AQUATIC RESOURCES OF ILLINOIS 8
Types of aquatic resources
Groundwater
When precipitation (rain, snow, sleet) falls to
the ground, some of it runs off, some of it
evaporates and some of it soaks into the soil.
The water that soaks into the soil fills the
cracks and other openings between soil and
rock particles. It can move down far enough
that large underground pools of water form.
This water deep under the ground is called
groundwater. It may remain under the ground
for years, or it may flow into water wells drilled
into the ground. It can also flow out of the
ground at springs. A spring is a place where
groundwater comes out of the earth.
Groundwater is affected by the type of soil in
the area. It soaks in and moves slowly in clay
soils (0.06 inches per hour) because the
particles in clay soils are packed tightly
together. Water can soak into and move
quickly through sandy soils (more than 20
inches per hour) because the soil particles
are very loosely arranged.
About half of the people in Illinois use
groundwater from water wells for drinking.
Almost all of the people (98 percent) who live
in rural areas of the state draw their drinking
water from wells. Water wells range in depth
from 20 feet to more than 2,800 feet. The
depth is determined by how deep the well
must be drilled to reach the groundwater.
Even though it’s deep under the ground,
groundwater may be polluted. In some areas
of Illinois, the groundwater is contaminated
with natural minerals, like calcium and
magnesium, which make the water "hard."
Gasoline and other harmful liquids sometimes
leak from underground storage tanks into
groundwater. Landfills and septic systems
can also add pollutants to groundwater, as
can runoff from fertilized fields, livestock
areas, abandoned mines, salted roads and
industrial areas. Even homeowners can
contribute to groundwater pollution by
pouring household chemicals on the ground.
In 1987, the Illinois General Assembly passed
the Illinois Groundwater Protection Act. This
law is meant to help stop pollution of
groundwater sources. Several state agencies
work to make sure that the law is being
carried out. Those agencies include the
Illinois Environmental Protection Agency,
Illinois Department of Natural Resources,
Illinois Department of Public Health, Illinois
Pollution Control Board and the Office of the
State Fire Marshal.
Ground Water
When precipitation (rain, snow, sleet) falls to
the ground, some of it runs off, some of it
evaporates and some of it soaks into the soil.
The water that soaks into the soil fills the
cracks and other openings between soil and
rock particles. It can move down far enough
that large underground pools of water form.
This water deep under the ground is called
ground water. It may remain under the ground
for years, or it may flow into water wells drilled
into the ground. It can also flow out of the
ground at springs. A spring is a place where
ground water comes out of the earth.
Ground water is affected by the type of soil in
the area. It soaks in and moves slowly in clay
soils (0.06 inches per hour) because the
particles in clay soils are packed tightly
together. Water can soak into and move
quickly through sandy soils (more than 20
inches per hour) because the soil particles
are very loosely arranged.
About half of the people in Illinois use ground
water from water wells for drinking. Almost all
of the people (98 percent) who live in rural
areas of the state draw their drinking water
from wells. Water wells range in depth from
20 feet to more than 2,800 feet. The depth is
determined by how deep the well must be
drilled to reach the ground water.
Even though it’s deep under the ground,
ground water may be polluted. In some areas
of Illinois, the ground water is contaminated
with natural minerals, like calcium and
magnesium, which make the water “hard.”
Gasoline and other harmful liquids sometimes
leak from underground storage tanks into
ground water. Landfills and septic systems
can also add pollutants to ground water, as
can runoff from fertilized fields, livestock
areas, abandoned mines, salted roads and
industrial areas. Even homeowners can
contribute to ground water pollution by
pouring household chemicals on the ground.