Author(s): Jingwen Xing; Yi Cai; Nianqing Zhou
Linked Author(s):
Keywords: Hyporheic exchange hyporheic zone tidal action seasonal hydrological changes riverbed-riparian continuum
Abstract: The hyporheic zone is essential for maintaining the health of river ecosystems, serving as a vital area for the interaction between river water and groundwater as well as the bio-geochemical action driving nutrient cycle. For coastal rivers, the hyporheic exchange is usually more frequent and more complex, under the combined effects of tidal action and seasonal hydrological conditions. In this study, the two-dimensional numerical model of the riverbed-riparian continuum was established to evaluate the impacts of tidal intensity and seasonal hydrological variations on the hyporheic exchange flux and the extent of the hyporheic zone. The results show that, both the hyporheic exchange volume and the hyporheic zone width increase gradually, as the amplitude of river water stage fluctuation increases. Additionally, varying with the season, the primary direction of hyporheic exchange shifts from river recharge to groundwater in the wet season to groundwater recharge to river in the dry season. Moreover, during the transition from wet to dry season, the hyporheic exchange volume initially decreases and then increases, while the hyporheic zone width gradually decreases. The findings can provide scientific insights for the ecological restoration of rivers in coastal areas.
Year: 2025