In order to study the law of water resources transformation in the Yimeng Mountain water and soil loss control area, which is under the influence of climate and vegetation cover, the Andi Reservoir Watershed is selected as the research object. The normalized vegetation index (NDVI) is used as an indicator to analyze the spatiotemporal changes of the vegetation cover. Distributed hydrological model SWAT is used to study the spatiotemporal evolution of hydrological elements, and analyze of surface water and groundwater conversion. The results show that, from 2000 to 2016, the NDVI of the watershed showed an increasing trend, of which NDVI increased significantly from 2007 to 2009.Spatially, 84% of the watershed area showed an increasing trend. The SWAT model has a good simulation effect. From 1990 to 2016, the average rainfall was 611.96 mm, the runoff was 225.96 mm, the surface runoff was 126.07 mm, the base flow was 72.07 mm, and the phreatic water recharge was 119.52 mm in the watershed. For the runoff, surface runoff accounts for 55%, base flow accounts for 27%, and subsurface runoff accounts for 18%. For the phreatic water recharge, the surface water contributes only about 5%, and the main recharge source is precipitation. Under the combined influence of climatic conditions and surface vegetation cover conditions, surface runoff decreased by 22% around 2006, the conversion of surface water to groundwater decreased, and the conversion of groundwater to surface water increased. The research results can provide theoretical basis and technical support for the rational development and utilization of water resources and the control of soil erosion in the Yimeng Mountain Area.

The north canal, which runs through the Beijing-Tianjin-Hebei Region, is the focus of the improvement of the Haihe River Basin during the 13th five-year plan period and will be followed by a water purification demonstration project. By monitoring the concentration of ammonia nitrogen, total phosphorus and COD in the water of the north canal city section, the spatial and temporal characteristics of water quality in the north canal city section are analyzed. By taking the river water of north canal as raw water, the experiment is carried out to study the removal efficiency of ammonia nitrogen, total phosphorus and COD in the raw water of north canal under different aquatic plants, different coverage area ratio and different hydraulic residence time. the dominant plant species - water onion is selected. The removal rate and change rule of ammonia nitrogen, total phosphorus and COD are obtained under the conditions of coverage area proportion of 25%, 50% and 67%. When the hydraulic residence time is 24 h, the removal rate of ammonia nitrogen, total phosphorus and COD in the water body of the north canal can reach 39.5%, 65.2% and 45.9% with the proportion of 25% covered area, and the hydraulic load parameters are 0.49, 0.15 and 17 mg/(L·d), respectively. The results are good and the demonstration project cost can be taken into account.

A new type of pump-gate combination gate structure is studied and designed in this paper. In order to avoid the low-order natural frequency of the new gate structure falling in the high-energy region of the flow load and thus causing resonance, a coupling model of the water body and the pump-gate combination gate structure is established by ANSYS software to analyze the dynamic characteristics of the structure, and explore the influence of factors such as the water level in upstream and downstream of the gate and the arrangement of submersible pumps on the door structure. Analytical results show that with the increase in water level and the decrease in gate opening, the natural vibration frequency of the structure decreases significantly; the first-order mode of the gate is changed from the whole vibration along the vertical direction to the bending vibration of the gate panel along the direction of water flow; the natural vibration frequency of the pump-gate combination gate structure decreases with the increase in the number of pumps installed.Besides, the water pumps should be concentrated in the middle of the door leaf to make the vibration characteristics of each part more balanced, providing basis for the design of the new pump-gate combination gate structure.

Based on flume experiments, the hydraulic parameters, the relationship among hydraulic factors and the law of resistance under 5 discharges, 3 vegetation combinations and 3 coverage densities are systematically studied. The results show that the flow pattern of the thin and sheet layer flow on the slope is generally turbulent, and the presence of vegetation enhances the turbulent intensity of the flow. The power function can be used to simulate the relationship between average velocity and discharge per width, and the fitting results are good. The mitigation effect of flexible vegetation on velocity is greater than that of rigid vegetation. The resistance of both the flexible vegetation slope and the rigid vegetation slope decreases as a power function with the increase in Reynolds number.

