This paper analyzed the pre-stressing mechanism of the steel wire and the damage process of the pipeline， and proposes a method of PCCP wire broken warning and alarm threshold assessment based on mechanical simulation analysis. The PCCP finite element model was established by ABAQUS program， and the complete construction process including laying bedding， installing pipelines， backfilling in steps was simulated， and the stress state of pipeline prestressing steel wires， steel cylinders and pipe core concrete was calculated under nearly 100 working conditions with different depths of burial and different design working pressures. It was proposed to take the maximum permissible number of broken wires of the pipe core concrete cracked under the action of water hammer as the early warning threshold for the bursting of the pipeline， and the maximum permissible number of broken wires in the limit state of the buried bearing capacity of the pipeline as the alarm threshold for pipe bursting， and analyzed the relationship between the PCCP wire broken warning and the alarm threshold under different working pressures and burial depths.

The hydraulic design of the impeller blade and guide vane was carried out for the super-large flow submersible tubular pump device with Q=100 m3/s， and the optimization was carried out based on the orthogonal test method. The optimal pump device scheme was calculated by CFD to explore the external characteristics of the unit， and the hydraulic performance parameters of the two types of guide vane installation units with flush and uneven exit edges were compared and analyzed. The research results show that when the impeller hub ratio is 0.4， the number of blades is 4 and the number of guide blades is 6， the efficiency of the pump unit is the highest， and the maximum efficiency of the pump unit is 80.52%. Under the working condition of 1.0Q _d， the pump head is 2.73 m and the efficiency is 74.68%. Under the working condition of 0.87Q _d， the pump head is 4.50 m， and the efficiency is 80.14%. Under the 1.12Q _d working condition， the pump head is 0.45 m and the efficiency is 23.77%. From the parameters of head， efficiency and hydraulic loss of guide vane section， it is concluded that the hydraulic performance of the unit with uneven guide vanes placed at the water edge is better. The modeling method of impeller and guide vane and the optimization method combined with orthogonal test and CFD calculation have improved the hydraulic optimization efficiency and are suitable for popularization and application. Moreover， the research results of the calculation and analysis of the low head and super-large flow pump also provide a certain hydraulic performance reference for the large-scale development of submersible tubular pump.

Cavitation phenomenon and hump instability characteristics are the main factors affecting the safe and stable operation of the centrifugal pump unit. In this paper， based on the numerical calculation and model test results of two impeller schemes of a large centrifugal pump unit， the cavitation performance and hump instability characteristics were comparatively analyzed to explore the correlation between the two. At the same time， the hump generation mechanism and the role that cavitation performance played in it were analyzed.The numerical results show that due to cavitation， a hump instability phenomenon appears on the H-Q performance curve in the numerical results. In addition， the impeller with excellent cavitation performance has a uniform pressure distribution on the blade surface in the small flow area and a reasonable minimum pressure distribution， and its hump instability characteristics are significantly improved. The model test results show that under normal operating conditions of the pumping station， by increasing the ratio of plant cavitation coefficient σ_p to incipient cavitation coefficient σ_i， the hump margin increases when the impeller cavitation performance is improved. The results show that there is a positive correlation between cavitation performance and hump instability characteristics. The improvement of impeller cavitation performance in the small flow zone reduces the degree of cavitation， the flow in the impeller passage can be improved， hydraulic efficiency can be increased and hump instability characteristics can be improved. The study results provide design reference for the safe operation of large centrifugal pump.

In order to investigate the effect of water surface evaporation abatement and water saving benefits under different floating coverage conditions， PE bottles， HDPE balls， and plastic film panels were used as test materials， and three different water surface coverage rates were set to carry out two consecutive annual non-glacial large-scale evaporation pool tests in the central arid zone of Ningxia， to comparatively analyze the evaporation abatement rates， water surface temperatures， changes in water quality， and water-saving costs and benefits of different covering materials and coverage rates. The results show that： the evaporation abatement rate of covering materials tends to increase from April to June， and tends to decrease from July to October； under the same conditions， the evaporation rate of the three types of cover of HDPE balls is 42.14%， 56.56%， 70.15%， which is significantly higher than that of PE bottles and plastic film panels； with the increase of the coverage rate of the material， the water body warms up more obviously， and plastic film panels have the greatest impact on water temperature， followed by HDPE balls， and PE bottles； no toxic substances were found in the covered water body and the water quality is stable and getting better. Under the same coverage， the water saving cost of HDPE balls is the lowest， and that of plastic film plates is the highest： with the same coverage material， 50% coverage is the lowest， 75% coverage is the highest； the value of direct benefits of the three materials to eliminate water surface evaporation is negative， but taking into account the indirect benefits of the case， if HDPE balls are used to cover 10 000 m² of water surface， the lifetime coverage rates of 50%， 75%， and 90% can realize positive benefits of 259 400 yuan， 274 100 yuan， and 360 600 yuan， respectively. After a comprehensive consideration of water-saving effect， water-saving costs and benefits， HDPE ball is identified as the water-saving material that can be used to reduce water surface evaporation in arid areas.

Compared with traditional spur dike， permeable spur dike have more excellent stability， safety and reliability， so they have been valued in the promotion of green channels. The purpose of this study is to compare the changes of three-dimensional flow structure in different curvature channels， and then provide basis for river regulation with different curvature. The research uses a combination of numerical simulation and actual measurement to compare， select and verify three turbulence models： Standard k-ε， RNG k-ε， and Realizable k-ε. The correlation coefficients between simulated velocity and measured velocity in the inner bank of Standard k-ε， RNG k-ε， and Realizable k-ε turbulence models are lower than those in the outer bank. The correlation coefficients between measured velocity and simulated velocity in RNG k-ε turbulence model are the highest. Finally， RNG k-ε turbulence model is used to simulate the 90° and 180° bend， and to analyze the three-dimensional streamline， velocity， bed shear and water surface line. The results show that the vortex axis in the downstream region of the spur dikes inclines to different degrees under the influence of vertical and radial velocity gradients. Two vortices in opposite directions are generated between the spur dikes when the current strikes No.2 spur dikes， which will threaten the structural stability of the permeable spur dikes， but at the same time prevent a large amount of sediment from depositing between the permeable spur dikes and ensure that the permeable spur dikes will not lose their permeability during use. The increase of river curvature leads to the migration of strong shear layer to the inner bank， and two strong shear layers appear in the 180° bend， which will lead to the evolution of river bed to step type. For the mountain river with large curvature and narrowness， the erosion effect of inner bank should be evaluated after arranging permeable spur dike to prevent the migration of strong shear layer from posing threat to inner bank. The water surface line is low inside and high outside， and in the range of x/L=0.48~0.5， the difference between the water surface line inside and outside is the smallest， and the water surface appears concave.

