In recent years，the contribution rate of water and sediment into the middle reaches of the Yellow Ｒiver has changed significantly． According to the observed data of hydrological station in the middle reaches of the Yellow Ｒiver，the middle reaches of the Yellow Ｒiver is divided into three regions of Toudaoguai － wubao，Wubao － longmen，Longmen － tongguan． The variation of contribution rate of water and sediment entering the Yellow Ｒiver is analyzed in different periods． The results show that the runoff and sediment load in Toudaoguai Station and three regions showed a decreasing trend from 1958 to 2016 year． After 2000 year，the water contribution rate of the toudaoguai increased by 6．8%，the water contribution rate decreased by 1．9% ～ 2．5% in three regions． The contribution rate of sediment load for Toudaoguai increased by 7．4%．The contribution rate of sediment load in the up region decreased by 22．5%． The contribution rate of sand load for the middle and lower reaches increased by 5．1% and 10% respectively． There is a significant correlation between sediment transport load and runoff in the middle reach of the Yellow Ｒiver．

Aiming at the ecological environment and unique water resources situation of urban drinking water source based mainly on the reservoir type in Yunnan plateau city，this paper constructs the stress response model based on water resource vulnerability evaluation of the plateau urban drinking water source index system，a case study is made of the reservoir type water source，which is a typical representative of Qing Shui－hai source area of Xundian Area． The evaluation method of integrating is used to analyze and assesse water resource vulnerability from 2015 to 2017 in Qing Shui－hai source area of Xundian Area，the results show that the water resources vulnerability degree was moderate from 2015 to 2017，indicating current water resources of Qing Shui－hai source area of Xundian area carrying capacity，regional economy， social development and ecological environment protection exist significant malposition，water environmental protection and comprehensive renovation should be strengthened．

It is necessary for high－quality rain gauge network to acquire data on both rainfall depth and spatiotemporal variability of intensity during rain events． The estimates of the mean areal rainfall across entire catchment and sub － basins interpolated by the two rain gauge networks are compared． Ｒesults show that the difference between estimates from two rain gauge networks is depended by the spatial variability of rainfall as that the difference become outstanding along with the spatial variability of rain increases，especially in the sub－basins near by the divide． Despite the mean areal rainfall computed by two rain gauge networks are equal，the difference between the rainfalls of sub－basins obtained from them may be very remarkable． It is concluded that besides the mean areal rainfall，the interpolated results of sub－basins should be taken into account in planning and optimization of rain gauge networks and some rain gauges should be arranged nearby the basin divide． 

In order to analyze the effects of different scale storage tanks on the initial rainwater runoff and pollutants reduction, the SWMM model was used to simulate the water quality in the area of Rule lake in Nanchang city.The measured data is used to calibrate the model and verify the accuracy of the model. The results show that the model is reliable and it can be applied to the research on the control of regional rainfall non-poin source pollution.On this basis, the combined models of different scales double-storage tank under small recurrent rainfall conditions were constructed to analyze the interception effect of initial rainwater runoff and the reduction of pollutant concentration such as TSS, CODcr, TP and TN.The results show that the interception rate of runoff by the storage tank is between 12% and 22%, and the reduction rate of each pollutant is more than 50%. The flow discharge and velocity in the interception tube are positively correlated with the volume of the storage tank, and the overall trend is increasing.

SA ( Sensitivity analysis) is the most efficient way to identify important parameters in a model． In this paper，sensitive parameters of a physically based distributed hydrological model，BTOPMC，are identified by using SA methods． And the Fujikawa Basin is chosen as the research area． Firstly，MOAT ( Morris One At A Time) method is used to qualitatively analyze the sensitivity of BTOPMC model parameters under appropriate sampling design and sufficient sample size required for effective screening of sensitive parameters． According to the outputs，it has been found that there are 9～ 12 sensitivity variables in BTOPMC，and the involved parameters are Srmax( m) ，m( m) and n0 ． In addition，a quantitative method，DGSM ( Derivative － based Global Sensitivity Measures) ，is used to verify the results of qualitative analysis，and the importance of all parameters is quantified． The result of quantitative SA is basically consistent with that of qualitative SA．

For the fine description of the hydrological cycle process in the river-growing watershed, based on the distributed hydrological model EasyDHM, this article simulates the process of runoff and concentration in the Zengjiang River basin. Firstly, the sensitivity of many confluence parameters in EasyDHM model is analyzed, and then the parameters with higher sensitivity are optimized.After parameter optimization, the accuracy of hydrological simulation of the three sections is higher in the period of periodic rate and inspection period, indicating that EasyDHM model is well applied in zengjiang river basin, which can play a scientific supporting role for the management of water resources in the basin, the rational utilization of water resources and the flood forecasting in the basin.