Two-dimensional water quality simulation is computationally intensive. How to improve the performance of water quality simulation under the condition of ensuring accuracy is a key problem that must be solved in water quality simulation. To this end, the study of water quality simulation is carried out in terms of performance and accuracy. To improve the water quality simulation performance, only the grids which are within or beside the river are selected for water quality simulation in the basin and the water quality simulation is decomposed into three steps, including water velocity increment calculation, water flow migration calculation and pollutant diffusion simulation. The parallelization algorithm for each step is designed separately to implement general purpose computation. To improve the accuracy of water quality simulation, the concept of stable flow field is introduced to simulate the produce prophase water regime in the basin. By importing a certain amount of upstream flow sequences before the simulation period to the model, the steady flow field is created. Finally, taking the upper reaches of Mudanjiang River as the experimental basin, the pollutant diffusion process is simulated by the two-year sequence data of water flow and COD concentration. It is found that general purpose computation can complete water quality simulation in a few minutes, while traditional water quality simulation takes several hours or even longer. More importantly, the method in this paper is not only fast in operation, but also has the similar accuracy with the traditional water quality simulation. It is possible to simulate the pollutant diffusion process in the basin accurately in real time.

The assessment of river habitat quality can provide an important basis for river ecological protection and restoration management. Combined with local ecology and environment, a river habitat quality assessment system is established by using hierarchical analysis method, which includes three habitats (channel habitat, bank habitat and riparian habitat). The river habitat quality of Beijing mountain section of the Yongding River is also assessed. The results show that the river habitat quality of the 30 sampling plots are good on the whole, with 8 sampling plots classified as “excellent”, 11 as “good”, and 11 as “moderate”. For different river reaches, the situation of overall river habitat quality and three habitats consistently show significant differences, ranking that Guanting to Zhuwo Reservoir > Zhuwo Dam to Luopoling Reservoir > Luopoling Reservoir to Sanjiadian Reservoir. Human activities, land use patterns, riparian vegetation structure and bank slope type have a significant influence on river habitat quality and water quality. This study can not only reflect the status of river habitat quality in Beijing mountain section after ecological water supply, but also provide a scientific basis for river ecological restoration and management.

Based on the basin river extraction methods of field measurements and large-scale topographic map, using digital GIS and DEM data extraction is more convenient and efficient. Based on 3D Analysis and Hydrologic Model of ArcGIS, the basin river DEM digital extraction is researched under the condition of mountainous terrain. The results show that the extraction of basin river is a total length of 350.05 km in the study area, especially large and medium-sized river length that deviation is only within 7.5%. Moreover, the extraction results are optimized, the accuracy influence of different grid number andthreshold value to the extraction are analyzed, and it isfound that the triple polynomial function is moresuitable for the relationship between the grid number and distance error.Hydrological information such as the river length, junction area and branch number is calculated, and mathematical function fitting is used. It is concluded that the threshold value is set to 12 000, the water extraction is most consistent with the actual effect of basin river. The digital extraction method and optimization of mountain basin river can not only provide technical support and reference for the extraction, but also offer scientific guidance for the difference analysis between the digital extraction and measured one.

In order to achieve a more scientific assessment of the water environment in the basin, a more comprehensive assessment method of gray water footprint in the basin is proposed based on the water footprint theory, to solve the problems of incomplete pollution accounting and inconsistent parameter selection principles in the previous assessment of gray water footprint in the basin. This study analyzes the gray water footprint and spatial characteristics of the river basin in 2018 from four pollution source: industry, resident life, livestock breeding and planting in the Fuzhou River Basin, and evaluates the water environment of the basin. The results show that the gray water footprint of the Fuzhou River Basin in 2018 was 2.923 billion m3, of which the industrial gray water footprint was 0.027 billion m3, the residents' pollution gray water footprint was 0.631 billion m3, the livestock breeding gray water footprint is 1.303 billion m3, and the gray water footprint of the planting industry was 0.962 billion m3. In 2018, the water pollution level of Fuzhou River Basin was 846.35%, which indicated that the surface water and pollution capacity in the basin had been completely exhausted and could not absorb the amount of pollutants produced in the purification basin every year. The results of the study quantify the gray water footprint of the basin and evaluate the current status of the water environment in the basin, which can provide a reference for the water environment management of the Fuzhou River Basin and other basin water environment assessments.

