This study evaluates the accuracy of ECMWF ensemble precipitation forecast information in accumulated utilization form and in daily utilization form based on the observed area precipitation of basin upstream of the Nierji Reservoir. Five indicators, i.e., correlation coefficient (R), relative bias (RE), root mean square error (RMSE), availability rate within one class (RU) and availability rate considering safety (RS) are applied for the evaluation and the lead time of the precipitation forecast is from 1 day to 10 days. Results show that ① when the forecasting data in accumulated utilization form is applied, the forecasting precipitation data from lead time of 1 day to 10 days all have high correlation with observed data, their relative biases are within allowable error range, the predicted precipitation of level I to level IV have relatively high availability rates, and accuracy meets the requirements for inflow forecast or reservoir operation; ② when the forecasting data are applied in everyday utilization form, the forecasting data whose lead time within 5 days meet the accuracy requirements and are suitable for inflow forecast or reservoir operation, while the forecasting data whose lead time beyond 5 days have low correlation with observed data, high relative biases, relatively low availability in level Ⅲ and level Ⅳ forecasting precipitation, and are not recommended for direct use.

The urban residential areas in Chengdu City are selected as the study area. The SWMM (Storm Water Management Model) is used to simulate the runoff process when the study area encounters design storm with different return period under current situation and LID(Low Impact Development) applied situation. The results are then analyzed to estimate the reduction effects of sponge city based LID measures on urban storm flood. The results show that: ① the combined LID measures have more significant effects than any single LID measure in reducing total runoff and peak flow．In single LID measure programs, the Biological Retention Pool has more significant effects than the green roof and the grassed swale in runoff control. ② LID measures can effectively reduce urban storm flood, and relief the urban waterlogging in the original drainage system.

Water resource is the key factor maintaining a harmonious social, economic and ecological development in inland river basin. In this paper, the GRACE and global land assimilation data system (GLDAS) are used to analyze the temporal and spatial distribution of terrestrial water storage in the Tarim River Basin, and the terrestrial water storage estimated by GRACE is downscaled based on GLDAS. The results show that the terrestrial water storage decreases with a rate of 1.6±1.1 mm/a during 2002-2015 in TRB, and the terrestrial water storage in the northern part of the basin were deficit, and that in the south of the basin is surplus. Meanwhile, the liner correlation coefficient (R2) between GRACE and GLDAS is 0.35(P<0.05), while the liner correlation coefficient (R2) is 0.99 (P<0.001) between downscaled terrestrial water storage and the original. Although the runoff from the mountain in the Tarim River Basin is increasing, the drought satiation in the Tarim River Basin is still severe. Furthermore, the changes of terrestrial water storage is impacted deeply by the snow cover and 0 ℃ in the summer and dominated by groundwater resources in TRB.

Because of the characteristics of low mountains, little streamlet, concentrated precipitation, poor water cut condition and small capacity of storage in the island area, most of the precipitation flows into the sea before it can be used. Therefore, the lack of water resources in the island area becomes the main restrictive factor for the development of island. Based on the topographical and hydrological characteristics of sea islands, this project establishes a comprehensive utilization system of Island rain-flood integrating assessment, hysteresis and collection, storage, scheduling and utilization through theoretical analysis and experimental research. Fujian Pingtan Island is take as an example for the application of the system.

Dam safety not only affects the flood control, power generation, irrigation and other benefits of reservoirs, but also affects the lives and property of the people. The simulation of reservoir collapse floods can provide important technical support for reservoir flood control risk management, disaster assessment, and disaster relief. Taking the Qinghe reservoir as an example, the DAMBRK model is used to calculate flood flow during the gradual dam failure. The high resolution DEM digital elevation model is used to extract the grid topographic data of the study area, and then the flood evolution of the lower Qinghe River is established based on the EFDC hydrodynamic module. The dynamic model simulates flood risk factors such as submerged water depth and inundation range, and serves as a technical basis for the flood control and disaster reduction decision-making in the lower reaches of Qinghe Reservoir.

Scholars have carried out lots of studies on water rights, but research on water rights trading on rural pools and evaluation of the tradable water quantity is just beginning. On the basis of summarizing the current methods of determining the tradable water quantity, a new method is proposed to consider the utilization potential of rural pools. The water utilization potential is calculated by virtual water user strategy. Three methods are used to analyze the tradable water quantity for two pools located in Lin'an. The results show that the lower the guarantee probability, the greater the utilization potential. The method which regards the increased value as tradable water use right quantity evaluates the least amount. The new proposed method derives a more reasonable amount of tradable water use right. These evaluation methods can provide technical support for water rights trading on rural pools.

