With historical meteorological data during the period of 1989～ 2016 and weather forecast messages during the period of 2013－2016as the basis in six stations which are located in arid zones and humid zones in this paper,with ET0 calculated by FAO56 Penman-Monteith equation as the contrast,we compare the accuracy of ET0 prediction of calibrated Hargreaves-Samani formula ( HS) with that of symbolic regression model ( SＲ) ． Ｒesults show that the accuracy of ET0 prediction of calibrated HS formular maintains a higher level in all stations, and that its forecast accuracy is slightly higher in typical stations which are in arid zones than those in humid zones． Compared with HS formula,the ET0 forecast accruacy of SＲ model ha been improved to some extent in different climatic zones,the value of mean absolute error ( MAE) and root mean square error ( ＲMSE) of SＲ model reduced by 18．98% and 20．97% in humid zones,respectively,and the value of MAE and ＲMSE of SＲ model has been reduced by 9．79% and 7．53% in arid zones． Therefore,according to forecasting accuracy of different models ind different climatic zones,combining with climatic features,SＲ model and HS formula are recommended for predicting ET0 in humid zones and arid zones． And it can provide accurate data for real-time irrigation forecasting．

Eggplant in greenhouse was used as the test crop, and the conventional drip irrigation was used as a control. The trace irrigation technology was used to study the effects of different irrigation amounts on the growth characteristics, yield, water use efficiency and soil moisture of eggplant Impact. The results showed that with the decrease of irrigation volume, plant stem diameter decreased. At different growth stages, the stem diameter of eggplant treated with 20% lower irrigation volume than drip irrigation was greater than that of other treatments. Under different irrigation conditions, the amount of irrigation affected the length and width of the leaves. The application of trace irrigation in eggplant can save 20% -40% water and increase water use efficiency by 6.27 ~ 23.94kg / m3 compared with conventional drip irrigation, which has great water saving potential. Drip irrigation soil moisture content larger. The soil water content decreased with the decrease of irrigation water volume in the case of scar irrigation. The distribution trend of water content first increased and then decreased with the increase of soil depth.

In order to find a suitable planting pattern in the process of winter wheat cultivation in dryland,tillage methods ( no-tillage and traditional tillage) compared with irrigating time ( irrigating at jointing stage and irrigating 10 days after jointing stage ) were adopted at the Experiment Station of Shandong Agricultural University in 2015－2016 winter wheat growing seasons． The results show that compared with traditional tillage,no-tillage significantly decreased winter wheat grain yield and leaf water use efficiency ( WUEL) in flag leaves at the late growth stage of winter wheat． In no-tillage,irrigating 10 days after jointing stage significantly increased spike numbers and kernel numbers per spike,which could compensate the grain yield loss in no-tillage treatment． Considering winter wheat grain yield and leaf water use efficiency as a whole,combination of no-tillage and irrigating 10 days after jointing stage is a sound saving-water pattern in North China Plains．

In order to effectively improve the forecast accuracy of reference crop evapotranspiration (ET0) in the Northwest China, six representative meteorological stations were selected in the northwest region, and the ET0 calculated using the PM model was used as the standard value, using the daily meteorological data from 1993 to 2016. Ten extreme machine learning ET0 forecasting models were used to estimate the model generalization error by k-fold cross-validation and calculated with the four types of Hargreaves-Samani, Chen, EI-Sebail and Bristow in the northwestern region. Higher accuracy models are compared. Results show: ELM1 (input Tmax, Tmin, RH, n, and u2), ELM2 (input Tmax, Tmin, n and u2), ELM4 (input Tmax, Tmin RH and u2) and ELM7 (input Tmax, Tmin and u2) All the models have high simulation accuracy with MAE of 0.199, 0.209, 0.250, 0.273, RMSE of 0.270, 0.285, 0.341, 0.422, NSE of 0.983, 0.981, 0.973, 0.987, and R2 of 0.984, 0.982, 0.975 respectively. , 0.960. The global performance indicator rankings were 1, 2, 3, and 4 respectively; model portability analysis showed that the ELM model has strong generalization ability, in addition to the relatively low simulation accuracy of ELM7 between Dunhuang and Kashgar rivers, the MAE of the remaining models at different sites in the Northwest China was 0.40. Below, RMSE is all below 0.49, NSE is above 0.95, and R2 is all above 0.96. the ELM model has strong generalization ability; in the case of the same input The simulation accuracy of the lower ELM model is higher than Hargreaves-Samani, Chen, EI-Sebail and Bristow. Therefore, in the absence of meteorological data, the ELM model can be used as a recommended model for the calculation of ET0 in the Northwest China.

