Because the terrain of long-distance and complex water conveyance projects is generally complex， the hybrid water conveyance mode combining pump pressurization and pressurized gravity is becoming increasingly common in engineering practice. Limited by objective conditions such as terrain， it is difficult to improve the water hammer control effect of long-distance and complex water transmission pipeline only through single valve regulation， so it is difficult to ensure the safe operation of the whole project. Therefore， it is of great practical significance to study and solve the joint optimal operation of pumps and valves in the mixed water conveyance system. In this paper， taking the gravity pressurized water conveyance project from Gaotuan Pump Station to non- pressure regulating tank as the research object， the transient flow simulation model from Gaotuan Pump Station to non-pressure regulating tank is established， and the operation state before and after switching is simulated， and the boundary conditions are defined. Based on the analysis of the current regulation scheme， taking the time interval of pump valve joint regulation as the control variable， the transient process of various switching schemes is simulated and analyzed， and the existing pump valve joint regulation mode is optimized. An operating scheme of pump valve operation with short regulation time， simple operation， small water level fluctuation and high safety is proposed， which provides data support for the joint optimal operating of pump valve in long-distance complex water conveyance projects.

In order to study the influence of the inhomogeneous inlet flow field generated by different inlet structures on the hydraulic performance of the axial-flow pump， this paper is based on the Reynolds time-averaged N-S equation and the standard k-ε turbulence model， and the numerical simulation calculation of the vertical axial flow pump device is carried out by using CFD software. The inlet flow path is simplified to a 90° inlet elbow， the non-uniform inflow caused by the elbow structure is compared with different curvature radii and the uniform inflow of straight pipes， and establish two typical non-uniform inflows and uniform inflow of straight pipes on the basis for comparison， the influence of the inlet non-uniform flow field on the hydraulic performance of the axial flow pump is obtained. Comparing the numerical simulation results of straight pipes with uniform inflow with the model test verifies the reliability of the calculation results. The results show that the smaller the radius of curvature of the elbow， the higher the degree of non-uniformity of the pump inlet flow field， and the greater the impact on the lift and efficiency of the vertical axial flow pump， and this impact is more obvious in large flow conditions. The maximum difference in efficiency between the inlet distortion flow fields produced by different elbow structures reaches 11%， and the maximum difference in head reaches 0.41 m. The hydraulic loss of the guide vane and the outlet channel under the condition of non-uniform inlet flow increases significantly， and as the radius of curvature decreases， a vortex will be generated on the side of the guide vane， which weakens the recovery and rectification of the guide vane. The comparison between two typical non-uniform inflow and uniform flow shows that the non-uniform flow may enhance the functional power of the impeller， which greatly increases the head of the vertical axial flow pump， but greatly reduces the efficiency of the impeller. The research can provide a reference for the optimal design of pumps under the condition of non-uniform inlet flow.

Affected by the change of water level in the Changjiang River， the bidirectional channel pumping station is easy to deviate from the design condition， causing bad pressure fluctuation and affecting the safe operation of pumping stations. The unsteady calculation based on RANs equation and SST k-ω turbulence model is used on abidirectional channel pumping station model for obtaining the pressure fluctuation time series under the design conditions. The results are verified by external characteristic tests. In order to study the chaotic characteristics of pressure fluctuation in bidirectional channel pumping station， the phase space reconstruction of time series is carried out， and the maximum Lyapunov exponent， correlation dimension and fractal scale are calculated and analyzed. The study shows that the maximum Lyapunov exponent of each monitoring point is more than 0， indicating that the time series have chaotic characteristics. P₉ at the impeller outlet has the largest correlation dimension， and point 18 at the outlet horn outlet has the smallest， which is corresponding to the of pressure fluctuation amplitude. The fractal scales are all more than 0， and the fractal scale value at P₁₅ in the middle of the guide vane is the largest， indicating that the chaotic characteristics are the strongest in this case.

With the continuous development of water diversion project information construction， the importance of water conservancy project operation and maintenance system is gradually increasing， and the traditional operation and maintenance system is not enough to support today’s demand. It is urgent to establish an intelligent operation and maintenance system that meets the actual needs of water conservancy project information system operation and maintenance management. Based on the operation and maintenance needs and characteristics of water diversion and water conservancy projects， this paper systematically expounds the main points of operation and maintenance of water conservancy projects， studies the key technologies of operation and maintenance by means of the integration of intelligent and information technologies such as cloud computing， big data and artificial intelligence with Internet technology， and completes the overall framework design and functional module design of the system through demand analysis. Finally， a set of intelligent operation and maintenance management system of water diversion and supply project based on “cloud network end” architecture will be formed. The system can comprehensively improve the safety and reliability of water conservancy project system operation， and provide technical support and reference for similar water conservancy project intelligent operation and maintenance management.

This paper studies the integrated platform of intelligent management in pump station which is unified construct the developing of big pump stations units safety， operation， dispatching， analysis and decision-making of， and to realize the function of monitoring and diagnosing the station of pump station units operation， analyzing the economizing operation of pump station， complement decision on optimal operation and omnibearing displaying the information of pump station. Which was applied in the upgrading and reconstruction project on Denglou pump station automation system in Shandong section of 1st pha of the south-to-north water diversion project， The project deeply analyzes all kinds of information about pump station by using big data， internet of things，cloud computing to realize omnibearing data perception， full-automatic safety control， all scene intelligent prewarning and omnibearing safety prewarning and prediction， Achieve the goal of “remote automation control， business management informatization and intelligent dispatching decision-making”， and realize the visualization of dispatching production indicators， management intensive of operation state， intelligent of operation dispatching and intelligent management of pump station.