The runoff process of Panlong River Basin is simulated based on SWAT( soil and water assessment tool) ，and the model is droved by using different land use data of 1994,2000 and 2008 to evaluate quantitatively the influence of land use change on the process of runoff production in Panlong River Basin. The results show that ①from 1994 to 2008, the influence of the area of forest agricultural land was reduced，the area of construction land, grassland, water area and bare land area was increased，the lateral flow and base flow per unit area in Panlong River Basin was decreased by 7.08 and 4.25 mm respectively. The surface runoff，actual evaporation and potential evapotranspiration were increased by 13.69，2.51 and 2.20 mm，respectively. The total runoff was increased by 2.36 mm．② Compared with actual evaporation, potential evaporation and total runoff, the former is more sensitive to land use change in rainy seasons, while the latter is in dry seasons.

In this paper, physical model tests are carried out to study the effects of floods on the impact characteristics of buildings under different pre-burst water depth and distance from the building to the break. The comparison and analysis by the data are made from four aspects: the change of water level, the change of dynamic pressure, the law of peak pressure distribution, and the relationship between water level and pressure change. The results show that ①There are differences in the form of peak and the trend of variety of loads on the upstream surface of buildings. ②The pressure at the measuring point increases with the increase in upstream water inflow. ③The load on the lower side of the center of the upstream face of a building is the largest. ④The water level of the central line is in agreement with the pressure change at the lower measuring point of the building. In view of the difference of pressure characteristics at different points on the upstream surface of buildings, a general pressure map of vulnerable point on the upstream surface is drawn, which can be used to guide the design of houses in potential areas threatened by mountain torrents and to verify the relevant empirical formulas.

To solve the problem of SWMM model with many parameters and hard to calibration, Morris method is promoted to deal with global sensitivity analysis, select sensitive parameters and calibrate sensitive parameters based on MATLAB genetic algorithm. The results of the case study show that the genetic algorithm can effectively complete the process of rate setting. After rate setting, the values of each parameter are the maximum permeability rate 50.25, the minimum permeability rate 12.61, the manning coefficient 0.018 2 in the pipeline, and the manning coefficient 0.008 7 in the impermeable area. The method can be applied to the process of parameter calibration and can give a set of parameters with the field measure results which can improve the accuracy and stability of simulation.

The assessment of county water environmental carrying capacity is one of the objectives of China's water pollution prevention and control action plan. It is an important basis for regional water environment differentiation, scientific management and emission permit allocation technology. Taking Changxing County, Zhejiang Province located in the southwestern bank of Taihu Lake as an example, based on the results of the division of water ecological function zones, an index system of water environmental carrying capacity is constructed, which consists of 14 indexes, including water resources, water environment, water ecology and land ecological function. The weight of each index is determined, and then the vector model method is used to divide the zones. The comprehensive evaluation of water environment carrying state is carried out. The results show that the water environmental carrying capacity in Changxing County is in the middle-lower level on the whole, with obvious regional differences. The carrying capacity values of D1 and D4 zones are 0.062 and 0.029, respectively. Water resources index and land ecological function index are better overall, while water environment and water ecological index are worse overall. The research shows that the main factors that restrict the water environmental carrying capacity in Changxing County are river ecological degradation, water quality of water functional areas not up to the standard, point and non-point source pollution, etc. It is also the key to improve the water environmental carrying capacity in Changxing County.

In the arid region of Northwest China, human activities affect and change the groundwater circulation mode under natural conditions through a large-scale water conservancy project and agricultural diversion irrigation, which lead to a series of secondary disasters. Taking Bayin River in Delingha City, Qinghai Province as an example, the alluvial plumes and the alluvial plain were selected as the study area. Two-dimensional numerical model of groundwater flow was established along the river with MODFLOW software to divide the groundwater flow System to analyze the effect of river bed hardening on the groundwater circulation mode under the same runoff. The results show that the hardening of the river bed changes the recharge mechanism of the groundwater to the river and greatly affects the local groundwater flow system. As a result, the groundwater level drops overall, the position of the overflow zone moves backward, and the groundwater excretes in a concentrated way.

In accordance with zero-dimensional river water quality model, a complete system for health assessment which includes river morphology, hydrology, environment, habitat factors and characteristics of human activities is established by considering the integrity and connotation of river, and the healthy evaluation of river is put forward based on the model of set pair analysis and extension theory. Finally, an empirical research on the health status of Huanghe River in 2017 is carried out. The result shows that Huanghe River is in a state sub-health at present, which is consistent with the reality. It is urgent to take a number of comprehensive measures for water system connection, pollution prevention and control, ecological restoration and water conservation, so that the river gradually restores vitality.

