In view of the numerous hidden dangers and frequent dangers of dike projects in China， based on the characteristics of dike project construction and the needs of flood prevention and disaster reduction strategies， the design and implementation of a dike project safety management platform based on GIS+BIM+IoT digital twins is studied based on GIS， BIM， and IoT. The integrated digital twin technology is combined with the dike safety management， the digital twin data and model integration and visual expression methods are studied， the dike danger recognition deep learning model is established， and the dike engineering safety management platform based on the GIS+BIM+IoT digital twin is designed. The typical dike section of the Yangtze River main dike is selected for application demonstration. Compared with the problems of lack of information， insufficient accuracy， lagging feedback， and single expression in the past dike project database management or two-dimensional management mode， practice has proved that the safety management platform of dike engineering based on digital twins can realize the integration and interaction of spatial geographic data， BIM model data， and IoT data in various environments for simulation， decision-making， optimization， adjustment and visualization， its risk recognition effect is better than the traditional model. The research and design of the platform can carry out real-time monitoring， diagnosis， analysis， decision-making and prediction of the safety management of the dike project， realizing intelligent operation， precise control and safe operation and maintenance.

Targeted at the reality of weak technology and limited defense facilities in grassroots department of Guangdong Province， this paper proposes a new model for defensing mountain flood disaster based on “one map and one manual”. Based on GIS mapping theory， through map synthesis methods such as symbol thinning， map representation， and marker dispersion etc. This paper completes making defense maps and defense manuals of mountain flood disaster for 7 cities at county-level and town-level， this would promote the formation of “one map and one manual” mountain flood disaster defense system at the grassroots. At the same time， a WebGIS-based defense atlas information management system is developed， which provides a unified data access and security control mechanism， realizes the functions of visual display， dynamic management， online update and traceability of various data， and helps to ensure the authenticity， accuracy and real-time of data. The results can effectively break through the terminal blockage of information transmission， solve the problem of passive decision-making in the “last mile”， promote the full sharing of data resources for mountain flood disaster defense operations， and strengthen the defense capability of mountain flood disasters at the grassroots level.

This paper proposes a way to explore the relationship between the combination of water quality indicators and the accuracy of river dissolved oxygen prediction. First， the XGBoost model is used to calculate the water quality index feature importance score， and then based on the greedy rule and the water quality index feature importance score， 8 water quality index combinations are arranged. Finally， the BP neural network is used to predict dissolved oxygen for the 8 water quality index combinations. Experimental results show that pH， water temperature， conductivity， and ammonia nitrogen are the four key indicators that affect the prediction of dissolved oxygen. Among the 8 combinations of water quality indicators arranged， pH， water temperature， conductivity， ammonia nitrogen， turbidity， and CODmn are the most accurate combinations of input indicators for the prediction of dissolved oxygen. Experimental analysis by exhaustively enumerating all water quality indicator combinations proves that the method is effective and feasible with lower time complexity， and can be used to select a combination of input indicators with high accuracy of dissolved oxygen prediction to improve the accuracy of dissolved oxygen prediction.

To scientifically evaluate the implementation effect of the river chief system and provide a research idea for the evaluation of the implementation effect of the river chief system，taking Huai'an City as the research object， 21 indicators are selected from the perspectives of economic， social， ecological， cultural and watershed management effects to construct an evaluation model of the implementation effects of river chief system. The subjective weights are determined by the sequential relationship method （G1）， the objective weights are determined by the entropy weight method （EVM）， the combination weights are obtained by the game theory combination assignment method， and the G1-EVM-SPA based evaluation model of the implementation effect of the river length system is constructed by combining the set-pair analysis method （SPA）， and the time dimension is selected from 2017 to 2020 to evaluate the effectiveness of the implementation of the river chief system and the degree of coordinated development in Huai'an over the past four years since the full implementation of the river chief system. The results show that the implementation effect of the river chief system in 2017 is moderate， and the implementation effect in 2018-2020 is good， and the trend is improving year by year. The coordination development degree of the implementation effect of the river chief system in 2017-2020 is 0， 0.501 8， 0.484 5， and 0.497 3， respectively. Except for 2017， which is under the highly uncoordinated grade， the coordination development degree grades in 2018-2020 are under the critical coordination grade. The overall coordination development degree is improving year by year.