In order to solve the frost heaving and thawing settlement of channel foundation soil in deep excavation high groundwater level in GuhaiYanghuang irrigation area， resulting in uplift and collapse of concrete slab. Based on the actual situation of the damage of channel concrete lining slab， this paper analyzes that the main reason for the damage of channel concrete lining slab is that the water content of channel foundation soil is too large， resulting in the frost heaving damage of concrete slab； Reducing and eliminating the water content in the foundation soil is the main measure to solve and prevent the frost heaving damage of the channel. In this paper， the combination of capillary permeable drainage belt and drainage pipe is used to remove the groundwater in the foundation soil， reduce the water content in the canal embankment soil， and solve the problem of frost heaving damage of canal concrete slab. The results show that compared with the maximum water content of foundation soil in the channel section without drainage measures， the maximum water content in the initial stage of freezing， freezing period and after melting in spring is reduced by 21.4%， 14.7% and 27.9% respectively； The maximum normal frost heaving on the sunny slope， the shady slope and the bottom of the canal is reduced by 74%， 79% and 50% respectively. It shows that the combination of capillary permeable drainage belt and concealed drainage pipe can effectively reduce and prevent the occurrence of frost heaving damage of the channel.

In high water table canal sections， the side slopes of open channels are prone to lift pressure damage， resulting in serious accidents such as lining slab damage， landslides and even water stoppages. To reduce the groundwater level， this paper proposes the use of a composite drainage method combining longitudinal drainage pipes and in-channel pressure-reducing wells in areas with high groundwater levels. Under conventional conditions， the longitudinal drainage pipe is simply used for drainage， while in the case of high water table， the pressure-reducing well is activated so that the pipe and well operate simultaneously to rapidly reduce the groundwater level and avoid causing damage to the lifting pressure. A three-dimensional finite element model is constructed to solve the problem of simultaneous simulation of drainage pipes and drainage wells in a two-dimensional model for the lifting pressure damage problem in the Piaobu Section of the Jiaodong Diversion Project in Shandong Province. The numerical calculation method is used to compare the pressure reduction effect of drainage in three modes， namely， using only longitudinal drainage pipes， using only pressure-reducing wells and combining pipes and wells， and studying the pressure reduction effect of the location of pressure-reducing wells， the spacing of wells and the pumping elevation in wells on the bottom and slope of the canal. The results show that the drainage pressure reduction requirements can be met under conventional conditions by simply using drainage concealed pipes， but not under high groundwater table conditions. The composite drainage method of combining pipes and wells can meet the drainage pressure reduction requirements and provide theoretical support for the design and operation of high water table canal sections in long-distance water transmission open channels.

The design of the side channel should ensure that the side weir is free outflow， which means that the water depth of the channel head section needs to be calculated according to the check flow. The effect of the change of bottom slope of the side channel on the submerge of the channel head is studied by numerical simulation. The results show that：① under different bottom conditions， the increase in the flow capacity of the side weir increased first and then decreased；② the submerge of the side weir can be avoided by increasing the length of the side weir （the difference in height between the head and the end of the channel remains unchanged） and decreasing the bottom slope of the side channel within the range of the studied longitudinal slope changes. When it is difficult to reduce the height difference of the bottom plate at the beginning of the weir due to geological conditions， the length of the side weir arranged along the contour can be increased to ensure that it will not be submerged when it overflows， and the super discharge capacity of the side channel spillway can be appropriately improved.

The seismic performance of the upper pool structure of the high-fill site in the earthquake area has an important impact on its safety and stability during the operation period. Based on a pool structure construction project in southwest China， an indoor shaking table scale model test is designed， and a three-dimensional numerical model corresponding to the test is established to verify the rationality of the test scheme. The dynamic response of the soil under different conditions， the displacement and stress response of the upper pool structure are mainly studied， and the effect of different foundation treatment methods on controlling the excessive displacement of the pool structure is further analyzed. The results show that the acceleration response of the hard rock layer is gradually significant with the increase in elevation， and the seismic wave energy and amplitude near the surface are attenuated due to the filtering effect of the fill layer； the vertical displacement of the pool structure is positively correlated with the intensity of ground motion and the storage of the water， the middle wall of the pool near the intersection of excavation and filling is subjected to the maximum principal stress； adding pile foundations and improving the filling properties are effective for controlling excessive displacement of the pool structure method. The results of numerical analysis show that the experimental design scheme is feasible and can provide a reference for the design optimization and improvement of the shaking table test.

In order to explore the suitable comprehensive water-fertilizer regulation mode and its water-saving and emission reduction effect in garlic field in Erhai Basin， an experiment of garlic water and fertilizer regulation mode is carried out in Dali Observation and Experimental Station of National Agricultural Environment. Two irrigation levels are set up： conventional irrigation （W0） and water-saving irrigation （W1）； Conventional fertilization （N0）， 15% reduction of nitrogen fertilizer （N1） and 30% reduction of nitrogen fertilizer （N2）， a total of 6 treatments. The results show that compared with W0， W1 treatment saved 31.09% of irrigation water， 51.15% of total nitrogen loss and 44.25% of total phosphorus loss decreases， and crop water use efficiency increases by 3.07%. Under the same irrigation mode， the garlic yield of N1 treatment decreases by 4.31% compared with N0 treatment， the difference is not significant， the total nitrogen loss decreases by 35.73%， the total phosphorus loss decreases by 2.68%， and the crop water use efficiency decreases by 3.23%. Under N2 treatment， garlic yield decreases significantly by 30.59%， total nitrogen loss by 42.89%， total phosphorus loss by 2.71% and crop water use efficiency by 28.93%. In the total nitrogen and total phosphorus loss， the loss through surface runoff accounts for 6.68% and 12.51% respectively， and the leaching loss accounts for 93.32% and 87.49% respectively， that is， the leaching loss is the main loss of total nitrogen and total phosphorus. Considering the effects of water saving， yield and emission reduction， N1 nitrogen application rate and the water-saving irrigation mode with 70% of field water holding rate as the lower irrigation limit and the upper irrigation limit as field water holding rate is the better water-fertilizer management mode in this area.

