This paper evaluates the spatial equilibrium status of water resources in Yunnan Province from 2006 to 2022 and 2025 scientifically， and proposes a water resource spatial equilibrium evaluation model based on social network search （SNS） algorithm， mountaineering team optimization （MTBO） algorithm， bi-directional gated loop unit （BIGRU） optimization， and bi-directional long short-term memory （BILSTM） network optimization. First， 15 indicators are selected from three aspects of water resources support， water resources pressure and water resources regulation to build the evaluation index system and grade standard of water resources spatial balance， and the samples are generated by linear interpolation and random selection methods to build BiGRU and BiLSTM fitness function. Secondly， the principles of SNS and MTBO algorithms are briefly introduced. SNS-BIGRU， MTBO-BIGRU， SNS-BILSTM， and MTBO-BILSTM models are constructed by using SNS and MTBO to optimize the number of neurons in the hidden layer of BiGRU and BilSTM and the learning rate （hyperparameter）. The robustness of four models， including SNS-BIGRU， MTBO-BIGRU， SNS-BILSTM， and MTBO-BILSTM， is verified through different sample sizes and 10 consecutive runs. Finally， SNS-BIGRU， MTBO-BIGRU， SNS-BILSTM， and MTBO-BILSTM models are used to evaluate the spatial balance of water resources in Yunnan Province from 2006 to 2022 and 2025， and the evaluation results are compared with those of SNS-Support Vector Machine （SVM）， MTBO-SVM， and fuzzy comprehensive evaluation methods. The results show that： ① the models such as SNS-BIGRU have good recognition accuracy and robustness. SNS and MTBO can effectively optimize the hyper-parameter of BIGRU and BILSTM， and improve the prediction performance of BIGRU and BiLSTM. ② SNS-BIGRU and other four models evaluate the spatial balance of water resources in Yunnan Province from 2006 to 2011 as “unbalanced”， from 2012 to 2013 as “relatively unbalanced”， from 2014 to 2018 as “critical equilibrium”， from 2019 to 2022 as “relatively balanced”， and by 2025， it can basically reach the level of “balanced”. There is a 3-year difference in the evaluation results of the four models compared to SNS-SVM， MTBO-SVM， and fuzzy comprehensive evaluation methods. The model method constructed and proposed in this paper serve as a reference for the spatial balance evaluation of water resources.

Model parameter calibration is an important way to improve the simulation effect of hydrological models. In order to solve the problems of low initial population quality， prematurity and poor local search ability of traditional genetic algorithm， this paper proposes an improved adaptive genetic algorithm （IAGA） to optimize the parameters of Xin?anjiang model. The Ergodic characteristics of chaos variables are used to randomly generate the initial population and select the best， so as to improve the individual quality of the initial population. Aiming at the evolutionary process of crossover and mutation， this paper designs the discrete coefficient of population objective function to reflect the degree of population dispersion. By using this coefficient， the adaptive adjustment crossover and mutation probability operators are constructed to prevent premature convergence of genetic algorithm. Based on the ring crossover operator， the global search ability of the algorithm is improved. The adaptive non-uniform mutation operator is used to optimize the local search ability of the algorithm in real time and avoid falling into local optimum. The IAGA algorithm， traditional genetic algorithm （GA） and adaptive genetic algorithm （AGA） are applied to the parameter calibration of the Xin′anjiang model in the Qinhuai River Basin， and the performances are compared from the aspects of convergence， time-consuming， stability and effect. The results show that the IAGA algorithm has more excellent optimization ability， better convergence results， higher stability and accuracy. The flood simulation results are better than the GA algorithm and the AGA algorithm. During the calibration period and the verification period， the deterministic coefficients are higher than 0.85， and Nash-Sutcliffe efficiency coefficient are higher than 0.8， which generally meets the second-level standard of hydrological forecasting. The results show that it is feasible to improve the traditional genetic algorithm by using the above comprehensive means， and the improved IAGA algorithm has a good application prospect， which provides an effective way for the automatic calibration of Xin′anjiang model.

In recent years， uncommonly severe droughts have attacked many places in Guangdong Province， with long duration， wide impact and serious consequences， which is contrary to people’s general understanding of the water-rich areas in the south. In order to find out the causes， influencing factors and characteristics of drought in Guangdong Province， and effectively identify the weaknesses in drought disaster prevention and control， taking the typical drought-prone counties in Guangdong Province-Chaonan District in eastern Guangdong and Xuwen County in western Guangdong Province as examples， based on the natural disaster risk theory， this paper establishes a drought disaster risk assessment zoning model， which couples the three elements of hazard， vulnerability and defense， and the evaluation index system and calculation method of comprehensive risk index are put forward. The index weight is determined by analytic hierarchy process. The natural breakpoint method is used to scientifically divide the regionalization， and the risk matrix method is introduced to aggregate the drought risk and drought defense and disaster reduction ability to represent the level of drought disaster prevention and control， and the risk influencing factors and risk levels of drought disaster are qualitatively and quantitatively evaluated. The results show that， under the main influence of less natural rainfall and large demand for economic and social water， the comprehensive risk of drought disaster in Chaonan increase from west to east， most towns and streets have moderate drought risks， while the whole area of Xuwen has medium-high and above drought risks， the comprehensive risk of drought disaster in western and central areas is high. If the water supply engineering capacity， river system density and drought-defense investment level are not high， it can be determined that most towns and streets in Chaonan are medium prevention areas， and most towns and villages in Xuwen are key prevention areas. The rationality of the results is verified by typical historical drought events， and some measures and suggestions are put forward for the weaknesses of drought defense in drought-prone counties. The research results can provide technical support for improving the drought-defense and disaster reduction system in typical drought-prone counties in Guangdong Province.

