Contribution of time tracers (Mg²⁺, TOC, δ¹³C_TDIC, NO₃⁻) to understand the role of the unsaturated zone: A case study—Karst aquifers in the Doubs valley, eastern France

Abstract

Time tracers (NO3−, TOC, δ13CTDIC, Mg2+) have been used to define the hydrodynamic behavior of a karst system: high values in NO3− and TOC reflect rapid infiltration and consequently a short residence time within the aquifer, whereas enriched δ13CTDIC and high Mg2+ 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 δ13CTDIC 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.

Use of stable isotopes to quantify flows between the Everglades and urban areas in Miami-Dade County Florida

“…These exceptions were characterized by groundwater with isotopic signatures similar to that of rainfall, again suggesting isolated areas where rapid infiltration occurs. Furthermore, it is emphasized that the rapid and localized infusion of rainwater at G-3663 is consistent with karst aquifer flow conditions (Celle-Jeanton et al, 2003;Gabrovšek and Dreybrodt, 2001;Siemers and Dreybrodt, 1998;and others). Jones and Banner (2003) for example found consistently among three tropical karstic aquifers that recharge occurs by rapid infiltration with little evaporation.…”

Microorganisms as contaminants and natural tracers: a 10-year research in some carbonate aquifers (southern Italy)

“…Most groundwater tracers used for hydrogeological purposes in carbonate aquifers are mainly chemicals and isotopic (e.g., Celle-Jeanton et al 2003;Andreo et al 2004;Aquilina et al 2006). They are used to determine the water origin, groundwater directions, velocities of subsurface flow, etc.…”

Conceptual hydrogeological model of flow and transport of dissolved organic carbon in a small Jura karst system

“…A collective calibration procedure was carried out on the calibration set, with firstly, an optimisation of the discharge simulation using Nash-Sutcliffe's coefficient of efficiency NS, and secondly, an optimisation of the chemograph simulation using the determination coefficient R 2 . For collective calibration, the NS criterion for N events is expressed according to Chahinian et al (2006) as follows:…”

“…Due to the high input in organic soil substances in infiltrated water, organic carbon (OC) -which may be present in particulate (POC) or dissolved (DOC) form -is an interesting tracer of infiltration in karst systems (Emblanch et al, 1998;Batiot et al, 2003;Celle-Jeanton et al, 2003;Mudarra and Andreo, 2011). OC is a non-conservative tracer whose mineralization over time occurs at the scale of a few weeks (Batiot, 2002), meaning that it is a useful tracer of fast infiltration.…”