[关键词]
[摘要]
河流潜流带是河水与地下水发生物质能量交换的区域。河床沉积物的渗透系数影响着其间水力联系的强弱和潜流带水量交换大小。淤塞-反淤塞作用改变着河床的渗透性能。通过对近年来国内外学者对潜流带淤塞-反淤塞不同作用期河床渗透系数变化的研究总结。认识到渗透系数大小不仅决定于沉积物空隙的直径大小,而且与潜流带水文连通性和生物扰动作用紧密相关,洪水带来的细小颗粒引起河床表面沉积物淤塞,致使渗透系数减小,但在洪水退后,潜流带的水文交换和生物扰动能破坏淤塞层,从而引起反淤塞作用,引起河床渗透系数增大。而上述这些研究仅仅限于渗透系数实测数据变化基础上的理论分析,如何深入地解析潜流带淤塞-反淤塞作用下渗透系数的变化机理,尚需要做大量研究工作。
[Key word]
[Abstract]
The hyporheic zone plays a key role in the surface water and groundwater interaction. Streambed hydraulic conductivity can affect the magnitude of interactions between groundwater and surface water and hyporheic water exchange. The clogging and declogging processes often occur alternately, which can change the streambed sediment characteristics and affect its permeability. On the basis of the overview of literatures of hyporheic exchange and streambed hydraulic conductivity, the possible effects of clogging and declogging processes on the streambed hydraulic conductivity have been illustrated. Streambed hydraulic conductivity is not only affected by the pore size of sediments, but also related to the hydrological connectivity and bioturbation in the hyporheic zone. Generally, the small particles brought by the floods can cause riverbed clogging, resulting in reduced hydraulic conductivity. However, when the flood goes down, hydrological exchange and bioturbation in the hyporheic zone can destroy the clogging layer, causing the declogging process and increasing in hydraulic conductivity. The current studies are limited to the analysis of the variations of measured streambed hydraulic conductivity data, and the mechanism of the clogging and declogging processes in the hyporheic zone of a river requires more investigations.
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[基金项目]
基金项目:国家自然科学基金(51079123);教育部新世纪优秀人才支持计划项目(NCET-11-1045);教育部留学科研启动基金(教外司留[2010]1174)。