The localization of Priestley-Taylor reference crop evapotranspiration model coefficients is the key to improving the accuracy of regional evapotranspiration simulation. In this paper, the farmland in the low hilly red soil region of Jiangxi Province is taken as the research object. Based on the observation data of the large aperture scintillator, the water and heat flux characteristics of farmland at different time scales are quantitatively studied by the path analysis method. At the same time, the Priestley-Taylor model is used to simulate the evapotranspiration of the red soil region, and the measured evapotranspiration is compared. The coefficients of the model are modified to evaluate the local evapotranspiration of the P-T1.26 and P-T1.07 model. applicability. The results show that the curve of water-heat flux in farmland is unimodal and is affected by weather conditions on a daily scale. The net radiant flux, latent heat flux and soil heat flux decrease at a monthly scale. Rn, T and VPD are the dominant factors affecting latent heat flux, both of which promote the latent heat exchange. P-T1.26 simulated evapotranspiration is 13.77% higher than the actual measurement, and P-T1.07 simulated evapotranspiration is 3.39% lower than the actual measurement. The P-T1.07 model with modified parameters has a significantly improved simulation accuracy, and α=1.07 can be used as a suitable localization parameter for the Priestley-Taylor model in the study area.

In order to study the influence of maximum thickness position and maximum camber position of airfoil on the hydraulic performance of the axial-flow pump, the design parameters of axial flow pump vane is adjusted on the basis of Joukowski airfoil. Through the method of numerical simulation, the influence of the maximum thickness position and maximum camber position on the hydraulic performance of the axial flow pump is analyzed. Firstly, based on the maximum thickness position and the maximum camber location of the airfoil, a single-factor analysis is carried out on the axial-flow pump, and the other design parameters of the axial-flow pump remained unchanged. Different impeller models for numerical simulation calculation are created. Secondly, both the maximum thickness position and the maximum camber position are taken into consideration in the design of the vane. Finally, the optimal design result is selected to analyze its hydraulic performance under different working conditions. The design results show that the ideal value range of the maximum airfoil thickness position is (0.175~0.25) L, and the recommended value range of the maximum airfoil camber position is (0.6~0.7) L. At the same time, it is found that when the parameter κ is within the range of 0~0.07, the comprehensive performance of the pump is better. This paper serve as a certain theoretical basis and design basis for the design of axial flow pumps.

Based on the PIV model test, the flow pattern of each section with or without triangle-revetment and vortex eliminator under the design condition of Bangladesh's Dasharkandi Pump Station is analyzed, and the improvement effect of installing triangle-revetment under the water retaining plate and installing vortex eliminator under the submersible pump on the flow pattern is verified. The PIV test is used to compare and analyze the flow patterns of each section of three pumps and two pumps when they are running. Taking the uniformity of velocity distribution and the weighted average angle of velocity as the objective function, it is concluded that the inflow flow patterns of two pumps are improved when they are running. However, small vortices are formed under the L-shaped baffle, and the distribution of flow patterns is asymmetric under the suction port of the pump.

In order to investigate the influence of impeller near wall grid and different turbulence models on numerical results of the shaft-well tubular pump external characteristics, this paper builds seven different first-level grid height impeller grid schemes based on the ANSYA CFX platform. The area average y+ characterizes the height of the entire first level grid center to the impeller wall. The standard k-ε turbulence model and SST k-ω turbulence model are used to match different impeller grid schemes.For different flow conditions,the relative error between the numerical simulation results of the energy characteristics of the shaft-well tubular pump and the model experiment results is analyzed. The results show that the head and efficiency errors of all schemes are respectively below 0.11 m and 3.72%.When the radial radius or the flow rate is larger, the value of y+ on the wall will be larger. SST k-ω turbulence model is extremely dependant on the near wall grid. However, when the average y+ of the grid is less than 20,the simulation result is highly close to the experimental value, its external characteristic relative error is half of the standard k-ε turbulence model's. For standard k-ε turbulence model, when the average y+ is more than 30, its external characteristic results are more accurate and stable than those of the SST k-ω model.This study provides a reference for the near-wall mesh processing and turbulence model selection in the numerical simulation of vertical tubular pumping equipment.

Based on the common Kriging interpolation method of geostatistics, this study analyzes 631 factors based on ET0, temperature, wind speed, relative humidity, solar radiation, rainfall and other influencing which are basic and general ground meteorological observation stations by using climate tendency rate, fractal, rescaled range analysis method and linear regression method in China. The results show that ET0 tends to decline but in Potential, Ningxia, Shaanxi, Shanxi, Northeast and other regions, ET0 increases at the rate of 0.01~28.61 mm/(10 a), which is not significant. The change complexity of ET0 is relatively small. In West China, the change complexity of solar radiation is greater than that of rainfall, while it is the opposite in East China. The Hurst index of ET0 and solar radiation is between 1.0 and 0.5, which is consistent with the past. The Hurst index of rainfall in the west of Heilongjiang and the middle of Inner Mongolia is under 0.5, and the trend of changes of rainfall in the future is in contrast to the past.

In order to study the microscopic dynamics of ultra-high molecular weight polyethylene (UHMWPE) in salt water transportation, this paper uses CFT-I material surface performance comprehensive tester in salt water lubrication friction environment. UHMWPE samples are subject to rotational friction, scanned by scanning electron microscope (SEM) and surface profiler and analyzes the speed of 500 r/min, loads of 30、50、70、90、110 N, duration 10 min; speed is 500 r/min, load is 110 N, duration is 10 min; speed is 500 r/min, load is 50 N, duration is 25 min; speed is 1 100 r/min, load is 50 N, duration is 10 min; the effect of variable factors on the friction and wear properties of UHMWPE with a rotational speed of 1 100 r/min, a load of 110 N and a duration of 10 min. The results show that the wear and load of UHMWPE under salt water lubrication is relatively large. The precipitation of salt crystal particles during the friction process acts as a ball, and the wear of UHMWPE in salt water transportation can be reduced within a certain pressure range. The particle hardness calculation model is used to analyze the relationship between the indentation depth, the hardness of the particles and the external load. The external load pressure range can be estimated when the ball acts, and to make a theoretical basis for the application of UHMWPE material in salt water environment, and the friction of other pipes in similar water conveyance environment. The situation is provided as a reference.