In order to analyze the mechanism of the siltation of urban river in Changzhou， this paper uses the method of dimensional analysis and water channel experiment to study the influence of bank slope angle， flow ratio and density Froude number on the scour of the confluence area during the process of tributary river flowing into the mainstream river. In this study， the confluence angle of tributary flume and mainstream flume is set at 90°， and four different bank slope angles （45°， 60°， 75°， 90°） are compared with different flow ratios and density Froude numbers. The results show that the smaller the ratio of flow in tributary to the flow of the main stream， the greater the influence of the bank slope angle on scour depth is. For any given density Froude number， the smaller bank slope angle can lead to the smaller scour depth. According to the two empirical relations obtained by fitting， the influence of the bank slope angle on the height of sediment deposition is more than that on the scour depth， and the density Froude number has the greatest influence on dimensionless scour depth， and the bank slope angle has the greatest influence on the dimensionless sedimentation height.

In order to determine and analyze the groundwater ecological level in Changling County， a total of Landsat 8 series remote sensing images from 2013 to 2017， buried depth data of 51 groundwater observation wells and 47 phreatic salinity detection data in 2017 are collected. Based on the field investigation and laboratory experiment， the spatial and temporal changes of groundwater level and vegetation coverage in the study area from 2013 to 2017 are determined by using remote sensing technology （ENVI） and geographic information system （GIS）.Through the analysis of the vegetation coverage ratio （FVC） and the relationship between the groundwater depth and diving salinity， the appropriate growth of vegetation in the study area of diving level and diving salinity water is determined： the results show that from 2013 to 2017 in the average groundwater level and vegetation cover degree decline year by year， the study area northwest shallow depth of groundwater， vegetation cover degree better； In the central and eastern regions， the groundwater depth is larger and the vegetation coverage degree is poor. When the depth of local groundwater is 3.3~4.5 m and the phreatic salinity is less than 0.85 g/L， the ecological water level and phreatic salinity are suitable for vegetation growth in the study area. When the depth of local water is less than 3m， soil salinization occurs in the surface soil near the lake marsh. When the depth of local water was greater than 8.4m， the phenomenon of soil desertification appeared in some areas of central China.

To determine the friction characteristics of the interface between the ecological bag and riverbank slope soil， the direct shear test of the interface between the ecological bag and riverbank slope soil is carried out with the ecological bag used for river bank slope treatment as the test material， and the effects of soil dry density and water content on the friction characteristics of the interface between the ecological bag and riverbank slope soil are analyzed. The results show that the shear strength of the interface between soil and ecological bag decreases with the increase in water content， and increases with the increase in the dry density of soil. At the same time， the interface friction coefficient between the ecological bag and slope soil decreases with the increase in water content and increases with the increase in soil dry density. In addition， under the same conditions， the friction coefficient between sandy soil slope and the ecological bag is smaller than that of cohesive soil slope. The research results have a certain reference value for the application of ecological bag slope protection technology in river ecological treatment engineering.

The hydrodynamic and water quality model of Guangzhou-Foshan Pearl River tidal river network is constructed based on EFDC， the model is calibrated and verified by the monitoring data of water quantity and water quality of 4 important control sections and 113 important primary tributaries， and the response relationship between pollution discharge of primary tributaries and water quality of control sections is established. The model quantifies the contribution rate of each tributary to the water quality control section， and takes the water quality improvement target of the important section as the constraint， obtains the allowable discharge value and reduction quantity of the main primary tributaries through the optimization solution of the model， determines the improvement target of the tributary， and provides important technical support for the diagnosis and identification of pollution problems， the improvement of hydrodynamic conditions and the promotion of water environment quality.

The concept of temporal stability embodies the spatial pattern of soil moisture persist with time. Hence， measurements at the representative points can reflect the mean soil moisture of the watershed. This method facilitates the estimation of soil moisture at watershed scale. This paper analyzes the characteristics of soil moisture temporal stability at different depths in Babaohe Watershed in the upper reaches of Heihe River. The representative points to reflect the mean-watershed soil moisture are located. Then combining the soil， vegetation and topographic conditions of the watershed， the key factors that control the temporal stability of spatial soil moisture distribution are investigated. The results show that most of the representative points are located at the area covered by dominant vegetation and main soil type. The representative points in Babaohe Watershed are No.23 and 13 at the depth of 5 cm， No.47 at the depth of 10 cm， and No.37 at the depth of 20 cm. The temporal stability increase with the depth in the vertical direction. The main controlling factors of the soil moisture temporal stability in this basin are the vegetation and soil type. In the area covered by the alpine grass and carex steppe， and brown and black felt soils， it is easier to obtain the average surface soil moisture above the depths of 10 cm. This study can provide a theoretical reference for the soil water estimation at watershed scale， and a scientific basis for optimizing the design of observation network of watershed soil moisture.