Based on the historical long-term sequence runoff data of Guilin section of the Lijiang River, BP neural network model, multiple linear regression model and ELMAN neural network model are used to train and simulate the sample data, train the model parameters and analyze the simulation errors. In this paper, the above three long-term runoff forecasting models are used to forecast the annual, monthly and ten days’ flow of Guilin section of the Lijiang River in 2016, and establish the ensemble forecasting model by the weighted average method. Compare the ensemble forecasting results with the above three model forecasting results. The results show that the ensemble forecasting model using the weighted average method can effectively combine the advantages of the above three models and significantly improve the prediction accuracy.

Based on the China Gauge － based Precipitation Daily Analysis dataset ( CGDPA) of ground grid precipitation product，four statistical indicators and classification measures are used to evaluate and compare the rainfall monitoring capabilities of Climate Hazards group Infrared Precipitation with Station Data ( CHIＲPS) ，Climate Prediction Center Morphing technique satellite－gauge merged ( CMOＲPH－ BLD) ，Ｒemotely Sensed Information Using Artificial Neural Networks － Climate Data Ｒecord ( PEＲSIANN － CDＲ) ，Tropical Ｒainfall Measuring Mission ( TＲMM) 3B42V7 satellite data sources at different scales in different provinces． The results show that: ① The maximum monthly precipitation in Jiangxi is in June，and the rest reaches the maximum in July． TＲMM 3B42V7 has the best performance in capturing monthly precipitation in different provinces． ② Based on an analysis of precipitation and correlation coefficients，TＲMM 3B42V7 can better estimate the four seasons precipitation in 5 provinces． ③ The correlation between satellite precipitation products and CGDPA is weak in low precipitation estimation area，but strong in high precipitation area． According to the spatial distribution of the correlation coefficient and box chart，PEＲSIANN－CDＲ is suitable for Xinjiang and Jilin，while TＲMM 3B42V7 is more suitable for Shanxi，Jiangxi and Yunnan．

In order to rationally arrange wireless underground sensor networks ( WUSN) nodes in wheat field，this paper studies the transmission characteristics of 433MHz wireless underground sensor network during the four main growth periods of wheat． Besides，three－ dimensional surface of ＲSSI is built in four wheat growing periods through Matlab，whose fitting model and goodness of fit of ＲSSI are obtained，and the model verification is conducted through SPASS software． In the tillering stage experiment，the minimum of goodness of fit Ｒ2 is 0．741，the maximum is 0．927． Ｒoot mean square error is in the range of 1．518 ～ 3．372 dBm． In the jointing stage experiment，the minimum of goodness of fit Ｒ2 is 0．664，the maximum is 0．986． Ｒoot mean square error is in the range of 0．571～ 3．491 dBm． In the heading stage experiment，the minimum of goodness of fit Ｒ2 is 0．673，the maximum is 0．888，Ｒoot mean square error is in the range of 1．569～ 4．372 dBm． In the watery stage experiment，the minimum of goodness of fit Ｒ2 is 0．665，the maximum is 0．784． Ｒoot mean square error is in the range of 4． 062 ～ 4． 842 dBm． The model can better predict the received signal strength under different conditions through － the － earth communication and provide the technical support for sensor network node deployment and the establishment of the system in soil information acquisition．

In this paper, the paddy fields in the Poyang Lake basin were the research object, "Luliangyou 996" early rice was used as a test material, using multi-factor randomized block design, the dynamic change characteristics of the rice′s leaf SPAD values along with growth progression under different irrigation patterns, nitrogen application levels and topdressing methods were studied, the interaction of water-nitrogen coupling on SPAD values and yield and the relationships between SPAD values and yield in each growth stage were analyzed, and influence mechanism of irrigation, fertilization and topdressing on rice′s leaf SPAD values were expounded. The results showed that, the influence of irrigation and topdressing on SPAD values was reflected in the stage of reproductive growth, while the amount of nitrogen applied was reflected in the whole growth period. Nitrogen application can significantly increase leaf SPAD values and yield, but the contribution of nitrogen fertilizer to production showed marginal effects. The three-time fertilization method can significantly delay the decline of SPAD values and improve crop yield. The interaction between irrigation mode, nitrogen application rate and topdressing method was not significant. Improving the leaf chlorophyll content of the leaves during the grain-filling stage is an effective method to stabilize or even increase production. From the perspective of water saving and increasing yield, the optimal field management measures are W1N2F2, and the leaf SPAD values in the grain-filling stage is maintained between 37-40.

