The structure of fishway is the major factor that fish migrates successfully. The impact of pier head structure and horizontal interval of baffles on the hydraulic characteristics of a vertical slot fishway pool were researched. Twelve different working conditions were composed of two factors, namely, the diversion angle of pier head and the relative position of baffles. The RNG κ-ε turbulence model was used to simulate the hydraulic characteristics of fishway. The results indicate that the influence of pier head structure on hydraulic characteristics is mainly reflected on velocity and turbulent energy, and the smaller the diversion Angle, the smaller the velocity and turbulent energy are. The distance between flow deflector and baffler plate changed the mainstream flow pattern and area size, and then affected the distribution of flow velocity. When the relative position of b₀/L=0.15 or so, the flow pattern in the pool was reasonable, which met the basic requirements of fish migration.

In view of the problem of inconsistency and lack of real-time synchronization of data in each security zone with the increase of specialty system, this paper analyzed the cross-regional synchronization requirements of the Yalong River integrated hydropower management and control platform system, and proposed a simple, stable and reliable cross-regional synchronization system architecture based on the characteristics of unified construction and deployment of all specialty system based on the integrated platform. Real-time synchronization was achieved by intercepting the write operation context through the platform service gateway. The design realized the unified communication management and synchronization optimization of the professional data of the Yalong River integrated control platform system, effectively improved the performance and reliability of the system, and adapted to the future development of integrated system business of water, electric power and new energy dispatch.

To investigate the spatial and temporal variation of terrestrial water storage in the Yellow River Basin, the inversion of terrestrial water storage in the Yellow River Basin was performed based on the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) gravity satellite data from 2003 to 2020. Besides, the Variable Infiltration Capacity (VIC) hydrological model was used to simulate the soil water changes. The groundwater storage changes between 2003 and 2014 were calculated through the water balance equation. The results show that the overall terrestrial water storage in the Yellow River Basin is in deficit during the study period, with a significant decreasing trend temporally. Spatially, the water storage is reducing from the river source to the downstream. The inversion results show that the spatial and temporal variation of terrestrial water storage in the Yellow River basin is highly correlated with the topography, climate and human activities. The results can provide a scientific basis for water resources planning and allocation in the Yellow River Basin.

Taking the self- and cross-correlation of the multi-station streamflow series of the main and tributary of the basin as the starting point, a multi-site flood series simulation method based on the conditional resampling theory was proposed, and simulate the flood series of Pingshan, Cuntan and Yichang station on the main stream of Changjiang River. The simulation results were compared with the results of the multi-station seasonal autoregressive model (MSAR) for verification and analysis. The results show that compared with the traditional model, the proposed method can not only satisfy the basic statistical characteristics of the runoff series and the higher-order self- and cross-correlation structures of the series, but also further consider the historical extreme flood characteristic, and could generate multi-station simulated flood scenarios with different design frequency.

With the continuous development of the city, influenced by climate change and human activities, the runoff of urban water system has changed greatly. In order to further research the runoff trend and its main influencing factors brought by urbanization, the application of the comparison of slope change ratio in hydrological change analysis was further innovated, and the contribution rate of underlying surface to runoff change was separated from human activities. Taking Zhengzhou city as an example, combined with Mann-Kendall test method, the contribution rate of climate change factors, underlying surface factors and other human activities to runoff change was calculated. The results indicate that the measured runoff flow showed an upward trend from 1980 to 2019, and a sudden change occurred in 2008. In the impact analysis of runoff, the change of underlying surface and other human activities are the main influencing factors, and their contribution rates are 69.76% and 56.19%. According to the analysis of the main influencing factors, the main reasons are as follows: The hardening of the underlying surface increases runoff yield and flow concentration, and the population increases and the emissions increase.