In order to improve the flood control capacity of cascade reservoirs in the Dadu River Basin， Dagangshan Reservoir is considered as the main study object to analyze the problems of the current reservoir operation mode. After setting up different inflow scenarios， and analyzing the flood control capacity of cascade reservoirs， the hydrometeorological forecast accuracy of Dagangshan Reservoir， and the safe discharge of the downstream channel， the cascade flood routing algorithm and the improved pre-discharge capacity constraint method are respectively used to study the flood control operation index of Dagangshan Reservoir under the condition of cascade joint operation and the dynamic operation index under the condition of small inflow， based on which the Dagangshan reservoir operation scheme in the flood season can be formulated. According to the flood routing calculation based on the typical flood process， the flood-peak discharge can be reduced by 530 m3/s when the inflow of Dagangshan Reservoir is large， which can reduce the flood control pressure of downstream section； when the inflow is small， the economic benefit of the Dagangshan Reservoir can increase by 6~9 million kWh based on the premise of ensuring its own safety， which improves the utilization of flood resources. In addition， due to scientific nature and rationality， the research method can provide reliable reference for the operation and management of reservoirs with similar regulation capacity.

The ecological protection and high-quality development of the Yellow River Basin cannot be separated from the rational allocation of water resources of the Yellow River. The Yellow River runoff plays a key role in maintaining global energy balance， water and sediment cycle， climate change and ecological environment evolution. Dams strongly change the spatial and temporal distribution of water resources and interfere with the natural rhythm of rivers. Xiaolangdi Dam is China’s second largest water conservancy project， the data of Huayuankou Hydrological Station before and after the operation of the dam are sorted out by using the Range （the Range of Variability that RVA）， Theil Sen slope， Mann Kendall mutation test and methods of wavelet analysis of the degree of the change of the Yellow River runoff， amplitude， point mutation and period. The decreasing trend of annual runoff passed 99% significance test， which was the most obvious from 1998 to 2011， and the abrupt transition point appeared in 1990 and 2012. The runoff had obvious periodic changes， and the main period was lower than the contour center around 2000. The results of mutation test and wavelet analysis can predict that the annual runoff will be low in the future. During the period of water and sediment regulation， the siltation of many Yellow River sluice gate and diversion canal system is more serious due to the large amount of water， high sediment concentration and rapid water regression. The rule of runoff variation in the Yellow River is made clear， and the decision-making of dam operation management， regional territorial spatial planning and national economic development planning is adjusted， which can lay a foundation for ecological protection and high-quality development in the middle and lower reaches of the Yellow River.

In order to reveal and discuss the spatial dynamics and driving factors of vegetation coverage in Kashgar， Landsat series satellite data is used as the data source， based on the Normalized Differente Vegetation Index （NDVI） and pixel dichotomy model， ENVI 5.3 and ArcGIS 10.3 software is used to estimate the vegetation coverage of Kashgar， and the vegetation coverage from 1995 to 2020 is studied.The research results show that： ① The overall vegetation in Kashgar is mainly high vegetation coverage， and the medium and low vegetation coverage are relatively fragmented and distributed around the high vegetation coverage in the farmland protection forests around the city center and on both sides of the rural road； ② From 1995 to 2020， the vegetation coverage and coverage area of Kashgar City showed an increasing trend. In 2020， the vegetation coverage area increased by 172.6 km² compared with 1994， an increase of 36.3%. ③ The regional and time-based improvement and degradation of vegetation coverage in Kashgar will coexist. In terms of time period， the degradation is obvious from 2010 to 2015， and the area of improvement was the largest from 2015 to 2020. Regionally， the urban area is the most degraded， and the four townships in the east have improved the most. The total and high vegetation coverage centroids move linearly to the four townships in the east by 6.39 km and 8.69 km， the migration speed of the above two centroids accelerated significantly from 2010 to 2020； ④ The increase in precipitation and temperature in Kashgar City， combined with the acceleration of urbanization and frequent human activities are the main reasons for the changes in vegetation coverage in recent years. Among them， the increase in the area of forest land and arable land contribute the most to vegetation coverage. It can be seen that this paper can provide a scientific reference for the ecological environment and sustainable development of Kashgar.

