Water-Energy-Food Nexus is a new subject in the field of sustainable development. In order to quantitatively analyze the influence of WEF-Nexus on the supply, demand and self-sufficiency of regional water, energy and food, a water-energy-food nexus coupling simulation model is built based on the life cycle theory and statistical methods, taking into account the resource linkage. Taking Jiangsu Province as an example, the changes of resource supply and demand, self-sufficiency rate and satisfaction degree of different consumption sectors in different situations from 2013 to 2017 are simulated. The results show that: under the current trend, the self-sufficiency rate of water and food is temporarily higher than 100%, but there is a downward trend, and the self-sufficiency rate of energy is less than 90%. After the adjustment of energy production structure and consumption level, the self-sufficiency rate of energy and water resources will increase. After the adjustment of food planting structure, the self-sufficiency rate of food will increase, but the water consumption may also increase correspondingly, which is not conducive to the improvement of the self-sufficiency rate of water resources.

Accurate assessment of urban water security risks is of great significance in supporting urban managers in adjusting water use policies, arranging water use structures, developing water resources development strategies, and promoting sustainable use of water resources. Firstly, the expert's judgment language on urban water safety risk assessment indicators can be converted into hesitant fuzzy language terms by means of text free grammar and conversion functions. The hesitant fuzzy linguistic terminology is used to express the uncertain risk information such as coercion, sensitivity and adaptability of urban water resources security. Secondly, based on the basic principle of information entropy, the hesitant fuzzy language entropy value is calculated. The weight of the risk assessment index is calculated by the relative entropy value, and the expert weight is further adjusted by the expert group consensus model. The risk assessment information given by the experts is weighted and integrated into the corresponding probabilistic language combination, and the expected value of the probabilistic language combination is calculated as the urban water safety risk assessment result. Finally, taking the water safety risk comparison of three cities as an example, the risk assessment model constructed is used to comprehensively evaluate the urban water security risk, and the effectiveness of the proposed method is further verified.

Both the comprehensive evaluation model based on TOPSIS fuzzy matter-element and entropy theories and Moran's I are applied to study the comprehensive water use efficiency in the Yellow River Basin. The results show that the water use efficiency showed increasing tendency from west to east in the Yellow River Basin. Shandong and Henan are at a good level, that of Shanxi, Shaanxi, Qinghai, Inner Mongolia, Gansu and Sichuan are medium, that of Ningxia is poor. There is a positive spatial correlation of water use efficiency among provinces. The research results have provided reference for the correct understanding of water use efficiency and spatial distribution in the Yellow River Basin.

The key towns were concentrated with population distribution and rapid economic development in the Qinghai section of the Yellow River Basin. In recent years, the engineering construction is increasingly intense, and the demand for groundwater resources is urgent. In this paper, Angsiduo Ditch in the upstream tributary of the Yellow River is taken as the research area, it's subordinated to Hualong County, Haidong City, Qinghai Province. Through geological survey, hydro-geological drilling, pumping test and sample test, the groundwater-rich area is delineated. The total discharge method is used to calculate the resources of groundwater in Angsiduo Ditch, and the groundwater quality and exploitable potential are evaluated. According to our calculation, the resources of groundwater are 41 874.02 m3/d, the exploitable resources are 13 180.40 m3/d, the degree of mineralization are 0.415~0.451 g/L, the content of Sr are 0.62~0.67 mg/L, owing to the high quality and the abundant quantity of the groundwater, it can be used as the backup and emergency water source for the towns and key projects in the area, which is tremendous. In addition, the evaluation idea can provide a reference for the evaluation of groundwater resources in other tributaries of the Yellow River.

In order to better improve the reliability and applicability of external data and enrich the data sources available in areas where basic data are scarce. The Yining, Nilek and Zhaosu stations in the western Tianshan region are taken as typical representative stations. Then, the statistical downscaling model is established based on measured precipitation data and NCEP/NCAR reanalysis data by using a series of methods such as artificial neural network(ANN), extreme learning machine(ELM), long and short term memory neural network(LSTM), support vector machine(SVM), combined simple average(CSAM) and combined support vector machine(CSVM). Finally, the applicability of different downscaling methods of precipitation downscaling are evaluated. The results show that: ① Due to the multiplicity of precipitation influencing factors and the difference of precipitation at measured stations, there are some differences in the advantages and disadvantages of different downscaling methods. What's more, the optimal downscaling method of the calibration period may not correspond to the optimal downscaling method of the validation period. ②The greater the precipitation of the measured site, the better the downscaling effect. The more uneven the precipitation during the year, the worse the downscaling effect. ③ Because the occurrence of snowfall events in winter affects the effect of downscaling, the more the overall snowfall, the worse the effect of downscaling. ④ The frequent occurrence of extreme precipitation events affects the effect of downscaling and reduces the reliability and accuracy of downscaling results. Generally speaking, the ELM, LSTM and CSVM models in the study area have certain advantages, among which the CSVM combination model has the best simulation effect on seasonal and annual precipitation, and the ELM model has the best simulation effect on the monthly precipitation distribution.