Capillary arrangement is an important parameter for mulched drip irrigations． In order to investigate the effect of different capillary arrangements on soil water,salt and yield under the mechanical harvest cotton pattern,test-pit experiments are set under two capillary arrangements． The results show that,three capillary treatment result in desalination areas fit for the growth of cotton in the main root,the soil water content is in appropriate range,has irrigation uniformity and a beneficial effect on the controlling of salt． In the two capillary tubes treatment,because of capillary arrangement among the wide row,the edge of wetting front is close to narrow row of cotton,the cotton growth is affected by water and salt stress． Because of different capillary arrangements,distribution of water and salt are different from the cause the effect on growth and yield of cotton,so obvious a difference in water efficiency is found among the two capillary tubes arrangement． Water use efficiency for three dripping pipes is 1．35 kg /m3 and is much higher than 1．28 kg /m3 for two dripping pipes． Therefore,in order to increase water use efficiency and yield,the three capillary tubes arrangement is suggested in Xinjiang．

The comprehensive evaluation of operation level of irrigation district is the basis of realizing the science and sustainable development management of irrigation district, it’s also the important decision-making basis of continuous investment and water-saving reform investment in irrigation district. This paper introduced the construction of comprehensive evaluation index system of operation level of irrigation district, studied the method of determining the weight of indicators, and compared the existing evaluation methods whose number exceeds twenty for the comprehensive evaluation of operation level of irrigation district, clarified the advantages and disadvantages of evaluation results ; Put forward that integrated evaluation index system of operation level of irrigation area should give more consideration to reflect the ecological, informatization, intelligent and sustainable development of technical indicators in the future. To build a harmonious and beautiful irrigation district based on intelligent comprehensive evaluation of irrigation operation level. Based on the new mathematical methods and models to establish a new method of integrated evaluation of operation level of irrigation districts, to develop a comprehensive evaluation platform which will guide the modernization of irrigation districts more scientifically through combine 3S and other modern information technology.

Based on the field measurements of soil moisture and water layer data,this research uses the water balance model to calibrate the variables of crop coefficient ( Kci ) ,saturated hydraulic conductivity ( K0 ) ,fitting parameters a and b and empirical constants( α) and calibrated model to determine irrigation system of“456”and“467”under the condition of“catchment period irrigation”． By comparing the effectiveness of the two irrigation systems,the results indicate that the irrigation frequency of“467”irrigation system has decreased by 2 times under different annual rainfall levels compared with the traditional“456”irrigation system,and the irrigation quota has decreased by 499．5～ 700．5 m3 /hm2,rainfall utilization efficiency has increased by 1．2% ～ 6．5%． In this manner,water can be saved and the soil moisture can be maintained within the appropriate range of crop growth． In general,the improved irrigation system( “467”) has the characteristics of less irrigation times,smaller irrigation quota and higher rainfall utilization rate,which has an important guiding significance for the optimization and adjustment of irrigation system of“catchment period irrigation”in Gaoyou Irrigation District

According to the water level data of 22 selected hydrological stations in the Poyang Lake Area,the water level series of each station after the impoundment of the Three Gorges Ｒeservoir was obtained by using the water level correlation method． Based on the water level data of each station in the two periods before the impoundment of the Three Gorges reservoir and after the impoundment of the Three Gorges Ｒeservoir,the change of guarantee rate of irrigation water intake in the Poyang Lake Area was quantitatively analyzed． The results show that after the impoundment of the Three Gorges Ｒeservoir,the average water level of 9～ 10 months in the main station of Poyang Lake Area declined obviously,the decrease was 0．96～ 2．67m． Before the impoundment of the Three Gorges Ｒeservoir,the irrigation water intake guarantee rate of 9～ 10 months in the Poyang Lake Area was 78．5% ～ 89．9%,and the weighted average value was 85．2%,which basically met the irrigation design standard． After the impoundment of the Three Gorges Ｒeservoir,the irrigation water intake guarantee rate of 9 ～ 10 months decreased to 21．0% ～ 80．5%,and the weighted average decreased to 64．4%,which was lower than the requirements of irrigation design standard．