The central region is an important economic hub in our country， but the problem of “central collapse” makes its sustainable development lack of power. In order to explore the relationship between resources and social and economic development in the context of high-quality development， this paper takes the five development concepts as the baseline layer to construct the green development index， which is taken as the expected output， and uses the SBM model to calculate the water resource utilization efficiency in the central region from 2003 to 2018. Finally， the Tapio decoupling model is used to explore the relationship between social and economic development and water resources in central China at different stages. The results show that the interannual fluctuation of water footprint in the central region is obvious， reaching the maximum value of 683.54 billion m3 in 2015. The green development index of all provinces showed a steady upward trend， and the spatial difference was the least in 2008. The mean value of water resource utilization efficiency in the central region reached the peak in 2006， and Shanxi and Hubei reached the highest value. The decoupling relationship between water resources and economic and social development gradually improved over time， indicating that water resources utilization in central China gradually met the requirements of high-quality development of the country. This paper has certain guiding significance for the high quality development of the central region.

Under the context of global warming， to understand the response of snowfall to climate change， the double temperature threshold method is used in this paper to extract snowfall series， based on daily meteorological data from 43 meteorological stations in the Haihe River Basin from 1960 to 2016. In addition， the spatial and temporal variation characteristics of snowfall are analyzed according to the snowfall levels as determined by the national meteorological departments. The results show that ① the snowfall at each meteorological station can be effectively estimated at annual scale through the snowfall identification index equation， for which the correlation coefficient in the periodic and verification periods is above 0.90 and the relative error is within ± 5%. ② In terms of the time distribution， the interannual variation of snowfall at different levels shows a less obvious decreasing trend， but the interannual variation trend of each geomorphic type area is different. ③ In terms of the spatial distribution， the meteorological stations in Taihang Mountain Area and plain areas show a decreasing trend， while those in Yanshan mountain area and coastal area show an increasing trend. ④ By analyzing the correlation between snowfall and temperature and the temperature at different levels of snowfalls， it is found that heavy snow and Blizzard are positively correlated with temperature， while moderate snow and light snow are negatively correlated with temperature， and the temperature of snowfalls in plain areas is the highest and the lowest in Yanshan mountain areas.

In order to explore the forecasting method which is more in line with the flood control requirements of the middle and small river basin and improve the accuracy of flood forecasting， taking Tunxi Basin as an example， combined with the actual flood forecasting requirements of the middle and small rivers， a non-equal-weight parameter calibration method with the qualified rate of flood peak and the qualified rate of flood peak onset time as the main constraints is adopted （i.e.， the weights of runoff depth， flood peak discharge， qualified rate of peak onset time and deterministic coefficient in the objective function are respectively （1∶2∶2∶1） to calibrate the parameters of the Xin'anjiang River model， and use the arithmetic mean method to couple the calculation results of the Xin 'anjiang River model and BP neural network model so as to improve the accuracy of flood prediction. The results show that the method based on the main constraints of flood peak discharge and peak occurrence time is feasible in the flood prediction of Tunxi Basin. Compared with the traditional equal-weight method， the method has more advantages in the flood peak and peak occurrence time prediction， and meets the flood control requirements of small and medium-sized rivers. The Xin 'anjiang River model can simulate the flood peak and peak time well， and the BP neural network model can simulate the flood peak and runoff depth well. The arithmetic mean method is used to couple the simulation results of the two models can improve the accuracy of flood prediction.

The fourth Jiangdu Pumping Station adopts BYKD type hydraulic blade full regulating device， which has caused many problems， such as oil leakage， burning bearing bush and the aging of accumulator skin. The South-to-North Water Diversion Project is under the condition of full load operation with large flow water delivery， and it does not have the conditions for shutdown and maintenance. Therefore， the emergency scheme for depressurization operation is designed to reduce the amount of oil leakage， extend the interval of oil replenishment， and ensure the operation of main engine. In order to solve the problems of complex oil circuit， large amount of pipeline joints， many oil leakage points and burning of bearing bush caused by centralized oil supply mode of external oil supply system. The transformation of built-in blade adjusting mechanism is designed and implemented， the lower piston into the upper one is changed through the comparison and calculation of piston adjusting force， adjusting rod tension and connecting bolt tension， the transformation points are made clear. In this scheme， micro motor， micro gear oil pump and oil cylinder are integrated into the blade adjusting mechanism， which simplifies the structure of the blade adjusting system， makes the oil circuit independent， enhances the sealing performance and improves the reliability of the blade adjusting mechanism.