Based on SRTM v4 DEM data and hydrological analysis extension module in ArcGIS10.5 platform, the river information in the central part of the Western Tianshan Mountains is extracted. This paper uses the Basin tool to extract the boundary of the study area, fit the river density-catchment area curve through the river network density and catchment area data, then the area is determined when the river network density change rate is equal to the catchment value change rate. The perfect catchment area is 0.544 9 km2. The river network is extracted through the water collection threshold, superimposed on Google and imported into Google Earth Pro, and the differences between the extracted river network and the real river network are compared. The results show that the river network agrees with the actual river network well in this study area, and the extracted river network can be used as input data for subsequent researches.

From the three levels of water resources system, water ecological environment system and social economic system, a system of water resources protection evaluation is constructed based on water quantity, water quality, water ecology and water resources economy. With reference to the standard of the water conservancy modern indicator system, 16 index factors are divided into four grades: Ⅰ, Ⅱ, Ⅲ and Ⅳ according to reasonable numerical intervals. The entropy weight method and the normality cloud model based on the algorithmic called X conditional cloud generator are used to establish an evaluation model for water resources protection evaluation. The data of five years from 2013 to 2017 are selected to comprehensively evaluate the water resources protection effect of Ankang City. The effect of water resources protection in Ankang as been improved for five consecutive years. The conclusion is consistent with actual situation in Ankang, which shows that the model is feasible and reasonable.

How to reduce the impact of bridge construction within the river management scope on flood control of rivers and ensure the safety of buildings is the focus of flood control assessment. By summarizing the problems that are easy to appear in the flood control assessment of crossing bridges，a set of structural framework suitable for the flood control assessment report of crossing bridge is proposed. In order to further characterize and quantify the key technologies of flood control assessment，the evaluation contents，indicators，requirements，methods and basis are correspondingly proposed from the aspects of flood control standards，hydrological results，river evolution，bridge layout，drowning impact，bridge safety，pier scouring，external influence and remedial measures. The technology system is applied to the flood control assessment of a bridge in the Tao River Basin. The key technical points mentioned can provide a certain technical reference for the flood control impact assessment of river crossing bridges within the river management area. At the same time，it is of great significance to guide the optimization of river bridge engineering design and the approval decision of project authorities.

Based on the monthly natural runoff data from the main control station in the Muling River, Lishuzhen Hydrological Station from 1963 to 2017, the frequency proportional method is used to calculate the frequency results of the zero-value runoff, using the 7Q10 method (most dry monthly average runoff under 90% guarantee rate, most dry monthly average runoff in the past 10 years), the non-zero second minimum value method, the frequency ranking method, and improved dynamic calculation method calculate the minimum ecological runoff in the Lishuzhen Hydrological Station. The Tennant Method is used to evaluate the above calculation results, and combined with the measured runoff data, the satisfaction of the minimum ecological runoff and the possible impacts of the upstream water conservancy project construction are analyzed. The results show that the monthly runoff distribution of the Muling River is double peak. The minimum ecological runoff processes calculated by the improved dynamic calculation method which is the recommended makes the river in the middle flow during the wet season and the good flow during the dry season, and the river habitat stability and ecological health are more favorable. Meanwhile, the satisfaction of the minimum ecological runoff in the dry season under the measured runoff data is obviously better than that in the natural runoff data, and the river habitat conditions are better in the past 10 years. P=95% in the coming year, the river runoff is less than the minimum ecological runoff in the long term. After the establishment of the Fendou Reservoir, the minimum ecological runoff of each typical month is not guaranteed, but the water shortage is relatively small. The research results are of some guiding significance for promoting the water ecological protection of Muling River Basin.

Recently, the National Meteorological Center has launched China ’s self-developed multi-source precipitation fusion product. In theory, the emergence of this product can effectively solve the problem of flood forecasting and early warning in areas where there are no monitoring stations in China. However, domestic precipitation fusion products are rarely used in this field. The data accuracy and accessibility of this products in the simulation of storm and flood process need to be further evaluated. In this paper, the basin, controlled by Houhui hydrological station, in the upper reaches of the Tuanhe river is selected as the research area. We adopted a modular spatio-temporal variable source distributed hydrological model, taking station precipitation and domestic fusion precipitation as model inputs. The domestic fusion precipitation, blending ground rainfall stations, radar, and the FY-2 meteorological satellite, is used to simulate two measured flood processes in the Houhui Basin in 2018 to evaluate the hydrological simulation effectiveness and data accuracy of domestic fusion precipitation information. The results show that domestic fusion precipitation products have a high degree of accuracy in grasping the area of precipitation, but it is underestimated to a certain extent relative to the observation data of the site, which were 13.1% and 3.4% in the two flood processes, respectively. In terms of runoff simulation, this fusion precipitation product has high accuracy, and the certainty coefficients of the two flood processes are above 0.8, which are 0.84 and 0.91, respectively. Domestic fusion aquatic products have better application prospects on the issue of flood forecasting in dataless basins. The research results can provide case support and technical reference for assessing and improving the quality of domestic fusion precipitation data.

