To effectively solve the high-dimensional problem of water resources carrying capacity classification and evaluation， and reveal the dynamic changes in water resources carrying capacity， an improved projection pursuit clustering model is proposed. For the improved projection pursuit clustering model and the projection pursuit clustering model based on the maximum information entropy principle， the reasonable range and optimal value of density window width were derived by analyzing the negative entropy change law of projection values； When the density window width is the optimal value， the improved projection pursuit clustering model performs better in classification evaluation than the projection pursuit clustering model based on the maximum information entropy principle. This article uses an improved projection pursuit clustering model to dynamically evaluate the water resources carrying capacity status in Jiangsu Province. The water resources carrying capacity level from 2009 to 2020 and 2022 was level III， and the water resources carrying capacity level in 2021 was level II. A grey GM （1，1） model was established to predict the water resources carrying capacity status of the province as level II from 2023 to 2030. The improved projection pursuit clustering model more effectively extracts the structural feature information of high-dimensional data for water resources carrying capacity evaluation indicators， further enhancing the accuracy of the water resources carrying capacity classification evaluation model and making the evaluation results more objective and reasonable. Through comparative analysis of the contribution rates of indicators in 2022 and 2009， the measures taken by the province to save water in industry and agriculture， accelerate socio-economic development， and protect water resources have promoted the continuous improvement of water resources carrying capacity. Based on the contribution rate of evaluation indicators to the water resources carrying capacity status and evaluation standards in Jiangsu Province， this paper deeply analyzes the shortcomings of the water resources carrying capacity in the province， and puts forward relevant suggestions to improve the water resources carrying capacity status， ensuring that the water resources system carrying capacity status in Jiangsu Province reaches level I as soon as possible and achieving sustainable utilization of water resources.

Copula function is used to model， and P-III distribution is used to fit the marginal distribution function of the inflow runoff of two important reservoirs， Yunlong Reservoir and Songhuaba Reservoir， which are responsible for Kunming water supply in the Jinsha River Basin on three time scales （annual， flood season and non-flood season）. The joint distribution function of the fitted marginal distribution function is constructed， and the K-S test method is used to test the goodness of fit of the joint distribution function. Graphic analysis and calculation method， AIC criterion and BIC criterion are used to fit and optimize the joint distribution function. Finally， the optimal Copula function is used to analyze the wet and dry encounters of the two reservoirs on three time scales. Main results are as follows：the optimal Copula function of the annual and non-flood season inflow runoff of the two reservoirs is Gumbel Copula function， and the optimal Copula function in flood season is Frank Copula function. The sum of the synchronous probability of the two reservoirs on the three time scales （0.734 in the whole year， 0.541 in the flood season， and 0.728 in the non-flood season ） is greater than the sum of the asynchronous probability of the two reservoirs on the three time scales （0.266 in the whole year， 0.459 in the flood season， and 0.272 in the non-flood season）. Among all the wet/normal/dry combinations， the probability of wet/wet of the two reservoirs is the highest in all the combinations （0.310 in the whole year， 0.232 in the flood season and 0.308 in the non-flood season ）， indicating that the two reservoirs are the most likely to be wet years in all the combinations. The probability of dry/dry of the two reservoirs on the time scale of the whole year and the non-flood season （0.298 in the whole year and 0.296 in the non-flood season ） is not much different and both are greater than the probability that the two reservoirs are dry and dry on the time scale of the flood season （0.232 in the flood season ）. Therefore， in the actual operation of the two reservoirs， especially in dry years， the wet-dry synchronization of the two reservoirs should be considered. The results of this study can provide some decision-making reference for the joint optimal operation of reservoir groups in the Jinsha River Basin.

In order to solve the problem that the input field of existing urban inundation models in simulation and calculation usually only considers rainfall and related parameters set in advance， and cannot incorporate the actual waterlogging data into the model to correct the simulation results in real time， resulting in a significant deviation between the model calculation results and the actual situation， a real-time correction method for urban inundation models based on equivalent water volume method is proposed by using the model calculation results and waterlogging monitoring data for real-time assimilation to determine the production and drainage coefficients in the model. Taking the urban waterlogging simulation mathematical model of Shijiazhuang City as an application case， a typical rainstorm case is selected to verify the effect. The results show that the simulated waterlogging values after real-time correction can better reflect the actual waterlogging situation. The consistency index between the simulated value and the actual value increased from 0.72 before the correction to 0.96 after the correction， significantly improving the calculation accuracy of the model through the correction technique.

China is rich in total water resources， but there are still problems such as low per capita water resources and uneven spatial and temporal distribution of water resources， which are more obvious in arid areas. China is currently implementing the most stringent water resource management system， which， despite its effectiveness to a certain degree， has not been able to effectively address the water resource challenges faced by arid zones. This paper summarizes and analyzes the water resources management policies and legal documents involved in China's arid zones from the institutional level， using structural-functional analysis method. The results of the analysis show that： ① the water resources management system in China's arid zones has a positive function of regulating water resources utilization behavior and improving water resources utilization efficiency， and a latent positive function of promoting water-saving technological innovation and sustainable development， as well as a latent negative function of water resources allocation that may lead to the solidification of power and an imbalance in supply and demand， and that the management system increases the cost burden on enterprises and individuals. ② China's water resources management system in arid zones has a vertical structure constraint of legislative norms， a horizontal structure constraint of water resources management systems， and a combined horizontal-and-vertical structure constraint of authority allocation. Further analysis shows that the structural constraints mentioned above are due to the vertical handicap of the water resources management legislation， the limitations of the horizontal configuration of the water resources management system， and the unclear distribution of responsibilities in the operation of the water resources management system， which leads to difficulties in the implementation of the system in the field of water conservation， irrational allocation of water resources， and the low efficiency of the utilization of recycled water， as well as the problem of overlapping responsibilities among the main bodies of the water resources management， thus restricting the operation of the system of water resources management. Therefore， in response to the above problems， special water conservation legislation should be formulated， the water resources management system in arid zones should be improved， and the distribution of responsibilities and rights in water resources management should be clarified， with a view to optimizing the structural obstacles and systemic deficiencies of China's water resources management system in arid zones and eliminating the effects of its potential negative functions.