The head loss substitution method with setting resistance rings is adopted in general physical model of long distance pressurized water diversion projects. Based on the hydraulic model test of Shenzhen Beikeng reservoir water diversion tunnel project， the head loss substitution effect and its variation law of the resistance ring under different Reynolds number， ring numbers and arrangements show： If Reynolds number （Re） is bigger than 0.32 \times {\mathrm{10}}^{\mathrm{5}}， it has less influence on local coefficient of head loss of the resistance ring and length of vortex region behind resistance ring； the decrease of parameter d/D （the diameter ratio of orifice and pipe） and the increase of the parameter L/D （the ratio of distance between rings and diameter of pipe） will enhance the head loss substitution effect； if parameter d/D is 0.8， L/D is 0.5， and the number of rings n is bigger than 2， the average local head loss coefficient K_d decreases with the increase of parameter n， and K_d does not change with the number of rings if the parameter n is bigger than 20. On this basis， the fitting curve between the ring number influence coefficient ε and the ring number n， the formulas of the total local head loss in the resistance substitution section and the length of the substitution pipe is derived. By analyzing the influence of different ring number on the length of vortex region， the length of transition section no less than 2.5D should be set behind the resistance substitution section to ensure the flow pattern returns to the unsubstituted state.

Because the thermal conductivity of freezing soil is hard to measure， in order to clarify the influence of temperature on thermal conductivity， a hyperbolic model with three parameters was proposed to describe the relationship between thermal conductivity and negative temperature in this paper. Then， the performance of the new hyperbolic model was verified by the measured thermal conductivity coefficients and three widely used models， and a sensitivity analysis of model parameters was performed. The results show that the hyperbolic model can accurately predict the change pattern of soil thermal conductivity during the freezing process. Among these four models， the proposed hyperbolic model has the smallest root mean square error and relative error. The model parameters are closely related to the fine particle content and decrease as the initial volume moisture content increases. Considering the new model can accurately simulate the variation of thermal conductivity with subzero temperature， it can provide a basis for coupled heat and mass transfer in cold regions.

In the stilling pool of the spillway and flushing tunnel， there are often problems such as unstable fluctuation range of hydraulic jump and even overtopping the side wall. In order to obtain a good energy dissipation and erosion prevention effect of the stilling pool， the fluid movement during the flood discharge process of the spillway and flushing tunnel was studied through a combination of numerical simulation and physical model testing， which was beneficial for gaining hydraulic dynamics of the flow field and the downstream riverbed erosion conditions. The hydraulic characteristics of water flow under different stilling pool body shape optimization schemes were analyzed， and those schemes were verified by physical experiments. The results show that the flow pattern is more stable under adding a rectangular tailgate at the stilling pool， the water surface fluctuation is reduced. At the same time， the maximum decrease of inlet and outlet velocity in the stilling pool is 7.66 m/s. The pressure distribution is uniform， no negative pressure is generated， and the energy dissipation rate reaches 80.60%. After the addition of the rectangular tailgate， the riverbed scour pit range of the design and verification conditions are reduced by 12.20 m and 13.30 m compared with the original scheme， and it’s maximum scour pit depth are reduced by 0.48 m and 1.00 m compared with the original scheme， respectively. The decrease of the riverbed scour pit range and the maximum scour pit depth shows that the addition of rectangular tailgate has obvious protective effect on the downstream. The research shows that the stilling pool body shape optimization scheme can effectively improve its energy dissipation. The flow field distribution of the optimized stilling pool body shape is uniform， which have great protection on the downstream river bed. The research results can provide reference for diversion and flood discharge and sand flushing projects.

The aseismic capability of the water intake tower-traffic bridge， a crucial component of the reservoir's infrastructure， is essential for ensuring the safe operation of the reservoir after an earthquake. Taking the water intake tower-traffic bridge at Shenzhen Beikeng Reservoir as an example， its seismic response was analyzed with finite element method， and its aseismic safety was evaluated. The maximum transverse displacement of the traffic bridge is 3.15 cm， and the minimum distance between adjacent decks is 2.97 cm during the design earthquake. There is no occurrence of beam dropping or collision between adjacent bridge panels. The traffic bridge experiences significant amplification of seismic accelerations in the earthquake. The maximum amplification for the bridge deck's transverse seismic acceleration is 4.01， and for the longitudinal direction， it is 3.36. During the design earthquake， the dynamic shear stress levels in the pier columns of the bridge are not high， indicating that column shear failure is unlikely. However， there are relatively high tensile stress values on the outer vertical side of the bottom of the pier columns. Additionally， the lower beams of the bridge piers exhibit high tensile stress on both the top and bottom surfaces. To ensure the seismic safety of the bridge pier structure， anti-seismic reinforcements are necessary at pier columns and beams.

The position of the tongue plate in the suction chamber of a double-suction centrifugal pump affects the velocity and pressure distribution at the impeller inlet， which has a significant impact on the cavitation performance of the pump. Taking a single stage double-suction centrifugal pump as the research object， and numerical simulation was used to analyze the effects of different tongue plate positions （45°， 90°， 135°， and -45°） on the internal flow characteristics and cavitation performance. The results show that when the tongue plate is positioned at 90° and 135°， the low-pressure region near the outlet of the suction chamber enlarges significantly， and the circumferential velocity range opposing the impeller rotation direction gradually increases. This leads to increased hydraulic losses at the impeller inlet and higher critical cavitation numbers， resulting in decreased cavitation performance. When the tongue plate is positioned at -45°， the low-pressure region near the outlet reduces significantly， and there is no circumferential velocity opposing the impeller rotation direction. This leads to decreased hydraulic losses at the impeller inlet. Under low and rated flow conditions， the change in critical cavitation number is not significant， but the void fraction and cavitation region within the impeller are reduced at all stages of cavitation. Under high flow conditions， the critical cavitation number decreases more significantly. Overall， the tongue plate positioned at -45° exhibits better cavitation performance. This study provides reference for the design of suction chambers.