In order to improve reference crop evapotranspiration in Ningxia Yellow Ｒiver Irrigation District ( reference crop evapotranspiration，ET0 ) ，This paper simplifies the accuracy of the formula，based on the daily meteorological data of the 5 national－level basic meteorological stations in Ningxia Yellow Ｒiver Irrigation District from 1962 to 2017 by using Priestley－Taylor ( P －T) ，FAO－ 24 Ｒadiation ( FAO－24) ，and 1948 Penman respectively． Monteith ( 1948P－M) ，Hargreave－Samani ( HS) and Makkink ( MA) five simplify calculation methods to calculate the multi－year average ET0，using the Penman－Monteith ( PM) formula as the standard． The obtained daily values are linearly fitted to the five simplified calculation methods，the slope k and the empirical coefficient c are determined by the least squares method，and the fitting formula is verified by the calculated data from 2001 to 2017 by using the mean absolute error ( MAE) ． The average relative percentage error ( MＲPE) and Nash－Sutcliff coefficient ( NS) are used to evaluate the accuracy of each site in Ningxia Yellow Ｒiver Irrigation District． The results show that before the revision，the simplified calculation methods have poor applicability and accuracy for each site in Ningxia Yellow Ｒiver Irrigation District． After modification，the fitting effect and accuracy are improved to different extents． Therefore，the five simplified calculation methods have a high application prospect in Ningxia Yellow Ｒiver Irrigation District．

Ｒice planting and typical climatic areas in Yunnan Province are selected to carry out experimental research on rice crop coefficient ( Kc) and its regularity observation． On the basis of meteorological data，reference crop evapotranspiration ( ET0 ) is calculated． At the same time，water balance equation is established based on the data of water layer of the field，so as to analyze and calculate rice water requirement ( evapotranspiration，etc．) ． In this way，Kc in each typical area can be deduced and the changing rules can be studied． The results show that， the Kc value in the whole growth period of rice is between 0．99 and 1．18 in each typical region of Yunnan Province． A single peak curve with smaller initial and terminal stages and larger intermediate stages is presented． There is no obvious rule for Kc spatial difference． The humid and semi－humid climate zone is slightly larger，while the warm and cool climate zone is slightly smaller． Kc decreases with the increase in altitude，but the relationship between them is not close． The inter－annual variation of Kc in the same typical area is not significant． The results can provide an important reference and application support for ETc calculation of rice in Yunnan Province．

The arid zone in the middle part of Ningxia is focused on as the research area by using the Morlet wavelet analysis，Mann－Kendall method and climate trend coefficient method，the characteristics of precipitation on the multiple－time scale change and variability tendency and gradient of effective precipitation ( Pa ) in the growing season are analyzed by the daily precipitation data of the national standard weather station in the research area during 1954－2016． Ｒesults indicate that Pa increases from north to south in the middle part of Ningxia，with an average annual of 216 mm，accounting for 75．25% of the total precipitation，of which the maximum is 55．9 mm in August，and 70．8% of the total effective use of precipitation between July and September． In the 1960s，during the abundant period，the positive anomaly was 238．7 mm． In the 1970s，it entered the dry period，and the negative cumulative anomaly was 226．1mm． Since 2010，it has increased． Pa has 3，6 and 10 a main cycles． The effective precipitation in all regions showed a decreasing trend，the amplitude was 2．2～ 5．2 mm/( 10 a) ，and the Pa in the whole area was 3．5 mm/( 10a) ． The total precipitation in the region from April to October also showed a significant decreasing trend ( P= 0．05) ，which was 5．3 mm/( 10 a) ． Among them，the decreasing rate of precipitation in Yanchi is the smallest by 0．8mm/( 10a) ，and the largest decrease in Haiyuan is 8．8 mm/( 10 a) ．