The Hanjiang River is the largest tributary of the Yangtze River and also the water source of the Central Line Project of South-to-North Water Diversion Project and the Hanjiang-To-Weihe River Water Transfer Project. It has an important strategic position. Scientifically assessing the response of its water cycle under changing environments such as climate change and human activities is of great significance for the sustainable use of water resources in the basin and the formulation of appropriate management policies. In this paper， a calibrated VIC distributed hydrological model was constructed with the Hanjiang River Basin as the research area. Then， based on the downscaled global climate model data and land cover remote sensing data in different periods， different scenarios were simulated to comprehensively analyze the response law of water cycle elements in the basin under changing environment， and quantify the contribution rate of climate change and land use to runoff changes. The results show that under different climate change scenarios， the average annual precipitation in the middle and upper reaches will increase significantly， and the precipitation during the year will be more concentrated in the wet season of summer and autumn. The actual evapotranspiration in each month will increase as a whole and the distribution within the year will be more uniform. The inflow of Danjiangkou reservoir and the runoff at the outlet section of the basin will show a significant increasing trend in RCP8.5 scenario. The flow in the dry season of the basin will decrease during the year， and the annual proportion of flow in the wet season will increase by a maximum of 8.51%. The future monthly flow will be more concentrated in the wet season. And the probability of drought and flood disasters will increase. Some savannas and woodlands in the Hanjiang River Basin have been transformed into deciduous broad-leaved forests with higher canopy density since the 21 st century. Land use change has not significantly changed the interannual variation trend of flow， but it has reduced the flow as a whole. The contribution rates of climate change and land use to the inflow change of Danjiangkou reservoir in different periods are 80% ~ 88% and 12% ~ 20% respectively， and the contribution rates to the change of flow at the outlet section of the basin are 72% ~ 88% and 12% ~ 28% respectively. Climate change is the main driving force of runoff changes in the Hanjiang River Basin.

The rational allocation and effective utilization of flood control storage capacity of cascade reservoirs play a crucial role in flood control and disaster reduction and comprehensive benefits of reservoirs in flood season. Aiming at the problem that there is no effective method to distinguish the importance of each reservoir on the overall flood control safety in the process of flood control capacity allocation of cascade reservoirs， which leads to the unreasonable allocation of flood control capacity， this paper combines the nonlinear safety degree of reservoirs with the variable weight considering the characteristics of reservoir inflow， design flood control capacity and propagation time from discharge to flood control station， and proposes a calculation method of reservoir flood control safety degree based on variable weight nonlinear safety degree. At the same time， considering the safety of cascade reservoirs and downstream flood control stations， the goal is to maximize the overall flood control safety degree of cascades and minimize the excessive flood volume of downstream flood control stations. The optimal allocation model of cascade flood control capacity based on safety degree is constructed， and the differential evolution algorithm is used to solve the model to realize the optimal allocation of flood control capacity. The method is applied to the allocation of flood control capacity of cascade reservoirs in Wudongde， Baihetan， Xiluodu and Xiangjiaba reservoirs in the lower reaches of the Jinsha River. The results show that compared with other methods， this method can describe the dynamic change process of the weight of each reservoir without reducing the overall flood control effect of the cascade. By increasing the use of flood control capacity of Wudongde and Baihetan reservoirs， the use of flood control capacity of Xiluodu and Xiangjiaba reservoirs is reduced， and the flood control safety of the cascade as a whole during the scheduling period is maximized. This method can reflect the differences in the importance of each reservoir in cascade flood control， realize scientific management and reasonable allocation of flood control storage capacity among reservoirs， and provide a basis for scientific decision-making on reservoir flood control optimization operation.

The jacking effect of Xiajiang Reservoir construction on the water level of the main stream of the Ganjiang River mainly affects the hydrological regime change of the upstream Ji?an section. It is of great significance to analyze the water level changes caused by the jacking effect of backwater and analyze the cause mechanism of water level rise in the river section to study the flood control and disaster reduction work of water conservancy project construction to change the hydraulic characteristics of the river channel. Based on the historical measured water level and flow data， this paper constructs a stepwise regression prediction model to calculate the effect of water level jacking. Pearson correlation analysis is used to quantitatively evaluate the correlation and influence degree between the effect of water level jacking and various factors. Then， the stepwise regression method is used to quantitatively analyze the effect of Xiajiang Reservoir operation on Ji?an water level jacking， that is， the multiple regression equation between the effect of water level jacking and various factors is established and the reliability of the equation is verified. The results show that： ① The prediction model based on stepwise regression analysis has high simulation accuracy， and the simulation results of water level and flow factors are good. The simulated water level process is basically consistent with the measured process. In terms of simulated flow， the measured process can also be well reproduced， and the evaluation indexes of the water level prediction model are better than those of the flow prediction model. ② The effect of water level jacking has a strong positive correlation with the measured water level of Xiajiang Reservoir， a moderate positive correlation with the measured water level of Ji 'an and the falling process of Ji?an water level， a moderate negative correlation with the measured flow of Ji?an， and a weak negative correlation with the rising process of Ji?an water level. ③ The modified determination coefficient R² of the multiple stepwise regression equation is 0.892， which indicates that the equation has a high fitting degree and passes the subsequent accuracy test. It can characterize the multiple driving effects of the measured water level， the measured flow， the measured water level of Xiajiang Reservoir and the water level fluctuation process in Ji?an.