In Argentina's Mendoza River Basin （33°S）， glaciers provide an essential supply of freshwater. They act as sensitive climate change indicators and are crucial for comprehending and evaluating changes in local and global climate. Based on Landsat remote sensing imagery from 1990 to 2020， this study aims to understand the distribution and changing patterns of glaciers in the Mendoza Basin and their influence on regional water supplies and ecosystems. It makes use of ratio threshold algorithms and manual interpretation to get glacier boundary data from seven different eras， using the Argentine National Glacier Inventory and the RGI glacier catalog. Furthermore， by integrating climate data from TerraClimate， the study examined the influence of regional climate change on glacier fluctuations and demonstrated the trajectory of climate change in this area during the study period. The findings show that： ① The Mendoza Basin's glacier area was 134.09±11.86 km2 in 2020. The glacier area decreased considerably （p<0.01） between 1990 and 2020， totaling 86.87±21.30 km2 （39.31±10.14%）. The greatest rate of retreat was recorded between 2010 and 2020. ② The majority of glaciers are more than 10 km2， while the least common are less than 0.1 km2. The biggest glaciers are melting the quickest. The majority of the glaciers are found on the southern slopes， with the northwest slopes having the fewest and the southeast and northeast slopes seeing the quickest rate of retreat. Their range of slopes is mostly 5° to 40°， with 50° to 55° being the quickest of retreat. With the greatest retreat rates below 4000 meters， the bulk are located at elevations between 4 200 and 5 400 meters. ③ The Mendoza region has seen a considerable increase in temperature since the late 1950s （p<0.001）， with an average decadal rise in maximum and minimum temperatures of 0.53 ℃ and 0.29 ℃， respectively. In the Mendoza Basin， glacier retreat is mostly caused by long-term increases in temperature； short-term factors include variations in precipitation. This research offers a guide for mitigating the effects of glacier fluctuations on the Mendoza Basin's water resource availability and geological calamities.

Based on the hydrometeorological data in half a month during the flood and dry seasons at four buoy stations in the inner Lingdingyang estuary， the tidal dynamics， runoff dynamics and other powers on average velocity during a tidal cycle had been discussed by introducing the algorithm of main tidal flux section and the binary linear regression method. It showed that average water depth velocity in half a month during the flood and dry seasons in the inner Lingdingyang waters is between 25~45 cm/s， with little difference between flood and dry seasons except at the West beach waters， where the average water depth velocity in the flood season is significantly greater than that in the dry season.. The coefficient a， which represented the contribution on velocities by tidal dynamic， was always positive， indicating that it is the main driving force for the reciprocating movement of the Lingdingyang estuary. The coefficient b representing runoff dynamic was negative at rising the tide stage and positive at the ebb tide stage during the flood season， showed that freshwater discharged into the Lingdingyang estuary by the east four mouths possessed a large initial momentum which strengthened the power of ebb current； while was negative irrespective of rising or falling current during dry season， showing that runoff dynamic was weak and diluted flux mainly moved with tidal current. The coefficient c by other dynamics during the flood and dry seasons was mainly related to density baroclinic gradient force caused by monsoon and salt water intrusion， and there was a good linear negative correlation with the coefficient b by flux of freshwater， more obvious during flood season. Applying incipient velocity of suspended sediment in the Lingdingyang estuary， combined with the fitting formula of average velocity at a tidal cycle obtained by the binary linear regression method， the concept of critical runoff was put forward， and the reason of the phenomenon of "beach scour channel siltation" existed in the Lingdingyang estuary was explained. The Lingdingyang estuary was in the state of sedimentation as a whole during the dry season with more significant during the rising tidal ohase.

Guangdong Province is rich in rural small hydropower station resources， with nearly 10 000 small hydropower stations in Guangdong Province， ranking first in the country in terms of quantity. Small hydropower station has played an important role in solving rural electricity consumption and promoting rural economic development.However， with the advancement of technology， the adjustment of national industrial policies， and the advancement of ecological civilization construction， small hydropower in Guangdong Province is facing needs such as green transformation and strengthened management. Therefore it is necessary to analyze the problems and countermeasures of small hydropower in green total factor intelligent management. This research shows that small hydropower in Guangdong Province has problems such as hidden dangers in production safety， insufficient protection of ecological flow， low degree of automation in operation and management， and difficulty in supervision. Problems mentioned above can be solved by establishing a safety production standard mechanism， implementing ecological flow， promoting the green transformation of small hydropower， and carrying out all-factor Intelligent management and other measures.

Based on the "air-land-water" integrated model system and multi-level collaborative architecture of the basin， this paper proposes a technological system for a non-point source pollution forecasting and warning platform for the Pengxi River basin， and a non-point source pollution forecasting and warning platform for the Pengxi River basin has been established. By automatically collectting and processsing meteorological data， and invoking the meteorological model， land model， hydrodynamic model， and water quality model driven by the control center， the platform can make hourly simulated forecasts of land surface runoff and the flow of pollutants such as TN， TP and NH3-N for the next 3 to 15 days， and warn about the risk of pollutant fluxes， providing technical support for the intelligent basin management and comprehensive control of non-point source pollution.

Under the background of systematic and full-field promotion of sponge city construction， the allocation of Low Impact Development （LID） facilities holds significant implications for urban stormwater management. In this study， we established a stormwater model for the Yixing City area in Jiangsu Province， utilizing the Storm Water Management Model （SWMM）. A comprehensive objective function was formulated， taking into account the reduction rates of runoff volume， Suspended Solids （SS） load， Life Cycle Cost （LCC）， and the area occupied by LID facilities. Through the assignment of weights to objective parameters in different scenarios， the multi-objective optimization problem was transformed into a single objective optimization problem， where each weight represented the priority of the corresponding objective parameter. The Genetic Algorithm （GA） was then applied to derive the optimal LID layout under diverse scenarios， to analyze and compare the impact of different priorities and recurrence periods of target parameters on optimization results. The results indicate that： ① Under the same weight conditions， LCC exhibits a more pronounced impact on GA optimization calculations compared to LID area. ②The spatial allocative optimization of LID facilities in small subcatchments located upstream is particularly susceptible to the rainfall return period. The research findings offer valuable insights for the spatial allocative optimization of LID facility and urban flood control in sponge city construction.