Based on remote sensing image data, topographic data and small-scale survey data, the soil erosion prediction model combined with the general soil loss equation and the three-factors method is used to classify the soil erosion modulus of the forest land in Shicheng County and establish a low-quality and benefit forest evaluation system. Spatial distribution and land use characteristics studies are conducted. The results show that low-quality and benefit forests in inferior site conditions are mainly distributed in the northeast and southeast of the study area, accounting for 31.48% of the forest area in the entire study area. The proportion of slight erosion in the study area is the largest, which is close to 93% of the total area. In addition, the erosion area of severe erosion is 5.56 km2, which accounts for 0.351% of the total area of the entire study area. In terms of total soil erosion, the contribution rate of sparse forest land with 2.92% erosion area to the total erosion amount in the study area has reached 4.80%, and the total erosion amount is almost twice the proportion of the erosion area. The results aim to enrich the identification theory of low-quality and benefit forests, and provide a scientific basis for low-efficiency forest transformation.

Eutrophication of lakes is one of the most serious water-pollution problems in China. Much attention has been paid to ecological restoration as a way to reduce its impact on the environment. Research on the effect of ecological restoration on spatial and temporal variations of water nutrient can provide some important scientific evidence for the management of lake water quality. We conducted an investigation in Changhu Lake of Hubei Province where a series of ecological restoration projects including the “removal of aquaculture enclosure”, the “Planting aquatic plants”, and the “fishery stock enhancement” are implemented. According to the water quality monitoring data of four sampling spots from 2014 to 2018, spatiotemporal series analysis was adopted to analyze its variation characteristics, including total nitrogen (TN), ammonia nitrogen (NH+4-N), total phosphorus (TP), and chemical oxygen demand (COD). The results showed that in terms of temporal distribution, the annual and seasonal variations of water nutrients in Changhu Lake was obvious. Water nutrients showed a gradual decline trend from 2014 to 2018. Nutrient concentrations were high in January and July, while low in May. The spatial pattern of water quality showed a gradual improvement trend from Miaohu zone to Haizihu zone, Mahongtai zone, and Yuanxinhu zone. Water quality of Changhu Lake was improved after ecological restoration.. However, due to the wastewater discharged by non-point sources including livestock and farming from Changhu Lake basin, the situation is not optimistic. In order to recover the self-purification of water bodies and make the water environment in Changhu Lake favorable to people's production and life, we should control the non-point pollution from Changhu Lake basin effectively.

The variation characteristics of CODMn, NH3, TP and TN of eight monitoring sites in Meiliang Bay and Dongtaihu Bay are analyzed between 2014 and 2018. The results show that, TP concentration of Meiliang Bay of 2018 stayed the same as that of 2014, but TP concentration of Dongtaihu Bay increased. TP concentration is significantly negative correlation with SD in Dongtaihu Bay. Submerged macrophyte coverage has decreased sharply since 2015, leading to the reduction in transparency, which is one of the main reasons for the TP concentration increase in recent years. It is suggested that recovery the submerged macrophyte coverage to 2014 level is one of the most important ways to further improve the water quality of Dongtaihu Bay.

In order to study the velocity distribution in curved river of backwater conditions, flume experiments with different backwater degrees are carried out in 90° curved rivers. After a detailed measurement and analysis of the three-dimensional flow velocity in the bend by ADVP, it is found that the hydrodynamic axes of different backwater degrees are basically the same before the bend top section, the position of the hydrodynamic axes shifting to the concave bank is closer to the downstream with the increase in backwater after the top section. As for the same section, with the increase in backwater, the water depth and the average velocity decreases gradually, the distribution of longitudinal velocity and transverse velocity becomes more uniform.

This paper calculates the cost-effectiveness of the watershed in terms of water and soil conservation benefits，ecological benefits，economic benefits，social benefits，and land opportunity costs by reference to the criteria such as soil and water conservation in 2015. It comprehensively uses the market price method and comparative analysis method to evaluate the benefit of water conservation in the upper reaches of the Ganjiang River. The total benefit of water conservation measures in the upper reaches of the Ganjiang River in 2015 is 910.7 million RMB，that ecological benefits>economic benefits>social benefits>water conservation and soil conservation benefits； 648.4，377.8，87.6，46.8 million RMB，respectively； land opportunity cost is 249.9 million RMB in 2015； the higher the proportion of non-production land in the land before conversion to forest land，the greater the NPV value，the more economically efficient. The water conservation measures in the upper reaches of the Ganjiang River have obvious effects on ecological benefits and economic benefits，and play an important role in environmental protection and economic growth in the region.

