Author(s): Jingwen Xing; Yi Cai; Nianqing Zhou

Linked Author(s):

Keywords: Hyporheic exchange; 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 biogeochemical action driving nutrient cycling. For coastal rivers, the hyporheic exchange is usually more frequent and more complex, due to the combined effects of tidal action and seasonal hydrological conditions. In this study, a 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 stage fluctuation increases. Additionally, the primary direction of hyporheic exchange varies seasonally, shifting from river recharge to groundwater during the wet season to groundwater recharge to river during 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.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P1676-cd

Year: 2025