To explore the new way to estimate the probable maximum precipitation in ungauged areas, the basin upstream of the Xiaxi Water Level Station in the Suichuan River is selected as the research area. According to satellite precipitation products including CMORPH, CHIRPS, MSWEP and TRMM 3B42V7 and daily precipitation data of rainfall stations in the basin, the accuracy of satellite precipitation data is evaluated. MSWEP and TRMM 3B42V7 data are used with better precision, 1 d PMP in the basin is calculated by the improved statistical method. The results are 311.9 and 321.7 mm, respectively. For reference, 1d PMP is also estimated through the water vapor efficiency amplification method, based on abundant hydrometeorological data, and the result is 338.3 mm. Comparing 1 d PMP estimation results of two approaches, the relative deviation is within 8%. It indicates that satellite precipitation products have a good application prospect in the PMP estimation when lack of data.

In order to solve the problems of large randomness and susceptibility to human-induced interference in the runoff of the data-free sub-basin in the main urban area of Harbin, the Intrinsic Time-scale Decomposition (ITD) algorithm is introduced into the study of the complexity of hydrological systems. The results show that the simulated runoff in the non-data sub-basin of the main urban area of Harbin shows strong nonlinear characteristics. Among them, the runoff entropy value of the Yunliang River Basin in the north is the largest, and the runoff entropy value of the Zhaolan new river basin in the south is the smallest. The entropy value of runoff complexity shows a trend from south to north and low from north to south. By comparing white noise and colored noise, the evaluation results of wavelet entropy (PE), permutation entropy (WE) and ITD-MFE show that ITD-MFE algorithm has better robustness. The research findings reveal the complexity difference and variation law of simulated runoff in the main urban area of Harbin without data, which has some guiding significance for guiding the scientific and rational use of runoff resources in the main urban area of Harbin in the future.

In order to protect the ecological environment and the health of the residents in the North, the pollution discharge coefficient method, the method of equivalent pollution load and GIS software are used to estimate the agricultural non-point source pollution. In addition, the method of dispersion standardization is used to analyze the sequence of the pollution risk, and the method of clustering analysis to divide the types of pollution. This study analyzes the characteristics of a large northern city-Tianjin. The results show that the pollution load of COD, TN and TP in Tianjin in 2017 are 91 072.15, 11 760.7 and 871.86 t respectively, and the equivalent pollution loads are 3 035.74, 11 760.70 and 8 718.68 m3 separately. Among the districts, the Baodi District, Wuqing District and Jinghai District have higher pollution loads, which are the key control areas. The spatial analysis shows the similar distribution characteristics of pollution load and pollution intensity in different pollutants, which are higher in the middle and lower in the north and south. According to the pollution risk index, the key control areas are identified as Wuqing District, Ninghe District and Jinghai District. The medium and low pollution risk areas are respectively the livestock and poultry breeding-planting sources complex-leading areas and the aquaculture-planting source complex-leading areas. By controlling the application of chemical fertilizers, improving extensive aquaculture methods, and rationally treating aquaculture wastewater are the control measures to control agricultural non-point source pollution and reduce environmental risks in Tianjin.

In recent years, the Dutch water control concept has undergone a subversive change. It has been transformed from the “water competition” that has lasted for centuries to today's “return to the river”. In the 21st century, it was implemented in the river plan and became a new water control. The Yuhe River Project consists of 34 sub-projects. The main engineering measures are divided into 9 categories. It advocates the coordinated development of water conservancy project construction and spatial planning, maximizing the flood control safety and space quality, and fully embodying the advanced Dutch water control concept and superb engineering technology. Through the background introduction of the implementation of the river plan, typical case analysis, engineering practice influences the reasons, concept connotation and specific engineering design features of the new concept, and provides a reference for the innovation of water control concept and water management strategy in China. Finally, it concludes the enlightenment of the Dutch implementation of room for the river, including the concept of water management from “contending” to “yielding”, the strategy of water management from “single” to “multiple”.

The cast-in-place vegetation concrete with a target porosity of 24%, water cement ratio of 0.32 and the coarse aggregate size of 16~26 mm is used as the research object. The sequence image of cast-in-place vegetation concrete is obtained by computer tomography (CT) scanning technology and the two-dimensional plane pore characteristics are analyzed from the mesosacle by the ImageJ software Avizo software is used to reconstruct the pore three-dimensional mesoscopic model, analyze the space structure of the pore and simulate the single-phase seepage flow. The results show that, the pore diameter and pore area are distributed in a single peak, and the pore size is relatively uniform. The pore shape is close to a perfect circle; the difference between the average value of plane porosity and the measured porosity is small. The fractal dimension measured by box counting method shows that pores have good fractal characteristics. The spatial distribution of three-dimensional pores is consistent with that of two-dimensional quantitative analysis. The pore throat size is normal distribution, indicating good connectivity between the pores. The distribution of pressure gradient and streamline are conducive to the analysis of the seepage mechanism of vegetation concrete. The results of seepage simulation and test are in good agreement, which verifies the reliability of the reconstructed 3D model.

