In view of the demand for emergency response to emergency response to emergency water pollution, the rapid prediction technology for transport and diffusion of contaminated groups is studied. On the basis of relevant research at home and abroad systematically, focusing on flat, inverse slope channels in the transport and diffusion of contaminants in research have been put forward along the fast calculation formula of diffusion and transport of pollutants on the slope channel based on inverse applicability in the case of channel slope, flat slope, and the calculation results and the results of HECRAS software by contrast, try to find a fast calculation method, inverse transport and diffusion of contaminants in the channel slope. The research draws the following conclusions: in the channel bottom slope for flat slope or reverse slope, the deviation was below 20% and the calculated values of the distance simulation of pollutants transport peak, simulated pollutants value and the longitudinal length of the slope channel value deviation value of around 10%, pollutant simulated and calculated values are basically the same, therefore, Shun Po transport fast calculation formula can be used to channel the pollutants in the channel, flat against the slope of pollutant transport and rapid calculation of diffusion characteristic index, this conclusion can provide scientific, efficient and powerful decision support for sudden water pollution emergency control

This study is based on three raw plants in Fuyang，which are combined with double of three species of plants． In this study，6 plant groups，the watermifoil group，the hornwort Group，the Potamogeton pectinatus group，the watermifoil-Potamogeton pectinatus Group，the watermifoil-hornwort Group and the Potamogeton pectinatus-hornwort Group are constructed． Through the Ｒestoration experiment of eutrophic water，the purification efficiency of six groups of plants is analyzed． The results show that all the 6 plant groups has good removal effects on the contaminated substances，the removal rate of ammonia nitrogen is over 95%，the removal rate of TN is over 75%，the removal rate of TP is over 47%，the removal rate of CODMn is more than 58%，the chlorophyll has some inhibitory effect． At the same time，by horizontal contrast，the plant assemblage has a better treatment effect on NH+ 4 －N，TN，TP and chlorophyll，and the treatment effect of CODMn is similar to that of the plant monomer． The AHP method is used to evaluate the combination of plant combination． The results show that the combination of the watermifoil -Potamogeton and pectinatus Group has the highest score，indicating that it has a good removal effect of pollutants in the whole process of water purification．

Ｒain Garden is one of the technical types of“Sponge City”and“LID-City”，which has the advantages of easy management，good landscape，low cost and good ecology． The selection of planting vegetation，selection of soil burden，selection of artificial packing and particle size of artificial packing are the main structural parameters，3 levels are set for 4 factors，and the theory of orthogonal design is used． The field experiments of 9 groups of experiments are simulated by artificial rainfall． The reduction rates of chemical oxygen demand，suspended matter，total phosphorus and total nitrogen are analyzed and evaluated by TOPSIS comprehensive evaluation method，range and variance． The results show that Ｒain garden has a significant effect on reducing the chemical oxygen demand，suspended matter，total phosphorus and total nitrogen，and has the most significant effect on the purification effect of the garden with the artificial packing layer，and has the weakest effect on the selection of the planting soil layer ingredients，which is the most significant in reducing the COD，the SS，the TP and the TN in the garden． The best comprehensive disposition scheme for the purification effect of rain garden is Wolfspar． The planting soil is composed of 4 parts of garden soil，3 parts of humic soil and 3 parts of sandy soil． The artificial filler is 30 cm quartz sand 20 cm zeolite，and the particle size of artificial filler is small．

Grey water footprint method was used to calculate the grey water footprint of Hunan Province in the past 2001-2015 years', and the reasons for the change were analyzed by extended STIRPAT model, so as to provide suggestions for rational utilization of water resources and water pollution control. The results show that the grey water footprint of Hunan province dropped from 69.0747 billion cubic meters in 2001 to 671946 billion cubic meters in 2015. The proportion of agricultural grey water footprint is the largest, the industrial grey water footprint is declining, but the life grey water footprint is showing a rising trend. The coefficient of urbanization level, the proportion of the second industry, the proportion of the third industry, GDP per capita, FDI and grey water footprint intensity is 0.7996, 0.6505, 0.6543, -0.8148, -0.5115 and -0.5892, respectively. There is a inverted "U" type of environmental Kuznets curve of the relationship between economic development and grey water footprint, and there is no hypothesis of "pollution paradise"

