In order to study the protective effect of plant in slope ecological bag support under heavy rainfall， this paper sets vegetation ecological bag support and non-vegetation ecological bag support respectively in two kinds of slopes under heavy rainfall in the model test. The volumetric water content and pore water pressure distribution at different positions of slopes （slope surface， slope top and slope bottom） during heavy rainfall are measured. The infiltration law of ecological bag slope protection under different conditions of heavy rainfall is analyzed. The results show that： ① In the case of ecological bag support without vegetation， the distribution of infiltration rates at different positions is slope surface > top of slope > bottom of slope. In the case of ecological bag support with vegetation， the infiltration rates at different positions are almost the same. And the overall rate is faster than that of ecological bag support without vegetation under the same conditions. ② The abrupt change rate of volumetric water content supported by ecological bags of vegetation becomes faster because the flow at the root-soil interface brings more rain water into the soil. ③ The overall increase rate of pore water pressure in the support of ecological bags with vegetation is slow due to the slow development of the transient saturated zone on the slope. The slow development of pore water is conducive to the stability of the slope. However， this effect is not obvious in higher slopes. The above conclusions have an important theoretical guiding value and practical significance for slope treatment and maintenance under heavy rainfall conditions with ecological bags. ④ Combined with the actual project and test results， a slope value range suitable for ecological bag support can be determined， and a rainfall hazard warning method for slopes under ecological bag support is proposed.

The Jinsha River Basin is an important basin for the hydropower in China and it is also the main runoff and sediment source area for Yangtze River. The spatial distribution and seasonal variation of typical heavy metals in sediments from Panzhihua Section of Jinsha River are studied in this paper. The adsorption/desorption capacity of cadmium （Cd） in sediments of Jinsha River basin and the influence of environmental factors are explored， and compared with the sediments of Wuhan section of Yangtze River. The experimental results show that the average concentrations of heavy metals in the sediments are V>Zn>Cu>Pb>As>Cd. Except for a few sections， the concentrations of six heavy metals in the sediments are the highest during the wet period. The average concentration of heavy metals in sediments of the main stream is higher than that in tributaries， and the average concentration of Zn， V， Cd and Pb gradually decreases from upstream to downstream. The adsorption and desorption of Cd in sediments from Panzhihua section of the Jinsha River and Wuhan section of the Yangtze River are similar. The adsorption capacity of Cd is greater than the desorption capacity in the both kinds of sediments. Compared with the sediment of Yangtze River， the adsorption rate of sediments from the Jinsha River is faster， but the equilibrium adsorption capacity of the sediments from the Jinsha River is similar， both of which are about 135 mg/kg. Turbulence has great influence on the process of adsorption and desorption of Cd. With the increase in turbulence， the contact area between sediment and Cd increases， which has increased the adsorption capacity of Cd on sediments. Temperature only affects the adsorption/desorption rate of Cd in sediments，while the adsorption/desorption capacity is not affected.

In order to reveal the content and distribution of heavy metals in agricultural areas of the Lijiang River Basin， the west main canal and its tributaries of Qingshitan Irrigation District are selected as the research objects in this paper. The content of heavy metals in the surface sediments （0~5 cm） of the main and its tributaries is determined， and the distribution characteristics and pollution status of heavy metals in sediments are analyzed. The potential ecological risk assessment is carried out. The pearson correlation analysis and positive definite matrix factor decomposition （PMF） are used to analyze the sources of heavy metals. The results show that the average contents of heavy metals in sediments in irrigation season and non-irrigation season are Zn>Cr>Pb>Cu>As>Cd>Hg， and the contents of heavy metals in sediments in main canals and tributaries， irrigation season and non-irrigation season are significantly different. The potential ecological risk of heavy metals in the sediments of irrigation canals is strong， Cd and Hg are the main pollutants， and the potential ecological risk levels of heavy metals in different seasons and direct tributaries are different. The sources of heavy metals in sediments of main and branch channels include industrial pollution sources， agricultural pollution sources and urban pollution sources. Among them， agricultural pollution sources accounts for 42.45%， industrial pollution sources and urban pollution sources accounts for 33.86% and 23.69%， respectively.

As China increases investment in water environmental governance， those rivers with the concrete bed in many cities in China are gradually transformed into natural rivers with abundant aquatic vegetation. And the flow regime is now with double- or multi-layer vegetation. So， it is with important research significance in the analysis of river flow pattern， determination of flood control elevation and the accurate analysis of pollutant migration to analyze the change of water dynamic in the multi-layer vegetation. Since the flow with double-layer vegetation is the basis of flow with multi-layer vegetation， the chacartor of flow with double-layer vegetation is taken as the research object in this paper. First， two groups of steel nails with different heights are used in the bed of the water channel to simulate the scene of double-layer vegetation. Then the velocity and Reynolds stress data are obtained from different scenarios， including the unsubmerged and submerged flow with double-layer vegetation， under the steady uniform flow state. Finally， based on the experimental results and the analysis of measured data， the law of flow velocity distribution and Reynolds stress distribution of floew with double-layer vegetation are trying to be found. The analytical solution of flow velocity distribution and stress distribution of flow with double-layer vegetation can be optimized and promoted to the thinking of the analytical solution of the flow with multi-layer vegetation. The result shows that the submerged and non submerged water flow with double-layer vegetation has different features in velocity distribution with different water depth intervals. And with analytical solutions， the vertical distribution of the average velocity of the water flow with double-layer vegetation and the trend of velocity distribution in the measured line away from the vegetation can be accurately predicted. Since the shear stress is composed of vegetation resistance， Reynolds stress and viscous stress， the magnitude of these three shear stresses is different from that of the total shear stress among different layers. So when analytical solutions are promoted from the flow with double-layer vegetation to that with multi-layer vegetation， the shear stress analysis of each water depth interval should first be analyzed for obtaining the main components of the shear stress in each layer. Then it can be feasible to part with small quantity for achieving the simplification of the momentum equation. The analytical solution of vertical velocity distribution of different water depth intervals with multi-layer vegetation can be finally obtained if all the steps above are done.