In order to explore the distribution characteristics of soil oxygen in the root zone of apple trees under different pit depths of water storage pit irrigation, 7-year-old apple trees on dwarf stock are used as experimental materials and pit depths are set as control factors. The soil oxygen content at different radial positions from the trunk and different vertical positions from the surface of the earth is measured by the soil in-situ oxygen detector. The results show that the soil oxygen saturation decreases exponentially with the increase in soil depth and first increase and then decreases with the increase in radial distance. In the same vertical and radial position, the soil oxygen saturation of 60 cm pit depth treatment is higher than that of 40 cm pit depth treatment, and the influence range of 60 cm pit depth treatment on soil oxygen saturation is wider. Based on this, one-dimensional vertical, one-dimensional radial and two-dimensional spatial exponential distribution models of soil oxygen saturation under different pit depth treatment are established, and the simulation results are good. The research results can improve the theory of water storage pit irrigation and serve as a theoretical guide to the selection of the depth of water storage pit irrigation.

In order to manage and control the amount of irrigation water effectively, our country has formulated a series of policies and measures to establish a precise water measurement system and supervision measures for irrigation water from the source area to the final receiving unit since the 13th Five-Year Plan. A full-featured intelligent measurement and control integrated gate which collects water level and flow data collection, gate remote automation control, solar power, wireless communication device is developed, and it is applied in the irrigation area. The results show that the integrated gate monitoring system performs remote automatic irrigation control and adjustment through the platform and the self-learning PID control mechanism is used to achieve dynamic water regulation. The system increases the control accuracy and timeliness of water distribution and distribution, and solves the problem of channel end control. It can not only improve work efficiency and reduce work intensity, but also provide a strong information support for saving irrigation water and optimizing water distribution scheduling.

This paper introduces a set of channel control integrated system which successfully developed by using fluid mechanics, communication and information control technology. After field trials, the automatic measurement data and manual measurement data proved that the water level and flow measurement accuracy meet the requirement, and it has the characteristics of high operability, low cost and low power consumption. The application of the system in the GanFu Plain irrigation area of Jiangxi Province had shown that the installation of the channel control integrated system with using intermittent irrigation mode，not only saved manpower and material resources, but also increased labor productivity and grain output, saved irrigation water consumption.whatever,it provided a reliable basis for scientific management and decision-making of irrigation water in irrigation districts, and is an inevitable choice for promoting the modernization of irrigation districts.

In order to study the effect of different clearance reflux angle on the hydraulic performance of the full-flow pump, the three-dimensional numerical simulation of the full-flow pump is carried out by using CFX software, and the internal flow pattern and performance of the full-flow pump under different clearance reflux angles are analyzed. First, according to the initial scheme, the two kinds of clearance reflux angles are designed and a numerical simulation is carried out, the inner and outer characteristics of the full-low pump are analyzed, and the reliability of the numerical simulation is finally verified by the model test. The results show that the main flow near the inlet rim of the impeller is affected by the clearance reflux, the axial velocity decreases and the radial velocity increases. The clearance reflux angle follows the direction of the flow field in the impeller, and the flow rate at the inlet of the impeller has little effect on the flow field at the inlet of the impeller. Under the low flow conditions, the flow field inside the impeller is not stable, and the clearance reflux has a great influence on the inlet rim of the impeller, so avoid running the pump under low flow conditions. However the change of the reflux angle can affect the shaft power of the full-flow pump, the friction torque between the disks is increased, the shaft power is increased, the efficiency is reduced, and the pressure distribution of the impeller outlet is also influenced, and the work power of the water pump impeller is influenced. This paper is of great theoretical and practical significance to the optimization of the full-flow pump.

The flood diversion and storage area directly suffers a large inundation loss when undertaking the task of flood diversion. Taking the Dujiatai flood diversion and storage area in Hubei Province as the study case, using a combined method of investigation and comprehensive analysis, this paper analyzes the changing characteristics of flood storage operation loss through introducing property loss coefficient and flood-hit population coefficient, and preliminarily discusses the strategies for promoting flood storage area construction based on the changes in its utilization probability. The results reveal the following points: The property loss and flood-hit population caused by flood area operation both increase significantly with time, and the growth rate of property loss is larger than that of flood-hit population. The reduction of utilization probability of flood storage area in the main stream and tributaries of the Yangtze River, directly reduces the probability and severity of the flood losses caused by flood storage area operation and raises the flood control level in flood storage area. By providing special policies, enhancing guidance, strengthening construction of flood control facilities and completing the compensation mechanism of flood storage area operation, the comprehensive flood control and security capacity can be improved and the smooth operation of flood storage area can be ensured.

It is clearly necessary to establish a precise subsidy mechanism for agricultural water that matches the water-saving effect, price increase and financial status in Document No.2[2016] of the State Council. When collecting and allocating subsidy system was formally implemented in August 2005, it was matched with the government precision subsidy mechanism, and it formed an effective water-saving incentive mechanism and water-saving restraint mechanism in practice, so as to ensure the long-term effective implementation of the system. This paper selects a typical village, analyzes the process of system formation, the profit and loss of each water user after its implementation, and the attitude of the water user to the system from the perspective of economic interests, and concludes that a simple incentive system cannot guarantee the implementation of the system. Only the joint role of incentive and restraint mechanisms can guarantee the operation of the system. However, the core of this restraint mechanism is moral restraint, and its formation should be subject to certain conditions.

