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.

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.

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.

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.

In order to clarify the hydraulic performance of the submersible tubular pump device in Yangzhou Gate Pumping Station, the internal flow and hydraulic performance of the submersible tubular pump device were analyzed by numerical simulation combined with physical model test. The influence of the front and rear bulbs body on the energy performance of the pump device was compared and analyzed through the comprehensive characteristic index C.P.I, and the scheme of the submersible tubular pump device with the rear bulb body was optimized. The maximum efficiency of the submersible tubular pump device with the rear bulb body is 78.86 %, the flow rate is 314.86 L/s, the lift is 3.594 m, and the blade placement angle is +2°. When the blade angle is -4°, the runway speed of the prototype pump device is 295.19 r/min, which is 1.75 times the rated speed of the prototype pump device. The streamline of straight pipe inlet is smooth under each flow rate conditions, the local area of guide vane appears backflow and the spiral flow inside straight outlet conduit is obvious under small flow rate conditions. With the increase of flow rate, the proportion of hydraulic loss of bulb body and outlet conduit decreases firstly and then increases, and the proportion of hydraulic loss of bulb body and outlet conduit in the whole flow conduits of pump device is the largest. The research results can provide reference for pumping station engineering.

To meet the fault prediction needs of hydro-generator units in the context of big data, combining the characteristics of the attention mechanism with good feature extraction ability and the advantages of model robustness for multi-sensor information driving, this paper proposed a fault prediction system of hydro-generating units based on the attention mechanism and multi-sensor information driving. The system was applied to on-line monitoring of unit ^#8 in August for a hydropower station in Hunan Province. The actual operation results show that the system can effectively predict the vibration trend of the hydro-generator set and realize the intelligent prediction of the hydro-generator.

To fully consider the temporal volatility and randomness of runoff and associated source & load in the optimal dispatch of hydropower and reduce spillage water, a probabilistic prediction method of annual scenarios for hydropower runoff and associated source & load was proposed to simulate the typical annual temporal scenarios of average daily runoff and associated source & load and their probability of occurrence. Several typical ten-day scenarios were generated by clustering with a self-organization mapping net (SOM). Then a ten-day scenario simulation model was built based on a Markov-chain probability matrix, a multi-scenario conditional probability matrix, and the similarity principle— "the closer historical year, the larger weight." It ensures that the simulated scenarios accurately fit the statistical characteristics of actual data (randomness, seasonality, and conditional correlation) for intra-year and reflect the trend evolution year-to-year. Combined with the fluctuation checks, annual temporal scenarios were simulated by the Monte Carlo method. Finally, the k-means scenario reduction was used to obtain typical annual temporal scenarios and their probability of occurrence. The results of an actual hydropower example show that the proposed method has the advantages of high accuracy, strong adaptability, and comprehensive prediction information.

Dynamic strength is an important parameter for dam stability and safety analysis, which is of great significance to engineering design. Variable amplitude cyclic loading and unloading test was carried out to explore the effect of different confining pressure and cement content on the dynamic stress-strain relationship of cemented sand gravel (CSG) material by large dynamic triaxial instrument. Based on the Mohr Coulomb strength criterion, the evolution law of dynamic strength parameters of CSG materials during plastic deformation was studied by taking the dynamic strain as the plastic internal variable. The results show that the dynamic cohesion and dynamic internal friction angle increase with the increase of cement content. As the dynamic strain increases, the dynamic cohesion decreases rapidly, the dynamic internal friction angle increases, and the friction force generated by the shear slip between the aggregates dominates. When the peak dynamic stress is reached, the effective stress surface between aggregates decreases obviously, the dynamic cohesion decreases gently, the dynamic internal friction angle decreases with a certain hysteresis. The law of dynamic cohesion with dynamic strain conforms to the power function relationship. The law of dynamic internal friction angle and dynamic strain change conforms to the quadratic function relationship. The research results can provide a theoretical reference for the optimization of seismic design of CSG dam.

Goss error detecting method of monitored dam deformation data is researched based on the fully convolutional neural networks (FCN). Firstly, the method of representation learning of artificially labeled data sets by FCN model was proposed to simulate engineers’ experience. Secondly, the FCN model for gross error detection was built and artificially labeled data sets were used for model training. Finally, the trained FCN model was used for gross error detecting of monitored deformation data of a gravity dam. The results show that the gross error in monitored dam deformation data can be accurately obtained by the proposed method, which can improve efficiency of dam safety management.

As a large steel structure in the open environment, the miter gate will form a non-uniform time-varying temperature field under the solar radiation, resulting in complex temperature effect on the structure. If not paid attention to the project, it may lead to safety problems such as weld cracking and structure instability. The temperature field of the structure was analyzed by changing the surface coating and using finite element software. The results show that under solar radiation, the gate panel and the top beam form a multi-temperature area array distribution of temperature field, and the beam system temperature distribution is relatively uniform. The surface coating has great influence on the temperature field of the gate. The coating with low radiation absorption rate can reduce the temperature rise of the gate components, and the maximum temperature can be reduced by about 25%. The distribution of temperature field is greatly improved, which can effectively prevent local stress concentration or excessive deformation in the stress field and deformation field of the gate.