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.

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.

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.

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.

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.

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.

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 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.

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.

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.