Urban water bodies play a vital role in maintaining the urban environment and development. In order to solve the problem of low transparency of its water body, taking Yaojiang River as the research object, the effects of solar radiation, turbidity, suspended solids concentration and particle size on water transparency were analyzed by means of comparative ratio, Pearson correlation analysis, and curve fitting calculation. The results show that the light intensity, solar elevation angle and azimuth angle affect the transparency monitoring. The stronger the light is, the greater the monitoring result of transparency is. Transparency (SD) is negatively correlated with turbidity (TUB) and suspended solids concentration (SS). Pearson correlation coefficients are -0.880, -0.570. After monitoring and calculation, the median particle size (d_50%) of Yaojiang River is between 15.5 and 61.3 μm. Filtration through a filter with a pore size of 10 μm can control the turbidity of the water body within 9.7 NTU and the concentration of suspended solids within 13.4 mg/L. The transparency of the Yaojiang River can reach 80 cm, which is the minimum requirement to maintain a normal aquatic environment.

The lakes on Tibetan Plateau are expanding continuously, and the frequency and intensity of natural disasters (debris flow, glacial lake outburst) are increasing, which brings a series of challenges to water resources management, water disaster prevention and sustainable development in Tibetan Plateau and its downstream areas. Taking Yigong Lake as the research object, this paper establishes Tableland NDWI (TNDWI) based on 1 101 remote sensing images. Then the water surface morphology of Yigong Lake from 1986 to 2020 is reconstructed to analyze evalution process of historical water surface morphology in lake. The results show that the user accuracy of the TNDWI for the classification of plateau water bodies is higher than 96.70%, the overall accuracy is higher than 98.75%, and the Kappa coefficient is between 0.972 and 0.992, and the classification accuracy and consistency are better than the tranditional NDWI; The 2000 Yigong landslide has a significant impact on the evolution process of water surface morphology of Yigong Lake; Water surface area after dam-break reduces from 14.44±2.70 km² to 10.99±1.94 km²(P <0.001). Mann-Kendall mutation test results show that the change trend of water surface morphology has a mutation in 2000 (except in dry season); Morlet wavelet periodic analysis results show that the periodic oscillation law of lake area has gradually weakened since 2000. This study overcomes the lack of monitoring data of high altitude barrier lake, providing data basis for the ecological restoration and comprehensive treatment project of Yigong Lake as well as new idea for the quantitative study of the ecological environment in the region.

In order to study the damage behavior of fiber reinforced concrete at high temperature, the acoustic characteristics of hybrid fiber reinforced concrete (PVA fiber and basalt fiber) at different temperatures were tested, and the mechanism was explained from the microscopic level by combining the results of the SEM. The results show that with the rising of temperature, the degree of ultrasonic waveform distortion is more significant, and the attenuation of waveform amplitude is gradually intensified; The incorporation of fiber or the increase of temperature will reduce the amplitude of the dominant frequency of the waveform and increase the energy dissipation caused by the ultrasonic penetration of the specimen. At high temperature, after PVA fiber is melted, a large number of pores remain and gradually form connecting pores, which promote the release of pore steam pressure and alleviate high-temperature damage, while basalt fiber continues to play a bridging effect to inhibit the continuous development of high-temperature cracks.

At present, the existing speed relays on the market only collect single signal source, poor anti-interference. It is easy to disorder the signal of the speed node output caused by measurement signal distortion and measuring channel fault. In order to improve the reliability and accuracy of the speed relay, two channels of residual voltage signals and two channels of sprocket speed measurement signals were respectively connected. Then the dual-probe tooth sequential speed measurement method was combined with the logic of selecting one out of three speed signals. The judgment method selected one speed signal as the main signal. In the signal output process of the rotational speed node, the limiting average filtering method and the method of retrieval interference output blocking were applied to eliminate the distortion in the signal output process. Through the simulation test bench test and the application in the actual generator set, the anti-interference ability of the acquisition signal loop, the signal measurement accuracy, and the reliability of the output action of the speed node have been significantly improved.

At present, in the region of China Southern Power Grid, there is a case that the actual load adjustment amount of primary frequency control of some hydropower units cannot reach the theoretical value under certain working conditions, resulting in the assessment of primary frequency regulation. This paper processed the original operation data of a unit, and calculated the actual load adjustment amount and actual adjustment rate of primary frequency regulation. Compared with the theoretical value, the qualified working condition area of the primary frequency regulation process was found out. The characteristic operating points were selected in the qualified working condition area, and the multi-objective particle swarm optimization algorithm based on Pareto optimization criterion was used to find the optimal PID parameters. The simulation results show that the optimized PID parameters can make the unit have better primary frequency regulation performance index than the actual parameters of the governor.