To improve the accuracy of multi-step prediction of daily runoff， reduce the computational scale of the model， and enhance the performance of the Coati Optimization Algorithm （COA） and Hybrid Kernel Extreme Learning Machine （HKELM）， a Multi Pole Wavelet Packet Transform （MWPT） - Improved COA（ICOA） algorithm - HKELM daily runoff time series prediction model is proposed. Firstly， using MWPT， the daily runoff time series data is decomposed into 1 low-frequency component and 2 high-frequency components， and a HKELM is constructed by combining local Gaussian radial basis function kernel and global polynomial kernel function； Secondly， the principle of COA algorithm is briefly introduced， and by improving COA based on strategies such as Circle mapping， we propose the ICOA algorithm. The ICOA algorithm is simulated and verified through 8 typical functions， and is compared with the basic COA algorithm， Whale Optimization Algorithm （WOA）， and Grey Wolf Optimization Algorithm （GWO） to verify the optimization performance of the ICOA algorithm； Finally， using ICOA to optimize HKELM hyperparameters （regularization parameters， kernel parameters， weight coefficients）， a MWPT-ICOA-HKELM model is established， and MWPT-COA-HKELM， MWPT-WOA-HKELM， MWPT-GWO-HKELM， Wavelet Packet Transform （WPT） - ICOA-HKELM， Wavelet Transform （WT） - ICOA-HKELM， and MWPT-ICOA-BP models are compared and analyzed. The models are validated through multi-step prediction examples of daily runoff time series from Jingdong and Baobian hydrological stations in Yunnan Province from 2016 to 2020. The results show that： ① ICOA has a good improvement effect， and the simulation accuracy is better than COA， WOA， and GWO algorithms. ② The MWPT-ICOA-HKELM model has better prediction performance than other comparative models， with the best single step prediction performance for instances， better results with 3 and 5 steps ahead， and worse results with 7 steps ahead. The prediction accuracy decreases with the increase of prediction step size. ③ Optimizing HKELM hyperparameters using ICOA can significantly improve HKELM prediction performance， and the hyperparameter optimization effect is better than COA， WOA， and GWO algorithms.

Automated precise identification of rivers in high-resolution remote sensing images holds significant importance and research value in river and lake environmental monitoring， as well as watershed change studies. However， due to the relatively small area occupied by rivers in the images， it can lead to an imbalance between positive and negative samples in the dataset. Additionally， the morphological variability and complex scale transformations inherent in rivers contribute to challenges in river identification， resulting in issues such as discontinuous boundaries and grid effects. In response to these challenges， this paper proposes a cross-scale river precise identification method with fusion of global multilevel features. The method can be divided into three main parts. Firstly， we construct a multi-feature river dataset by selecting globally distinctive meandering and braided rivers to enhance data diversity. Secondly， we construct the R-Seg model， utilizing the lightweight semantic segmentation model Segformer as the backbone network. We design the Global and Adaptive Scale Pyramid Pooling （GASPP） module for extracting multi-scale features. This module， coupled with Transformers， facilitates the extraction of multi-scale features， enabling the model to capture contextual information in river images， reduce information loss， and amplify global dimension interaction features. Lastly， we propose a cross-scale river image prediction method based on mask-weighted voting. By employing sliding window cropping on large-scale river images， we obtain sub-prediction results by multiplying each unit prediction block with a specific mask weight. These results are then sequentially concatenated through overlapping voting， achieving precise identification of river images at different scales. The experiments demonstrate that， in the constructed multi-feature dataset encompassing meandering and braided rivers， a comparative analysis with other methods reveals the following： qualitatively， the overall structure of the R-Seg network ensures high identification accuracy for main rivers and effectively mitigates interruptions in smaller river flows， smoothing river boundaries with good robustness for 500×500 small-scale river image identification. Moreover， the use of mask-weighted voting method significantly reduces the edge loss problem caused by grid effects in unit blocks， making full use of unit block prediction results， improving river prediction accuracy for larger scenes， and achieving accurate identification of river images of different scales. From a quantitative perspective， the method achieves an overall accuracy of 99.49% with optimal performance across various accuracy evaluation metrics. Also， the single-image identification time is less than 1 second， meeting the efficiency requirements of most practical applications. Furthermore， the mask-weighted voting strategy exhibits an overall higher river identification accuracy of approximately 0.28% to 6.93% compared to a pure overlap prediction strategy. By adjusting the overlap parameter， it is observed that accuracy and overlap are not positively correlated； an accuracy of approximately 12.5% achieves relative optimization. This approach， through the design of the R-Seg network model and the introduction of the mask-weighted voting prediction method， effectively alleviates issues such as discontinuity in river boundary recognition and grid effects. It significantly enhances the accuracy of river identification in remote sensing images across diverse scenarios， demonstrating strong robustness and visual performance. The identification outcomes hold crucial application value in geological exploration of rivers and studies on watershed changes.

Flood disaster is one of the main natural disasters in Hubei province. Conducting research on the resilience of urban flood disasters in Hubei Province can accelerate the construction of resilient cities in this region and promote the sustainable and healthy development of cities. This paper takes 17 cities in Hubei Province as the research object， selects the period from 2010 to 2021 as the research period， constructs the urban flood disaster resilience evaluation index system from three dimensions， including pressure， state and response， analyzes the spatio-temporal evolution of flood disaster resilience by applying the CRITIC-Entropy Weight Method combination weighting method， and analyzes the spatial agglomeration characteristics of flood disaster resilience by using the spatial autocorrelation method. Then the driving factors are analyzed by the geographic detector model. The results indicate that： First， during the study period， the resilience index of urban flood disasters in Hubei Province showed a wave rising trend， with an increase of 34.82%， Second， The spatial distribution of urban flood disaster resilience is mainly “high in the west and low in the east” pattern， with values decreasing outward from Wuhan City. The spatial agglomeration effect of urban flood disaster resilience is strong. Third， the spatial heterogeneity of urban flood disaster resilience is caused by multiple factors. Wherein， population exposure， terrain fluctuation， surface steepness and medical security capacity being the main driving factor. The research results can provide reference for urban flood control and disaster reduction policies.

The analysis of the effect of human activities on the drought propagation is of great significance for drought early warning， and reducing the social and economic loss. Based on the measured monthly precipitation and runoff series from 1960 to 2017 at four meteorological and hydrological stations in Panjiakou Reservoir basin， Standardized Precipitation Index （SPI） and Standardized Runoff Index （SRI） are used to characterize meteorological drought and hydrological drought in the study area. Through the method of non-stationarity test， combined with the actual situation of the basin， the abrupt change points of the runoff series are obtained. Based on the Pearson test method and Copula model， the propagation time and probabilities of meteorological drought to hydrological drought in the base period and human activity period are calculated to analyze the impact of human activities on drought propagation. The results show that the runoff series of the Panjiakou Reservoir basin show a significant decreasing trend， and the abrupt change point of the runoff sequence is around 1979. Human activities have a significant impact on hydrological drought and drought transmission in the basin. Human activities significantly increase the frequency of hydrological drought and reduce the correlation between meteorological drought and hydrological drought. Drought propagation time show seasonal differences， with shorter drought propagation time in summer and autumn than in spring and winter. Under the influence of human activities， the drought propagation time in summer is generally shortened by 1-4 months； the drought propagation time in spring， autumn and winter showed different variations， but the drought propagation time was prolonged in most sites. Under the same meteorological drought condition， the probability of triggering hydrological drought decreases with the increase of drought level. The probability of hydrological drought occurring increases with the intensification of meteorological drought， and the change of drought propagation probability presents two situations： human activities may promote or inhibit the occurrence of hydrological drought， and increase or decrease the propagation probability of drought.