Restricted by the inlet and outlet position of the fishway， engineering geology， hub layout and other factors， the fishway project needs to arrange the turning section of the pool chamber at different angles to adapt to complex and ever-changing engineering environments. This article adopts numerical simulation method to study the flow field distribution law of the turning section of a fish lane with vertical slits on the same side at different turning angles α （90°≤α≤180°）， and systematic optimization measures are proposed for different turning angles. The results show that when the turning angle α is greater than 90 °， the mainstream impacts the outer wall， and there is a large-scale recirculation zone in the middle of the pool. With the increase of the turning angle α， the impact of the mainstream is intensified， and the scale of the recirculation zone is further expanded. In view of the above flow field problems， the measures of adding rectifier guide plate are adopted for optimization. It is proposed that when the turning angle α is between 90° and 140°， the α ₀/α value of the guide plate position with better rectification increases from 1/4.0 to 1/2.8. When α is between 140° and 180°， the α ₀/α value is basically stable between 1/2.8 and 1/3.0. That is to say， with the gradual increase of the turning angle α， the better α ₀/α value increases first and then tends to be stable， It can provide reference for the optimization design of similar arrangement fishway in turning section structure.

The adverse impacts of seawater intrusion on coastal subsurface freshwater resources have significantly constrained the socio-economic development of coastal areas. The construction of subsurface dams in coastal unconfined aquifers is a common measure to prevent seawater intrusion and to safeguard coastal groundwater resources. In practical engineering， coastal aquifers are often heterogeneous， especially with a wide distribution of layered heterogeneous. In order to investigate the influence of the layered heterogeneous of the coastal aquifer （a highly permeable interlayer exists in the middle of the aquifer） on the removal process of residual saltwater upstream of subsurface dams， a two-dimensional numerical model of seawater intrusion at the field scale was constructed based on the SEAWAT-2000 program. The model was used to analyze the pattern of change in residual saltwater transport for a variety of scenarios， including different subsurface dam heights， subsurface dam locations， and high permeability interlayer thicknesses. The simulation results show that the reasonable arrangement of subsurface dams can significantly reduce the range and extent of seawater intrusion， and the existence of intermediate high permeability interlayers will increase the distance of seawater intrusion and reduce the height of the saltwater wedge relative to homogeneous aquifer. The height of the subsurface dam is greater than the height of the saltwater wedge at the location of the dam in order to effectively prevent saltwater intrusion and remove residual saltwater behind the dam. The time for removal of residual saltwater will increase with the height of subsurface dam； meanwhile， the closer the placement of the subsurface dam to the maritime boundary， the longer it will take to remove the residual saltwater behind the dam. The presence of a highly permeable intercalation greatly alters the desalination time of the residual saltwater， and the residual saltwater removal time will be extended in an aquifer containing an intermediate coarse intercalation compared to a homogeneous aquifer. It was also found that as the thickness of the intermediate coarse interlayer increases， the removal time of residual saltwater will first increase and then decrease； however， the effect is small relative to the height and location of the subsurface dam.

Water body extraction from high-resolution remote sensing images often results in incomplete and discontinuous extraction results due to factors such as complex types of ground objects and narrow rivers.To address these challenges comprehensively， combined with the spectral and texture characteristics of the water body itself， this paper proposed an innovative method for water body extraction and optimization in high-resolution remote sensing images that combines global features and local interconnection. The proposed method integrates the intrinsic spectral and textural features of water bodies， adopting a strategy of initial extraction followed by optimization and skillfully blending global and local communication features. Firstly， linear tributaries are recognized based on the initial water extraction results using multi-scale Frangi filtering and the OTSU segmentation algorithm and river replenishment is applied to these linear features， resulting in preliminary optimization results. Then， a locally interconnected disconnection continuation algorithm is introduced to connect disjointed segments in the preliminary optimization results ingeniously. The final stage involves the extraction of water body segments using K-means clustering， and topology inspection and spectral inspection are performed with the accurate optimization results to achieve verification and screening of blocky water bodies. Then， rigorous checks are conducted to validate and filter block-shaped water bodies， ensuring the precision of the extraction results. Experimental results validate the outstanding performance of this method， particularly in the extraction of small tributaries， resulting in a substantial improvement in optimization accuracy. Introducing the disconnection continuation algorithm enhances the completeness of river extraction and fortifies the overall robustness of water body extraction. Comparative analysis with other methods reveals an overall accuracy improvement of 1.04% and 1.50%， along with an increase in comprehensive value by 5.84% and 8.28%， respectively. It can be used as a means to effectively improve the post-processing of water body optimization and improve the integrity and accuracy of water body extraction.

Tunnel construction and continuous drought both can cause significant decrease in groundwater level in karst regions， which can bring serious ecological and environmental issues. Thus， a quantitative evaluation of the influence of these two factors on karst groundwater system is important for engineers and local residents to take effective countermeasures. In this study， the coupled discrete conduit-continuum model method was used to establish a three-dimensional numerical model considering dynamic construction progress in the Jiulongling tunnel construction region. The model was calibrated by using hydrogeological information of study area and available observations. The effects of tunnel construction and drought on the groundwater system during August-October 2022 were evaluated by using the method of controlling single influencing factor. The results showed that the range of groundwater levels affected by drought during the equilibrium period of the study area accounts for 55.43% （about 649.72 km²）， which is 35.1 times of the impact of tunnel construction， which indicates that the drought was the main reason for the lowering of the groundwater level in the study area. With the continuous drought， the overall decline of groundwater level along the tunnel was mainly affected by drought， but the significant decline of water level at some sporadic locations above （such as 14 ~ 15 km， 18 ~ 19 km from the tunnel entrance） the tunnel axis could be attributed to the water inrush into a tunnel segment under construction. According to water balance analysis， during the equilibrium period of August-October 2022， the reduction in recharge due to drought was about 8.245×10⁶ m³， which was significantly more than the groundwater loss caused by tunnel inrush， and the continuous drought had the greatest impact on the groundwater in the study area. This work demonstrates the impacts of underground engineering activities and drought on spatial and temporal evolutions of karst groundwater， and can provide guidance and reference for the hydrogeological assessment of the impact of underground engineering projects.