In order to explore the mechanism of the influence of drip flow, soil bulk density and initial soil moisture content on the water infiltration characteristics of Hetian wind sand soil, wind sand soil from Hetian is used and the laboratory single point source infiltration experiment is carried out. The experimental results show that there is a power function relationship between the migration distance of the wetting front and the infiltration time. Under the same total irrigation amount, the drip flow has little effect on the horizontal migration distance of the wetting front, but in the vertical direction, the small drip flow is more conducive to the deep migration of water, and the soil dry bulk density is positively correlated with the horizontal migration distance of the wetting front, but negatively correlated with the vertical migration distance. The initial water content has a certain influence on the development of wetting body, but it is not obvious. In the design and management of drip irrigation system for wind-sand soil in Hetian. If the irrigation quota is fixed, the drip flow rate should be increased appropriately to avoid deep leakage.

In addition, the SCL impermeable film of the inner lining of the tank shell has been applied in the upgrading of the water project of Hongsipu in Ningxia, which can effectively reduce the project investment and increase the construction speed. However, the effect of SCL impermeable film on the reduction of flow has not yet been verified. Through the measurement of the geometric dimensions of the flow section, the hydraulic slope drop, and the multi-section hydraulic element measurement, the roughness rate of the aqueduct is calculated according to the constant non-uniform flow state of the open channel before and after the engineering transformation. The effect of SCL impermeable film on the reduction of flow is analyzed. Provide technical basis for the renewal and renovation of the follow-up project. The results showed that the roughness of the aqueduct can be reduced to 0.011 5~0.012 0 for the inner lining of the SCL impermeable film. Compared with the original concrete tank shell, the roughness can be reduced by 0.001 17~0.001 82, which can be reduced by 8.86%~13.62%. The overflow capacity of the aqueduct can be increased. 9.75%~14.99%.

In order to study the influence of different guide vanes on the hydraulic performance of axial flow pumps, based on Reynolds time-averaged N-S equation and standard k-ε turbulence model, CFX software is used to simulate and calculate the model of axial flow pumps with guide vanes of 5,7 and 9 respectively, and the hydraulic losses of guide vanes and outlet pipes under different schemes are analyzed and handled. The numerical simulation results show that the hydraulic loss of the guide vane increases with the increase in the number of guide vanes when the number of impeller blades is fixed at 4 pieces, and the hydraulic loss of the outlet pipeline decreases with the increase in the number of guide vanes under the condition of small flow rate, while the hydraulic loss of the outlet pipeline decreases with the decrease in the number of guide vanes under the condition of large flow rate. Finally, the reliability of numerical simulation is verified by a model test, which provides a reference for selecting the guide vane number of axial flow pump in the future.

The study of water resources security is a significant scientific issue in the rational allocation of the water resources and the construction of ecological environment. The Shule River Basin is selected as the research object. Based on the data of natural, economic, social and water resources from 2005 to 2017, a comprehensive evaluation index system consisting of 20 evaluation factors in 5 aspects is constructed. The multi-level and multi-objective fuzzy comprehensive evaluation model is used to comprehensively evaluate the water resources security of the basin. The results show that the safest year of the water resources security in Shule River Basin is 2015, and the most insecure year is 2011. Among them, water supply security accounts for the largest proportion in water resources security, with a weight of 0.325 7, and ecological environment security contributes to the smallest proportion in water resource security, with a weight of 0.098 4. As is listed above, based on long series time scale, the AHP and multi-level and multi-objective fuzzy comprehensive model supply a reasonable result in water resources security situation of Shule River Basin, and provide a new perspective and method for water resource security evaluation. Therefore, to improve the safety of water resources, we should continue to adjust the economic structure of the basin, improve the comprehensive utilization efficiency of water resources, formulate a reasonable water resources management system, and scientifically plan the water use structure of the basin.

Abstract: The research of water resources security is a significant scientific issue in rational allocation of the water resources and the construction of ecological environment. The Shule River Basin is selected as the research object. Based on the data of natural, economic, social and water resources from 2005 to 2017, a comprehensive evaluation index system consisting of 20 evaluation factors in 5 aspects is constructed. The multi-level and multi-objective fuzzy comprehensive evaluation model is used to comprehensively evaluate the water resources security of the basin. The results show that the most safety year of the water resources security in Shule River Basin is 2015, and the most insecure year is 2011. Among them, water supply security accounts for the largest proportion in water resource security, with a weight of 0.3257, and ecological environment security contributes to the smallest proportion in water resource security, with a weight of 0.0984. As is listed above, based on long series time scale, the AHP and multi-level and multi-objective fuzzy comprehensive model supply a reasonable result in water resource security situation of Shule River Basin, and provide a new perspective and method for water resource security evaluation. Therefore, in order to improving the safety of water resources ,we should continue to adjust the economic structure of the basin, improve the comprehensive utilization efficiency of water resources, formulate a reasonable water resource management system, and scientifically plan the water use structure of the basin.

The source region of the Yellow River is the water tower for the whole basin and the attribution of runoff variation under changing environment is important for the development and utilization of water resources in the Yellow River Basin. Based on Budyko hypothesis, the effects of climate change and other environmental drivers on runoff changes in the source region of the Yellow River are investigated and quantified. The results show that the annual precipitation in the Yellow River source area increased from 1965 to 2013, the annual potential evapotranspiration decreased, and the changes were not significant. The annual runoff series showed no significant decrease trend, and the mutation occurred in 1989. During 1990-1999, the contribution rate of climate factors to runoff reduction was about 39%~45%, and the contribution rate of other environmental drivers was about 55%~61%. In 2000-2013, climatic factors increased runoff, and other environmental drivers were the main cause of reduced runoff. Although there was no significant change in land use types and coverage during the 1980-2010 period, other environmental drivers such as the continuous downward movement of the frozen soil in the study area were the main reasons for the decrease in runoff in the source region of the Yellow River.

