Based on the SRTM digital elevation DEM model, using the hourly precipitation data of Chongqing from May to September 2017 to 2021, this paper analyzed the temporal and spatial distribution characteristics of short-term heavy precipitation under different terrains in Chongqing, and discussed the relationship between the frequency and intensity of short-term heavy precipitation and topographic factors. The results show that the spatial distribution of short-term heavy precipitation in Chongqing is uneven. The overall average frequency high value area of the previous year and stations ≥ 60mm/h are mainly located near Huaying Mountain in Northwest Chongqing, Daba Mountain in Northeast Chongqing and Wuling Mountain in Southeast Chongqing; For the station average frequency of short-term heavy precipitation in Chongqing, the monthly variation shows a significant single peak type, and the frequency is the most in July; The diurnal variation is bimodal, with the main peak occurring most frequently at 03:00-05:00 and the secondary peak occurring more frequently at 16:00-19:00. The frequencies of the north and west slopes are slightly more than those of the other slopes. The frequency of flat slope and gentle slope is more than that of other slopes. The frequency of 500-1 000 m and > 1500 m is more than that of other altitudes; The fluctuation ≤30 m and 30-200 m are more frequent than other fluctuations; When slope ≤15°, altitude ≤1 000 m, and undulation ≤200 m, stations with precipitation intensity ≥100 mm/h appear, indicating that appropriate mountain topography is conducive to the increase of short-time heavy rainfall intensity. The research results can provide reference for near early warning, disaster prevention and reduction of short-term heavy precipitation in Chongqing.

In order to explore the temporal and spatial variation of annual precipitation and the type of precipitation field in Heilongjiang Province, this paper analyzed the precipitation of Heilongjiang Province from 1980 to 2020 using the Mann-Kendall test method, EOF decomposition method, Morlet wavelet analysis and other methods commonly used in modern climate statistical diagnosis. The results show that the precipitation tendency rate in Heilongjiang Province from 1980 to 2020 is 15.52 mm/10 a, that is, the precipitation has a significant upward trend. The precipitation in summer accounts for about 65% of the whole year, and only 3% in winter; Under the influence of topography and climate, precipitation in Heilongjiang Province showed significant spatial differences. As a whole, the south and central regions have higher precipitation, followed by the east, and the west and north regions have lower precipitation. According to the EOF decomposition, the precipitation in Heilongjiang Province can be divided into three modes and six precipitation fields: the first mode indicates that the precipitation in Heilongjiang province is more or less; The second mode showed that the central and northeastern parts of the province had more precipitation, while the southwest and Greater Khingan Mountains had less or opposite precipitation. The third mode showed that the precipitation was higher in the southwest of the province, and less or opposite in the southeast and Greater Khingan Mountains. There were two scale variation cycles of precipitation in Heilongjiang Province, 11-30 a and 3-7 a, with 28 a as the first main cycle.

Drought index is crucial to the study of drought. With the influence of climate change and human activities, the frequency distribution of hydrological time series changes with time, so the nonstationary of drought index needs to be considered. The standardized precipitation index (S_SPI) considers that the precipitation obeys the Gamma distribution, the corresponding distribution function parameters are usually stationary and invariable. The actual distribution function parameters have a certain correlation with the time series. Therefore, based on the GAMLSS model, the nonstationary Gamma distribution model of precipitation series was constructed with time series as covariate. The nonstationary standardized precipitation index N_NSPI was calculated. Taking Yunnan Province as an example, the monthly N_NSPI and S_SPI during 1960 to 2019 were calculated respectively. Comparing the two indices, it is found that the overall trend of drought recognition results of the two indices is similar. However, in 1960~1985, the number and grade of droughts identified by N_NSPI were stronger than those identified by S_SPI, and the two were similar in 1986~2005. In 2006~2019, the number and grade of droughts identified by S_SPI gradually exceeded those identified by S_SPI. Further analysis shows that the N_NSPI with considering the time-varying distribution function parameters can more accurately reflect the actual drought situation.

In recent years, it causes disasters increasingly by too much or too little precipitation. Therefore, accurate prediction of precipitation is of great significance and practical application value to human life and social development. Based on the monthly precipitation data of Zhengzhou from 1990 to 2019, monthly precipitation was forecasted from 2020 to 2021 by utilizing SARIMA, Prophet and LSTM model, respectively. In order to improve the prediction accuracy of the model for monthly precipitation, two combined models of the SARIMA-EMD-LSTM and Prophet-EMD-LSTM were proposed. Empirical analysis shows that the proposed two combined models have higher prediction accuracy and decrease the root mean square error significantly. Furthermore, Prophet-EMD-LSTM model has comparatively better prediction effect. The monthly precipitations in Zhengzhou from April to December, 2022 were forecasted with higher precision.

Based on the monitoring data of 36 meteorological stations in Jiangxi Province from 1960 to 2018, the characteristics of drought change and the correlation between SPEI index and M-K trend test. The results show that the SPEI-12 index showed a slight downward trend, and drought and flood alternated from year to year. The annual drought mainly distributed in the northeast, west and southeast of Jiangxi Province, and most of the drought was global and regional, and the regional drought was more significant after 2000. The seasonal drought occurred in summer and autumn, especially in autumn. The drought degree in spring and winter was light and more frequent in the southern part of Ganzhou. However, after 2001, spring showed an aridity trend, and the SPEI index in summer, autumn and winter showed an upward trend, even easy to cover the province's serious autumn drought. Crop to the affected area and summer and autumn were significantly correlated with SPEI index and summer drought influence on Jiangxi crops than autumn drought. The results can provide reference for drought control and drought resistance in Jiangxi Province.

