[Objective] Cone penetration testing(CPT) and its pore-pressure extension, piezocone penetration testing(CPTU), have formed a relatively mature observation-interpretation framework in terrestrial geotechnical engineering, with cone tip resistance(q_c), sleeve friction(f_s), and pore pressure(u₂) as the core measured parameters. When terrestrial CPTU is extended to shallow subsurface exploration on the Moon and Mars, factors such as low gravity, near-vacuum or rarefied atmospheric conditions, intense thermal cycling, and ice-bearing, saline, cemented, and unsaturated regolith can systematically alter stress paths, boundary conditions, measurement-chain stability, and the interpretability of measurement responses during penetration. To meet the demands of lunar water resource exploration and Martian shallow subsurface engineering investigation, the response mechanisms, applicability boundaries, and technical development directions of CPTU-like techniques under lunar and Martian environmental constraints are systematically reviewed. [Methods]Taking the terrestrial CPTU interpretation framework as the reference baseline, the analysis follows the main line of “environmental constraints-measurement chain-response indicators-interpretation boundaries. ” It examines three representative mission scenarios: ice-bearing regolith in the lunar polar regions, near-surface engineering conditions in non-polar lunar regions, and sampling/drilling scenarios in candidate Martian plains. On this basis, the impacts of low gravity, vacuum or rarefied atmosphere, ice-/salt-bearing and unsaturated media, and existing mission observations on the formation mechanisms and interpretation framework of q_c, f_s, and u₂ are synthesized. Additionally, possible directions for system improvement, multi-sensor joint constraints, ground-equivalent calibration, and probabilistic interpretation under small-sample conditions are discussed. [Results] The impact of low gravity is not merely limited to reducing the in situ stress level. It also alters the reaction force supply, attitude stability, and penetration boundary conditions, making q_c and f_s more prone to exhibiting abrupt or threshold-type responses. This undermines the direct applicability of terrestrial empirical charts and continuous parameter inversion relationships. Near-vacuum or rarefied atmospheric conditions and thermal cycling significantly affect the stability of the pore-pressure measurement chain, making u₂ more suitable as a conditional auxiliary observation parameter in extraterrestrial scenarios that can be used only after state diagnosis. Under the near-vacuum conditions on the Moon, when its physical attribution remains unclear, u₂ should not be directly used for the inversion of soil mechanical parameters. The presence of ice, salts, cementation, and layered structures further enhances the non-uniqueness of penetration responses. Given the current evidence, layer identification, interface identification, and event-type response analysis are generally more appropriate as priority interpretation approaches under complex media conditions. Existing mission data can provide external constraints on bearing capacity, shallow structure, and penetration boundary conditions, but they cannot directly replace the standard CPTU calibration system. [Conclusion] For lunar and Martian applications, the key to CPTU-like investigation does not lie in simply replicating the terrestrial three-channel configuration, but in reconstructing a mission-oriented framework that integrates the measurement chain, penetration boundary conditions, multi-source constraints, and interpretation/evaluation. Future efforts should focus on ground-equivalent calibration under low-gravity conditions, validation of pore-pressure measurement stability under vacuum and thermal cycling, investigation of penetration mechanisms and applicability boundaries in ice-/salt-bearing regolith, and development of ground-equivalent databases and tiered uncertainty-based interpretation schemes, so as to support the advancement of CPTU-like techniques for lunar water resource exploration and extraterrestrial shallow subsurface engineering investigations.

[Objective] The physical and mechanical properties of lunar regolith are clarified to support deep-space exploration and the construction of scientific research stations, and to further reveal the relationship between particle parameters of lunar regolith and its occurrence environment to guide the preparation of lunar regolith simulants. [Methods]The environmental information of lunar regolith sampling sites since 1969 was systematically reviewed. The published indicators of lunar regolith, including mineral composition, particle gradation, bulk density, and fractal dimension were summarized. The raw materials and preparation method of typical lunar regolith simulants were analyzed, and research progress on the characteristics of lunar regolith under simulated lunar environments was examined. On this basis, research recommendations and development prospects for preparation method of lunar regolith simulants were proposed from the perspective of soil mechanics. [Results] The result showed that the Si O₂ content in lunar regolith accounted for approximately 45%, and the dry bulk density ranged from 0. 89 to 1. 6 g·cm^-3. The particle gradation was dominated by fine particles, with significant differences among different sampling regions. Among morphological parameters, the fractal dimension ranged from 2. 28 to 2. 55, and the specific surface area ranged from 0. 40 to 0. 56 m²·g^-1. The single-material grinding and sieving method for lunar regolith simulants was suitable for largescale tests. A similarity of more than 85% was achieved by the multi-mineral precise compounding method, and a compressive strength of 3. 2 ~ 21. 52 MPa was obtained via the functional modification preparation method. Experimental studies on lunar regolith simulants focused on three major themes: mechanical property tests, biological planting tests, and physical effect tests. [Conclusion] The dominant minerals of lunar regolith are plagioclase, pyroxene, olivine, and ilmenite, exhibiting “low-alkali and high-iron” characteristics, with significant differences in mineral composition between mare and highland samples. The current preparation of lunar regolith simulants can adopt corresponding method according to different objective, and the effective similarity evaluation of lunar regolith simulants can be conducted from three dimensions: mineral composition, physical properties, and mechanical properties. The findings can provide references for the preparation of lunar regolith simulants and the study of physical and mechanical properties of lunar regolith.

