctuation amplitude is reduced. The research results can provide a reference for the study of pressure fluctuation of two-way reversible pumping system.

Reducing salt stress and improving the efficiency of land agricultural production are an important foundation for the development and utilization of coastal saline-alkali land resources. The application of biochar as a soil amendment can effectively improve soil fertility and reduce abiotic stress， thereby increasing crop yield and quality. A pot experiment is conducted to study the 0%~8% addition amount of biochar ［0% （CK）， 0.5% （B2）， 2% （B3）， 4% （B4） and 8% （B5） （W/W）. Dry weight ratio） of the proportion of addition］ on the growth and water consumption of tomato in coastal saline-alkali soil. The results show that increasing the proportion of soil biochar application has significantly （p<0.05） improved water use efficiency， improved soil physical and chemical properties， and reduced plant leaf sodium ion concentration， accelerated tomato growth and increased its yield. With the increase in the biochar application rate， the plant height， leaf area and biomass value of B3， B4 and B5 treatments are significantly higher than those of CK and B2 treatments. Compared with the control， under the improvement of biochar， the consumption of tomato plants. The water volume is significantly reduced， and the crop has a higher utilization rate of soil water. The water use efficiency has increased by treatments B2， B3， B4 and B5， which has increased by 7.7%， 22%， 31% and 33.24% respectively. The research results can provide a theoretical basis for using biochar to improve coastal saline soil.

In coastal reclamation area of Jiangsu Province， fresh water resources are scarce and rainfall resources are abundant. The construction of artificial drainage system can promote the leaching effect of natural rainfall on farmland soil salt and achieve different desalting goals. Based on the daily meteorological data of Dongtai in Jiangsu Province for 62 years， a dynamic model of salinity is established based on the simulation result of DRAINMOD. The variation process of salinity in soil under different drain conditions is analyzed， and the relationship between desalination effect and drainage intensity in the study area is established. The results show that the DRAINMOD model predicts the dynamic change of groundwater level well， and the predicted value of soil salinity by the salt model is basically consistent with the measured value. The relationship between soil desalination period （N/a）， depth （D/m） and spacing （S/m） of subsurface pipes can be expressed as N=11.872-7.385D+0.237S. Under well-drained conditions， i.e. drain spacing at 30 m and depth at 1.2 m， the predicted soil desalination （salt content lowered to 1 g/kg） time is about 10 years. While drainage intensity is increased by reducing drain spacing to 20 m， the desalination time is reduced to 8 years. Under poor drained conditions （drain spacing is more than 100 m）， the predicted soil salinity remains high even after 10 years of drainage leaching. According to different desalination goals， the subsurface drainage system can be designed reasonably to accelerate the desalting process of soil in coastal reclamation areas and provide reliable land resources for the local agricultural development.

For the analysis of important position near the hole of the influence of the centrifugal pump cavitation performance， with a low specific speed centrifugal pump as the research object， the CFD simulation software is used based on RNG k-ε turbulence model to full port steady turbulent flow cavitation model numerical simulation， study in blade cavitation primary position， opening area， open hole shape affect the performance of centrifugal pumps. It is found that for the low specific revolution centrifugal pump in this paper， too large opening area will cause energy loss. When the hole type is quincunx hole， too small an opening area will aggravate impeller cavitation. The cavitation performance of the centrifugal pump is significantly affected by different hole areas and different hole types. When the hole area is 1/4 \mathrm{\pi } mm² and the hole type is square， the head increases by 9.8% and the anti-cavitation performance of the centrifugal pump is significantly enhanced. The low pressure area at the inlet of the impeller is truncated and distributed intermittently when the hole type and hole area could effectively inhibit the impeller cavitation. When the hole area is 1/4 \mathrm{\pi } mm²， the hole type is square hole and the hole area is 25/4 \mathrm{\pi } mm²， and the hole type is quincunx hole， the turbulent kinetic energy of the centrifugal pump is significantly reduced， the energy loss caused by the original model cavitation is reduced， and the cavitation in the impeller is effectively inhibited.