The concentrations of total nitrogen (TN),total phosphorus (TP), and phosphate (PO3-4) in different waters of the Karst Huaxi River are measured during the high fertilization season (April) and the low fertilization season (January in the following year) respectively. The temporal and spatial distribution characteristics and influencing factors of TN, TP, and PO3-4 are discussed and the eutrophication level is evaluated in this river basin. The results show that, the concentration of nitrogen and phosphorus, in different waters, is higher in high fertilization season than the low fertilization season in the whole. The concentration of TN, TP, and PO3-4 in different waters are not remarkably affected by the point source emission (breeding enterprises) in this basin. The spatial of nitrogen and phosphorus concentrations in groundwater are obviously different. The spatial distribution of nitrogen and phosphorus is closely related to land use types, the concentration of nitrogen and phosphorus are relatively high in waters around construction land and dry land, while they were relatively low in waters around paddy fields and woodlands. The eutrophication of Songbaishan Reservoir in the water during the fertilization season is slightly lower than the middle eutrophication level (PI = 0.99, Grade Ⅱ) and the Lumaotang Reservoir during the fertilization season is the largest eutrophic reservoir which is at the heavy eutrophication level (PI = 5.12, Grade Ⅳ), and the other reservoirs are generally at the level of moderate eutrophication (PI≥1, Grade Ⅲ).

Taking Longgang River in Shenzhen, which is a typical watershed, as an object, this paper assesses the ecological risk of ammonia nitrogen and the integrity of aquatic organisms in summer and non-summer by two methods of exposure ecological risk and aquatic ecological function. The results show that the baseline values of ammonia nitrogen (CMC and CCC) in Longgang River Basin vary in different seasons, which are about 1.6 times higher in non-summer than in summer. The ecological risk quotient of ammonia-nitrogen water in the tributaries of the basin is lower than that in the main reaches, while the community structure of macrobenthos is more stable and with a better water quality and ecological conditions in the upper reaches of the basin. The evaluation results from 2015 to 2018 show that there is a significant response trend between the water ecological function and the ecological risk value of ammonia nitrogen in Longgang River Basin. The combination of the two methods can provide a more reliable basis for the evaluation of water ecological function in small urban watershed.

In order to evaluate the eutrophication status of the Jihongtan Reservoir and provide evidence of decision for reservoir operation and management, in present study, we analyzed the phytoplankton community series and density during 2003- 2018. The assessment of nutritional status according to phytoplankton showed that the reservoir was in middle nutrition state in most time and above middle nutrition state in few time. The dominant group was diatom, diatom and green algae, blue-green algae in the winter and spring, early summer, and autumn, respectively. The variation of community assemblage around years was consistent with seasonal change of temperature. thus, we speculate that temperature and sunlight were main factors for phytoplankton growth. Additionally, the water quality in central part was better than near shore regions. large intake water has a great impact on the algal community and growth in the reservoir. However, the central part was also effected by large intake water. the intake of large amount of high-quality water will also have a certain temporary dilution on the algae density. In autumn with high incidence of algae blooms , it is necessary to strictly monitor the exogenous water quality. Measures such as increasing intake water and timely moving the outlet to the center of the reservoir can appropriately appropriatelyreduce the risk of water supply.

Agricultural non-point source pollution is random, latent and widespread, and has become one of the important factors threatening the safety of drinking water resources. Based on the principle of prevention, it is necessary to explore the pollution risk of agricultural non-point source to water source. The index method is adopted to analyze the harmfulness, discharge mode, migration path of pollutants and other factors, and to carry out the grading assessment of the risk of agricultural non-point source pollution of water source. Taking the water source of Shuangfengsi Reservoir as an example, the pollution load of agricultural non-point source is calculated from the aspects of rural life, agricultural planting, livestock and poultry breeding. Combined with the characteristics of pollution discharge, the risk assessment of non-point source pollution of the reservoir is carried out. The risk prevention and control area of agricultural non-point source pollution in Shuangfengsi Reservoir is defined, and the pollution prevention and control suggestions are put forward.

Sediments in the old branch of Fuhe River were collected in 2018 and 2019. The pH, content of total nitrogen (TN), total phosphorus (TP) and organic matter (OM) were measured. The pollution level of sediments was evaluated via organic and organic nitrogen index, single factor pollution index and comprehensive pollution index. The results showed that: the average contents of TN, TP and OM in 2018 were 2.00, 1.17 and 21.62 g/kg. The average contents of TN, TP and OM in 2019 were 1.85, 0.84 and 16.25 g/kg. The organic pollution index showed that most were classified as clean level, the evaluation of organic nitrogen pollution indexes showed that 85% sediments belong to organic nitrogen pollution. The single factor indexes showed most were in severe pollution in two years. And the comprehensive pollution indexes (FF)showed sediments were polluted heavily. Summing up sediment distribution and pollution characteristics can provide a scientific basis and support for river pollution prevention and control.