Influenced by human activities and social economic development, some rivers in Hubei Province are suffering from water shortage, water environment deterioration and water ecological degradation, which have seriously threatened the sustainable development of human life and social economy. A typical river in Hubei Province is select as the research object and the river ecological water requirement is calculated based on the velocity method and environmental flow index factors are considered. The results of the velocity method and the Tennant method are considered synthetically to determine the ecological water requirement under comprehensive conditions. The conclusion provides technical support and reference for the improvement of river ecological environment.

Take Fenhe Reservoir and upstream reach for example, Environment Water Qaulity Index(CCME WQI) method of Canadian Council of Ministers is used to evaluate water quality of Fenhe Reservoir, which selects 23 water quality monitoring items except water temperature stipulated in Table 1 of surface water environmental quality standard as water monitoring parameters. At the same time, CCME WQI is used to evaluate water quality of three sampling sites of the Fenhe Reservoir upstream reach, which selects pH, DO, NH3-N, BOD5, COD, TN, TP, petroleum, F- and volatile phenol as 10 water monitoring parameters. The comparison and analysis of CCME WQI and single factor evaluation method are carried out. The results show that the CCME WQI method considers the combination of “exceeding scope, exceeding frequency and exceeding amplitude”, and the evaluation results of CCME WQI are much closer to reality than single-factor-method. The quantification of CCME WQI also provides convenience for environmental management. However, the evaluation of standard and the items and number of water quality monitoring have a certain impact on the evaluation results of CCME WQI, which still needs to be further studied.

This paper focuses on the utilization of flood resources in the Sanhekou Reservoir which is an important regulating reservoir in the water diversion from Han River to Wei River. On the basis of the fractal theory, the Sanhekou Reservoir flood season can be accurate flood seasonality. The simulation of flood resources regulation is also analyzed. Based on the staged limit water level in the flood season, the considerations of flood resources regulation are projected by driving water flood resources optimization dispatch model by using long runoff series (1954-2008). The results of Sanhekou Reservoir flood season staging are as follows: the pre-flood season is from 06-01 to 06-30 (i.e. 1st Jun to 30th Jun) and the main flood season is from 07-01 to 09-30. The results show that by considering the limited water level by stage in reservoir operation, the water supply and power efficiency generation can be increased. At the same time, the ecological water supply in the lower reaches can be increased greatly. The fractal theory can meet the requirements of the flood staging in Sanhekou Reservoir and the results could provide an effective method for the utilization of flood resources.

Flood forecasting in ungauged basins is one of the most difficult tasks in hydrological research. In order to study the parameter transfer method of the HBV model in ungauged basins, The Tunxi catchment located in Anhui province was taken as an example. Based on the multi-objective functions, the HBV model can be simultaneously calibrated for multiple catchments. The parameters that can be used for different catchments were obtained in this case. The results indicate that parameter transfer based on the individual calibration shows larger uncertainty and unstable accuracy. Multi-basin simultaneous calibration can generally obtain parameters with strong stability, which can effectively improve the accuracy of parameter transfer and flood forecasting.

In this paper, the monthly precipitation data are from 1960 to 2014, the monthly natural runoff data are from 1956 to 2000, and the affected area data of flood and drought disasters are from 1960 to 2000 in the Huai River Basin. With the help of SPI and SSI drought index, M-K trend analysis and correlation analysis are used to explore the temporal characteristics of regional meteorological and hydrological drought, to reveal the response of hydrological drought to meteorological drought, and to analyze the relationship between drought indices and historical drought. The results show that the drought reflected by the SPI index is more severe than that by the SSI; the drought is the most frequent and the drought levels are very complicated in the 1960s; the drought frequency is low in summer and is high in autumn and winter. Besides, MK trend test shows that the trend of drought is not significant in the Huai River Basin. With the increase in the time scale, the correlation between SPI and SSI is increasing; the response time of the SSI to the SPI is 1~4 months in the adjacent stations; the response tends to be faster and more pronounced especially during the months of seasonal alternation. The drought-affected area is significantly expanding in the study area; SPI and SSI are negatively correlated with the drought-affected area, positively correlated with the flood-affected area, and the correlation with the flood-affected area is stronger.