As a relatively stable component of river runoff， baseflow is also the main source of runoff during dry season in arid and semi-arid areas， which is of key significance to the optimal allocation of water resources and the maintenance of ecological environment in the basin. The accuracy of baseflow separation results has a great influence on the prediction of hydrological processes in the basin and the investigation of baseflow change rules. As an important tributary of the middle reaches of the Yellow River， the Fen River is related to the economic development of the whole middle reaches area， and the study of baseflow change of the Fen River can effectively characterise the change mechanism of the baseflow in the middle reaches of the Yellow River， so it is particularly important to select the appropriate separation method. There are many baseflow separation methods， among which numerical simulation method is widely accepted in practical application because of its objectivity， repeatability and ease of operation， as well as efficient and convenient processing of long series of lengthy and complicated data. Based on Jingle hydrologic station daily runoff data from 2006 to 2014， eight commonly used numerical simulation methods are used to separate the base flow， and the intra-annual and inter-annual variation characteristics of the runoff are analyzed. The characteristics are analyzed from three perspectives： the base flow index of instability coefficient， standard deviation and coefficient of variation； we also study the correlation of base flow index in typical years of base flow and runoff process. To test the validity of the base flow separation results， three indexes are selected：Nash-Sutcliffe efficiency coefficient， the average relative error and the correlation coefficient. The results show that： The Chapman filtration method， the Chapman-Maxwell filtration method and the Eckhardt filtration method proved to be the most suitable methods for separating base flow at the Jingle hydrological station. The calculated BFI values are 0.491， 0.495 and 0.496 respectively. The results of the study provide technical support for the study of baseflow separation and change rule of baseflow in the middle reaches of the Yellow River， and provide scientific basis for the rational use of water resources in the middle reaches of the Yellow River and better construction of the local ecological environment.

In 2022， a large drought occurred in the Yangtze River Basin， which was widespread and long-lasting and had a major impact on agriculture， ecology and other aspects. Precipitation decreased compared to the same period， and the temperature increased， leading to a decrease in soil water content and the synchronization of agricultural drought occurrence. Reviewing the development process of this agricultural drought in the Yangtze River Basin and exploring its meteorological causes are of great significance in improving the understanding of the drought occurrence mechanism and realizing an effective response to the drought. In this study， based on ERA5 data， the main soil water content characteristics of the 2022 agricultural drought are revealed from the spatial and temporal dimensions by comparing the soil water content in 2022 with the average values of the same period in many years； the severity of this agricultural drought is clarified by comparing it with the previous drought events using the standardized soil moisture index values； and， finally， the meteorological causes of this drought are analyzed from the perspectives of atmospheric circulation and sea-surface temperatures （SSTs） of the external forcing field. The analysis showed that in 2022， the agricultural drought degree in the whole basin from June to September was： no drought， extreme drought， extreme drought， and extreme drought， respectively. The basin suffered three months of extreme agricultural drought， of which August had the deepest drought based on numerical judgment. In terms of the meteorological causes of drought， the influence area and intensity of the Western Pacific Subtropical High （WPSH） increased from June to September 2022 compared with the same period in previous years， and the position of the WPSH was abnormally westward， almost including the entire range of the basin， resulting in the basin as a whole being under the control of the WPSH alone； at the same time， the summer precipitation in the Yangtze River basin was closely related to the SSTs in the northern part of the Atlantic Ocean and the northern part of the Pacific Ocean in the previous fall/winter， as well as to the SSTs in the eastern part of the Pacific Ocean， Atlantic and Indian Ocean in the same year's spring/summer， and there is a discrepancy between the SSTs during the high correlation period and the mean values of the previous periods， causing the related droughts.

Dyes are widely used in production and daily life， leading to frequent dye pollution in the environment， especially in water bodies， which poses potential risks to ecosystem and human health. Biochar has a wide range of sources and meets the requirements of “dual carbon”， and is widely used in environmental pollution control. However， due to its poor adsorption capacity and lack of selectivity， modification is the most commonly used method to improve its sorption capacity. In order to improve the adsorption of crystal violet （CV） by biochar， magnetic biochar modified with cobalt-zinc ferrite （Co_0.5Zn_0.5Fe₂O₄@BC） was prepared from orange peel by coprecipitation-pyrolysis method. X-ray diffraction （XRD）， scanning electron microscope （SEM）， Fourier transform infrared spectroscopy （FT-IR）， specific surface area and pore size analyzer （BET） and Zeta potentiometer were used to characterize the biochar before and after modification. The experimental results showed that Co_0.5Zn_0.5Fe₂O₄@BC produced mesoporous structure， which significantly increased the specific surface area of the material. Moreover， the surface positive charge of the material is increased， and the pH adaptability of the material is improved. Thus， it promoted the adsorption of CV by biochar. The effects of different experimental conditions on the adsorption of CV by modified biochar were investigated through batch experiments. The adsorption kinetics and isotherm were fitted using different models. It was found that the adsorption capacity of Co_0.5Zn_0.5Fe₂O₄@BC for CV was significantly improved， and the removal rate reached 99.64%， which was significantly improved compared with the raw biochar （41.94%） and Co_0.5Zn_0.5Fe₂O₄ （26.78%）. The first-order kinetics and Langmuir model better fit the adsorption process and adsorption isotherm. The adsorption process was monolayer adsorption， mainly physical adsorption， and the maximum adsorption capacity was 227.59 mg/g. The modified biochar could effectively adsorb CV at pH 5~11. Common co-existing cations and anions slightly promoted the adsorption of CV by modified biochar. The adsorption performace was better in tap water and Yangtze River water than pure water， which shows that the material has a good anti-interference ability. After 5 cycles， the removal rate of CV can still reach 69.75%. This study provides a potential material for the treatment of CV polluted water. It also provides a new approach for the adsorption of dye wastewater by biochar modification.

Based on the measured topographic data in the lower reaches of the Beijiang River （Shijiao-Sanshui） in 1998， 2012 and 2020， a systematic study was conducted on the spatiotemporal changes of the river terrain over the past 20 years. A two-dimensional hydrodynamic and water quality coupling numerical model was then established for the study area using the finite volume method， aiming to quantitatively investigate the spatial distribution of the hydraulic retention time under different terrains and flood magnitudes. The results indicated that there existed significant erosion in the river channel from 1998 to 2012， with an average elevation decrease of 2.9 m in the entire study area and 7.8 m in the thalweg， showing a notable trend from wide and shallow to narrow and deep in the river section. From 2012 to 2020， the average elevation of the study area decreased by 0.7 m， while the average elevation of the thalweg increased by 0.4 m. Both changes were significantly lower than those between 1998 and 2012. Correspondingly， the morphology of the river section tended to stabilize. The spatial distribution of the hydraulic retention time in the study area showed a gradual increase from upstream to downstream， and the time in the center of the river was generally lower than that on both banks. Under the same terrain conditions， larger flood magnitudes usually corresponded to the shorter hydraulic retention time in the study area， suggesting a faster transport speed of the substance. Under the terrain conditions in 2020， the hydraulic retention time at the outlet position under P = 1% design flood was 11.99 hours， which was lower than 12.69 hours under P = 5% design flood and 13.08 hours under P = 20% design flood. From the time scale perspective， the average hydraulic retention time in the study area increased by 0.72~0.75 hours between 1998 and 2020， and the hydraulic retention time at the outlet location increased by 2.20~2.35 hours. By comparing the hydraulic retention time at the outlet location with the average flow velocity at various hydrological stations， it was found that there existed a significant negative correlation between the two. Therefore， a power function was finally used to estimate the hydraulic retention time， and the proposed formula had a good fit. The results of this article could provide scientific reference for the early warning and management of sudden pollution incidents in the lower reaches of the Beijiang River in the future.