A large number of dredging projects have been carried on in many regions along with the promotion of water pollution prevention and management, yet how to deal with the dredging sediments is another environment issue. This paper monitors the heavy metal elements (Hg,As,Cd,Pb,Cr,Ni,Cu and Zn) in sediments in 14 rivers in Wenruitang River Watershed in Zhejiang Province, and assesses the feasibility for resource utilization of the dredging sediment. Results show that according to Plant Soil for Greening (GJ/T340-2016), sediments in 1, 3, 1 and 9 of the rivers are conforming to Grade Ⅰ,Ⅱ, Ⅲ and Ⅳ of greed land, respectively. According to Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land (GB15618-2018), sediments in 3 of the rivers are lower than the risk screening values, while for the remaining 11 rivers are ranging between risk screening values and risk intervention values. According to Soil Environmental Quality Risk Control Standard for Soil Contamination of Development Land (GB36600-2018), sediments in only 1 of the rivers are ranging between the risk screening values of Grade I and Grade Ⅱ, while the remaining 13 rivers are lower than the risk screening values of Grade Ⅰ. In general, the dredging sediments in the rivers in study area are appropriate for Grade Ⅳ of green land, as well as Grade Ⅱ of development land.

Due to the poor flow patterns such as backflow and vortex in the inlet passage of the pumping station, it may affect the stability and efficiency of pump operations. The Zhanghuabang Rainwater Pumping Station is taken as the research object. CFD software is used to simulate the flow pattern of the inlet flow-passage for investigating the hydraulic characteristics of the inlet flow-passage. The research results show that the design scheme without rectification measures may produce a large range of backflows and bias currents, which will bring great hidden dangers to the safety and stability of pumps. By adjusting the position of the water inlet and increasing the length and the height of the diversion pier, the main flow can be fully diffused, the flow rate, the backflow and bias current are significantly reduced. The lateral velocity deviation value is basically controlled within the allowable range. At the same time, through calculating the turbulent kinetic energy and turbulent energy dissipation rate, it explained that the optimization scheme can effectively dissipate the water flow.

Water resource is an important support for national and regional economic development and social progress. Stable and high-quality water resources are very important for the development of cities. Beijing-Tianjin-Hebei region, as a typical urban dense area, has a very prominent water resource problem. In this paper, based on the concept of circular economy, starting from the four dimensions of water supply, water consumption, drainage and recycling, a comprehensive evaluation index system of Beijing-Tianjin-Hebei urban agglomeration water resource recycling economy is established. The application of entropy way to determine the index weight, obstacle degree evaluation model is used to diagnose its obstacle factors, and ArcGIS is finally used for spatial visualization analysis. The results show that industrial wastewater discharge, length of drainage pipes and per capita daily domestic water consumption are the leading obstacles to the efficient recycling of water resources in the Beijing-Tianjin-Hebei urban agglomeration. Among them, the obstacles in Beijing are mainly the discharge of industrial wastewater discharge and the length of drainage pipes while Tianjin is mainly affected by the total amount of water supply and the amount of new water. The main obstacles in Hebei are the discharge of industrial wastewater, the length of drainage pipes, the amount of reclaimed water and the saving of water consumption.

As a kind of general fluid machinery, centrifugal pump undertakes the task of fluid transportation and energy conversion. In order to obtain a centrifugal pump with double volute with excellent hydraulic performance, the design of volute is also a part that cannot be ignored. In this paper, the main design parameters of the volute are selected in the hydraulic design process, and multiple groups of orthogonal tables are established. The influence of the main design parameters of the double volute on the performance of the whole pump is studied through numerical calculation. The numerical results show that the throat area should be selected according to the high efficiency area of the impeller so that the highest efficiency point of the impeller matches the lowest loss point of the volute, while increasing the volute base circle diameter and tongue angle can increase the hydraulic efficiency by about 0.76% and 0.16%, and reducing the thickness of the vane can increase by about 0.42%. Overall, the optimized hydraulic efficiency of the double volute centrifugal pump can be increased by about 1.7%.

According to the formation condition and hydraulic characteristics of constant gradient flow in open channel, the velocity and flow rate of open channel are calculated by iterative method based on the theory of cross section specific energy. Through practical application, in addition to river irrigation area of the flow of the water depth data and the measured data of big data computation, the upstream and downstream water depth corresponding to different hydraulic gradient and flow rate, the roughness is put forward according to the depth and time partition value. On the basis of drawing constant gradient of open channel flow Q ~ Hs~ΔH curve, this paper analyses the time in the practical engineering, the influence of the side wall of the conditions on the roughness coefficient. The method has sufficient theoretical basis, reasonable roughness value and high flow precision, and the research findings can provide a reference for the innovation and application of water measurement technology in irrigated areas.

In order to explore the spatial characteristics of soil salt, two sub-districts with different soil properties in the south bank irrigation area of the Yellow River in Ordos were chosen. The relationship between soil surface salinity and soil physical parameters was analyzed by using classical statistics and geo-statistics methods. The conductivity of 0~20 cm soil in both irrigation areas can be fitted with a semi-variance function using a Gaussian model. In sandy sub-district, the soil electrical conductivity is positively correlated with clay content, bulk density, moisture content, thermal conductivity and heat capacity, the correlation range is about 2～6 km. On the other hand, the soil electrical conductivity is negatively correlated with sand content, and the correlation range is about 2.5～4 km. In sandy loam sub-districts, the spatial correlation between soil electrical conductivity and physical properties is relatively low.