In the paper, the change characteristics and rules of hydrogen and oxygen isotopes of rainfall, river water and groundwater during precipitation events in Sihe River Basin of the Pearl River are studied, and the transformation relationship of rainfall, river water and groundwater are also analyzed. The results show that the slope and intercept of the meteoric water line equation of Sihe River Basin of the Pearl River in rainy season are smaller than that of the global meteoric water line, which indicates that the precipitation process has experienced certain evaporation. The average value of deuterium surplus in precipitation events decreases first and then increases, which reflects the difference of isotope fractionation imbalance caused by environmental change in the process of precipitation. There are significant differences in the hydrogen and oxygen isotopic compositions of precipitation events in different seasons. At the end of spring and the beginning of summer, the hydrogen and oxygen isotopic compositions of precipitation events are relatively enriched, and then the isotopic values are gradually reduced. In a single precipitation event, the hydrogen and oxygen isotopic values of rainfall are first depleted and then enriched. In different precipitation events, the variation range of δD and δ 18O content of rainfall is larger, followed by river water, and the change range of groundwater is the smallest. The slope of δ18O~δD relation lines of different water bodies is as follows: groundwater < river water < rainfall, and the δ18O~δD relation lines of river water and groundwater deviate from the meteoric water line, which reflects the effect of evaporation and fractionation of river water and groundwater in Sihe River Basin.

The daily runoff data of Panzhihua Station from 1966 to 2017 and the corresponding rainfall data of the nine rainfall stations in the upper reaches of Panzhihua Station are collected. The surface rainfall is calculated by the Thiessen polygon method, and the runoff variation characteristics are analyzed by Mann-Kendall mutation point test. The calculation and trend analysis of the runoff process are carried out. At the same time, the ecological indicators of ecological surplus and ecological deficit based on FDC are used to evaluate the hydrological situation of the area from the annual and seasonal scales. The results show that between 1966 and 2017, the runoff and precipitation showed a trend of “low to high to low”. The precipitation and ecological indicators of this station have a good correlation, and it shows that the change of the area's flow is mainly caused by the change of precipitation. In summer, the ecological changes in summer are more consistent with the changes in the whole year. In the period of power plant impact, the changes of ecological indicators at different scales are basically the same, indicating that the cascade hydropower station in the upper reaches of Panzhihua has little influence on the hydrological situation of the station.

The back propagation neural network (BPNN) and recurrent neural network (RNN) based sediment load estimation are constructed in the Huangfuchuan Basin according to the influence of precipitation and streamflow on suspended sediment load. Moreover, the performance of model estimations and the relative errors are further analyzed. The results indicate that: The RNN model is slightly better than that of BPNN model. Both BPNN and RNN models perform well in sediment load estimations and the CE values are higher than 0.82. The accuracy of peak sediment discharge simulation obtained from RNN model is closer to actual observations and the relative error of peak sediment discharge estimation is within 2%. The performance of BPNN model is significantly better than that of RNN model during recession periods.

Due to the significant restoration of vegetation coverage in the Yellow River Basin, the traditional Shanbei Model based on a single infiltration excess runoff module is no longer applicable to this basin. Based on this problem, an improved Shanbei model has been proposed considering the effect of the saturation excess runoff, which constructs a combination model based on infiltration-excess and saturation-excess runoff module. The traditional model and the improved model are applied and compared in the Yiluo River Lingkou Basin of the middle steam of the Yellow River respectively, and the applicability of the improved model is discussed. The results show that the improved model has higher simulation accuracy, and it is more suitable for the flood calculation in the area, which shows a certain engineering application value.

In order to improve the operation and management level of the first stage water diversion project, reduce the waste of water resources caused by abandoned water, and meet the needs of users in a timely and sufficient amount, this paper proposes a set of water scheduling system. The goal of the system is to maintain the water depth of the control point in the single canal pool near a certain target value. This goal is achieved by feedforward control based on the principle of storage compensation and feedback control using a PID controller. When the system is running, the intake water distribution plans are input into the system, and the target flow of each gate along the way can be obtained by the control algorithm. The flow of each sluice gate are directly delivered to the local control unit to achieve constant flow automatic closed-loop control. The results show that the scheduling management system can reduce the fluctuation of the water depth of the control point in the canal due to the change of water distribution plan, increase the response speed to the user's water intake requirements, and can meet the basic needs of the water volume management.

Groundwater resources are very important for the development of regional economy and society, and accurate prediction of groundwater depth is an important basis for the rational utilization of groundwater resources. Based on the long-term and short-term memory network (LSTM) model, this paper simulates the change of groundwater level with the input of groundwater level of 33 observation wells in Guanzhong area, Shaanxi Province from 2007 to 2017, and discusses the accuracy of the application of LSTM model in groundwater depth simulation. The results indicate that LSTM model can well simulate the dynamic of groundwater depth in Guanzhong area. Furthermore, the simulation accuracy in the training stage is higher than that the validation stage. Specifically, when the observed monthly groundwater depth of the 33 observation wells are simulated at the same time, no matter how many times the model is trained, the R2 is more than 0.98, while RMSE and RRMSE are both less than 5 m and 14% respectively. At the same time, the training times of the LSTM model affects simulation accuracy. The training times of the model need to match with the samples and the appropriate training times of this study is 40. In addition, the data of sample set is also the key factor affecting the accuracy of the model simulation. The simulation accuracy of all 33 wells as a sample