By comparing and analyzing the essential difference between traditional Value Engineering （VE） and engineering construction scheme comparison and selection， a quantitative model more in line with the requirements of project scheme selection is proposed based on the concept of VE. And it is applied to the selection of membrane technology in water supply plants. It is calculated that the value coefficient of the scheme with treated water volume of 60 000 m3/d is 0.475， which is the best scheme. This conclusion is basically consistent with the results of conventional qualitative analysis. The results show that the proposed model can better conform to the actual engineering， and the obtained results are more scientific and reasonable. It is a strict logical and universal method， which can better adapt to the actual needs of the engineering plan and is worthy wide spreading.

To understand the state of a diversion tunnel surrounding rock under the action of water deterioration creep deformation law of selection after immersed tunnel rock as the research object， to carry out the different moisture contents under the action of uniaxial loading creep test， the effects of moisture content of tunnel surrounding rock creep， this paper establishes a double influence of moisture content and time unsteady creep model of new type. Finally， the correctness and rationality of the model are verified with experimental data. The results show that the instantaneous deformation and creep deformation of sandstone under load increase gradually with the increase in water contents， and the unsteadily established model takes into account water content deterioration and time deterioration of creep parameters， so the creep model can accurately describe the creep damage process of tunnel surrounding rock under different stresses and different water content states. And parameter α ₁ can effectively control the instantaneous strain value of rocks， the size of the parameter α ₂ is a viscoelastic deformation for rock and the rate of variables， parameter α ₄ controls the sticky plastic creep rate and parameter α_γ in plastic sticky glue pot works， to stick to plastic deformation of viscoelastic deformation rate， effectively maintaining the accuracy of the model curve.

Terrestrial water storage in the source region of the Yellow River plays an important role in the ecological protection and high-quality development of the Yellow River Basin， which is a part of the implementation of the national major strategy. Based on GRACE and GRACE-FO gravity satellite products and GLDAS product， this paper utilizes long short-term memory （LSTM） network model and analyzes the variation characteristics of terrestrial water storage in the source region of the Yellow River from April 2002 to March 2020， and investigates the influences of precipitation and evapotranspiration on the changes in terrestrial water storage. Results indicate that the LSTM model can be used to reconstruct the data gap between GRACE and GRACE-FO products with Pearson correlation coefficient of 0.923 and Nash efficiency coefficient of 0.816 at the test period. In addition， the terrestrial water storage data from GRACE has a good reliability， and against GLDAS data with the Pearson correlation coefficient of 0.73. The terrestrial water storage has a variation trend of first increasing， then decreasing and then increasing， and an apparently increasing trend in the source region of the Yellow River integrally. Compared with groundwater and snow water equivalent， the increase in soil moisture makes the major contribution to the increase in terrestrial water storage. The precipitation increasing is the significant reason for the increase in terrestrial water storage in the source region of the Yellow River， and the evapotranspiration decreasing is the possible reason.

An additional solid-state carbon sources should be added to the medium soil for denitrification requirements， when engineering graded medium soil is used as the filler in the bio-retention system. This manuscript focuses on the treatment of balcony laundry wastewater and runoff by bioretention system， exploring different cellulose solid-state carbon sources （sawdust， coconut husk， corn residue， rice husk， wheat straw）， and addition amounts （0%， 3%， 5%， 7%， respectively， wt.%） on the decontamination performance of the system. The results show that all the carbon source materials could release a large amount of organic carbon， which is needed in the denitrification process. Among them， the sawdust additive group exhibits the strongest denitrification ability， with a removal efficiency of 95%. In the rainwater-greywater dual mode， the addition of carbon sources can improve the capacity of nitrogen removal efficiently， especially for the NO₃ ^--N removal. In addition， external added carbon sources can significantly improve the removal efficiency of phosphorus in the bioretention system. However， excessive carbon source will cause the increase in effluent NH₄ ⁺-N. The addition of carbon source can cause the increase in the effluent COD concentration. Considering the pollutant control target comprehensively， adding 3% sawdust to the medium soil in the submerged area can meet the carbon source demand of the rainwater-greywater dual-mode bioretention system for the treatment of the laundry wastewater from the balcony and the rainfall runoff of the old community.

Under the new situation， the new idea of water management requires the reflection of human-water harmony concept in the planning and design of revetment projects， which can help yield the greatest comprehensive benefits of flood control， ecology and economy. River hydraulic calculation is the key link between watershed hydrological analysis and hydraulic structure design， and has a significant impact on the selection of revetment type， project scale and cost. Taking the typical small and medium mountain rivers， namely the Nanchuan River in Liuyang City as the study area， this paper uses the MIKE11 one-dimensional hydrodynamic model for hydraulic calculation based on the designed basin flood inputs， and puts forward differentiated ecological revetment project schemes aiming to solve different problems， and then analyzes the effects of revetment projects. The results show that the MIKE11 model after parameter calibration can accurately simulate the flow regimes of the Nanchuan River， and the calculation results can help to guide the selection of revetment type and determination of the related design parameters. The ecological revetment project schemes formulated based on the model results can help to consolidate the bank slopes， promote the flood propagation， stabilize the river regimes and improve the channel ecological conditions.