In order to explore the impact of landfall typhoons in China's coastal areas, based on the typhoon data and socioeconomic data from 1949 to 2020, M-K trend analysis, R/S analysis, wind and rain analysis, and disaster quantification and other research methods were used to comprehensively analyze the temporal and spatial changes, wind and rain characteristics and disaster situation of landfall typhoons in China. The research results show that the number of typhoons landing in China is decreasing, and the duration is prolonged. In terms of intensity, there is a situation of "weak decrease and strong increase", and the landfall sites are shifted to the east and north. Both the wind speed and precipitation of the landfall typhoon showed an upward trend. Considering the maximum value, it was found that the wind speed and precipitation showed a significant increase trend. The impact of typhoon has gradually evolved into a disaster pattern that has shifted from the secondary industry to the primary and tertiary industries. The research results can provide data support and scientific basis for reducing the economic losses of typhoon disasters.

The precipitation and ice melt water supply in Huma River Basin have a great impact on the runoff changes of the main stream of Heilongjiang Province. Climate change is an important factor affecting the precipitation and ice melt water of the Huma River. By collecting the data of Huma, Xinlin, Tahe, Huzhong meteorological stations and Humaqiao hydrological stations in the basin, combined with the DEM data, land use data and soil data, a SWAT runoff model suitable for the basin was constructed to simulate the monthly runoff. At the same time, the response of runoff to climate change in the basin was studied by setting temperature and precipitation gradients through the weather generator. The results show that the SWAT model has good adaptability in the basin, and the R² and N_NSE in the calibration and validation periods have reached the evaluation standard of the model. The runoff of Huma River Basin is much more sensitive to precipitation changes than temperature, and precipitation is the main control factor of runoff changes in the basin.

It is of great practical significance for flood control and drought relief in the basin to accurately identify the variation characteristics of the extreme value of "hydrological consistency" caused by changing environment. Therefore, this paper took the Yellow River basin with significantly reduced runoff as an example. Firstly, The Mann-Kendall test method and univariate linear regression method were used to accurately identify the abrupt and trend characteristics of runoff at important hydrological stations in the main stream of the Yellow River. Secondly, 13 hydrological characteristic indexes were used to reveal the temporal and spatial variation law of hydrological characteristics of the basin under the condition of inconsistency. The results show that the annual runoff of Tangnaihai, Toudaoguai, Huayuankou and Lijin stations decreases year by year at the rate of 27.46, 105.75, 172.20 and 141.37 m³/(s·10a) respectively, and the abrupt change years are 1989, 1992, 1992 and 1984 respectively. Before and after runoff variation, 13 hydrological characteristic values vary in time and space scale, and the change degree in the middle reaches is large, and the source area is small. The research results provide important theoretical support for determining the development and utilization mode of water resources in the basin.

A SWAT model of the upper Paraná River basin in Brazil was constructed to test its applicability in largescale watershed. The sensitivity parameters of the model were analyzed. Then the model was calibrated and validated using 17 runoff stations. The results show that the soil evaporation compensation coefficient (ESCO) and the SCS runoff curve number (CN2) are the most sensitive parameters for the sub-basins with a high density of rain gauged stations, the model could simulate the discharge well after calibration, and the R² values of 11 stations among 17 calibration stations were greater than 0.5; Affected by factors such as insufficient precipitation data and changes in land use, the model in validation period did not perform as well as in the calibration period. Thus, the SWAT model could be used as an effective tool for large-scale watersheds, but the simulation accuracy largely depends on the quality of precipitation data.

In light of the difficulty of traditional single runoff prediction models to describe future variation in runoff, a monthly runoff prediction model named AVMD-GPR-CK based on adaptive variational modal decomposition (AVMD) and Gaussian process regression (GPR-CK) with physically composite kernel was proposed. In the proposed model, the runoff series was decomposed into several subseries using AVMD. Then subseries were separately modeled according to their own characteristics, and the final prediction result was the superposition of the subsequence prediction results. The AVMD-GPR-CK was applied to forecast the future 1-12 months runoff at Xiangjiaba station in the Jinsha River basin. The results show that the deterministic coefficient of the AVMD-GPR-CK model is greater than 0.94, and the mean absolute percentage error (M_MAPE) is within ±17% for all leading times, and the M_MAPE is inside ±10% for leading times within 10 months. Furthermore, the accuracy of the AVMD-GPR-CK is significantly better than those of the commonly used BP, GRNN, RBF, and RELM models.

Revealing the characteristics of basin runoff evolution and quantitatively identifying the contribution of driving factors is essential for adaptive water resources management and water security in basins. Based on the measured monthly runoff series from 1960-2015 at the NO.2 hydrological station in the source area of the Ulungur River and the meteorological and human water and soil resources development and utilization image data for the same period, the sliding removal wavelet analysis method, the Mann-Kendall trend test method and the sliding t test method were used to analyze the evolution trend and mutation characteristics of the hydrometeorological elements sequence. The elastic coefficient method based on the Budyko hypothesis was used to identify the contribution rates of climate changes and human activities to runoff change in the study area. The results show that there is a non-significant upward trend in runoff series, a significant upward trend in precipitation series and a significant downward trend in potential evapotranspiration series in the Ulungur River source area; The runoff series changed abruptly in 1995, with the sensitivity coefficients of runoff to precipitation, potential evapotranspiration and subsurface characteristics increasing by 8.8%, 25.0% and 7.8% respectively in the change period 1995-2015 compared to the base period 1960-1994; The contribution of changes in precipitation and potential evapotranspiration and subsurface characteristics parameters to runoff changes are 39.2%, 7.0% and 53.8% respectively. The runoff changes in the study area are driven by a combination of human activities and climatic elements, with human activities being the main driving factors.

Aiming at the cumbersome problem of applying the Markaviev method to calculate the bed-forming flow rate, the geomorphic work diagram method was proposed to simplify the calculation of the bed-forming flow. Based on the measured water and sediment data from 1960 to 2014 at the four hydrological stations of Huayuankou, Gaocun, Aishan and Lijin in the lower reaches of the Yellow River, the Markaviev method and the geomorphological method were used to calculate the bed-forming flow of the four stations over the years. The results show that the differences in the bed-forming flow over the years at the four stations in the lower reaches of the Yellow River calculated by the two methods are small and the downward trend is similar. Compared with the Markaviev method, the geomorphic work diagram method is more convenient and accurate to calculate the bed-forming flow.

