Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 7 1 2003 10.5194/hess-7-87-2003 http://www.hydrol-earth-syst-sci.net/7/87/2003/ http://www.hydrol-earth-syst-sci.net/7/87/2003/hess-7-87-2003.html http://www.hydrol-earth-syst-sci.net/7/87/2003/hess-7-87-2003.pdf 87 96 0000-00-00 A standardised method for measuring in situ denitrification in shallow aquifers: numerical validation and measurements in riparian wetlands J. M. Sánchez-Pérez C. Bouey S. Sauvage S. Teissier I. Antiguedad P. Vervier Laboratoire d’Ecologie des Hydrosystèmes (LEH, FRE CNRS-UPS 2630), 29 rue Jeanne Marvig, F-31055 Toulouse Cédex, France Group of Hydrogeology. University of Basque Country – Euskal Herriko Unibertsitatea, 48940 Leioa, Basque Country, Spain Email for corresponding author : sanchez@ecolog.cnrs.fr A tracer test to examine <i>in situ</i> denitrification in shallow groundwater by a piezometer with a packer system used bromide as a tracer of dilution and acetylene (10%) to block the denitrification process at the nitrous oxide stage. During the test, dissolved oxygen, nitrate (NO₃^‾), bromide (Br^‾), nitrous oxide (N₂O) and dissolved organic carbon (DOC) were measured. To calibrate the experimental method, comparison with numerical simulations of the groundwater transfer were carried out, taking into account the environmental characteristics. The method was tested by measurements undertaken in different environmental conditions (geology, land use and hydrology) in two riparian wetlands. Denitrification rates measured by this method ranged from 5.7 10^-6 g N-NO₃^‾L^-1 h^-1 to 1.97 10^-3 g N-NO₃^‾L^-1 h^-1 The method is applicable in shallow aquifers with a permeability from 10^-2 to 10^-4m s^-1.</p> <p style="line-height: 20px;"><b>Keywords: </b>denitrification, shallowaquifer, groundwater modelling, wetlands, nitrate-nitrogen, packer system</p>