CN values are the key to estimating runoff depth from rainfall by using soil conservation service ( SCS) method． But it＇s difficult to obtain the values of CN due to the difference in regional conditions,which are the main causes of less frequent use of the model． This paper calculates the CN values of 11 types of forest by using rainfall and runoff data of 2009－2014． The result shows: ① The CNs of all plots are above 74 for slop areas． ② There is a significant correlation of CNs with canopy density． This paper proposes a new method for CN obtainment．

The spatial and temporal distribution of rainfall in China is extremely uneven,with a wide spatial distribution and the rainstorm is relatively concentrated． Therefore,it is significant to analyze the features of rainstorm rapidly and accurately in large areas． In this paper,we propose a method based on a satellite data according to the latest online GPM IMEＲG satellite data,by synthetically using EOF,fast accumulative precipitation and spatial data interpolation method after the complete evaluation of GPM IMEＲG satellite data． The main results are as follows: ①GPM IMEＲG satellite data performs well in Hubei Province,and the correlation coefficient has reached 0．759 on the daily scale． ②The key modal identified by EOF analysis method instructs the critical precipitation． ③The calculation areas of rainstorm center using fast accumulative precipitation and spatial data interpolation method and one key modal identified by EOF analysis method are basically consistent in space distribution． The method proposed in this paper can provide a theoretical basis and scientific support for the analysis of rainstorm in the areas lacking ground rainfall stations．

To understand the role of gravel on the soil water retention,this paper uses high -speed centrifuge to measure the soil water characteristics curve of samples with two different lithologic crushed stone ( gneiss and limestone) of four ratios: 0%,10%,20%,30% and 40%． The VG ( van Genuchten) model of ＲETC software is used to analyze the soil water characteristics curve． The results suggest that ① Under the same soil water suction condition,the soil water content decreases with the increase in gravel ratios． ② Under the same soil water suction and the same gravel ratio condition,the soil water content of limestone mixture decreases more than gneiss ones． ③ VG model can be used to fit the water characteristics curve of soil and rock mixed media,soil saturated water content from the above model is just related to gravel ratios for limestone mixed media,but that is related to soil and gravel ratios for Gneiss mixed media．

A real-time correction model, based on artificial neural network theory, is developed for multi-section channel waterlevel forecasting. By integrating BP neural network and the finite memory least square method, the recursive network training and learning model is established for tracking the residual error of flood forecasting. The developed model was applied with taking the middle channel of Huaihe river as test river,. Results show that the error of channel waterlevel forecasting was decreased with ranged from 0.14m to 0.46m, and the developed realtime correction model perform well in 2008 flood season. It has certain reference significance for similar channel waterlevel forecasting.

Because of the influence of water resources development and utilization, the result of water resources evaluation based on hydrological models often deviate. Based on the characteristics of hydrologic cycle under current conditions, an improved vertical mixed flow model is proposed for water resource evaluation. The model is established by considering the impact of water resources development and utilization. On the basis of computer automatic optimization, artificial optimization parameters are carried out to increase the precision of the parameters .Parameter optimization is based on automatic computer optimization to improve parameter precision. The results show that the water resources evaluation model is suitable for water resources evaluation in the study area. The relative error is less than 20 %, and the qualified rate is 83.9 %. It provides a new method for water resources evaluation in the study area.

Hydrological simulations in no-data or data sparsely regions are now a hot issue that have drawn wide attention and discussion in hydrological field. On basis of quality-controlled daily precipitation data and hydrological data over three sub-basins in Tonle Sap Lake, the suitability of AgMERRA reanalysis products were evaluated by using statistical approach and hydrological modelling. The results show that: 1. the AgMERRA precipitation can reflect the monthly precipitation process in the study areas; 2. AWBM and Sim-Hyd model forced with AgMERRA products can well simulate the monthly streamflow over the three sub-basins which mean that these two models can be applied to the assessment of hydrological changes in the study areas; 3. both models have relatively poor simulation results for the peak streamflow in 2010, probably due to the poor consistency of the measured streamflow which may influenced by human activities.