Hydrological drought has seriously constrained the socio-economic development of China. Under the influence of climate change and human activities， hydrological droughts occur frequently， leading to the more prominent problem of water shortage in basins. Therefore， it is necessary to analyze the influence of different factors on hydrological droughts from a multi-factorial perspective， so as to provide a reference for drought relief in basins. To this end， the Xiangjiang and Weihe basins， which are typical basins in China with prominent water use conflicts and severe droughts， were selected as the study areas to investigate the effects of precipitation characteristics and land cover changes on hydrological droughts in the two basins. Firstly， the Pettitt mutation test and the rainfall-runoff double cumulative curve method were used to determine mutation points of streamflow in the two basins， and the hydrological drought events in the Xiangjiang and Weihe basins before and after the mutation points were identified according to standardized streamflow index. Finally， the impacts of changes in precipitation characteristics and land cover on hydrological droughts in two basins during different periods of time were analyzed based on the comparison of the random forest and linear regression methods. The results indicate that the runoff in the Xiangjiang River Basin did not change suddenly between 1982 and 2015. The precipitation characteristics are the main factors influencing hydrological drought in the Xiangjiang basin， contributing to 53.4% of hydrological drought， with precipitation amount contributing 33.25%， which is 13.1% higher than the contribution of precipitation concentration. However， changes in land cover have no significant effects on hydrological drought in this basin， with a contribution rate of only 36.6%. The streamflow of the Weihe basin experienced sudden changes in 1993 and 2003， and the main influencing factors of hydrological drought in the basin were different in different time periods. During the period of 1982-1993， the dominant factor influencing the intensity of the local hydrological drought was precipitation amount， with a contribution rate of 34.4%. The contribution of precipitation characteristics and land cover to drought was equal during 1994-2003， while changes in forest cover became the main factor influencing drought in the Weihe basin during 2004-2015， with a contribution rate of 40%. Based on the research results， water management authorities can tailor drought preparedness measures to the climatic conditions and land cover of local basins.

Water resource problems constrain the sustainable development of water-scarce cities. In recent years， Zhengzhou City has experienced rapid social and economic development， and the contradiction between its limited water resources and the rapid growth of water demand has become more and more prominent. In order to scientifically study the long-term development of Zhengzhou city's water resources carrying capacity， according to the current economic and social status of Zhengzhou city's water resources supply and demand and development， the system dynamics method （System Dynamics， abbreviated as SD） of multi-system synthesis is used to construct a SD model for the study of Zhengzhou city's water resources carrying capacity by combining four subsystems： water resources， ecology， economic and social society， and water conservancy engineering. Comparing the historical data from 2010-2019 with the simulation data of the SD method， the average errors are all less than 10%， which has high credibility and can be used to predict the future development of water resources carrying capacity in Zhengzhou city. On this basis， the dynamic simulation of water resources carrying capacity coefficients in 2020-2030 is conducted by setting four different scenarios： continuation of the status quo， pollution control and flow saving， open -source pollution control and open-source flow saving. The results show that： the water resources carrying capacity coefficients under the four scenarios in 2030 are 1.24， 1.18， 1.00， and 0.89， respectively； the water resources carrying capacity of Zhengzhou under the continuation of the status quo and the pollution control and flow saving scenarios is seriously overloaded over time， and cannot support the rapid economic and social development of Zhengzhou； the water resources carrying capacity overload of the open-source and pollution control scenarios will have a greater resistance to economic and social development； therefore， the open-source flow saving program is the best program. The water resources carrying capacity coefficient is less than 1， and there is no overloaded state in the study period， which can be beneficial to alleviate the water shortage situation in Zhengzhou City， and promote the economic and social development. Combining the advantages of the four options， we put forward suggestions and countermeasures in favor of the sustainable development of water resources in Zhengzhou City.

With the rapid development of the social economy， the impact of high-intensity human activities on the runoff process is becoming increasingly pronounced. In order to explore the influence of human activities on runoff changes in the Luo River Basin， this study， based on the analysis of the characteristics of runoff evolution in the basin， improved traditional hydrological simulation methods using the SWAT model. By incorporating the reservoir module and considering the impact of dynamic changes in land use on hydrological simulation， the improved hydrological simulation method was applied to quantitatively analyze the impacts of micro-scale human activities， such as reservoir construction and land use changes， on runoff changes. The results show： ① From 1961 to 2020， the annual runoff in the Luo River Basin exhibited a significant decreasing trend， with an average annual reduction of about 0.12 billion m³. The Pettitt mutation test revealed a significant change in runoff in 1989， leading to the division of the study period into a baseline period （1961-1988） and a human activity impact period （1989-2020）. ② The SWAT model， parameterized using a regionalized approach， effectively simulated the runoff processes in the Luo River Basin. With the inclusion of the reservoir module， the model's performance was further improved， achieving Nash-Sutcliffe efficiency coefficients （NSE） greater than 0.8 and relative errors （RE） less than 10% during both calibration and validation periods. ③ The contributions of climate change and human activities to runoff reduction were 32.9% and 67.1%， respectively， with human activities being the primary factor driving runoff changes. Among the micro-scale human factors， the construction of Gu County reservoir had the largest impact on runoff， contributing 47.9%. The contribution rate of underlying surface dynamic change to runoff reduction is -3.0%. Other human activities， such as small reservoirs， rubber dams， earth dams， and canal systems， contributed 22.2% to runoff reduction. The findings of this study provide a scientific basis for the rational development and utilization of water resources in the Luo River Basin.