[Objective] To address the issue of insufficient physical mechanisms in the distributed hydrological model SPHY for snowmelt runoff simulation in cold regions(specifically the neglect of solar radiation and the use of static degree-day factors), the snowmelt module is optimized and enhanced to improve the accuracy of snowmelt runoff simulation in cold regions. [Methods]Three improvements were made:(1) constructing a radiation-coupled potential snowmelt energy term;(2) proposing a seasonal dynamic degree-day factor based on the snow depth-solar radiation relationship; and(3) quantifying the importance of different factors during the snowmelt process based on random forest. Taking the Niyang River Basin in the southeastern Qinghai-Xizang Plateau as the study area, the simulation performance of the improved model was verified based on meteorological, hydrological, and remote sensing data from 2010 to 2015. The contribution rates of different meteorological factors to snowmelt runoff were quantified through trend analysis, correlation analysis, and random forest models. [Results] The model simulation result showed that during the calibration and validation periods, the average Nash-Sutcliffe efficiency(NSE) of the improved model during the snowmelt period increased by 8%, the root mean square error(RMSE) reduced by 17%, and the overall Percent bias(PBIAS) was optimized from-14. 77% to-0. 05%. Driving factor analysis showed that air temperature was the dominant factor for snowmelt runoff(contribution rate of 41. 79%), and the wind speed contribution rate reached 25. 58%. The total contribution rate of energy factors(air temperature and radiation) reached 61. 08%. [Conclusion] The improved scheme coupling solar radiation with the seasonal dynamic degree-day factor effectively enhances the runoff simulation capability of the SPHY model in cold regions. The findings provide references for runoff simulation in other alpine river basins, and offer scientific support for runoff forecasting and water resource management under climate change.

[Objective] In the context of global climate warming, both temperature and precipitation in the source region of the Yangtze River have shown increasing trends, leading to enhanced glacier melt and snowmelt and intensified river evolution. Clarifying the spatiotemporal evolution patterns of plateau river channels under climate change is of great significance for the enhanced understanding of response and evolutionary characteristics of plateau rivers and for the conservation of ecological environment. [Methods]Based on remote sensing imagery of the Dangqu River Basin in the source region of the Yangtze River and temperature and precipitation data from three nearby meteorological stations from 1990 to 2023, the spatiotemporal evolution patterns of river channels in the Dangqu River Basin were quantitatively investigated. This was achieved by the MNDWI method, channel centerline method, Mann-Kendall trend analysis, and maximum value composite(MVC) method. Additionally, interannual variations in curvature, width, and lateral migration rates of river channels from 1990 to 2023 were analyzed. [Results] The result showed that within the 152 km river section of the Dangqu River Basin, straight channels accounted for approximately one-third, while meandering channels accounted for two-thirds. Over the past 34 years, the average curvature of river channels in the Dangqu River Basin was 1. 14, exhibiting only a 2% decrease during this period. The river width of the Dangqu River continued to increase, with an average growth of 9. 4% and an annual increase of 0. 4 m/a. The normalized lateral migration rate of the river channels [= total lateral migration distance/m（year of migration × river width）]decreased by 48%, with an average annual reduction of 0. 014 over the 34-year period. [Conclusion] The river width and normalized lateral migration rate are significantly influenced by temperature and precipitation. Increased glacier melt and snowmelt induced by rising temperatures, combined with higher precipitation, jointly lead to higher river discharge and elevated water levels, thereby promoting the widening of river channels in the Dangqu River Basin. In addition, these changes in hydrological conditions are favorable for vegetation growth, which strengthens bank stabilization and suppresses lateral channel migration, resulting in a decreasing trend in the normalized lateral migration rate.