The monitoring points of water quality in Liaohe River Basin are limited， which cannot fully reflect the water quality status. The water quality is retrieved by remote sensing technology， which provides a scientific basis for the fine management of water environment. Based on GF1-WFV images， the maximum gradient algorithm is used to select pure water pixels， and parametric and non-parametric regression models are applied to retrieve TN concentration in the mainstream and some tributaries. The results show that： ①GF1-WFV images meet the inversion requirements in terms of dual resolution， imaging width and band setting， and the reflectivity in near infrared bands plays a key role in inversion from August to September. ②The inversion results of extreme gradient boosting model are better than stepwise regression and random forest model， R ² is higher than 0.575， RMSE is between 0.54~1.899， MAE is between 7.27%~26.99%. ③ In 2018， the TN concentration in the main stream and some main tributaries of Liaohe watershed is significantly higher from April to June than that in August to September， and the water quality in Qinghe River and Shenyang urban section of Hunhe River is inferior to that in Benxi section of Taizi River.

Groundwater is the main source of water in Dingbian area. In recent years， due to excessive exploitation of groundwater， a series of problems such as regional groundwater level decline， invasion of inferior water bodies， land desertification and so on have been caused， and even threatened the local water security. By means of field investigation and numerical model calculation， the typical area of dingbian area is selected to analyze the current groundwater chemical composition and distribution characteristics. Numerical simulation was used to calculate the migration of groundwater chemical components under different exploitation conditions in the water source area， and to explore the influence of groundwater exploitation intensity on the invasion of inferior water in the water source area. At the same time， the grouting curtain and hydraulic curtain are designed to explore a reasonable water source protection scheme. The results show that the phreatic water of the Quaternary Salawusu Formation is mainly SO₄·Cl-Ca·Mg type with low salinity. The phreatic and micro-confined water of Cretaceous Huanhe Formation is SO₄·Cl-Ca·Mg water with high salinity. Under mining conditions， the phreatic salinity of the fourth salawusu Formation increases， which may endanger the water quality safety of the water source. The stronger the groundwater exploitation intensity， the larger the area of Cl ion exceeding the standard in water source. Compared with grouting curtain scheme， the scheme of setting hydraulic curtain can effectively inhibit the invasion of inferior water and protect drinking water source. At the same time， it is necessary to control pumping and strengthen long-term observation of groundwater quality to lay a good foundation for water resources protection and sustainable development and utilization.

In order to clarify the influence of river water environment and hydrodynamic condition differences on the apparent characteristics of suspended particulate matter （SPM）， Niuwei River and Luanhe River in Haihe River Basin is selected as the research object， to identify the structural characteristics of SPM in the two rivers by microscopic morphology observation. The effects of water environment and hydrodynamic conditions on the apparent characteristics of SPM are further studied by simulated weathering experiments. The results show that Niuwei River has poor water environment and hydrodynamic conditions. SPM is completely wrapped by organic coating and has complex apparent characteristics. Luanhe River has good water environment and hydrodynamic conditions， there is only a small amount of organic coating on the outside， showing inorganic minerals inside out， with simple apparent characteristics. The results of weathering simulation show that under the same hydrodynamic conditions， poor water environment conditions can cause more organic loading of autobiotically SPM in Niuwei River and Luanhe River， while better water environment conditions can cause less organic loading. Under the condition of good water quality， organic coating content of natural SPM in Niuwei River decreases gradually with the increase in rotational speed， and Loss on Ignition （LOI） decreases to 0.12% when the rotational speed reaches 1 000 r/min. Water environmental conditions and hydrodynamic conditions jointly shape the apparent characteristics of SPM. Poor water environmental conditions are more likely to adhere to the surface of SPM， while strong hydrodynamic conditions are not conducive to the adhesion of the surface of SPM. The apparent characteristics of SPM in rivers are controlled by both water environment and hydrodynamic conditions， and are the result of both physical and chemical weathering. This paper is of great significance for understanding the apparent characteristics of SPM in rivers.

Wenchuan Earthquake has strongly changed the climate and underlying surface conditions around Zipingpu Reservoir. The frequent occurrence of secondary disasters and changes in the process of runoff and confluence prompted the dynamic adjustment of siltation characteristics in the reservoir area.Based on the measured topographic data since April 2008， the reservoir capacity change and sedimentation evolution process of Zipingpu Reservoir since the earthquake are analyzed. The results show that ①The M13 cross-section landslide barrier body divides the reservoir area into upper reservoir and lower reservoir. Before 2015， the reservoir area is mainly silted by dead reservoir capacity. After 2015， the upper reservoir regulation capacity decreases， and the lower reservoir dead reservoir siltation accelerates. ② The earthquake has greatly accelerated the siltation process of the reservoir， and the adjustment of the siltation distribution in the reservoir area is mainly affected by the evolution process of the barrier lake in the upper reservoir. ③ The earthquake has a great influence on the deposition distribution below 850 m and above 871.2 m， and has a little influence on the interval of 850~871.2 m. ④ Below the elevation of 830 m is the main body of siltation in the reservoir area， and the reservoir sections of dam~M13 and M13~M28 are the main locations of siltation. ⑤ The content of medium and fine sand accounts for 81.57% in the reservoir area， especially the fine sand seriously encroaches on the sediment storage capacity of the reservoir， which will have a negative impact on the benefit and flood control of the reservoir.

