Impacts of Emergent Vegetation on Hyporheic Exchange
Shih‐Hsun Huang, Judy Q. Yang
Abstract
Abstract Hyporheic exchange, or the exchange of water and solutes between surface and subsurface water at the sediment‐water interface, regulates water quality and biogeochemical cycle in aquatic ecosystems. Vegetation, which is ubiquitous in nature, is known to impact hyporheic exchange; yet how vegetation impacts hyporheic exchange remains to be characterized. Here, we show that at the same spatially and temporally‐averaged flow velocity , vegetation increases the rate of hyporheic exchange by a factor of four. By tracking the movement of fluorescent dye in a flume with the refractive‐index‐matched sediment and translucent vegetation dowels, we demonstrate that the vegetation‐induced hyporheic exchange can be characterized by an effective hyporheic exchange velocity, . We further demonstrate that correlates with the total near‐bed turbulent kinetic energy rather than , when , indicating that turbulent kinetic energy is a better metric than flow velocity for predicting hyporheic exchange in regions with vegetation.