At present, the reanalysis datasets have become one of the important ways to make up or replace the measured meteorological data in hydrological simulation, but it is necessary to evaluate their quality and performance when they are used. In this paper, the interpolation results using meteorological interpolation software for two kinds of reanalysis precipitation datasets (CFSR and CMADS) and meteorological measured precipitation data (OBS) are evaluated in the Hunhe River Basin. Then the SWAT model is respectively driven by the above three data to evaluate their applicability of runoff simulation in Hunhe River Basin. The results show that the spatial distributions of annual precipitation of CMADS and OBS in the basin are similar, and the distributions in the year of them are consistent. The runoff simulations of SWAT model driven by CMADS and OBS are much better than that driven by CFSR. In the Hunhe River Basin, CFSR underestimates the strong precipitation and overestimated the weak precipitation, so the result of runoff simulation is poor. In general, the applicability of CMADS reanalysis data and OBS in hydrological simulation in the Hunhe River Basin is stronger.

It is of great significance to carry out joint flood control operation of cascade reservoirs in flood season to ensure the safety of downstream and water conservancy projects and realize the utilization of flood resources. In order to achieve efficient water resource operation and take into account the reservoir benefits and the safety of the reservoir and the downstream protection objects, based on the idea of space risk hedging, the distribution rules of flood storage and detention volume of cascade reservoirs are derived from “equal proportion storage”. The total amount of flood storage and detention volume of cascade reservoir system is distributed according to the proportion of the available flood control capacity of each reservoir in the total available flood control capacity of the system. Taking the cascade reservoir system composed of two virtual reservoirs as an example, the evaluation index system is established to analyze the flood regulation results of the flood storage mode and the conventional flood storage mode based on the idea of space risk hedging. The results show that the new mode can make the cascade reservoir reach the flood control high water level at the same time, reduce the system risk, improve the system benefit, and make the water level and flow process more stable after operation. It is helpful to make the ladder reservoir the operation mode of cascade reservoir joint operation has reference function.

In this paper，the AMH Copula function is applied to establish the joint distribution function of maximum 24 hour rainfall and corresponding tide level in Zhongzhu Lianwei，and the calculation method of waterlogging risk and recurrence period under different combinations of rain tides is proposed, and the probability of rain tides co-occurrence is calculated and analyzed. The probability of the occurrence of rainstorms and the occurrence of 20 years，10 years, 5 years and maximum tide level of Multi year average in Zhongzhu Lianwei is 0.02%，0.04%，0.06% and 0.10% respectively. The probability of waterlogging is 5.34%，5.61%，6.09% and 6.82% respectively. The occurrence frequency of waterlogging is higher than the frequency of design rainstorm.

With the change of global climate and the increase of extreme weather events, the situation of disaster prevention and reduction in mountainous and hilly areas of our province is extremely severe, and the early warning and prevention of mountain torrents is more urgent and important. Since the investigation and evaluation of mountain torrent disaster was launched by the national defense general administration in 2013, a total of 73 counties (cities and districts) have been completed. On the basis of summarizing the practical experience of mountain torrent disaster investigation and evaluation, this paper explores the application and improvement of instantaneous unit hydrograph, and provides reference for the improvement and promotion of this work in the future.

To describe the precipitation variation characteristics of Xiji County in recent 67 years, Mann-Kendall analysis, linear regression equation, sliding t-test, cumulative levelling curve, wavelet change analysis methods are used. According to the precipitation data of Xiji County from 1952 to 2018, the variation trend, mutation and periodicity are analyzed. The results show that annual average precipitation of Xiji is 408.2 mm, and the inter-annual and intra-annual changes are highly fluctuating. Droughts and floods are coexistent. The precipitation in all other seasons show a downward trend except in winter. There are multiple mutations in this time series, and the mutation in 1968 is the most significant. There are three change cycles of precipitation: the first main cycle is 42 years, the second main cycle is 8 years, and the second sub-cycle is 21 years. It shows that the precipitation in Xiji County will remain stable in the future. However, as a city dominated by agricultural economy, relevant sectors should pay attention to preventing disasters caused by extreme precipitation.

In this paper, the connotation of river health and sustainable utilization is analyzed according to the idea of river chief system, and the health evaluation system suitable for Su River is constructed. The structure of the evaluation system is clear and reasonable, which can analyze the current limiting factors affecting river health and quantitatively predict river health results under different treatment scenarios by 2020. The results show that the evaluation result of health and sustainable development in 2016 is 2.92, which is a state of mild health collapse. In 2020, the optimal evaluation result of river basin is 1.54, and the river is in a relatively healthy state. It shows that the river's natural property is complete and the economic benefit of the river basin is improved steadily, which can realize the sustainable utilization of the river.

Rivers and lakes sediments are adjacent to water, which also affects water quality directly or indirectly. In order to investigate the effects of grain size and nutrient characteristics of the shallow sediments on water environment and bottom nutrient environment, the grain size and related nutrient elements of the shallow sediments in different sites of Huajin River are measured, and then their potential effects on river water quality are analyzed. The results show that: ① the pH of the Huajin River shallow sediments is 7.6, and the average contents of TC, TOC, TN, TH, TS of shallow sediments are 26.2, 18.7, 2.5, 7.7 and 2.6 g/kg, respectively. C/N and H/S are 10.48 and.3.19.The grain size of shallow sediments is mainly silt, which accounts for 62%~ 83%. The content of clay and sand are lower relatively, but the content of sand was significantly different among different sampling points. ② Sediment OM varies between 29.39 and 37.24 g/kg, which is much higher than the organic pollution standard. The nutrient status of the river is at the mesotrophic and eutrophic level, which is mainly affected by water disturbance and the input of exogenous organic matter, and thus potential risks to water environment exist. ③ The grain size of shallow sediment has a great effect on its nutrient status. The sand grains of sediment are negatively correlated with TH, with a correlation coefficient of 0.68, which is only positively correlated with TS in nutrient elements. The silt grains are positively correlated with TH, with a correlation coefficient of 0.62, which is negatively correlated with TS. The clay grains are positively correlated with various nutrient indicators, in which significant positively correlated with TH and TN, with the correlation coefficients are 0.71 and 0.54, respectively. Therefore, the nutrient status and grain size characteristics of river shallow sediments can be used as important potential indicators for water environmental management.

