Dissolution in a porous rock: effect on the concentration–discharge relationships
Résumé
Various empirical or physically-based theory have been proposed to understand how the solute concentration of a stream varies with the discharge. We focus here on the influence of the dynamics of the groundwater flow on the chemical erosion rate. To do so, we couple a one-dimensional aquifer model to a first order dissolution equation. If the aquifer extends far below the stream level, the theoretical discharge–concentration equation corresponds to the empirical " working model " proposed by Johnson in 1969, thus providing a physical interpretation of its parameters. Conversely, if the aquifer lays mainly above the stream level, a significantly different relationship is found. These theoretical findings are then compared to two field-data sets. From this comparison, we conclude that the dynamics of the groundwater flow could play a significant role in moderating the impact of dilution on the stream concentration at large discharges.
Domaines
GéomorphologieOrigine | Accord explicite pour ce dépôt |
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