[Objective] To evaluate the response effectiveness of the flash flood monitoring and early warning system under extreme weather conditions, the Wanquan River Basin in Hainan Province is taken as the study area, and the rainstorm flood process triggered by the combined influence of the residual circulation of Typhoon “Trami”(2024, No. 20) and a cold air mass is used as a case study. Based on the China National Flash Flood Hydrological Model(CNFF) and the Hainan Flash Flood Monitoring and Early Warning Platform, a four-stage early warning evaluation framework covering “forecasting-monitoring-warning issuance-disaster verification” is established. [Methods]Rainfall monitoring data, hydrological model simulation result, and field survey information from 96 key villages were integrated. Using the administrative village as the evaluation unit, the hit rate of warnings at the alert level(“ prepare for evacuation”) and above was analyzed. [Results] The result showed that: the platform issued a total of 115 warnings at the level of “prepare for evacuation(alert)” and above, covering 70 administrative villages under prevention and control. Among them, 50 villages actually experienced disasters, corresponding to a warning hit rate of 71. 43%. [Conclusion] The monitoring and early warning platform has relatively strong capability in trend identification in key risk areas, but deficiencies exist in village-level response adaptability and the rationality of threshold settings. Improvement directions are proposed, including dynamic adjustment of early warning thresholds, optimization of flood process simulation, and multi-source data fusion, so as to enhance the adaptability and early warning effectiveness of the system under extreme meteorological conditions. The findings can provide a reference for the optimization of flash flood monitoring and early warning systems and the improvement of risk governance capacity in tropical monsoon regions.

[Objective] Digital twin technology has demonstrated significant application and practical value in large river basins and specific point-based projects. However, numerous challenges remain in implementing the “four-pre”(forecasting, early warning, rehearsal, and contingency plan) system for water conservancy facilities at the district and county levels. It is of great significance to address key challenges such as complex geospatial data, fragmented mathematical models, and slow cross-level scheduling in the digital twin “four-pre” system at the district and county levels. [Methods]Huairou District, Beijing, was selected as the study area. A differentiated monitoring and perception system was established across the entire district, built upon a three-tier architecture comprising an infrastructure layer, a digital twin platform layer, and a smart application layer. The system was designed by integrating the characteristics of district-level water management, the current status of informatization, and the geospatial characteristics of mountain-plain transition zones. A lightweight algorithm for large-scale multi-source data fusion was proposed. In view of the collaborative needs of multiple departments and levels within the district water authority, an application framework was established for cross-level joint scheduling and consultation. To evaluate the practical effectiveness of the research framework, model loading tests, analytic hierarchy process(AHP), and scenario analysis were used for quantitative evaluation of framework effectiveness. [Results] The result showed that the lightweight algorithm significantly optimized model size, reducing the rendering load by approximately 83%. Through the use of encapsulated hydrological model libraries and collaborative applications, the comprehensive “four-pre” capabilities of flood disaster prevention and mitigation in Huairou District were theoretically improved by about 70%. [Conclusion] The findings indicate that the platform can improve precise perception, intelligent simulation accuracy, and collaborative scheduling effectiveness of water conservancy facilities in Huairou District. This approach is applicable for administrative units at the district and county levels with complex geographical environments, numerous water conservancy facilities and multi-level cross-departmental management collaboration, thereby providing a reference for similar cases nationwide.

[Objective] The evolution of extreme precipitation and the result ing population exposure risks are critical issues in global climate change studies. However, traditional assessments focusing solely on frequency or intensity cannot fully capture the complexity of these evolutionary processes. The evolving pattern of extreme precipitation across China from a dual-dimensional perspective of frequency and intensity is analyzed, and quantitatively identify changes in population exposure and the underlying drivers, thereby providing a scientific reference for formulating precise disaster prevention strategies and climate change adaptation plans. [Methods]The Multi-Source Weighted-Ensemble Precipitation(MSWEP) dataset and the China Historical Population Spatial Distribution Kilometer-Grid Dataset were employed. The K-means clustering method was adopted to establish an integrated classification system for extreme precipitation based on frequency and intensity. By comparing the periods of 1981—1999 and 2000—2020, different shifts in extreme precipitation type were identified, and the evolutionary pattern of population exposure as well as the contributions of distinct factors(e. g. climate, population) were quantitatively assessed. [Results] The results revealed that approximately 23% of the area in China experienced a shift extreme precipitation types, dominated by changes in either frequency or intensity alone(e. g., intensified intensity with unchanged frequency), whereas synchronous alterations in these two aspects only accounted for about 1%. Furthermore, changes in population exposure to extreme precipitation across the two periods displayed marked spatial heterogeneity, with an increase of exposure occurring in around 70% of the whole country, especially in southern and eastern coastal regions. At the national scale, population change dominated the change in exposure with national average contribution rate of 67% followed by climate change(~ 30%). However, in northeastern and northwestern China, climatic factor exerted a dominant influence on the changes in population exposure. [Conclusion] The findings reveal the complex characteristics of divergent evolution of extreme precipitation in China across both frequency and intensity. Traditional assessments relying on a single dimension might underestimate or misjudge disaster risks. Future management of extreme weather risks requires formulation of differentiated strategies for disaster mitigation, prevention and adaptation based on the spatial heterogeneity of evolution in extreme precipitation type.

