LADES
Espace performance
Batiment C1-C2
35769 Saint Gregoire

Phone. +33 2 99 23 74 40
Fax. +33 2 99 23 78 11
Mail : info lades.fr

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The European Water Framework Directive highlights the importance of good knowledge of water mass. Age is the key parameter to estimate the time needed to reach a good chemical status according to change in surface practices.

Groundwater age gives estimation of dissolved elements age

Chemical elements move underground with groundwater. According to the retardation factor correction, the age of elements is equivalent to the age of water. This is the case for nitrates which have a retardation factor near 1. Knowing groundwater age allows estimating nitrates age in the drinking well and the river and thus modeling the nitrate concentration evolution according to the present and the past changes.

Envisaging chemical evolution according to different scenario

The groundwater age allows estimating the water velocity, transfer time underground. These data help identifying results of different scenario in agricultural or industrial practices at a given point. Only one analysis on a catchment helps defining hypothesis but studies on more points on the watershed and knowledge on past agricultural practices greatly enhance the confidence in the interpretation of the results.