Due to the disturbance of human activities and the influence of climate change, the water area of Mudong Lake, the core area of Huixian Wetland, the largest karst landform original wetland in the Lijiang River Basin, has shrunk and faced severe ecological and environmental risks. Using the Sentinel remote sensing image data of 65 scenes from 2017 to 2021, the water area of Mudong Lake was extracted by random forest classification. The temporal and spatial changes of the water area of Mudong Lake in the past five years were analyzed to explore the correlation between the water level and area of Mudong Lake. The results show that the water area of Mudong Lake has been relatively stable in the past five years, but the changes in the wet and dry periods are obvious; The area changes are mainly distributed in the northern part of the lake area; The correlation between water level and area is relatively good, and the correlation coefficients of different water periods are different; The correlation coefficients of the wet periods and dry season are 0.90 and 0.60, respectively.

Optimal allocation of water resources is an important method to effectively relieve the contradiction between the supply and demand of water resources in regions. The traditional butterfly optimization algorithm (BOA) has some defects, such as low search accuracy, slow convergence speed, easy to fall into local optimization and can not be directly used to solve multi-objective optimal allocation of water resources problems. It was improved by introducing the methods of fast non dominated sorting, congestion and elite strategy, and the superiority of the ameliorative butterfly optimization algorithm (ABOA) was verified by using ZTD function. Finally, the ABOA was applied to the optimal allocation model of water resources in Handan, and the scheme with the least water shortage was selected as the final scheme from the Pareto front. The Handan water resources optimal allocation in 2035 (p=50%) yielded a total water demand of 2.74 billion cubic meters, a total water distribution of 2.44 billion cubic meters, and the water shortage was 298 million cubic meters, and the water shortage rate was 10.9%. Domestic and ecological water demand could be fully met. However, the primary, secondary and tertiary sectors were still facing water shortages in different regions, which need to be alleviated by water conservation. The research results can provide a new reference for the solution of multi-objective optimal allocation of water resources.

In order to enhance the efficiency and rationality of water resources allocation in Minjiang River, a water allocation index system including the monitoring rate of water intake, the rate of water quality of control sections meeting the standards and the early warning of discharge was established from the perspective of water resources management and assessment effectiveness. And then the quantitative calculation of the water intake of each water-taking city and the importance of each index were carried out by the comprehensive weighting method which combines the subjective and objective factors. The results show that the results of water intake distribution are consistent with the actual of water diversion, and the demand of water resources in Chengdu, Meishan and other cities in the middle reaches of Minjiang River is large, which can provide a basis for water resources regulation and water rights trading in Minjiang River. The supervision rate of water intake and the rate of water quality of control section are of great weight among the 6 new indexes, which provides an idea for constructing a new index system of water allocation. The results of water diversion take into account both the health of rivers and the requirements of water environment, and try to directly link the benefits of water resources management with water diversion, which can provide reference for actual water diversion, and urges each area to have the emphasis to continue to do well the water resources management and the appraisal related work.

The problems, such as unreasonable development of small hydropower and the neglect of the river ecological flow demand, can negatively impact the hydrological ecology of the lower reaches and damage the habitat environment of aquatic organisms. Taking the Xiaxiang hydropower station in the Dahuan River Basin of Guangxi Zhuang Autonomous Region as the research reach, carp was selected as the target fish. Based on the suitability curve of carp velocity and water depth, using the habitat simulation, the characteristics of hydrodynamic distribution and carp mass habitat area distribution under 11 flow conditions were analyzed. The results show that the suitable ecological flow of target fish in dry season is 9.38 m³/s, and the minimum ecological flow is 6.25 m³/s. The comparative analysis was carried out by using the hydrology method, and the suitability of the minimum ecological flow was evaluated by three evaluation indexes. The results show that the suitable ecological flow and the minimum ecological flow of the habitat simulation are reasonable and suitable. The research results are of great significance to ensure the ecological environment health of the downstream rivers of small hydropower stations.

In order to understand the temporal and spatial characteristics of blooms in the Three Gorges Reservoir, the temporal and spatial changes of dissolved oxygen, Chlorophyll-a and other indicators were analyzed, and the growth characteristics of algae was screened, which can provide reference for the early warning of blooms under the condition that no blooms occurred in Xiangxi River bay of the Three Gorges Reservoir in June 2020. The results show that the thermocline and the surface layer of the inverted weight current block the vertical hydrodynamic exchange, and then promote the presence of oxygen thermocline at the bottom of the water surface. Consecutive sunny days in summer may increase the chance of bloom outbreaks from 7:00 to 11:00 and from 14:00 to 17:00. There is a lag in bloom outbreak. Algae growth cannot be characterized only by the density of algae in monolayer water, so it is necessary to use the average density of algae in the vertical migration range for further bloom warning.

As an important factor in the ecological environment of lakes, aquatic plants play a key role in the restoration and management of lakes. The water blocking effect of aquatic plants has a significant impact on the flood storage and discharge process of lakes, so the impact of aquatic plants on the roughness has become an important part of the hydraulic research of ecological lakes. The height of aquatic plants is closely related to the roughness of lakes. The elastic modulus of aquatic plants is an important mechanical property parameter for calculating its deformation. The stem of aquatic plants is simplified as a cantilever beam with variable cross-section. Through the bending deformation test of eight aquatic plants, the tensile force, displacement and other parameters are measured, and the elastic modulus value is calculated. The basic range of the measured elastic modulus change of eight aquatic plants is obtained. The comparison shows that the elastic modulus of these aquatic plants increases with the growth age or total length.

