Based on the temperature load on the wall slab of a large aqueduct when the temperature suddenly drops, the temperature self-confinement stress of the upper surface of the concrete slab was tested and analyzed. The temperature difference between upper and lower surfaces of concrete slabs at different cooling rates and the self-constrained principal stress of concrete slab surface temperature at 1 h at a cooling rate of 10 ℃/h were measured. The accuracy of finite element modeling was verified by comparing the numerical value of concrete transient temperature stress simulated by finite element method with the experimental test data. On this basis, the influence of cooling rate on transient temperature and stress field of aqueduct was analyzed. The impact of different insulation materials on surface temperature and stress field of aqueduct was discussed. The results show that the temperature tensile stress on the aqueduct surface will increase at a faster rate with the increase of the ambient temperature decreasing rate. Compared with the external surface temperature stress of the aqueduct without insulation measures, the tensile stress of the external surface temperature of the U-shaped aqueduct was reduced by 83%, 80% and 68%, respectively, when the polyurethane, polystyrene board and vitrified microbeads with 2mm thickness were adopted. Considering the cost and construction technology, vitrified microbead insulation materials are more suitable as thermal insulation materials on the outer surface of aqueducts.

With the completion of a large number of major water conservancy projects with the characteristics of "high water head, large flow, and complex geological conditions", the environmental problems caused by flood discharge atomization have become increasingly prominent, and it is urgent to carry out research on mitigation technology of flood discharge atomization. The types of flip bucket have a direct impact on flood discharge atomization. Based on the methods of physical model test and numerical simulation calculation, the influence of flip bucket types on flood discharge atomization is studied. The results show that: under the same test conditions, the distribution of the nappe wind velocity of the continuous bucket is symmetrical along the two sides of the downstream axis, showing a unimodal distribution; and the distribution of the nappe wind velocity of the contraction bucket and the expansion bucket is approximately symmetrical bimodal distribution. The distribution of flood discharge rainfall is closely related to the type of the flip bucket. Compared with the continuous bucket, the number of the splashed water droplets of contraction bucket and expansion bucket is greatly increased. In the actual project, the purpose of reducing the influence of flood discharge atomization can be achieved by reasonably optimizing the types of flip bucket.

An accurate hydrological model with strong adaptability is crucial for predicting floods and preventing disasters. The antecedent soil moisture and rain intensity factors are considered to improve the SCS-CN runoff generation model. Then the new SCS-CN hydrological model is developed by adding the watershed concentration module. From the perspectives of different climate zones and magnitude floods, the new model is applied in four basins to flow simulation, which include semiarid basins of Hancun and Macun, and humid basins of Shenglihe and Gongcheng. The results demonstrate that new SCS-CN hydrological model has good applicability in both semi-arid and humid basins, with better performance in semi-arid basins. Generally, the model shows better accuracy in simulating floods of different magnitudes, especially for small and medium floods.

The regulation and storage capacity of a river channel plays an important role in the safety of drainage in polder areas. In order to study the factors related to the actual effective regulation and storage capacity of a river channel in polder areas, this paper adopts the unsteady flow model and the water balance method to calculate the regulation and storage capacity of a single river channel. The calculation results of the two methods show that the main influencing factors of the regulation and storage capacity of a river channel are the water depth corresponding to the starting regulation level, the roughness of the river channel, the length of the river channel and the cross-section morphology, etc. For the backbone drainage channel with large discharge, the actual effective regulation and storage capacity is the storage capacity from above the water surface line corresponding to the designed discharge to the maximum water level. The research results have certain reference value for the planning and design of drainage in polder areas.

In order to understand the water quality of Wuliangsu Lake, an inversion method of total suspended matter concentration based on M-GA-BP was proposed. Using Sentinel-2 remote sensing satellite images as the data source and considering the spatial and temporal characteristics existing in the study area, the monthly data was considered as a feature for the inversion of TSM concentration. The GA-BP model was built by optimizing the weights and thresholds of the BP neural network using genetic algorithm (GA), and comparing with the traditional BP neural network model. The results show that the introduction of the monthly feature model effectively reduces the model complexity and improves the model inversion accuracy, among which the M-GA-BP model has the highest inversion accuracy with the coefficients of determination of 0.916 and 0.903 for the training and test sets, respectively, and the root mean square errors of 0.049 μg/L and 0.057 μg/L for the training and test sets, respectively. The study can provide a new idea for the inversion of TSM concentration in the Wuliangsu Lake.

