Contribution of time tracers (Mg2+, TOC, δ13CTDIC, NO3) to understand the role of the unsaturated zone: A case study—Karst aquifers in the Doubs valley, eastern France

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Publication Date

3-1-2003

Publication Title

Geophysical Research Letters

Volume Number

30

Issue Number

6

Abstract

Time tracers (NO 3 − , TOC, δ 13 C TDIC , Mg 2+ ) have been used to define the hydrodynamic behavior of a karst system: high values in NO 3 − and TOC reflect rapid infiltration and consequently a short residence time within the aquifer, whereas enriched δ 13 C TDIC and high Mg 2+ are expected for “old water”. 9 Springs and 5 boreholes have been sampled during three field campaigns in the Doubs valley karst aquifer: low water, flood and recession periods. A clear differentiation can be highlighted between boreholes, characterized by a long residence time, and springs that show a rapid infiltration. Considering only the springs values, it appears that TOC and δ 13 C TDIC contents can easily be correlated to the sampling period. We show then the contribution of the unsaturated zone to the discharge during the low‐water period, and the existence of reserves that seem badly connected to the drainage network, and that contribute poorly to the minimal flow.

Document Type

Article

Digital Object Identifier (DOI)

https://doi.org/10.1029/2002GL016781

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