About Aquifer Vulnerability Maps
vulnerability of an aquifer is a measure of its risk of contamination. Aquifer vulnerability is determined by
combining susceptibility ratings with human sources and natural sources of
contamination. Vulnerability therefore
differs from aquifer susceptibility, which considers only the physical factors
that affect flow into and through an aquifer, without regard to threats to
ground water from human sources or natural sources of contamination. (See the description of aquifer susceptibility
in a separate section of this web site).
(risk) typically is greater where human development occurs, especially on the
recharge area of an aquifer or near creeks upstream from sinkholes. Examples of development can include roads and
streets, homes, septic systems, industrial activities, agricultural activities,
and mining. When factors such as these
are combined with a high susceptibility rating, the result typically is a high
vulnerability of the aquifer to contamination.
map at the left shows the outcrop of the Madison aquifer with various colors
that indicate ratings of its vulnerability.
These ratings depend on the following factors: 1) the aquifer’s very high susceptibility,
and 2) roadways, homes with septic systems, and other human factors that vary
from place to place.