About the Aquifer
The aquifer is in Permian-Cretacic sandstones, covered on at least 90% of its extent by
Jurasic-Cretacic basalts of varying degrees of fracturing/fissuring. Such sandstones
range in thickness from few meters to more than 800 meters (in Río Grande Do Sul,
Brazil). It is basically a confined aquifer, and its main source of recharge is infiltrating
rainfall in those places where the basaltic cover is not present. The groundwater flow is
from the North-East to the South-West, with waters which incorporate solutes along the
flow direction. The average salinity in the recharge area is about 50 mg/l, and can be as
much as 500 mg/l on the South-Western region. The general flow direction matches an
increase in groundwater temperatures, from 22 to up to 60 ºC, which has been mostly
attributed to the effect of the normal geothermal gradient.