In order to study the effects of plants on the migration and accumulation of nitrogen in the biological retention system, and promote the vegetation construction of rainwater biological retention system in loess distribution area, 5 groups of biological retention system simulation devices were constructed by selecting Iris, Hemerocallis, Sedum, Ophiopogon and non-plants. The migration of nitrogen in fillers and the accumulation of nitrogen in each medium under different plant treatments were investigated. The results show that there was a close relationship between plant nitrogen accumulation and plant biomass increase during the experiment, which was as follows: Sedum> Iris>Hemerocallis> Ophiopogon. The nitrogen absorbed by plants was mainly accumulated in the upper structure of plants. The distribution difference of in the five groups of biological retention system fillers is not significant and the content of is low. is mainly removed in the upper part of the packing layer by adsorption, and each system has a good removal effect on . Plants have a significant effect on the distribution of in the packing and the migration of in the system. Compared with the non-plant group, the system with plants can reduce content in the filler, and the lower the content in the filler before influent, the lower the effluent concentration. The average TN removal rates of 5 treatments were as follows: Iris (50.59%)> Sedum (43.99%)> Hemerocallis (37.85%) Ophiopogon > (30.51%)> non-plant (26.09%).

It is of great significance to discuss the relationship between ecosystem services and matching status of water and land resources for the sustainable utilization of ecological resources. Therefore, the equivalence factor method, matching coefficient of water and land resources, and coupling coordination degree model were used to reveal the spatiotemporal evolution characteristics of the ecosystem service value, matching status of water and land resources, as well as the coupled coordination relationship between them in China. The results show that the total value of ecosystem services in China increased 2144.45 billion yuan. The overall spatial pattern of the ecosystem service value per unit area was high in the south China and low in the north China, and the ecosystem service value per unit area in all provinces except Shanghai was improved during the study period. The matching coefficient of water and land resources in China continued to decrease, showing a clockwise spatial variation characteristic of first decreasing and then increasing roughly with Qinghai province as the endpoint in space. The coupling coordination degree between ecosystem services and matching of water and land resources in China from 2010 to 2018 first increased and then decreased, and the overall belonged to the basic coordination type, which was in transition. The coupling coordination degree shows the spatial distribution characteristics of high in the south Chin and low in the north China. The results can provide decision-making basis for the policy formulation of coordinating ecological protection and water and land resources utilization.

Taking the upper reaches of the Yangtze River at Guangyang Dam as an example, a physical model was constructed to analyze the changes of water depth and flow field in the corresponding river section before and after the implementation of the continuous pool-riffle type natural habitat restoration technology scheme. And then the effects of the habitat restoration scheme on fish spawning grounds, habitats, overwintering activities and waterways were discussed. The study show that after the implementation of the habitat restoration scheme, the area of the slow flow area in the test reach increased significantly, and a local slow flow was formed between the group of spur-dike, which was conducive to fish spawning and habitat; The implementation of the scheme did not adversely affect the vessel traffic in the channel of the river.

In order to scientifically evaluate vulnerability of heavy rainfall and waterlogging in subway Stations, determine the sensitivity index as well as improve the management level of the heavy rainfall and waterlogging in subway stations, an evaluation method based on IOWA-VAC was proposed. Firstly, an evaluation index system was constructed based on Pressure-State-Response (PSR) theory. Then, the index data was reordered in ascending order by using the IOWA operator, and the final weight of the new data was obtained by introducing coefficients θ to dynamically adjust the interval boundary weights. The Vector Angle Cosine (VAC) was introduced to test the closeness of the consistency between the target score vector to be evaluated and the ideal target vector, so as to realize the transformation from algebraic thinking to spatial geometry thinking, and the target grade to be evaluated was obtained. Single factor sensitivity analysis was used to determine the sensitivity index. The practicability of the evaluation model was verified by taking the Yansi station of Zhengzhou Metro Line 5 construction projects as examples. The results show that the vulnerability level of the Yansi station of Zhengzhou Metro Line 5 is Ⅳ, with high risk. Thus, it provides feasible suggestion for vulnerability management of heavy rainfall and waterlogging in subway stations.

In order to reveal the process and mechanism of outbreak of flash floods and causing disasters in ungauged areas, a numerical model of the transport of loose bodies under heavy rainfall floods was established in the Xiangxi River subbasin of Zhangshu City, Jiangxi Province. The process of heavy rainfall and the law of sediment transport were analyzed. The results show that for the river, the flow velocity is higher at the high terrain, slope drop change and the confluence area, and for the area with gentle slope and large catchment area, the increase of flow velocity at the confluence point is especially significant compared with other areas; The local water accumulation at the beginning of the basin, surface runoff occurs in a short period of time, and the gathered water scours out several gullies, and sediment is mostly deposited at the downstream outlet; The water depth and flow velocity of the basin are related to the rainfall. The greater the rainfall, the greater the water depth and flow velocity is, the more significant the scouring situation is. This study has positive significance for flash flood warning in the region.

Aiming at the shortcomings of insufficient population diversity, easy to fall into local optimum, and slow initial solution speed of intelligent water drops algorithm (IWD), an improved IWD algorithm (IIWD) was proposed, which introduces the Logistic chaotic initialization method and the differential variation operator of the difference evolution algorithm (DE), and improves the neuronal update mode of the self-organizing mapping algorithm (SOM) and introduces it into the sub-update process of the optimal individual of the IWD algorithm. The IIWD was applied to the peak shaving scheduling of cascade reservoir groups. Compared with IWD and DE, the efficiency of the IIWD was verified.

Currently, the electricity market is undergoing a new round of reform, and deviation assessment mechanisms have been introduced in various places to promote fair competition. In the face of the new market rules, the traditional dispatching model with maximum generation cannot be applied, and hydropower companies need to take market factors into account to control deviations. In order to save hydropower companies from paying costs, a study was conducted on the deviation control rules, and a bi-level optimization model with the objective of maximizing generation capacity and minimizing deviation was established to facilitate trading decisions. Taking the Three Gorges hydropower plant and Hubei province electricity market as examples, the Harmonic Search algorithm was used for analysis. The results show that the deviation rate in each interval is within the deviation control range, and the hydropower plant is exempt from deviation control. Thus, the bi-level optimization model mentioned above is feasible.

