Author(s): V. Thiercelin; C. Berni; L. Gostiaux; L. Kateb; E. Mignot; N. Riviere
Linked Author(s): Celine Berni
Keywords: Transverse mixing; Experimental study; Hydrogeomorphology; Pollutant transport; Riffle-pool
Abstract: In the event of a local release of a pollutant in a river, it will initially remain concentrated in a small zone before being fully mixed across the width. Improving the estimation of the mixing zone of industrial inflows in rivers is essential to assess the impact on water quality and the sustainability of aquatic ecosystems. This zone is defined as the distance from the release section to the section where the pollutant is uniformly distributed. It can be calculated by applying an advection-diffusion model based on the estimation of a transverse mixing coefficient Ey [m2/s] (Huai et al., 2018). Numerous formulas exist to estimate it (Aghababaei et al., 2017; Baek & Lee, 2023; Jeon et al., 2007) but most have only been validated for specific river configurations. As demonstrated in recent literature reviews (Baek & Lee, 2023; Huai et al., 2018), no riffle-pool configuration has been considered to date. Furthermore, the transverse mixing coefficient is observed to vary according to the facies of the section studied (Gond et al., 2021), thereby confirming the hypothesis of transverse mixing processes specific to riffle-pool conditions. The objective of this study is then to measure the transverse mixing coefficient in riffle-pool configurations both in the field and in a dedicated laboratory experiment.
Year: 2025