In view of the technical problem that it is difficult to obtain the dynamic characteristic equation of the main engine unit of most pumping stations in China， a method is proposed to obtain the dynamic characteristic equation of the main unit of the pumping station through the comprehensive characteristic curve of the model operation provided by the manufacturer of the main unit of the pumping station. Firstly， the discrete characteristic data is obtained through the comprehensive characteristic curve of the model operation， and then the dynamic characteristic equation of the main unit model of the pumping station is formed by the double multiplication fitting. Secondly， the static operation data samples are obtained through the real computer monitoring historical database and the cloud database of the pump station operation management， and the static point correction is carried out by using the cubic index matrix data processing method. Finally， the extension theory and neural network calculation method are combined to create an extension neural network training method to realize the dynamic correction of the dynamic characteristic equation of the original main unit of the pumping station， and the method has the characteristics of self adaptability， self-learning habit and extension. The application practice shows that the innovative combination of the cubic index matrix data processing method and the extension neural network training method can accurately， effectively and reliably obtain the dynamic characteristic equation of the main unit of the pumping station， which provides a scientific decision-making basis for the safe and reliable operation of the whole pumping station， the combined dispatching of the main units and the optimal load distribution.

In order to improve hydraulic performance and ensure stable operation of Zhuji Pumping Station， an optimization design of the inlet conduit and outlet conduit is completed based on three-dimensional turbulent flow numerical simulation. The experimental research on the hydrodynamic characteristics of optimized pump system model is carried out on a high-precision hydraulic machinery test bed. The experimental results show that the flow velocity of the inlet and outlet conduit of Zhuji Station changes uniformly and the hydraulic loss of the conduit is small， the highest efficiency of the pump system model is 78.33%， and the hydraulic performance is excellent. Compared with the pump section， the optimal operation point of the pump system model is offset by about 2° to the negative angle and the small flow area. Secondly， when the inlet pressure of the pump system model is equal to the value of critical net positive suction head， the larger zones of cavitation bubbles are observed on the pressure side and suction side of the blades. Thirdly， the shaft frequency and blade passing frequency have greater influence on the pressure pulsation amplitude at the inlet and outlet of impeller， and they have less influence on pressure pulsation amplitude at the outlet of the guide vane. In order to avoid resonances， the natural frequency of the pump structure should avoid the pump shaft frequency， blade passing frequency and its frequency multiplication.

To explore the effects of water-biogas slurry integrate irrigation methods under the condition of alternate partial root-zone irrigation （APRI） on the growth， yield and quality of tomato， two irrigation methods， surface irrigation （APRI-B） and hole irrigation （APRI-X） are adopted in two-season pot experiments. The results show that the irrigation method has significant influence on the growth， dry biomass distribution， yield and quality of tomato， such as APRI-X can promote the increase in plant height and stem diameter of tomato， as well as the photosynthetic rate and the formation of photosynthetic product. When compared with APRI-B， the method of APRI-X can improve the root dry biomass more than 23% and promote the roots to grow better into the deep soil and obtain a superior root-shoot ratio. Furthermore， the yield and water use efficiency （WUE） of APRI-X treatment are much higher than that of APRI-B， and the titratable acid， total soluble sugar， vitamin C， soluble protein， soluble solid and fruit firmness of tomato in APRI-X treatment are also better than that of fruits in APRI-X treatment. This indicates that the irrigation method of APRI-X can improve the taste and quality of tomato， as well as the quality for storage and transportation， which will be a good method for water-biogas slurry integrated irrigation in agriculture production.