Based on the nearby sea charts and recently measured topographic maps, remote sensing maps and hydrodynamic survey data, the evolution of the seabed topography and its causes in the tidal channel of the drowned valley type Yingluo bay are analyzed, and the evolution and hydrodynamics of the tidal channal are emphasized. The stability situation is calculated. The results show that the Yingluo Bay tidal channel in recent decades to scour, deep groove and shoal development atrophy. The reasons include human activities, decrease of sediment and other factors. Research on the evolution of the tidal channel shows that the main channel in Yingluo Bay, the ebb tidal channel showed regular evolution, gate stability is relatively high.

In recent years, Gulin river water quality was becoming worse. In order to acquaintances spatial and temporal distribution characteristics of non-point source pollution and critical?source?areas (CSAs) in Gulin River Basin. Firstly, the fractal theory was used to determine the most suitable threshold of drainage area (TDA) .On?this?foundation,this paper study the migration and the pollution load of non point source pollution in the rural area of the Gulin River Basin based on SWAT model,the results show that: the most suitable threshold of drainage area is 1500ha and the basin was divided into 37 sub-watersheds;the monthly average runoff and nitrogen and phosphorus load of the model simulation evaluation index Nash coefficient was greater than 0.5, and the decision coefficient R2 was greater than 0.6, so the SWAT model has good applicability in the research area;in 2013 ,the output of TN in Gulin River Basin was 2761.72t, and the output of TP was 338.27t; the pollution load of Gulin Town, Deyue Town, Xiang Shiping accounted for a larger proportion and the ranking of the contribution rate of the pollution sources in each sub basin were all chemical fertilizer > livestock breeding > domestic?pollution,Therefore, the agricultural chemical fertilizer ,Gulin Town, Deyue Town, Xiang Shiping were the key point for the prevention and control of the non-point source pollution in the basin.

Coexisting ions may affect the formation of BrO3- during electrochemical disinfection. This experiment used the platinum electrode as anode electrolyzed the bromide-containing water. The effects on BrO3- formation with different concentrations of SO42-, Cl-, HCO3- and NO3- were took into consideration. Under neutral conditions, the increase of SO42- could inhibit the formation of BrO3-; the persulfate and peroxide single sulfate generated on the surface of Pt electrode could occupy the active sites and reduced the probability of Br- being directly or indirectly oxidized, which reduced BrO3- formation. The coexisting Cl-, HCO3- and NO3- brought more BrO3- with more concentrations. The HOCl/ClO- produced by Cl- was the main cause to promote BrO3- formation. Reduction reaction of NO3- was easy occurred on cathode, reducing the reduction probability of BrO3- in the system of non-slotted electrode could promote BrO3- generation, on the other hand, the potential risk of NO2- would take place. Under the conditions of same ionic strength(12.56mmol?kg-1), comparing the results of BrO3- generation, the NO3- promoting efficiency was obvious than coexisting Cl- and HCO3-; After 120min electrolysis, BrO3- generation with NO3- was 3.21 times and 2.69 times of Cl- and HCO3- conditions, respectively.

By doing survey research and material collection of Longganghe River Basin, the required input data of SWAT (Soil and Water Assessment Tool) watershed hydrological model are obtained. Sub-basin boundaries are delineated by usage of spatial analysis and calculation. Then simulation case is driven by meteorological input conditions such as precipitation and temperature. Basin database is constructed at the server-side where GIS resources are provided through publishing GIS services, while WebGIS platform is developed at the browser-side. Executive file is generated by compiling SWAT model source files, after which modification of input files and parameters, running and calculation of model, extraction and transmission of model results are processed by PHP (Hypertext Preprocessor). In this study, coupling of SWAT model and WebGIS platform is realized, enhancing the display effects of model input conditions and simulation results.