As an important component of territorial land space， river shoreline is an important link for material exchange and energy conversion in aquatic and terrestrial ecosystems， and has unique ecological service value. Mastering the diversity characteristics and influencing factors of shoreline utilization structure is an important foundation for rational utilization and scientific management of shoreline space. This study selected 16 representative rivers in Zhejiang Province and divided them into into 4 major categories and 16 subcategories， accroding to their shoreline functions. The total number of shoreline utilization units is 4 905. The total length of the shoreline units is 4 580 km. There are 1.07 units of shoreline length per unit. The classification types of shoreline functional areas along different river are basically consistent. The number and length of artificial and natural shorelines are generally equivalent. And the degree of utilization of river shorelines is extremely high （the utilization area accounts for 96.3%）. There are certain differences in the intensity and refinement in the utilization of different river shorelines， with Cao'e River being the highest and Xiaoxi River being the lowest. There are significant differences in the diversity of shoreline utilization types among different rivers， with Xin'an River being the highest and Aojiang River being the lowest. The distribution pattern of the quantity and length of different shoreline types in the same river remains highly consistent， showing a strong positive correlation （ρ=0.973）. Rivers are divided into 4 groups according to the presence or absence of shoreline types. There are 14 strong self-similarity on the left and right banks of the same river， and the number of river groups with moderate similarity or above in pairs accounts for 64%. The diversity of shoreline utilization types is mainly negatively correlated with the natural characteristics of rivers （basin area， river length， average river width， slope）， while positively correlated with social attributes （unit population， unit GDP）. Zhejiang Province is one of the most economically developed regions in China. River shoreline space plays an important role in the development of national economy and society. Conducting research on the structural composition and influencing factors of shoreline utilization types and proposing relevant suggestions can help enhance the value of waterfront space resources， promote the optimization of national spatial resources， and strengthen the protection of water shorelines.

The accuracy of water quality simulation in the BOD-DO model is significantly influenced by the values of its parameters. In order to enhance the inversion accuracy of the BOD-DO water quality model parameters， this study firstly constructs a multi-parameter inversion model based on the Dobbins-Camp BOD-DO water quality model. The objective of the proposed model is to simultaneously determine the optimal values of the oxygen consuming coefficient （K ₁）， aeration coefficient （K ₂） and BOD settling and rising coefficient （K ₃） in the Dobbins-Camp BOD-DO water quality model by minimizing the discrepancies between the calculated and measured values of BOD and DO concentrations. Then， to overcome the challenges associated with the Sparrow Search Algorithm （SSA）， such as low solution accuracy， insufficient stability， and easily falling into local optima in the SSA， three strategies are introduced： a combination of Sine chaotic mapping with opposition-based learning， transition probability， and differential variation. These strategies are designed to improve the diversity of the initial population， expand the search space， and enhance the population's ability to escape local optima respectively. Based on these improvements， a Multi-strategy Improved Sparrow Search Algorithm （MISSA） is proposed for solving the established Dobbins-Camp BOD-DO water quality multi- parameter inversion model. Finally， numerical experiments are conducted to evaluate the effectiveness of the MISSA by comparing the inversion results obtained from MISSA with four intelligent optimization algorithms： Sparrow Search Algorithm， Simulated Annealing Algorithm， Particle Swarm Optimization， and Genetic Algorithm，. Additionally， the impacts of observation noise and initial values on the inversion results are discussed. The results show that the computational performance of the MISSA algorithm significantly surpasses that of the four algorithms in the control group. Moreover， it can effectively reduce the influence of initial value selection on the inversion results of the BOD-DO water quality model parameters. When the noise level of observed data does not exceed 5%， the MISSA can effectively improve the stability of the inversion results. The results confirm the effectiveness of the MISSA in inverting the parameters of the Dobbins-Camp BOD-DO water quality model， and can provide a valuable reference for solving water quality model parameters.

Dredging in rivers and lakes can cause sediment suspending and make water turbid. In order to control the environmental pollution by dredging， attempts have been made to use bubble curtains to block the sediment， and on-site and indoor experiments have been conducted. Comparing the changes in sediment concentration at fixed measuring points with and without bubble curtains， the interception effect of bubble curtains on natural sediment and kaolin particles was explored. Based on this， the concept of turbidity interception rate by bubble curtains was proposed. The spatial and temporal variations of sediment concentration behind the bubble curtain were measured， and the influence of aeration rate per unit width on the turbidity interception rate of the bubble curtain was analyzed. The experimental results show that the bubble curtain has a certain turbidity interception effect， its turbidity interception rate being 0.8 for natural sediment and over 0.4 for kaolin particles. With the increase of the aeration rate per unit width， the turbidity interception rate of bubble curtains increases and then decreases. The bubble curtain has good applicability in controlling the diffusion of dredging sediment and， especially when used in combination with silt curtains， can further reduce the diffusion amount of suspended sediment while allowing free passage of ships in the dredging area.