Qaidam Basin often plays an important ecological role in Qinghai Province． So，in order to provide the basis for the rational development and utilization of saline－alkali land in Qaidam Basin，this investigation is carried out to study the saline characteristics of soil salt and its composition． The combination of Fisher statistical analysis methods and correlation analysis is used to analyze the data from 221 soil sampling sites． According to the soil salinity classification standard of Haixi Zhou，Qinghai Province during the 2nd national soil survey， the soil salinity is classified into Grade 5 for different soil salinization type and major soil salt components． The results show that the coefficient of variation of soil salt and its components ranged from 2．8% to 597．7%． The coefficient of variation of the Cl － ，K+ ，Na + ，total salt，Ca2+ and SO2－ 4 were high variation and the values were all over 100%． The coefficient of variation of pH value was lowest，the value was 2．8%． The coefficient of variation of cation exchange capacity，organic matter and HCO－ 3was moderate variation，the values ranged from 10% to 100%．There was a significant positive correlation between total salt and K+ ，Ca2+ ，Na + ，Mg2+ ，CO2－ 3 ，SO2－ 4 ，Cl － ( P ＜ 0． 01) ，respectively． There was a significant negative correlation between total salt and organic matter，cation exchange capacity，HCO－ 3，respectively． Then，the contents of total salt，K+ ，Ca2+ ，Na + ，Mg2+ ，SO2－ 4 and Cl － were enhanced，but the contents of cation exchange capacity，organic matter and HCO－ 3were reduced with the increase in soil salinization． Na + and Cl － were the dominant process during the salinization process in fine soilplain belt of Qaidam Basin，eventually becoming the chloride salt． Increasing soil organic matter is beneficial to the reduction of soil salinization，so it can be used to improve saline－alkali land by applying the organic manures in the agricultural production．

In order to clarify the effects of drip irrigation，furrow irrigation，border irrigation and other irrigation methods on the growth characteristics and water use efficiency of potatoes，in 2018，a field experiment was conducted in the Dingxi region of Gansu Province on different irrigation techniques for potatoes to explore the use of drip irrigation，ditch irrigation，and border irrigation． Under the irrigation method，the effects of different irrigation methods on the growth characteristics and water use efficiency of potato during the fertility period when the relative soil water content of farmland was 60 % to 75 %． The results showed that drip irrigation had the greatest effect on potato stems，plant heights and leaf areas． Gully irrigation method potato is less affected by factors such as leaf aging，yellow dropoff，and can make the root system take root deeper，promote the growth of potato root crown ratio，and increase the water retention and water absorption ability of the root system; Gully irrigation improved potato yield significantly，but water use efficiency was 12．4 % lower than drip irrigation． In the water resources permit area，the use of ditch irrigation can increase potato yield，and the use of drip irrigation can improve water use efficiency．

Terrace is a soil and water conservation engineering which is formed in transforming natural processes，the gravity irrigation system of rice terraces is a typical representative of agricultural sustainable development and water resources sustainable utilization． Through hackling the related research results of rice terraces gravity irrigation system，this paper has analyzed and explored the parts，main influencing factors， and management mode of the irrigation system． It serves as a guide and provides a reference for the irrigation system protection work and modern farmland water conservancy construction．

To study the temporal and spatial variation of reference crop evapotranspiration (ET0) in central Yunnan, meteorological data from nine meteorological stations in central Yunnan from 1960 to 2017 were used to calculate ET0 at each station by Penman-Monteith formula. The time-varying trend of ET0 in different regions and sites was tested by Mann-Kendall trend test and Sen slope estimation. The results show that in time, Mann-Kendall trend test and Sen slope estimation show that the seasonal variation trend of ET0 in central Yunnan is quite different. Yuanmou shows a decreasing trend in spring, summer, autumn and winter, Kunming shows an increasing trend, while other stations show an increasing and decreasing trend. At the same time, the large evapotranspiration of crops in spring determined the whole year's cropping in central Yunnan.There are stations with increasing and decreasing trends in annual change trend, among which Kunming shows a significant increase trend, while Yuanmou, Mengzi and Huaping show a significant decrease trend.and the number of sites with significant decrease is larger than that with significant increase. In space, ET0 increasing and decreasing trend sites are widely distributed in central Yunnan, among which Yuanmou in central Yunnan shows a decreasing trend and Kunming shows an increasing trend.

Under the condition of more severe contradiction between economy development and ecological protection, a method to determine the ecological protection objectives is proposed. We take the Kuitun River Basin as the research object, the ecological protection objectives of the basin are determined based on the principle of maximizing the sum of ecological and socio-economic values of water resources. The results show that the objective ecological and socio-economic water consumption rate are 47% and 53%, respectively. The research results have significant guiding value for the rational development and utilization of water resources in the Kuitun River Basin. The proposed method can solve the problem that the objectives of ecological protection are determined mainly based on human subjective factors at present, which usually results in that the objective of ecological protection is greatly influenced by human subjective factors and causes large errors. It can therefore improve the objectivity and accuracy in determining the ecological protection objective.