In order to realize the remote mobile monitoring of the dam, the automatic identification of important defects and the measurement of key monitoring equipment, the research on the intelligent mobile inspection technology of dam safety based on image recognition technology and track robot was carried out. Firstly, an intelligent mobile inspection system for dam safety was constructed based on the orbital robot. On this basis, the automatic identification of typical dam defects and the measurement of key monitoring equipment were realized based on image recognition technology. It had been applied in a dam with good results. The remote and large-scale inspection of dam safety was realized, which can significantly reduce the workload of manual inspection, replace manual inspection under extreme natural conditions, and timely grasp the operation of hydraulic structures such as dams. The research results can provide important reference and technical support for the safety monitoring of dams.

Robotic total station plays an important role in long-term, continuous and automatic displacement monitoring of reservoir dams. But the reliability of the monitoring results is easily affected by atmospheric refraction. Based on the theoretical analysis of the meteorological correction model and reference point differential correction model, the applicability of atmospheric refraction correction model was experimentally analyzed by using the automatic monitoring system based on robotic total station established in Wanmipo power station. The results show that for small monitoring areas, only using the meteorological data at the station for correction can achieve good results, and the accuracy of reference point differential correction model is equivalent to that of meteorological correction model. It has reference value for the construction of dam automatic monitoring system based on robotic total station.

In order to explore the influence of geographical location (latitude) differences on the water temperature of the reservoir area, the temperate Gongguoqiao Reservoir and the tropical Jinghong reservoir, which are similar in scale and operation mode, were taken the research objects. Based on the prototype observation data, the CE-QUAL-W2 model was established to compare and analyze the water temperature distribution characteristics of the Gongguoqiao and Jinghong reservoir. The results show that the CE-QUAL-W2 model can be applied to the simulation of temperate and tropical reservoirs, and the difference of water temperature changes in reservoirs in different climatic zones can be clarified. The temperature increase and decrease of the surface water temperature in the Jinghong reservoir area obviously lags behind the surface water temperature in the Gongguoqiao reservoir area. Both Gongguoqiao and Jinghong reservoir are weakly stratified reservoirs. Gongguoqiao Reservoir is weakly stratified in spring and summer, while the stratification in autumn and winter is not obvious. Jinghong Reservoir shows weak stratification in summer and autumn, but not in spring and winter. The results can provide reference for water temperature research of similar-scale power stations on the Lancang River.

Most existing parameter inversion methods of the dynamic constitutive model parameters do not take the concept of uncertainty into account. Therefore, the adaptive cloud transformation algorithm (AGCT) was combined with RBF neural network (RBFNN) to construct an adaptive cloud neural network parameter inversion model (AGCTNN), which converts the uncertainty concept into quantitative values and better takes into account the influence of the randomness and ambiguity between dam systems on the inversion of dynamic parameters. AGCT was compared and analyzed with three traditional clustering algorithms, K-Means, SOM and DBSCAN, to verify the superiority and feasibility of the algorithms. The inversion analysis was then carried out on engineering examples using two inversion models, AGCTNN and RBFNN. The results show that the positive coupling results of the proposed inversion model are in better agreement with the measured values, and the error range between the measured and inverse values of peak acceleration at measurement points is reduced from 8.73%-25.17% to 2.31%-8.16%, which confirms the reasonableness of the inversion model and the possibility of its application in practical engineering.

The structural joints of face rockfill dam are the most important part and the weakest link of the seepage control system of dams. Taking a face rockfill dam as an example, the position, width, length of vertical failure joints and permeability coefficient of cushion area were simulated by finite element method. And then the seepage field law and permeability stability after water stop failure were studied. The results show that in the case of single fracture failure, the position, width, length of fracture and permeability coefficient of cushion are positively correlated with control factors of seepage flow, and the length of vertical fracture and permeability coefficient of cushion are the most significant. When multiple joints fail simultaneously, the seepage flow at cracked panel can be calculated by summing the failure results of single joints, and the results are safety. At the same time, it is suggested that the permeability coefficient of cushion should be 1×10^-5m/s or slightly smaller. The results can provide reference for the design and construction of similar projects.

Aiming at the large-scale backflow problem in the forebay with large forward diffusion angle of the pumping station, based on the CFD software, the RNG κ-ε model was used to simulate the flow state of the forebay of a pumping station. The hydraulic characteristics of the forebay under the original scheme were analyzed. The rectification effect of the figure-eight-shaped diversion piers was explored. The results show that adding figure-eight diversion piers in the forebay could effectively eliminate the large-scale backflow on both sides. The backflow area of the plane flow field disappeared, and the uniformity of the axial flow velocity distribution of the side unit was improved by 11.03% and 11.32% compared with the original scheme. The research results can provide a reference for the rectification of the forward forebay pumping station.

When the water conveyance tunnel in long-distance water diversion project passes through the potential earthquake area, there is a major engineering safety hazard caused by active fault dislocation. It is of great engineering significance to reveal the influence of fault dislocation on the stability of water conveyance tunnel. Based on ABAQUS finite element analysis software, considering the complex dynamic interaction characteristics of surrounding rock, fault, lining and internal water, the three-dimensional numerical simulation of surrounding rock-fault fracture zone-lining-internal water system was carried out, and the influence of different fault dislocation momentum, width and cohesion on the stability of water conveyance tunnel was analyzed in depth. The results show that the vertical displacement and damage degree of the lining structure of the water conveyance tunnel decrease under the conditions of small fault dislocation, fault width and large fault cohesion, which has a certain reference value for the theoretical study of the dynamic response of the water conveyance tunnel across faults.