Due to the restrain of general layout， navigation structures， and other boundary conditions， the flow condition at the entrance area of approach channel is complicated， which hardly meets the navigation requirements. In this paper， based on the layout and river characteristics of Nianpanshan Hydropower Station， under the flow discharge of 500， 1 200， 2 700， 5 000， 12 000， 13 500 m³/s， the physical model is used to study the navigation condition. The conclusion that the optimization scheme can meet the flow conditions of the entrance area of the approach channel and the navigation requirements of class Ⅲ class waterway is obtained. At the same time， movable bed river physical model is tested to analyze the influence of sediment deposition on navigation conditions of the entrance area of approach channel. It is concluded that the navigation can be guaranteed within 10 years after the station running normally， and giving the measures to reduce the sediment deposition. The research results in this paper can provide the optimal design and demonstration of navigation conditions of hydropower stations， and provide reference for similar projects.

In order to solve the problems of randomness and fuzziness in water quality evaluation， this study uses the game theory to combine analytic hierarchy process， entropy weight method， and coefficient of variation method to obtain combined weights， and couples cloud models to construct a water quality evaluation method. Take Yixing 6 river crossings into Taihu Lake as an example， compare the evaluation results of the newly built method with the single-factor evaluation method and the fuzzy comprehensive evaluation method. The results show that the combination weight of game theory takes into account the advantages of subjective and objective weights. And the results of cloud model water quality evaluation are in line with reality and can better solve the problems of randomness and fuzziness in water quality evaluation. This research can provide a reference for improvement of water quality assessment， water quality evaluation of water bodies and some other studies.

From the perspective of Water-Energy-Food nexus， a multi-objective optimal allocation model of water and soil resources in irrigation areas is established. This model improves the objective functions， constraint conditions and optimization solution method， reflecting the interactive relationships among water resources， energy and food production in irrigation areas. The Water-Energy-Food optimization index and the Water-Energy-Food comprehensive benefit index are constructed to select the optimized schemes and evaluate the corresponding effects. This model is applied to a large irrigation area in China. Eight groups of optimization results and an optimal scheme are obtained. The results show that the optimization effect of the model is obvious. The grain yield， water productivity and energy efficiency of the optimization scheme are 8.31%， 18.93% and 15.49% higher than those of the traditional allocation model， with the net irrigation benefit only reduced by 0.32% but the comprehensive benefit of the irrigation area increased by 11.11%. The model can clearly show the mutual restriction relationship among water saving， energy saving and yield increase in irrigation areas. It can be used for the optimal allocation of water and soil resources in the irrigation area to improve the utilization efficiency of water resources and energy， and the crop yield and irrigation benefits. Therefore， this model provides a new idea for the efficient utilization of water and soil resources in irrigation areas.

In order to study whether the observed and simulated meteorological and hydrological series have obvious similarity and evolution characteristics in history， based on the daily-scale meteorological and hydrological data of Tongcheng hydrological station and meteorological station. linear regression method， sliding 5-year average method， Pettitt test， M-K test and wavelet analysis were used to study the variation trend， abrupt change and period of precipitation and runoff depth series in the upper Junshui River basin. Then， the Xinanjiang model was used to simulate the runoff process， and the similarity between simulated daily runoff and measured rainfall and runoff in different periods was compared， so as to evaluate the reduction degree of hydrological simulation on the evolution characteristics. The results show that the rainfall and runoff in the upper reaches of Junshui River showed an upward trend and several trend fluctuations occurred. In the process of rainfall and runoff evolution， there are three kinds of periodic changes of 12~32， 8~11 and 3~7 years. High accuracy of Tongcheng station was shown. The daily rainfall and runoff series evolution characteristics of Tongcheng station have a good correlation in the 20th century， but have a great difference in the 21st century. And the hydrological simulation accuracy is high， but the characteristics are more similar to rainfall than the observed runoff. Even if evaporation or human activities disturb the hydrological simulation， the hydrological simulation reflects the characteristics of rainfall rather than runoff. Meteorological factors are the main influencing factors of runoff in the upper reaches of Junshui River basin， but the influence of human activities is gradually increasing. Although it is difficult to accurately show the evolution characteristics of runoff， hydrological simulation can still provide basis and support for long-term evolution analysis of water resources， corresponding allocation， flood control and drainage engineering construction in the basin in the future.