The problem of eutrophication of water bodies is becoming increasingly serious，a phenomenon that leads to an abnormal growth of phytoplankton and the release of harmful algal toxins，which contribute to the pollution of water bodies and pose a risk to flora， fauna and even humans. Related to this， water bodies are often slow-moving， poorly connected and have long stagnation times， making them more vulnerable to eutrophication and increasing the risk of blooms. In this paper， the impacts of hydrodynamic factors， water environment factors and meteorological factors are discussed in depth. Hydrodynamic factors include water velocity， flow rate and water disturbance， which together determine the degree of algae accumulation； water environment factors include water temperature， dissolved oxygen， nutrient salt concentration and pH， which directly affect the growth of planktonic algae； meteorological factors such as air temperature and wind will change the temperature of the water body， which will have an impact on the formation and development of the bloom. This paper also discusses the application of numerical model and data-driven model in the prediction of water bloom based on the characteristics of water bodies of rivers， lakes and reservoirs. Numerical model is used in the prediction of water bloom to predict the occurrence and development trend of water bloom by simulating the environmental factors in the water body； the data-driven model is based on data mining algorithms and statistical techniques， and uses the machine learning method to iteratively learn the correspondence relationship between the monitoring data and pictures and the bloom by analysing and identifying the monitoring data and pictures. correspondence， and iterative learning to create their predictive links with the outbreak of waterwaters. They provide an effective tool for exploring the condition of water bodies and predicting water bloom events， and their coupled approach is of great significance for the accurate prediction of water bloom， which is also the development trend of future research， and will help water resource managers to better regulate the water body， and improve the prediction accuracy and the efficiency of water quality management in order to reduce the occurrence of water bloom.

The adhesive spawning fish eggs adhere to the gravel surface or gravel gap， and hatch in shallow pits near shore， which have specific requirements for hydrological conditions in spawning grounds. After the complementary operation of hydro-wind-solar， the peak regulation of hydropower causes a greater fluctuation in the subdaily downstream flow， which can lead to the exposure and drying of adhesive-spawning fish eggs in the air， affecting the hatching rate of the eggs. Most existing ecological flow research lack quantitative studies on the alteration rates of interday flow， and the coordinated scheduling of hydro-wind-solar often lacks consideration of the suitable flow for fish reproduction. This paper proposes a new method for evaluating the subdaily flow variation by calculating the overlap ratio of suitable habitat areas under different flow conditions from the perspective of fish reproductive demands. Furthermore， by comprehensively considering the consumption of new energy and changes in hydrological conditions caused by hydropower peak shaving， a hydro-wind-solar ecological cooperative scheduling model oriented to the reproductive needs of adhesive-spawning fish is proposed. Taking the lower reaches of Yangqu Dam as an example， the results indicate that in order to meet the reproductive needs of fish that lay adhesive eggs， the maximum hourly flow rate alteration should not exceed 120 m³/（s·h）. Compared with the peak shaving scheduling scheme， the ecological scheduling scheme reduces the consumption of new energy by 7% and 6% respectively during normal and dry periods， and reduces hydropower output by 2% and 6% respectively. However， the change in hydrological conditions is reduced by 15% and 21%. The research results can provide technical support for the optimization operation of hydropower ecological scheduling during the spawning period of adhesive-spawning fish， and promote the sustainable development of hydropower.

“Infiltration” is the first technical element of sponge city， and urban green land is an important component of sponge city construction. Research on soil infiltration performance of urban green land can provide scientific support for the construction of urban “sponge body” in Changzhi. In this paper， the surface soil infiltration process of the typical built-up residential areas in Changzhi is measured by the field single ring infiltration method， and the influence of soil physical properties on surface soil infiltration is discussed. The adaptability of three commonly used infiltration models in this area is evaluated. Based on the optimal model， the overflow time of the green land under different average rainfall intensity is calculated. The results show that the overall infiltration capacity of green land in Changzhi is fairly good， with the stable infiltration time ranging from 50 to 100 min and the stable infiltration rate ranging from 0.109 to 3.633 mm/min， and the stable infiltration of green land in old residential areas is the fastest. Spatial heterogeneity of soil physical and chemical properties are common. Infiltration parameters are negatively correlated with bulk density and initial water content， but positively correlated with field water capacity and saturated water conductivity. The Horton model is more suitable during the process of soil infiltration in the green land of Changzhi with changing over time. When the stable infiltration rate of the green land is 0.10 mm/min and the initial infiltration rate is at a high level， the overflow time will gradually shorten with the increase of the average rainfall intensity. If the initial infiltration rate is at a low level， the risk of waterlogging will increase further. Therefore， the spongy reconstruction can be carried out for green space.

Prestressed concrete cylinder pipe （ PCCP ） plays an important role in China 's water diversion projects. The safety of PCCP operation is very important to the allocation of water resources and is related to the national economy and people 's livelihood. When harmful cracks occur on the inner surface of the core concrete， the inner core concrete will be damaged under the action of water pressure， resulting in the corrosion of the steel cylinder and the formation of safety hazards. Therefore， research on the prevention and control of concrete cracks on the inner wall of the core is of great significance to the rational utilization of water resources. In order to prevent and reduce harmful cracks on the inner wall of PCCP， according to the research results of scholars at home and abroad， the types and forms of concrete cracks on the inner wall of PCCP core are summarized， including longitudinal cracks， spiral cracks and socket cracks. The relationship between factors such as drying shrinkage， settlement shrinkage， temperature shrinkage， welding seam， winding stress， hoisting and transportation， and concrete cracks on the inner wall of PCCP is summarized. The prevention and control methods of cracks in the inner wall of PCCP core are summarized from the aspects of PCCP design， raw materials， mix ratio， maintenance system， weld， steel cylinder， socket and crack self-healing， fiber reinforced materials and so on. Finally， the control and prevention of cracks in the inner wall of PCCP core concrete are prospected， which provides ideas for further research.

The strongly permeable stratum of waterfront is always accompanied by high groundwater characteristics， which is prone to cause many hazards and adverse effects on the construction of foundation pits in this stratum. It is necessary to use curtain and tube well seepage prevention and lowering measures. The evaluation methods of seepage prevention and lowering effects of curtain and tube well are still in the exploration stage. In this paper， ABAQUS finite element calculation software is used to research the seepage characteristics of the pit under the action of curtain and tube well respectively. Single-width seepage volume， curtain precipitation depth and slope water level are used to evaluate the curtain seepage control effect， and tube well flow rate and slope water level are used to evaluate tube well precipitation effect. Then sensitivity analysis is conducted on the curtain depth and distance of curtain from the pit， as well as the tube well depth， tube well spacing and tube well radius. In addition， the effect of curtain and tube well on seepage control and precipitation under the joint action of curtain and tube well is analyzed. The results can provide a design basis for the arrangement of curtain and tube well in the ship lock foundation pit project.

