Qualité et vulnérabilité des eaux souterraines profondes

Institut de Géodynamique, Université Michel de Montaigne, Bordeaux 3

Abstract

Deep groundwaters are nowadays more and more sollicitated for the human use. At the very simple scheme of a monoaquifer confined under an acquiclude one tends to substitute since some years a more realistic scheme of a of multilayers systeme with leakage.

Except the case of karsts, the deep aquifers of large and regional extension are described as large stocks and weak flux. The residence time of water may be very long (many thousand years) and this quality of groundwater related to the nature of the reservoir is stable.

The vulnerability to the pollution may be sometimes important in the outcrops emergence and/or rechange zones - but not significant in deep parts. However, some special uses can generate exchanges front bed to bed so that the quality may be locally modified.