Hubei Key Laboratory of Ecological Restoration of River-Lakes and Algal Utilization, Hubei University of Technology, Wuhan 430068, China.
Foreign Environmental Cooperation Center, Ministry of Ecology and Environment of China, Beijing 100035, China.
Int J Environ Res Public Health. 2022 Oct 4;19(19):12695. doi: 10.3390/ijerph191912695.
The hyporheic zone (HZ) is important for river ecological restoration as the main zone with nitrogen biochemical processes. The engineering of river ecological restoration can significantly change the hydrodynamics, as well as solute transport and reaction processes, but it is still not fully understood. In this study, nitrogen transport and reaction processes were analyzed in the HZ with an in-stream weir structure. An HZ model was built, and three reactions were considered with different design parameters of the weir structure and different permeability characteristics of porous media. The results show that a structure with a greater height on the overlying surface water enables the species to break through deeper porous media. It promotes the mean spatial reaction rates of nitrification and denitrification and results in increased net denitrification in most cases. In addition, increasing the burial depth of the structure leads to the same variation trends in the mean spatial reaction rates as increasing the structure height. Larger permeability coefficients in porous media can enhance flow exchange and increase mean spatial reaction rates. The results can help deepen the understanding of nitrogen transport and transformation in the HZ and optimize the design parameters and location of the in-stream structure.
渗流区（HZ）是河流生态恢复的重要区域，是氮生化过程的主要区域。河流生态恢复的工程可以显著改变水动力条件以及溶质输运和反应过程，但目前仍不完全清楚。在这项研究中，分析了具有明渠堰结构的 HZ 中的氮迁移和反应过程。建立了 HZ 模型，并考虑了三种不同堰结构设计参数和不同多孔介质渗透性的反应。结果表明，上覆水面具有更大高度的结构可以使物种穿透更深的多孔介质。它促进了硝化和反硝化的平均空间反应速率，并在大多数情况下导致净反硝化增加。此外，增加结构的埋藏深度会导致平均空间反应速率呈现出与增加结构高度相同的变化趋势。多孔介质中较大的渗透系数可以增强流动交换并提高平均空间反应速率。研究结果有助于加深对 HZ 中氮迁移和转化的理解，并优化明渠结构的设计参数和位置。