With the development of society and the increasing demand for ecological conservation， the traditional integrated reservoir operation aiming at flood control and profit fail to meet the diversified requirements. Hence， the implementation of multi-objective reservoir comprehensive optimization scheduling has become increasingly urgent. In order to achieve the optimization of the comprehensive benefits of Zaoshi Reservoir and balance the social， economic and ecological benefits， the optimization dispatching model of Zaoshi Reservoir for power generation， water supply and ecological requirements is established， which adopts the improved Multi-objective Shuffled Frog Leaping Differential Evolution Algorithm （MSFL-DEA） to calculate. And the scheme based on AHP and TOPSIS combined weight method is optimized according to different decision preferences. The results show that with the decrease in upstream inflow， the power generation benefit of the reservoir decreases most significantly， followed by the ecological benefit and water supply benefit. Under each inflow frequency， the competition relationship between ecological goal and power generation goal， water supply goal and ecological goal is more obvious， and the competition between power generation goal and water supply goal is relatively weak. Depending on decision preferences， four schemes of water supply priority， power generation priority， ecological priority and balance optimization are obtained. By comparison， it is found that the balanced scheme tends to compromise， and the water supply， ecology and power generation processes are relatively coordinated in each month of the year （P=75% as an example）. When inflow frequency is 50%， 75% and 95%， the annual power generation is 3.697， 2.981 and 2.155 billion kWh， the water supply satisfaction is 0.871， 0.775 and 0.702， and the ecological satisfaction is 0.861， 0.699 and 0.615， respectively. The research results are conducive to improving the efficiency of water resources utilization， and can provide reference for the scientific operation decision of Zaoshi Reservoir.

Flood forecasting is one of the important non-engineering measures for flood control and disaster reduction in the middle reaches of the Yellow River. In this study， a GRU-Transformer flood forecasting model is constructed by coupling gated recurrent units （GRU） with Transformer machine learning models， and rainfall-runoff simulations are conducted to predict flood events in typical sub-basins of the middle reaches of the Yellow River. The predictive results are compared and analyzed with those of the ANN（Artificial Neural Network） and WOA-GRU（Whale Optimization Algorithm Gate Recurrent Unit） neural network flood forecasting models， with a focus on exploring how to better apply the Transformer model to the field of flood forecasting in order to improve the accuracy of flood forecasting in the middle reaches of the Yellow River. The model is established by using historical observed flood data from 1990 to 2016 in the Gu County Reservoir Controlled Basin. The input data includes rainfall data measured at 24 stations and discharge data at the outlet cross-section， while the output data includes flood events under different lead times. The model is calibrated by using 39 flood cases and validated using 10 flood cases. The results of the study show that the GRU-Transformer model has good applicability in flood forecasting， exhibiting higher predictive accuracy in the 1~6 hour lead time flood forecasting， with NSE values of greater than 0.85 in both calibration and validation periods. Its predictive accuracy is better than the WOA-GRU and ANN models under the same lead time， but decreases to a certain extent with increasing lead times. The GRU-Transformer model is more stable and better at predicting flood peaks， showing excellent performance in predicting small flow flood processes and simulating the recession phase of floods. However， it tendes to underestimate flood peaks with longer lead times. Compared with the WOA-GRU and ANN models， the GRU-Transformer model has better robustness， and its predictive accuracy decreases slowly as lead times increases. Hence， the GRU-Transformer model can be used as one of the better flood forecasting methods， providing new forecasting methods and scientific decision-making basis for flood prevention and control in the river basin.

In recent years， extreme weather events have shown multiple and strong occurrences， and extreme hydrological events such as possible maximum floods triggered by extreme weather have posed serious threats to reservoir safety， while the use of conventional flood control scheduling protocols for reservoirs may fail in the face of their threats. Therefore， it is especially important to optimize the regular scheduling protocols of reservoirs and to form emergency scheduling for extreme situations. To address the problem， this paper focuses on the Zipingpu Reservoir， an incomplete regulated reservoir located in the upper reaches of the Min River as the research object， establishes a one-dimensional hydrodynamic model of the river section in the reservoir area based on HEC-RAS， following the “spatial-temporal trade-off” scheduling approach， the optimization principle of “advance pre-release combined with increased release” is adopted， and carries out a study on the scheduling mode of the reservoir in the face of possible maximum floods and the optimization of the scheduling timing with the goal of ensuring the safety of the reservoir and minimizing the downstream risk. It is found that when facing the maximum possible flood with the total influent flow rate of 8 times the reservoir flood control capacity， a reasonable dynamic allocation of the reservoir flood control capacity can be achieved through the combined mode of flood discharge and the joint optimization of the scheduling start and end times， developing an emergency scheduling protocol for the reservoir to cope with the potential maximum flood events. It realizes the reasonable dynamic distribution of reservoir flood control capacity with flood history， and wins more time for reservoirs to complete the flood release task. The optimized scheduling method avoids the hidden danger of conventional scheduling failure， the peak water level in front of the dam during the flooding period is lowered by 18.4 m compared to the original scheduling method， ensure that the water level in the reservoir is always in the safe range； the change of water surface line in the reservoir area is controlled within 14.7 m， which is 55.6% lower compared with the original dispatch， and the overall water level change in the reservoir area is more stable； and the peak reduction rate under the optimized scheme reaches 74%， which minimizes the threat of flooding to the downstream. On this basis， through a further analysis of the definition of reservoir flood control potential， it reveals the reasons for the obvious differences in the flood control effect of reservoirs under the two scheduling methods， and provides new ideas and references for reservoirs to carry out emergency scheduling in the face of extreme floods.

Evapotranspiration is a key factor in hydrological and energy cycles， and its spatio-temporal evolution is influenced by various complex factors such as watershed climate， energy， and underlying surface. The influencing factors of evapotranspiration in different climate regions have spatio-temporal differences and different sensitivity characteristics. Studying the spatio-temporal changes in evapotranspiration is beneficial for revealing the response characteristics of hydrological cycles in complex environments， further deepening people’s understanding of water balance in watersheds， and providing theoretical reference for the rational planning and utilization of water resources in watersheds. Based on the SWH dual source evapotranspiration model， the evapotranspiration and its components of the Poyang Lake Basin from 2001 to 2017 are simulated. On the basis of multi-temporal and spatial scale validation， the spatial-temporal evolution characteristics of the total evapotranspiration （ET）， soil evaporation （Es）， plant transpiration （Ec） and evaporation ratio （Es/ET） of the basin are analyzed. Based on the SOBOL sensitivity analysis method， the sensitive influencing factors and actual change causes of the evapotranspiration components of the basin are explored. The results show that the correlation coefficients between the simulated and measured values of the SWH model at the 8-day scale are 0.92 and 0.89 at the station and watershed， respectively， indicating good simulation results. At the 0.05 significance level， the annual ET in the Poyang Lake Basin does not decrease significantly at the rate of 1.0 mm/a， Es decreases significantly at the rate of 2.6 mm/a， Ec does not increase significantly at the rate of 1.7 mm/a， and Es/ET decreases significantly at the rate of 0.28%/a. The spatial distribution characteristics of Es/ET in the basin are high in the middle and low around， with Es/ET in winter>spring>autumn>summer. Except for summer， Es/ET shows a significant downward trend， mainly concentrated in the southern plain of the lake area and the Xinjiang River basin， accounting for 33.86% of the total basin area. Temperature and wind speed are the main sensitive factors affecting changes in ET and Es in the watershed， followed by precipitation and net radiation. Es is also more sensitive to NDVI. The main sensitive factor for Ec and Es/ET at both annual and seasonal scales is the NDVI， and the significant increase in NDVI is the main reason for the changes in Ec and Es/ET in the watershed.