[Objective] Clarifying the spatiotemporal evolution characteristics of carbon storage and habitat quality in the context of ecological land fragmentation, as well as their interaction effects, is crucial for regional ecosystem protection and management.[Methods]Taking the Hutuo River Basin as the research object, the spatiotemporal evolution characteristics of habitat quality and carbon storage were quantitatively analyzed and their correlation with the comprehensive landscape fragmentation index of ecological land was explored by using the land use dynamic rate, land use transfer matrix, comprehensive landscape fragmentation index, In VEST model, FRAGSTATS 4. 2 software, and geographically and temporally weighted regression( GTWR) model. [Results] The result showed that:(1) from 2000 to 2020, the area of ecological land in the river basin showed a decreasing trend, while the mean value of the comprehensive landscape fragmentation index for ecological land increased with fluctuations.(2) The habitat quality in the Hutuo River Basin exhibited a declining trend, dropping from 0. 42 in 2000 to 0. 38 in 2020. Regions with relatively high habitat quality were mainly concentrated in the central part, northwestern edge, and southeastern part of the study area.(3) Carbon storage in the Hutuo River Basin showed a gradual decreasing trend, falling from 320. 23×10⁶ t in 2000 to 313. 81×10⁶ t in 2020.(4) The fragmentation of ecological land had a negative effect on both habitat quality and carbon storage. The interaction between habitat quality and carbon storage exhibited significant regional differences, with an overall positive correlation but variations in the intensity and pattern of the interaction. [Conclusion] The findings can provide theoretical guidance for ecological land protection, habitat quality improvement, and ecosystem restoration in similar river basins.

[Objective] Regulating reservoir releases profoundly alters river hydrology and hydrodynamics. While intra-day peak regulation by daily-regulating hydropower stations can re-regulate the flow processes generated by upstream regulating reservoir releases, the impact of this re-regulation on fish habitats downstream of the dam remains unclear. [Methods]The Luding Nanqiao spawning reach was selected as the research object, and a two-dimensional planar hydrodynamic model was constructed. Based on the hourly inflow and outflow hydrographs on typical days during the spawning season(March and April) of Schizothorax prenanti from 2018 to 2021, the hydrodynamic characteristics of the reach under various typical flow conditions and intra-day hourly flow variations were simulated. Furthermore, the physical habitat simulation method was used to analyze the spatial distribution patterns of suitable spawning habitats and assess the impact of intra-day peak regulation on the intra-day variations of the weighted usable area(WUA). [Results] Flow variations significantly altered the distribution of flow velocity and water depth in Luding Nanqiao spawning ground reach. The WUA exhibited a unimodal response to increasing discharge, peaking at 33 800 m² at 80 m³/ s. Regarding overall habitat suitability, compared to inflow scenarios, the average values of WUA on most typical days under outflow scenarios showed a slight decrease, with a reduction rate of 1. 96% ~ 10. 45%, while the intra-day minimum WUA increased significantly, with an increase rate of 13. 82% ~ 40. 89%. In terms of habitat stability, both the coefficient of variation for the habitat and the average intra-day WUA variation decreased on most typical days under outflow scenarios, with increases observed only on certain days in 2020. Concerning the risk of short-term habitat degradation, the maximum hourly WUA reduction effectively decreased by 903 ~ 11 747 m² on most days. However, the maximum hourly WUA reduction increased during the typical days of March and April 2020 under outflow scenarios. [Conclusion] The impact of intraday peak regulation at Luding hydropower station on spawning habitat suitability varies with the operational regime. For most typical days, daily regulation has a limited influence on the overall habitat suitability of the Nanqiao spawning reach. However, it improves habitat stability to some extent and reduces the risk of short-term habitat degradation. Nevertheless, under certain operating scenarios, hydropower regulation may increase habitat fluctuations and exacerbate the risk of short-term habitat degradation within the spawning reach.