In recent years, the frequent occurrence of Limnoperna fortunei in water transfer projects affects the project operation and water quality safety. Based on the investigation of growth characteristics and hazards of Limnoperna fortunei, the advantages, disadvantages and applicable situations of physical, chemical and biological control methods are summarized. In addition, two new control methods under engineering conditions are introduced. It turns out that the physical method is the simplest but less practical for projects. The effect of chemical method is the most obvious. However, the by-products have potential risks to water quality safety. The biological method has the highest ecological benefits, while it takes a long time to have an effect. Multi-stage segmental prevention and centralized regional control under engineering conditions have taken into account the control effect and environmental benefits, given full play to the advantages of a single method, and reduced or even eliminated the weaknesses of a single method by integrating and superposing methods, which serves as references for the next step to explore scientific, effective, economical and ecological methods.

In this experiment, winter wheat, the main grain crop in China, is selected as the research object to find the best irrigation depth through water regulation. The test uses PVC pipe farming, soil column experiments have five water depth treatments: the surface irrigation (T1), 40% of the water depth of root system distribution (T2), 60% (T3), 75% (T4), 90% (T5), during the reproductive period, a total of five times irrigation, respectively for the winter, spring, jointing, heading and filling water (winter are ground water irrigation, and the rest is deep irrigation). Through the study period of winter wheat under different fertility in the process of plant height, leaf area index, root-shoot ratio and the final yield and water use efficiency indicators, such as analysis under the T4, winter wheat yield and water use efficiency, the largest as the experiment under the condition of optimal irrigation scheme, provide a theoretical reference for the development of water-saving agriculture production.

In order to study the hydraulic performance of improved bidirectional drip irrigation emitter and the influence of its structural parameters on the hydraulic performance, the orthogonal experimental design method is adopted, and 6 structural parameters of emitter are taken as factors, to form 25 groups of schemes, and hydraulic performance tests are carried out under 5 different pressures ranging from 0.05~0.25 MPa. The results show that the flow index of 25 schemes is 0.401~0.498, and the minimum flow at 0.10 MPa is 1.50 L/h, which has good hydraulic performance and relatively small flow. The results of range analysis show that the angle α between the water retaining device and the upper wall of flow channel has the greatest influence on the flow index, and there is a positive correlation; Using regression analysis, the regression model between 6 structural parameters and the flow index is established, and the results show that the correlation is good; The experimental verification shows that the regression model can accurately predict the flow index. This realizes the improved bidirectional flow channel parametric design, and has a certain theoretical reference for its structure optimization.

In order to explore the reasonable nitrogen application time sequence on saline-alkali soil and improve the efficiency of water-regulated nitrogen application, nine groups of two-dimensional soil water infiltration experiments are conducted under the influence of different nitrogen application time series. The results show that the water content of single point source decreases as the horizontal direction advances and the vertical direction deepens, and the water content is the highest below the emitter (0, 0 cm); the water content of intersection point will form a cohesive surface in the profile (due to the early intersection of two single point sources). The conductivity of single point source increases with the advance of horizontal and vertical direction of wetting front, and the maximum value of conductivity appears at the farthest wetting front. The effect of conductivity washing at intersection point is better than that at single point source only from surface soil. Under single point source, the water content in the profile (0~30 cm in horizontal direction and 0~30 cm in vertical depth) is the largest, which is 1.45% higher than the average water content under W condition, while the conductivity of N-W-N and N-W is 1.26% and -0.34% higher respectively, and the conductivity of N-W-N, N-W-N-W and N-W time series is 392.15，177.57, 389.30 μS/cm less than the initial value. The average moisture content of N-W-N-W sequence is 0.57% higher than that of W sequence at the intersection point, while that of N-W-N and N-W sequence is - 0.68% and - 2.26%, respectively. The conductivity of N-W-N, N-W-N-W and N -W decreases 688.32, 142.50 and 565.97 μS/cm compared with the initial value. It is concluded that the water holding capacity and salt washing effect of N-W-W-N, N-W-N, N-W time series are better than those of the other five time series. The research results serve as a reference for the implementation of water and fertilizer integration.

The specialization of drip irrigational equipment (DIE) means that DIE's functions or features can meet any requirement of drip irrigation field. In accordance with the phenomenon that DIE produced by some of Chinese factories does not have enough technical parameters or product varieties, so that engineers are difficult to design or manage drip irrigation system (DIS), and its special property is not embodied enough in market of drip irrigation techniques, the functions and technical parameters of DIE supplied by the factories are analyzed in this paper, based on engineers' requirements for DIE features in the design or management of the DIS as well as specific plants' requirement for DIS in supplying field micrometeorological environment to the plants. It is believed that factories' unsystematic comprehension to their DIE results the DIE in imperfect performance in specialization. Therefore it is profitable to DIE's specialization that the factories design or develop their DIE functions on the basis of requirements of every DIE consumer and the relevance of each DIE in DIS operation. The effort of this study is helpful for one to correctly understand the specialized development of the DIE.