In order to compare the effects of different treatments on the physicochemical properties and cadmium adsorption capacity of biochar, two kinds of agricultural solid wastes (pig manure, pig manure residue) were pyrolyzed at five temperatures (300,400,500,600,700℃) using two sieving treatments (before and after pyrolysis). The effects of different treatments on the physicochemical properties of biochar were investigated. The biochar was also characterized by scanning electron microscopy（SEM）, X-ray diffraction (XRD) and Fourier transform infrared spectro graph (FTIR). The cadmium adsorption capacity of biochar was determined by a batch experiment. The relationship between physicochemical properties and adsorption capacity of biochar was also analyzed. With increasing pyrolysis temperature, pH value, ash content and BET specific surface area of biochar were increased, and yield, the H/C molar ratio were decreased. The types of compounds contained in pig manure biochar were more abundant, and the adsorption capacity of pig manure biochar was larger than the pig manure residue biochar when the pyrolysis temperature rised to 500~700℃. The maximum adsorption of pig manure residue biochar reached to 23.5 mg/g, that of pig manure biochar reached to 36.4 mg/g. Yield and ash content of different biochar were significantly negatively correlated, while yield showed highly significant and positive correlation with H/C, and the ash content of biochar was positively correlated with pH value. The H/C molar ratio was important for the cadmium adsorption capacity of biochar, and the BET specific surface, ash content, O/C molar ratio were of secondary importance.

Green zero-valent iron nanoparticles ( GS－nZVIs) are synthesized by using grape seed extracts and the removal of Cr( Ⅵ) by GS－nZVIs from aqueous solution is investigated． GS － nZVIs formed with sizes from 30 to 50 nm is observed by a transmission electronicmicroscope ( TEM) ． Ｒesponse surface methodological analysis is conducted by Box-Behnken design by using three factors ( reaction time, temperature and pH) and three levels with Cr( Ⅵ) removal rate as the response value． The results of response surface methodology variance analysis show that the three factors deeply influence the Cr( Ⅵ) removal rate and fit well in the whole regression region( F = 27．09) ． It is suitable for the optimization of Cr( Ⅵ) removal conditions． The effects of the three factors on the Cr( Ⅵ) removal rate is pH ＞ reaction time＞ temperature． Pseudo first order kinetic model,pseudo second order kinetic model and intra-particular diffusion model are used to describe the kinetic behavior． The results show that the pseudo second order kinetic model has the best agreement with the experimental data．Activation energy is about 22 kJ/mol,suggesting that the process of Cr( Ⅵ) removal by GS－nZVIs is a chemically diffusion-controlledreaction．

Specific topography of the loess Plateau Ｒegion in Gansu is based on an analysis of the formation factors of torrential flood disaster．The nine factors include elevation,slope,accumulation volume,river net density,and average annual rainfall． One hour critical rainfall,population density,arable land area and per capita GDP of the study area determine the main influencing factors of torrential flood disasters．The risk zoning model of torrential flood disaster is set up by analyzing risk and vulnerability． The weight of each index was determined by the analytic hierarchy process． The spatial interpolation and raster layer of ArcGIS are used to calculate the risk regionalization of torrential flood disaster． It turns out that the comprehensive risk index of torrential flood disaster in the whole research area is divided into five grades and has the distribution characteristics of increasing from the northwest to the southeast． The high risk area is mainly distributed in Longdong Loess Plateau Area and the southwest of Linxia State,the higher risk areas are mainly distributed in the middle and south of the loess plateau,the middle area is located in the middle part of loess plateau． the lower risk area and the low danger area are distributed in the northwestern part of the loess plateau．And the frequency of 65 years historical torrential flood disasters has verified the results of the mountain flood disaster risk zoning in the loess plateau in line with the actual situation,so as to provide support for the risk management of torrential flood disaster

Straightness measurement for towing tank track determines the quality of results in ship model tests． Straightness measurement by total stations with collimation line method is economical,flexible and simple to operate． It can achieve high -precision for short track．However,it is difficult to achieve the precision we expect due to the combined effect of various factors for long tracks,especially for towing tank tracks． In this paper,total station arbitrary station method is adopted to measure straightness of towing tank tracks． The modified method of small-angle measurement is proposed,and the range of small angle is defined． According to the test results,this method can avoid the error of centralization,shorten line-of-sight distance,overcome intervisibility,and improve measurement accuracy． This method is also easy to operate and low-cost． Therefore,it has a widespread application prospect in hydraulic model tests and ship model tests．

