Studying the propagation of meteorological drought to hydrological drought is essential for meteorological information-based drought management and hydrological drought warning systems. Taking the Ganjiang River source basin as an example, this paper uses the basin's monthly meteorological and hydrological data for the past 60 years to study the propagation pattern of meteorological drought to hydrological drought, and explores the differences in drought propagation among sub-basins. The results show that the propagation of meteorological drought to hydrological drought has various ways, with a one-to-one correspondence; The drought events increase hazards after propagation from meteorology to hydrology; The Logistic model can better reflect the response relationship of hydrological drought characteristics to precipitation shortage conditions; The large reservoirs have a significant effect on the drought resistance of the basin.

In order to deal with the serious problem of siltation in the main channel of the Yellow River Diversion Irrigation Area in Zuncun Village, Shanxi Province, a field water and sediment test was carried out on the main channel. The distribution law of suspended sediment in the channel, the relationship between channel flow and sediment deposition, and the sediment carrying capacity of the channel flow were explored by using the vertical suspension index and the planning solution method, so that it could express the sediment carrying capacity of the flow within a certain range. The critical suspended flow corresponding to the channel particle size was put forward. It was beneficial to prevent siltation by adjusting the flow according to the working conditions and particle size. The sediment carrying capacity formula was optimized. The conclusions are as follows: When the diversion flow is 4.46-24.52 m³/s, the sediment content in the channel is between 0.9-4.0 kg/m³, and the sediment content is positively correlated with the flow velocity. The channel flow can be properly adjusted to more than 39.6 m³/s to effectively suspend the sediment with large particle size. The correlation between the optimized sediment carrying capacity formula and the measured value of the main channel sediment reaches 0.828, which indicates that this formula can reflect the current sediment concentration to a high degree, and provide support for the design and analysis of the balance of channel erosion and deposition in the later stage.

The health of the water cycle is a key factor in high-quality regional development. The prediction of water cycle health state is of great significance to the coordinated development of regional water resources system, economic and social system and ecological environment system. Taking Zhengzhou City as a typical research area, this study constructed a DPSIR model for urban water cycle health evaluation, and analyzed the evolution process of water cycle health status in Zhengzhou from 2010 to 2020 by using entropy weight fuzzy comprehensive evaluation method. The system dynamics model and entropy weight fuzzy comprehensive evaluation method were used to predict the health status of water cycle in Zhengzhou from 2021 to 2030 under five types of comprehensive coordination type, economic development type and water resources optimization type. The results show that the health status of water cycle in Zhengzhou has been developing well in the past decade, and the indicators of per capita GDP, urbanization rate and intelligent water resources management have reached the "healthy" state. Under the five prediction scenarios, the urban water cycle reaches the state of "subhealth" or above, and under the comprehensive coordination scenario that takes into account economic development, ecological protection and water resources optimization, the water cycle health status of Zhengzhou reaches the state of " health", and this scheme is the optimal scheme. The results can provide theoretical basis and technical support for ecological protection and high quality development in Zhengzhou City.

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.

In order to explore the causes of urban waterlogging, taking Guangzhou as an example, a drainage model was established based on SWMM. A waterlogging cause analysis method based on real-time monitoring data was proposed. Combining with the real-time monitoring data, the water-collecting capacity of water-logging points, the flow capacity of pipeline and the runoff generated by rainstorm were calculated. At the same time, the corresponding waterlogging measures were given according to different waterlogging causes. The results show that 75% of waterlogging cases involved insufficient surface drainage capacity, 57.7% of waterlogging cases involved watercourse top support, and 44.2% of waterlogging cases involved excessive rainfall intensity and insufficient pipe drainage capacity.

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.

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.

To improve the added value utilization rate of reservoir sediment in the field of construction materials, the reservoir sediment was used as auxiliary cementitious material to prepare pervious concrete. The results show that with the increase of reservoir sediment content, the compressive strength of the specimens will decrease, and the permeability will increase. With the extension of mechanical activation time, the compressive strength of the specimen increases and the permeability decreases. When the water cement ratio is 0.3, the mechanical activation time is 45 min, the 28 d compressive strength of the prepared pervious concrete can reach 21.44 MPa, and the permeation coefficient is 0.56 mm/s. The results of this study can provide reference for the resource utilization of reservoir sediment in the field of building materials.

Aiming at the problem that the background harmonic voltage fluctuation and the abnormal harmonic measurement samples significantly affect the accuracy of harmonic impedance estimation, a method for calculating utility harmonic impedance based on generalized jackknife least square estimation and data screening is proposed. According to the principle that the assumption of the fluctuation method and least squares regression are the same, the measurement period when the background harmonic voltage fluctuation is stable is selected for the regression calculation, which can restrain the influence of background harmonic voltage fluctuation on impedance estimation. According to the jackknife principle, the harmonic measurement data is resampled, and the generalized least square method is combined to effectively suppress the adverse effects of abnormal measurement data on the regression. The accuracy and practicability of the proposed method are verified by simulation and actual measured data test.

In order to explore the impact of moisture change on the pore structure of reshaped loess, different times of humidification-dehumidification cycle tests were carried out for remodeled loess with different dry densities, and the pore structure inside the soil under different cycles was tested by nuclear magnetic resonance technology. The results show that the NMR T₂ pattern of reshaped loess presents a bimodal structure, that is, the sample contains two pore structures; The dry and wet cycles have an impact on the change of the pore structure of the loess, and the pore structure shows different laws under different times of dry and wet cycles. Finally, based on the quantitative parameters extracted from the T₂ pattern, the permeability of reshaped loess under different cycles were calculated by SDR permeability model, and the permeability mechanism of loess was explained from the microscopic aspect.