Exploring the spatiotemporal changes in crop water requirements and irrigation water requirements under the background of global climate change is of vital importance for adjusting crop planting structures， determining agricultural irrigation quotas， and managing water resources. This study is based on agricultural meteorological data from 13 meteorological stations in the Tibet Autonomous Region from 1979 to 2020 and forecast data from six climate models in CMIP6. It examines the spatiotemporal changes in the main meteorological elements during the growing period of highland barley in the Tibet Autonomous Region during the historical observation period （1979-2020） and the future （2021-2100） under four typical scenarios （SSP126， SSP245， SSP370， and SSP585）. It focuses on the spatiotemporal distribution characteristics of Crop Water Requirement （CWR） and Irrigation Water Requirement （IWR） for highland barley in the near term （2021-2050） and quantifies the impact of the main climate elements on the interannual variation of CWR. The results show： ① During 1979-2020， the interannual variations of the main meteorological elements during the growing period of highland barley in the Tibet Autonomous Region were characterized by a significant increase in average temperature， a non-significant increase in annual precipitation， and a significant decrease in average wind speed （WND）， relative humidity （RH）， and net radiation （Rn） at the surface. During the historical observation period， the multi-year averages of CWR and IWR were 439.4 mm and 342.7 mm， respectively， both showing a non-significant decreasing trend annually； ② CWR showed a significant positive correlation with temperature， WND， and Rn， and a significant negative correlation with RH. Among them， the decrease in Rn had the greatest impact on the interannual variation of CWR during the observation period； ③ By the end of this century， the temperature and precipitation during the growing period of highland barley are expected to continue to rise， RH will increase by 2.1% to 8.3%， WND will change by -0.4 m/s to 0.8 m/s， and Rn will decrease by 3.4% to 6.2%. In the near term， CWR is expected to change by -29.3 to 13.6 mm， and IWR will decrease by 23.7 to 113.0 mm. The results of this study can provide a scientific basis and reference for adaptive management of agricultural water resources in the Tibet Autonomous Region under the background of global climate change.

Water distribution is an important mode of the pipe network operation. In order to explore the basic water hydraulic characteristics near the right-angled branch of the circular channel， DN315 PVC round pipes were used to carry out tests under 5 flow rates （30， 35， 40， 45， and 50 L/s） and 5 split ratios （0.1， 0.2， 0.3， 0.4， and 0.5） in this paper. Measurements of the water depth and three-dimensional instantaneous velocity on typical sections were recorded， using the Acoustic Doppler Velocimeter （ADV）， and the mean velocity distribution and the head loss near the unpressurized pipe branch were performed. The research shows that： the surface line of the main pipe near the right-angled branch generally decreased first and then increased. High plugged water level of the large flow （45 L/s） requires attention to the headroom. The split ratio mainly affected the water level in the mouth part. The longitudinal flow velocity through the branch decreased， while the transverse flow velocity through the branch increased. The vertical and transverse flow velocity of the upper and lower the branch were distributed symmetrically， and the velocity near the right-angled branch side was larger in the area of the bleeder. The longitudinal velocity was distributed in a parabolic vertical direction， and the longitudinal velocity appeared negative at the middle axial section of the bleeder， that is， there was a reflux phenomenon. There was no negative velocity of the transverse velocity， that is， there was no lateral circulation， and the transverse velocity was distributed in a concave vertical direction. The diverter widths of horizontal flow field increased with the increase of the split ratios， and the diverter widths of middle section were larger than that of other layers. Head losses were different under different flow rates and spilt ratios， and the coefficient of total head loss was the smallest when the diversion ratio was 0.4 and the flow rate was 50 L/s. This study is of great significance to guide the design and operation of pipe networks.

The persistent and escalating demand for petroleum has underscored its status as a significant organic pollutant in both groundwater and soil environments. Particularly， the light petroleum products， such as diesel and gasoline， exhibit heightened migration capacities owing to their lower viscosity so， the leakage of light petroleum presents a substantial pollution potential to both groundwater and soil environments. To undertake a comprehensive and accurate analysis of the distribution and migration patterns of diesel oil after site contamination， this paper employs a one-dimensional soil column as the physical model. The research focuses on the utilization of 0# diesel oil as the primary object of study and relies on the fundamental principle of Darcy's law. The investigation entails a one-dimensional soil column test conducted within an indoor porous medium characterized by three distinct particle sizes： fine sand， silt sand， and quartz sand. The study aims to scrutinize the rate of movement of diesel oil under the influence of varying medium particle sizes， different fluids， and diverse water contents in the non-saturated state. Moreover， it delves into the exploration of the change characteristics observed in different saturated media， with a specific emphasis on alterations in saturation and two-phase flow concerning the seepage time coefficient. Key findings from this study reveal that the infiltration rate of diesel fuel exhibits a direct proportionality to the particle size of the medium. Specifically， the infiltration rate hierarchy from large to small is identified as quartz sand > fine sand > silt sand. Within the same medium， the rate of movement of the oil phase is observed to be smaller than that of the water phase. Quartz sand， fine sand， and silt sand， the three media under consideration， display v _oil values smaller than v _water by 44.6%， 65.3%， and 64.3%， respectively. Across the research media， the rate of diesel fuel movement displays a nuanced trend of increasing and then decreasing with the rise in the water phase saturation of the medium. A comparative analysis of the movement rate under optimal moisture content further elucidates that the influence of particle size on the movement rate is smaller than the influence of water content. Notably， the movement rate reaches its maximum when the medium is at optimal water content. At this time the impact of particle size on the rate of movement is very small. In addition， diesel and water interactions are found to exert a significant impact on the infiltration coefficient. As media saturation diminishes， the interactions between diesel and water gradually weaken， leading to a convergence of diesel infiltration coefficients towards their counterparts in the water-saturated state. In addition to the research findings， this paper engages in an insightful discussion on various aspects， including oil-water movement rates， permeability rates， residual water phase permeability enhancement mechanisms， and the transportation characteristics of diesel fuel in the context of packaged gas belts. Overall， this comprehensive study not only provides a scientific foundation for the development of more effective pollution prevention strategies but also contributes invaluable insights into optimizing pollution treatment technologies， improving treatment efficiency， and mitigating environmental risks. Simultaneously， the study offers theoretical guidance and a robust basis for the treatment and remediation of diesel site pollution.

To investigate the effects of soil temperature and moisture on soil respiration rate of different land use types in the extreme arid ecological migration area， and to provide scientific support for accurately revealing the carbon cycle characteristics of different land use types in the study area. Soil respiration rate， soil temperature， and soil moisture content were measured in mid-May， June， and July 2023 using the LI-8100 soil carbon flux measurement system and soil moisture monitor， dividing the study area into four land use types： Wild grassland， Caragana forest， original landform， and Cultivated land. The results showed that. ① the overall soil respiration rate was as follows： Cultivated land > Wild grassland > Caragana forest > Original landscape. Soil respiration rates of different land use types were significantly positively correlated with temperature before reaching the optimum temperature （P<0.05）， and exceeding the optimum temperature would reduce soil respiration rates. ② The soil respiration rates of different land use types were well fitted to the exponential model with the soil temperature at 5 cm depth， with Q ₁₀ values ranging from 3.18 to 4.66， and the correlation between soil respiration rates and the soil temperature at 10 cm depth was significant （P<0.05） in the original landform and Cultivated land. ③ The linear correlation between soil respiration rate and soil moisture content （10 cm） was not significant （P>0.05）， and the interaction between soil temperature （5 cm） and soil moisture content （10 cm） was significantly correlated （P<0.05） for the three land-use types except Cultivated land. Different land use types have significant effects on CO₂ emissions in extreme arid ecological Immigration area， and soil temperature and moisture together are the main factors in the variation of soil respiration rates. The development of rational land-use policies that take into account the regional climate can further help to achieve the “dual-carbon goal”， with a view to providing a theoretical basis for land-use master planning in ecological migrant zones with extreme aridity.