While China’s economy has progressed exceedingly rapidly， its adverse impact on the environment has been overlooked， thus resulting in numerous issues related to environmental contamination， including water resources pollution. The submersible pusher， due to its diminutive size， facile installation process， and excellent maintenance qualities， is capable of being installed within treatment pools of limited volumetric capacity. By enabling enhanced processing efficiency within each pool， this approach facilitates system-wide efficiency without being subject to the limitations of a singular step’s efficiency. During the procedure of wastewater treatment， the submersible mixer plays a paramount role as one of the essential core components. Its performance and function bear a significant impact on the ultimate quality of the entire sewage treatment process. Hence， the subaqueous propeller has emerged as a crucial apparatus that facilitates the process of amalgamating and propelling fluid within sewage treatment facilities. An integration of experimentation and computational fluid dynamics （CFD） numerical simulation is employed to investigate the various performance indicators， including thrust， power， and thrust-to-power ratio of a submersible thruster operating at a rotating speed of 980 r/min and having a diameter of 400 mm. Additionally， a three-dimensional geometric model is established， followed by the conduction of structured mesh delineation and mesh-independence analysis in order to ensure accurate simulation results. Finally， non-stationary calculations are conducted on the submersible thruster using the aforementioned methodology. Through numerical calculations， it is determined that the submersible mixer equipped with the deflector generated a thrust of 759.33 N， consumed 888.29 W of power， and yielded a thrust to power ratio of 0.85 N/W. Conversely， the submersible mixer without the deflector produced a thrust of 1 003.39 N， utilized 1 144.72 W of power， and resulted in a thrust to power ratio of 0.88 N/W. The present study examines the impact of a deflector on a submersible thruster’s thrust， power， and thrust-to-power ratio. Results indicate that the inclusion of a deflector reduces the aforementioned variables by 24.3%， 22.4%， and 2.4%， respectively， as compared to a submersible thruster lacking a deflector. Through the experiment， it is determined that the submersible mixer equipped with the deflector generated a thrust of 740 N， consumed 903 W of power， and yields a thrust to power ratio of 0.82 N/W. Conversely， the submersible mixer without the deflector produces a thrust of 977 N， utilized 1 164 W of power， and results in a thrust to power ratio of 0.84 N/W. The thrust， power， and thrust-to-power ratio of a submersible thruster with a deflector are reduced by 24.3%， 22.4%， and 2.4%， respectively， for a submersible thruster without a deflector. The discrepancy observed in the comparison of the simulated and experimental measurements of thrust， power， and thrust-to-power ratio falls under 5%， hence confirming the reliability of the experimental results and effectively attesting the precision of numerical simulation. The application of a deflector to the thruster has a positive impact on the thruster's effective propulsive distance. Specifically， when compared to the situation in which a deflector is not applied， the effective propulsive distance increases by 4.8%， 28.4%， and 30.8% at velocities of 0.3， 0.4， and 0.6 m/s， respectively.

In order to dynamically analyze the impact of future land use change on the non-point source pollution load in the watershed，this study couples the PLUS land use prediction model with the SWAT non-point source pollution load model，so as to reveal the distribution of non-point source pollution in the watershed under different land use change scenarios．By taking the Dongjiang Lake Basin as the research area，this paper simulates and predicts the temporal and spatial evolution of non-point source pollution under different land use patterns in the historical series of the study area and in the following 2035 by building the SWAT non-point source pollution model and the PLUS land use model．The results show that the SWAT model has good applicability to the Dongjiang Lake Basin．The Nash–Sutcliffe efficiency index of the river runoff in regular and verification periods are 0.80 and 0.71. Meanwhile，the ammonia nitrogen and total phosphorus rates are higher than 0.5 in both periods．The temporal and spatial evolution characteristics，as well as changing trends，of non-point source pollution in the Dongjiang Lake Basin are studied by using long series simulation results．Non-point source pollution in the Dongjiang Lake Basin is affected by natural processes such as precipitation and runoff and land use patterns. From a time perspective，the pollution output load is concentrated during the high-water period with heavy precipitation. The inter-regional change reveals a trend of non-point source pollution first increasing and then decreasing； from the perspective of spatial scale，higher loads of ammonia nitrogen and total phosphorus are concentrated in the northwestern and central sub-basins with larger runoff and scattered farmland. The impact of different types of land use on non-point source pollution is studied in conjunction with the distribution pattern of land use and non-point source pollution．The contribution degree of total phosphorus load is cultivated land > construction land > grassland > forest land >unused. The land use pattern in 2035 is set by using the PLUS land use model under the historical trend scenario and territorial spatial planning， and the simulation and analysis of the response to non-point source pollution are completed on this basis．Under two different land use pattern scenarios，the territorial spatial planning scenario reduces ammonia nitrogen by 2.12 t and total phosphorus by 54.6 t compared with the historical trend scenario．The former scenario is more beneficial to control the non-point source pollution loads in the Dongjiang Lake Basin．The increase in pollution load is caused by the pollution of farmland， the rapid expansion of construction land and the reduction of forest land，and the restricted conversion of forest land and cultivated land plays an important role in reducing the pollution load of the watershed．

The construction of urban water supply projects in recent years has led to an increasing number of pressured water diversion pipe， and the treatment process of water plants requires the micro-bubbles control of water. Taking the Beikeng Reservoir in Shenzhen as an example， the distribution characteristics of micro-bubble in the pipe are studied by model tests using high-speed photographic image method. The results show that in the working condition with higher energy dissipation rate of the force stilling basin before the inlet of the pressurized pipe， the size of micro-bubbles inside the pipe is smaller and the distribution density is lower. The size of micro-bubbles in the pipe increases and the distribution density increases when the water transmission flow increases from 2.50 m³/s to 5.35 m³/s. The size of micro-bubbles in the pipe changes insignificantly and the distribution density decreases when the water transmission flow increases from 5.35 m³/s to 7.64 m³/s. The test results of micro-bubble control measures show that： the adoption of small flow rate pre-filling， the appropriate installation of exhaust valves， and reducing the diameter of the pipe can control the size and number of micro-bubbles in the pipe effectively. The research results can provide useful reference for similar projects.