[Objective] To clarify the current status of fish diversity in Yuqiao Reservoir, compare the application effectiveness of morphological identification and environmental DNA(eDNA) technology in fish resource surveys, and provide data support for protection of the reservoir's water ecological environment. [Methods] From 2022 to 2023, fish were collected using three-layer gillnets and ground cages at five sampling sites, followed by morphological identification. Dominant species were analyzed using the Pinkas index of relative importance, and interspecific relationships were analyzed using niche breadth and overlap models. From May to October 2023, eDNA samples were collected synchronously at each sampling site. PCR amplification and highthroughput sequencing were performed based on 12 S r DNA gene primers, species annotation was completed, and community characteristics were analyzed using α-diversity indices. [Results] A total of 24 fish species were captured through morphological identification, belonging to 5 orders, 10 families, and 23 genera. Cypriniformes accounted for 66. 67%. Six dominant species, including Cyprinus carpio and Rhinogobius giurinus, accounted for 72. 34% of the total catch biomass. The niche breadth of major fish species ranged from 0. 07 to 1. 12, with no broad-niche species observed. Significant overlap was observed in 25. 72% of the 276 species pairs, and the degree of overlap was highest among Cyprinidae species within Cypriniformes. A total of 25 fish species were annotated using eDNA technology, belonging to 5 orders, 11 families, and 18 genera. The average relative abundances of Cyprinus carpio and Aristichthys nobilis reached 38. 53% and 21. 96%, respectively. The Chao1 index(41) and Shannon index(2. 236 4) at station S4 were the highest, while station S18 showed the lowest values(Shannon index 1. 399 4). 12. 8% of species were detected by both method, and comprehensive analysis indicated that approximately 40 fish species may be present in the reservoir. [Conclusion] Fish in Yuqiao Reservoir are dominated by Cypriniformes, and the community structure is significantly influenced by environmental heterogeneity. eDNA technology can effectively complement the limitations of morphological identification, and the combination of both method enables a more comprehensive assessment of fish diversity, providing a scientific basis for ecological protection in the reservoir area.

[Objective] Under the dual pressures of climate change and human activities, water resources carrying capacity has become a critical constraint on regional sustainable development. Water transfer projects, as a vital means to reconstruct the spatial equilibrium of water resources, require carrying capacity assessment that is crucial for project benefits and ecological safety. [Methods] To address the uneven spatiotemporal distribution and scarcity of water resources in Sri Lanka, a focus was placed on the local “South-North Water Transfer” project. The TOPSIS model based on entropy weight-CRITIC combined weighting was employed, and the potential fluctuating impacts of climate change were considered during the assessment. The effects of the water transfer project on the spatiotemporal evolution of water resource patterns across 11 regions in the North Central Province were systematically analyzed. [Results] The result showed that the project significantly optimized water resource allocation. Domestic water demand increased by 37. 9%, and agricultural water demand rose by 26%(partially offset by improved irrigation efficiency). Ecological water demand experienced a modest increase. Spatially, water resources carrying capacity exhibited a distribution pattern characterized by lower values in the central region and higher values in the northeast and southwest, with disparities gradually diminishing. After the implementation of the water transfer project, the evaluation indicators tended toward equilibrium, and agricultural water conservation became the key focus for long-term regulation. [Conclusion] The water transfer project elevates the water resources carrying capacity of most regions in North Central Province from “Weaker”(Grade Ⅱ) to “Moderate”(Grade Ⅲ), but disparities among regions still exist. Future efforts should focus on establishing a priority regulation mechanism for water transfer based on dynamic assessments of water supply and demand. The findings provide a scientific basis for coordinated inter-basin water resource management within the Belt and Road framework.

[Objective] The eastward-moving southwest vortex is an important weather system affecting drought and flood variations in the Yangtze River Delta region of China. However, its specific impact on the Yangtze River Delta region remains incompletely understood. The aim is to investigate the detailed characteristics of regional heavy rainfall in the Yangtze River Delta influenced by eastward-moving southwest vortex. [Methods] Using the “Southwest Vortex Almanac”, CN05. 1 gridded precipitation data, and ERA5 reanalysis data, statistical analysis and case comparisons were conducted on the movement characteristics of southwest vortices and the characteristics of regional heavy rainfall in the Yangtze River Delta region caused by eastward-moving southwest vortices. [Results] The result showed that from 2012 to 2019, a total of 716 southwest vortices were generated. The primary movement path of southwest vortices exiting their source region was eastward. Eastward-moving southwest vortices accounted for approximately 30% of the total cases generated, contributing more than 10% of the total precipitation in the Yangtze River Delta region. [Conclusion] The findings indicate that the eastward movement and development of southwest vortices are favored when the East Asian Trough and the Northwestern Pacific Subtropical High are relatively strong. The impact of eastward-moving southwest vortices on precipitation in the Yangtze River Delta region exhibits significant spatial heterogeneity, with the maximum contribution mainly located in the western part of the region. The areas of heavy precipitation are generally consistent with the movement paths of the southwest vortices, the intensity of the southwesterly warm and moist airflow on the southern side of the vortices, and the locations of strong upper-and lower-level convergence and divergence zones. The specific characteristics of heavy rainfall in the Yangtze River Delta region influenced by eastward-moving southwest vortices, including the large-scale circulation patterns and meso-and micro-scale dynamic configurations, demonstrate their unique impact on heavy rainfall events in this region. These findings provide theoretical references for the operational forecasting of heavy rainfall in the Yangtze River Delta region potentially caused by eastward-moving southwest vortices.

