Based on the runoff data of Buha River Basin and Shaliu River Basin in Qinghai Lake Basin, the annual base-flow index was obtained by using the filter smoothing minimum method. The temporal and spatial variation of precipitation and the evolution law of base flow in this basin were analyzed by TFPW-MK method, and the influencing factors of base flow were analyzed. The results show that the base-flow index of Buha River Basin first increases, then decreases and increases, reaching the maximum in May and the minimum in August; The base flow index of Shaliu River Basin fluctuates and reaches the minimum in April. The annual average runoff in the Buha River Basin and the Shaliu River Basin showed a significant increasing trend, and both the annual average base flow and base flow index showed an insignificant increasing trend; The base flow inclination rate of the Buha River Basin is twice that of the Shaliu River Basin. The base flow sequence of the Buha River Basin and the Shaliu River Basin is greatly affected by precipitation, flow, drought index and evaporation, and the Shaliu River Basin is more significantly affected by evaporation.

In view of the short water hammer control distance of a single air valve in long-distance and low lift water delivery projects, which can not effectively suppress the vacuum in the pipe, a new water hammer control scheme of combined protection of air-valve surge tank and air valve was proposed. Taking a practical project as an example, a comparative analysis of the hydraulic transient process was carried out for the air valve protection and the combined protection scheme of air-valve surge tank and air valve. The results show that the water column separation occurs in the main pipe when the air valve is used for protection, and a large impact water hammer is caused by the rapid exhaust. The combined protection scheme of air-valve surge tank and air valve can not only effectively suppress the vacuum in the main pipe, but also effectively alleviate the impact water hammer caused by exhaust. It is an economic and effective water hammer protection scheme, and can provide a reference for the water hammer protection of other long-distance and low-lift water delivery projects.

In order to study the surge wave characteristics of pumped storage power station with upstream and downstream surge chambers under small fluctuations, the mathematical model of small fluctuations in a pumped storage power station with this type of arrangement was derived based on the state-space method. The time-domain process of surge wave in the upstream and downstream surge chambers was solved by numerical simulation. The frequency-domain process of surge wave in the upstream and downstream surge chambers was obtained by the fast Fourier transform (FFT). Without considering the hydraulic coupling between the speed regulating system and the surge chamber system, the transfer function between the pressure pipeline flow and the water level of the surge chamber was established to obtain the amplitude-frequency characteristics of the surge chamber systems. The results show that the input signal frequency corresponding to the maximum amplitude of the surge wave in the upstream and downstream surge chambers is similar to the natural frequency of the surge chamber system, and the surge wave oscillation frequency in the surge chamber corresponds to the tail wave oscillation frequency of the unit speed. The surge wave characteristics of the surge chamber are closely related to the area of the surge chamber and the head loss coefficient of the water delivery tunnel. Increasing the area of two surge chambers can reduce the frequency and amplitude of surge wave in the upstream and downstream surge chambers, and enhance the stability of the system. The variation of head loss coefficient of the tunnel has no impact on the oscillation frequency of surge wave in the upstream and downstream surge chambers, but has a great impact on surge wave amplitude in the upstream and downstream surge chambers. The larger the head loss coefficient is, the smaller surge amplitude is, the system stability is better.

Long distance and concealment of underground cable in hydropower station result in difficulties in cable fault location. Due to the simple wiring, the impulse high-voltage flashover method is commonly used to locate cable faults, which needs technicians with rich waveform analysis experience to locate fault accurately. For the above situation, by studying the fault positioning principle and waveform analysis method of impact high voltage flashover, a cable fault location technology based on traveling wave cross-correlation method was proposed. The simulation analysis results show that the proposed method can effectively realize automatic cable fault location. Finally, the analysis steps and procedures of power cable fault location has been practiced in Houziyan Power Generation in Dadu River and realized high-precision positioning of 10 kV cable fault point, which reduced the cable fault locating workload and working hours while improving the efficiency of cable fault location.

When the diffusion angle of each side of the wing wall in the gate is 12°, the horizontal distribution of outlet velocity of single-stage stilling basin is easy to be uneven in the medium and low water level period. To solve this problem, based on the physical model test, the law of horizontal distribution of outlet velocity of two-stage stilling basin was studied. The results show that with the decrease of downstream water level, the outlet velocity at the left and right banks of the second stage stilling basin changes in four stages: decrease- increase-decrease-increase, and the initial water level and water level range of each stage were closely related to the Fr. The smaller the incoming flow Fr is, the stronger the horizontal diffusion ability of hydraulic jump in the second stage stilling basin is, and it will be less disturbed by the backflow on both sides of the first stage stilling basin. The range of water level in the second stage will be larger, and it is more suitable for the medium and low water levels. The closer the downstream water level is to the end water level of the second stage, the greater the outlet velocity at both sides of the second stage stilling basin is, and the horizontal distribution of outlet velocity is more uniform. When the incoming flow Fr is the same, the regulating effect of the second stage stilling basin is more significant at low water level, and the energy dissipation rate is greater. The results can be used as a reference for the design of energy dissipation facilities under the gate and the operation management of the gate.