Roughness is an important parameter which reflects water transport capacity of water diversion project. The roughness value can be calculated by observing the frictional head loss. However, how to estimate the roughness is always a difficult problem in hydraulics for the new unworked water diversion project. The surface roughness of water conveyance buildings is a vital factor affecting the roughness value. So, this study proposed a surface roughness measurement method relies on hierarchical sampling. Taking a new in-situ reinforced concrete lining tunnel as an example, the statistical distribution of surface roughness and the minimum sample size of tunnel roughness estimation were analyzed. On this basis, the roughness value range of the tunnel project was estimated, which has a certain reference significance for predicting the water transport capacity of the new project and inspecting the construction quality of the lining.

As a diversion tunnel, the pressure distribution of the tunnel body, the top and the bottom of the tunnel is very important to avoid cavitation, vibration and other undesirable phenomena. Taking the diversion tunnel of Yebatan Hydropower Station as the research object, this paper simulated the pressure distribution of the diversion tunnel based on the physical model test, as well as the three-dimensional numerical model established by the RNG k-ε turbulence model and the VOF method. The reliability of the three-dimensional numerical simulation was verified by the experimental data. The results show that the main flow of the diversion tunnel, the pressure distribution of the tunnel body at the sudden change of hydraulic boundary such as the inlet chamber section, the turning section and the plug section, as well as the variation trend of the bottom and top pressure along the way were analyzed. The research results show that the pressure distribution along the bottom and top of the diversion tunnel shows a downward trend, but at the sudden change of hydraulic boundary such as the sluice chamber section, the plug section and the turning section, the pressure value will show a large fluctuation of rapid increase or decrease.

sedimentation basin is one of the important water conservancy facilities to reduce the sand content of water flow in agricultural irrigation projects, which plays an important role in reducing the sand content of water flow and improving the utilization rate of water flow. In order to improve the efficiency of sand sedimentation basin discharge, a linear sand collection culvert structure was designed based on the S-type structure of the sedimentation basin in the Weigan River dry canal. The hydraulic characteristics of the S-type and linear sand collection culvert water flow were clarified by combining the experimental results of prototype observation with physical model tests and numerical simulations. The experimental results show that Fluent software can effectively simulate the operation process of local sand traps; Due to the low flow velocity at the end of the S-type sand trap, the sediment accumulation in the sand trap is caused, while the linear structure effectively increases the overall flow velocity in the sand trap, and the flow velocity in the corridor at the end of the sand trap is increased from 0 m/s to 0.4 m/s-0.7 m/s, thus improving the sand discharge efficiency of the sand trap. This study can provide scientific basis and technical support for optimizing the structure of the sand sink and improving the sand discharge efficiency of the sedimentation basin.

Flexible mattress is a beach protection measure which is widely used in the waterway regulation projects in the middle and lower reaches of the Yangtze River. The in-situ service condition of the flexible mattress has a great impact on the protection efficiency for the beach and shoal. Aiming at the difficulty of identifying and quantifying the deformation of the bulge of the flexible mattress, a model test was carried out to study the strain response characteristics of the bulge deformation. The result shows that the strain under bulging deformation presenting a parabolic strain distribution characteristic on the cross-section, and the area with the largest strain is located on the top of the bulging body. Based on the strain distribution characteristics of bulge deformation, the shape prediction formula was proposed. Furthermore, the bulge deformation identification method and shape inversion method were put forward. The results can provide the reference for the deformation monitoring and assessment of the flexible mattress.

A static dynamic triaxial instrument was used to carry out concrete triaxial dynamic mechanical tests by setting different strain rates (10^-5/s, 10^-4/s, 10^-3/s, 10^-2/s) and different lateral confining pressures (4.5 MPa, 6.0 MPa, 9.0 MPa and 12 MPa). The evolution law of the total energy density, elastic strain energy density and dissipated energy density of concrete with axial strain under dynamic triaxial compression was studied. The influence of lateral confining pressure and strain rate on the energy evolution law of concrete was analyzed. The results show that with the increase of axial deformation, the total energy density and dissipated energy density of concrete increase nonlinearly, and the elastic strain energy density first increases and then decreases. The increase of strain rate and lateral confining pressure improves the specific energy storage limit of concrete, and the energy storage limit of concrete shows a strong rate sensitivity; The relationship of energy storage limit and the lateral confining pressure is approximately linear; With increase of the lateral confining pressure, the rate sensitivity of the concrete energy storage limit shows a decreasing trend.

The deep learning technology was used to study a method of predicting the performance of SCC based on the mixture image information during the mixing process. Twenty-five sets of videos of the SCC mixing process with different performances were recorded. According to the slump flow and T500 measured values and combined with the visual inspection, the SCC mixes were classified into three performances: qualified, insufficient fluidity and segregation. By processing the videos into image sets, the deep learning models were built using image classification and target detection respectively. The models learn and train the image features of the mixes to realize the prediction of SCC performance. The results show that both image classification and target detection methods can achieve more than 98% accuracy on the validation set, which provides a reference for adjusting the mix proportion in real-time and realizing the smart production of SCC.

In order to explore the influence of water-binder ratio, fly ash, slag powder content and age on the compressive strength of full aeolian sand concrete, the compressive strength test of full aeolian sand concrete was carried out. The microscopic characterization of its physical composition was implemented in combination with XRD results. The compressive strength prediction model of full aeolian sand concrete was established by multiple linear regression. The results show that the compressive strength of full aeolian sand concrete increases first and then decreases with the increase of water-binder ratio. When the water-binder ratio is 0.4, the compressive strength is the largest. The growth effect of fly ash on compressive strength of aeolian sand concrete is not as significant as that of slag powder. The incorporation of fly ash and slag powder is easier to convert AFt into AFm. The established compressive strength prediction model has high accuracy and is suitable for sand concrete. The research results can provide theoretical basis and technical support for the engineering application of full aeolian sand concrete.

