Short-term variations in tracer tests responses in a highly karstified watershed

Variations à court terme de la réponse d’essais de traçage dans un bassin d’alimentation très karstifié

Vianney Sivelle (1) , David Labat (1)

1 GET - Géosciences Environnement Toulouse

Modelling non-reactive solute transport based on artificial tracer tests have been widely used in the past decades. The dependence of solute transport from boundary conditions have been investigated across different hydrological conditions (low and high-water level) but still not investigated on short-term scale (i.e. hourly and daily scale). In this study, a campaign of several tracer tests is performed on a few days to investigate the short-term variations of tracer tests responses in a conduit dominated kart system during a recession without the influence of rainfall. Also, an improved artificial tracer test interpretation using a process engineering tool is introduced. It consists of a Laplace-transform transfer function approach of the residence time distribution curve. Considering the karstic system as a chemical reactor, the introduction of a transfer function approach appears to be an efficient way to describe the solute transport. Moreover, the transfer function is parametrized depending on the spring discharge. Finally, the model is extended to deal with source pollution scenario testing.

Mots clés: artificial tracer test; karstic system; transfer function; pollution scenario

Domaines: Milieux et Changements globaux; Hydrologie

Vianney Sivelle, David Labat. Short-term variations in tracer tests responses in a highly karstified watershed. Hydrogeology Journal, 2019, 27 (6), pp.2061-2075. ⟨10.1007/s10040-019-01968-3⟩. ⟨hal-03239276⟩