Traditional inspection methods for collapsing riverbanks are limited by the scope of monitoring， resulting in limited efficiency and an inability to promptly detect dangerous situations. Extracting water shoreline from satellite images is of great significance to the monitoring and early warning of river bank collapse. Three water body extraction methods based on DeepLabV3+image semantic segmentation technology， traditional NDWI index， and SAR technology are used with Gaofen 1 and 2 satellites， Landsat 8 satellites， and Sentinel-1 satellite images as data sources. This paper discusses the application ability of multi-source satellite data in the identification of river bank collapse， taking the example of the bank collapse with a length and depth of about 100 m in Xiaopan of Jiayu County， Hubei Province in December 2021. The research results show that the domestic Gaofen 1 and Gaofen 2 satellites combined with the DeepLabv3+method can extract the water edge. Through the comparison of different series image， the river bank collapse can be reflected. In the actual work practice， it is recommended to use Gaofen satellite and DeepLabv3+method for automatic water shoreline extraction. In cloudy and rainy weather， SAR method is used to supplement. If necessary， visual discrimination can be carried out manually in combination with the images of the Gaofen satellite and Sentinel-1 satellite.

Towns and cities require wastewater treatment plants to ensure the ecological environment， human health， and sustainable development. It is necessary to predict the future values of the effluent quality indicators of wastewater plants in order to improve the efficiency of urban wastewater treatment plants and optimize energy use. However， due to large number of effluent quality indexes of wastewater plants， the extremely complex reactions involved in the wastewater treatment process， and the high degree of time-series nonlinearity of the data， the mechanistic model based on determining the biochemical reactions and the statistical-based prediction method cannot achieve the desired results. As a solution to this issue， this paper proposes a deep learning-based prediction method for wastewater plant effluent water quality， and a town in Jilin Province has used a CASS process wastewater plant to monitor water quality data at the influent and effluent as the source data， as well as the neural networks combined with the encoder-decoder structure for predicting wastewater plant effluent water quality. The model is also applied to complex environments by adding data on local environmental factors （temperature and precipitation） that affect wastewater treatment. The historical （20 steps） data as the model input to predict the future water quality data. At the same time， to better compare the model performance， this paper divides experiments into short-term prediction （single step） and long-term prediction （20 steps） of two different time dimensions for prediction. Experimental results show that the proposed structure improves the prediction ability of both LSTM and GRU networks， especially the improvement of long-term prediction ability. Based on the ED-GRU model， which has the best prediction effect， the root mean square error （RMSE） of the four effluent water quality indexes of COD， NH₃-N， TP and TN in short-term prediction are 0.755 1， 0.219 7 and 0.073 4， 0.314 6， respectively. The goodness of fit （R ²） is 0.901 3， 0.933 2， 0.916 7， 0.953 2， which can be used to make a better prediction of the local water quality trends. The RMSE of the four indicators in the long-term prediction is 1.720 4， 1.768 9， 0.447 8， 0.831 6， and the R ² is 0.484 9，0.550 7，0.450 2，0.759 5， which can predict the overall trend of future changes in effluent water quality. Compared with the sequential structure GRU， it is predicted that the short-term RMSE will decrease by more than 10%， R ² to increase by more than 2%， and the long-term RMSE will decrease by over 25% and the R ² will increase by more than 15%. Based on the results of this paper， the neural network based on the encoder-decoder structure can make accurate predictions of the effluent quality of wastewater plants and provide technical support for the next step of wastewater treatment process improvement.

In order to investigate the influence of living sand barriers on soil moisture and nutrients in sandy soil， this study selects wheat living sand barriers， alkali grass and oats living sand barriers， and nylon bag mechanical sand barriers in the Qinghai Province’s Gonghe Basin as research objects. Field surveys and indoor measurements are used to compare and analyze the effects of living sand barriers on soil moisture， organic matter content， total nitrogen， total phosphorus， and total potassium in sandy soil. Results show that： ① the soil quality moisture content in the wheat living sand barrier and the alkali grass and oats living sand barrier areas has reached 3.48% and 4.26%， respectively， which are significantly higher than that of the sand drift area （P<0.05）， and are 2.13 times and 2.47 times that of sand drift， respectively. ② Although the organic matter， total phosphorus， and total potassium contents in the soil of the wheat living sand barrier and the alkali grass and oats living sand barrier areas are higher than those of the nylon bag mechanical sand barrier and the sand drift area， they does not reach a significant level （P>0.05）， and only the total nitrogen content in the living sand barrier areas is significantly higher than that of the mechanical sand barrier and the sand drift area. ③ The setting of living sand barriers has a significant improvement effect on soil moisture and total nitrogen content in sandy soil （P<0.05）， which is conducive to the formation of sandy soil and the reversal of desertification.

Ponds are essential elements of both natural landscapes and urban environments， serving as green infrastructures and playing a vital role in contemporary water conservation planning. They provide a wide range of ecosystem services that contribute to the overall health and sustainability of the environment. These services include flood regulation， nutrient retention， mitigation of the urban heat island effect， as well as supporting fish production and aquaculture. Evaluating the significance of ponds by examining their characteristics， determining their priority level for governance and protection， and proposing utilization strategies based on their importance levels are crucial steps in understanding and optimizing their ecological service functions. These efforts form the foundation for effective governance and protection of ponds and ensure their continued contribution to the land ecosystem’s service function and overall effectiveness. By analyzing the land use status of Liaocheng City， an assessment is conducted to understand the characteristics and spatial distribution of pits and ponds. Subsequently， an evaluation index system is developed to determine the importance of these pits and ponds in the region. This comprehensive analysis provides valuable insights into the significance of these water bodies and their role in the local ecosystem. It is found that the distance from the main rivers/lakes and reservoirs is conducive to the migration of Amphibian. The number and area of ponds around cultivated land are much larger than other types of land use. The number of ponds in each district and county decreases according to cultivated land， forest land， rural residential land， and urban residential land. The density of pits and ponds is 3~10 /km²， and the main gathering centers are in the northeast of Dongchangfu District， the middle of Dong’e County and the northeast of Gaotang County.The density and importance of ponds show a trend of high in the north and low in the south， and high in the east and low in the west. To make the most of ponds with high importance scores， this paper recommends strategically utilizing them based on their specific morphology and spatial distribution. This may involve implementing measures such as maintaining their natural features， protecting the surrounding vegetation， and ensuring proper water management practices. On the other hand， for ponds with low importance scores， an ecological reclamation approach can be pursued in conjunction with local land comprehensive improvement plans. By implementing these strategies， Liaocheng City can effectively utilize and protect its pit and pond resources. This will contribute to the preservation of the land ecosystem’s service functions and enhance the overall ecological well-being of the region.