In order to analyze the flow characteristics in the saddle zone of the shaft tubular pump unit, a numerical simulation of the internal flow field is performed by Fluent on a typical tubular pump unit. The results show that the pump unit is reasonably designed and runs smoothly at the design flow rate. There is a saddle zone in the range of 54% to 63% of the design flow rate. The blade surface static pressure distribution is uniform under the design conditions, from 1.0 Q to 0.54 Q. The high-pressure area on the blade surface diffuses from the blade inlet edge to the entire outer edge of the blade. As the flow rate decreases, the backflow gradually appears inside the pump. Large-scale vortices and backflow appears near the back of the wheel and the back of the blade near the rim; backflow occurs in the inlet flow channel at a small flow rate, and the velocity loop in the inlet flow channel outlet increases continuously as the flow rate decreases. This value changes abruptly in the saddle area.

In order to evaluate agricultural water use efficiency scientifically, the evaluation index system of agricultural water use is constructed from four aspects such as water use, water saving, planting structure and water use efficiency. According to the evaluation level and standard, the evaluation model of agricultural water use efficiency is established based on the cloud model. Entropy weight method is used to determine the weight objectively, the membership degree of each indicator is obtained by X condition Cloud Generator, and weighted average method is used to obtain the comprehensive evaluation grade. According to the data of Anhui Province from 2010 to 2017, the comprehensive evaluation level of agricultural water use efficiency was lower than the middle level from 2010 to 2013, exceeding the middle level in 2014, and reaching the peak in 2017. The overall evaluation grade shows an upward trend, which is consistent with the actual situation. It shows that the model is feasible.

Drought is a complicated natural disaster. It is of great significance for the prevention and control of drought, water resources planning and management to understand the evolution of drought events. According to the monthly standardized precipitation index of 5 meteorological stations in Yulin from 1960 to 2016, the drought duration and drought severity variables are extracted by Unconnected Drought Runs (UDR) and Connected Drought Runs (CDR) methods. The Copula function is used to analyze the joint probability and return period of drought duration and drought severity. The conclusions are as follows: ①Compared with the UDR method, the data extracted by the CDR method contains more extreme data, which helps reduce the tail fitting error between the optimal theoretical distribution and the measured data；②The optimal joint distribution of drought duration and drought severity is: Suide Station is Frank Copula, Yuyang Station and Hengshan Station are Gumbel Copula, Shenmu Station and Dingbian Station are Gaussian Copula. ③The joint cumulative probability of drought in Yulin increases with the increase in drought duration and drought severity. The return period increases with the increase in drought duration and drought severity in a slow then steep trend.

The ability of GRACE satellite data to retrieve terrestrial water storage changes has been verified in many large-scale areas. However, it is hard to monitor changes in medium-scale basins due to its coarse spatial resolution. Based on the remote sensing soil moisture, by introducing a conversion coefficient Kpm, terrestrial water storage changes of flood and non-flood seasons in medium-scale basins are calculated in this study, and water balance equation is used to validate them. The results show that the correlation coefficients of dSm/dt and P-Q-ET based on soil moisture in all medium-scale basins are more than 0.7, showing a significant correlation, indicating that soil moisture can capture seasonal terrestrial water storage changes in the watershed. The correlation coefficient and the root mean square deviation are larger in the southern region, which shows that although the method has a stronger ability to capture changes in the humid region, it has a weaker grasp of the magnitude, and shows a reverse trend in the northern dry regions. The new method provides an effective way to calculate terrestrial water storage changes. Meanwhile, the calculation of medium-scale water storage changes plays a guiding role for regional water resources scheduling and management.

In order to improve the poor flow pattern of the forebay, this paper takes the side-intake of bifurcated pumping station as the object of our research. The influence of the position of the sill and the geometric parameters on the improvement of the flow state of the forebay is analyzed based on commercial software CFD. The results show that: without rectification measures, the flow pattern in the bifurcated side-intake is disordered, the water inlet conditions are poor, and the velocity distribution is uneven. By adding a sill, the water intake conditions are poor, and the velocity distribution is uneven. The flow pattern and the flow velocity distribution uniformity in the forebay can be obviously improved. In the background of the forebay with the side-intake of bifurcated pumping station, when the distance from the sill to suction sump is 2 D, the height is 0.67 D, and the width is 0.44 D, the reflow zone at the bottom of the forebay basically disappeared, and the flow pattern and velocity distribution of the suction sump was improved effectively.