In order to study the evolution trend of runoff in the Lancang River Basin under climate changes， the SWAT model of the Lancang River Basin in Yunnan Province is constructed. Different climate change scenarios are set up according to the characteristics of climate change and future trends， and the impact of temperature and precipitation on runoff and evapotranspiration is analyzed. The results show that the SWAT model is highly applicable in the Lancang River Basin. Its simulated runoff correlation coefficient and Nash coefficient calibration and verification results are all more than 0.8. The annual runoff spatial distribution characteristics of the Lancang River present the characteristics of high in downstreams and main streams. Runoff is affected by both temperature and precipitation， and is proportional to precipitation and inversely proportional to temperature. Runoff changes are dominated by precipitation changes. The potential evapotranspiration of the Lancang River is inversely proportional to precipitation and directly proportional to temperature. Potential evapotranspiration is dominated by temperature changes. The upper， middle and lower reaches of the Lancang River in Yunnan Province are selected to analyze the characteristics of climate change， and the Coupled Model Intercomparison Project Phase 6 （CMIP6） and neural network model comprehensive forecast of the climate change trend in the future are compared. After the Mann-Kendall trend test， the temperature in the past forty years mainly has a rising trend. The time and space fluctuations in the precipitation are more complicated， mainly showing a tendency of significant decline， and the variation amplitude between adjacent years is 1 ℃ and 20% respectively.In the future， the temperature will be about 1 ℃/20 a， and the precipitation will be about 10%/20 a rise trend.In the future， temperature and precipitation change will increase the runoff and potential evaporation， and the increase in runoff is concentrated on the rainy season. It can increase by about 38%， and the evaporation is concentrated on the dry season. The maximum increase of about 6%， and the risk of drought and flood in the dry and rainy seasons increases. The strategy of returning farmland to forest in Yunnan Province is more needed to conserve water sources and the dispatch of cascade reservoirs to prevent and control droughts and floods.

The plain basin has a complex hydrological structure， which often leads to floods due to poor drainage. It is very necessary for flood control， disaster reduction and flood management to establish a flood model suitable for the characteristics of plains to simulate the flood process in the plain area. Based on the flood disaster mechanism and the distributed hydrological model MIKE SHE and hydrodynamic model MIKE 11， this paper establishes a MIKE-A-R coupling model to simulate the flood process outside of a river and the hydrological process of the river in the plain area. Taking the upper reaches of Gongjia Sluice of Tuhai River as the study area， the watershed boundary is extracted by using digital elevation and watershed river network data. Based on the data of rainfall， discharge， digital elevation， land use type and soil type， a watershed flood model is established. Through a parameter sensitivity analysis， manning coefficient， riverbed permeability coefficient and other relevant parameters are determined， which are verified by the measured data of Liuqiao Sluice Hydrological Station and field investigation data. The results show that the mike-a-r coupling model can better simulate the flood process outside the river and the river flood routing process in the plain basin. The simulation results can provide a comprehensive data support for flood disaster risk assessment， prediction and early warning.

Poyang Lake is the largest freshwater lake in China and an important wetland in the world. In recent years， drought and flood have occurred frequently， which has attracted extensive attention. Due to its high-frequency fluctuation characteristics， it is necessary to monitor it with long-term high temporal resolution satellites.The variation characteristics of Poyang Lake water area are analyzed by extracting MODIS data from 2001 to 2020， and the response of Poyang Lake water area to meteorological factors is studied by using Mann-Kendall Mutation Test and wavelet analysis. The results show that： ①The seasonal variation of Poyang Lake is significant， and the duration of dry season extended to a certain extent after 2003. The interannual variation trend of the smallest and largest water areas in the study period was weakly opposite. ②The water area decreased after mutation in 2004， and the time series of water area changed regionally over the main period of 18 months（about 1.5 a）， with strong positive and negative alternating law. ③The variation of water area in Poyang Lake responds to meteorological factors， and the meteorological effects are different under different water regimes. Rainfall is the dominant factor affecting water areas.

In order to explore the characteristics of groundwater level change in Huantai County under the changing environment， based on the groundwater level monitoring data from 1982 to 2018 in Huantai County， this paper analyzes the dynamic changes of groundwater level in the temporal and spatial scales， and determines the main factors affecting the changes of groundwater level. By using the trend analysis， M-K test， Pearson correlation analysis and field test， the variation trend of groundwater level and the influence of various influencing factors on groundwater level are analyzed. The results show that the groundwater level has a significant trend of decline in the past 30 years， with a large inter-annual variation， and the average annual difference between the maximum value and minimum value is 6.4 m. During the year， the groundwater level fluctuates in a double peak type， and the variation range is between 0.43~2.78 m. The groundwater depth gradually increases from north to south， and the groundwater funnel is formed in the southeast. The change of groundwater level is mainly affected by precipitation， mining amount and river recharge. Precipitation has a greater impact on groundwater level in northwest， while mining amount has a greater impact on groundwater level in southeast. The main recharge of river to groundwater is lateral infiltration recharge.

The water cycle under changing environment is a hot topic in current water science research. Runoff as an important part of water cycle，identifying the cause for its changes is of great practical importance to water resources management and planning. Taking the Huangshui River as an example， this paper uses the linear tendency estimation， accumulative anomaly， and moving t test to analyze the variation characteristics of runoff. The sensitive method based on Budyko hypothesis is used to evaluate the contribution of climate and human activities to runoff. The results show that annual runoff presented an insignificant decrease trend， and the break points of runoff occurred in 1980， 1990 and 2004. During 1981-1990， precipitation played a vital role in runoff increase. After 1990， underlying surface led to runoff reduction， human activities including construction of hydraulic engineering， conversion of farmland to forest（grassland） and soil and water conservation measures changed underlying surface.