This paper uses Tumochuan to analyze the surface total radiation (Rs) and surface net radiation (Rn) by using meteorological data such as daily sunshine hours, temperature, and relative humidity from 1978 to 2017 to calculate daily Rs through six sunshine duration models. Then the calculation results of the models are checked with measured data of Rs from 1987 to 1991 to determine the best calculation model suitable for the region, and daily Rn is estimated through radiation calculation formula of Penman-Monteith recommended by FAO in 1990. The time variation features of Rn over 40 years are analyzed through linear trend analysis and Mann-Kendall trend analysis. The analysis results show that: ①The overall fitting precision of Bahel model based on sunshine hours is the best, demonstrating the best applicability for the region. ②The Rn of Tumochuan plain shows an upward trend in the first half of the year and a downward trend in the second half of the year. And the Rn through four seasons is written as summer > spring > autumn > winter. ③Over 40 years, the average Rn of summer has a prominent upward trend while Rn of spring, autumn and winter show a downward trend, among which Rn of winter has the most significant decline and Rn of autumn has the faintest droop.

With mathematical statistics, principal causes analysis and multiple linear regression analysis, in this paper,it has comprehensively analyzed the response of grain crops yields on the climatic change, farmland under effective irrigation, and fertilizer purified usage of Guangxi during 1978a to 2017a. It showed that, ①in the bivariate correlation statistics, grain cropping yield in Guangxi is positively correlated with the annual effective accumulated temperature, annual mean temperature, effective irrigated area and fertilizer purified usage; ②Four principal component factors were extracted from the main cause analysis. The component matrix load after rotation of the annual irradiation time, annual average daily-total solar radiation exposure, annual precipitation and annual mean minimum temperature, in the 1st principal component were 0.815, 0.742, -0.673 and -0.594,respectively.The annual effective accumulated temperature and the annual mean temperature were 0.980 and 0.973 respectively after rotation in the 2nd principal component.The effective irrigation area and fertilizer purified usage were 0.980 and 0.973, respectively, after rotation in the 3rd principal component.The annual mean minimum temperature and annual mean maximum temperature were 0.557 and 0.876, respectively, after rotation in the 4th principal component; ③With 4 extracted principal components,a multivariate regression model was constructed after the main cause analysis. This model can explain 50.5% of the variation in yield of grain cropping in Guangxi (P=0.041<0.05), and can be used to comprehensive analyze and predict the yield of grain cropping in Guangxi based on the change of climate factors, effective irrigation area and fertilizer usage.

The diffusion section of the front pool of the pump station is short. After the incoming flow enters the front pool, it is difficult for the water flow to spread evenly, and it is easy to form undesirable flow states such as reflux and vortex, which affect the efficiency of the pump and causes energy waste. Through hydraulic model test, the different sediment conditions, inlet flow state, flow rate distribution and siltation pattern of the front pool of “tight” lateral inlet flow of pumping station in multi-sediment river diversion project are observed. Under the same conditions, the greater the width of the front pool, the better the flow state of the water flow. When the width of the front pool is 3M, the water surface fluctuation range is -0.3~0.3 m, there is a non-through surface reflux vortex with a maximum diameter of 0.5 m. Under the same water and sediment conditions, the width of the front pool shows a positive correlation with the amount of silt. Combined with the test results, this paper puts forward the optimal shape of the “tight” lateral inlet flow of the pump station that improves the flow state of the front pool, improves the efficiency of the pumping station, and reduces the siltation, which serves as a reference for the design unit to further optimize the selection.

In order to study the pressure pulsation transient cavitation flow field inside the TZX-700 axial flow pump without rear vane deeply, this paper uses ANSYS CFX software, based on the SST turbulence model and Rayleigh-Plesset homogeneous flow cavitation model. The pressure pulsation of TZX-700 axial flow pump without rear guide vanes is studied by numerical calculation of transient pressure pulsation cavitation flow field. This paper mainly calculates the transient pressure pulsation cavitation flow field of the axial flow pump without rear guide vane under three different flow conditions (0.9Qd, 1.0Qd, 1.1Qd), and analyzes the design of the axial flow pump in the design, the time-domain and frequency-domain diagrams of the pressure fluctuations of the cavitation volume fraction on the surface of the lower impeller with the impulse rotation time and the pressure fluctuations of the transient cavitation flow at different monitoring points of the impeller inlet and outlet sections under different operating conditions. The results of numerical calculations show that the cavitation flow field of the axial flow pump without rear guide vane is generally stable under the design conditions compared with other conditions during one impeller rotation period; the impeller pressure pulsates periodically. At each monitoring point of the impeller, the pressure periodically changes with the impeller rotation time. The frequency of the periodic impulse pressure of the impeller without a rear guide vane is mainly concentrated on the impeller rotation frequency and its harmonic frequency.