To alleviate the effect of soil secondary salinization on agricultural sustainable development， this paper explores the temporal and spatial distribution of soil water and salinity and topsoil salt accumulation under well drainage combined irrigation. The basin experiment is conducted to address the temporal and spatial distribution of soil water and salinity under the well drainage combined irrigation， canal irrigation and combined groundwater and surface water irrigation. The field experiment is implemented to analyze the temporal and spatial distribution of soil water and salinity along well radial distance. The appropriate groundwater depth and soil water content and salinity are maintained by the combined groundwater and surface water irrigation， and the groundwater depth and soil water content and salinity are 1.6~5.0 m， 10%~25% and 300~500 μS/cm respectively. Groundwater depth decreases along the well radial distance， and groundwater drawdown decreases by 0.35 m with the radial distance increase of 100 m. Soil profile salinity increases along well radial distance， and accumulated soil salts show a weak relationship with the groundwater depth. The well drainage combined irrigation has the potential to maintain the water and salinity balance and agricultural sustainable development， and reduced well spacing can attenuate salt accumulation because of salt leaching reduced by shallow groundwater depth far away from the well.

Saline soil developed on sedimentation in the Yellow River Delta has compact structure， high bulk density， and low permeability， which leads to the difficulty of salt leaching. This study analyzes the effects of sand-incorporation rates （0%， 20%， 50%） on soil salt leaching by indoor soil column experiment. The results show that sand-incorporation can significantly increase the speed of salt leaching， shorten the leaching time， and reduce the electrical conductivity of leaching solution under the same leaching volume. With the increase in sand-incorporation rate， the desalination rates of K⁺， Mg²⁺ and Cl^- after leaching have no significant variation， the desalination rates of Na⁺ and Ca²⁺ have increased， the desalination rate of SO₄ ^2- has reduced， the total salt desalination rate has increased， and the better the ion composition of soil. The pH of soil has increased significantly after leaching， which leads to soil alkalization， but the higher the sand-incorporation rate， the less the increase of pH， the lower the degree of soil alkalization. Sand-incorporation can significantly reduce the SAR of soil， and the more the sand-incorporation rate， the lower the SAR of soil after salt leaching. The results will provide a theoretical basis for the improvement of saline soil in the Yellow River Delta.

The aqueduct body is a thin-walled structure， and its temperature field and temperature stress variation are quite different from those of mass concrete structure. Large aqueduct is made of high strength concrete， which has fast heating speed and high heating value in the early stage. It is easy to have large temperature difference between inside and outside in the early stage of pouring. If the outside temperature is very low at this time， it is very easy to cause the tensile stress on the surface to exceed the tensile strength of concrete， resulting in surface temperature cracks. The temperature field and thermal stress of Shahe aqueduct are simulated by ANSYS， and the causes of cracks in the inner side wall of Shahe aqueduct are analyzed. The results show that the main reasons for the cracks in the inner side of aqueduct side walls are the excessive temperature difference between the inside and outside of aqueduct side wall concrete， the rapid cooling rate and the strong restraint at the intermittent surface. According to the causes of cracks， the temperature control measures are put forward and verified to be reasonable， so as to avoid the generation of temperature cracks in the subsequent tank body and create conditions for the smooth progress of the project.

Accurate water consumption prediction is an important starting point for responding to the country’s high-quality development， and it is also the basis for the optimal allocation of urban water resources. In view of the volatility of the water consumption sequence and the linear relationship between the gray model and the required factors， this paper proposes a GM-LSSVR prediction model based on HP filter decomposition， that is， the gray correlation analysis method is first used to screen suitable water consumption influencing factors. And then the HP filter decomposition method is used to decompose the selected water consumption and influencing factors into a long-term trend sequence and a short-term fluctuation sequence， and finally the GM-LSSVR combined model is used to predict water consumption. Taking Zhengzhou City as an example， the model is used to predict water consumption from 2001 to 2019， and compared with the prediction results of the GM（1，N） model and the BP neural network model. The results show that the prediction accuracy of the GM-LSSVR prediction model based on HP filter decomposition is greatly improved， and it is feasible and practical， and can be better applied to the study of urban water consumption prediction.

To address the problem that the data-driven pipeline leak detection method fails to effectively utilize the spatial and temporal characteristics of the leak signal simultaneously， a pipeline leak identification method based on a combination of one-dimensional convolutional neural network （1D-CNN） and long short-term memory network （LSTM） is proposed. The network model takes the de-noised pipeline pressure signal as the input source， the spatial and temporal dimensional features are extracted by using 1D-CNN and LSTM successively and the correspondence is established between the pressure signal and the pipeline condition by using the spatio-temporal features extracted in two different dimensions， thus realizing the detection of pipeline leaks. The experimental results show that the features extracted by the 1D-CNN-LSTM method are more effective and reliable， and the accuracy of pipeline leak detection is significantly improved.