To improve the accuracy of runoff prediction, research and propose a runoff prediction method that combines the marine predator algorithm (MPA) and the long and short-term memory (LSTM) neural network. Test MPA and particle swarm optimization (PSO) algorithms through 6 simulation functions, use MPA to optimize key parameters such as the number of neurons in the hidden layer of LSTM, training times, etc., and establish PCA based on principal component analysis (PCA) dimensionality reduction and non-dimensionality reduction processing. -MPA-LSTM and MPA-LSTM runoff prediction models, using the measured data from the Luoque Station in Yunnan Province to train and predict the PCA-MPA-LSTM and MPA-LSTM models, and the results are consistent with PCA-LSTM, LSTM, PCA-MPA-SVM, Compare the training and prediction results of MPA-SVM, PCA-MPA-BP and MPA-BP models. The results show that: 1) MPA simulation effect is better than PSO algorithm, with better optimization accuracy and global search ability. 2) The average relative errors of PCA-MPA-LSTM and MPA-LSTM models for instance fitting and prediction are 1.18%, 2.35%, 1.94%, and 1.96%, respectively. The prediction effect is better than the other 6 models and has better prediction Precision and generalization ability. 3) Using MPA to optimize the key parameters of LSTM can effectively improve the generalization ability and prediction accuracy of LSTM; the prediction accuracy of the data dimensionality reduction model is better than that of the corresponding non-dimensionality reduction model, and the data dimensionality reduction processing can effectively improve the prediction effect of the model.

Aiming to investigate the hydrological response of LID (low impact development) construction for a typical urban river in semi-arid region, this paper applies the rainstorm flood management model (SWMM) and one-dimensional river water balance model to simulate the rainfall runoff process under different return periods and typical rainfall conditions. Taking the Bahe River Basin at the northern foot of Qinling Mountains as an example, this paper analyzes the variation of flood peak, flood volume, river water volume, flow velocity and the possible impact on water quality and environment after different LID measures. By comparing the simulation results before and after the LID measures in terms of flood peak, flood volume, it is found that the design storm with the return period less than 10 a may cause more river water volume to reduce. After the LID construction in the urban area, the underground water recharge by river in the riverside zone is reduced, and the flow velocity in the rubber dam reservoir area is slowed down. At present, when the pollutant discharge is not effectively controlled, the river water volume will be reduced after the LID construction in the urban area of the river basin, which is not conducive to the dilution and purification of pollutants in the river water body, and may lead to the aggravation of water pollution in the lower reaches of the river. This study demonstrates quantitatively the possible effects of LID construction on urban river runoff and water quality．It may help make more informed decisions on urban river flood management, especially for semiarid region.

The flood of Shuxi Flood Protection Area in Yishusi Basin has the characteristics of mountainous flood, which has the characteristics of high water level, short duration and small flood volume. The accurate calculation of dike break flood process is the key and difficult point of flood analysis in flood protection zones. In order to accurately simulate the flood process and its evolution in the reserve, a one and two-dimensional dynamic coupling hydrodynamic model has been established. The one-dimensional model was calibrated and verified by the measured flood data in 1993, 2003 and 2012.The two-dimensional model of flood protection area and Luoma Lake has been corrected and optimized by regional investigation and survey. The real-time interactive process of water flow between river channel and nature reserve has been simulated by coupling calculation, which can be used as the calculation platform of flood submergence factors. Taking Matou breach of Yihe River as an example, the flood duration of the breach is 13.2 h, the peak flow is 537 m3/s, and the flood volume is 8.33×106 m3. The velocity of flood in the protected area is fast, the flood inundated area is 107.7 km2. It is proved that the breach flood of Matou will evolve along the Baima River to the downstream. People and property could be transferred and resettled by the submerged water depth, flood path and arrival time.