The optimum grinding time is obtained by experiments on the effect of different mechanical grinding time on the characteristics of molybdenum slag. The molybdenum slag under the action of this grinding time is used as an admixture to prepare cement-based materials， and the effects of different molybdenum slag content on the mechanical properties， pore structure and other properties of cement-based materials are analyzed. The results show that when the content of molybdenum slag is 30%， the performance of cement-based materials is the best. The best grinding time is 2.0 h， and the various properties of molybdenum slag reach the best state. Appropriate addition of molybdenum slag can effectively improve the pore structure of cement-based materials and make cement-based materials more dense. Excessive addition of molybdenum slag will destroy the microscopic pore structure of cement-based materials， which will lead to the reduction of the properties of cement-based materials. At this time， the cement-based materials still maintain good strength and can meet the needs of practical engineering， but the cost is increased from the economic point of view， which is not conducive to the progress of the project.

Prestressed anchor-cable and cast-in-place pile combination support structures effectively leverage their respective advantages and are increasingly applied in foundation pit reinforcement. This study employs the three-dimensional finite difference method to simulate the entire process of staged excavation and support for the Guiping Navigation Hydropower Station Expansion Project foundation pit. The study analyzes the stress and deformation characteristics of the combined support structure of prestressed anchor cables， anchor rods， and anti-slide piles， and validates the rationality of the numerical simulation through monitoring data. The results indicate that for foundation pit slopes with soil at the top and rock at the bottom， embedding a combined structure of anti-slide piles and prestressed anchor cables into the underlying bedrock can effectively control the plastic failure and deformation of the upper soil slope. Additionally， combining prestressed anchor cables with random anchor rods can effectively curb the lateral displacement of the lower rock slope. The pile-anchor combination support structure exhibits excellent applicability and reinforcement effects for foundation pits in mixed soil and rock strata.

GPR technology has been widely used in many fields in recent years， but it can‘t detect water-filled cavitation in road release detection in highway engineering， and it has never been applied in the detection of bag slope protection project. In view of this， this paper studied the influence of the moisture content of the bag on the wave velocity and the relative dielectric constant through laboratory model tests， and analyzed the changes of electromagnetic wave wavelength in the mold bags. The velocity， wavelength， attenuation constant and skin depth of electromagnetic wave in water with different conductivity were studied and analyzed by pool model test. The results show that in the detection of the mold bag slope protection project， high frequency antenna should be selected as far as possible to improve the resolution of steel bar， and the influence of water content of the bag should be mainly considered， and accurate relative dielectric constant should be selected to accurately calculate the position of steel bar. In water-filled cavitation detection， the attenuation of electromagnetic wave in water should be considered， and the attenuation degree of high frequency band depends on the conductivity of water. When the conductivity of water is less than 0.1 s/m， the bottom of the void layer can be detected by high frequency antenna. When the water conductivity is greater than 0.1 s/m and less than 1 s/m， it is difficult for high frequency antennas to recognize. When the conductivity reaches 1 s/m， all frequencies in the high band can′t be recognized.

During the construction of earthwork cofferdam seepage control wall， solid wall mud has certain seepage control function. If some emergencies occur in the project that seriously affect the construction progress， in order to ensure the construction progress of the main building， the project can use the construction strategy of pit pumping in advance during the construction of cofferdam impermeable wall. But at this time， the impermeability of the solid wall mud and the stability of the weir body to meet the requirements remain to be studied. In this paper， ABAQUS finite element calculation software is used to research the influence of depth of impermeable layer of cofferdam， mud permeability coefficient and mud influence zone on the seepage control ability of cofferdam by taking seepage volume as evaluation parameter. On this basis， the inversion method of mud permeability coefficient based on the seepage flow volume of cofferdam is proposed， which provides an important basis for the research on the construction strategy that the construction of cofferdam impermeable wall is carried out at the same time with the advance drainage of foundation pit. The research results can provide reference for similar projects.

Aiming to address the challenge of difficult lifespan prediction for durable metallic structures like hydraulic steel gates， a methodology based on digital twin technology is proposed. This approach seeks to acquire life cycle data for the gates to enable accurate prediction of remaining useful life. Initially， a digital twin of the hydraulic steel gate is established using finite element modeling. Real-time static and dynamic response characteristics of the radial steel gate are obtained through a monitoring system. Building upon this foundation， vibration frequency and structural stress are utilized as responses. Bayesian theory is then employed to perform real-time uncertainty model adjustments to the gate， based on the responses. Ultimately， by utilizing the refined high-fidelity model， a dataset encompassing the gate's entire lifecycle is generated， enabling accurate prediction of the remaining useful life of the gate. The outcomes of this study indicate that the responses corresponding to the adjusted parameters exhibit smaller deviations from actual responses compared to initial simulation values. Moreover， the predicted remaining useful life results closely align with the actual predictions within a 95% confidence interval for real lifespan forecasts. This underscores the effectiveness and feasibility of the proposed methodology.

Flood storage and detention area is an important part of the flood control engineering system， and the transfer road is an important channel for flood control and emergency rescue， as well as for the safe transfer of people during flood diversion in flood storage and diversion area. The layout of transfer roads in flood storage and diversion area involves many issues such as the number of transferred population， road length and transfer time. To study and solve the problem of planning the layout of transfer roads in flood storage and diversion areas， this paper introduces road interference coefficients and establishes a planning and layout model for transfer roads based on the principle of flood risk map and flood avoidance transfer model. A total of 20 transfer units from 7 embankments， including Xiangcheng Embankment， Qukou Embankment， and Xinnong Embankment in the Dujiatai flood storage and diversion area， were selected to calculate the time required for the layout and transfer of trunk and branch roads by using the transfer road planning and layout model. Based on the preliminary plan of the transfer road layout and length， the time required for transfer is 0.74~5.15 hours， which is less than the available transfer time； The road network density of transfer roads is calculated for the seven embankments with determined transfer routes， and the calculated road network density of embankments is 0.44~0.92km/km²， which can meet the requirements of specifications. The results show that the model can conveniently determine the layout and length of the trunk lines and branch lines of transfer roads in flood storage and diversion areas， and quantitatively calculate the transfer time required for the safe transfer of transfer units to resettlement sites. The model can serve as a reference for the planning of transfer roads in flood storage and diversion areas.

