Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
Groundwater residence time and nitrate contamination in shallow aquifers formed in basin Cretaceous sedimentary fills
Abstract
The dynamics of the groundwater circulation were studied in two catchment areas of the Bohemian Cretaceous Basin edge in central part of the Czech Republic and one catchment area located in the northern part of the Třeboň Basin in the southern Bohemia. Both of the studied areas are affected with extensive agriculture exploitation. Groundwater nitrate content together with CFCs, SF6, oxygen stable isotopes and tritium activity were used to estimate the proportion of modern water in springs and wells. The average period of groundwater residence time in the Bohemian Cretaceous Basin ranges from 10 to 35 years (including non-saturated zones). The average period of groundwater residence time in the N part of the Třeboň Basin from V-23 borehole varies from 35 to 45 years.