Soil water content is one of the important factors affecting the growth of crops， and plays an important role in crop yield estimation and drought monitoring. In soil water content calculation， multiple spectral variables are generally extracted for inversion， but the spectral information contained between the variables may have redundancy and overlap. In order to extract effective feature variables and make them independent of each other， the thesis selects the feature variable screening method and verifies the applicability in soil water content inversion. Based on the UAV multispectral images， 12 types of vegetation indices such as Normalized Difference Vegetation Index （NDVI） are calculated， combined with UAV thermal infrared（TIR）data to calculate the Land Surface Temperature （LST） and the corresponding Temperature Vegetation Dryness Index （TVDI）， as well as four backscattering coefficients obtained from miniSAR data processing. XGBoost feature variables and the Best Subset Selection （BSS） algorithm were used to screen the optimal variable combinations， and then Partial Least Squares Regression （PLSR） and Random Forest Regression （RFR） algorithm was used to invert， the soil water content at the tasseling stage of winter wheat in the experimental area. The research results show that： ① The inversion results of 0~20 cm depth are better than those of 0~10 cm depth； ②Comparing the four soil moisture inversion models of XGBoost-PLSR， XGBoost-RFR， BSS-PLSR and BSS-RFR， the inversion accuracy of the RFR model at different depths is the highest； ③The inversion accuracy of the XGBoost-PLSR model is better than that of XGBoost-RFR at a soil depth of 0~10 cm， but the inversion accuracy is the opposite at a depth of 0~20 cm， where the inversion accuracy of the BSS-RFR model is higher than that of BSS-PLSR. The research results can provide theoretical and technical support for UAV multispectral remote sensing inversion of soil water content， and provide test basis for satellite remote sensing large-scale soil moisture monitoring.

In recent years， the frequent occurrence of urban waterlogging disasters caused by extreme rainfall due to climate change has posed a threat to urban water safety and sustainable development in China. Accurately grasping the public opinion and emotions in the disaster-stricken areas is of great importance for improving the situational awareness capabilities of emergency management departments in dealing with waterlogging disasters. In today's era of intelligent networks， the increasing importance of social media as a platform for people to voice their problems and suggestions has made it a major carrier of public sentiment and societal opinion， providing a new avenue for obtaining information about natural disasters. A key technical challenge that needs to be urgently addressed is how to quickly extract urban flood disaster information from social media， and how to perform thematic categorization and sentiment analysis of natural disaster information to accurately grasp the thematic categories of regional disaster situations and public opinion trends. Taking Sina Weibo as an example， this article elaborates on the methods of collecting and pre-processing flood disaster data， and constructs a thematic classification and sentiment analysis model of urban flood disaster information based on FastText to accurately capture the thematic categories and public opinion orientations of disaster-stricken areas. The research results， using the “7.20” heavy rain and flood disaster in Zhengzhou in 2021 as an example show that the methods proposed in this article achieve intelligent extraction and analysis of urban flood disaster data on social media. The theme classification model achieves an F1 score of over 0.80 for the classification prediction of the eight predefined categories， and the sentiment analysis model is generally able to accurately predict data labelled as “negative” in sentiment， which indicates that the FastText-based urban flood disaster information theme classification and sentiment analysis model constructed in this article can meet the needs of urban emergency management departments to dynamically grasp the development of flood disasters and public emotions. It holds significant guiding importance for flood prevention and disaster mitigation planning， calming public emotions， and pinpointing rescue efforts in real time.

Accurate assessment of runoff abundance and depletion encounter characteristics in the basin under runoff non-consistency conditions in multiple temporal dimensions （year-round， flood season and non-flood season） and multiple spatial dimensions （different hydrological stations） is of great significance to the regional flood and drought resistance， and the integrated development and utilization of water resources. We propose a method to analyze the runoff abundance and depletion encounters in a watershed considering the runoff non-consistency. Taking the mainstem of Weihe River as an example， we analyze the runoff evolution of the mainstem of Weihe River at Linjiacun， Xianyang and Huaxian stations from 1960 to 2020 through the sliding average method and Mann-Kendall method， and construct the Copula joint distribution function among different stations from the watershed scale in different time periods， and the abundance and depletion encounter characteristics of the Weihe River mainstem under runoff non-consistency conditions are analyzed. The results show that： ① The runoff of the main stream of the Weihe River has obvious characteristics of wet and dry evolution， and there was a sudden change around 1978， and the runoff sequence after the sudden change showed a significant downward trend. ② The synchronism of the run-off in the main stream of the Weihe River decreases with the increase of the distance between the stations. The synchronism of the run-off in the main stream of the Weihe River is the highest at Linjia Village - Xianyang Station， and the synchronism of the run-off in the main stream of the Weihe River is the lowest at Linjia Village - Huaxian Station； Among the different wet and dry encounter combinations， the most likely occurrence of two sites is the flat-flat combination， and the least likely occurrence is the wet and dry combination. ③ After the runoff variation， the synchronization of wet and dry encounters between different stations has changed significantly. The synchronization of wet and dry encounters between Linjiacun Station and Xianyang Station has decreased significantly， and the synchronization of wet and dry encounters between Xianyang Station and Huaxian Station has increased significantly. Before the variation， the synchronization between the stations in the non-flood season is the strongest， and the synchronization between the stations in the whole year is the weakest. After the variation， the synchronization between the stations in the non-flood season is the weakest， and the synchronization between the stations in the flood season is the strongest. The research results can provide a reference for the characterization of runoff abundance and depletion encounters in the main stream of the Weihe River.