Based on the field survey data of the target reach of ecological regulation of the Wenjin Ｒiver in Wujiang in 2018，the ecological integrity of riparian zone，the physical and chemical status of river water and the status of heavy metal pollution in sediments were analyzed and evaluated by various methods． The evaluation results show that both water and sediments pollution of the Wenjin Ｒiver are mainly caused by external sources。The pollution degree of heavy metals results in a high ecological risk． The ecological integrity of riparian zones in different river sections show significant differences due to different degrees of human intervention． The river reach with complete riparian zone needs to be protected in the renovation project on account of the diverse geomorphological features it presents，which not only forms a good natural landscape with aquatic vegetation in the waterfront area，but also plays an important role in intercepting cross－section source pollution and purifying water quality．

To gain insight into the change law of nutrient status of typical channel reservoirs in the southwest mountainous area of China, and to look for a more resilient, reliable evaluation method for eutrophication in channel reservoirs, this paper adopts PCA (principal component analysis) in a way that helps identify key factors that control the change of nutrient status and evaluate and discuss the results on the basis of a case study in Zipingpu Reservoir in which 7 locations of the reservoir are subject to tracking and monitoring for 30 months from August 2015 to January 2018. The results suggest that, ①The algae in the water of Reservoir clearly features evolutionary changes 14% decline in the dominance of dinoflagellate means 26% rise in the dominance of chlorophyta; ②PCA finds that the main control factors related to the changes of algae and nutrient status turn out to be DO, NH3-H, TP, TN; ③In comparison to the conventional method focusing on the comprehensive trophic status, PCA is able to deliver a more reliable evaluation result marked by an increase of 0.338 in the correlation with algae density and an increase of 0.279 in the evenness index of algae. ④A formula of flash estimation for algae in the reservoir is developed by using multivariate linear regression, with errors in the formula being controlled within 45% through a 6-month test on measured value. In this case, the paper bears certain research significance to reflecting the nutrient status of reservoir in a more comprehensive, accurate and objective way.

The SWMM ( Storm water) model is a dynamic rainfall－runoff simulation computer program，which is an effective tool for single event or long－term ( continuous) simulation of runoff water quantity and water quality in urban areas． By constructing the Nanjing Qinhuai District SWMM model，this paper simulates and analyzes the water accumulation of pipe network under different rainstorm scenarios，selects two factors of submerged water depth and submerged time to divide the risk level of waterlogging，and uses ArcGIS spatial interpolation analysis tool to analyze the risk of waterlogging in the study area and establishes the visual expression of the spatial distribution of urban rainstorm waterlogging risk． The results show that the high risk value of the study area appears in the southern“Airport Ｒiver－Xiangshui Ｒiver Wei District”，the Eastern“Youth Ｒiver，AnnＲiver Wei District”，the Western Old Town“Double Pond，Tai Light Ｒoad and Ｒuijin Ｒoad Street”．

In order to study the pollution of nutrients and heavy metals in Changdang Lake，the contents of nutrients and heavy metals are determined，the spatial distribution is analyzed and the pollution is evaluated． The results show that the average values of organic matter，total phosphorus and total nitrogen are 2．47%，695 mg /kg and 995 mg /kg，according to the standard of pollution assessment． They belong to first－ level sections． The average values of Cr，Ni，Cu，Zn，As，Cd，Hg and Pb are 83．60，4．90，39．50，136．50，11．41，0．37，0．05 and 32．80 mg /kg， all of them exceed the background value of soil heavy metals in Jiangsu Province，results of geo－accumulation index show that Cu，Zn，Cd and Hg are serious pollution．In terms of spatial distribution，the nutrient values are higher and the pollution of heavy metals is more serious in the western region．

Taking the upper basin of the Minjiang Ｒiver as the research object，this paper selects the Landsat remote sensing images of the 1990s，2001，2007 and 2014 as the data sources． Combined with the relevant socio－economic data，the dynamic changes and driving forces of the landscape pattern in the upper basin of the Minjiang Ｒiver from 1990 to 2014 are analyzed． The results show that in the past 24 years， the area of forest land in the basin has been significantly reduced，and the area of grassland，unused land，construction land and water area have increased significantly，and the area of cultivated land has not changed much． The overall degree of fragmentation of the basin increased，but its uniformity index is small，indicating that the overall fragmentation of the basin landscape is not large，the rate of decline of the landscape spread index is slow，and the dominant patches in the basin has good connectivity． The landscape types of the basin are fragmented and complicated in different degrees． Among them，the fragmentation of forest land is the highest，and the proportion of grassland in the total landscape area is the dominant landscape of the basin． The complexity of construction land patches is the highest． The driving force analysis with SPSS software shows that social and economic development，population factors and climate factors are the main reasons for the change of landscape pattern of land use in the basin