The vertical slit fishway has the capacity to better cope with the fluctuation of water level in both upper and lower sections and favorable water flow conditions. Three schemes were designed for the shape of the fishway tank chamber of a certain project fishway. The physical models verified with a 1∶5 scales were used to investigate the impact of the tank chamber's structure on the flow pattern, maximum flow velocity, and hydraulic properties of mainstream region under different size and type of baffle and guide plates. This was done through numerical simulation calculation. They performed a test of the physical model on the optimal shape with scale of 1∶5. The physical model of the overall with scale 1∶20 was used to analyze the maximum velocity along the water depth and the vertical slit, and the diversion flow of the fishway under different water depth conditions was proposed, providing reference and reference for similar projects.

In order to evaluate the water use efficiency of the central Yunnan urban agglomeration accurately, 14 indicators were selected from five aspects of comprehensive, industrial, agricultural, living and ecological water use, and the evaluation index system was constructed. The subjective weights were obtained by analytic hierarchy process. The entropy weight method was used to determine objective weights. The game theory method was adopted to get the combination weight. The TOPSIS evaluation model was established to calculate the relative closeness degree of water use efficiency and the closeness degree of each criterion layer in central Yunnan urban agglomeration from 2011 to 2020, and the national average data was added to the evaluation sample as the criterion for judging the results. The results show that in terms of spatial distribution, Kunming has the highest water use efficiency, followed by Qujing and Yuxi, both of which are at a good level, and Honghe and Chuxiong have the lowest water use efficiency, both of which are lower than the national average water use efficiency, at a poor level; In terms of time series, except for Qujing City, the overall water use efficiency shows an upward trend. Qujing City shows a downward trend before 2016 and slowly recovers in 2016. By analyzing the causes of the changes, this paper put forward the shortcomings of water use efficiency in each city, which can provide reference for improving water use structure and water use efficiency in central Yunnan urban agglomeration.

In order to realize the sustainable utilization and maintain the healthy development of river and reservoir ecosystem, this paper applied energy value analysis to reservoir ecological operation for discussing the energy optimal operation of reservoir ecological service value. With the objective of maximizing the service energy of Manwan Reservoir and the constraints of ecological water demand and social economic water consumption, an optimal operation model of reservoir ecosystem service energy was established, and the ant colony algorithm was used to solve the model. The results show that the total service energy of Manwan Reservoir is 2.10×10²² sej in high flow year, 1.79×10²² sej in normal year, 1.58×10²² sej in dry year. Main service values are ecological regulation, water supply and ecological support, material production followed, cultural entertainment is the minimum. The results have practical value and important significance for maintaining the healthy development of the Lancang River basin, especially for the ecosystem of the Manwan Reservoir Region.

In order to research the growth adaptability and engineering applicability plants in the floodplain ecological restoration area in the lower reaches of the Three Gorges dam area under flooded environment, four kinds of shrub plants such as distylium chinense, myricaria laxiflora, salix variegata and rosa sp were planted and observed in the floodplain area at the same water level in the lower reaches of the Three Gorges dam area. Four shrub plants experienced a certain degree of flooding period. The results show that the survival rates of the four shrub plants were different under flooding conditions, and the plant preservation rates from high to low were as follows: salix variegata, distylium chinense, myricaria laxiflora and rosa sp. The morphological changes, plant height growth and recovery growth were observed. Among them, salix variegata, distylium chinense and myricaria laxiflora showed better flooding adaptability under flooding stress. The applicability of ecological restoration engineering of 4 Shrub plants was evaluated by weighted scoring method. The scores from high to low are distylium chinense, myricaria laxiflora, rosa sp and myricaria laxiflora. It is determined that distylium chinense can be used as the main shrub plant in the floodplain ecological restoration project.

In order to alleviate the waste of resources caused by the leakage of urban water supply networks, taking predictive classification as the basic idea, the monitoring data after wavelet noise reduction processing was used in the prediction model of PSO seeking least squares support vector machine algorithm, and the prediction model was trained and evaluated, then combined with the model prediction error distribution law, the estimation method of threshold value and leakage volume was introduced for leakage detection. The results show that the average error between the model prediction and the actual water volume is low, the stability is high, and the combination of the prediction-threshold classification method can detect sudden leakage in a timely manner and estimate the leakage volume relatively accurately.