To thoroughly investigate and comprehend the multifaceted response of river morphology and hydrodynamic characteristics to extreme floods in a branching river section， a comprehensive study was conducted on the Qingyuan Lunzhou section， which represents the lower reaches of the Beijiang River. This study employed a combination of field research， riverbed evolution analysis， and numerical simulation methods to systematically examine and elucidate various aspects， including the water flow characteristics， intricate changes in riverbed deformation patterns， sediment particle size distribution dynamics， and overall water level fluctuations during the once-in-a-century flood in the June 2022 flood event. The results indicated that during the “22·6” flood， the main stream of water shifted to the left due to the inertial effect， causing significant damage to the infrastructure in the Lunzhou Island. Moreover， after the water discharged from the canyon， a decrease in flow velocity and sediment carrying capacity led to severe sedimentation in the island head area and the right branch of the river， while the left branch experienced scouring. Additionally， differences in flow velocity between the island head area and the left and right branches resulted in variations in sediment particle size distribution. The sediment particle size in the island head area was notably larger compared to that in the left and right branches of the riverbed. Following the “22·6” flood， the elevation of the riverbed led to a significant increase in water level compared to before the flood. Moreover， the diversion ratio of the left branch increased. Specifically， under an inflow of 5 000 m³/s， the upstream water level of the island head rose by almost 1m， and the diversion ratio of the left branch augmented by approximately 16% compared to pre-flood conditions.

River ice flood occurs frequently in regions with high latitudes and high altitudes， often resulting in ice jams or dam floods that pose serious threats to personal and property safety. Therefore， comprehensive consideration of all factors to conduct scientific risk evaluation is the primary prerequisite and essential requirement for preventing the risk of freezing flood disasters. This study establishes an ice flood disaster risk evaluation model based on catastrophe theory， introduces the Gray Relational Analysis method to rank basic indicators and evaluates the ice flood disaster risk in the upper reaches of Heilongjiang River. Considering the correlation between different indicators， the Pearson correlation coefficient method was employed to streamline the indicator set and select representative years. The obtained results were compared based on the risk ranking of these representative years and Hierarchical Cluster Analysis-Catastrophe Theory. The findings reveal that under the influence of hydrological， meteorological， social and economic factors， the risk level of ice flood disaster in the three districts of Mohe， Tahe and Huma in the upper reaches of Heilongjiang River during the period from 2000 to 2020 has shown an overall trend of increasing and then decreasing. Among them， factors such as snow depth， water level， ice thickness， and temperature show a remarkably high correlation with the frequency of ice flood disasters. Social factors such as population， agriculture， economy， and healthcare also influence the risk level after ice flood events. The Mohe River section， due to its complex and steep river terrain， harsh climatic conditions， and relatively high population density， exhibits an overall elevated risk level. The risk membership values of the Gray Relational Analysis-Catastrophe Theory model were distributed in the range of 0.85 to 0.93， and it has better risk ranking and safety margin than the Hierarchical Cluster Analysis-Catastrophe Theory model， which verifies the validity and practicability of the model in the evaluation of the risk of ice flood disaster， and provides a new scientific method and theoretical basis for further research into ice flood disaster risk evaluation.

Promoting the synergistic development of agricultural water use efficiency， agricultural economic development and agricultural ecological environment is an inevitable choice to realize the high-quality development of agriculture in the Yellow River Basin. Based on the provincial panel data of 9 provinces （and regions） along the Yellow River Basin from 2005 to 2020， a comprehensive development evaluation index system of agricultural water use efficiency—agricultural economic development—agricultural ecological environment （WEE） was established in this paper. Additionally， the coupling coordination model was adopted to measure the coupling coordination development level of the WEE composite system， and the obstacle degree model was further applied to identify the obstacle factors. The results showed that： ① The agricultural water use efficiency， agricultural economic development and agricultural ecological environment subsystems showed upward trends with different degrees of fluctuation from 2005 to 2020. ② The WEE composite system in the Yellow River Basin was in a highly coupled state， with the degree of coordination progressing from barely coordination to primary coordination and showing a spatial pattern of “high in the west and low in the east”. Moreover， the provinces （and regions） with lagging agricultural ecological environment were the most and the provinces （and regions） with lagging agricultural water use efficiency were the least. ③ The main obstacle factors corresponding to each subsystem were the strongest in blocking the agricultural water use efficiency subsystem while the weakest in blocking the agricultural economic development subsystem. Boosting the transformation and upgrading of traditional agriculture to modernized agriculture， breaking down provincial and regional barriers to promote the free flow of agricultural resource elements， and formulating relevant policies in accordance with local conditions are crucial measures to strengthen the synergistic development of agricultural water use efficiency， agricultural economic development and agricultural ecological environment in the Yellow River Basin and the provinces （and regions）.

Ecological flow is the basis for the health and stability of river ecosystems. Against the background of global climate change and increased human activities， the impact on ecological flow is becoming increasingly significant. In order to explore the response of ecological flow to future environment changes in the Dawen River Basin， the Jinan section of the Dawen River Basin was taken as the research object. The SWAT model was used to analyze the spatiotemporal changes of runoff under future land use and climate scenarios， and to evaluate the ecological flow guarantee rate and response rules of Chenbei and Maxiaozhuang which are the Dawen River water resources dispatch control section.The results show that in the future changing environment， the land use will show the characteristics of reduced cultivated land area and increased urban area； climate change will be characterized by increased precipitation and rising temperatures， in the Jinan section of the Dawen River Basin. Future land use changes will cause runoff to decrease by 2%， climate impact will reduce runoff by 1%~4%， while the two work together to reduce runoff by 3% to 5%. Future climate change will weaken the correlation between precipitation and runoff. Spatially， future land use will enhance the positive spatial correlation of runoff， while future climate change will weaken the positive spatial correlation and significance level of runoff， affecting the spatial distribution characteristics of runoff. Future land use changes will have little impact on flows and the ecological flow guarantee rate of Chenbei and Maxiaozhuang. However， future climate change will change the shape of flow hydrographs of Chenbei and Maxiaozhuang， and the ecological flow guarantee rate of Chenbei and Maxiaozhuang increased from 73%， 74% to 97%， 98%， and the proportion of basic ecological flow guarantee rate of more than 90% increased from 14% to 93%. Among future land use and climate factors， precipitation is the main controlling factor for the ecological flow guarantee rate of Chenbei and Maxiaozhuang. The research results can provide technical support for the ecological dispatch and management， to cope with the changing environment in the Dawen River Basin.

