Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 21, 6153-6165, 2017
https://doi.org/10.5194/hess-21-6153-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
07 Dec 2017
The potamochemical symphony: new progress in the high-frequency acquisition of stream chemical data
Paul Floury1,2, Jérôme Gaillardet1, Eric Gayer1, Julien Bouchez1, Gaëlle Tallec2, Patrick Ansart2, Frédéric Koch3, Caroline Gorge1, Arnaud Blanchouin2, and Jean-Louis Roubaty1 1Institut de Physique du Globe de Paris (IPGP), CNRS and Université Sorbonne Paris-Cité, 1 rue Jussieu, 75238 Paris, France
2UR HBAN, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture, Antony (IRSTEA), France
3Endress+Hauser SAS, Huningue, France
Abstract. Our understanding of hydrological and chemical processes at the catchment scale is limited by our capacity to record the full breadth of the information carried by river chemistry, both in terms of sampling frequency and precision. Here, we present a proof-of-concept study of a lab in the field called the River Lab (RL), based on the idea of permanently installing a suite of laboratory instruments in the field next to a river. Housed in a small shed, this set of instruments performs analyses at a frequency of one every 40 min for major dissolved species (Na+, K+, Mg2+, Ca2+, Cl, SO42−, NO3) through continuous sampling and filtration of the river water using automated ion chromatographs. The RL was deployed in the Orgeval Critical Zone Observatory, France for over a year of continuous analyses. Results show that the RL is able to capture long-term fine chemical variations with no drift and a precision significantly better than conventionally achieved in the laboratory (up to ±0.5 % for all major species for over a day and up to 1.7 % over 2 months). The RL is able to capture the abrupt changes in dissolved species concentrations during a typical 6-day rain event, as well as daily oscillations during a hydrological low-flow period of summer drought. Using the measured signals as a benchmark, we numerically assess the effects of a lower sampling frequency (typical of conventional field sampling campaigns) and of a lower precision (typically reached in the laboratory) on the hydrochemical signal. The high-resolution, high-precision measurements made possible by the RL open new perspectives for understanding critical zone hydro-bio-geochemical cycles. Finally, the RL also offers a solution for management agencies to monitor water quality in quasi-real time.

Citation: Floury, P., Gaillardet, J., Gayer, E., Bouchez, J., Tallec, G., Ansart, P., Koch, F., Gorge, C., Blanchouin, A., and Roubaty, J.-L.: The potamochemical symphony: new progress in the high-frequency acquisition of stream chemical data, Hydrol. Earth Syst. Sci., 21, 6153-6165, https://doi.org/10.5194/hess-21-6153-2017, 2017.
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Short summary
We present a new prototype lab in the field named River Lab (RL) designed for water quality monitoring to perform a complete analysis at sub-hourly frequency of major dissolved species in river water. The article is an analytical paper to present the proof of concept, its performances and improvements. Our tests reveal a significant improvement of reproducibility compared to conventional analysis in the laboratory. First results are promising for understanding the critical zone.
We present a new prototype lab in the field named River Lab (RL) designed for water quality...
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