Estimation of the ecological baseflow is a hot topic in the field of stream ecology. Considering the interannual variation of the northern stream flow and the obvious changes of the streamflow between flood seasons and non-flood seasons, this paper uses the SPSS 19 software to compare the calculated results of various hydrological methods such as the Texas method and the Tennant method with the monthly average flow from 2005 to 2014 monthly (nearly 10 years) average flow correlation analysis, that the Texas method is more suitable for the ecological base flow calculation Huangtaiqiao, followed by the Tennant method. In order to make the result more reasonable, the monthly ecological baseflow in different typical years was estimated with Texas method. Then the ecological baseflow was compared with the observed streamflow to analyze the degree of safeguard. The results indicated that the ecological baseflow degree of safeguard was 100% in Jinan section of the Xiaoqing River. The main reason is that Xiaoqing River, as the drainage channel in Jinan City, receives most upstream and some urban sewage from the upper reaches, and the water itself is relatively abundant.

Aquatic plants are an important part of natural rivers, which are of great significance to river rehabilitation management, lake remediation, and sustainable utilization of water resources. This paper summarizes the research on the velocity distribution characteristics, the resistance characteristics and the turbulent structure inside the water flow from three aspects of theoretical analysis, experimental research and numerical simulation. It also proposes the direction of future research and development in the field. It is of guiding significance for restoration of ecological functions and further study of vegetation water.

Expansive soil is a typically regional special soil with remarkable deformation characteristics variated with the change of moisture content. It has a serious destruction on the engineered practices, such as channels, roadbeds and retaining walls. Curing agent is now known to be used widely because of its good modified effect and high cost performance in the field of improving the expansive soil. In the present study, the mechanism of curing agent was analyzed, and the category of curing agent was also classified. On that basis, the comparison of modified effect for the different curing agents was studied, and then the basic analysis thought and method on improving the expansive soil was discussed.

To clarify the opposite trend of the horizontal displacement and deformation trend of the dam and the bank of the Taiping Bay Gravity Dam,this paper combines qualitative analysis and judgment with the structural features of the dam,the layout of the monitoring system,hydro -meteorology,topography and geology,solar radiation and many other conditions． The results show that the different deformation mechanisms of riverbed and bank slope dam lead to the opposite trend of deformation due to the difference in dam load characteristics and observation points arranged on the downstream side． The temperature of initial observation aggravates the deformation of the two differences．

The safety detection of hydraulic steel gate is an important means to judge the safety degree of the operation of the steel gate, which is particularly important for the old equipment that has been running for several decades. Take the Xiaonanchuan reservoir as an example, its appearance inspection, door material and size detection, corrosion detection, weld inspection, stress detection and performance testing of the hoist are carried out. The finite element software ANSYS is used to simulate the stress state of the working steel radial gate, and the stress analysis of the working steel radial gate under the check flood level is carried out. According to the test results and simulation results, the security situation of steel arch-gate is analyzed, test conclusions and maintenance plan advice was proposed.It is also a reference for similar projects.

The successful development of a lifting triangular weir which can measure the water discharge of ditch,and can also adjust and control the depth of ditch ,is developed on the basis of the comprehensive application of fluid mechanics, mechanical engineering and information control technology is described herein. After the in-situ testing,it is demonstrated through the comparative analysis made between both the data from the automatic measurement and the manual measurement that can meet the accuracy of water level measurement;and the analysis of Luo Danming tracer test shows that the ecological ditch install lifting triangular weir, had a bettter effective ,the water region more, the flow path longer,hydraulic efficiency and effective volume ratio higher,which is propitious to adsorption nitrogen and phosphorus in water.

The model experiment and numerical simulation are used to analyze the orifice outflow,the pressure distribution,the pulsation characteristics and the flow field characteristics of the gate outlet,the flow around the flow condition,and the flow characteristics． The gate pressure distribution curve is “M”,and the water pressure on the surface is larger than the water pressure on the back surface,and is positively related to the upstream water depth． The gate facing the water surface is 90 degrees and the back water surface is 225 ° as the maximum pressure point． The 157° ～ 202°and 225° ～ 360°are negative pressure,the bottom 180 °and the back surface 270° are the minimum pressure points,and the negative pressure at the bottom of the gate is 180°． The pressure pulsation frequency 49．8 Hz axial flow pump blade frequency,time frequency of 0．3Hz by the gate bottom turbulent vortex and pressure intensity of the larger,the gate body along the upstream transmission,fluctuating pressure energy distribution frequency and amplitude decrease gradually and turbulence intensity decreases little by little．