By analyzing the pollution characteristics of rural domestic sewage in loess gully region, the characteristics of rural domestic sewage on source of pollution, dirt condition and discharge should be laid out. The pollution sources of rural domestic sewage in loess gully areas are relatively simple and tend to be consistent. For the sewage discharge, pipes or channels are constructed in the district of township government located in the natural communities where there are over 200 people. In the loess gully areas, the discharge points are in dispersion, rain and sewage is discharged together, and discharge volume of a single outlet is generally less than 300 m3/d. There is a positive correlation between the amount of sewage discharged and the amount of rainfall. During a year, the amount of sewage discharged is large in the rainy season and stable in the non-rainy season. Otherwise the interannual growth trend is slow. The rural sewage treatment technology module system is put forward to face the rural sewage in the loess gully regions having screened the existing rural sewage treatment technology, combined with the characteristics of rural domestic sewage system coming from the integrated and innovated the A/O sewage treatment equipment. Through the field test, the sewage treatment system can meet the level A requirement of the national “Discharge Standards for Pollutants from Urban Sewage Treatment Plants” (GB 18918-2002). The treatment technology system can be widely used in the loess gully regions with less investment, convenient construction and a short cycle.

To study the formation mechanism of groundwater chemistry and the influence of surface water on groundwater hydrochemistry near the Yellow River in Kaifeng City, the basic characteristics of groundwater chemical composition, Shukalev classification, piper three line graphic, and ion ratio coefficient method are used to systematically study the groundwater. The results show that the coefficients of variation of groundwater ions in the study area are basically lmore than those of surface water, in which the coefficients of variation of Na+ and Cl- are larger and the coefficient of variation of HCO-3 is smaller, the hydro-chemical types changes from HCO·SO4·Cl·Na·Ca type to HCO· Ca·Na·Mg type. The correlation coefficient between the main ions of surface water and groundwater is not significantly different, the source of Na+ is the dissolution of salt rocks and other sodium-containing minerals, Ca2+ and Mg2+ mainly come from carbonate and silicate minerals. From North to South, with the distance from surface water, the hydrodynamic effect on groundwater is slightly enhanced; the concentration of Na+ also increases slightly. The sampling sites near the railway and surface water in the groundwater are less polluted than those in the city center, besides mineral dissolution, the influence of human activities cannot be ignored.

An analysis of the change process of pollutant content in different underlying surface runoff in urban area during rainfall period can provide a theoretical basis for the more rational use of rainwater resources and reduce the pressure of water supply and demand contradiction for urban construction. Under the premise of analyzing the change of pollutant concentration of each underlying surface runoff by using the single-factor evaluation method of water quality in the residential area runoff, residential area road runway, residential road path flow, viaduct rainwater runoff and river channel, the water quality evaluation is further implemented by comprehensive water quality index evaluation method. The temporal and spatial variation of surface runoff water quality during rainfall periods. The results show that the initial pollution of the roof runoff and the residential road path is the most serious, and the initial flushing effect is obvious. The runoff water quality is better at the later stage of the rainfall. The runoff pollution of the viaduct is relatively light, the water quality of the river is poor, and a part of river section seriously exceeds the urban runoff water quality class IV water standards are not directly usable.

Tennant method as a way to calculate the ecological base flow is widely used in our country. According to the unique geographical features climate of Nandu River, Tennant method is improved by introducing season correction coefficient and using the median theory. Then the ecological base flow of Nandu River is respectively calculated by the method of traditional Tenant and improved Tenant method. Through the comparison and analysis of result show: the ecological runoff calculation result calculated by improved Tennant method is less than the result calculated by traditional Tennant method, reflected well the seasonal changes of Nandu River and removed the influence of extreme numerical calculation. It has a guiding role in he protection of ecological environment and water resources reasonable allocation of Nandu River.

In order to accurately assess the water quality and non-point source pollution in the Xiaoanxi River Basin, and provide technical support for the comprehensive improvement of the water environment in the basin,the comprehensive pollution index method is used to evaluate the water quality in different water periods in the Xiaoanxi River Basin, and the source strength coefficient method and export coefficient method are used to analyze the non-point source pollution in the basin. The results show that the overall water quality of the Xiao'anxi Basin is poor, and the evaluation factor with the highest pollution sharing rate is TN. The non-point source pollution is serious, and the main pollutant is TN, which is consistent with the water quality assessment results. The main sources of pollution are urban domestic sewage and rural domestic sewage, and the sum of the total standard pollution load is as high as 81.94%..From the perspective of townships, the pollution in the urban section is relatively heavy. The key control townships are Bachuan Street, Dongcheng Street, Nancheng Street and Hufeng Town. The spatial distribution of non-point source pollution is basically identical, and relevant prevention and control measures should be taken.