Based on the chloride ion diffusion model and aggregate gradation theory, the mesoscopic model of recycled concrete random polygonal aggregate was constructed using PYTHON and COMSOL. The validity of the model was verified by the existing experimental results. The calculation and analysis of the chloride ion erosion resistance of recycled concrete under different working conditions such as the diffusivity of new and old mortar, the thickness of old mortar and the replacement ratio of recycled aggregate was carried out. And then the diffusion law of chloride ion in recycled concrete and the influence law of critical factors on the chloride ion erosion resistance were studied. The results show that the simulation results are close to the experimental values, and the method can better simulate the diffusion of chloride ions in recycled concrete. The relationship curve between chloride concentration and depth shows discontinuous characteristics. With the increase of diffusion coefficient of new and old mortar, the chloride ion content increases gradually. The chloride ion erosion resistance of recycled concrete decreases with the increase of the thickness of old mortar and the replacement ratio of recycled aggregate.

To deal with the problems such as grouting pipe blocking and uneven diffusion of grout-enriched roller compacted concrete, the rheology, fluidity, stability, strength and time-varying properties of slurry containing micro-silica powder were studied. The entropy weight ideal point method was used to determine the optimal mix proportion by considering the working characteristics of the slurry and economic cost. The results show that adding micro-silica powder can reduce the bleeding rate and improve the compressive strength. When W/B=0.4, micro-silica powder reduces the yield stress and fluidity, and increases the plastic viscosity. When W/B =0.5-0.7, the yield stress and plastic viscosity increase with the addition of micro-silica powder. The rheology of slurry is related to the thickness of water film. With the increase of water-binder ratio, the effect of micro-silica powder on slurry’s performance gradually weakens. The yield stress increases linearly with time, and the plastic viscosity increases exponentially with time. Based on entropy weight ideal point method, the optimal mixture ratio of different schemes with fixed water-binder ratio can be obtained.

Conventional methods such as deformation monitoring, laser scanning and ground-based radar have certain limitations in the scene of high slope near the dam of hydropower station, so it is difficult to find the hidden dangers of high slope disasters near the dam in time and early-warning slope accidents. Taking a hydropower station in Jinsha River Basin as the research object, this paper proposes a high slope displacement detection method based on the UAV proximity photography, which mainly includes the UAV proximity photography data acquisition method for accurate path planning, generation of the SFM-MVS 3D model and point cloud model, and point cloud comparison algorithm based on adjacent 3D grid plane. Data acquisition, accuracy analysis and displacement comparison are carried out in the study area. The results show that the accuracy of this method in both horizontal and vertical directions reaches millimeter level, which can meet the needs of large-scale and high-precision displacement detection of high slope near the dam, and has strong scientific research and engineering practical value.

Fissure distribution has a significant effect on mechanical properties and damage failure of layered rock mass with complex fissures. Based on the uniaxial compression test and DIC technique, the influence of fissure location and fissure angle on the mechanical properties and failure of the composite fissure rock sample composed of sandstone-like and martial-like rocks was analyzed. The results show that the mechanical properties of composite fissure rock samples increase with the change of fissure location from sandstone, interface and marble and the increase of fissure angle. Influence of fissure location on rock sample failure: When the fissure is in marble, the initial crack is easy to be the far-field crack in sandstone, and the surface spalling occurs in both sandstone and marble, but the failure is more obvious in sandstone, is prone to "H-shaped failure". When the fissure is at the interface and sandstone, it is easy to produce wing crack and anti-wing crack at the crack tip of sandstone. Exfoliation occurs only in sandstone, "1γ shape failure" and "y shape failure" are easy to occur, respectively. At the same time, the stress-strain levels σ and ε corresponding to the initial crack generation at the same fissure angle increase with the change of fissure position from sandstone, sandstone to marble and marble. Influence of fissure angle on rock sample failure: When α=90°, the tip is not easy to crack, and when α=45°, the tip is easy to crack. When the fissure location is the same, the σ and ε of α=90° are the largest, while the σ and ε of α=0° and α=45°are the smallest. "H-shaped failure" occurs when α=0° and "y-shaped failure" occurs when α=90°. The research results are instructive for practical engineering construction and design.

In order to study the mechanical properties of rocks with prefabricated fissures, rock specimens with intermittent fissures at different angles were prepared. Uniaxial compression test was carried out on the specimens with fissures using uniaxial compression test equipment. It is found that the uniaxial compressive strength of 40° intermittent fissures is the largest, followed by that of 60°and 20°. The PFC2D was used to simulate the test process. The change law of microcrack and stress in the test process was analyzed. It is found that the strength of rock bridge has an important impact on the uniaxial compressive strength of the specimen. Through comparison, the change law of stress-strain curve of numerical simulation is basically consistent with that of physical test.

In order to study the seepage characteristics evolution of rock mass in the water level-fluctuating zone under condition of water-rock interaction, the dolomite in the reservoir area of Wudongde Hydropower Station was selected as the research object in this paper. The variation law of fracture seepage characteristics was obtained through the single fracture seepage test. With the help of SEM and 3D surface contour scanning technology, the variation law of fracture surface microstructure and surface morphological characteristics was studied, and the influence mechanism of fracture seepage characteristics evolution law was discussed. The results show that in the process of water-rock interaction, when the seepage pressure is constant, the seepage decreases exponentially with the increase of confining pressure; When the confining pressure is constant, the seepage increases linearly with the increase of seepage pressure; With the increase of water-rock interaction period, the seepage of fractures decreases rapidly at first and then slowly, and then increases slowly and tends to be stable. The water-rock interaction softens and dissolves the minerals at a certain depth of the fracture surface, and changes the micropore structure and surface morphological characteristics. Under action of confining pressure, the fracture surface is more closed. The further reduction of effective crack width is the main reason for the decrease of fracture seepage.