Due to the vigorous development of country in economic and social construction and the increasing population，sewage discharges have also hit record highs． Improper disposal of discharged sewage will cause different levels of environmental pollution． As a kind of advanced oxidation technology，the green Fenton catalytic oxidation method can generate active groups such as hydroxyl radicals ( ·OH) with strong oxidizing ability and organic pollutants in the oxidation system． Compared with the traditional method，it has the advantages of mild conditions，fast oxidation rate and no selectivity to oxidized objects． In addition，due to the development of heterogeneous Fenton catalytic technology，the problem of the current homogeneous Fenton reaction is solved，which has become a research hotspot in the field of water treatment． In this paper，the research on heterogeneous Fenton catalyst carrier in recent years is reviewed，aiming at finding a carrier that can make Fenton catalyst play a better catalytic effect． 

Mirs Bay is a semi-enclosed bay. The reclamation project in the Bay will cause the change of the hydrodynamic environment. Based on the verification of tidal level and tidal current, the influence of reclamation project of Yantian Port on the hydrodynamic environment of Mirs Bay is analyzed from three aspects of tidal current, tidal prism and water exchange by using two-dimensional mathematical model MIKE 21 Flow Model_FM. The simulation results show that the effect of reclamation on the flow field in the bay is limited to the vicinity of the project. After the implementation of the reclamation project, the larger range of velocity reduction occurs mainly in the north side of the project. The velocity reduction ranges from 0.01m/s to 0.10m/s. The implementation of the reclamation project will lead to the reduction of tidal prism in the sea area near the project, and reduce the self-purification capacity of the water in this sea area. In addition, the implementation of the project will increase the half-exchange period of the water in the harbor area and the western Shatoujiao Sea by about 27 hours.

“Increasing price and allocating subsidy”is an agricultural water price reform mode for farmers to save water． This paper uses the evolutionary game and simulation methods to explore the phase features on farmers water－saving action and the evolutionary mechanism from water－saving to water－pumping race at village level，knows keys of farmers water－saving collective action and limitations of“increase price and allocate subsidy”agricultural water price reform mode． Finally，it suggests improving further the agricultural water－saving system from water right system，water right trading and water users＇ associations．

The development of water environment comprehensive improvement PPP projects is an important embodiment that ecological civilization construction has continuously implemented in China． Performance evaluation is the main basis of government payment for PPP projects and an important way to promote the performance of social capital． In order to build a scientific and comprehensive evaluation method and comprehensively consider the subjective and objective influence on the evaluation and accuracy of qualitative index value，this paper establishes an evaluation index system based on PSＲ theory，uses entropy weight method and analytic hierarchy process to give subjective and objective weight to the index，and combines grey clustering with fuzzy evaluation to construct the evaluation method． Finally，the applicability of the method is proved by a case study． This study provides an effective method for the performance evaluation of PPP projects in the operation period of comprehensive improvement of water environment．

In order to solve the problems of fuzziness and uncertainty in the identification of risk factors in the operation of hydropower engineering, a risk assessment model based on SPA-Cloud model was established. Firstly, this paper sorted out the main risk indicators in the operation of the project, established an index system of risk assessment consisting of 4 primary indexes（personnel, management, operating environment and project risks）and 13 secondary indexes, and used uncertain analytic hierarchy process to determine fuzzy weights interval. Then，the set pair analysis method was adopted to refine the weight interval, and using the cloud model to determine the operational risk level of the hydropower engineering. Finally，according to an actual running hydropower engineering, the feasibility and effectiveness of the model in project operation risk assessment was proved.

Daily precipitation data during 1976-2015 at 43 meteorological stations located in northeast China were used to calculation yearly and seasonal precipitation CI (Concentration Index) and SPI (Standardize Precipitation Index). This study aimed to analyze the relationship between precipitation concentration character and drought-flood events in different seasons. Results shown that yearly precipitation CI was higher than seasonal CI. CI for winter was the lowest among the four seasons. There were significant positive correlation between yearly CI and SPI at the stations located in hilly areas. This means in those areas precipitation distributed more concentration in wetting years. Seasonal CI and SPI were significantly correlated for over half stations in spring and autumn. But the relationship were not obvious in summer and winter. Those results were meaning for better understanding the precipitation distribution characters during different seasons and it’s impacts on drought and flood in northeast China.