Photovoltaic power generation is affected by the chaotic characteristics of meteorology, and its stochastic, volatile and intermittent characteristics affect the operation of power systems seriously. Aiming at the problem of large dimension of original PV power generation data and the vulnerability of power generation to weather conditions, a data processing method based on Principal Component Analysis (PCA) and BRICH clustering was proposed to reduce the dimensionality of model input variables and facilitate statistical modeling. Secondly, a Copula-Monte Carlo-based probabilistic PV power probabilistic prediction model was constructed to calculate the probabilistic interval prediction of PV power output given the future point prediction values. The model was evaluated based on interval coverage and average width of prediction interval. Finally, the summer data of the actual photovoltaic power station were taken as an example for verification analysis. The results show that the Copula-Monte Carlo method can intuitively show the fluctuation range and expected value of photovoltaic power generation, and is superior to other power prediction models.

On the non-uniform sand river bed, the armor layer at the bottom of the bridge pier local scour pit will affect the maximum local scour depth of the bridge pier. Through a flume model experiment, the sediment gradation, relative coarseness, and non-uniformity of the armor layer at the bottom of the local scour pit on the bridge pier were studied. The results indicate that the median particle size of the sediment in the armor layer at the bottom of the local scour pit on the bridge pier increases with the increase of the local scour depth on the bridge pier, and its relative coarsening degree increases with the increase of the Froude number, while the degree of non-uniformity decreases with the increase of the Froude number. A formula for calculating sediment particle grading in the armor layer at the bottom of the local scour pit on the bridge pier has been proposed. The applicability and reliability of the proposed formula is verifies by the measured data.

The current regional water supply and power generation structure is not able to achieve sustainable development in the long term. It is worth exploring whether the production, trade and the corresponding water footprint of the power sector in the Beijing-Tianjin-Hebei (BTH) region can meet the long-term development needs of the region after the dual-carbon goals is proposed. Therefore, this study constructed a dynamic multiregional computable general equilibrium model to simulate the changes in the production and trade of the power sector and its water footprint in the BTH region caused by the carbon reduction policy. Four carbon reduction scenarios were designed in the model to explore the impacts of policies such as carbon tax, investment and renewable energy subsidies. The results show that the carbon tax policy has the most significant water saving effect on power generation; The carbon reduction policy significantly increases the inter-regional flow of virtual water in the power trade; The complete water footprint of the power sector under various scenarios does not change much (less than 15%), in which the water footprint of the power sector in Beijing has the highest sensitivity to the carbon reduction policy. Therefore, the focus of water conservation in the power sector under the dual-carbon target should be on the trade chain, optimizing the trade structure and reducing interregional virtual water flows.

Exerting huge economic and social benefits, the construction and operation of water conservancy projects have an impact on the ecological environment of upstream and downstream reaches. However, it is also an effective way to regulate and improve the ecological environment by rationally optimizing the water storage and release process of the reservoir and carrying out targeted ecological management of the reservoir. From the perspective of ecological flow constraints, through data investigation and analysis, the appropriate flow ranges of the Yangtze River main stream conducive to the natural reproduction of the four major Chinese carps, Chinese sturgeon and the control of estuary salt tide intrusion were determined. Then, the optimal scheduling model of the Three Gorges Reservoir was established considering the downstream ecological flow constraints. Multi-objective reservoir ecological dispatching model is emphasized. The results show that the ecological flow of the lower reaches of the Three Gorges Reservoir was basically guaranteed during the wet season from May to September, but the ecological water shortage was prone to occur in different degrees in other seasons, especially in the dry years. For the optimal scheduling, the power generation and the monthly maximum ecological water shortage rate showed a positive relationship, indicating that the two scheduling objectives could not reach the optimum simultaneously. The power generation of the optimal scheduling in a typical dry year was between 80.2 billion and 83.5 billion kW·h, and the monthly maximum ecological water shortage rate was between 24% and 48%. The optimal scheme obtained by multi-objective dispatching can basically coordinate the ecological and power generation needs. On the basis of the downstream ecological flow needs, the power generation benefits increases by 4.07% compared to the design scheme.

In view of the influence of the analysis method of geosynthetics axial tensile test results on the authenticity of mechanical properties, the mechanical properties of PVC geomembrane and HDPE geomembrane materials were studied respectively, and the relationship curves of the two materials under different analysis methods were obtained. Then the error of material tensile index under the two analysis methods was compared. The results indicate that the experimental curves obtained by the true stress-strain analysis method considering thickness changes can more accurately reflect the tensile deformation process of materials. When the materials are different, the modulus errors of the materials under the two analysis methods are also completely different. However, the variation law of the true stress-strain curve is more consistent compared to standard methods for processing, which can more accurately evaluate the material's ability to adapt to load deformation.