Under the impacts of extreme climate conditions and urbanization， the issue of urban pluvial flooding is becoming increasingly severe. To effectively address the urban flooding problems in the low hydraulic gradient area of Zhuhai Airport and enhance the operational safety of the airport， this study utilizes the InfoWorks ICM model to analyze the changes in the underlying surface， the drainage capacity of the pipeline， the surface inundation situations， and the flood risk levels under different rainfall patterns. This is done to evaluate the effectiveness of the current renovation projects in flood control and to explore the airport's adaptability to different rainfall patterns， thereby providing a scientific basis for future flood prevention strategies. The research results indicate that the simulated water depths are approximately 10% different from the observed flood depths， confirming the reliability of the model in analyzing the characteristics of urban flooding in the area. After the renovation of the airport project， the flood risk within the study area has significantly decreased， with a substantial reduction in the areas of different risk levels， and an enhanced response capability to various rainfall types. Particularly， in the case of a 100-year rainfall event， the renovation has significantly improved the performance of the pipeline， increasing the proportion of under-capacity pipe sections length to 58.08% and reducing the proportion of over-capacity sections length from 49% to 16.33%. As a result， the area of urban flooding in the study region was reduced by 88%， and the area with water depth exceeding 50 cm was reduced by 85%. Moreover， when the peak rainfall coincides with the peak tide， the flood risk increases with the delay of the peak rainfall， especially for events with return periods between 5 to 50 years. The renovation has improved the adaptability to central-type and delayed-type rainfall design events， reducing the proportion of pressurized pipe length， demonstrating the effectiveness of the renovation works in enhancing the airport's resilience to extreme rainfall events. Nonetheless， some local low-lying areas within the study area still face the risk of waterlogging， necessitating continuous monitoring and advancement in the management of flood-prone spots.

In order to study the clogging mechanism of the drip irrigation system of Yellow River diversion in the field， and to reduce the clogging of the irrigation system in the field， based on the characteristics of sediment in Zuncun irrigation district of Yuncheng， Shanxi Province，SolidWorks is used to model and design the flow path of emitters. The simulation parameters were set according to the actual engineering conditions of drip irrigation， and Ansys Fluent simulation software is used to simulate the flow passage of different types of emitters. The turbulent characteristics such as pressure， velocity and turbulent kinetic energy of the emitters， as well as the particle trajectories are studied to reveal the internal flow mechanism of the emitters. The pressure of the fluid basin inside the emitters decreases linearly with the flow channel units， and the pressure drop gradient is linearly related to the number of flow channel units. The fluid in the mainstream area is updated quickly， and is not prone to sedimentation. The vortex area of the flow channel and the chamfered parts of the storage tank are the main parts where sedimentation occurs.The turbulent kinetic energy is lower in the vortex region of the channel and the chamfering part of the water storage tank than in the other regions of the channel， so the turbulent flow can not be formed or maintained， which is not conducive to sediment transport， thus forming a plug. The simulation results show that， the analysis of flow velocity， turbulent kinetic energy and streamline in the inner structure of the emitters shows that the low velocity zone and the chamfer and side wall of the storage tank are the main locations of sediment deposition in the emitters.

Unsafe human behavior is an important cause of safety accidents. In order to study the factors that affect the unsafe behavior of water conservancy construction personnel， this article analyzes 280 water conservancy construction accident cases using text mining technology， and uses R language to form a visual word cloud graph to obtain 32 factors that affect unsafe behavior. Using Ucinet software to construct co-occurrence networks and calculate centrality， identify key factors affecting unsafe behavior of water conservancy construction personnel.

To explore the suitable mode of reclaimed water irrigation for sunflower in Hetao Irrigation District， this paper set up five groups of Yellow River water （H）， which included T1 （HHH）， T2 （HZZ）， T3 （ZHZ）， T4 （ZZH） and T5 （ZZZ）， and reclaimed water （Z） irrigation modes for the key growth stages of sunflower （emergence-squaring stage， squaring-filling stage and filling-waxy stage）， and the mulched drip irrigation technology was applied to carry out the two consecutive years field experiment. The results showed that， the Yellow River water amount applied for treatments followed T5<T2<T4<T3<T1， while the reclaimed water amount applied for treatments followed T1<T3<T4<T2<T5. The reclaimed water and Yellow River water irrigation had no significant effect on the 0~40 cm soil pH inside and outside the film. The higher of the reclaimed water irrigation quota， the greater of the soil salinity variation inside the film， and the content of typical heavy metal elements in soil and grains. The corresponding alternate irrigation mode of T2 treatment was more conducive to promoting the growth of sunflower， increasing grain yield， and increasing the content of crude protein and crude fat in grains than other irrigation methods； However， the contents of arsenic， lead， cadmium and chromium in soil and grain of T3 treatment were lower than other treatments. Compared with T1 treatment， the Yellow River water applied amount was saved by 100~120 mm， and the grain yield， biomass， crude protein and crude fat content of grain were increased by 4.34%~7.19%， 6.20%~6.68%， 9.25%~20.50% and 7.39%~13.37%， respectively. Short-term reclaimed water irrigation will not lead to the excessive content of heavy metal elements in sunflower grains and 0~100 cm soil after sunflower harvest. In order to save water and control salt， increase production and improve quality， this paper suggests that the corresponding alternate irrigation mode of T3 treatment is the suitable reclaimed water irrigation mode during sunflower growth period in Hetao Irrigation District. The results of this study can provide theoretical guidance for the safe and efficient application of reclaimed water for sunflower cultivation in Hetao Irrigation District of Inner Mongolia.

The seepage failure of piping is one of the main reasons contributing to the break of earth-rock dam. It is of great significance to study the change of seepage field in the piping process of earth-rock dam by model experiment. By using the method of simulating piping leakage with preset piping passage， a piping break-out model of scale indoor homogeneous earth dam is established， and the seepage field data of the earth dam model are obtained by arranging a small-range percolator， the variation of seepage field in the whole process of earth dam model from impoundment to seepage failure to break is deeply analyzed and studied. It is found that，during the storage stage， the seepage pressure at the same axial distance is lower than that at the non-piping section， but the peak time is earlier than that at the non-piping section. During the burst stage （open flow and breach formation stage） ， the seepage pressure in the dam body drops suddenly， and the closer to the piping section， the earlier the time and the larger the magnitude of the pressure drop. This knowledge can be used for reference in the prediction and early warning of piping failure of earth-rock dams.

The Jiuxi Drainage Pumping Station in Hangzhou City， Zhejiang Province is equipped with six large mixed flow pumps with guide vane， with a single unit flow rate of 50m³/s and a single motor power of 10 000 kW. It is the largest mixed flow pump with vane diffuser in China. Affected by the upstream inflow and downstream Qiantang River tide， the pump head has wide range of variation. The minimum head is 1.71 m， the design head is 14.0 m， and the maximum head is 15.4 m. In order to ensure that the pump unit maintains safe and stable operation within a large range of head changes， combined with the building layout and operation conditions of the Jiuxi pumping station，the downstream tidal gates were fully utilized to increase the minimum head， and the effects of full regulation and variable frequency regulation on optimizing low head operating conditions were analyzed and compared in detail， and comprehensive measures to improve the stiffness and strength of the pump unit were adopted. A detailed analysis of the pump unit operating conditions and selection scheme is conducted， and suggestions for frequency conversion adjustment and operation optimization of the pump unit are proposed， providing reference for similar pumping stations.