There exist multiple objectives， multiple decision variables and complex multi-constraint conditions in the reservoir water supply dispatching， which presents the characteristics of high dimension， nonlinear and strong constraint. Aiming at the problems of slow convergence rate， low computational efficiency and precocity， a cooperative coevolutionary particle swarm optimization algorithm （CCPSO） based on the population stagnation detection technology was proposed， whitch combines the idea of cooperative coevolution with particle swarm optimization. CCPSO improves the competitiveness of the subpopulation through the competitive evolution among the individuals， improves the global search ability through the cooperation among the subpopulations， and improves the convergence speed through the population stagnation detection technology， and improves population diversity through the evolutionary synergy of various populations. CCPSO is applied to solve Xujiahe reservoir water supply dispatching model， compared with the original particle swarm optimization algorithm， the cumulative total water shortage of domestic， industrial and irrigation calculated by CCPSO is decreased by 47.2%， 33.3% and 14.4%， the probability of water supply is increased by 1.7%， 1.9% and 4.4%， and the water shortage index is decreased by 0.064， 0.071 and 0.076. The results show the application of CCPSO can improve the efficiency of water usage. In terms of algorithm performance， CCPSO can start convergence earlier （about the 65 iterations）， can avoid falling into local optimality， and reduce uncertainty. Therefore， the algorithm is easy to be implemented and the solution efficiency is high， which provides a new idea for the solution of reservoir optimal dispatching model.

Pearson-III distribution （P-III） is widely used in hydrologic frequency analysis.Due to the complexity of calculation， the application of the maximum likelihood method （MLE） to estimate the P-III distribution parameters is greatly limited. Using the logarithmic likelihood function as a fitness function of the particle swarm optimization algorithm （PSO）， solving the numerical solution of the parameter maximum likelihood estimation， PSO-MLE using the optimization algorithm can effectively overcome the defects of traditional computational methods. A modified algorithm of the maximum likelihood is proposed to constrain the mean and position parameters during the optimization of particles for the problem of the likelihood equation. Taking the hydrological frequency analysis of annual rainfall in Weihe Basin as an example， comparing the RMSE， AIC， Filliben correlation coefficient of other parameter estimation methods can show that PSO-MLE method has good practical value and combined with the results of Monte Carlo stochastic simulation analysis， the parameter estimation results of the PSO-MLE method are more unbiased and effective.

By comparing the precipitation measured by ground meteorological stations， multiple indicators are selected from the aspects of capture ability and inversion accuracy， combined with altitude and rain intensity conditions to evaluate the three remote sensing precipitation data sets of CPC， PER-CDR and TRMM on different time scales in the Three-River Source Region. The research results show that： ① CPC products have the strongest ability to detect precipitation （CSI=0.42）， followed by PER-CDR （CSI=0.33）， and TRMM products have the worst ability to detect precipitation （CSI=0.31）. Remote sensing satellite products have a stronger ability to detect precipitation in high-altitude areas （>3 000 m） than in low-altitude areas （<3 000 m）， and their detection performance for light rain is better than moderate rain and heavy rain events. ② On the daily scale， the correlation coefficients of PER-CDR and TRMM are all lower than 0.3， and the highest CPC is 0.47. The correlation coefficients on the monthly and seasonal scales are both around 0.9， and the correlation coefficients on the annual scale are more than 0.8. On the same time scale， the consistency of CPC products and TRMM products is better than that of PER-CDR products. ③ On annual and seasonal scales， TRMM products have the highest accuracy， and monthly and daily scales are the best for CPC products. The RMSE of CPC is smaller than TRMM， which means that the extreme value of CPC error is less than that of TRMM. PER-CDR products obviously overestimate precipitation at all scales， with the lowest accuracy. On different time scales， the daily relative error is the largest， the quarterly and monthly errors are relatively small， and the annual relative error is the smallest. That is， the accuracy of satellite rainfall data improves as the time scale increases. A comprehensive comparison of the three products shows that the CPC product has the best ability to detect precipitation， and has good applicability in the Three River Source Area.

In order to enhance the mixing degree of the two-phase and multi-phase fluids of the jet pump， it is proposed for the first time that a fixed-shaped fin is built in the internal throat of the jet pump. Numerical simulation and orthogonal experiment method is adopted to explore the size of the fin and the fin at different flow ratios. The number of rows， fin spacing and the distance between the first fin and the entrance of the throat pipe affect the mixing effect， efficiency and internal flow field of the jet pump. The results show that the built-in fins can improve the mixing degree of the jet pump as a whole， and the uneven coefficient at the outlet can be reduced from 0.253 4 to 0.074 3 at the highest. The change of the flow ratio can easily lead to changes in the influence trend of the fin parameters on the mixing effect. Efficiency is available in the meanwhile. There are some models that improve the mixing degree of two-phase fluids without reducing the efficiency. Based on the analysis results， the optimal configuration of each parameter is predicted. It has certain reference value to analyze the internal flow field and optimize the structure of the jet pump to improve the mixing effect.