Water pricing is a crucial lever for promoting the rational allocation of water resources， which is related to the healthy development of the economy and society. Scientifically and reasonably determining water prices is the core of achieving healthy and orderly development. Currently， the formulation of water prices in China is difficult to unify due to the complex approval mechanism， different formation times of costs， and the lack of a scientific cost-benefit relationship between multiple water sources and multiple users. To promote quality-based supply of water and utilization of recycled water， to achieve high-quality and low-cost water， to play the role of water price mechanisms in the complex configuration of multiple water sources， it is imperative to establish a scientific and reasonable water price equilibrium system for multiple water sources and multiple users. This article starts from the perspective of water price marketization， fully considers the supply and demand conditions of the multi-water source market， the role mechanism of supply and demand subjects and their geographical factors in the multi-water source pricing process. Taking Yiwu City as an example， this article constructs a Stackelberg game model between local governments， water supply enterprises， and water users respectively in the leading position， and compares and analyzes the equilibrium prices and benefits of the three subjects under different conditions. The results show that under the condition that water users dominate， the price of multi-water sources is the lowest， and under the condition that water supply enterprises dominate， the overall benefits are the highest， and the price system obtained is as follows： the price of water from water storage—resident users is 5.63 CNY/m³； the price of water from water storage—non-resident users is 6.20 CNY /m³； the price of water from water storage—special users is 6.21 CNY /m³； the price of river water—non-resident users is 3.34 CNY /m³； the price of recycled water—resident users is 2.95 CNY /m³， and the price of recycled water—non-resident users is 3.06 CNY/m³. This pricing system can achieve the balance of reasonable profits for water supply enterprises， reasonable payments for water users， and rational allocation of water resources， providing theoretical support for the marketization of water pricing and providing reference for further research in this field.

Water governance is an important issue of the modernization of the national governance system and governance capacity， and is also an critical guarantee for high-quality development and the Chinese path to modernization. The detailed identification and systematic evaluation of the Chinese path to modernization of water governance is the key work to promote the modernization and sustainable development of China.A comprehensive evaluation system for the Chinese path to modernization of water governance is constructed from the demensions of population， economy， coordination， and ecology under the guideline of the characteristics of the Chinese path to modernization， and the spatial-temporal characteristics of the development of the Chinese path to modernization of water governance are explored by spatial analysis methods based on the provincial-level panel data from 2008 to 2021， and the influencing factors of the Chinese path to modernization of water governance are analyzed by using the grey correlation model.The results show that the development of the Chinese path to modernization of water governance is overall on the rise； The regional heterogeneity of the Chinese path to modernization of water governance is significant， showing a gradient pattern of "high in the east， followed by the middle and low in the west"， and the regional gap has an expanding trend. Indicators such as urbanization rate， urban water access rate， urban sewage treatment rate， per capita comprehensive water consumption， total population， proportion of ecological water， and water consumption per 10 000 yuan of industrial added value have the highest correlation with the Chinese path to modernization of water governance. This study suggests that differentiated， targeted and forward-looking development strategies and policies should be formulated for the Chinese path to modernization of water governance for various regions. The western region should further increase the ecological water， and the central region can improve the modern development level of water governance by optimizing the per capita comprehensive water consumption.The research enriches the theoretical system of the Chinese path to modernization， and provides a scientific basis for the development of Chinese water governance.

In order to deeply analyze the drought and flood disaster response patterns of Tuojiang River Basin under the background of climate anomalies， this paper reconstructs the time series of drought and flood disaster of Tuojiang River Basin in the Qing Dynasty， and analyzed its related data with mathematical statistics， mutation test， power spectrum cycle analysis， ADF and Granger causality test， etc.， to explore the occurrence patterns of drought and flood disasters in the Tuojiang River Basin in the Qing Dynasty and its climate driving force factors.The results show that， during the Qing Dynasty， 208 drought and flood disaster occurred in the Tuojiang River Basin， with an average of one drought and flood disasters occurring every 1.29 years.There were more flood disasters than drought disasters， with a total of 21 persistent flood and drought disasters and an overall high level of severity of disasters.Drought and flood disasters were interspersed frequently， and there were also drought and flood disasters coexisting during the same year.Drought and flood disasters were concentrated in a chain-like distribution from 1800 to 1910.The number of disasters peaked in the middle of the Qing Dynasty， and mega-disasters were concentrated in the middle and late Qing Dynasty. The year 1863 was an important mutation point for drought and flood disasters， after which the number of disasters increased significantly. Drought and flood disasters in the Qing Dynasty were significantly correlated with the average annual sunspot number， and continuous disaster events were more frequent around sunspot extreme years.The change cycle of drought and flood disasters is about 2.5 a， which is strongly consistent with the ENSO cycle.The number of drought and flood disasters in the Tuo River Basin was significantly higher during ENSO event years.With a lag period of 1a， sunspot activity and ENSO events are the main climatic triggers of drought and flood disasters changes.The research results not only fill the research gap of drought and flood disasters mechanism in the Tuojiang River Basin under climate change， but also enrich the knowledge of spatial and temporal distribution pattern and regularity of drought and flood disasters in the Yangtze River Basin. It provides a useful reference for strengthening the scientific use of water resources and disaster prevention and mitigation， and also provides an important reference for the flood and drought prevention and ecological civilization construction in the Tuojiang River Basin.

The construction and operation of reservoirs have led to significant alterations in downstream flow. In order to fully account for the reservoir regulation effects in monthly runoff simulations， the Dongjiang basin was selected as a representative watershed. Using Particle Swarm Optimization-Long Short-Term Memory （PSO-LSTM） algorithm， the outflows of three multi-functional reservoirs—Fengshubao， Xinfengjiang， and Baipenzhu—in the Dongjiang basin were simulated and a comparison was made with the traditional reservoir model， Level Pool Scheme （LPS）. Additionally， Three-Parameter Monthly Hydrological Model Based on the Proportionality Hypothesis（TMPH） was employed for simulating reservoir inflow and interval low-flow， forming the combined models PSO-LSTM-TMPH and LPS-TMPH. These models were applied for one-month lead time runoff simulations at key sites in the Dongjiang basin， including Longchuan， Heyuan， Lingxia， and Boluo.The results indicate that： ① PSO-LSTM outperformed LPS in simulating the three major reservoirs， particularly in the outflow simulation of Xinfengjiang Reservoir. During the validation period， the Nash-Sutcliffe Efficiency （NSE） and Root Mean Square Error （RMSE） were 0.59 and 55.59 m³/s， respectively. Compared to LPS， this represented an increase of 0.22 and a decrease of 17.01 m³/s， demonstrating the model's ability to effectively capture the complex regulations of reservoir outflows over multiple years. ② For the PSO-LSTM-TMPH model， the NSE for runoff simulation at Longchuan， Heyuan， Lingxia， and Boluo stations was 0.87， 0.86， 0.91， and 0.93， respectively. Compared to LPS-TMPH， the NSE increased by 0.09， 0.21， 0.07， and 0.03， indicating improved accuracy. ③ During the testing period， the PSO-LSTM-TMPH reservoir outflow simulation remained effective， with smaller differences compared to the training and validation periods， suggestting strong model generalization capabilities.The hybrid model， PSO-LSTM-TMPH， established in this study， leverages the strengths of both deep learning and physical models. It is suitable for runoff simulation under human activity disturbances and provides technical support for optimizing water resource utilization and implementing drought scheduling.