Rapid urbanization and climate change lead to frequent floods. Optimization of urban drainage system design is of great significance to urban drainage and waterlogging prevention. A practical case in Xiaozhai of Xi′an is taken as an example， the study selects two types of drainage infrastructures， i.e. drainage pipe network and storage tank， combines the SWMM model with the NSGA-III algorithm through the program， and proposes a multi-objective optimization method for the design of grey drainage infrastructures with the objectives of minimum nodes overflow， economic investment and maximum runoff control rate. The results show that compared with the original planning scheme， the method proposed in this paper is superior in terms of three objectives. The total overflow of the pipe network nodes has decreased by 11.70%， the economic cost has decreased by 4.55%， and the total runoff control rate has increased by 4.06% at the 50 a design rainfall. In addition， the three objectives have shown different degrees of improvement in the design return period of 10a and 20 a. The research results can provide a theoretical basis and technical support for the design of urban grey drainage infrastructure.

With the economic development and the increase in foreign population in Shenzhen， it is urgent to develop the west coast and build a new industrial base to solve the problem of land shortage. It plans to reclaim the shoal water area and mariculture area on the left bank of Maozhou Estuary. The reclamation boundary line is beyond the existing shoreline and the nearshore trough will be landfilled. Therefore， it is necessary to study the impact of reclamation project on water flow diffusion characteristics and riverbed stability and the evolution in Maozhou Estuary after the project construction which made the -3 m contour line cut off. The model is verified by using the measured hydrological data to ensure that the model meets the similarity requirements of flow and sediment movement. Based on an analysis of bed sediment characteristics， the plastic sand with specific gravity of 1.22 t/m³， median particle size of 0.23 mm and starting velocity of 4.3~5.2 cm/s are selected as the bed sand for the model test. The physical model test of the movable bed is carried out to simulate the hydrodynamic and river bed evolution. The test results show that after the implementation of the reclamation project， the coastal sediment transport path is blocked with the nearshore deep trough disappearing， the mainstream is compressed westward， the sediment is transported and diffused on the west shoal of the project and finally under the combined action of Maozhou River runoff and rising tide， a new deep trough is formed on the shoal. The new deep trough， which is basically continuous， extends from Maozhou Estuary to the southwest close to the shoreline， but the -3m contour line is not connected and the widening rate is small. Compared with the current situation， the deep trough distribution characteristic is similar， but the width of the new deep groove is narrow and the depth is shallow. According to the test results of riverbed evolution autogeneity， the rising and falling tide， which washes and erodes the riverbed from the upstream and downstream directions respectively， has strong bed-building capacity in nearshore water areas. On the basis of riverbed autogenic test， combined with the flow and riverbed evolution characteristics and the new deep trough distribution characteristics， the Maozhou Estuary regulation scheme is put forward.With a total length of about 4.0 km， the regulation scheme， which is connected with the upstream deep groove of Maozhou Estuary as the starting point and -4 m contour line of the east shoal as the downstream， is recommended to excavate the deep trough to -4.0 m， which is basically arranged along the new scouring deep groove in the research results. The excavation scheme of the new trough is 150 m wide at the upstream bottom， 200 m wide at the downstream bottom and the slope is 1∶7.

To improve the mechanical properties and the resources utilization of dredged sediment in the Bahe River. On the basis of traditional Portland cement curing， lime， polypropylene， slag and polymer absorbent resin are added to make composite curing agent. The influence of different dosage of curing materials on the strength of dredged sediment with high water content at different ages is analyzed through unconfined compressive strength test， and the correlation between the dosage of curing materials and the strength of dredged sediment is analyzed. The results show that the content of slag and quicklime has a significant effect on the strength of dredged sediments. The cement content has a relatively significant effect on the strength of dredged sediments. The content of polypropylene and polymer absorbent resin has little effect on the strength of dredged sediment. The optimum mix proportion of composite curing agent is： Cement（A）∶ quicklime（B）∶ polypropylene（C）∶ slag（D）∶ polymer water absorbent resin （E） = 2 000∶400∶10∶1 100∶8. After that， the regression prediction model of dredged sediment strength with different dosage of curing agent is established based on the stepwise multiple regression method. The research results may provide a basis for the recycling of dredged sediment produced by the ecological environment treatment of the Bahe River in Xi′an.

MIKE21 software is used to establish a two-dimensional hydrodynamic model of Lancun to Fenhe second dam， which considers the collapse process of the rubber dam and the interval confluence. Firstly， the parameters are calibrated according to the physical model test results and the constant flow surface line simulation. Through the simulation of the measured flood process and the rubber dam collapse process， the established model is verified. The water level and flow are in good agreement， and the established model can better reflect the rubber dam collapse process. Then， according to the engineering practice and flood control principle， the low-frequency flood evolution simulation is carried out for four combination schemes of seven rubber dams with incomplete collapse. The results show that flood spreads in the form of waves， and the wave crest is gradually changed in the process of propagation. When 20% frequency flood occurs， it takes 3 hours for the peak to reach the No.1 rubber dam in urban areas， and the peak flow is 1 381 m³/s. The flow distribution of the storage channel is positively correlated with the collapse height of No.1 rubber dam. No.1 dam and No.5 dam are the beginning and end of the middle dike between muddy canal and water storage canal， and local flow around the dike will occur. When the flood discharge is small， the phenomenon is more obvious. Scheme B is the optimal scheme because it can give consideration to the requirements of flood discharge and water storage， the corresponding dam collapse heights are 1.1， 1.1， 1.1， 1.1， 1.8， 1.8 and 2 m. The research results can be used as a reference for the formulation of scheduling rules for rubber dams with low frequency floods.