Multivariate statistical methods are used to analyze the temporal and spatial variations of 14 water quality indicators in 9 lake water sources of Suzhou from 2006 to 2017. The Nemero index method is used to calculate the comprehensive water quality status of 9 water sources over 12 years. Results show that 9 water sources are generally considered as mild pollution. The eutrophication status is on an upward trend in 12 years. and is characterized by seasonal variations during the year. The flood season (mostly mild eutrophication) is higher than the non-flood season (mostly medium nutrition). Cluster analysis (CA) and discriminant analysis (DA) results show that the water quality of 9 water sources is significantly different between flood season (July-October) and non-flood season (January-June, November, December). The water quality can be divided into Kunshan Area, Tai Lake Area and Changshu Area at spatial scale. Principal component analysis (PCA) results show that the water quality of Kunshan Area is mainly polluted by eutrophic pollution. Tai Lake Area is mainly affected by organic pollution and agricultural non-point source pollution. Changshu area is mainly polluted by nitrogen pollution. The results serve as a guide to the protection of water quality and pollution control of lake water sources.

Bangladesh's Kanapuri River Tunnel Project has the characteristics of complex stratum conditions and high degree of seismic liquefaction. In order to ensure the safety of the project, the project adopts gravel pile composite foundation reinforcement treatment scheme. However, there is no theoretical basis for the important parameters of gravel pile in this project, such as the selection of pile diameter, pile spacing, and the determination of modulus. It is necessary to conduct a full study in combination with the project to demonstrate the reliability of the foundation disposal measures in this project. In this paper, numerical analysis models of undisturbed soil foundation, single gravel pile foundation and composite foundation reinforced by gravel pile groups are established by using FLAC3D software. The influence of pile diameter on liquefaction resistance of gravel piles in single pile model and pile modulus on liquefaction resistance of gravel piles in pile group model are studied. The results show that with the increase in pile diameters, the foundation area treated by a unit of cross section area of gravel pile decrease when the site soil achieves the same anti-liquefaction treatment effect. With the difference in pile modulus, the excess pore pressure ratio of composite foundation changes little after an earthquake. Through the construction of a gravel pile, the excess pore pressure ratio of buried depth rapidly and substantially increases after reaching the peak value. The degree of liquefaction of gravel piles decreases significantly, reflecting the remarkable anti-liquefaction effect of gravel piles. The research results provide a sufficient theoretical support for seismic liquefaction disposal of Bangladesh Tunnel Project, and can also provide a reference for similar projects.

In order to study the hydraulic performance of the rotary axial flow pump, a pair of rotary axial flow pumps are designed based on the TJ04-ZL-23 axial flow pump model impeller, and the CFD method is used to perform numerical calculations and analysis on the rotary axial flow pump. The result shows that compared with the TJ04ZL-23 axial flow pump, the efficiency of the counter-rotating axial flow pump has decreased, but the head has increased by about 1 time. Compared with the axial flow pump with the same specific speed, its high efficiency area is significantly wider, about 2 times that of the axial flow pump model. The front impeller is more efficient and maintains high efficiency in a wide flow space. The designed rear impeller has superior hydraulic performance and cavitation performance. The design of the counter-rotating axial flow pump should mainly consider the cavitation performance of the front impeller. Under different flow conditions, there are positive peaks in the pressure gradient distribution on the inlet and outlet sides of the pressure surface of the front and rear impellers of the rotary axial flow pump, and on the inlet side of the suction surface. This paper systematically summarizes the performance characteristics of counter-rotating axial flow pumps, and serves as a guide for the design and application of counter-rotating axial flow pumps.

In the construction process of deep and long tunnels, it is of great significance to improve the engineering efficiency and reduce the economic loss by predicting the geological conditions in front of the working surface in advance and taking measures to avoid directly encountering bad geological bodies such as faults, caverns, soft and hard interlayers, weak broken zone and so on. At present, the True Reflection Tomography (TRT) technology has been widely used in the prediction of tunnel faults and other bad geological bodies. In this paper, the application of the new generation of TRT7000 geological prediction system in the project of a TBM water conveyance tunnel in Xinjiang is discussed. The detailed processing, analysis and on-site verification of prediction results are in combination with all kinds of geological data and the practical conditions after excavation. Besides, several problems existing during the work of field testing and post-processing are also analyzed, which will provide a feasible idea for a further research.

The permeability coefficient is an important parameter for the calculation and analysis of engineering seepage. For the multi-objective inversion problem of permeability coefficient, this paper constructs the permeability coefficient and measuring point pressure head as training samples, inversion of dam permeability coefficient by BP neural network. Optimization of BP neural network weights and thresholds by genetic algorithm, overcome the shortcomings of slow convergence and poor generalization ability of BP neural network. Finally, the GA-BP neural network multi-objective permeability coefficient inversion model is established and verified by examples. The results show that the relative error between observation point pressure head and measured value is 3.6% when the permeability coefficient of GA-BP neural network inversion is used. The result is reasonable and credible, and superior to traditional BP artificial neural network in convergence speed and accuracy.

The construction of sluice gates, the flood level along the upper reaches of the river is often raised.Therefore, measures need to be taken to offset its adverse effects. Taking the upstream construction of a city's sluice as an example, a two-dimensional mathematical model nested by size model is adopted. The changes of flood level, impact range and flood hydrograph along the two schemes are analyzed. The results show that the water level of 500~1 000 m upstream of the reservoir area is higher than that of the conventional scheme after the scale of the upper channel of the sluice gate is enlarged, but the range is not large. In the upper reaches of the reservoir area, the water level in the range of 4~8 km away from 1 km is significantly lower than that in the conventional scheme, and the flood control benefit is obvious. By enlarging the scale of the river channel in front of the sluice gate, the upstream flood level of the sluice gate can be reduced as well as the water supply requirement. The research results can be used for reference in similar projects.

