Impact of Slightly-Curved Riparian Vegetation Distribution on Hyporheic Lateral Exchange solute migration

Abstract

Abstract Riparian hyporheic exchange has a very important role in blocking and reducing pollution. In order to quantitatively grasp the self-purification ability of the river and predict the change of water quality, it is necessary to have a good understanding of the process that drives river water into the hyporheic layer. In this paper, the effects of slightly-curved riparian and vegetation density on the hyporheic lateral exchange of solute migration were studied in depth through model tests. The results show that: (1) The vegetation spacing d has a significant effect on the hyporheic lateral exchange. As the lateral spacing of vegetation decreases, the rate of hyporheic lateral exchange increases. (2) The amplitude a has a significant effect on the hyporheic lateral exchange. As the amplitude a increases, the faster the hyporheic lateral exchange rate on convex surface, and the larger the feather forward area of solute migration. However, due to the expansion of the volume of the retention area on the concave surface, it has a suppressive effect on the disturbance pressure and delays the solute transport. (3) There is a certain asymptotic limit for the increase of the hyporheic lateral exchange width, when the ratio of the underground pore water concentration C′ to the surface circulating water concentration C0′in the riparian zone is equal to 0.50, the solute transport width can be approximated as a suitable width for the hyporheic lateral exchange. The results are expected to provide a certain reference for the theoretical research of riparian hyporheic exchange.