During the construction and operation of large-scale water conservancy and hydropower projects， the water temperature of the reservoir is an important indicator of concern. The influencing factors are numerous and interact with each other. The analysis based on actual monitoring data is time-consuming and labor-intensive， and the influencing degree and scope of each factor cannot be well distinguished. A simplified model reservoir is built as the research object， and the effects of inflow flow， inflow water temperature and air temperature on reservoir water temperature structure are analyzed by numerical method. The results show that when the inflow conditions change， the inflow flow mainly affects the area above the intake floor height. Under the condition of periodic change of inlet water temperature， the range of affected water depth increases with the increase in the period， and the maximum affected water depth is near the elevation of the intake. Under the condition of periodic temperature change， the affected water depth range increases with the increase in the period. When the temperature change period is 7， 30 and 90 d， the affected water depth is about 20 m， 25 m and the water depth of the whole reservoir. The modification of β method， which only considers the reservoir capacity above the floor height of water intake， can judge the change of water temperature structure in front of the dam more accurately.

To explore the threats to flood control standard and safety of hydro-engineering from climate change， based on the daily rainfall data of 639 stations during 1958-2017， the Pearson-III curve， least square method， F-test and other methods are adopted to study the change of design rainstorm and its response to precipitation changes in China. The results show that： ① The annual precipitation， daily maximum precipitation and design rainstorm gradually decreased from southeast to northwest under different return periods. ②The annual precipitation and daily maximum precipitation increased significantly in Southern， Central， Northwest and Southwest China （p<0.05）. And the increasing rates of annual precipitation were 0.82， 0.46， 0.24 and 0.21 mm/a， while that of daily maximum precipitation ranged from 0.02 to 0.06 mm/a. ③ Under the 20-year return period， the design rainstorm increased significantly in Central， Northwest and Southwest China （p<0.05）， and the increasing rates were 0.19， 0.05 and 0.15 mm/a， while that in South China （0.03 mm/a） and East China （0.10 mm/a） showed no significant increasing trend. There was a significant decreasing trend of design rainstorm in North China （p<0.05）， and the decreasing rate was -0.08 mm/a， while that in northeast China had no significant decreasing trend （-0.03 mm/a）. With the return period， the change rate present “increasing more and more， decreasing more and more”. ④ There is a significant positive correlation between design rainstorm and average annual maximum daily rainfall. Under a certain return period， the design rainstorm will increase with the daily maximum precipitation， which may reduce the actual flood control standards. It is necessary to revise the defense standards of existing projects. The results can provide theoretical and practical support for engineering design standard revision， flood control and disaster reduction in China.

Taking the Panlong River Basin as the study area and using the SWAT model， by setting different extreme land use scenarios， this paper analyzes quantitatively the order of contribution of main land use types in the basin to runoff， and the specific impact of vegetation cover changes on the runoff process in the basin， and further discusses the influence of basin water replenishment project and runoff in high and dry seasons on the runoff of the Panlong River. The results show that： ①The contribution of the three land use types of woodland， grassland and cultivated land to the river runoff production in the basin is： cultivated land is the strongest， followed by grassland， but it is roughly equivalent to the impact of cultivated land on runoff formation， while forest land is the weakest； ② From 2007 to 2014， the vegetation cover structure in the Panlong River Basin changed significantly. Among them， the area of forest land decreased by 7.31%， while grassland and urban construction land increased by 5.05% and 2.82% respectively. Most of the reduced forest land was converted into grassland and urban construction land.Although the ebb and flow of forests， grasslands， and urban land enhances the runoff effect， it aggravates the annual variation of runoff and weakens the functions of vegetation in the watershed to conserve water and regulate runoff. ③ After the water replenishment project was put into operation， the annual runoff of the Panlong River showed a large increase in 2014， which was completely opposite to the annual decrease trend from 2007 to 2013， and the runoff increase in the dry season was significantly higher than that in the wet season， and the runoff regulation effect was obvious. ④ The change of the runoff in the dry season is the main reason for the change of the annual runoff trend of the Panlong River from 2007 to 2014.

In order to study the spatial and temporal distribution characteristics and driving factors of historical mountain flood disasters in Jiangxi Province， this paper analyses the data of historical mountain flood disasters from 1951 to 2015 in Jiangxi Province by using the methods of standard deviation elliptic， Global Moran’s analysis， Anselin Local Moran’s analysis and geographic detector. Taking ten-year as a period， this paper selects two recent periods（1996-2005 and 2006-2015） to analyze the change pattern of driving factors in Jiangxi Province by using geographic detectors. The main findings are the following： ①The centers of mountain flood disasters in different decades are mainly distributed in the central part of Jiangxi Province， showing a southwest-northeast pattern，the overall distribution of mountain flood disasters shrinks in the north-south direction with time. ② The spatial autocorrelation analysis indicates a positive spatial correlation between the amount of mountain-flood disaster and ARD （average rainfall during historical mountain-flood disaster） in rural areas. The cluster of high ARD is formed in the central， east and northeast areas of Jiangxi Province. ③ Of all the driving factors， rainfall has the strongest explanatory power for historical mountain flood disasters in Jiangxi Province， among which the highest explanatory power is the maximum 6-hour average rainstorm， and there is a bilinear enhancement relationship between rainfall factors. Among other driving factors， elevation， slope， landform type and land use have higher explanatory power. ④ After the interaction between the maximum 6-hour average rainstorm and other driving factors， the explanatory power is greatly improved， and the interactive explanatory power with the annual rainfall factor is the highest. ⑤ In the driving factor detection at different time periods， the explanatory power of rainfall and landuse increase with time， while the explanatory power of natural geographical factors are relatively stable. The results provide a theoretical basis， scientific and technological support for the investigation of the temporal-spatial distribution characteristics of mountain-flood disaster in the Jiangxi Province， which can also benefit the monitoring and early warning， the risk assessment， the prevention and control of mountain-flood disaster.