In order to improve the accuracy of EasyDHM model for hydrological forecast,based on hydrologic data from 2012-2014 of the Hanjiang River Basin , PSO algorithm and DDS algorithm are used to calibrate the parameters of EasyDHM model. Parameters influences on the performance and results of two algorithms are analyzed to obtain the optimum parameters of two algorithms in calibrating the EasyDHM model.Based on that,the results of parameter calibration of two algorithms using optimum parameters was compared. the results show that the two algorithms both shown good applicability in parameter calibration of EasyDHM model of this basin and based on the comparison results ,give the suggestion of selecting algorithm when carry out hydrological forecast of floods using EasyDHM model: In the case of requiring best results of calibration,suggest using DDS algorithm when the main index of the hydrological forecast is the flood volume and using PSO algorithm when the main index of hydrological forecast is the flood peak.In the case of requiring fast calculation speed ,suggest using DDS algorithm.

In consideration of the shortage of water resources in Yantai, in order to maintain more reasonable exploitation and utilization of water resources, based on building RVA model to assess the influence of hydrological regime that Yan tai Dagujia river basin build conservancy project in recent years, combinating with BP neural network, reduce the runoff to the natural state without the influnces of the water conservancy project. Firstly, the results show that the construction of water conservancy projects like reservoir cause significant changes in the natural runoff, which month flow change degree is between 0.3 and 0.7 and limit maximum and minimum average flow changes degree is between 0.3 and 0.6, belonging to medium altitude change. Secondly, the results were analyzed from the RVA model, combined with BP neural network method to establish Dagujia river basin natural runoff reduction calculation model, through the establishment of the model reduction of Dagujia river basin natural runoff calculation, combined with the measured values to error comparison，found that the BP neural network is feasible，reliable and convenient. It is good for the water resources and hydrology engineering construction and provides a scientific basis for reasonable development and utilization of water resources in this region.

Based on the conditions of infinitely aquifer and linear impervious boundary aquifer, the mixed strategy particle swarm optimization algorithm was applied to analyze the data of pumping tests for estimating aquifer parameters and provided a new method for estimating aquifer parameters. This mixed algorithm incorporates compaction into particle swarm optimizers algorithm to strengthen the local search ability of the algorithm. Combining with the control of scheduling coefficient to improve the convergence accuracy and speed. And the constraints of certain small probability improves global search ability. Then, the mixed strategy particle swarm optimization algorithm is established. The mixed algorithm can effectively solve the problem of slower convergence speed, poor accuracy and easily trapped into local extreme value, which appeared in particle swarm optimization algorithm. The results show that it is feasible method for estimating aquifer parameters. And the method has the advantage of high optimization accuracy, better convergence and better stability.

This paper defines the concept of spatial equilibrium of water resources firstly． That is，on the basis of ensuring the coordinated development among the three major subsystems of water resources，social economy and ecological environment in each computing unit，the coordinated development of different computing units is realized． Secondly，this paper introduces the concept of“coordinated development degree”into the study of the spatial equilibrium of water resources，and uses two levels of nested coordinated development as the metrics of spatial equilibrium． Based on the traditional water resource allocation model，this paper adds objective function and constraints of spatial equilibrium and then constructs the water resource allocation model based on spatial equilibrium． Finally，taking Yancheng City as an example，this paper constructs the water resource allocation model based on spatial equilibrium in Yancheng City and calculates the water resources allocation result under the 75% guarantee rate of 2020 in Yancheng City

The fishway in hydraulic facility provides artificial passages for the fish migration in the natural ecosystem． However，different swimming behavior of fish will be exhibited with respect to different characteristics water-flow velocity of various fishway inlets． In this paper， grass carp and cyprinoid are selected as the model fish based on the light sensitivity of most common juvenile cyprinid in Chinese rivers． In order to identify the favored water-flow velocity of model fish，the four characteristic velocities of fish activity ( respondent speed，critical speed，persistent speed and onrushing speed) are defined as the experimental observation indices． The correlation between the carp body length and the characteristic water-flow velocity of the juvenile cyprinid is tested by using the self-developed bionic device to imitate the water -flow through fishway． The formula between the characteristic water-flow velocity and

 Aiming at solving the problem of pile sinking in tidal areas，this paper proposes a new pile type-root pile． The root pile is taken as the research object． The indoor model test method is used to study the vertical bearing capacity of the root pile． The bearing capacity differences between the root pile and the circular pile and the anchor pile are compared and analyzed． The application examples of the root pile in the sea elevation observation of the Longgang and East Sichuan sluice in Yancheng City，Jiangsu are given． The results show that the vertical bearing capacity of root pile is higher than that of round pile and anchor pile． Meanwhile，the construction of root piles is also feasible，simple and practical． The research results in this paper ca