Inundation treatment of large and medium-sized reservoirs flood treatment is an important foundation of project construction， involving the interests of the state， collectives and individuals. It is characterized by strong policies， complex field conditions and intertwined interests. Among them， there is a big controversy over the determination of beach land ownership， land classification identification， and the calculation of compensation fees. Based on the practice of inundation treatment during the construction of large and medium-sized reservoirs in Yuanli， Hunan Province， this paper proposes the relevant laws and policies for determining land ownership and land type， as well as the path and method of calculating land compensation fees， related taxes and fees， which can serve as a reference for land acquisition compensation and resettlement workers in water conservancy and hydropower projects.

Aiming at the problem of pressure pulsation in volute channel and radial force on impeller caused by unsteady flow of centrifugal pump， a method of changing the base circle diameter of volute was proposed to change the gap between impeller and tongue， so as to change the pressure pulsation in volute and radial force on impeller. Based on SST k-ω turbulence model and SIMPLE algorithm， the influence of radial clearance on volute pressure pulsation and radial force on impeller was studied. Four kinds of volute with different base circle diameters were designed respectively. The base circle diameters of the volute were 180， 184， 200 and 220 mm， and the corresponding clearance rates were 3.45%， 5.75%， 14.94% and 26.44%， respectively. The pressure pulsation characteristics of the inner wall of the volute and the radial force acting on the impeller under different clearance rates were obtained by unsteady calculation of the four models. The results show that when the impeller deviates from the design condition， the radial force on the impeller reaches 5~7 times of the design condition， and the pulsation amplitude of the radial force reaches more than 10 times of the design condition. With the increase of the clearance rate， the amplitude of the radial force pulsation of the impeller decreases. When the clearance rate increases from 5.75% to 26.44%， the pulsation amplitude of the pressure pulsation at the tongue decreases by more than 50%. With the increase of the clearance rate， the pressure pulsation amplitude of the inner wall of the volute decreases. When the clearance rate is 26.44%， the pressure pulsation amplitude of the inner wall of the volute is about 50% of that when the clearance rate is 5.75%. Under the condition of low flow rate， the generation of vortices in impeller channel can be reduced by increasing the clearance rate appropriately.

Vegetables are important cash crops， and it is of great significance to people's life to guarantee long-term high yields of vegetables in total. In order to investigate the remote sensing monitoring model of the growth condition of Chinese cabbage during the whole reproductive period， this study takes Chinese cabbage under different water and nitrogen treatments as the research object， uses UAV multispectral remote sensing technology， optimizes the spectral data （band reflectance， vegetation index） by cluster-factor analysis as input variables， and it takes the soil water content and relative chlorophyll content （SPAD） observed quasi-simultaneously on the ground as output variables. The SPAD and soil moisture content monitoring model of Chinese cabbage leaves were constructed by using three methods： Extreme Learning Machine （ELM）， Multiple linear regression （MLR）， and Particle Swarm Optimization-Extreme Learning Machine （PSO-ELM）.The spatial and temporal distribution characteristics of soil moisture and SPAD in the experimental area were analyzed by use of inverse images. The main findings were as follows： ① Different water and nitrogen treatments had highly significant effects on SPAD of Chinese cabbage， while water treatments were not significant. ② Cluster-factor analysis obviously eliminated the multicollinearity problem between input variables， and the VIF among the treated variables were all 1. ③ The validation set determination coefficients R ² of the soil water content prediction models constructed by ELM， MLR， and PSO-ELM models were 0.54， 0.53， 0.66， respectively， and the root mean square errors RMSE were 0.01， 0.03， 0.03 respectively， and the performance deviation rates RPD were 1.42， 1.46， 1.72， respectively； the constructed leaf SPAD prediction models R ² were 0.65， 0.75， 0.74， RMSE were 2.39， 2.43， 2.46， and the RPD were 1.66， 2， 1.96， respectively. By comprehensive comparison， PSO-ELM has the highest simulation accuracy for the two indexes. The results of the study provide effective reference value for the research of prescription decision during the growth process of Chinese cabbage.

Due to fine sand′s unique physical properties and susceptibility to erosion， the protection of fine sand bank slopes is of paramount importance. Taking a portion of the Xiang River's fine sandy bank as the research object， considering this area′s high rainfall frequency， fast flow velocity， and susceptibility to scouring of the riverbanks， the anchor rod-concrete prefabricated grid revetment structure is proposed in this study. The three-dimensional mathematical model of slope protection is established by using FLAC3D， a finite difference software， and incorporating the selected terrain and soil property parameters of the fine sandy slope section. The impact of this revetment structure on the stability of the slope is discussed. The results show that under the action of anchor rod tension and the self-weight of the prefabricated grid， the stress field exhibits a zonal distribution. The anchor rod-concrete prefabricated grid revetment structure greatly constrains the horizontal displacement of the soil mass， weakens the development of the slope's plastic zone and the increment of maximum shear strain bands. The safety factor of slope stability is significantly improved. The length of the anchor rod and the angle of insertion into the soil have a significant impact on enhancing the overall stability of the fine sandy slope. An anchoring scheme with an 8-meter long anchor rod and an insertion angle of 30° can be considered for practical engineering reference.

In order to explore the water permeability effect， soil preservation and anti-silting performance of subsurface drainage pipes under different conditions of outsourced filter material， five types of subsurface drainage pipe outsourced filter material schemes were set up， namely sand filter material （A）， 68 g/m² geotextile （B）， 90 g/m² geotextile （C）， 68 g/m² geotextile + sand filter material （D）， and no outsourced filter material （E） scheme as a control.Through the indoor penetration test， the monitoring and investigation of spring irrigation and autumn watering in the field， the influence of different filter materials on the water permeability， soil preservation and anti-silting performance of the subsurface drainage pipe were comprehensively analyzed.The results show that the attenuation rate of the drainage flow of scheme A， B and D was stable at 5.60% on average， and the attenuation rate of scheme C was 11.15%， second only to scheme E （15.094%）.The permeability coefficient of different filter media in the stable state ranged from 7.46×10^-4 cm/s to 9.46×10^-4 cm/s， and GR≤3；Compared with spring irrigation， the soil loss of each scheme in autumn was reduced by 42% on average， and the soil loss attenuation rate of scheme D was only 35%， which was lower than other schemes （P < 0.05）.At the same time， the soil loss d ₉₀ of scheme A to D was 14.8， 18.50， 9.0 and 15.50 μm， respectively， and the soil preservation performance was significant compared with scheme E （d ₉₀=23.33 μm）；The amount of silted soil in scheme B， C and D was 12.54， 17.64 and 7.00 g， respectively， and the amount of silt in scheme D was significantly lower than that in other schemes where only geotextile is laid， indicating that scheme D has the best anti-silting effect.In summary， according to the soil properties of the downstream of Hetao irrigation area， it is recommended to preferentially select scheme D （68 g/m² geotextile + sand filter material） as the filter material for subsurface drainage pipes in the irrigation area.The research results can provide a reference for selecting suitable filter material for subsurface drainage pipes in the downstream of Hetao irrigation area.