The strain localization failure problem of geotechnical granular materials widely exists in engineering design applications. Its main manifestations are strain localization at the mesoscale and shear band generation at the macroscale， and their microscopic mechanism is still currently unclear. In order to systematically study the formation and evolution of strain localization in particle aggregates， a true triaxial test with designated plane strain loading path is simulated using discrete element method （DEM）， which provides thorough insights into the material geometry， motion， and mechanical information of granular materials on both micro- and macroscopic scales. To identify the optimal feature quantity for characterizing strain localization characteristics， micro indicators such as particle temperature， fluctuation displacement， and local dilatancy angle are compared with each other. It is found that the fluctuation displacement has better correlation with other parameters in characterizing strain localization， so it is selected as the strain localization characterization variable. In order to quantify the specific axial strain level from the onset of strain localization in particle aggregates to the completion of development， the Moran’s I is introduced to statistically analyze the spatial distribution characteristics of displacement fluctuation， and the shear band development interval of particle aggregates during the elastic-plastic transition stage is determined. Furthermore， before the strain localization of particle aggregates fully developed， the spatial distribution and the probability density function （PDF） evolution of displacement fluctuation indicates that the plasticity out of research region ceases to evolve in the transition stage， while the plasticity in research region increases in the mode of percolation. Finally， a cluster model describing strain localization on mesoscopic scale is obtained through clustering analysis based on the spatial distribution of displacement fluctuation. This model can link the formation and development of macroscopic shear bands in particle assembly with the microscopic plastic development of individual particles， depicting the evolution process of particle sample from onset of strain localization on mesoscopic scale to fully developed macroscopic shear bands.

Data-driven models have been widely used in the fields such as dam operation state modeling and short-term deformation prediction， while the existence of outliers in the monitoring data can weaken or even destroy the credibility and robustness of data-driven models. Aiming at the above problems， a coupled DWT-IFLOF dam monitoring data anomaly detection algorithm is proposed. First， a wavelet noise reduction technique is used to reduce the negative interference of monitoring data centralized collection noise on model modeling. Secondly， a new monitoring data anomaly metric expression coupling the isolated forest （iForest） anomaly detection algorithm with the normalized local outlier factor value （LOFnor） is designed. Finally， by introducing the Lajda criterion， the outliers are qualitatively screened based on the calculated outlier scores. The experimental results show that， compared with some popular anomaly detection algorithms， the detection rate is improved by more than 18.32%； the accuracy rate is improved by more than 20.14%； and the accuracy rate is improved by more than 0.71%. It can effectively detect anomalies in dam safety monitoring data.

This study aims to explore the feasibility of estimating the content of water-soluble soil ions by combining multispectral remote sensing technology with soil physicochemical properties. The research area is situated in the saline soil regions of southern Xinjiang， where the concentrations of major water-soluble cations and anions （K⁺、Na⁺、Ca²⁺、Mg²⁺、HCO₃ ^-、Cl^-、SO₄ ^2-） were measured. Machine learning algorithms such as Random Forest （RF）， Gradient Boosting Regression （GBR）， and Extreme Gradient Boosting （XGBoost） were employed to construct soil ion content inversion models based on remote sensing spectral features and soil information. Additionally， the study compared the estimation accuracy of models incorporating soil variables with those that did not. Results indicate that when only multispectral remote sensing data were used as input variables， all three models could only differentiate between high and low levels of soil ion content， with limited ability to accurately estimate the concentrations of individual ions. Incorporation of soil variables into the models significantly enhanced estimation accuracy. Among the methods used， the RF model exhibited the highest prediction accuracy， followed by XGBoost， and GBR had the lowest accuracy. Regarding the estimation of specific ions， the concentrations of Mg²⁺， Ca²⁺， and Na⁺ were predicted with relatively high precision and model performance was stable； SO₄ ^2-， Cl^-， and K⁺ showed moderate performance with quantitative prediction capabilities； whereas HCO₃ ^- content estimation was only feasible to a certain extent with the GBR model. Optimal models varied for different ions， with the RF model providing the best inversion results for K⁺， Mg²⁺， and Cl^-； the XGBoost model excelling in the inversion of Ca²⁺， Na⁺， and SO₄ ^2-； and the GBR model performing well for HCO₃ ^- inversion. Notably， the optimal relative analysis errors for Mg²⁺， Ca²⁺， and Na⁺ content estimation were 2.829， 1.951， and 1.870， respectively， indicating that these models are highly reliable for estimating the concentrations of these ions. The findings of this study provide a scientific reference for the regional-scale estimation of major ion concentrations in soil salinity within arid regions.

Quantitatively describing the irrigation water transformation mechanism in multi-water source irrigation areas in southern China is of great significance in efficient use of water resources in irrigation district. In this study， taking the Yangshudang watershed in Zhanghe irrigation district in Hubei Province of China as a case and considering the spatial difference of irrigation sub-regions， the irrigation and drainage systems were horizontally and vertically generalized， and an irrigation water balance simulation model in ditch-canal-pond-reservoir system was constructed based on the water balance principle. Meanwhile， according to the measured daily water depth of typical ponds and internal reservoirs from 2021 to 2022， the Latin Hypercube Sampling method and Partial Correlation Analysis method were used to conduct sensitivity analysis on model parameters， and the model was calibrated and validated on different watershed scales. The results showed that the range of Nash-Sutcliffe Efficiency （NSE） was between 0.72 and 0.99 in both scenarios， the Root-Mean-Square Error （RMSE） was both within 0.20 m， and the Mean-Absolute Error （MAE） was not more than 0.14 m， which indicates the process of water conversion within the irrigation system can be described effectively by this model. Compared with traditional distributed water balance simulation models for irrigation district， this model can describe the water transformation process in the irrigation area more comprehensively while satisfying high accuracy， providing a new approach for quantitatively describing the water transformation process in the irrigation system within the basin.