With the development of unmanned aerial vehicle(UAV) technology, UAV scanning technology has been applied widely home and abroad. However, due to its highly-priced, the application of big UAV is not sufficient in the current engineering. The paper introduced the application ways of small UAV in combination with its own experience in the whole life cycle of projects including the earlier-stage of the surveying and design, the application of construction phase, later monitoring and the result of exhibition, and so on. In addition, the paper focused on its practice mode in the fields of water conservancy and hydropower engineering, geological disaster management, and municipal engineering, so as to provide some ideas for the further development of UAV scanning technology, hoping to further promote the application of UAV technology in the engineering full life cycle.

Barrage and damming obstruct the migration of fish． Fish have a natural upstream habit and will be induced to the mainstream and migrate． In order to spawn，bait and migrate，fish cluster under the dam，thus generating the fish schooling effect． Fish schooling behavior is an important part of fish behavior research． Velocity，depth and turbulent energy are three important factors affecting fish schooling． In order to study the response pattern of fish schooling effect on the hydraulic characteristics under the dam，it is urgent for us to establish the correlation between the distribution rule of fish schooling and the above -mentioned three hydraulic factors． In this paper，the three - dimensional turbulence model is used to simulate the watershed under the dam in operating conditions during observation． The accuracy of the numerical simulation is validated by experiments． The distribution of the four major Chinese carps under the dam is observed by using observation instruments，and the relevance of schooling behavior and hydraulic characteristics are analysed． The results show that when the flow velocity is between 0．70～ 0．24 m/s，the number of fish body is positively correlated with velocity，and the optimum flow velocity range of the four fish groups is 0．060 ～ 0．12 m/s． When water depth is between 2．4 ～ 3．9 m，there is a positive linear relationship between the number of fish and water depth，and the lower limit of favorable depth of fish schooling is 2．8 m． When the turbulence energy is between 0～ 0．001 2 kg·m2 /s 2 ，there is a significant positive linear correlation between the number of fish and the turbulent energy，while performing a negative correlation when the turbulent energy ranges from 0．001 5 to 0．004 0 kg·m2 /s 2 ．And the optimum average turbulence energy of fish schooling is 0．000 50～ 0．001 2 kg · m2 /s 2 ．

Transient calculation results were carried out on free-surface-pressure flow in rectangular tunnel with arch crown by Preissmann slot method． Parameters and formulas of this type tunnel on hydraulic transient research were given． An applied engineering practice proved that a significant pressure suddenly occurred on the top of the tunnel while water occupied the section inside the tunnel from free flow to closed flow and a little pressure changing exists from closed flow to free flow，without considering the air volume on the arch crown air chamber． The more quickly of flow discharge variation，the more intense of the pressure changing is． The closer the tunnel section is to the position of flow discharge variation，the huger pressure of hydraulic transient is．

The main powerhouse on the left bank of Baihetan Hydropower Station is large in scale，complex in structure and geological conditions，and with a high tectonic stress level． The excavation of the cavern is caused by the failure of the highland stress brittle basalt at the top arch and arch foot，the large deformation of the rock wall rock of the main powerhouse and the stability of the rock mass caused by the C2 block between the weak layer and the fault zone． Based on the rock mechanics test，acoustic emission test and the results of the site geological exploration，the general rule of the main building block is summed up in view of the failure phenomenon of the main building block． In view of the large deformation phenomenon of the rock wall rock in the main building，the field monitoring is combined with the Midas numerical simulation ( Hoek-Brown failure criterion) ． The method is analyzed． It is concluded that the deformation of rock wall rock in the main building is closely related to the quality of rock mass and the development degree of fracture structure． In view of the problem of instability and failure of the wall block caused by the excavation of the cavern，the failure rules of the shallow block formed by the upper and lower wall of the wall are obtained by the mechanism analysis and the field investigation．

Abstract: The dam construction technique of CFRD in high-cold area is an important subject of construction of CFRD in poor natural condition. The number of CFRDs built in high-cold area with high latitude, high altitude, high evaporation and so on, has been more than 20 in our country, yielding substantial results. Through summarizing the experience and special problems of typical CFRD in high-cold area systematically, we discuss the problem, permeability coefficient and gradation curve, of bedding materials with dual function, summarize the project case of CFRDs’ frost resisting and cracks prevention, and analyze the damage mechanisms, caused by ice sheets, of panel concrete and surface watertight seal. In the end we suggest the countermeasures for the special problems such as bedding materials, concrete, watertight seal, construction and so on.