The study of hydraulic characteristic of combined energy dissipation is of practical significance to improving the erosion and cavitation of high-speed flow． Numerical simulation is more time-efficient and cost-saving than the physical model,but it is also difficult to simulate the cavitation of stepped spillway face． This paper makes an experimental study of the change of the dimension with the same proportion of transitional step on the hydraulic characteristics of combined dissipation．The study shows that when the length of a single step and the contact area of the step with the air are different,the larger the unit cavity area is,the larger the average aeration concentration is, the more the aeration is． The overall changes in the mean pressure along the experiment program are basically the same． Increasing the size of the transition steps in the same proportion ( Scheme 3,Scheme 4) is beneficial to the dissipation of water flow energy and the reduction of high-velocity flow to the erosion of the anti-arc section． Expanding the size of the transitional step with the same ratio ( Scheme 4) can effectively reduce the risk of cavitation damage occurring to the stepped wall surface． When the size of the transitional step in the same proportion is changed,the size change of the transitional step and the WES curve should also be taken into consideration． It was not appropriate to use a step with a small size to converge with it．When the control of other variables is the same,the size of the same-scale enlarged transition step ( Scheme 4) is better than other experiment schemes

Abstract：In this work, the Yichang section of hard revetment of the Yangtze River embankment was selected as the example, the technical feasibility, construction process and restoration effect resulted from application of the BSC (Bio-Substrate Concrete) to revetment was investigated and discussed, establishing the restoration and protection system of rigid revetment slope. It is proved by engineering practice that ability against 5m/s water erosion was enhanced, restoration of native plants was easier, plant diversification to maintain the stability of ecosystems was induced more easily, plant biomass within objective area was significantly increased, free maintenance after plant system developed. Meanwhile, the organization scheme and the form of construction work suitable for urban were suggested respectively if BSC was employed for remake project.

To ensure the quality of concrete pouring, and monitor of dam concrete construction process effectively, the paper present an intelligent technology of high arch dam construction quality control, which automatically analyze, estimate, predict and early warn, through comparing the real-time monitoring and key parameters with the control index, such as vibration trajectory, vibration time, angle of the insert and insert depth, to avoid the non-standard construction phenomenon. The technology has been applied in 38 casting blocks at 300m Xi Luodu Arch Dam, with the accuracy of plane movement can be five centimeters, insertion depth can be one centimeter, vibrating time can be one second and azimuth positioning can be one degree. The application has verified the reliability and validity of this technology, which has further application values.

Water cellars are widely used in areas with no central water supply in western China, and are key structures for collecting and storing rainwater. On the basis of the original design specifications, this technology can increase the tensile strength of concrete and reduce the amount of concrete by adding wire mesh to the material of the pits. In the process of construction, the waterproof layer in the middle of the pit wall is added, which improves the seepage of the pit body, guarantees the stability of the water cellar, and increases the volume of the water cellar. Due to the reduction of the top weight of the pit and the increase of the hanging point, the roof of the pit can be hoisted, and the pit body can be mechanically excavated to reduce the construction cost. After demonstration and promotion, the majority of farmers can generally accept and use this technology, which is having a landmark effect on the construction of the water cellar.

Shaft tubular pump system has many advantages, such as straight passage, less hydraulic loss, less investment, simple structure, convenient installation and maintenance. In order to grasp the hydraulic characteristics of shaft tubular pump system to provide a preliminary basis for selecting the type of pump and inlet and outlet passage structure form, combined with shaft tubular pump system inlet and outlet flow optimization of Yancheng west sluice gate station. Through the three-dimensional turbulence calculation method, several parameters such as the profile of the outlet passage, the height, width and profile of the inlet passage are optimized, put forward the design scheme of inlet and outlet passage considering civil investment and hydraulic performance synthetically. The results of the study show that: The inlet flow pattern is significantly affected by shaft’s inner and outer profile of inlet passage. The width and height of the inlet passage are changed to improve the velocity uniformity of the inlet of the impeller and the conditions of the pump entry. The flow pattern and pressure distribution of the gradual diffusion section are improved by reducing the width of the outlet passage and canceling the straight section tube in the original design scheme. The results can provide a theoretical basis for the hydraulic design of the shaft type inlet and outlet passages and the reasonable determination of the size of the flow passage. Relevant achievements have been implemented in the project and achieved good results.