Considering the complex flow measurement process of traditional open channel flowmeter and the inability to accurately obtain the required flow velocity, a multi-channel open channel flow measurement system based on ARM is designed. The system combines the pitot tube principle with the differential pressure sensor, arranges the dense measuring points in the vertical line in the open channel section, converts the sensor data of each measuring point into the flow velocity during the flow measurement, and obtains the section velocity distribution curve by curve fitting, and then uses the formula. The flow rate is further calculated. The hardware system is equipped with a real-time operating system and GUI, and the parameters and curve fitting results are displayed on the LCD screen in real time, and can also be automatically uploaded to the cloud platform. The experiment results show that the system can truly reflect the flow velocity distribution of the flow measurement section, which improves the accuracy of the open channel flow measurement, and the system has a strong human-computer interaction function, which has improved flow measurement efficiency.

The water level immediately upstream the gate of long-distance water diversion project is affected by many hydraulic control factors, and its fluctuation trend has strong non-linear and stochastic characteristics, making it difficult to simulate with high accuracy by hydrodynamic mechanism models, which remains a challenge to the diversion scheme. A new method of water level immediately upstream the gate prediction is proposed in this study based on deep learning network, and a three-layer LSTM water level prediction model is established and applied to water level immediately upstream the gate prediction which is compared with the deep neural network (DNN) in Jingshi section of MRP. The results show that the proposed model predict the trend of water level fluctuation better than DNN with high accuracy of Nash coefficient up to 0.99 and root mean square error up to 0.029 m. In conclusion, the influence of iterations on the calculation efficiency and the influence of the number of LSTM hidden units and the learning rate on accuracy should be considered in construction of LSTM model. Important reference can be provided for water level prediction, scheduling warning, water resource scheduling decision and intelligent gate control in long-distance water diversion project.

After the completion of the South-to-North Water Diversion Project, the operation management is faced with many complex risk factors. Based on fuzzy Vlsekriterijumska Optimizacija I Kompromisno Resenje(VIKOR)-failure mode and effects analysis(FMEA), a safety risk analysis model for South-to-North Water Diversion Operation Management is constructed. First, the expert team uses linguistic variables to evaluate the severity of each failure mode (S), frequency of occurrence (O), and difficulty of detection (D) in the FMEA. Then, the fuzzy analytic hierarchy process and the maximal deviation approach are used to construct risk factor weight. The risk factor weight analysis matrix integrates the subjective and objective weights to obtain the comprehensive weights of the risk factors. Secondly, VIKOR is introduced to improve the traditional FMEA model and is used to calculate the risk priority number. The case study results show that untimely flood control and irregular maintenance are the greatest risks in safety operation management. Finally, it is compared with the traditional FMEA method, which verifies the feasibility and effectiveness of the proposed method, which provides a reference algorithm for the risk analysis of operation management for the South-to-North Water Diversion Project.

The destruction of residual soil structure may result in engineering accidents, so it is necessary to study the influence of soil structure on mechanical properties. The simple shear tests and consolidated undrained triaxial tests are performed on the intact and reconstituted soil of the Western Australian residual soil in order to study the influence of the soil structure on the shear strength of the Western Australian residual soil. The test results show that in the simple shear tests the shear stress increases with the vertical stress in the same shear strain for both intact and reconstituted soil. Because of the strong soil structure, the intact soil needs larger shear stress than the reconstituted soil to produce the same shear strain under low vertical stress. While under high vertical stress, the soil structure of the intact soil is destroyed to a certain degree, the intact soil needs smaller shear stress than the reconstituted soil to produce the same shear strain. In consolidated undrained triaxial tests, when under low confining pressure the shear stress of the intact soil is larger than that of the reconstituted soil for the same axial strain due to the strong structure of the intact soil. While under high confining pressure, the structure of

Rural drinking water project is an important guarantee for the safety of water use for the majority of villagers. After a long-term construction of rural drinking water projects, the safety of drinking water has been basically solved. At present, the most prominent problems are the shortage of water resources in dry seasons and the difficulty of operation and maintenance of the existing projects. Based on the field investigation of Lufeng County in Yunnan mountainous area, and on the basis of summarizing the status and characteristics of drinking water projects in the mountainous area, this paper puts forward the system design mode of drinking water projects with “mixed water supply” in water shortage area and “graded water supply” in the area with large elevation difference, so as to provide feasible suggestions for the consolidation and improvement of drinking water safety in the mountainous area.

Under the background of “strengthening the weak points and strengthening the supervision”, the concept of administrative supervision of engineering quality has been further strengthened. Therefore, it is significant to innovate supervision methods of water conservancy projects and explore risk management and control of construction quality for improving supervision level. Numerous and high-risk earth-rock dams are taken as the research object. With the research idea of “risk events-data analysis-risk factors”, analysis of typical earth-rock dam accident cases with statistical analysis is adopted to comprehensively identify the quality risk factors from the perspective of government supervision. Then, expert investigation and factor analysis are adopted to supplement, improve and merge quality risk factors, and form risk index system of different stages from the dynamic perspective of supervision. Furthermore, the grey cluster evaluation model is used to construct the quality risk evaluation method of the earth-rock dam. Finally, the proposed method is introduced into the actual supervision and inspection, and a case study of the CFRD project is carried out. The result shows the risk level of construction quality measured by this method is consistent with the actual condition. Therefore, the method can realize the scientific quantification of supervision and inspection opinions of earth-rock dam projects and the effective evaluation of construction quality risk. It can provide decision-making reference for the supervision agencies to systematically evaluate the quality risk level of construction projects under construction and adopt differential supervision.