In this paper， the finite element model （FEM） of large-diameter buried Q235C continuous pipeline crossing fault is constructed by the finite element software ABAQUS. The optimal crossing angle under normal fault， reverse fault and strike-slip fault is investigated based on the strain failure criteria. What′s more， the influence of the crossing angle on the maximum axial strain and the failure length of the buried pipeline is also studied. The results indicate that normal fault displacement will cause large axial tensile strain in the pipeline and the crossing angle has negligible effect on the maximum axial tensile strain of the pipeline， while pipeline passing through reverse fault is mainly subjected to compression and the crossing angle has a significant influence on the maximum axial compressive strain of the pipeline. As for the pipeline crossing strike-slip fault， pipelines are prone to failure due to tension when the crossing angle is less than 90 degrees and pipelines are subjected to comparatively larger compressive stress when the crossing angle is greater than 90 degrees. The influences of crossing angle on the maximum axial strain and the failure length of the buried pipeline under different buried depths are similar. The crossing angle between the pipeline and the fault is recommended to be 75 degrees to 105 degrees under the normal and reverse faults and 75 degrees to 90 degrees under the strike-slip fault.

Drinking water sources have a relatively high strategic position. After years of water source protection and governance， China’s water volume has basically met the demand for water supply. Under the new situation， a new concept of drinking water source safety and new evaluation method system are proposed. The four aspects of water volume， water quality， water quality risk and management problems faced by lake-reservoir-type drinking water sources are summarized， the research results in the field of safety evaluation of lake-reservoir-type drinking water sources at home and abroad are combed， then the concept of drinking water source safety is given， and analytic hierarchy process is used to construct four evaluation index systems of water safety status； water quality risk prevention and control and standardization of water source management are proposed， and a lake-reservoir-type water source safety evaluation method is proposed tentatively， which is helpful to regularly evaluate water sources， find and solve problems in time， so as to better protect drinking water sources. The method is used to evaluate the drinking water source of Gangnan Huangbizhuang， the results show that the drinking water source of Gangnan Huangbizhuang is in good safety condition.

A water hammer protection scheme that combines multiple surge towers for super-long gravitational water conveyance system is proposed. The surge towers are a new specific overflow type that closes flow in its bottom and connects flow in its top， which can suppress water hammer pressure and divide the long system to several sections for preventing the spread of pipe burst accidents. The design principle of the scheme is given， in which the key is to determine the crest elevations of the downstream overflow weir and outer overflow weir of the surge tower. A surge tower should be set at the end of the pipeline， and there should be a reservoir nearby to discharge the overflow water； the crest elevations of the outer overflow weirs of this tower is the controlling parameter of the hydraulic gradeline of the system； several towers in the middle of the system should be set according to landform conditions； the crest elevations of the downstream overflow weirs of these towers in the system middle are determined to ensure adequate flow capacity； the crest elevations of the outer overflow weirs of these towers are selected to prevent or reduce overflows out of the system in transient conditions. The analysis combined with an engineering example shows that the scheme can significantly decrease water hammer pressure along the system and is an appropriate candidate for similar projects.

In order to accelerate the dissipation of pore water pressure in the core wall， the width of the core wall was reduced during the construction of the Hyttejuvet dam in Norway， resulting in a structural variation of the core wall and the occurrence of hydraulic splitting after initial water storage. To investigate the effect of this structural variation on the formation of hydraulic splitting， centrifugal model tests were used to simulate the stress state of the abruptly altered section of the core wall during the construction and storage periods， and to successfully reproduce the hydraulic splitting phenomenon at the abruptly altered core wall slope ratio. The test results show that due to the mechanical properties of the fill material and the development of consolidation， an arch effect is formed near the contact surface between the core wall and the dam shell， and the water pressure is laterally loaded during the initial storage period， resulting in a local stress deflection phenomenon where the vertical stress is less than the horizontal stress. Based on the Geostudio seepage-stress coupling module， an earth and rock dam model was developed to analyse the location of the risk of hydraulic splitting at the upstream face of different forms of the core wall. Numerical simulations show that the arch effect is most pronounced in the core wall of the mutated section， while the arch effect is significant above an elevation of 85 m. The smaller the slope ratio， the weaker the resistance to hydraulic splitting damage.

To reveal the influence degree of the water conservancy project construction on water environment， this paper improves water conservancy project construction project investment decision-making， considers the natural conditions and social economic impact on the water environmental benefits on the basis of 10 water environmental benefits related indexes. Based on two-level fuzzy comprehensive evaluation method， China’s water supply project in Gansu Province comprehensive evaluation is constructed. The entropy method is used to determine the index weight， and three-criterion layer weight distribution schemes are designed by considering the importance of ecological environment and engineering benefit. The fuzzy calculation results show that the water environmental benefit level of tao water supply project is good and its benefit is significant. The benefits are particularly significant in terms of water supply and population health. The above results objectively reflect the water environmental benefits of Yintao Water Supply Project， and verify the validity of the research method and the rationality of the evaluation model， which can be used for reference in engineering practice.

Geotube is a heterogeneous structure composed of fillings sand and bag materials， and its permeability is affected by filling sand and geotextile. To explore the permeability characteristics of sand covered with geotextile， the permeability tests of filling sand with different particle grading under the condition of sand covered with or without geotextile are carried out. The influence of particle grading on permeability coefficient of filling sand and sand covered with geotextile are explored. And the influence of geotextile on permeability coefficient is analyzed by comparing permeability coefficient of sand covered with and without geotextile. The test results show that the influence of single particle size content is linearly related to their respective permeability coefficients under the condition of sand covered with or without geotextile. But under the same grading conditions， the permeability coefficient of sand covered with geotextile is smaller than that of pure sand. Finally， the empirical formula of permeability coefficient of filling sand and sand covered with geotextile are fitted with a new parameter d_{\mathrm{50}}^{\mathrm{2}} ( C_c / C_u ).