The evolution of the water yield coefficient （WYC） reflects the response of the hydrological cycle in the basin under the influence of both climate and substratum changes， and is of great significance to the efficient use and rational regulation of water resources in the basin. In this study， we used the one-dimensional linear regression analysis and the Mann-Kendall test to identify the trend of the time-series data of water yield coefficient in the Yiluo River basin， and analyzed the spatial and temporal distribution and change characteristics of water yield coefficient based on the spatial cluster analysis method， combined with precipitation characteristics， land use types and normalized difference vegetation index （NDVI） data. The results show that the variation of water yield coefficient in the Yiluo River basin during 2001-2018 was small， with a tendency rate ranging from -0.05/10 a to 0.03/10 a； The average water yield coefficient in the section of the Yiluo River from Luoyang to Zhengzhou from 2008 to 2018 is 0.24， which was smaller than the national average （0.4）， with the highest value occurring in the urban area of Luoyang （0.41）； The trend of water yield coefficient is mainly influenced by precipitation， and land use/cover changes in different regions will have different effects on evapotranspiration， which in turn will affect the trend of water yield coefficient. The spatial distribution of water yield coefficient is more correlated with precipitation characteristics， and less correlated with land use type and vegetation cover. The correlation coefficients of water yield coefficient with precipitation， rainstorm days and vegetation cover are positive and negative， but the correlation coefficients with rainstorm days are low. The findings of this study provide a scientific basis for the deployment and utilization of water resources in the Yiluo River basin.

At present， due to a shortage of water resources and a sharp increase in the utilization of freshwater resources，research on water resources utilization efficiency is of great significance to regional economic development， water security and sustainable development of human society. Therefore， it has become a hot subject of academic research. By using Data Envelopment Analysis （DEA） Method and based on the utilization and distribution of water resources in Jiangxi Province， this paper selects capital， labor and water resources as inputs and gross regional products as output. The spatial-temporal evolution of water use efficiency in Jiangxi Province from 2008 to 2018 is studied， and the driving factors affecting water use efficiency in Jiangxi Province are analyzed with geographical detectors. The results show that：① From 2008 to 2018， the total water consumption in Jiangxi Province showed an inverted U-shaped fluctuation， with agricultural water accounting for the largest proportion， reaching more than half. ② At the temporal level， the comprehensive efficiency and scale efficiency of water resources utilization in Jiangxi Province showed a decreasing trend， while the pure technical efficiency showed a slow increase. From the spatial distribution results， the spatial distribution of the three efficiency showed the trend of northern Jiangxi > Southern Jiangxi > Central Jiangxi. ③ Geographical detector results show that social technology factors （urbanization rate） and natural factors （precipitation， surface water and underground water resources） are the main driving factors affecting the utilization efficiency of water resources in Jiangxi Province. ④ The results of interaction factor detector show that the interaction between the two factors is beneficial to improving the influence of single factor on the utilization efficiency of water resources in Jiangxi Province， and the environmental regulation factor is the most obvious. The results of this study have an important practical significance for improving the utilization efficiency of water resources in Jiangxi Province， formulating water resources policies suitable for the development of cities according to local conditions， and improving the sustainable development ability of cities.

The characteristics of the underlying surface such as vegetation coverage showed significant seasonal changes during the wet and dry seasons， The same water extraction method can obtain different extraction results in different seasons； At the same time， the mountain water body is located in the valley， easily affected by the mountain shadow， and the river water body is long and narrow， easy to appear the water body line breaking phenomenon. In order to solve the above problems，China madeGF-1 remote sensing images were used in this paper. Firstly， the application effects of single-band threshold method， Normalized Difference Water Index and Shadow Water Index on mountain channel water extraction in typical months of wet and dry seasons were compared， and the most applicable extraction methods were determined respectively in wet and dry seasons. Then， based on DEM data， considering the sun height and radiation angle in remote sensing image， the mountain shadow layer is generated， which is superimposed with the water body obtained by the above method to eliminate the influence of mountain shadow； Then， based on the DEM data， the river network is extracted and superimposed with the water extracted by remote sensing to eliminate the influence of small patches of scattered water （such as ponds）. Finally， the dilation filtering and image thinning are applied to fill the broken line. The results show that the single band threshold method and Shadow Water Index method are suitable in wet and dry seasons.Through the removal of mountain shadow， the elimination of scattered water bodies， the application of dilation filtering and image thinning to fill the broken lines of water bodies， the overall accuracy of water extraction in the wet and dry seasons respectively reached 99.52% and 99.27%， the Kappa coefficients were 0.98 and 0.97 respectively， Accuracy up to the optimal grade standard of "excellent". This method can effectively solve the bottleneck problem of river water extraction in mountainous area under different extraction background in wet and dry seasons， it lays a good foundation for the subsequent application of remote sensing technology to obtain other water information （such as pollutant concentration）.