In order to study the phenomenon and mechanism of low-pressure atomization, a test rig of low-pressure jet nozzle atomization was built. Flow, atomization angle and atomization characteristics of atomization particle size of low pressure fine atomization nozzle aperture size 0.3mm, 0.5mm, 0.8mm and 1.0 mm in the pressure below 0.15MPa are researched by using high-speed photography equipment and MATLAB software to collect and analyze aerial images . The results show that the nozzle flow is positively correlated with the atomization pressure. The atomization angle increased with the increase of the pressure and is stable between 60 degrees and 80 degrees. the jet nozzle will appear in the axial direction after the dispersion of the phenomenon at the pressure of 0.08MPa,; atomization particle size and atomization pressure was negatively correlated, and smaller diameter nozzle at a smaller pressure atomization has larger particle size. The study of this paper provides guidances for the application of atomization and humidification under low pressure conditions.

Moistube-irrigation is a new water-saving irrigation technology with low energy consumption and broad application prospects. To reveal the effects of tube depth (D5, D15, D20) and pressure head (H100, H150, H200) on wetted zone under moistube-irrigation, an indoor experiment was conducted. Results showed that the diffusion rate of wetted zone in any directions under different pressure heads was: H200＞H150＞H100; The diffusion rate of wetted zone in the vertical upward and the horizontal direction under different tube depths were: D5＞D20＞D15, whereas that in the downward direction was: D20＞D15＞D5. The radius of wetted zone under different tube depth and pressure head was: H200＞H150＞H100 and D5＞D15＞D20. The effects of individual factors and their interaction on the values of Rmax followed the descending order of H＞D＞H*D, whereas that on the change rate of wetted-zone radius followed the descending order of H＞H*D＞D.

Abstract: In order to search optimal integrated management of water and fertilizer for citrus, an experiment was carried out to study the influence of different water and fertilizer coupling on photosynthetic characteristics. And ‘Shiranui’ citrus ripe for 7 years was selected as test material. There was a control treatment irrigated by conventional method (CK). And 2 irrigation levels( High Water and Low Water, irrigation amount was 80%, 60% of CK respectively), 3 fertilizer levels(High Fertilizer, Middle Fertilizer and Low Fertilizer, fertilizer amount was 85%, 70% and 55% of CK respectively) were set at heading and flowering stage (Ⅰ) and young fruit stage (Ⅱ), other stages were dealt as CK. The result showed that the net photosynthetic rate (Pn) varied as dual-peak regulation curve during the day. The transpiration rate (Tr) was increased in the morning and decreased in the afternoon. The stomatal conductance (Gs) and the intercellular CO2 concentration (Ci) presented the same diumal variation, which were decreased then lightly increased during the day for all treatment. Pn, Tr, Gs and Ci of the LW or LF were significantly lower than the CK but that of the HWHF were not significantly different from CK. Rewatering could increase photosynthetic parameters, and the gap between different treatments were narrowed compared with deficit state. The instaneous leaf water use efficiency (WUEi) was increased with more using of fertilizer and its variation causing by water was not same in different stage, but the highest instaneous leaf water use efficiency was observed in the HWHF. Pn of theⅠ-HWMF and the Ⅱ-HWHF were decreased by 7.62% and 6.08% respectively; WUEi of that were increased by 3.13% and 9.03%. Thus, the High Water and Middle Fertilizer treatment in flowering stage and young fruit stage and the High Water and High Fertilizer treatment in young fruit stage could not only keep the net photosynthetic rate but also increase the instaneous leaf water use efficiency.