The change of the water level discharge relationship of the hydrometric station reflects the interaction between rivers and lakes. In order to explore the interaction between the Yangtze River and Poyang Lake after the operation of the Long Three Gorges Project， the water level and flow relationship between Jiujiang Station and Hukou Station are analyzed. Based on the water level and discharge relationship considering the backwater jacking effect， the calculation method of water level and flow in Jiujiang and Hukou is established. The research shows that after the Three Gorges Project is put into operation， the water level and flow curve of Jiujiang Station moves down， the average water level for many years is 0.8 m lower than that before the Three Gorges Reservoir is built. The low water level area of the comprehensive line also moves down year by year， and the average water level of Hukou Station decreases by 0.7 m due to the reduction of Jiujiang water level. The influence range of the Three Gorges Project on the main stream of the Yangtze River is above Datong， and the jacking effect of the Yangtze River on Poyang Lake decreases by 1.1%. Based on previous studies， the calculation method of Hukou flow is proposed. The accuracy of the calculation formula of data fitting from 2003 to 2021 reaches 86%. And the relationship curve of water level and flow is established. The discrimination relationship of lake mouth backflow is proposed. When the difference between the flow of Jiujiang River and the flow of Wuhe River exceeds 30 000 m³/s， the Yangtze River water may backflow into Poyang Lake. The research results provide some reference for the analysis of the jacking relationship between the Yangtze River and Poyang Lake.

Since 1956， the Dongting lake basin has experienced a historical process from shrinkage to development. To investigate the reason behind its evolution during each historical stage and predict its evolution trend， we work out this study based on data of water-sediment discharge， lake-basin water surface area and lake capacity during 1956-2019， in which contribution ratios of sedimentation， lake basin subsidence， reclamation and sand mining on lake-capacity variation are identified using the variable separation method. Results show that the lake-basin water surface area decreased by 1 247.59 km² during 1956-2019， in which the shrinkage of the east lake basin was the most severe， and reclamation within the lake basin was the major driving factor during 1956-1980， whereas the lake-basin water surface area became stable after 1980. Both sediment input and output continuously declined before the impoundment of the Three Gorges Dam （1956-2002）， with a rough sedimentation ratio of 70% in the lake. However， sediment input experienced a remarkable reduction after the impoundment （2003-2019）， with the sedimentation ratio falling to 14%. There was an offset effect among lake-basin subsidence， sand mining and sedimentation when they altered the lake capacity. At present， the lake basin is still in a slow tectonic subsidence， with an average rate of 3 mm/a. As sand minning proceeds， the lake shrinkage slows down. Before 1980， the lake capacity decreased， with contribution ratios of reclamation， sedimentation and tectonic subsidence were -92.7%， -13.2% and 5.9%. However， after 1980， the lake capacity witnessed a shift from declination during 1981-2002 to augment during 2003-2019 and a net declination， with contribution ratios of sedimentation and tectonic subsidence were -107.6% and 7.6% during 1981-2002 and those of sedimentation， tectonic subsidence and sand mining were -11%， 24.8% and 86.2% during 2003-2019. Considering the higher rate of tectonic subsidence than sedimentation after the impoundment of the Three Gorges Dam and the dominance of sand mining in the lake capacity change， the Dongting lake will continuously develop as the new sand mining planning （2023-2027） implements.

Mode I fracture tests are carried out on compacted clay specimens containing precast cracks of different lengths， and the fracture mechanism of the soil is analyzed from the macroscopic perspective by combining digital image correlation methods， including load-displacement curves， critical fracture toughness J _IC and horizontal displacement field. The results show that the soil damage mode is independent of the precast crack length， and the load-displacement curves can be divided into compression-density phase， linear change phase and damage phase. The load-displacement curves can be divided into compression-density phase， linear change phase and damage phase； with the increase in precast crack length， the critical fracture toughness J _IC of the specimen decreases linearly； with the increase in load， the local deformation at the tip of the precast crack increases and the horizontal displacement contours gradually converge. The horizontal strain density D _E， which is an index of fine view analysis， is introduced， and it is concluded that the horizontal strain density D _E decreases gradually with increasing precast crack length and is linearly correlated with the critical fracture toughness J _IC.

The water conveyance and power generation system network of cascade hydropower station， which has many types of pipes and joints， is complicated. Traditional calculation programs for the transition process of hydropower station can’t model， determine the topological relationship of pipeline network and calculate it. Aiming at the layout of water transmission and power generation system of series hydropower stations， this paper develops a set of visualization software for modeling and calculation of transition process of multistage series hydropower station based on Qt library. According to the functional requirements of the software and the design idea that each module is independent， the software is divided into three modules： drawing module based on Qt graphics view framework， calculation module based on transient flow and post-processing module for results processing. The three modules are connected with each other， and users manage the three modules through the main interface. Finally， the practicability and correctness of the software are verified by engineering examples.

The bulb tubular unit has been used in many small and medium-sized hydro-power stations in our country. This kind of unit has the characteristics of large inertia time constant of water flow， small inertia time constant of unit and double regulation of guide vane and blade. In addition， the guide vane and blade is in a non-co-linked state during load shedding process， so the characteristics are more complex and the control is more difficult. Especially for many small and medium-sized hydro-power units， the load shedding is often caused by lightning strikes in the flood season， which requires faster stable power operation of the unit， and higher requirements for the control of the transition process of load shedding. In this paper， a nonlinear model of the load shedding transition process of bulb tubular turbine is established. The fixed rotor characteristic curve is used to simulate turbine characteristics. The characteristic line method is used to solve the pressure unsteady flow equation， and the governor equation is introduced， a precise simulation of load shedding transfer process is realized. The load rejection transition process of the actual bulb tubular unit is simulated.The maximum speed increase of the unit under the maximum head is greater than the maximum speed increase under the rated head. Maximum pressure at the inlet of guide vane under the maximum water head is greater than the maximum pressure at the inlet of guide vane under the rated water head. The minimum pressure at the inlet of the draft pipe under the rated head is less than the minimum pressure at the inlet of the draft pipe under the maximum head.The overshoot of unit speed control under rated water head is larger； At the initial of load shedding， the negative water hammer characteristic is obvious. The maximum unit speed at 75% rated load shedding is greater than that at 100% rated load shedding. The maximum pressure at the inlet of guide vane at 75% rated load shedding is close to that at 100% rated load shedding. The minimum inlet pressure of the tailpipe under 100% rated load shedding is the minimum. The research results show that for the bulb tubular turbine， due to the small moment of inertia of the unit and the equal opening lines incline to the right， the bulb tubular unit will produce obvious negative water hammer characteristics in the initial load shedding process， resulting in lower pressure in front of the guide vane and higher pressure at the tail pipe inlet. The minimum unit speed is smaller and the overshoot is larger at the rated head condition compared to the maximum head condition under the same control parameters. Because the escape characteristics of turbine are affected by both guide blade and blade opening， the maximum unit speed may occur in the condition of non-rated head shedding partial load condition rather than 100% rated load under the rated head condition. The research results have a guiding significance for the design， operation and maintenance of bulb tubular turbine.

