Poster De Conférence Année : 2025

Dissolved carbonate exports in the Chevaline river (Choranche, Vercors). Period 2008–2018

Résumé

Here we present some preliminary results on the export of dissolved carbonates in a mid-mountain underground river: Chevaline (Vercors, France). A hydrometric station (2008–2018) records water levels, temperatures, and conductivities (every 30 minutes). Water levels are converted into flow rates and conductivity is converted into dissolved carbonate concentrations. This allows us to calculate dissolved carbonate flow rates. The underground river is subject to significant encrustation. Some of the calcite is deposited upstream of the measuring station and some far downstream. The measurements we propose do not account for all the dynamics of karst dissolution. However, they do allow us to analyze the dissolved export downstream of this mid-mountain karst system. The flow distribution shows a strong asymmetry with flows varying from 0 to 3.6 m3/s. The median is 37.7 l/s. The same distribution of dissolved carbonate exports is observed with carbonate flows ranging from 0 to 880 g/s. The amplitude of carbonate concentrations is limited to between 186 and 296 mg/l. It is the quantity of water that controls carbonate flows, not the carbonate content. We then analyze the evolution of dissolved exports over 10 years. Dissolved carbonate exports show variations ranging from single to double during this period (min: 415 t, max: 923 t). We then recalculate these dissolved exports according to the four hydrological situations of equal duration: low water, low flow, high flow, and floods. Floods represent an average of 25% of the hydrological time over 10 years. They account for 63% to 78% of chemical erosion.

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Dates et versions

hal-05126696 , version 1 (24-06-2025)

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  • HAL Id : hal-05126696 , version 1

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Stéphane Jaillet, Jean-Jacques Delannoy, Jean-Luc Peiry, Yves Perrette, Emmanuel Malet, et al.. Dissolved carbonate exports in the Chevaline river (Choranche, Vercors). Period 2008–2018. 32 th International Karst School, Jun 2025, Postojna, Slovenia. ⟨hal-05126696⟩
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