The Three Gorges Hydropower Station has 34 units with a total installed capacity of 22 500 MW. It is a key power source for the backbone power grid of State Grid Corporation of China′s “West-to-East Power Transmission” project and “North-South Interconnection” project， supporting the safe and stable operation of the grid. However， the annual maintenance work at the Three Gorges Hydropower Station is complex and highly uncertain due to the large number of equipment， diverse unit models， and varied demands for equipment technological upgrades. Additionally， the workload for manual operations is significant. To address these challenges， a maintenance planning platform has been developed based on the SpringBoot microservices architecture. The platform includes the Three Gorges Hydropower Station Operation Scheduling and Optimal Maintenance Arrangement System. It provides a hierarchical operational service framework for decision-makers， managers， implementers， and operators at the power plant. This platform enables comprehensive digital management and control of the yearly maintenance planning， execution， feedback， and adjustments for the equipment at the Three Gorges Hydropower Plant. Furthermore， considering different maintenance requirements and prioritizing safety and stability during the maintenance process， multiple maintenance plan options have been proposed and optimized. Currently， this platform effectively serves the routine maintenance scheduling work at the Three Gorges Hydropower Station.

In response to the problems of untimely runoff forecasting， inaccurate output forecasting， large load control deviation， untimely response， and poor output stability in the application of existing power load control methods for cascade hydropower stations， this article conducts a demonstration and analysis of the power load frequency division control method for cascade hydropower stations from the perspective of considering output constraints and electricity demand. Taking the Monkey Rock cascade hydropower station on the main stream of the Dadu River in Kangding City， Ganzi Prefecture， Sichuan Province as an example， based on the hydraulic regulation performance， the location of the cascade group， and tasks undertaken by the cascade hydropower station， the total energy storage value of the cascade hydropower station is calculated and output constraints are set based on this. Wavelet transform technology is used to predict the total load of the cascade hydropower station， and then the power load is divided into three regions： low frequency， medium frequency and high frequency region. Finally， based on the ordered power consumption plan and actual power demand of different regions， appropriate frequency division control methods and execution measures are formulated for the three regions to effectively regulate and control the power load of cascade hydropower stations. The experimental results show that the power load frequency division control method considering output constraints and electricity demand has achieved effective regulation and frequency division control of the power load of cascade hydropower stations. The proposed method has the advantages of high efficiency， small deviation， low risk， and energy conservation and consumption reduction. It has improved the efficiency of runoff forecasting for hydropower stations， reduced the fluctuation value of hydropower station output， reduced the energy loss of hydropower units， and shortened the response time of power load control It provides a solid guarantee for the stable and efficient operation of cascade hydropower stations， and has high application and promotion value.

The stability of slopes under complex geological conditions is obviously affected by factors such as structural plane and rock mass properties， and its accurate evaluation is very important for the safety of slope construction. Based on the construction project of the inlet slope of the diversion tunnel of the Cihaxia of the Yellow River， this paper proposes a comprehensive evaluation method of slope stability based on the stereographic projection theory， the two-dimensional limit equilibrium and the three-dimensional limit equilibrium method. Firstly， based on the stereographic projection theory， the unstable block of slope 4# toppling body with complex structural plane is qualitatively described. Then， the two-dimensional limit equilibrium and three-dimensional limit equilibrium methods are used to analyze the risk of slope instability induced by layer-by-layer excavation during construction. Finally， from the perspective of multi-method comprehensive evaluation and cyclic optimization， a targeted support optimization scheme is proposed according to the design principle of ' less excavation + strong support '， and the optimization scheme is evaluated from the perspective of safety and economy. The calculation results show that the slope stability safety factor of the large excavation scheme is about 1.17~1.19， and the safety factor of the small excavation scheme is about 1.078. The slope safety of the large excavation scheme is higher than that of the small excavation scheme. After the support optimization of the small excavation scheme， the safety factor of the slope stability increased to 1.159~1.183， the slope stability changed from critical stability to stability， and the support optimization effect is remarkable. Based on the safety and economic evaluation of slope excavation， it can be seen that the proposed ' less excavation + strong support ' optimization scheme meets the safety control standards of slope excavation related specifications， and has good economic benefits and engineering value， which can provide reference for related projects.

Pump storage is of great significance to the development of renewable energy and the construction of a new energy system， and help to achieve the “dual carbon” goal. Fully understand the functions and functions of pumping storage， sort out the policy evolution and development process in the process of modernization of China's pumping storage， analyze the current status of Chinese pumping storage， and look forward to its future. The inherent relationship between the modernization of the entire country is conducive to promoting the high-quality development of the new stages of pumping in the new stage， and it is expected to accelerate and promote the formation of a modern industry with strong international competitiveness in my country.

In order to solve the complex problem of joint optimization of water， fire， wind and solar multi-energy complementary power generation systems， this paper proposes a two-layer optimization modeling and solution method for the joint scheduling problem of water， fire， wind and solar multi-energy complementary systems， in which the upper layer uses the minimum mean square deviation of residual load and the minimum expected mean value as the objective function to jointly optimize the water， wind， solar and clean energy bundling， and the lower layer takes the minimum economic index as the objective function to optimize the adaptive residual load of thermal power. Taking the typical spring， autumn， summer and winter power grid load and the output process of wind power and photovoltaic power in Jiangxi Province as the research object， a case analysis was conducted. The model is solved by using the DPSA-POA and intelligent algorithm hybrid optimization method proposed by the research team， which verifies the effectiveness of the two-layer optimization modeling and solution method proposed in this paper. It is also found that compared with the complete consumption of wind and solar power， the overall operating cost of the discardable wind and solar power scenario has increased， but the overall operating cost has reduced. The case analysis results of the power grid load and the output process of wind power and photovoltaic power in Jiangxi Province in spring and autumn show that the total output of thermal power has increased by 5.79%， and the overall operating cost of the multi-energy complementary system has decreased by 4.97%. The case analysis results of the grid load and the output process of wind power and photovoltaic power in Jiangxi Province in summer show that the total output of thermal power has increased by 0.32%， and the overall operating cost of the multi-energy complementary system has decreased by 1.95%. The case analysis results of the grid load and the output process of wind power and photovoltaic power in Jiangxi Province in winter show that the total output of thermal power has increased by 10.70%， and the overall operating cost of the multi-energy complementary system has decreased by 6.78%. This method provides a new idea for solving the complex problem of water， fire， wind and solar multi-energy complementary joint optimization.