Reasonable design of exploitation scheme is of great significance to the exploitation of groundwater resources and the avoidance of environmental geological problems. The study area is located in Chengde, which is a typical region along a river．Based on the clear regional hydrogeological conditions, a numerical model of groundwater flow is established. The rational well layout is calculated on the basis of the formula and mapping superposition. The optimal exploitation scheme and the exploitable resources of groundwater are obtained by combining numerical and analytical method. The results show that 29 pumping wells is along the river in 4 regions with the distance between wells of 150 m. The distance between the wells and the river is 25 m and the allowable exploitation quantity is 4.53×104 m3/d. Luan River has not only sufficient and stable groundwater supply but also a higher guarantee degree of water intake. Meanwhile, this scheme has little impact on the regional water environment.

Foreign experience of water resources management shows that the establishment of a water rights system guaranteed by the legal system on the basis of a market economy plays an active role in the efficient allocation and sustainable use of water resources. As China's water rights system is in the period of construction and perfection, it is of great practical significance to clarify the basic characteristics of each department's policy for protecting the property rights and interests of water resources as well as promoting the improvement of the policy system. This research establishes a Driving-force State-Response (DSR) analysis framework based on the sustainable development system. The 46 policy texts related to the water rights system from the first water rights transaction in 2000 to 2019 were combed, and the theme of the policy text was coded in conjunction with Nvivo's qualitative analysis software. The results show that the policy driving force of China's water rights system is marching gradually toward the construction of the basic system. The purpose of the implementation of water rights system is that the policy status needs to complement and improve the natural resource use right system. In the implementation of the water rights system, the policy response needs to increase the establishment of the agricultural water rights system.

Based on the precipitation data of meteorological stations around the source area of the Yellow River from 1961 to 2014 and the hydrological observation data of the basin above Tangnaihai, Mann Kendall Method, Spearman rank test, ordered clustering method and cumulative anomaly method are used to analyze the characteristics of precipitation runoff change in the source area, and then the response relationship of precipitation runoff is discussed by combining correlation analysis, Granger causality test and double cumulative curve method. The results show that the annual precipitation in the source area of the Yellow River shows an insignificant decrease trend, and the annual runoff shows a significant decrease trend. The minimum year of precipitation and runoff is 2002. At the 0.05 test level, there is no obvious mutation point in precipitation during the study period, and the runoff had a mutation in 1987. The correlation analysis and Granger causality test show that the response of precipitation runoff is weak. During the whole study period, precipitation is not the Granger cause of runoff change. Finally, the contribution rate of precipitation factor to runoff reduction is 6.1% and that of non-precipitation factor to runoff reduction is 93.9%. The precipitation in the source area of the Yellow River has little influence on runoff, which may be caused by human activities, industrial production and other non-precipitation factors.

The terrain of Puyang river catchment is complicated, including hill, basin and plain. Zhuji Basin, which is located in the middle of the catchment, is a densely-inhabited area and flooding is a severe issue there due to upstream flood and downstream backwater. To solve the problem, this article integrated the Xin'anjiang hydrologic model and IFMS 1D-2D hydrodynamic model together to simulate flood inundation. Xin'anjiang hydrologic model is used to simulate the rainfall-runoff process in upstream area while IFMS 1D-2D hydrodynamic model is targeted at water flow movement simulation in downstream area. The results demonstrate that hydrologic-hydrodynamic integrating model is a feasible method to describe the whole catchment flood process which is able to remedy the deficiencies of single model simulation. In addition, different flood scenarios which consider both disaster-inducing factors and flood control engineering are simulated to calculate the water depth distribution in different conditions. Through its result analysis, resonable advice for local flood management can be offered.