Based on the current situation and problems of performance management in hydraulic engineering，this paper takes Beijing as an example to built the output quality indicator system in the performance evaluation. Operation and maintenance are divided into seven parts， including water management， operation， security， inspection， emergency rescue， safety monitoring and maintenance. Index score is analyzed according to Delphi method，“one vote veto”and “ threshold rule”. The indicator system can not only make the index comparable and measurable but also enhance the operation and maintenance level in hydraulic engineering.

Through research， the evaluation method of seawater pumped storage resources and the site selection principle of power station is mastered. In view of the special problems brought by the marine environment， such as seawater corrosion， biological adhesion， reservoir water leakage， typhoon and salt fog， research is done on common key technologies for the design of hydraulic and electromechanical equipment. An empirical platform is built to study the dynamic characteristics and control strategy of variable speed units. A complete set of key technical schemes are formed and guidelines for seawater pumped storage power station are designed to guide the construction of subsequent projects. This paper systematically expounds the main problems， solutions and research results faced by the design of seawater pumped storage power stations from the perspectives of resources evaluation and restriction principle research， hydraulic structure design and electromechanical design so as to form a complete set of key technical schemes supporting engineering design and fill the technical gap of seawater pumped storage power stations in China.

Relying on the national key R&D program research on Forward-looking Technology of Seawater Pumped Storage Power Station， and considering the particularities of seawater environment and sea boundary， such as high corrosion of seawater and marine fouling microorganisms， this paper analyzes the protection conditions of the main parts of hydraulic structures of seawater pumped storage power stations， proposes the protection scope and applicable conditions of hydraulic structures and requirements for scientific research achievements.

Compared with conventional pumped storage power station （PSPS）， the working medium of seawater PSPS is seawater. So two new problems arise with hydraulic machinery auxiliary system： anticorrosion and antipollution. In terms of anticorrosion， the corrosion risk from the system design is reduced first， then materials through reasonable economic and technical comparison are selected， and finally the corrosion resistance of materials through appropriate anticorrosion measures is improved. In terms of antifouling， due to the small diameter and many buried pipes of the hydraulic machinery auxiliary system， the conventional coating antifouling cannot achieve sustainable effects easily. This paper uses the antifouling technology of coast nuclear power plant for reference and adopts the antifouling scheme of electrolytic seawater. After clarifying the key points of basic anticorrosion and antifouling. According to the characteristics of each auxiliary system of hydraulic machinery， this paper finally completes a complete set of anticorrosion and antifouling scheme results.

Pumped storage power station has great development prospects. Due to the special conditions of marine environment， a pumped storage power station in the island is facing various problems. This paper takes the underground plant in the site of a southern island as an example to introduce its designing philosophy of ventilation system， ventilation process， salt spray control and confronted problems. Besides， it analyzes countermeasures for problems from the aspects of air process， air speed and air intake to provide references for the design of ventilation system of the pumped storage power station in the island.

With the rapid increase in the demand for water，for urbanization and people’s livelihood， reservoir dispatch is facing huge challenges. The dispatch strategy that takes into account the people’s livelihood and the demand for power generation water has become an important soft technical means to ensure the efficient operation of the project. The NSGA-Ⅱ algorithm is used to establish a multi-objective optimal scheduling model for reservoir operation， to carry out research on the scheduling strategy after the demand of the reservoir changes， and to measure the pros and cons of the reservoir scheduling strategy by the level of water shortage. According to the comprehensive optimal goal， under the premise of giving priority to the protection of people’s livelihood water， the operation scheduling strategy can not only increase the power generation， but also reduce the dependence on natural water resources after major changes in water demand， and improve the efficiency and utilization of the reservoir to achieve the research goal of improving the economic benefits of the overall project.

The three-dimensional finite element method is used to analyze the stress of crescent-rib bifurcation with waistline turning angle of zero degree and the influence of waistline turning angle on the stress of the wall and crescent-rib of bifurcation. The results indicate that waistline turning angle has little effect on the stress of the crescent-rib. The design scheme with waistline turning angle of zero degree reduces the stress in the obtuse angle area and improves the stress of the bifurcation. Keeping the wall thickness of basic cone unchanged， the ability of bifurcation to bear internal pressure can be improved by increasing the wall thickness of transition pipe. Because the waistlines of the main cone pipe and the branch cone pipe are collinear， the fabricating difficulty and error can be appropriately reduced during assembly， which can be used in engineering design.