In the engineering of rock breaking by the impact hammer or blasting， in order to optimize the design and construction scheme， it is often necessary to grasp the mechanical characteristics of rocks under dynamic loads. RHT model can be used to simulate the damage characteristics of brittle materials such as granite. The accurate determination of the granite RHT model parameter requires many numerical simulations on the basis of dynamic tests under different strain rates， and then the parameters of RHT model are optimized. The numerical simulation process is complicated and the efficiency is very low， which brings great inconvenience to engineering personnel to determine the parameters of RHT model. In this paper， a method for determining parameters of granite RHT model based on MATLAB is proposed. The input file， execution file and result file of LS-DYNA software are modified and processed by MATLAB software， and then the joint numerical simulation of MATLAB software and LS-DYNA software is realized. The parameters of granite RHT model in Shenzhen Zhongshan Tunnel are optimized. The method can provide an effective way to determine the parameters of RHT model in practical projects.

There have high proportion of abnormal errors in the monitoring data of hydropower units， to improve the data quality， this paper studies the identification of wrong data and the recovery of missing data. Aiming at the problem of error data identification， combined with the characteristics of delay and similarity in the data， the K-means clustering method is used to identify abnormal data； For problems such as missing data， according to the characteristics of small samples and nonlinearity in the data， the support vector regression is used to recover the missing data； A data processing method for error identification and loss recovery based on the K-means clustering and support vector regression is constructed. Finally， the effectiveness of this method is verified by using the actual monitoring parameters.

Numerical simulation is an indispensable method for the investigation of aerated flow. However， limited by the cognition of microcosmic air-water coupling mechanism and multiphase flow simulation techniques， the application of mathematical models that are able to include the aeration effect remains rare in the field of water conservancy and hydropower engineering. In order to explore the accuracy of the sub-grid air entrainment model in FLOW-3D， the air-water two-phase flow on a stepped spillway is simulated as a benchmark. The simulation results are compared with the experimental data. It is found that the air entrainment model in FLOW-3D is able to correctly reproduce the turbulence development in the non-aerated region and the inception location of the surface air entrainment. Moreover， the computed bubble diameter is reasonable. However， the model still has to be improved since the calculated velocity and air concentration profiles remain unsatisfactory. The drag coefficient and Richardson-Zaki coefficient multiplier have an insignificant effect on the air concentration results. Affected by the FAVOR technique， the turbulence parameters are very sensitive to grid resolution. Based on the above results， the reliability of the sub-grid air entrainment model is comprehensively evaluated， and thus several suggestions are put forward for its future improvement. This paper can be used as a reference for the development of related numerical models and simulations of similar engineering problems.

The basic principles and degradation function of phase field method for quasi-brittle fracture are introduced in details. A novel degradation function is proposed， in which the power degradation function and Borden degradation function are coupled by a weight coefficient. The novel degradation function can reflect the fracture behavior of materials comprehensively. A 2D program for the phase field method is implemented. It is confirmed that the program is accurate by using a single-edge-notched square plate subjected to tension. The impact of the novel degradation function on the fracture behavior of single-edge-notched square plate is studied. If the parameter s and m increase， the load peak will decrease. With the increase of parameter， the load peak will increase. Meanwhile， the fracture of notched semi-circular bend （NSCB） rock specimen is modeled， and the effect of the novel degradation function on the fracture propagation of NSCB is analyzed. The parameter m has a less effect on the load peak. The load peak is negatively correlated with parameter s and positively correlated with parameter w. The novel degradation function can reflect the behavior of quasi-brittle fracture and brittle fracture.

Based on the DFID sustainable livelihood analysis framework， this paper discusses the action mechanism and boundary conditions of the relationship between the implementation effect of later supporting policies for relocation and the resettlement of hydropower projects and the sustainable livelihood outcomes. Through the household survey of immigrants in the relocation reservoir area of hydropower projects in the old revolutionary base area of Zuoyoujiang River， 377 valid questionnaires are obtained， and SPSS is used for regression analysis. The results show that there is a significant positive correlation between the implementation effect of later supporting policies and the sustainable livelihood outcome of relocated immigrants of hydropower projects， the livelihood capital risk plays a partial intermediary role in the relationship between the implementation effect of later supporting policies and the sustainable livelihood outcome， and the risk response strategy regulates the intermediary model.

The rotary flow shaft spillways are widely used in many projects because of their many advantages. In order to provide more references for the design， operation and protecting of this kind of spillways， the hydraulic characteristics of the shaft spillways are needed to be investigated further more. Mainly based on the physical model experiment， the amplitude of the flow pulsating pressures and its frequency spectrum characteristics in the vortex chamber of the vertical shaft spillways with different baffle angles are studied. The experimental and the analytic results show that the flow fluctuating pressure intensity in the vortex chamber increases with the increase in the baffle angle， and the fluctuating pressure intensity is closely related to flow energy dissipation. The probability density of the flow fluctuating pressure conforms basically to normal distribution， but it is not the standard normal distribution. The relationship of the skewness coefficient to the baffle angle is weak. The kurtosis coefficient decreases with the increase in the baffle angle， but the range of the amplitude for the kurtosis coefficient increases. With the increase in the baffle angle， the dominant frequency range of the fluctuating pressure widens and gradually shifts to high frequency. The pulse energy of flow is mainly determined by the large-scale vortex with high frequency.