In order to solve the sliding failure problem caused by the wet expansion and dry shrinkage of expansive soil in the North Xinjiang water supply project, lime, cement and sand and gravel were used as the main curing materials. Through unconfined compressive strength test, direct shear test, compression test and SEM test, the influence of test dosage on the mechanical properties of improved expansive soil and the formation mechanism of microstructure strength under different improvement methods were studied by combining macro and micro. The test results show that with the continuous increase of the amount of lime and sand gravel, the soil strength increases steadily, while the peak value of cement improved soil appears when the amount of lime and sand gravel is about 7%. For lime and sand gravel, when the amount of lime and sand gravel is about 6% and 30% respectively, the overall compressibility of the improved soil is low, the cohesion is large, and the shear and compressive strength is high, which can meet the requirements of engineering application. The SEM analysis of lime and cement stabilized soil with the best mix ratio shows that a large number of curly flake hydrated gel materials are generated, which significantly reduces the pores compared with the original expansive soil, and the aggregates are closely cemented. From the macro mechanical properties, the mechanical properties and stability of the solidified soil are greatly improved.

It is of great significance to explore the variation law of soil thermal conductivity for fields of ground source heat pump systems and soil heat storage. The thermal conductivity variation law of loess and sandy soils with different dry densities and different saturations was investigated by TEMPOS thermal performance analyzer. The results show that saturation and dry density both have significant effects on the thermal conductivity of soil. The thermal conductivity of loess and sandy soil shows an overall increasing trend with the increase of saturation, but there is an obvious difference in the change pattern of thermal conductivity of loess and sandy soil. The thermal conductivity of loess and sandy soil increases with the increase of dry density, but the change range of loess soil is smaller than that of sandy soil. At the same time, 16 prediction models are evaluated based on the experimental data and the results show that the CCM model performs the best.

The determination of water conservancy project construction scheme is one of the most important decisions during the whole project construction period, which has an important impact on the progress and cost of the project. Considering the influence of main construction machinery and team configuration on construction period and cost, this paper established SVR model to simulate different construction schemes and corresponding construction period and cost data, and used multi-objective genetic algorithm to optimize construction schemes. Taking a box culvert project of South-to-North Water Transfer as an example, optimization model was established considering both construction period and cost. The optimization of project construction scheme was realized, and the applicability and accuracy of the model and method were verified.

As the time goes by, the seal of the bearing oil tank cover of the hydropower station is gradually worn, the gap between dynamic and static increases, and the oil mist escapes seriously. In order to explore the influence of wear clearance and unit speed on oil mist leakage in oil tank seal, a geometric model of thrust bearing oil tank seal of generator was established. Using SST κ-ω turbulence model, steady state numerical simulation was carried out for oil mist leakage at different clearances (0.2 mm-2 mm) and rotating speeds (100 r/min-500 r/min). It is found that the influence of clearance value on oil mist leakage is much higher than that of rotational speed. With the increase of clearance, the throttling effect of sealing teeth is weakened, the sealing inlet pressure is reduced, and the oil mist leakage at the top of the tank cover is aggravated. The inlet and outlet velocity increases with the increase of wear clearance value. When the clearance value increases from 0.2 mm to 2 mm, the inlet velocity increases from 20 m/s to 113 m/s, the outlet speed increases from 76 m/s to 144 m/s, the leakage volume increases from 0.034 4 kg/s to 0.053 8 kg/s. The research can provide a theoretical basis for the optimization of sealing structure, the formulation of power station operation strategy, and the judgment of sealing performance.

In previous researches on intelligent fault diagnosis methods of the hydroelectric generating unit, the subjectivity of the artificial selection of the fault classification characteristics and the limitations of small sample data have important impacts on the accuracy of fault diagnosis results. To solve this problem, a CNN-SVM method for the fault diagnosis of the hydroelectric generating unit was proposed by combining with the feature extraction advantages of convolutional neural network (CNN) and the excellent ability of support vector machine (SVM) in processing small sample. In this method, the time-domain diagram of the vibration signal of the hydroelectric generating unit was used as the model input, and the CNN method was employed to extract the signal features. Then, the extracted feature vector was input to the SVM method to realize the final fault diagnosis of the unit. Finally, the advantages of the diagnosis method proposed in this paper were verified through a specific example analysis.

At present, most of the domestic parallel pump groups adopt a single-objective control model, and only pay attention to the energy efficiency optimization of operating conditions and operating costs in the process of use, and cannot adjust the operation strategy under the real-time working conditions of the pump group according to the comprehensive energy efficiency state of the pump group in the whole life cycle. A multi-objective pump group energy efficiency optimization control model can be independently adjusted according to the energy efficiency state of the current pump set in the whole life cycle. The weight coefficients of three objective functions can be autonomously adjusted, which improves the energy efficiency of the pump set throughout its life cycle and extends the life of the pump set. The objective function was determined by the ideal point value and distance deviation method. The multi-objective ideal point model was solved by LINGO. The optimal solution with the highest total system efficiency, the lowest pump group specific energy consumption and the highest system reliability was obtained. Experimental results show that the improved multi-objective ideal point model can adjust the target weight combination according to the real-time state of the pump group, so as to adjust the real-time control strategy of the pump group.

Accurate load forecasting is of great significance for improving the level of grid planning and accurately guiding investment. In view of the shortcoming of over-fitting in the combined forecasting model of empirical risk minimization, a combined forecasting model based on social learning multi-objective particle swarm optimization algorithm was proposed in term of partial least squares regression model, support vector regression model and grey prediction GM (1, 1) model. The uncertainty function information entropy of weight was introduced to represent the expected risk, and the empirical risk and expected risk were comprehensively considered in the model. The simulation results show that the proposed method has higher prediction accuracy than the single forecasting model and the other two combined forecasting models, and the social learning multi-objective particle swarm optimization algorithm has stronger global search ability and optimization performance.