Taking potato in limited irrigation areas of arid zones in central Ningxia as the research object, this paper analyzes the soil moisture, photosynthetic physiology, yield and water use efficiency of the potato under different water treatment by the irrigation experiment data for 2014-2015. Results indicate that: the growth of potato with under-mulch drip irrigation mainly uses the soil moisture of 0~60 cm soil layer, the middle and late of June and the last ten days of July to the first ten days of August to be the key period of water demand. The photosynthetic rate (Pn) and the transpiration rate (Tr) of the leaves are in a double-peak parabolic type, and the crest value is at 12∶00 and 16∶00, and 14∶00 has a minimum value. The yield and water production efficiency of the potato can be improved by reasonable supplementary irrigation, and the maximum growth rate is 53.11% and 12.88%, respectively. Comprehensive analysis, the under-mulch drip irrigation regime of potato is irrigation quota 1 050 m3/hm2, irrigation 3 times, bud growing period, tuber formation stage and tuber growth period once each.

In order to explore the effects of different irrigation quotas on the water consumption, plant growth, yield and water use efficiency of mature walnuts under drip irrigation conditions, and determine the appropriate irrigation quota, this experiment uses the walnut of 10 years old as the research object. Three kinds of irrigation quotas (375, 450, 525 m3/hm2) are set as the treatment to carry out field trial research. The results indicate that: the length of new shoots and the size of transverse and longitudinal diameter of fruit of walnut tree increase with the increase in irrigation quota, water consumption increases gradually with the development of growth period. In the hard core period and oil conversion period, the evapotranspiration of walnut reaches its peak, water consumption also reached the highest in the whole growth period, the sum of the water consumption modules of the three treatments during these two growth periods reaches 66.52%, 70.25%, and 72.00%, respectively. The Kc of walnut showed a single peak curve under different irrigation treatment, the single day ET0 of mature walnut showed parabolic characteristics from flowering and fruiting stage to oil transformation stage. Based on the comprehensive analysis of the test results, it can be concluded that the treatment with irrigation quota of 450 m3/hm2 is the best treatment, which is suitable for popularization and application in actual production irrigation.

In this study, the three-dimensional numerical simulation of the full flow channel of a high-head hydropower station turbine is used to study the internal flow characteristics of the guide vane watershed under three different conditions, and the numerical calculation results of the HLA542-LJ-275 turbine are analyzed. The results show that under three operating conditions, the area with the highest sediment concentration inside the movable guide vane appears near the head of the guide vane and a significant high-pressure area appears near the head. The area with the highest sediment velocity is located on the suction surface of the movable guide vane. The research findings have some guiding significance for the selection and design of the turbines of the high-head hydropower stations.

In the condition monitoring and fault diagnosis of hydropower units, the signal de-noising is extremely important for extracting vibration signal feature accurately, the de-noising algorithm with classic threshold function proposed by D.L Donoho based on wavelet has some effects, but there are some deficiencies. After analyzing advantages and disadvantages of signal de-noising with the classical threshold function, a wavelet de-noising algorithm with an improved threshold function is brought up in this paper. The Matlab indicates that the new method has a good de-noising effect, not only it significantly improves the signal to noise ratio(SNR), but also reduces the MSE, The actual collected data indicates that the new method can better retain the vibration message of the mutation points, and better track the original signal characteristics. In summary, the improved threshold function is more superior to the traditional classical de-noising methods.

The transient processes of pump-turbine units are violent and dangerous during the frequent transitions between many operating conditions. Investigating the flow patterns in pump-turbines is important for revealing the instability mechanism and guaranteeing the operating safety. The newly developed virtual reality (VR) technology is a powerful tool for showing flow fields because it can realize an intuitive and vivid display without blind angles. In this paper, computational fluid dynamics (CFD) technology is used to simulate the flow patterns of a pump-turbine in five typical operating conditions and the VR technology is used to investigate flow patterns. The flow characteristics in the guide-vanes, runner, and draft-tube are summarized and some unreported vortices are found, which is valuable for promoting understanding. This successful attempt proves that the VR method can make up for the shortcomings of traditional CFD post-processing in displaying flow patterns and has broad application prospects.