Dagu Hydropower Station is located in the high altitude area with complex climate environment. Temperature control and crack prevention during construction are the key technical problems in the design and construction of the project. In this paper， 5# slope dam section is selected as the research object to simulate the whole process of dam pouring. Considering the concrete creep， the three-dimensional finite element method is used for numerical simulation calculation. The temperature field and stress characteristics of the dam are studied， and the temperature control and crack prevention measures are proposed. The research results show that RCC dam construction in the high altitude area has the characteristics of high risk of cracking on upstream and downstream dam surface when concrete is poured in low temperature seasons and high risk of cracking in internal concrete when concrete is poured in high temperature seasons. After adopting the temperature control and crack prevention measures proposed in this paper， the temperature variation of upstream and downstream dam surface and warehouse surface is significantly reduced under the combined action of external temperature maintenance and internal water cooling. The anti-crack safety degree of concrete on the surface and inside of the dam body can reach 1.8， which meets the engineering design requirements.

In view of the adverse influence of fishway vertical slot size error on fish passing efficiency caused by construction technology and other reasons in practical engineering， the physical model tests of a vertical slot narrowing are carried out to study the induced changes of hydraulic characteristics of the fishway. The experimental results show that the water depth of the upstream side of the vertical slot increases and backwater curve is formed when a vertical slot is narrowed. The influence range can cover 5~15 ponds. The water depth of the downstream side of the vertical slot decreases sharply and then recovers quickly， covering only 1~2 ponds. When the slot width reduces by 40% （k=0.6）， the maximum rise of the upstream water surface line is 8 cm （in prototype）， so its impact on the actual project is limited. The flow velocity at the narrowed vertical slot increases significantly （k=1.0， v=1.1 m/s； k=0.6， v>1.6 m/s）， but the velocity of upstream adjacent vertical slot decreases slightly （<10%）， and the velocity of downstream adjacent vertical slot has no significant change. The velocity v of the narrowed slot increases in power exponent with the decrease in the narrowing coefficient k， it tends to form velocity barriers. Based on the burst velocity of the fish passing through， the narrow range of vertical slot of the fishway should be controlled within 16% and 29% respectively， for the fishway passing objects of the four major Chinese carps and plateau Schizothorax Species.

At this stage， China’s water conservancy engineering group is still based on manual experience. Due to the lack of scientific analysis of the time lag of water flow， it is difficult to meet the urgent needs of intelligent regulation in the new era. The Zhentouba I~Shaping II section is located in the Dadu River Basin， with steep slopes and difficult hydraulic control research. At present， the hydraulic control plan is mainly based on manual experience. Taking this area as an example， this paper uses a one-dimensional unsteady flow numerical simulation model to systematically analyze the time lag of water flow， calculate the ideal flow process of the downstream boundary when the upstream flow changes and the downstream water level is stable， and a fast calculation method is proposed. The reliable hydraulic control method has been verified by hydrodynamic simulation， and the maximum water level fluctuation produced by the control method is about 0.2 m， which can ensure the safety of the river canal. Finally， based on the control method and the orthogonal test method of sensitivity analysis， a formula that can quickly generate the hydraulic control plan under different scenarios of the Shaping II Hydropower Station is constructed.

Based on the ME-Tennant method， this paper defines the ecological flow process level， and constructs an ecological operation model with the highest ecological flow process level and maximum power generation as the operation goal. The improved NSGA-Ⅱ algorithm is used to solve this model， which is used to repair the dewatering reaches of the downstream ecological degradation of the dam. The model is applied to the Kuaizilou-Shuikou Cascade Hydropower Station in Hunan Province， and the results show that the ecological flow and the power generation flow are in a competitive relationship. As the level of the ecological flow process increases， the power generation will also decrease. The power output of the selected reservoir scheduling schemes for the wet year， the normal year， and the dry year are 114.87， 84.44， and 61.39 million kWh respectively， the ecological flow process levels are all at the “very good” level， ensuring the power generation and meeting the high-level ecological water demand for the restoration of ecologically degraded rivers to a healthy state. The research results can provide reference for the ecological operation of reservoirs with ecological degradation problems.