In order to scientifically predict groundwater depth and promote the sustainable utilization of water resources in people's victory canal irrigation district， according to the complex characteristics of nonlinearity and non-stationarity， the accuracy of prediction is usually not high， Based on CEEMD， it has the ability to smooth non-stationary signals and BP can approximate arbitrary functions， has good nonlinear mapping capabilities， and has an advantage in the prediction of uncertain factors， the CEEMD-BP coupling model is built to predict the groundwater depth in the irrigation area. The results show that the CEEMD-BP coupling model and the EEMD-BP model have better prediction results than the BP model. The average relative error is 4.7%， the Nash coefficient is 0.96， and the prediction accuracy is higher. In conclusion， the model has high prediction accuracy， provides an effective method for predicting the buried depth of groundwater in the irrigation area.

In order to effectively guide Chinese cities to improve domestic water efficiency， the concept of benchmarking management is introduced to establish the benchmarking system of China’s urban domestic water use efficiency to conduct a systematic evaluation according to general statistical characteristics of normal distribution. And double logarithmic model is established and applied to quantitatively evaluate the extent and trend of the two key factors’ effect including water price and per capita disposable income. The result shows that China’s urban average per capita domestic water consumption keep stable with a slight decline， mainly benefiting from the increase of water use efficiency of those cities with relatively low water use efficiency or rich water resources. There is a significant difference in per capita domestic water consumption among China’s cities， but this difference shows a narrowing trend. Income elasticity keeps stable， and when the per capita disposable income rose 10%， per capita domestic water consumption will increase by 7%. While price elasticity declined from -0.484 in 2009 to 0.187 in 2013 showing a trend of decreasing， which means the impact of urban water price fine-tuning on domestic water consumption gets smaller. In order to better play the role of water price mechanism in water resource allocation， we need to promote the reform of water price policy.

In order to explore a universal long-distance booster chlorination scheme， a series of comparison experiments of one-time chlorination and booster chlorination under different initial chlorine concentrations is carried out， the residual chlorine decay and production of two typical disinfection by-products chloroform （CHCl₃） and dichloroacetonitrile （DCAN） are compared and analyzed for the drinking water in two water treatment plants with different water qualities. The results show that when the total chlorine demand of water distribution system（WDS） is less than 1 mg/L， the finished water can be disinfected by a single injection of chlorine； when it is higher than 1 mg/L， booster chlorination is recommended， and the booster chlorination stations should be set in the pipeline network when the residual chlorine decays to about 0.2 mg/L. Compared with one-time chlorine injection， the decay time extension rates of residual chlorine from two water works are 9.5%， 13.8%， 15% （WTP1） and 12.5%， 16.7%，22.9% （WTP2）， respectively. In the case of booster chlorination， the total yields of CHCl₃ decreases by about 12%~25% and DCAN by about 8%~18%， respectively. Booster chlorination can significantly reduce the attenuation of residual chlorine， effectively reduce the formation potential of carbonaceous disinfection by-products （C-DBPs） and nitrogenous disinfection by-products （N-DBPs） in WDS. Moreover， when the chlorine demand is higher and the water quality is worse， the advantage of Booster chlorination is more obvious than that of water with good water quality， but the overall change of DBPs is similar. When the dosage ratio of initial to booster chlorine is 1∶1， the residual chlorine in the pipeline network remains the longest， and has the best uniformity. In addition， the control effect on the generation of CHCl3 and DCAN is optimal. The conclusion still holds as the total chlorine demand changes. Choosing 1∶1 is recommended as the optimal ratio between the initial and booster chlorine dosage.

The water supply projects are exposed to highly corrosive environment in the old revolutionary base areas such as Shaanxi， Gansu and Ningxia. The effects of different water-binder ratios， cement types， gas content， admixtures and their ratios on the durability of concrete performance are studied， such as strength， impervious resistance， frost resistance， carbonization resistance， chloride ion and sulfate erosion resistance. The results show that when the water/cement ratio is 0.31/50%， the mix proportion of ordinary Portland cement， mineral powder and fly ash is 5∶3∶2， the comprehensive performance of the durability air-entraining concrete is optimal. The design index （56 d） can achieve C40F200W8KS150， impervious resistance grade is more than W12， 60 d rapid carbonization depth is less than 20 mm， frost resistance grade is over F200， and carbonation resistance can meet the atmospheric environment （carbide） 50 a durability requirements. Meanwhile， the design service life level is 100 a under sulphate environment （Y3） or chlorine environment （L2）.