In order to explore the effects of different irrigation patterns on the quality of white tea and the heavy metal content in the tea garden soil, different irrigation methods (sprinkling and drip irrigation) and different soil moisture control limits (65%, 75%, and 85%) are designed. The quality indexes of white tea including water extract, free amino acids, tea polyphenols, catechins and the content of chromium, arsenic, cadmium, mercury, copper and lead in tea garden soil are observed. At the same time, projection is introduced. The water-saving irrigation model is optimized based on high quality white tea and low heavy metal residue. The results show that the effect of sprinkler irrigation on the quality of white tea is better than that of drip irrigation, and the quality of white tea with 75% water control limit is the best. However, under the same water control condition, the effect of drip irrigation on the reduction of heavy metals on the profile scale is better than that of sprinkler irrigation. The analysis results of the projection pursuit classification model show that the 65% water control limit of drip irrigation and 75% water control limit of sprinkler irrigation is the better water-saving irrigation scheme and 75% water control limit of sprinkler irrigation obtains the projection value by 1.821. Under this irrigation mode, the contents of water extracts, free amino acids, tea polyphenols, and catechins are 47.6%, 6.66%, 14.2%, and 12.5%, and the six heavy metal ions in the soil layer (20~40 cm) in the main root zone show a decreasing trend.

Considering the combined effect of cavitation and sediment wear, the SST k-ε turbulence model and ZGB cavitation model are used to numerically study the vorticity change process in an axial-flow pump to different cavitation degrees. The results show that the vorticity is mainly distributed at the rear of the blade back, the exit edge and the blade head, and the vorticity at the working surface is small. Sediment in the transmission medium, compared with water, has a more significant effect on the vorticity in the impeller and the guide vane. Low sediment concentration and small particles of sediment can improve the vortex distribution and reduce the vortex intensity in the guide vanes. The vorticity increases as the particle size grows, although not obviously. As the cavitation pressure decreases, the vorticity in the pump goes up rapidly. It shows that the particle size has little effect on the vorticity in an axial-flow pump. Sediment concentration and cavitation are the main causes of the increase in vorticity.

To solve the problems of the lack of water control and measurement facilities, low water use efficiency and irrigation guarantee ratein Nanshantaizi pumping irrigation area of Zhongwei, the integrated measurement and control gates and total channel control (TCC) system are applied as the hardware and software foundation to popularize modern irrigation system. The results of three TCC test runs indicate that the TCC controlled integrated gates can respond rapidly to the flow dynamic change in the main canal system, automatically adjust to the best working state. At the same time, the fluctuation range of water level in the canal section is controlled within 0.05 m. The analysis shows that, TCC will improve the water use efficiency and irrigation guarantee rate effectively.

In order to explore the effects of planting methods and irrigation times on waxy corn growth and yield, the three planting methods commonly used in corn production in the test area are selected [DM(full film double ridge wide and narrow row furrow sowing),C(full film double ridge equal row furrow sowing)and CK(bare field flat crop)] combined with two irrigation modes {I0[sowing time (75%~85%)θf,seedling stage-prophase of jointing (65%~75%)θf, anaphase of jointing - booting stage (70%~80%)θf, booting stage-flowering stage (70%~80%)θf] and I1[sowing time (75%~85%)θf, anaphase of jointing-booting stage (70%~80%)θf]} to explore the differences in plant height, leaf area index, grain yield and water use efficiency of waxy corn under different treatments were carried out the study. The results show that under the same irrigation conditions, full-film double-ridge furrow sowing can significantly increase the plant height, leaf area index, grain yield and water use efficiency of waxy maize; wide and narrow rows of planting has no obvious effect on plant height, but on leaf area. The index, grain yield and water use efficiency are significantly improved. Compared with two irrigations, the four irrigations have significantly improved the plant height and leaf area index of waxy corn, but not the yield and water use efficiency. Therefore, full film double ridge wide and narrow row furrow sowing are the most suitable planting mode for waxy corn growth under the conditions of this study.

Water hammer and piping vibration will be caused when the suspended pipelines are blocked up or closed. The caused water hammer pressure and vibration rate are related to the flow velocity of the water in the pipeline, the closing time of the pipeline valve and the surplus degree of the pipeline length. To study the effects of those factors on the water hammer pressure and vibration rate, model tests of suspended pipeline are carried out. In the test, the pressure of the water hammer and vibration rate of the pipeline valve are monitored. The test results show that the increase in the valve closing time and the flow velocity would increase the water hammer pressure and vibration rate of the suspended pipeline. The suspended pipeline would burst when the valve closing time is too small and the flow velocity is too large. The water hammer pressure of the pipeline increases with the increase in the surplus degree of the pipeline length, while vibration rate decreases within a certain range of the surplus degree.