In view of many problems in the traditional flood control emergency drilling process of large and medium－sized water conservancy projects，a virtual reality flood control drilling cloud platform is independently developed based on NFC Internet of Things． The soft system platform consists of NFC flood control drill team building device，virtual reality emergency drill system and large data self－learning system． The system integrates advanced technologies such as NFC technology，AＲ technology，Internet of things technology and cloud technology． Its core technologies include the research and development technology of NFC flood control drill team － building device，virtual reality flood control drill system，self－learning system algorithm technology of large data management，cloud collaborative path optimization decision－ making path technology of flood control emergency drill，etc． The application shows that the system solves many difficult problems effectively in traditional flood control drilling，and is worth popularizing and applying in flood control drilling of water resources and hydropower projects．

Based on the annual maximum flood peak flow sequence from 1963 to 2014 at the first station of chengbi river reservoir and dam in karst region of guangxi, this paper adopts the linear trend, man-kendall rank correlation method and morlet wavelet analysis to comprehensively analyze the trend, mutation and periodicity of the sequence, and discusses the physical causes of the sequence variation.The results show that: (1) the annual maximum flood peak flow sequence at the first station of chengbi river reservoir and dam has a decreasing trend Of 6.3078 m3 /s per year;(2) the variation mainly in the form of jumping occurred in 1979. The physical cause of the variation was that the hydrological sequence of karst basin was more sensitive to the impact of climate change.(3) the sequence had the main period of 15a and the sub period of 8a and 28a, and there was no obvious periodic rule after 1985,which may be related to sunspot activity and other factors.

In this paper, daily meteorological data from 1980 to 2017 of 20 meteorological stations in and around Ulanqab the typical region of the farming-pastoral ecotone in central Inner Mongolia were used to calculate the relative moisture index(M) to reveal the drought change trend. Based on the inverse distance weight interpolation method (IDW), anomaly and accumulated anomaly method, Mann-Kendall trend test method, partial correlation analysis method, the spatial distribution characteristics, the variation trend and the cause of drought in the crop growing season (April to September) of Ulanqab in the latest 38 years were analyzed, and Hurst index was used to analyze the trend of drought in the future. The results showed that: (1) The spatial distribution of drought in Ulanqab is became drier gradually from the southern to the northern parts, among which Liangcheng, Zhuozi and Fengzhen are wetter, and Siziwang is drier. In the past 38 years, the average value of the M in the growing season was -0.575, indicating light drought. (2) From April to September, the M increased first and then decreased. In the past 38 years, the region became slightly dry, especially in August, which showed the most significant drying trend (α=0.01). (3) Partial correlation analysis of potential evapotranspiration (ET0) and various meteorological elements showed that the wind speed impacted on ET0 significantly, followed by the relative humidity, sunshine duration and average temperature. The main factors which that enhanced the drought are the decrease of precipitation and relative humidity, followed by the increase of average temperature, while the decrease of wind speed and sunshine hours can also alleviate the aggravation of drought. Hurst index indicated that the growing season will continue to dry in this region, and August will continue to dry strongly.

Conventional operational protocol suggests that large-scale pipeline system should be initially filled with a low flow discharge equivalent to a full-pipe velocity limit of 0.3 m/s, which may be conservative and inefficient. In this research, higher filling flow discharges were considered to investigate their influences on pipeline hydraulic performance, in which two-phase flow transients and rigid body motion of the air valve float were involved. A simplified hump pipe model with an air valve installed on the top was established and lattice Boltzmann method was applied for the numerical simulation. Based on different flow discharges, the transient characteristics of flow field were analyzed, including the velocity distribution, vertical displacement of the valve float, residual air distribution, and air release velocity through the air valve. Results indicate that the induced water hammer pressure will increase with an approximate linear trend as the filling flow discharge is getting higher, while the volume fraction of residual air pocket will increase with similar parabolic growth. This investigation provides guiding significance to water conveyance projects in regard to pipeline filling.