In view of the small storage capacity of the LAWI hydropower project, the large amount of sand coming from the reservoir, it is easy to accumulate in the river channel. The model test is used to study the method of water diversion and sediment prevention of intake. The advantages and disadvantages of water intake are put forward, and the operation mode of lateral water intake is proposed to ensure the water intake and sand prevention requirements of the water inlet of the power station. The sedimentation law and sand flushing method of the sedimentation basin are studied. The shape of the sedimentation channel of the sedimentation basin is optimized, which ensures both the smooth discharge of sediment in the sedimentation basin and the safe operation of the project.

Zero offset is the most important index evaluating the performance of fiber optic gyroscope. In order to reduce the error in dam safety monitoring caused by zero offset, this paper proposes a new way to eliminate the cumulative drift error of fiber optic gyro by using the static output signal value of accelerometer algorithm. The fiber optic gyro system is tested out of doors. According to the two calculation methods, the running track curve of the monitoring car is calculated, compared and analyzed with actual slop curve at the same time. The experimental results show that the trajectory curve drawn by the new algorithm can reflect the real situation of the object being monitored. Then, applying the new algorithm to the actual monitoring of the monkey rock dam safety monitoring and comparing the curve calculated by the new algorithm with the measured value of the water pipe settlement instrument confirms that the new algorithm can reflect the monitoring situation well and improve the measurement accuracy of fiber optic gyro system effectively.

The measured data of concrete dam deformation are often nonlinear and uncertain. In this paper, the wavelet soft threshold method is used to pre-treat the monitoring data and determine the influencing factors of deformation according to the statistical model of dam deformation. Then, a deformation prediction model is established on the basis of SVM. In order to improve the effectiveness of the model, the input of the model is dimensionalized by PCA to reduce the correlation between factors. Moreover, the IPSO algorithm is used to optimize the parameters of SVM, and a combined prediction model based on PCA-IPSO-SVM is established. The results show that the proposed method has high precision and a strong advantage in dealing with similar issues, providing a new way of thinking for concrete dam deformation forecasting.

As the height of dams for rockfill dams continues to increase, conventional dam safety monitoring methods are no longer sufficient. To this end, a quasi-distributed dam deformation monitoring technology based on MEMS accelerometer combination measurement is proposed. The specific composition and monitoring principle of the flexible inclinometer are expounded and indoor experiments are carried out. The experimental analysis shows that in the horizontal installation (2D mode), the vertical displacement measurement error is about 3%. In the vertical installation (3D mode), the flexible inclinometer is in the vertical direction within the reference ±60° confidence interval, horizontal. The displacement measurement error is about 2%. The displacement curve is corrected by cubic spline interpolation. The error caused by the measurement control point and the measuring point spacing is eliminated, and the measurement accuracy is improved. The flexible inclinometer has the advantages of high precision, large range, and ability to judge the absolute direction of displacement change, and has broad application prospects in dam deformation monitoring.

As a control project in the linear engineering, the slope stability at the bridge site is very important. Because the strong unloading cracks often develop the steep mountain, the rock slope may lead to collapses. In view of the slope stability of a very large bridge in Yunnan, China, the main structural surface features are determined by the detailed geological survey, and then the fractal dimensions of the structural surfaces are obtained by the box counting method so that the roughness coefficient of the structural surface is estimated and the shear strength parameters are obtained. In order to analyze the influence of the different structural surface coefficients and steep dumping crack inclination angles on the slope stability, several finite element models are established for analysis and calculation, and some suggestions for engineering reinforcement are given. The results show that ① the key structural planes controlling the slope stability at the bridge site are a group of steeply dipping strong unloading cracks and a group of gently dipping rock layers. ② where are great differences in the structural surface roughness in the study area, most of which are relatively rough. ③the finite element calculations reveal that the slope at the bridge site presents a typical progressive failure mode. If the front accumulation body is removed, the larger displacement area will be concentrated on the front of the steep ridge. ④ with the decrease in roughness coefficient and the increase in the steep structural surface angle, the slope failure model changes from the local failure to the overall failure. ⑤it is necessary to control the further deformation of the steep-dip structural plane to improve the stability of the slope, and accordingly, the corresponding engineering disposal measures are put forward. The results show that the slope after disposal is of good stability, and the next step of engineering construction can be carried out.

