The site is equipped with observation wells that allow
sampling at different depths and distances from the river.
The wells are lined with hard PVC pipes (diameter 5 cm).
Figure 1 shows the situation of the site with the wells used
in this study. The aquifer consists of three layers. The top
layer is freshly infiltrated river water, the middle layer is water
that was infiltrated upstream of the test site, and the lower
layer consists of groundwater that is not affected by infiltra-tion.