The long-distance water diversion project is an important way to realize the optimal allocation of water resources, especially in the western region, it has the characteristics of large scale, high proportion of tunnels, complex geological conditions and long lines, long construction period, and many types of projects, so it is difficult to manage and control the quality of the project. Based on the water diversion project in Central Yunnan, this paper analyzes the problems and difficulties in the quality management of the long-distance water diversion project in Southwest China, studies the measures to strengthen the quality management and control, and puts forward the “1+3” supervision mode and other quality control measures, which have achieved good results and provided a useful reference for the construction and management of the long-distance water diversion project in Western China.

Shankouyan Reservoir is an extremely important source of drinking water in Pingxiang City. However, since its completion in 2012, it has experienced the manganese pollution four times, which has seriously affected regional water safety. This paper analyzes the classical monthly water quality data, and the corresponding daily rainfall, air temperature, water level over the past five years, combined with the typical emergency monitoring data of manganese pollution incidents. Results show that, the manganese pollution incidents of the reservoir surface water generally break out near the dam which comes from deep in the bottom, while a small amount of non-point source contributes through the regional rainfall-runoff. In particular, the reservoir manganese is more likely to be brought out by the low temperature, low water level and other extreme weather such as snowfall in the research area. Meanwhile, an obvious iron concentration rise, as well as the abnormal decline of dissolved oxygen often takes place during the above incident. This study can therefore provide essential scientific evidence for mitigating manganese pollution and securing drinking water in the reservoir.

The water transfer projects of the new town in northwestern China usually have the characteristics of long distance, high lift, relatively small flow, many fluctuations along the line, high water supply guarantee rate, and outdoor water hammer prevention measures should consider the impact of cold weather on the Northwest China. The water transfer project of a new town in northern Shanxi is located in the southern edge of the Maowusu Desert. The water is pumped into the inlet pool of the pressurized pumping station through the pre-buried steel pipe in the dam, and then the water is taken from the inlet pool, pressurized by the water pumps, water is transported along the right bank bed to the downstream, and climbs along the vertical contour line at 1.26 km to the top of the slope, and then transports water along the road to the water plant. The pipeline is made of steel and ductile iron. The total length of the water pipeline is 10.5 km, with many fluctuations along the pipeline and the design water head is 157.7 m. Based on the project, the key technology of selection design for long-distance high-lift and multi-fluctuation water transfer projects in the northwest region are introduced, which can be used as reference for selection design of similar water transfer projects.

Two-stage closing butterfly valve is one of the important measures of water hammer protection. In order to determine reasonable close program of two-stage closing butterfly valve, calculations are carried out for the pump-stopping water hammer process of a long pressurized pipeline system in eight different operating conditions based on the basic theory of water hammer and the method of characteristics. Specifically, the parameters, including the minimum water hammer pressure of pipeline, maximum pressure of pump outlet, reverse speed, and time of exceeding the rated speed, which are obtained from 1080 sets of close programs of two-stage closing butterfly valve under the eight different operating conditions. The results show that all the pump stopping is not the most disadvantageous operating condition. The optimal close programs of two-stage closing butterfly are different under different operating conditions, and significant differences of the feasible region of close programs of two-stage closing butterfly valve were also observed. Through a comparative analysis, this study proposes a reasonable way to determine the close program of two-stage closing butterfly valve. The method serves as a reference for the determination of close program of valve in similar projects.

In the decision-making process of equipment refurbishment, the owner of some hydropower plant often focuses on present profit and ignores the benefits of the full life cycle, and finally results in bad effort or redundant refurbishment. By taking the refurbishment of No.4 Unit distributor mechanism in a Hydropower Plant for example, the necessity of the refurbishment is analyzed from the perspectives of safety, energy efficiency cost, and policy adaptability. Besides, boundary conditions are assumed for the two alternative schemes which are equipment replacement or overhaul. Disposable investment, operation costs, maintenance costs, fault costs and decommissioning disposal costs are analyzed throughout the full life-cycle, and related costs are converted into NPV(Net Present Value). Finally, the optimal refurbishment plan is proposed.