As a new supporting structure for strengthening multistage high- fill slope, pre-stressed anchor cable pile sheet wall has a remarkable effect. However, due to the complex interaction mechanism between soil and supporting structure, it has a great influence on each other. Often because of the unreasonable selection of supporting scheme or the lack of on-site displacement information monitoring, high slope engineering accidents occur frequently, which seriously endangers people's life and safety and property security. Based on the supporting engineering of Baidaopingshigou Unstable Slope in Chengguan District of Lanzhou City, this paper analyzes in detail the stress intensity of the pre-stressed anchor cable pile sheet wall in the supporting process by observing the displacement of the supporting structure, the internal force of the pile body and the monitoring value of the pre-stressed anchor cable. The analysis results show that the reinforcement effect of anchor cable pile plate wall is good in the process of high-fill slope reinforcement. After the completion of the slope support, the maximum displacement is about 10 mm, the maximum displacement change speed is 0.02 mm/d, the maximum acceleration is 0.025 mm/d2, and the sliding trend is not obvious. The positive and negative bending moment of the pile body alternates to avoid single-stage increase. Because of the negative friction of the fill behind the pile, the embedded section of the support pile is only under pressure, increasing the embedded force of the support pile. After the first tensioning, the loss of pre-stress is 15%~20%. After the second tensioning, the loss is small, which meets the requirements of the project. It can avoid the influence caused by the loss of pre-stress. After the adjustment of the pre-stress of the anchor cable and the stress of the slope soil, the cooperative work is good.

In order to draw up a plan of governance and management for groundwater overdraft in Bozhou, a reasonable amount of groundwater exploitation is developed based on groundwater province of overdraft assessment, the transient flow is developed by using the software MODFLOW based on the principle of finite difference method, which can reflect the trend of groundwater, the scheme of decreasing groundwater exploitation is also predicted, and the development of the over-exploited areas is analyzed, the prediction results show that by 2020 the decline rate of groundwater level will be reduced in groundwater overdraft, by 2030 the problem of groundwater overdraft in most areas of Bozhou will be solved, especially the groundwater levels will rebound obviously in the groundwater overdraft of Jinghe.

Targeted at the optimal problem of a pumping station in Hunan Province, this paper establishes the optimal model in an axial-flow pumping station with variable frequency and angle regulation, and uses the particle swarm optimization algorithm to solve problems. The results show that with the increase in static head, the power consumption increases gradually and the start angle increases rapidly under the same daily water withdrawal. Under the same static head, with the increase in daily water withdrawal, the power consumption increases gradually, and the starting angle increases gradually. Under the same conditions, the difference of power consumption between 3-period operation and 4-period operation is small. Considering the simplicity of operation, 3-period operation scheme is recommended. When the daily water lifting capacity is about 1.2 million m3 and the static lift is about 8.0 m, the pump station should be operated with matching high and low rotational speeds. When the static lift or the daily drainage volume is reduced, the efficiency of the pump is higher when the rotational speed of the pump is shifted to 490 r/min, and vice versa, to 730 r/min.

By using conventional reservoir operation chart, it is difficult to deal with the conflict among multiple profit-making objectives. This paper proposes a multi-objective reservoir operation chart optimization method combining simulation and optimization. Taking Jiayan Reservoir in Northwest Guizhou as an example, the upper and lower basic operation lines and the operation lines of reducing water supply (including water supply for industry, urban and agriculture) are first taken as optimization variables, and then a long series of simulated operation is carried out according to the zonal operation strategy. Finally, a multi-objective reservoir operation chart is obtained by balancing the relationship among water supply, irrigation, ecology and power generation. The results show that, compared with conventional operation chart, the maximal depth of water supply and irrigation decrease to a large extent in the optimized operation chart while ensuring the power generation almost unchanged. The water supply and ecological benefits are improved and the scheduling effect by optimal operation chart is satisfactory. The research findings can supply references for the actual operation of Jiayan Reservoir.

This paper takes a medium-speed centrifugal pump as the research object, establishes three kinds of centrifugal pump models with different placement angles of the blade outlets. Then the numerical simulation method was used to obtain the external characteristics of the centrifugal pump under different operating conditions. The research results show that there is an optimal blade outlet placement angle can make the efficiency to maximize; Changing the blade outlet placement angle under design conditions has a small effect on the pressure pulsation at the monitoring points in the impeller flow path, especially at the impeller inlet. The pressure pulsation at the same monitoring point gradually increases with the blade outlet placement angle, while the volute The pressure pulsation at the monitoring point in the flow channel has a greater impact; Under small flow conditions, the radial force of the impeller increases with the blade exit placement angle increases, but as the flow rate increases, the radial force of the impeller changes less when the blade exit placement angle is changed, at 1.4Qd is the most obvious. The research results can provide some values for the specific speed centrifugal pump to safety operation.