Interbasin water diversion projects alter the spatial optimization of water yield (WY) services through the optimized allocation of water resources. However, only a small number of studies have explored how water resources sourced from water diversion initiatives influence regional carbon storage. Furthermore, there is a notable absence of research focusing on the collaborative spatial optimization of carbon-water ecosystems. We studied carbon-water services (ESs) alignment pre- and post-diversion via quantitative and spatial analysis of WY and carbon sequestration (CS) services in the water-receiving area of the Jiangsu-Shandong section of the South-North Water Diversion Project, China. We aimed to examine the association between diverted water and carbon storage distribution and pinpoint the main driving factors of regional ESs supply and demand relationships. Thus, we propose an optimal management strategy for matching the spatial distribution of carbon-water ESs supply and demand in the context of interbasin water diversion projects. The results showed the following. (1) The supply capacity of WY services in the water-receiving area has been significantly enhanced compared with that before water diversion. After water diversion, the supply per unit area increased from a decrease in 2015 to 2020, growing from 215829.59 m3·km-2 to 355086.39 m3·km-2, with an increase rate of 64.5
Urban levee breaches drastically alter flood behavior and threaten urban safety. This study employs a coupled 1D-2D hydrologic–hydrodynamic model to simulate flood interactions between tributaries and the mainstream under breach conditions, enabling quantitative assessment of spatiotemporal flood dynamics. An exponential decay model with linear regression is introduced to estimate recession parameters, offering a novel means to reveal delayed recession and secondary-peak mechanisms. Results show that breach peak discharge rises with mainstream flood magnitude; higher return periods lead to earlier onset, longer duration, and a “small floods delay, large floods advance” pattern. The exponential decay model effectively represents the recession process: small floods show near-linear decay, whereas larger floods display delayed recession and secondary peaks. Beyond a threshold, secondary-peak intensity increases with tributary inflow disparity. Key hydrodynamic drivers—return-flow processes, channel storage, and backwater effects—jointly cause lagged replenishment, forming secondary peaks after the main flood. These findings highlight the need to include the recession-phase “replenishment period” in flood risk management and emphasize the extended application of the exponential decay model as a novel framework for analyzing breach-flow recession, advancing both theoretical understanding and practical urban flood assessment.
Dam failure can have a significant impact on the lives and health of people downstream, and evaluation models are needed to accurately identify the safety status of dams to prevent such accidents. Aiming at the structural characteristics of embankment, a comprehensive evaluation index system for embankment safety was constructed by considering the influence of monitoring data, site inspection, and review indicators on embankment safety. Indicator weights were calculated separately using subjective and objective weight calculation methods, and the subjective and objective fusion weights of the indicators were calculated by improving the game theory based on the idea of minimizing the overall loss of information. For the uncertainty problem existing in the process of monitoring and evaluation embankment safety, forward and reverse cloud generators are used to realize the mutual qualitative and quantitative conversion, and a calculation method based on the membership degree is used to calculate the error generated by different numbers of cloud droplets to realize a reasonable optimization of the number of cloud droplets. Finally, a comprehensive evaluation model of embankment safety is established. The model was applied to the embankment of the Helong Reservoir in Guangzhou City, Guangdong Province, China, and the results showed that the membership degree of the Helong Reservoir to normal reached 62.9
The accuracy of rainfall data is crucial for precise urban inundation simulations. We examined how various spatial rainfall interpolation methods affect inundation simulation results. We applied interpolated rainfall datasets to drive a numerical model and conducted simulations to determine the most effective interpolation technique. Specifically, we compared Ordinary Kriging interpolation (with search radii of 3, 6, and 9, denoted K3, K6, and K9), Inverse Distance Weighting (I3, I6, and I9), and Spline interpolation (S3, S6, and S9) under various search radius settings. The results indicate that K3, I3, I6, and I9 avoid negative values in the interpolated rainfall fields. The urban inundation simulations reveal significant differences (exceeding 10