Soil water movement parameters are necessary input parameters for quantifying soil water retention and movement process. Unsaturated water conductivity， specific water capacity and accurate acquisition of relevant model parameters determine the calculation accuracy of the basic differential equation， and then determine the fitting accuracy of the soil water movement model. This paper takes 65 loess sampling points as the research object， and constructed a BP neural network prediction model of soil water characteristic curve and unsaturated water conductivity of undisturbed loess， based on the conventional physical and chemical parameters of soil. The results show that it is feasible to obtain soil water movement parameters by using the BP neural network model. The constructed model has good prediction effect on both training samples and verification samples， the relative error of the training sample is less than 6.4%， and the relative error of the verification sample is less than 5.7%. The research results have important theoretical value for promoting the development of soil hydrodynamics theory， agricultural soil water management and hydrological forecasting theory， and have important practical value for improving the level of agricultural water resources management.

In order to explore the path to achieve the water-saving goal and improve the water use efficiency， in this study， the contribution of the construction and management of water conservancy projects to the water-saving strategic goal was analyzed in large and medium-sized irrigation districts. Taking Jiangsu Province as an example， six typical irrigation districts were selected and statistical data from 2015 to 2022 were collected. The water-saving potential of canal engineering， field engineering and non-engineering measures was calculated respectively，and the total water-saving potential of the irrigation district was calculated accordingly. Taking project investment， labor input， land input and technology progress of water conservancy projects as independent variables and the total water saving potential of irrigation districts as dependent variables， the C-D production function was improved to construct a “two-log model”. Multiple linear regression was performed on the data by SPSS software， the optimal equation was established after removing irrelevant variables by stepwise method， and the contribution rate of different variables to the water saving goal was calculated by elasticity coefficient. The results showed that among the total water-saving potential components， the proportion of water saving in canal system was the largest， and the proportion of water saving in field engineering was the smallest. The average contribution rates of water conservancy projects， land and technological progress to water conservation goals were 45.5%， 30.4% and 5.2%， respectively. However， the contribution rate of technological progress showed an increasing trend year by year， and the contribution of water conservancy projects decreased first and then increased. The contribution rate of water conservancy projects in large irrigation districts was higher than that in medium-sized irrigation districts. This study applies the C-D production function model to the evaluation of water conservation， and the results are reasonable and reliable， which can provide a technical reference for the development of water conservation in large and medium-sized irrigation districts.

The pumped storage power station is an important part of the power grid， and the long time deviation of the pump turbine from the optimal operating condition will lead to hydraulic instability problems， among which the vortex band and pressure fluctuation of the draft tube are concerned， which seriously affects the safe and stable operation of the unit. Taking pump-turbine as the research object， the characteristics of the flow in the draft pipe and the time-frequency characteristics of pressure pulsation are analyzed in this paper. The visualization effects of two second-generation vortex identification methods and two third-generation vortex identification methods on the evolution process of draft tube vortex zone are compared. The Omega-Liutex vortex identification method has less dependence on threshold value and is more clear and complete in recognizing the shape of vortex zone. Therefore， the transient change characteristics of draft tube vortex zone under different load conditions are studied by using the Omega-Liutex vortex identification method. The research results can provide some theoretical reference for the stable operation of pump turbines.

To address the issue in the application of critical chain technology in current construction progress control， where the buffer calculation method is rough and the buffer management method is disconnected from the actual construction progress. This paper constructed a buffer zone optimization model by introducing five factors： the risk control coefficient， resource impact coefficient， process complexity coefficient， process location coefficient and environment， and by using the Analytic Hierarchy Process and CRITIC （Criteria Importance Through Intercriteria Correlation） objective weighting method；a dynamic monitoring mechanism for the buffer zone is established by relating the buffer zone consumption rate to the completion progress percentage of the project work chain. The buffer zone optimization model and the dynamic monitoring mechanism are used to improve critical chain technology， which is applied to the construction progress management of pump station projects. The results show that the size of the buffer zone obtained by this method is relatively reasonable， which can shorten the planned construction period and realize dynamic monitoring of the buffer zone， and provide a reference for the construction progress control of water conservancy projects.

To effectively predict potential equipment failures during the production and operation of pump station projects and enhance the operational efficiency of pump station equipment， this study proposes a HMM-MLP fault prediction method for pump station equipment based on the digital twin hydraulic engineering data platform and existing hardware equipment， and guided by the structural fault mechanism. First， continuous wavelet packet transform is used to process the equipment operation signals. Then， the HMM model is used to generate the state sequences of devices' operation， serving as inputs to the MLP network to predict equipment failures. Finally， simulation experiments demonstrate that the HMM-MLP model significantly improves the accuracy of pump station equipment fault prediction. Additionally， leveraging online monitoring data and offline inspection and test data， a health assessment index system for equipment is established. And a pump station monitoring health diagnostic system is developed to assist operational managers in fully understanding and monitoring the “health” status of unit equipment， thereby enhancing the informatization level of equipment management. Practical results indicate that this research provides practical guidance and experiential insights for the construction of pump station health systems.

In order to study the influence of different cross-section shapes of volute on the performance of large double-suction centrifugal pump， in this paper， three different volute schemes are designed for transient numerical simulation， keeping other factors remain unchanged. The results show that under the design working conditions， the efficiency of the circular volute is the highest， which is 90.7%， followed by the pear-shaped volute， which is 90.2%， and the efficiency of the rectangular volute is the lowest， which is 88.9%. And the high-efficiency area of the circular volute has been expanded. The energy loss rate of the circular volute is the least under each flow condition. The energy loss rate of the circular volute is 0.3% and the energy loss rate of the rectangular volute is 1.1% under the design condition. Under large flow and design flow， the radial force of the impeller with circular volute is the smallest， followed by the pear-shaped volute， and the rectangular volute is the largest. Under the design conditions， the three volute schemes show periodic changes in the pressure pulsation on the volute， and the amplitude of the pressure pulsation at each detection point of the circular volute is the smallest.