[Objective] The hydrodynamics in channel-type reservoirs exhibit dual characteristics of both rivers and lakes, significantly influencing the longitudinal gradient distribution of water environmental factors. The Minjiang River is the largest river in the coastal region of southeastern China, but the spatiotemporal heterogeneity characteristics of dissolved oxygen(DO) and its influencing factors in mainstream reservoirs remain unclear. [Methods] Based on the hourly monitoring data from 2020 to 2024 in the upstream tributaries and reservoir area of the Shuikou Reservoir in the Minjiang River, an integrated analytical method suitable for channel-type reservoirs was developed by combining STL time series decomposition, modified Mann-Kendall trend testing, Pettitt' s test for change-point detection, and Pearson correlation analysis. This method followed a progressive research framework of data processing, feature characterization, trend assessment, and attribution analysis, thereby systematically elucidating the spatiotemporal evolution patterns of DO in the Shuikou Reservoir. [Results] The result showed that the surfacelayer DO in Shuikou Reservoir exhibited significant longitudinal heterogeneity, with DO concentrations gradually decreasing from the riverine zone(6. 5~7. 3 mg/L), through the transition zone(5. 6~6. 8 mg/L), to the lacustrine zone(5. 2~6. 2 mg/L). Consequently, the risk of hypoxia increased correspondingly, specifically manifested as hypoxia probabilities of 0. 7% ~16. 9% in the riverine zone, 16. 1%~38. 3% in the transition zone, and 27. 6% ~ 46. 1% in the lacustrine zone. The dominant driving mechanisms of DO exhibited significant differences among these zones, and the influence degree of each driving factor dynamically changed over time. Furthermore, the same external events demonstrated significant temporal lag effects across different zones, with response delays ranging from 1 to 4 months. [Conclusion] It is evident that the established integrated analytical method can fully extract deep information from high-frequency monitoring data, elucidating the spatiotemporal heterogeneity characteristics of DO and their driving mechanisms. This provides a basis for further implementing systematic improvement measures, such as external source management in the riverine zone, hydrodynamic-pollution regulation in the transition zone, and internal source control and ecological regulation in the lacustrine zone.

[Objective] Continuous dynamic monitoring of fish resources in the fluctuating backwater zone of the Three Gorges Reservoir is essential for evaluating the effectiveness of conservation measures and for formulating targeted management strategies. Against the backdrop of the 10-year fishing moratorium on the Yangtze River, non-invasive environmental DNA(e DNA) metabarcoding offers an efficient and convenient means of acquiring information on fish assemblages. [Methods] The Guangyangba section in the fluctuating backwater area of the Three Gorges Reservoir, the Upper Yangtze River was selected as the study area. The e DNA metabarcoding was employed to investigate fish diversity within the fluctuating backwater zone of the Three Gorges Reservoir, analyze the fish community composition, and assess fish species within the area, thereby providing data support for conservation of fish diversity in the fluctuating backwater zone. [Results] A total of 63 fish species were detected by e DNA metabarcoding, belonging to 5 orders, 10 families, and 48 genera, with Cypriniformes being the most abundant, accounting for 73 % of all records. The species with relatively high relative sequence abundance included Cyprinus carpio(common carp), Hypophthalmichthys nobilis(bighead carp), Ancherythroculter wangi, and Ctenopharyngodon idella(grass carp). Key environmental factors driving the spatial distribution patterns of fish communities were identified as flow velocity and conductivity. α-diversity among fish in the Guangyangba section of the fluctuating backwater zone in the Upper Yangtze River exhibited minimal variation, with an average Shannon diversity index of 1. 67 and an average Simpson diversity index of 0. 63. β-diversity among different sampling sites was governed primarily by turnover components. Resident species favouring slow-flow habitats and those producing demersal eggs dominated the Guangyangba section. [Conclusion] The fish community structure in the fluctuating backwater zone of the Three Gorges Reservoir is undergoing a redistribution from a riverine to a river-reservoir ecosystem, with habitats preferred by rheophilic, rare, and endemic fish species of the Upper Yangtze River progressively shifting upstream towards the national nature reserve for rare and endemic fish species.