In order to analyze the water resources output efficiency of each city in Jilin Province from 2009 to 2019， from the aspects of “water resources conditions-water use situation”， “water resources conditions-economic situation”， and “water resources conditions-economic situation”， the water resources utilization efficiency of 9 prefecture-level cities in Jilin Province is analyzed by DEA model and Malmquist index model. The results show that from 2009 to 2019， the output efficiency of water resources in Jilin Province was DEA invalid， and the scale efficiency was the main restrictive factor of the output efficiency ofwater resources in Jilin Province. From 2009 to 2019， the total factor productivity index of cities in Jilin Province showed a rising trend， and the main reason for the change of total factor productivity index is technological change. The scale effect of water resources output should be increased properly， and the utilization efficiency of water resources should be improved constantly. The output efficiency of water resources is greatly affected by the progress of technology.

To understand the characteristics and quantitatively simulate the runoff on red soil slope with different coverings， the precipitation-runoff data on red soil slopes with three coverings （bare land， planting Paspalum notatum， mulching with Paspalum notatum） from 2016 to 2017 are obtained by Jiangxi provincial Scientific and Technological Garden of Water and Soil Conservation. A numerical runoff model is constructed based on the kinematic wave equation and the Green-Ampt infiltration equation. The model uses the Preissmann difference method for spatial discretization， which is then verified by experimental data and further used to simulate the runoff and infiltration process of slope land with different coverings and rainfall intensity. The results show that： ① Compared with the bare land， mulching with dried grass or planting Paspalum notatum significantly reduced the runoff amount under different rainfall conditions， and the average reduction rates were 82.5% and 87.9% respectively； ② The relative errors between the simulated results from the proposed model and measured value of runoff were within ±10% ， which showed that the model could reflect the runoff law of red soil slope with different coverings and different rainfall conditions； ③ The numerical tests showed that coverings in soil surface could increase the infiltration and delay the start of runoff， while the delay effect decreased with the increase in rainfall intensity. The initial infiltration rate is directly proportional to the rainfall intensity， while the steady infiltration rate is less affected by the rainfall intensity. The increase in rainfall intensity can shorten the runoff duration before the stable stage. This study can provide a theoretical basis for quantitative evaluation and control of soil erosion in red soil slopes.

Based on the geological data revealed during the excavation of the underground cavern of Dagangshan Hydropower Station， a two-dimensional finite element model of fracture network is established. Considering the randomness and statistical distribution characteristics of the deformation of the fracture surrounding rock， a displacement inversion analysis method based on the fracture network finite element is formed. The forward calculation results based on the inversion mechanical parameters are basically consistent with the geological survey and the surrounding rock stability evaluation during the construction period， which can reflect the main deformation characteristics and instability mechanism of the fractured surrounding rock. It shows that the fracture network model established in this paper and the correlation inversion analysis method have good adaptability in engineering. It is found that the shear and opening deformation mainly occur in the process of excavation and unloading of the fracture structure surface， among which the stress relaxation of the gently inclined structure surface has a great influence on the surrounding rock， and the stress relaxation area is basically the same as the area where the surrounding rock loosens， which shows that the shear opening deformation of the fracture surrounding rock during the excavation and unloading process is the main reason for the stress relaxation of the surrounding rock.

According to the distribution characteristics of the monitoring data of hydropower units and the fact that a single monitoring index cannot fully reflect the overall operating status of the unit， a unit status evaluation model based on comprehensive weighting and Gaussian threshold is proposed. First of all， a unit level analysis system is built based on unit type and measurement points， and the comprehensive weighting method is used to determine the weight of each component in the system. Secondly， the statistical distribution of various types of monitoring indicators of the unit is analyzed， and the upper and lower limits of the indicators is determined based on the principle of Gaussian threshold for vibration and other indicators that conform to the normal distribution， and the temperature indicator limits are determined according to regulations. The index limit is divided into four intervals： good， qualified， attention， and abnormal， and the real-time monitoring index degradation degree is calculated according to the index limit and the interval in which the limit is located， and then the index health score is obtained. Finally， combined with the unit level analysis system， the scores of each index are weighted and calculated to obtain the overall score of the upper-level indicators of the unit， and the status of the unit is judged according to the score. Taking the actual power plant unit as an example， the model is verified， and the results show that the model can accurately determine the operating state of the unit， and the evaluation result is consistent with the actual operating situation.

In order to study the influence of reservoir water level sag combined with intermittent rainfall on the seepage stability of reservoir bank ancient landslide， based on the unsaturated seepage principle， considering different rates of reservoir water level sag， different types of intermittent rainfall and rainfall occurrence time， Geo-studio software is used to carry out finite element simulation on the seepage characteristics， displacement， deformation and stability of the landslide when the reservoir water level plummets and meets intermittent rainfall. The results show that the pore pressure rises and falls intermittently under the static reservoir water level. The pore pressure in the middle reaches the maximum and occurs at the latest. At this time， the surface displacement is maximum and shallow landslide is easy to occur. There is a positive correlation between the plunge rate of reservoir water level and the dissipation rate of pore pressure. There is a surface landslide risk in the middle and upper part of the reservoir， and a deep landslide trend in the lower part of the reservoir buried 20~25 m. The earlier the rainfall occurs， the faster the pore pressure reaches the peak. The intermittent rainfall in the early stage of reservoir water level plummeting mainly affects the displacement deformation of the upper part of the landslide， while the intermittent rainfall in the late stage of plummeting has a significant impact on the displacement deformation of the middle and lower part of the landslide. The minimum safety factor of each rainfall type is in the order of wing type > ascending type > center type > descending type， and the influence degree of landslide safety and stability combined with reservoir water level is in the order of intermittent rainfall coupled with reservoir water level descending > intermittent rainfall coupled with static reservoir water level > simple reservoir water level plummeting.