The single-axis cyclic plus unloading test at 4 strain rate is carried out on the size of 300mm×300mm×300mm cube concrete specimen，and the relationship between the dissipation energy of concrete and the plastic strain，with the times of adding and unloading，is analyzed. The results show that the dissipation energy at the low strain rate increases first and then decreases with the number of cycles increasing，and the dissipation energy increases gradually under the high strain rate. The dissipation energy is closely related to the damage degree of the specimen， and the greater the dissipation energy， the more structural surface， and the greater the damage degree；In the whole cycle of loading and unloading process，the plastic strain increment of concrete is stable，and there is no obvious positive correlation between the dissipation energy and the loading rate. The plastic strain of concrete increases almost evenly in the whole cycle plus unloading，and it is independent with the loading rate.

The interlayer structure or multi-layer structure is a common form of slope structure. The weak interlayer or rock layer is usually of low permeability, which has a significant influence on the groundwater distribution and permeability characteristics of the slope. Based on the water mass conservation equation and the V-G model, the unsaturated seepage of the layered slope is simulated with the PVI method. The reliability of the algorithm is verified by comparing the experimental results. The site-scale simulation results show that the slope with impeding layers is easy to cause the distribution of groundwater in multiple layers. And the seepage properties and development degree of the interlayer directly affect the distribution of groundwater in the region. Specifically, the increase of the parameter α (or the decrease of n), the decrease of the permeability ratio between interlayer and adjacent rock and soil and the increase of its thickness and elevation cause more significant distribution of stratified groundwater. This study reveals a special distribution pattern of groundwater in layered slopes, which provides reference for determining the unsaturated hydraulic parameters of similar geological structures.

In view of the insufficiency of the influencing factors of mixing time on the strength properties of cemented soil，this paper combines the muddy soil foundation of a flood gate project in Dongting Lake area to discuss the influence of mixing time and other different influencing factors on the unconfined compressive strength of cement soil． The unconfined compressive strength test of indoor cement soil with different water－cement ratios，cement mixing ratios and mixing time under different curing ages is carried out by orthogonal test method， assuming four influencing factors ( water－cement ratio，cement) ． There is no mutual influence between the mixing ratio，mixing time and curing age． Then the multi－factor－affected cement soil unconfined compressive strength model is established by the product model，and the parameters of the model are identified by the optimization algorithm． The research shows that the order of importance of factors affecting the unconfined compressive strength of cement soil under different curing ages is water－cement ratio，cement mixing ratio and mixing time． The water－cement ratio and cement mixing ratio are basically parabolic with the unconfined compressive strength of cemented soil，while the mixing time and curing age are basically logarithmic with the unconfined compressive strength of cemented soil． Considering the multi－factor effect of mixing time，the calculated values of the unconfined compressive strength model of cemented soil are well fitted with the experimental data，and can be applied to the prediction of unconfined compressive strength of cement soil，which has certain effect on actual cement soil engineering．

The evaluation of the effect of the liquefaction disposal scheme of saturated sand foundation is very important. It is related to the effectiveness and economy of the liquefaction disposal scheme, and the design scheme can be optimized. There is a ground liquefaction problem in the shield tunnel of Chittagong, Bangladesh. Effective liquefaction measures must be taken to ensure the safety of the project. This paper analyzes the advantages of liquefaction disposal of gravel piles from the mechanism and proposes a reasonable liquefaction disposal plan. On the basis of qualitative analysis, the numerical analysis and evaluation of the liquefaction effect of the base gravel pile is carried out. Using the finite difference program FLAC3D, the three-dimensional dynamic calculation model of the gravel pile before and after reinforcement is established. The liquefaction disposal effect was quantitatively evaluated by the excess pore pressure ratio, the excess pore water pressure, and the anti-floating property before and after the liquefaction treatment. The research shows that the liquefaction disposal scheme of the gravel pile has obvious effects, and the seismic characteristics of all aspects are effectively improved.

Recently, machine learning methods have been widely used in hydraulic engineering. In this study, the least squares support vector machine (LSSVM) algorithm was used to establish a prediction model for the re-aeration rate of stepped spillway under various flow regimes. Particle swarm optimization (PSO) was used to optimize the parameters (the penalty parameter γ and kernel constant σ2) of the LSSVM algorithm. The prediction accuracy of the new PSO-LSSVM model was significantly improved compared with the commonly used BP model. Error analysis showed that the average absolute percentage error MAPE, root-mean-square error RMSE and square correlation coefficient R2 of PSO-LSSVM model on test set were 1.1000×10-3, 4.8996×10-4 and 9.9986×10-1, respectively. Finally, the effect of input parameters on the re-aeration rate was evaluated by means of the mean impact value method.