Available nutrient state in the soil of jujube orchard directly affects crop growth and rational use of water and fertilizer. We had studied the spatial distribution and variation characteristics of soil available nutrients in jujube root area under drip irrigation and flood irrigation. The soil depth of the jujube orchard under 5 years of drip irrigation and flooding was analyzed by sampling and analysis. The results showed that NO3-N in the soil near the root zone decreased gradually with soil depth, and it gradually increased with distance from the root zone in the horizontal direction. Soil NO3 - N was lower at the beginning of growth period, and it increased gradually at the shoot growth stage. The coefficient of variation of NO3-N in drip irrigation and flood irrigation soil decreased with the increase of soil depth and horizontal distance, but drip irrigation decreased more than flood irrigation. During the initial stage of growth period, available N in soil decreased with the increase of soil depth, but the difference of available N in the horizontal direction was not significant, and the available N at the shoot growth stage increased sharply. Irrigation methods had little effect on the heterogeneity of available nitrogen. During the early stage of jujube growth, available potassium in the zone of the jujube root was higher than other soil layers. However, available potassium decreased rapidly at the shoot growth stage. The coefficient of variation of soil available potassium under drip irrigation and flooding conditions decreased with soil depth, but firstly decreased and then increased with horizontal distance. Soil available phosphorus was higher at the beginning of growth period and decreased rapidly at the shoot growth stage. The variation coefficient of drip and flooding irrigation treatments in horizontal direction decreased with the increase of distance, and the variation of drip irrigation was greater than that of flood irrigation. irrigation method had the greatest effect on the spatial distribution and variability of nitrate nitrogen in soil but had little effect on available nitrogen.

In view of the technical difficulties of subsurface drip irrigation，which is an emerging highly efficient and water-saving technique in the popularization and application of Minqin Oasis． The experiment and research are carried out from three aspects : dripper flow selection， drip irrigation depth and laying spacing． The changes of soil moisture the physical index and yield of corn ear are analyzed，and the technical parameters of buried drip irrigation suitable for the actual production of Minqin Oasis has been put forward． The practical problems in the popularization and application of subsurface drip irrigation has been solved． The utilization efficiency of water resources and has been improved and limited water resources has been saved to protect Minqin Oasis ecological environment from deteriorating．

Water and fertilizer integration technology is a new technology in modern agriculture that integrates irrigation and fertilization． It is of great significance to improving the utilization of water and fertilizer and reducing the environmental pollution in agricultural production． This paper studies the key devices in water and fertilizer integration technology，and uses the SolidWorks three-dimensional design software to establish a three-pass bypass fertilizer-applicator fertilizer-mixed fertilizer system structure based on parallel jet pumps，and uses FloEFD to perform flow field simulation analysis and system． The performance test shows that an effective reference model for a mixed fertilizer system is established． The test results show that under the action of 2．2 kW suction pump，the system can achieve stable and uniform suction of water and single element liquid fertilizer，and the maximum error of the actual value of the three-channel absorption fertilizer and the simulation value is 2．06%． The feasibility of the structural design of the fertilizer system provides a reference for the design and optimization of the automatic fertilizer spreader．

Qingshitan basin is located in Guangxi Province with a typical subtropical monsoon climate. Qingshitan basin has the characteristics of uneven spatial distribution of rainfall. Floods are easily happening in flood season, and there are water shortage problems in dry season every year. In this paper, with the use of one-dimensional hydrodynamic model(HD)and the rainfall-runoff model(NAM) coupling in MIKE 11 software, multiple sessions of the qingshitan reservoir inflow flood data is simulated and validated. The result shows that the applicability of NAM model in Qingshitan basin is not good. However, when coupled with MIKE 11HD model, NAM model can simulate the inflow flood of Qingshitan reservoir better.

In recent years，machine learning models，such as artificial neural network ( ANN) ，have made great progresses in many fields， such as deep learning model for image recognition and reinforcement learning model for go software AlphaGo． In this paper，a coupled machine learning ( CML) model for flood forecasting is proposed． The CML model couples the ANN with the K nearest neighbour method by a specially designed modelling approach and is trained by multi-objective genetic and Levenberg-Marquardt algorithms． The model resolves the insufficient foreseeable period ( only one time -step ahead) ，not able to simultaneously optimize the ANN topology structure and parameter，the local minimum，and poor performance of single ANN problems concerning the traditional ANN model applications． Ｒeal-world application of the CML model in the Tunxi watershed flood forecasting indicates its satisfactory performance and reliability，which enlightens the possibility of further applications of the CML model in flood forecasting