It is of great significance to study the critical speed of hydro-generator set for its fault diagnosis and structure optimization. However， due to the difficulty of the field test， complex operating and boundary conditions， it is difficult to solve the critical speed accurately. In this paper， a two-guide suspension hydropower unit of a power station is taken as an example. The large general finite element analysis software ANSYS is used as an analysis. Considering the coupling effect of various bearing boundary conditions， a calculation model of bearing dynamic characteristic parameters is established based on fluid lubrication Reynold Equation， and the stiffness and damping of water guide， upper guide and thrust bearing are obtained. On this basis， three dimensional finite element analysis models without mechanical failure， mass eccentricity of rotor or runner and misalignment of coupling flange are constructed respectively. Then the rotor dynamics analysis is carried out by considering the gyroscopic effect. QR Damped method is used to extract the modes， and Campbell diagram is drawn to obtain the critical speed so as to analyze the dynamics characteristics of shafting. The results show that the unit’s flight speed is much less than the first critical speed under normal conditions， and its dynamic performance meets the design requirements. In addition， the critical speed is seldom affected under moderate conditions of mass eccentricity of rotor or runner and misalignment of coupling flange， and the unit can still maintain stable operation.

It is a common problem for hydropower projects， especially for turbine flow parts of hydropower stations， to wear out the sediment in the sandy water， which will lead to the damage of the flow parts， and the hydropower stations have to shut down for repair and maintenance， resulting in huge economic losses. In this paper， the sand wear of pipeline and turbine guide vane specimens developed by the flexible anti-wear material coating is studied. The research findings show that the sand wear of flexible wear-resistant material coatings is much smaller than that of ordinary wear-resistant stainless steel materials， greatly improving the wear resistance of flow components in hydropower engineering. Combined with the test results of the surface velocity of the passing parts， this paper establishes a mathematical model of sediment wear prediction for the overcurrent parts of hydropower projects， which provides a prediction method for sediment wear of similar overcurrent parts of hydropower projects， and also provides technical support for the operation， overhaul and maintenance of hydropower projects， especially hydropower stations.

The analysis of rock slope stability is an important task in engineering geological exploration and design， which mainly includes four parts： the measurement of the occurrence of rock mass discontinuities， the statistics of dominant discontinuities， the analysis of discontinuities stability and the compilation of report. At present， there are the following problems： first， the traditional artificial field measurement method is generally adopted for rock discontinuities measurement， which has the problems of low efficiency， limitation of terrain to measurement range and poor representativeness of discontinuous data. Second， although there is a separate software for discontinuity statistics and discontinuity stability analysis， manual conversion is needed to complete the above two work， which has low efficiency， cannot be analyzed in batches and can make mistakes easily. Third， there is no one-stop software to complete all the above work， let alone automatic generation of analysis reports. To solve above problems， the paper uses Excel-DNA technology to develop a one-stop analysis software for rock discontinuities. This software includes using 3D real model to calculate discontinuance occurrence， discontinuance statistics， discontinuance analysis and report preparation and other functions. Compared with the traditional analysis method， the results are correct and their accuracy is reliable. Using software can effectively improve the standardization level of exploration and design， greatly promote the production efficiency and the quality of results， and has good practical value.

How to choose the direction and proportion of the use of reservoir migrants’ support funds to achieve the maximum efficiency of the use of reservoir migrant support funds is a difficult problem to be solved urgently. Based on the use and implementation effect of reservoir migration support funds in 15 sample counties （cities and districts） in Guangdong Province in 2021， this paper uses the DEA model to calculate the efficiency of reservoir migration support funds. At the same time， environmental factors are taken into account， and the Tobit regression model is used to analyze the environmental factors affecting the efficiency of capital use. The results show that： ① The efficiency of the use of reservoir resettlement support funds in the sample counties varies greatly， among which the pure technical efficiency value is better， and the scale efficiency has become the main factor affecting the comprehensive efficiency， and it is necessary to optimize the scale allocation to improve investment redundancy； ② Among the environmental factors affecting the efficiency of capital use， the improvement of the economic development level， urbanization rate and openness of the permanent population in the sample counties contributed to the improvement of the efficiency of the use of reservoir migrants’ support funds， while the added value of the tertiary industry did not significantly promote the efficiency of the use of reservoir migrants’ support funds.

With the guide vane of the pump-turbine as the main research object， the guide vane opening of 11， 33 and 41 mm is selected to analyze the influence of different guide vane airfoils on runaway characteristics of pump-turbine， so as to provide methods and theoretical guidance for the design and optimization of guide vane airfoil of pump-turbine. The results show that the improved guide vane airfoil has a better improvement effect on the "S" characteristics of the unit under three kinds of guide vane openings. After the improvement of the guide vane airfoil， the internal flow state of the unit is improved on runaway characteristics. The velocity streamlines in the guide vane and runner area are evenly distributed， and the concentrated distribution area of vortex core is reduced. After the improvement of guide vane airfoil， the relative value of pressure pulsation amplitude of monitoring points in vaneless area at different openings decreases in different degrees， and the velocity pulsation curve is gentle and the velocity peak value is smaller than before the improvement. The concentrated distribution area of vortex core in the draft tube of the improved guide vane airfoil is reduced， and the unit can operate in a relatively stable state.