The climatic characteristics of karst areas in Guizhou are favorable for the construction and crack prevention of concrete, but for mass concrete structures, it is still necessary to use simulation calculation to determine the crack resistance safety of the structures. At present, researches on temperature control and crack prevention are mostly focused on the mass concrete structure of dams, but there are few relevant researches on the large-scale powerhouse structure. Taking the powerhouse behind the dam of Jiayan water conservancy project as an example, this paper establishes a three-dimensional finite element model, simulates and analyzes the temperature and thermal stresses of the powerhouse during the construction period, and puts forward some temperature control measures and suggestions. The calculation method and relevant conclusions in this paper can provide a reasonable reference and basis for designers of similar projects.

In the construction of large-scale complex projects, due to the different nature of the sub-project and the different amount of work, the experience and proficiency of the construction personnel or team to each sub-project are also greatly different, so the configuration of the construction personnel or team to a certain extent has become an important factor affecting the construction period, cost and efficiency. At first, this paper developed a personal experience and the team concept and calculation formula of experience value, set up considering work experience and balanced construction team configuration model, design the genetic encoding structure of optimization variables, the non dominated sorting genetic algorithm NSGA-Ⅱsolving optimization according to the model. Finally, the optimal configuration of the construction team is carried out by taking an auxiliary dam project of a reservoir as an example.

Climate change has greatly changed the water cycle and the distribution of water resources. River runoff, as an important carrier of human use of natural water resources and water energy, will also be affected by climate change in the future through the water cycle. Therefore, considering the future climate change, it is of great significance to study the generation capacity of hydropower stations which can regulate river runoff and extract water energy. This paper takes Huanglongtan Hydropower Plant as an example, setting the future climate change scenario by the global climate model (GCM) simulation results, the meteorological elements after downscaling treatment are input into SWAT hydrological model to predict the future (2020-2080) inflow flow series of Huanglongtan Reservoir. After the consistency analysis with the historical (1961-2017) inflow flow series, inflow scenarios are determined for water energy calculation. The guaranteed output and average annual power generation of hydropower stations are calculated, and then the impacts of climate change on the power generation of reservoirs are also analyzed. The results show that the future inflow and the historical inflow under the climate change are inconsistent. The guaranteed outputs of Huanglongtan Hydropower Plant under the the future RCP4.5 scenario and the future RCP8.5 scenario are 59 800, 52 600 and 48 200 kW respectively, while its annual average power generation are 743 million, 779 million and 731 million kWh respectively. The impacts of climate change on the discrete degree of reservoir inflow flow increases, which reduces the guaranteed output of hydropower stations, and brings new requirements and challenges to the operation of hydropower stations.

The accelerated carbonation test and mercury intrusion porosimetry test are carried out to investigate the effect of different mixing methods, content and fineness of granite powder on the carbonation resistance of hydraulic concrete and analyze the pore characteristic of hydraulic concrete. The results show that the carbonation resistance of hydraulic concrete increases at first and then decreases with the increase in granite powder. And the carbonation resistance of hydraulic concrete is the best when 20% of granite powder is added. When the content of replacing cement with granite powder exceeds 5%, the carbonation resistance of hydraulic concrete will deteriorate gradually. Compared with the mixing method and content, the fineness of granite powder is not the main factor of affecting the carbonation resistance of hydraulic concrete. Externally adding or replacing cement with appropriate amount of granite powder can improve the pore structure of hydraulic concrete and reduce the contribution porosity of harmful pores. It is suggested that the best content of adding granite powder（fitness 0~150 μm）is 20% and the best content of replacing cement with granite powder（fitness 0~45 μm）is 5%.

Due to the requirements of the Yellow River Commission for the operation of Xiaolangdi-Xixiayuan reservoirs, the best operation scheme of the reservoirs cannot be derived accurately in formulating the power generation plan. For this reason, a reservoir group optimal operation model is constructed considering the operation order of Xixiayuan Reservoir, and a POA-GA nested search algorithm is proposed according to the characteristics of the model. The POA algorithm is used to search the demand flow sequence under the order demand, and seek the combination state of different outflow flows of Xiaolangdi-Xixiayuan Reservoirs. On the other hand, the optimal scheme of Xiaolangdi-Xixiayuan Reservoirs under different state combinations is searched by GA algorithm. The results show that the model constructed in this paper can ensure that the operation scheme of the reservoirs meet the needs of the Yellow River Committee dispatching order, and the POA-GA nested search algorithm can obtain the optimal solution in the feasible domain. The method can effectively guide the operation of Xiaolangdi-Xixiayuan Reservoirs and provide theoretical support for operators.

Deformation monitoring is one of the main safety monitoring items of concrete dams. It is of great significance to draw up scientific and reasonable deformation monitoring indicators for concrete dams to accurately identify dangerous situations and ensure dam safety. In view of the uncertainty in the deformation monitoring information of concrete dams, this paper introduces the cloud model theory, sets the level threshold of monitoring sequence evaluation by using the normal cloud expectation curve and the inner and outer contour lines, puts forward the method of Concrete Dam Deformation Safety Evaluation Based on the cloud model, and applies the M-estimator to the wave monitoring sequence with poor adaptability to the cloud model, which improves the reliability of the model. The case analysis shows that the cloud model has high accuracy for regular data, processed wave data and step data. At the same time, the model considers the overall distribution of monitoring sequence and the uncertainty of monitoring data caused by external factors, which is more applicable than traditional methods.

Due to the technological requirements and layout characteristics of thermal power plants, the tail water of once-through cooling water system usually has the characteristics of large flow and rich residual energy. Engineering practice has shown that the recovery of residual energy can be effectively carried out with the help of small hydro turbines. Combined with a coastal power plant as an example, based on the study of the drainage characteristics and the tail water residual energy of the cooling system in the thermal power plant, the scheme design and economic analysis of the tail water residual energy power generation in a typical thermal power plant are carried out. The results show that it is feasible and reasonable to use the residual energy of the tail water in the power plant, which provides an alternative solution for the utilization of the residual energy of the tail water in the thermal power plant.