Slope has an important effect on the runoff production process. Slope correction of runoff curve number in the SCS-CN runoff production model is important to improve the model prediction accuracy， In order to conduct an investigation of the effect of average watershed slope in the runoff production process， in this paper， based on Huang's slope modification formula， the first 40 out of 70 rainfall runoff measurements in the study area from 1955 to 1981 were used as the validation data， and a ₁ and a ₂ parameters in Huang's slope modification formula were re-determined， so as to propose the slope modification formula of the CN value for the study area under three different antecedent moisture conditions， and then the SCS-WJG method， which is of good applicability to the region， was established and compared to the SCS-CN look-up table method， and the SCS-Huang method， which is a direct transfer of the Huang's slope modification formula. The conclusion is as follows： the λ-value of the initial rainfall loss rate determined using the ergodic method is 0.09， so the standard value of 0.2 is not applicable to the study area. After comparing the size of the CN values obtained by the three methods， it is found that the CN value obtained by the SCS-Huang method is the largest， followed by the SCS-CN look-up table method， and the smallest is obtained by the SCS-WJG method， so the CN value obtained by the SCS-WJG method is more suitable for the study area as shown in the simulation results. Comparison of the SCS-CN lookup table method and the SCS-Huang method reveals that the NSE of the SCS-Huang method is lower and the RMSE is higher； therefore， it is necessary to propose a slope correction formula for the CN value applicable to the study area and establish the SCS-WJG method. When λ = 0.09， the NSE of the SCS-CN lookup table method， and the SCS-Huang method are -2.85 and -3.25， respectively， while the NSE of the SCS-WJG method is increased to 0.86， and the RMSE of the SCS-WJG method is reduced by 77%， and 78%， respectively， compared with the first two methods. The simulation accuracy of the SCS-WJG method is significantly better than that of the remaining two methods， indicating that the SCS-WJG method has good regional applicability and can provide a reference for the simulation of runoff production in small watersheds.

Evapotranspiration （ET） is a crucial link in water circulation. It plays an important role in the global water cycle and surface energy balance， and has significant impacts on climate， ecosystems， and water resources management. Therefore， the quality of evapotranspiration data is crucial for the precise management of global water resources. This study conducted accuracy validation and spatiotemporal comparison of three ET products in the Northern Hemisphere， selecting the ET products that is more suitable for the Northern Hemisphere， providing suggestions for strengthening the combination of remote sensing and ground observation research. Using the monthly average measured data from FluxNet2015 flux sites to verify three ET products， it was found that PML_ V2 product has the highest accuracy in the Northern Hemisphere， followed by GLDAS， and finally MOD16A2， with correlation coefficients R of 0.66， 0.57， and 0.56， respectively； The root mean square error （RMSE） is 2.46， 5.68， and 12.42 mm/month， respectively； The average biases are 14.36%， 16.86%， and 35.02%， respectively. The GLDAS ET product has the ability to monitor daily scale ET， and the consistency between the daily average estimated value and the measured value at the flux tower site is high. The correlation coefficient R is 0.74， and the RMSE and Bias are 1.62mm/day and 27.90%， respectively. Overall， on the time scale， all three ET products can simulate the seasonal changes in the Northern Hemisphere， with higher summer evapotranspiration and lower winter evapotranspiration. The three ET products in summer all have overestimation phenomena on different land cover types， and the simulation results in other seasons are better than the ground observation values. Among them， MOD16A2 performs the worst， and the overestimation phenomenon is the most obvious. In addition， during the period from 2001 to 2020， except for arid areas， the spatial distribution of the three ET products was relatively consistent in most regions， with a correlation coefficient R greater than 0.6. This study provides scientific recommendations for selecting suitable ET data sources for conducting evapotranspiration studies in the Northern Hemisphere by evaluating the uncertainty and product quality of different ET products.

It is very easy to encounter the phenomenon of water and mud gushing during construction and excavation of tunnel through karst area. How to choose appropriate anti-seepage measures to reduce the seepage flow of tunnel has always been a hot issue. In this paper， a three-dimensional finite element model of complex strata in karst area is established based on a water diversion project. Three anti-seepage measures， namely back-filling concrete on the roof of the tunnel， grouting ring around the tunnel and concrete cutoff wall， are mainly considered. The change law of pore water pressure and seepage flow of the tunnel during tunnel excavation is studied， and the influence of permeability coefficient of the cutoff wall and grouting ring on seepage characteristics is analyzed. The results show that the concrete cutoff wall has a great influence on the distribution of pore water pressure in the tunnel， the water level between the cutoff walls decreases obviously， and the grouting ring around the tunnel has the greatest influence on the seepage flow of the tunnel， and the quality of the grouting ring should be ensured during construction. The pore water pressure increases with the increase of the horizontal distance from the tunnel center， and increases first and then decreases with the increase of the vertical distance from the tunnel center. With the increase of the permeability coefficient of the grouting ring or the cutoff wall， the pore pressure growth rate in the area of the grouting ring or the wall decreases gradually， and the seepage flow of the tunnel increases continuously.