Taking a power station in Lancang River Basin as an example， this paper uses a mathematical model and physical model to calculate and analyze the influence of different characteristic water levels on the sedimentation distribution at the end of the reservoir after the construction of the reservoir for the preliminary proposed schemes of different normal storage water levels and the operating water level during the flood season. The result shows that the accumulated siltation in the reservoir area increases with the increase in the operating water levels during the flood season and the normal storage water levels， and the influence of the operating water levels during the flood season is relatively large. The siltation distribution at the end of the reservoir presents a slight increase in siltation on the edge beach surface compared with the natural situation. The research results can provide a basis for reservoir characteristic water level selection and ecological protection.

The process of resettlement in reservoir areas is a long one， involving a wide range of areas， and it is difficult to control investment. The problem of overestimating the investment in resettlement often occurs. Therefore， how to effectively control the investment in resettlement in reservoir areas has become an urgent problem to be studied. This paper analyzes the main factors affecting the reservoir resettlement investment from three aspects： external project environments， project subjects and project participants. It quantifies the comprehensive effect degree of the factors influencing the reservoir resettlement investment through DEMATEL-ISM model， and analyzes the hierarchical structure and overall impact relationship of different factors. The research shows that： There are 8 cause factors and 9 result factors among the 17 influencing factors of resettlement investment. ISM divides the set of influencing factors into 6 layers and 3 categories. Among them， land expropriation for construction and immigration scale， changes in physical quantity of immigration， implementation progress of resettlement， contract management and communication among project participants are direct influencing factors， while policy adjustment is an important influencing factor. Finally， according to the calculation results of the model， the authors put forward some suggestions： strengthening the fundamental influencing factors， paying attention to the intermediate influencing factors， and implementing the direct influencing factors， so as to provide a reference for the more accurate and effective control of the investment in reservoir resettlement.

In order to explore the influence of the staggered impeller on the pressure fluctuation characteristics of the double entry two-stage double suction centrifugal pump， this paper uses the method of combining experiment and numerical simulation to carry out a research on the same pump with symmetrical impeller and staggered impeller as the contrast scheme， and quantifies the pressure pulsation characteristics of the suction chamber， inter-stage flow channel and volute under three typical working conditions of 0.6Q， 1.0Q and 1.2Q. The results show that： ① in terms of external characteristics， the head and efficiency of the pump with staggered impeller are higher than those with symmetrical impeller at all working conditions， and they can be 2% and 3% higher than those at 1.0Q working condition. ② In terms of pressure pulsation characteristics， for the suction chamber， the influence of staggered impellers on pressure pulsation is small at all working conditions， and the difference of dominant frequency amplitude is less than 2%. For the inter-stage flow channel， the staggered impeller can restrain the pressure fluctuation at all working conditions. For example， the dominant frequency amplitude at the tongue of the inter-stage flow channel can be reduced by 13.5% compared with that of the symmetrical impeller. For the volute， the staggered impeller can improve the pressure fluctuation under all working conditions. For example， the dominant frequency amplitude at the tongue of the volute can be reduced by 31.9% at most. This finding can provide a reference for the application of staggered impeller in double inlet two-stage double suction centrifugal pump.

The purpose of this paper is to investigate the effect of the bent pipe inlet on the solid-liquid two-phase flow characteristics of centrifugal pumps through Mixture multiphase flow model and ANSYS software， and to conduct a full-flow channel numerical simulation of centrifugal pumps under three different inlet conditions with solid-liquid two-phase flow as the medium in order to obtain more accurate results. The analysis focuses on the distribution of solid particles movement in the centrifugal pump inlet section and the flow characteristics inside the impeller. The study shows that the synergistic effect of inlet bend and solid particles makes the head and efficiency of centrifugal pump have a significant decrease， with the increase in the inlet bend angle， solid particles will be concentrated towards the external wall surface of the inlet section and the end of the suction surface of the vane， the most obvious effect when the inlet bend is 60?. At the same time， the study shows that appropriate to increase the bend angle can reduce the centrifugal pump tongue radial force， but in the solid-liquid two-phase conditions， with the increase in the bend angle of the centrifugal pump internal pressure pulsation will have a greater impact.

For the water intake construction using conventional construction methods by environmental conditions and geological conditions constraints， and environmental pollution， long construction period， high construction investment， the need for large equipment and ships and other problems， the construction technology creatively changes the traditional first inside and then outside the construction sequence， through the pre-buried underwater closed steel pipe to replace the rock plug body， water access time is not subject to the flood lag， the use of floating box water platform for taking the mouth of the pipe trough underwater excavation， pre-buried steel pipe sinking in place， underwater concrete encapsulation fixed take the mouth of the steel pipe and seepage， shore restoration and a series of process measures， with pre-buried steel pipe replacement of the rock plug body， not only to ensure the quality of the mouth of the penetration， construction safety， normal operation of the reservoir storage and the construction area surrounding environment and existing structures basically no. The construction area is not only safe but also has no impact on the surrounding environment and existing structures.

When the downstream stilling basin of the sluice flows freely at the end sill， the downstream river bed water depth h _t is often less than the corresponding critical water depth h _k，and the hydraulic calculation of stilling basin cannot meet the requirements of the hydraulic design of relevant sluice design specifications. At present， the hydraulic calculation method of the stilling basin with free discharge is not perfect， which brings great inconvenience to the engineering design. Based on the summarizing of the research results of the downstream stilling basin of the sluice， and under the assumption that the downstream river bed depth h _t of the stilling basin with free discharge is equal to the critical depth h _k，the calculation method of the tail height of the stilling basin with free discharge is discussed，the corresponding calculation method is put forward. The results are verified by the hydraulic model test， which has the characteristics of convenient calculation， and can be used as a reference for similar engineering design and operation.

It is one of the most effective ways to reduce pipe network leakage by controlling pipe network pressure. Traditionally， the pressure reducing valve is only applicable to the pressure management of local pipe network. In this paper， the method of real-time regulation of the pressure reducing valve and the water supply pump station is used to manage the pipe network pressure. Based on the systematic analysis of the response relationship and characteristics between the leakage amount and the node pressure， a hydraulic model of pipe network leakage is established.Taking the water supply network in CYN District of a city in North China as an example， genetic algorithm （GA）， particle swarm optimization （PSO） and whale optimization algorithm （WOA） are used to solve the case， and then the operation effects of these three algorithms are compared and analyzed. The results show that the whale optimization algorithm has better performance for solving the leakage model.