The flash flood prevention work has become an important fundamention work of water conservancy disaster prevention and reduction in China. Considering the sudden, strong and destructive characteristics of flash flood disaster, new requirements are put forward for the spatial analysis, modeling and optimization of GIS data. This paper takes the upper of Le'an River in Wuyuan County, Jiangxi Province as the study area, using GIS spatial analysis, modeling and optimization method to study the distribution of flash flood disaster, optimization the flash flood station network。According to the definition of disaster risk posed by the United Nations Department of Humanitarian Affairs, this study defines the risk of flash flood disaster as a product of hazard and vulnerability. The hazard model is based on the logistic regression model, and the vulnerability model adopts the transformation assignment function. Finally, the results of the risk assessment in upper Le'an River are obtained, and the flash flood disaster investigation and evaluation project identified in the key areas to verify the results. The study shows that the model of risk assessment of flash flood disaster can be applied to the classification of flash flood disaster risk in small scale.

This paper chooses Yueyang City as a vase study to construct MIKE21 and MIKE Urban coupling model．The storage facilities and the strong pumping station are taken into account． A total of 12 kinds of waterlogging scenarios are obtained． The results show that the main influencing range of waterlogging in Yueyang is the low top of the lake，and the simulated waterlogging point is consistent with the distribution of the main water points in the study area． The model simulation results are reasonable and reliable，which serve as a reference for the prevention and control of waterlogging in the lakeshore cities in plains

Use transient flow calculation method, proves Bowa hydropower station replaced tailwater surge chamber as draft tube gate chamber is practical,shows the principle and process of hydraulic calculation,and calculation results meet to the design standard requirements, the maximum vacuum degree of hydroturbine draft tube after load rejection is 3.3.m, and little fluctuation in water-diversion system is stable. In large size tailwater surge chamber construction, replaced tailwater surge chamber as draft tube gate chamber can avoid the risk of excavation under unfavorable geological condition.

In order to achieve both hydropower generation and water supply，some hydropower stations with high water quality provide water to downstream areas by drawing water from the headrace tunnel． This paper takes the South Water Ｒeservoir Project as an example to study the transient process of the water conveyance system combining power generation and water supply by using the numerical method． Firstly，a mathematical model of the hydropower and water-supply system of the selected project is established． Then，the adjusting method of the initial parameters of the steady flow case and the interaction of hydropower and water -supply systems in the transient process under the three operation modes are analyzed． Finally，the numerical analysis ideas for transient process are induced in order to provide a design basis for this type of power generation and water supply engineering

In order to explore a simple and convenient method for obtaining specific water capacity，the relevant basic physical and chemical parameters of the soil，the soil water characteristic curve and specific water capacity are tested in the soil of the Loess Plateau in Shanxi Province． The parameters of the specific water capacity model are fitted and measured． Based on an analysis of the relationship between the basic physical and chemical parameters of each soil and the parameters of the water capacity model，a BP neural network prediction model is established on the soil texture，soil bulk density，soil organic matter content，and soil inorganic salt content． The results show that the BP neural network prediction model based on soil texture，soil bulk density，soil organic matter content and soil inorganic salt content are feasible，and the average relative error between the measured and predicted values of the water capacity model parameters is lower than 10%， prediction and accuracy are better． The research results provide theoretical and technical supports for obtaining specific water capacity，and promoting the development of soil transfer function theory．

This paper presents a geotextile containers technique to stabilize the slope of agricultural ditch against the problems of partial slip and collapse in the irrigation and drainage engineering of Yellow River irrigation districts, Ningxia. An overview on the design and construction method was introduced to proctect the agro-ditch with geotextile containers for high standard farmland construction project from Dong Fanghong Village, Shaogang town where is located to Qing Tongxia irrigation area of Ningxia. The plan was formulated and the equipments were installed so as to conduct monitoring survey task. The data were analyzed and dicussed based on the information of prototype monitoring experiment from November, 2016 to November, 2017. And the results were compared to the monitoring data of traditional way which reinforces slope with grass-soil and wood-pile on the agro-ditch at same term. It has the advantage of showing more stable to ditch slope than original mode.