[Objective] In the context of global warming, the continuous rise in lake surface water temperature(LSWT) has become a key factor in exacerbating lake eutrophication. Therefore, accurately predicting its future trends is of great significance for the early warning of lake eutrophication and water environment management. [Methods] Based on MODIS remote sensing images, daily LSWT data for Xingyun Lake from 2002 to 2024 were acquired. The random forest(RF) algorithm was employed to impute missing values. Subsequently, a parallel LSTM-Transformer deep learning model was developed to predict future LSWT trends under different climate scenarios(SSPs). Furthermore, the SHapley Additive exPlanations(SHAP) method was introduced to identify the key driving factors of LSWT and their directions of influence. [Results] The results indicated that:(1) the warming rate of surface water temperature in Xingyun Lake was 0. 27 ℃/10 a from 2002 to 2024, with a particularly pronounced warming trend in autumn.(2) The LSTM-Transformer fusion model exhibited high prediction accuracy, with a coefficient of determination(R²) of 0. 95 and a root mean square error(RMSE) of 0. 89 ℃. Under future climate scenarios(SSP1-2. 6, SSP2-4. 5, and SSP5-8. 5), the LSWT of Xingyun Lake was projected to continue rising at a rate of 0. 11~0. 42 ℃/10 a.(3) Near-surface air temperature and surface downward longwave radiation were identified as the primary driving factors influencing LSWT variations in Xingyun Lake. [Conclusion] The developed deep learning model exhibits good applicability for predicting surface water temperature in plateau lakes. The framework can provide a basis for adaptive water environment management and early warning of ecological risks in plateau lakes under future climate scenarios.

[Objective] The Lanzhou-Xining urban agglomeration, an important cross-provincial urban agglomeration in the upper reaches of the Yellow River Basin, features a fragile underlying environment and rapid urbanization. Therefore, it is necessary to conduct an in-depth analysis of the regional water resources. [Methods] A regional WEP-L model was constructed by comprehensively considering the natural and social aspects of the water cycle. Considering different hydrological years, and based on the concept of generalized water resources and water footprint theory, the current status and consumption of blue and green water resources in the Lanzhou-Xining urban agglomeration were quantified at both administrative region and sub-basin scales. The main influencing factors were then analyzed using the geodetector method. [Results] The results showed that the multi-year average water resource amount in the region was 176. 473 billion m³, of which green water resources accounted for 79. 14%. The proportion of agricultural water footprint to total water footprint in different cities ranged from 58. 45% to 99. 06%. Lanzhou had the largest industrial water footprint, reaching 0. 661 billion m³ in 2009. Lanzhou and Xining had relatively large domestic water footprints, and tourism significantly affected the domestic water footprint of individual sub-basins in Haibei. Altitude and total water supply were the factors with the strongest explanatory power for the regional blue and green water resource amount and the total water footprint, respectively. [Conclusion] The upstream area of the Lanzhou-Xining urban agglomeration is rich in water resources and has relatively low water consumption, making it suitable for establishing water resource protection areas, although tourism development management should be strengthened. Downstream cities should formulate development strategies based on the water consumption characteristics of different sub-basins and improve water resource utilization efficiency according to local conditions. The findings can provide a scientific basis for regional water resource management and allocation.

[Objective] To address the long-standing challenge of parameter identification in hydrological modeling for data-scarce regions within transnational water conservancy projects, a parameter transfer method for a raster-based distributed hydrological model based on land use types is proposed. [Methods] Using land use types as basic units, a “land use-parameter” mapping relationship was constructed to form a structured parameter lookup table. This approach overcame the dependence of traditional parameter regionalization on gauging station density, enabling robust cross-basin parameter transfer under similar underlying surface conditions. The Cambodian section of the Mekong River Basin was selected as a case study. A land use type-parameter lookup table was established through zonal calibration in a reference river basin, which was then transferred to the target river basin for validation. [Results] In the reference river basin(Kompong Cham station), the Nash-Sutcliffe efficiency(NSE) values during the calibration and validation periods were 0. 87 and 0. 86, respectively, with relative errors(RE) in total runoff volume of 5. 71% and 8. 61%. After the parameters were transferred to the target river basin, the NSE reached 0. 87 at the Thnous Loung station on the Das River with an RE of 8. 37%, and the NSE was 0. 89 at the Kralanh station on the Sreng River with an RE of 7. 01%. The accuracy was significantly higher than that of the instantaneous unit hydrograph method(NSE of 0. 76 and 0. 68) and the antecedent precipitation index method(NSE of 0. 32 and 0. 74), demonstrating superior capability in simulating flood peak processes and maintaining water balance. [Conclusion] The proposed method realizes physically based cross-basin parameter transfer using land use as a carrier, fills the gap in hydrological model parameters in data-scarce regions, and provides an effective reference for process simulation in distributed hydrological modeling.