Water conservancy projects generally have the characteristics of a large project area, complicated terrain and geological conditions, so it is very difficult to apply BIM technology. The 3D geological model is an important basis and foundation for engineering model design and accuracy should meet the requirements of the corresponding survey stage. According to the survey data，this paper creates a BIM model by BIM collaboration platform to achieve multi-professional collaborative design. While introducing the establishment of 3D geological model by BIM software of platform A, this paper studies the advanced application technology（solid excavation, 3D sectioning，3D rendering，etc）to show the geological structure intuitively and clearly，and provide a reference for project design and information management.

Soil material is widely used in infrastructure construction, and water content is an important parameter index of soil material. In the process of earth-rock dam filling, concrete mixing, foundation pit backfilling, it is necessary to accurately and quickly detect moisture content of soil. Considering the problems of slow detection speed and long time consumption of traditional drying method, a rapid detection method of soil based on microwave humidity method is proposed. According to the plan, the Hydro-Probe IV microwave humidity sensor produced by British Hydronix company is selected as the main detection equipment, and a quasi-static spiral soil sample compactness control device is developed and used together with it. The non-cohesive soil filling materials on the site of Altas Water Conservancy Project are taken to be tested in 10 calibration samples and 15 test samples. Linear fitting and “quadratic” fitting are respectively adopted to fit the test data of the calibration samples to obtain calibration curves. The maximum error between the moisture content test results of each component of the two calibration curves and the real value is less than 0.7%. The accuracy and reliability of the test results are also studied by error analysis, correlation analysis and significance analysis. The results show that the moisture content of non-cohesive soil based on microwave humidity method has high reliability, and the research results have been well applied in the construction of Altas Water Conservancy Project.

Empirical mode decomposition has lately received great attention due to its excellent adaptability. However, the end effect problem has made it challenging to the performance of the signal decomposition and distorts the results. Existing suppression algorithms are limited by continuation accuracy or computational efficiency. In order to quickly add extreme points which are more in line with the internal information and endpoint characteristics, an unconventional end effect processing method on the basis of echo state network(ESN) extension technique coupled with Hidden Markov Model (HMM) is proposed. Firstly, the initial sequence is predicted by the ESN network with less complexity and simple training but high precision. Then the error sequence is modeled and estimated by the classical statistical method HMM. Finally, the preliminary prediction value is combined with the estimation error to obtain the corrected extension sequence. The simulation and experiment results demonstrate that the ESN-HMM can effectively extract the time-varying characteristics of signal amplitude and frequency. It makes the EMD decomposition result more exact and provides a prerequisite for the signal processing and fault diagnosis of rotating machinery.

Smooth Particle Hydrodynamics (SPH) and Lattice Boltzmann Method (LBM) can accurately capture the violent deformation of free surface as novel numerical simulation methods. SPH and LBM methods are applied to simulate the 2-D dam-break flow, the 3-D dam-break flow striking fixed and transportable obstacles. Compared with previous flume data, SPH method can get smoother and clearer free surface, but some particles adhere to the boundary wall and the predicted pressure values fluctuate at times. The viscous term of momentum equation and boundary conditions need to be improved further. Coupled with the discrete element method (DEM), SPH method can resolve solid-fluid interactions. The free surface obtained by LBM method is splashing and broken at large deformation, and the prediction of water depth and pressure is more precise, but the simulation of rigid body motion needs to be strengthened. In addition, the computational efficiency of the two methods is also compared. Under the same CPU scenario, the computational efficiency of LBM is higher than that of SPH method. GPU parallelism can greatly reduce computing time.

Hydro-turbine regulating system is a complex nonlinear system, and its operating conditions often change greatly. After a hydropower unit is connected to the grid, a set of PID control parameters is generally used, while it is hard to ensure a good dynamic quality under different operating conditions by using fixed control parameters. At this time, it is necessary to optimize the control parameters of the unit under different operating conditions so that the control performance of the governor meets the desired requirements. Based on the biogeography-based optimization, the PID parameters of a hydropower unit under certain operating conditions are optimized and compared with that obtained by other algorithms. The results show that the optimal PID parameters obtained by the new algorithm have better control quality, which is of great significance to the optimal operation of the unit.

Rainfall is an important factor leading to slope collapse and instability. Therefore, it is of great practical significance to optimize the rainfall factor function when the statistical regression model of slope deformation is established. In this paper, based on the fact that the rainfall factor function in the statistical regression model ignores the influence of rainfall time on the deformation of rock slope, the undetermined exponential function is proposed to replace the rainfall component function of single rainfall attenuation coefficient. Three kinds of rainfall models are applied to the deformation monitoring data of the tensile crack body on the right bank slope of a power station. The analysis shows that the fitting of the improved rainfall model to the previous rainfall is more consistent with the actual condition, and the multiple correlation coefficient of each measuring point of the improved rainfall model is higher than that of the traditional rainfall model. The prediction accuracy of this model is high.