The lack of some hydrological data or short hydrological sequences makes it difficult to predict the power generation capacity of small hydropower stations， and this paper summarises three prediction methods： ARIMA model， LSTM model， and large and small hydropower station correlation method， in order to effectively solve this problem. Taking Ni'ao Gia Ga power station in Gannan area as an example， with the actual power generation data of the power station in 2022 as the test standard， and based on the power generation and water inflow data from 2015 to 2021， ARIMA model， LSTM model and large and small hydropower station correlation method are successively used to predict the power generation capacity of small hydropower stations in this area. The results show that the correlation method of large and small hydropower stations using the flow of large hydropower stations as the relevant factor can effectively predict the amount of water coming from small hydropower stations， and then get the prediction results of power generation with higher accuracy， which is obviously better than the ARIMA model and the LSTM model， and it can be popularised and applied in similar areas.

After long-term operation of a generator， the stator winding will gradually experience aging or electrical corrosion， and scientific experimental analysis methods are needed to diagnose the health status of equipment. By analyzing the leakage current data of stator winding DC withstand voltage tests of multiple large tubular generators， this paper proposed an insulation performance evaluation method and measures to prevent winding breakdown； according to the electrical corrosion and high operating temperature of stator winding of wall mounted structure， we studied a series of innovative designs and processes for stator renovation， and conducted finite element simulation calculation of stator temperature field. The temperature rise test data shows that the operating temperature of the generator after stator modification is effectively reduced， and there is significant reduction in temperature deviation at each measuring point. The research results are close to the simulation calculation values， proving that the new process adopted for stator transformation is effective and feasible.

With the advancement of the national “dual carbon” strategic goals and the planning of new energy systems， the proportion of new energy connected to the power grid is rapidly increasing. Therefore， it is urgent to accelerate the planning and construction of energy storage， and promote the transition of the power system from “source-network-load” to “source-network-load-storage” multi entity coordinated evolution. In this context， from the perspective of energy storage as a regulatory resource， this article establishes a comprehensive evaluation index system for the power grid that fits the connotation of the new power system. The selection of indicators follows the SMART principle to ensure the application value and operability of the indicators； and uses the Analytic Hierarchy Process to calculate the weights of each indicator layer by layer. Taking the four provinces in Central China of State Grid as examples for analysis， the evaluation results of each province can be clearly quantified， among which Hunan has the highest comprehensive score. The research results of this article have certain guiding significance for the implementation and comprehensive evaluation of energy storage planning in various regional power grids.

With the post epidemic economic recovery and development， Liaoning Province experienced a severe electricity shortage in 2021. This article is based on a systematic analysis of the current situation of hydropower development and the degree of hydropower resource development and utilization in Liaoning Province， pointing out the problems， construction opportunities， advantages， and disadvantages faced by current hydropower development； Based on the relevant planning achievements of hydropower development in Liaoning Province for many years， this paper analyzes the planning situation of conventional hydropower stations and pumped storage power stations that can be constructed in the future in Liaoning Province； By analyzing specific cases of using upstream and downstream reservoirs to construct pumped storage power stations， suggestions for ensuring the development of hydropower in Liaoning Province are proposed， providing reference for the hydropower construction in Liaoning Province in the new era.

Cofferdam seepage and slope stability are related to the stability of the cofferdam itself and whether the dry construction conditions can be formed in time， which greatly affects the construction period of the main building. Based on the cofferdam construction and foundation pit drainage of TB hydropower station in Lancang River， ABQUAS and SLIDE software were used to study the seepage stability of cofferdam body and slope stability under the condition of sudden drop of foundation pit water level in each construction stage of the cofferdam cut-off wall. The results show that： with the gradual completion of the construction of the cut-off wall， the stabilization time of the seepage line of weir body is gradually reduced， and the seepage line stabilization time is longer under the condition of greater water level difference between the inside and outside of the foundation pit； under the condition that the construction of the phase 1 trench of the cut-off wall is completed and the phase 2 trench is in the process of slurry retaining wall， if the water level plunge in pit can be controlled to not exceed 0.9 m per process， the cofferdam slope can remain stable， and at this time the foundation pit can be allowed to advance drainage. based on the result， the strategy and program of advance drainage of tb hydropower station pit were studied. the results of the study can provide reference for similar projects.

Based on the survey data of hydropower immigrants in Yantan， Guangxi， the combination empowerment method and Topsis model are used to quantify the sustainable livelihoods composed of three abilities， and variance analysis is used to explore the impact of follow-up supports and their specific measures on the sustainable livelihoods for the overall and three types of immigrant households in order to evaluate the effectiveness. The results show that the overall sustainable livelihood level of immigrant households is lower than the medium level， and the sustainable livelihood level of non-poor households， general poverty alleviation households and low-income poverty alleviation households decreases successively. Comprehensive assistance has significantly improved the sustainable livelihoods of overall immigrant households. The involvement of specific measures has different effects on the sustainable livelihoods for different immigrant households，among which education and training have significant effects on the improvement of the sustainable livelihoods of three types of immigrant households. The number of measures involved has a significant impact on the sustainable livelihoods of non-poor households and low-income poverty-stricken households， but has no meaningful impact on ordinary poverty-stricken households. This paper expands the research methods in the field of of evaluating the effectiveness of follow-up support for immigrants， which can provide a basis for accurately and efficiently promoting immigrants support.

Considering that the statics/dynamics analysis about the large emersed radial gate are always over-simplified by previous investigations， in this paper， the static and dynamic characteristics of single gate and gate-dam system are analyzed and compared in detail using the ANSYS finite element software. A finite element model（FEM） of gate-dam system considering seal friction， supporting hinge system and prestressed anchor cable is established based on the instantaneous opening condition of spillway radial gate of a hydropower station. The research results show that： in terms of statics， the two sides of the water seal have little influence on the stress distribution of the steel structure components in the gate， with a maximum difference of 14.08%； Also， more reasonable stress distribution of fixed hinge is obtained from gate-dam system comparing with that of single gate； Besides， the anchor block affects the overall displacement of the gate prominently， and the degree of effect can be sorted as： the overall displacement of the single gate < the integrated displacement of the gate dam without the prestressed anchor cable < the overall displacement of the gate dam with prestressed anchor cable. In terms of the dynamics analysis， frequency of the gate structure is reduced by the water seal when fluid-structure interaction effect is taken into account； And the prestressed anchor cable has little influence on the dynamic characteristics of gate-dam system.