[Objective] Displacement is the most intuitive and reliable reflection of the dam' s operating status and structural behavior under the dual effects of internal and external environments. Establishing a scientific and reasonable dam safety monitoring model is of great significance to ensure its safe operation. [Methods] To address the complex nonlinear, diverse, and time-varying characteristics of concrete dam displacement monitoring data, a two-stage concrete dam displacement prediction model based on Variational Autoencoder(VAE), Improved Northern Goshawk Optimization(INGO) algorithm, Residual Neural Network(ResNet) and Informer is proposed to improve the accuracy of dam behaviour analysis. Firstly, VAE is used to perform latent space modeling and nonlinear feature extraction on temperature monitoring data. Then, the improved Res Net is utilized to deeply characterize the multi-source input impact factors, the Informer model is introduced to capture the long-term dependency information in the data, and the INGO algorithm, enhanced with multiple strategies, adaptively tunes the key hyperparameters of the model to achieve precise modeling of dam displacement. [Results] Taking the displacement monitoring data of a concrete arch dam as an example, the proposed model is compared with the traditional prediction model. And the result demonstrate that the proposed model can accurately predict the dam displacement trend, achieving the best RMSE, MAE and R² values on the displacement data test set of each measuring point. [Conclusion] The proposed model exhibits significant advantages in prediction accuracy, stability and residual suppression ability, providing technical support for the safety monitoring and operation management of concrete dams.

[Objective] The safety of the nuclear power plant cold source is a prerequisite for ensuring the safe and stable operation of generating units. In recent years, frequent incidents of water intake system blockage triggered by large-scale aggregation of marine organisms driven by environmental changes in marine ecosystems have posed serious threats to the safety of nuclear power plant cold source. To systematically enhance the safeguarding capacity of water intake systems while mitigating the impact of intake engineering projects on the marine ecological environment, it is imperative to conduct targeted research on water intake entrainment. [Methods] A three-dimensional hydrodynamic model coupled with a particle migration model was used to systematically investigate the impact of different breakwater designs in water intake open channels of nuclear power plants on the distribution of intake flow fields and the biological entrainment effect of water intake. [Results] The result showed that when the breakwater was designed with a curvature of 90°, the designed water intake velocity was lower than the average tidal flow velocity. The inflow non-uniformity at the intake was approximately 3, and the hydrodynamic conditions demonstrated favorable guiding effects on marine organisms and a lower entrainment rate. Compared to other design scenarios, this configuration could reduce entrainment by approximately 50. 5%. [Conclusion] Different breakwater designs significantly affect the flow field characteristics of open-channel water intake, generating aggregation or guiding effects on marine organisms migrating with the flow near intake structures. This consequently affects biological entrainment during water intake. Appropriate breakwater designs can substantially mitigate the impact of water intake operation on marine organisms while reducing cold source blockage risks. The findings provide method ologies for optimizing the engineering design of water intakes in coastal nuclear power plants and quantitatively assessing water intake entrainment effects, thereby offering a basis for ensuring water intake safety and ecological operation.

[Objective] To investigate the micromechanical properties of basalt fiber asphalt concrete(BFAC), [Methods] a nanoindentation tests with finite element numerical simulations was conducted to thoroughly examine the mechanical responses of the constituent phases of BFAC. A four-phase three-dimensional model comprising the asphalt matrix, aggregate, aggregateasphalt transition interface, and fiber was constructed using Abaqus software. The static implicit algorithm was employed to simulate the indentation process, thereby capturing the evolution patterns of load-displacement response, modulus, hardness, and creep behavior for each phase. [Results] The findings reveal significant variations in the mechanical properties of the BFAC phases. The Young' s moduli of the asphalt matrix, aggregate, fiber, and transition interface were measured at 1. 73 GPa, 76. 69 GPa, 120. 60 GPa, and 34. 39 GPa, respectively. The numerical simulations exhibited a high degree of concordance with the experimental curves, with Young's modulus errors below 5%, thereby validating the efficacy and accuracy of the model in analyzing the micromechanical behavior of BFAC. [Conclusion] The asphalt matrix in BFAC demonstrated the lowest modulus and hardness, with the most pronounced plastic deformation and creep response. In contrast, the aggregate and fiber exhibited high modulus, high hardness, and superior deformation resistance, with creep displacements all below 70 nm. The transition interface' s performance was intermediate between the aggregate and asphalt matrix. Field analysis indicated that the displacement, stress, and strain fields at the indentation point exhibited a distribution characteristic of high values beneath the indenter and low values in the far field. The contours of displacement, stress, and strain expanded elliptically inward, with their magnitudes gradually attenuating with increasing depth. Additionally, the study elucidated the influence mechanism of indenter geometry on the indentation response. Compared to the Berkovich indenter, the spherical indenter, due to its smaller contact area, with a smaller slope in the loading curve. increased the indentation depth by approximately 12% to 28% at maximum load. These findings provide valuable insights for the structural design and performance optimization of hydraulic asphalt concrete materials.