The anti-slide stability analysis is a critical part in the design of gravity dam foundation with multi-soft interlayer. According to a high gravity dam, the research method combining limited equilibrium method with three sliding surfaces and finite element strength reduction method is adopted. Meanwhile, the anti-slide stability analysis is carried out, and the appropriate treatment measures for the dam foundation with mud interlayer are determined. The results show that compared with the limited equilibrium method with two sliding surfaces, the limited equilibrium method with three sliding can provide a more accurate and reasonable anti-sliding stability results, and is more suitable for the calculation of deep anti-sliding stability of gravity dam with soft interlayer. Among the four dam foundation treatment schemes, the anti-shear hole scheme is highly safe and reliable and has a short construction period, and low investment, and can be preferentially used as a dam foundation treatment scheme. The finite element method strength reduction method is used to calculate the deep sliding failure mode and anti-sliding stability safety factor of the dam foundation under the anti-shear hole scheme. Compared with the three-sliding surface method, the wjzhang2006@163.com。 anti-sliding stability calculation results are similar, proving the correctness of the anti-sliding stability analysis and the effectiveness of selected dam foundation treatment measure. This study provides a reference for the anti-sliding stability calculation and dam foundation treatment design of similar projects.

A novel method of fault diagnosis based on Convolutional Neural Network (CNN), Discrete Wavelet Transform (DWT) and Singular Value Decomposition (SVD) is proposed in this paper. CNN is used to extract features of shaft orbit images, DWT is used to transform the de-noised swing signal of rotating machinery and the wavelet decomposition coefficients of each branch of the signal are obtained by the transformation. The SVD input matrix is formed after single branch reconstructing of the different branch coefficients, and the singular value is extracted to obtain the feature vector. The features extracted from both methods are combined and then classified by Probabilistic Neural Network. The results show that this hybrid method can identify different operating states of hydropower units and provide an effective basis for fault diagnosis.

An in-depth analysis has been made of the distribution rules installed capacity, power generation capacity in the past three years, and dehydration length of small hydropower stations of the Fujian Province to clarify the structure of small hydropower stations in the province, studying the changes in electrical energy after ecological restoration of rural small hydropower stations in the province, and exploring the ecological compensated electricity price in different situations. Finally, a trial scheme for ecological electricity price compensation in Fujian Province is proposed to provide reference for ecological electricity price and operation management and basis for functional departments to determine ecological compensation policies.

The determination of critical slip surface is one of the key issues in slope stability analysis. To overcome the shortcomings of basic ant colony algorithm, the combining of the ant colony system (ACS) algorithm with the vector sum analysis method (VSAM) was proposed for searching the noncircular critical slip surface of a slope. The ant division mechanism and the pheromone flatness mechanism were introduced to improve the global optimization ability of the ACS. Through two typical slope examples of ACADS and a reservoir bank slope, the feasibility and accuracy of the algorithm were verified. The results show that the proposed algorithm improves the search efficiency and prevents the algorithm from falling into premature.

Reasonable closing law of the turbine is extremely important to the control of the hydraulic transient guarantee values in hydropower stations. Because of the regulation of both blades and guide vanes, the selection and optimization of the closing law of the Kaplan turbine is complex. A new joint movement mode of blades and guide vanes is proposed for Kaplan turbines through an analysis of the turbine runaway curves. That is, the blades quickly open as the guide vane quickly close in load rejection transient process. According to the numerical simulation results of an engineering example, the maximum pressure at the volute end is greatly reduced by adopting the closing law, while the maximum unit speed increases slightly, which verifies the effectiveness of the new closing law. Based on the determined blades opening mode, the nonlinear optimization model and simulated annealing algorithm are used to optimize the two-stage closing law of the guide vanes. The closing law that meets the regulating guarantee requirements is obtained. The conclusion provides reference for selecting the closing law of Kaplan turbines.