Hydropower is a clean energy with flexible regulation. It plays an irreplaceable role in maintaining the stability of power system and ensuring power quality. With the further increase in renewable energy such as wind and solar in the power grid， the traditional hydropower unit control strategy is difficult to meet the requirements of dealing with various complex working conditions. Although the theoretical research on advanced control strategy is relatively mature， its application is limited by the complexity of algorithm and practical conditions. Therefore， based on the traditional PID control， this paper uses intelligent optimization algorithm and neural network to search optimal PID control parameters under different working conditions， and designs an adaptive PID controller suitable. The simulation results show that， compared with traditional fixed PID controller， the adaptive controller designed in this paper can automatically adjust the PID parameters and maintain the optimal control performance under different working conditions.

Nianpanshan water conservancy and hydropower project adopts BIM Technology to carry out forward collaborative design， establishes project level BIM application standards， and explores and studies the three-dimensional collaborative design process of various disciplines. In the three-dimensional collaborative design framework based on BIM Technology， the main application points of Bim in the design stage are displayed through structural parametric design， collision detection， equipment operation simulation， simulation calculation， 4D construction simulation and three-dimensional technical disclosure. Through innovative attempts， we have realized the verification of key information of the project by superimposing BIM model with UAV forward photography， developed the automatic layout of pile foundation and three-dimensional rapid reinforcement tool of concrete structure by using dynamo visual programming， and built a web BIM + GIS management platform to provide data information services for design and Engineering Management. The practice shows that BIM Technology provides comprehensive and effective help for the construction of Nianpanshan water conservancy and hydropower project， improves the design efficiency and design quality， and makes a good demonstration for the application of BIM Technology in water conservancy and hydropower projects.

According to the local existing sand and gravel aggregate characteristics， the upper and lower wrapping lines of filter media are designed and equipped with filter media. The “filling fine material” of anti-seepage soil is used to protect the “filling fine material” of anti-seepage soil， and the gap of the “skeleton coarse material” just filling the anti-seepage soil is used as the design basis， which is in line with the principle of designing the “fine part” of wide-graded anti-seepage soil in the Design Code of Roller Compacted Earth-Rock Dams so as to ensure that the anti-seepage material can fulfill the basic functions of drainage， anti-filtration， self-healing after cracking and self-stabilization. Before the design of the construction drawing， the physical properties of the artificial and natural sand and gravel aggregates available in a certain local area should be screened clearly， and the first and second materials with the best gradation curve should be selected so as to design the upper and lower envelopes of the filter material which are in line with the local reality. During construction， the filter material between the designed upper envelope and the lower envelope was prepared by screening several local sand and gravel aggregates， freely combining and adjusting the proportion of each component.

Vibration signal of hydropower unit is an important content of health state evaluation and deterioration early warning. An accurate prediction of unit vibration change trend can improve the safety and reliability of unit operation. In view of the problem that single model is difficult to obtain the optimal prediction results， a CNN-BiGRU combination model vibration prediction method is proposed. Firstly， the convolutional neural network （CNN） is used to extract the local features of the data， and then the CNN-BiGRU combined prediction model is constructed in parallel with the bidirectional gated cyclic unit （BiGRU） network. The model aims to improve the prediction accuracy and universality by combining CNN’s ability to adaptively extract local information with BiGRU’s time series prediction advantages. Finally， the prediction of axial vibration peak value of a domestic hydropower station unit is studied. The experimental results show that the proposed combined model can effectively predict the variation trend of unit vibration， and provide a new idea for vibration prediction of hydropower units.

Fluid excitation force on a runner is an important factor affecting unit stability. The structure and arrangement of the guide vane are crucial to the formation of the flow pattern in front of the runner. A three-dimensional numerical model of the whole channel system of the power station is established， calculating and comparing the influence of different guide vane number arrangements on the vibration of the unit under the same boundary conditions. The calculation results show that the vibration instability of the runner will be significantly increased with fewer fixed guide vanes. Specific manifestations are as follows： Vorticity increases near the top cap and the upstream surface of the movable guide vane. When frequency is the passing frequency of the runner blade （32 Hz）， the torque amplitude is 4.83 times， 2.75 times of X radial force amplitude and 4.63 times of Y radial force amplitude.The stator-rotor interaction between guide vanes and runner is strengthened by fewer fixed guide blades so that half of the guide vane unit has an additional vibration of twice the pass frequency of the blade.

Establishing an environmental management system that meets the certification of international organizations is the main way for state-owned enterprises to improve their own management level， establish an environmental protection image and enhance the international public reliability and influence. Due to different management concepts， state-owned enterprises have the disadvantages that the evaluation elements are not clear and cannot be organically combined with the existing management system in the process of international standard certification. Therefore， on the basis of reviewing the construction process of environmental management system， this paper systematically analyzes the evaluation elements and scoring standards of international organizations on environmental management system. Furthermore， an environmental management system for overseas hydropower projects of state-owned enterprises is established.

The “small hydropower cleanup and reform” is a pioneering work without precedent， simple “one-size-fits-all”， “demolition， off”， not only hurt the interests and feelings of small hydropower owners， but also to achieve the original purpose of the reform. The original purpose of the reform was not achieved. This paper proposes that the aim is to better realise the aspirations of the people around small hydropower for a better life and to solve the contradictions of inadequate and unbalanced development of small hydropower， and to promote the long-term and healthy development of small hydropower in the direction of green transformation and modernisation. It also aims to transform and innovate the regional small hydropower intensive operation and management model by separating ownership and operation rights， and to promote the effective combination of a competent government and an effective market in the small hydropower sector. The new approach will provide a more effective means of addressing the “small hydropower clean-up and renovation” issue and provide fertile ground for the high-quality development of small hydropower in the context of “double carbon”.