With the commencement of many water transfer projects， it is important to study the safety of control radial gates in water transfer projects. Through a comparative analysis of the causes of the radial gate vibration， it is found that the probability of the radial gate vibration of the water transfer project is not lower than that of the high dam radial gate. Based on a practical case， the vibration prototype observation and vibration elimination measures of the radial gate of the water transfer project are explored. Through vibration displacement， vibration displacement （amplitude） and frequency relationship， vibration stress multi-parameter comprehensive analysis of the gate vibration in the safe range. Through an analysis of the causes of vibration， the emergency vibration removal measures of fine tuning the oil cylinder on one side of the gate under the operating conditions are proposed. The magnitude of the gate vibration is significantly reduced， and the maximum vibration acceleration can be reduced by 621%. The analysis thinking and emergency vibration elimination measures of gates can serve as a reference for similar projects.

Based on the daily meteorological data from 21 meteorological stations during 1961-2020， the crop water requirement ET_c， effective precipitation P_e， irrigation requirement IR， and irrigation requirement index IRI in the Nanpan River Basin with 60 years （1961-2013） are calculated by using the Penman-Monteith equation and single crop coefficient method， the temporal and spatial variation of ET_c， P_e ， IR，and IRI during Citrus sinensis Osbeck growth season in different regions are analyzed by the linear trend estimate and M-K method. The results show that the ET_c， P_e and IRI of Citrus sinensis Osbeck in Nanpanjiang River Basin are 902.22~1 042.70 mm， 289.62~477.68 mm and 0.48~0.71 respectively. The ET_c and IRI had increase with an increasing rate of 2.171 mm/decade and 0.9%/decade. The P_e significant decrease with a decreasing rate of 8.538 mm/decade. The rising trend of ET_c and IRI is mainly concentrated in the southwest and central South of Nanpan River Basin， and the decreasing trend of P_e is mainly concentrated in the middle and east of Nanpan River Basin. The ET_c of Citrus sinensis Osbeck in the Nanpan river basin is represented as fruit expansion stage>flower season>fruit coloring stage>dormancy period>flower bud differentiation stage>mature picking period. The P_e is ranked as fruit expansion stage>fruit coloring stage>mature picking period>dormancy period>flower season>flower bud differentiation stage. The IRI is ranked as flower season>flower bud differentiation stage>dormancy period>fruit expansion stage>fruit coloring stage>mature picking period. In different growth periods of Citrus sinensis Osbeck in Nanpan River Basin， ET_c and IRI are high in the southwest and low in the northeast. The high value area of increase is mainly distributed in the southwest， the high value area of decrease is mainly distributed in the northeast， while Pe is completely opposite.

Surveying， as an important leading course in the core courses of multiple intelligent water conservancy majors， is the foundation and starting point for the cross integration of water conservancy majors and new surveying and mapping technologies. In the context of the "Double First Class" construction in the school， this article comprehensively analyzes the goals of cultivating intelligent water conservancy talents and the problems in the teaching of surveying courses. It absorbs and draws on the teaching experience of basic courses in advantageous disciplines， and proposes a reform idea of restructuring surveying teaching content in a specialized mode， expanding surveying basic theory， merging and compressing traditional instrument practice teaching， and introducing new intelligent surveying technology. By organizing open experimental courses and combining them with online teaching platforms， We aim to address the issues of insufficient teaching capacity and hours， as well as the evaluation of teaching effectiveness， in order to cultivate intelligent water conservancy talents with solid theoretical foundations， broad academic perspectives， and comprehensive professional skills. The ideas proposed in the article provide reference and reference for the construction of smart water conservancy surveying courses.

This paper aims at exploring the tolerable water depth and duration of submergence for early rice during the heading and flowering stages in the Poyang Lake Basin. To this end， four main early rice varieties planted in the basin are selected for submergence tolerance tests during their heading and flowering stages， and the findings are summarized as follows. The plant height of each treatment increases or is compared with that of control group after flooding stress. Submergence stress during the heading and flowering stages are linked to rice yield reduction， whereas submergence depth and duration are correlated with effective panicle number， seed setting rate and 1 000-grain weight. Moreover， different varieties also present different submergence tolerance， e.g.， Taiyou 398 and Xiangzaoxian 45 are considerably adaptable to submergence stress. Taking rice yield reduction ≤10% as the acceptable standard， the tolerable water depth of submergence for Zhuliangyou 171 and Zhongjiazao 17 during their heading and flowering stages is 1/2 of their plant height， while the tolerable duration of submergence is 1~3 days. Contrary to the above， the tolerable water depth of submergence for Xiangzaoxian 45 is 2/3 of its plant height， while the tolerable duration is 1~3 days. Moreover， Taiyou 398 demonstrates impressive submergence tolerance， boasting a tolerable water depth of 2/3 of its plant height and a 3~6 days tolerable duration.

In order to simulate the operating status of the irrigation networks with pipe conveyance under different working conditions， this paper presents a numerical simulation model based on the mass conservation law and energy conservation law of constant flow. In this model， the equations of hydraulic state are established respectively to indicate the irrigation networks with pipe conveyance by using the bisection method to solve the equations respectively， the simulation results include the actual working points of the main nodes of the pipelines and the outlets， and the actual flow rate， head， power and efficiency of pumps. The case analysis shows that the model converges rapidly under the condition of each rotational irrigation schemes， the simulation results provide an important basis for water management of the system and the optimization of the engineering designs， which reflects a good practical application value.

According to the shallow instability characteristics of channel expansive soil in cold and arid regions， the dry-wet and wet-dry freeze-thaw cycle tests of channel expansive soil in the north bank of Yili River are designed to simulate complex climate environment and direct shear tests under low stress conditions. The attenuation law of shear characteristics of channel expansive soil， such as shear strength， cohesion and internal friction angle， is discussed with the cyclic mode and dry density. The results show that with the increase in normal stress， the attenuation degree of shear strength decreases， and the decrease in dry density decreases the effect of shear strength deterioration. The attenuation rate of shear strength of samples after the initial wet-dry freeze-thaw cycle accounts for more than 40% of the total attenuation degree. After five cycles， the attenuation degree of cohesion of samples under the wet-dry freeze-thaw cycle is about 20% higher than that under the dry-wet cycle. Within a certain range of compaction， the greater the dry density of the sample is， the smaller the attenuation degree of cohesion and the greater the attenuation degree of internal friction Angle. The superposition of “squeezing” and “crack” effects should be taken into account when the increasing or decreasing law of shear strength index is analyzed. S1WDFT and S2WDFT are set as dangerous conditions in the initial construction and operation of the channel foundation soil， and the function of the variation of shear strength index with the number of wet-dry freeze-thaw cycles is fitted.