The initial in-situ stress of rock mass is an important part of underground engineering research. Relying on the large-scale underground plant project， the three-dimensional hydraulic fracturing method and the conventional hydraulic fracturing method were used to measure the in-situ stress of hole ZK1 in the tunnel and surface hole ZK2 respectively to obtain the initial in-situ stress of rock mass. Based on the measured data， the three-dimensional numerical simulation method was used to calculate the in-situ stress field inversion， and obtained the distribution law of the in-situ stress field in the required engineering area. The results show that the initial in-situ stress can be effectively obtained by the hydraulic fracturing method， and the underground stress obtained by the three-dimensional hydraulic fracturing method is more accurate and can be confirmed by the vertical hole test data. The calculated value of in-situ stress obtained by numerical simulation is consistent with the measured value. The layout of plant tunnels is reasonable， and the probability of rock burst in the engineering area is low. The field in-situ test results and the regression in-situ stress field distribution rules can provide effective scientific support for engineering design.

The dynamic characteristics of the transition process and the cost of surge chamber construction are the two main aspects to be considered in the design of the surge chamber body. Selecting the parameters of the surge chamber structure to optimize both of these aspects is of great significance for the construction and operation of hydropower stations. To address this challenge， a surge chamber body shape optimization strategy based on the Non-dominated Sorting Genetic Algorithm III （NSGA-III） and Technique for Order of Preference by Similarity to Ideal Solution （TOPSIS） is proposed.This strategy considers the optimality of both the dynamic characteristics of the transition process and the engineering investment. Firstly， a refined model of the hydroelectric system is established based on the feature line method. Secondly， by taking the surge chamber diameter， impedance hole diameter， and installation position as decision variables， the paper establishes a large fluctuation optimization model targeting large fluctuation dynamic characteristics （Maximum head of unit+Maximum rate of increase of unit speed） and surge chamber volume， as well as a small load disturbance optimization model targeting rotational speed overshoot and ITAE. NSGA-III is introduced to obtain the Pareto solution sets under the two optimization models. Finally， using the TOPSIS evaluation method， the Pareto solution sets are further evaluated with the above four optimization objectives as the index system. This process leads to the identification of the surge chamber body type that considers the optimality of both the dynamic characteristics of the transition process and economic factors. The results indicate that， compared with the lowest-scoring scheme， the optimal scheme can effectively improve the integrated regulation characteristics of large and small fluctuations under the premise of sacrificing a small surge chamber economy， and realizes the goal of balancing the construction cost of surge chamber and the integrated regulation characteristics of large and small fluctuations. These findings are of great significance in guiding the structural design of surge chambers in hydropower stations.

With the large-scale integration of photovoltaic power generation into the power grid， the resulting uncertainty of the available power supply at the source end has become increasingly prominent. Accurate prediction of photovoltaic output plays a crucial supporting role in optimizing the allocation of power grid resources and improving photovoltaic consumption capacity. This article studies the key factors that affect photovoltaic output and constructs a photovoltaic output prediction model using historical meteorological characteristic data as input. In practice， the model is optimized from the algorithm level to address the subjective and objective issues that exist. ① In response to the problem of small sample size and frequent changes in meteorological characteristics in the historical operation of photovoltaic power plants， leading to many sparse feature samples， the ADASYN adaptive adoption algorithm was introduced to rebalance the dataset； ② A photovoltaic output model based on meteorological features was constructed using the XGBoost algorithm and compared with traditional BP neural networks. By comparing the actual historical data prediction results of a photovoltaic power plant， combined with ADASYN oversampling and XGBoost algorithm， the accuracy of the model can be effectively improved. Compared to the BP neural networks， MAE， RMSE， MAPE and R ² of the ADASYN- XGBoost algorithm has improved by 66.7%， 68.9%， 58.0% and 1.6%， respectively， indicating that the evaluation indicators are significantly optimized.

Under the vision of the "dual carbon" goal， it is urgent to accelerate the development of clean energy and build a green and low-carbon new power system. However， clean energy represented by solar energy is affected by natural factors and has strong volatility and randomness， making it difficult to consume in large quantities through grid connection. Therefore， considering the long construction period and significant impact of natural inflow on the regulation performance of traditional hydropower， adding reversible units to traditional hydropower units to form a hybrid pumped storage power station increases its hydropower regulation capacity， and can operate in conjunction with photovoltaic power stations to suppress the volatility of photovoltaic power generation and promote grid connected consumption. To explore the operation mode of the water solar storage complementary power generation system with hybrid pumped storage power stations under a large number of photovoltaic grid connections， this paper constructs a daily optimization scheduling model with the optimal source load matching as the objective function. The solution strategy is nested in multiple time scales from medium term to short one， using medium and long-term time scale calculation results as short-term time scale calculation boundary conditions， and the stepwise optimization algorithm and particle swarm optimization algorithm are used to solve the system operation mode under different incoming water and photovoltaic output scenarios. The results indicate that under the premise of different incoming water and different photovoltaic output processes， hybrid pumped storage power plants can adopt different operating conditions， forming a “concave” shaped output with traditional hydropower and complementing the photovoltaic output， which can not only promote photovoltaic grid connection and consumption， but also meet the load demand of the power grid. In addition， under different typical days， the daily water level fluctuations of the upper and lower reservoirs of hybrid pumped storage power stations show a trend of “discharging first and then storing” in the upper reservoir and "storing first and then discharging" in the lower reservoir. The research results provide reference for the operation mode of hybrid pumped storage power plants with a large amount of photovoltaic stations connected to the grid.

As the core equipment of hydroelectric power plants， hydroelectric generator units inevitably generate vibration and pressure pulsation problems during long-term operation. Long term vibration can accelerate the wear and fatigue of mechanical parts， reduce the lifespan and reliability of the unit， and may also lead to unstable operation of the unit， and even cause serious accidents， posing a threat to the safety of the power plant. These vibration and pulsation problems stem from multiple factors， including the dynamics of water flow， the design and manufacturing quality of impellers， and the complex interactions between the unit and the hydraulic system. These vibration and pressure pulsation issues have a negative impact on the performance， reliability， and safety of hydroelectric generators. Therefore， it is particularly important to conduct in-depth research on the vibration and pressure pulsation problems of hydroelectric generator units during operation and find effective solutions. This article analyzes the experimental data of Unit 3 of Ansha Hydropower Station and delves into the operational stability issues caused by pressure pulsation and vibration of hydroelectric generator units. By using the Wilcoxon rank-sum test and Pearson correlation coefficient to analyze the pressure pulsation， vibration， and swing signals during the operation of water turbine units， it was found that there is a strong correlation between the overall signals of hydraulic turbine units， especially in the swing signal. Finally， methods and strategies to reduce pressure pulsation and vibration issues generated during the operation of hydroelectric generator units were explored for the design， operation， and maintenance stages. By taking these measures， we can effectively reduce the negative impact of vibration and pressure pulsation， ensure the safe and stable operation of hydroelectric generator units， and contribute to the development of sustainable energy.