Water balance is the most basic principle in the field of hydrology and water resources. By studying regional water balance， this paper can determine the relationship between regional hydrological elements， reasonably understand and evaluate regional water resources， and guide the optimal allocation of water resources. Based on the principle of water balance， the balance difference and interval runoff coefficient are used to calculate and analyze each hydropower station and hydropower station interval on Yujiang River basin， and it is found that there is an obvious water imbalance phenomenon in actual operation. The existence of this phenomenon has caused a series of impacts on flood control， incoming water prediction and forecast， and joint optimal operation scheme， and affects the economic benefits and safety production of the stations. By analyzing the elements of water balance and its calculation process， the main reason for water imbalance is that the reservoir characteristic curve of the hydropower station has changed over the years of operation.

The uncertainty of geotechnical parameters and the changes of the external environment have a direct impact on the stability of the slope. Therefore， the reliability analysis of the reservoir bank slope is of guiding significance for the safety assessment. First， appropriate levels for uncertain influencing factors are selected and the uniform experimental design method is used to determine the samples required by the neural network. Then， according to the slope parameter distribution range， the limit equilibrium method and LHS are used to solve the corresponding samples. Finally， the RBF neural network optimized by PSO is used to train and test sample and its stability factor， failure probability and reliability index so as to establish the slope reliability prediction model of the homogeneous reservoir bank and compare it with the prediction results of the RBF network. The analysis results show that the PSO-RBF is established on the basis of uniform experiments and have good prediction accuracy， and is further than the RBF， and it can also save time. The research results have certain reference value for the early warning of the stability of the reservoir bank slope engineering and disaster prevention.

It is very important to analyze the matching degree of the groundwater and crop layout in irrigated areas for the sustainable utilization of groundwater resources and high-quality development of irrigated areas in the Yellow River Basin. Innovation trend analysis（ITA） and Mann-Kendall method are used to analyze the dynamic characteristics of groundwater depth in irrigated areas. Based on the data of land use and land cover （LULC） and groundwater depth， the spatial autocorrelation between the groundwater depth and the crop layout and the matching characteristics of spatial pattern are quantitatively discussed by using Moran?s I analysis method. Spatial mismatch index is used to analyze the spatial mismatch between the groundwater depth and the crop layout in the current year （2018）. The results show that： ①The groundwater depth in the irrigated area increases with time. ②The global analysis results show that there is a positive spatial correlation between groundwater depth and crop layout. Local indicators of spatial association（LISA） analysis shows that the changes of high-high aggregation and high-low aggregation are the most significant. ③The annual groundwater depth and crop layout in irrigated areas are seriously mismatched. Therefore， it is necessary to make reasonable use of well irrigation and canal irrigation in combination with the matching relationship to reduce the grade of spatial mismatch index.

In order to explore the influence of the residual film on soil moisture content and tomato photosynthetic characteristics and provide a basis for establishing a tomato photosynthetic model in soil with the residual film. The study sets up 5 residual membrane levels of 0 kg/hm² （T1）， 200 kg/hm² （T2）， 400 kg/hm² （T3）， 800 kg/hm² （T4）， 1 600 kg/hm² （T5） to conduct field trials and determine the differences at the level of residual film， tomato leaves photosynthetic rate， stomatal conductance， SPAD， water content and other parameters， the measured data are processed by correlation analysis and path analysis and a correlation regression model is established. The results show that on a time scale， the ground temperature changes in an S-shaped curve， and the ground temperature increases with the increasing amounts of the residual film. The maximum photosynthetic rate in each growth period occurs when the amount of the residual film is 800 kg/hm²； the stomatal conductance of leaves during the complete growth period shows a downward trend， with 200 kg/hm² in the same growth period. The stomatal conductance of the treatment is significantly higher than that of the other treatments； the SPAD of the leaves decreases first， then increases， and reaches the peak during the fruit swelling stage. Leaf photosynthetic rate is significantly correlated with stomatal conductance， SPAD， relative humidity， ground temperature， and average moisture content， and the amount of the residual film is significantly correlated with average moisture content. Through path analysis， the direct leading factors affecting leaf photosynthesis rate， from large to small， are stomatal conductance （0.671）， ground temperature （0.198）， and average water content （0.169）. Residual film mainly depends on changing the soil moisture content and ground temperature to indirectly affect the photosynthetic rate. The research results help to further analyze the influence of indirect factors on leaf photosynthesis rate under the condition of soil containing residual film， and provide a reference for a comprehensive understanding of the effect of residual film on crop growth.

There are a large number of farmland drainage ditches with wide distribution， which have dual functions of excluding farmland surface water and reducing groundwater. Because of the need of slope stability and the depth of waterlogging， the width of farmland soil drainage ditch is generally more than 2 m， occupying more arable land， and the investment of crossing ditch buildings is also large. It is particularly important for well-facilitated farmland construction to seek a stable， ecological and permeable farmland drainage ditch masonry structure which is land-saving and investment-saving. On the basis of ensuring the permeability and ecology of the drainage ditch， this paper puts forward a new design scheme of the mesh ecological drainage ditch with the slope stability as the premise and the minimum width of the mouth and the minimum amount of concrete as the goal. A stability analysis of the ditch under different soil conditions show that the ditch has good stability， characteristics such as land saving， a low investment， convenient construction， permeability and ecology， which serve as an effective channel management method for well-facilitated farmland construction and ecological farmland construction.