The Rural Voice, 2001-03, Page 22B, some estimates if
SII tha water below
the surface of the
earth could be spread on
the surface, it would cover
the entire earth to a depth
of 120 metres (400 feet).
By comparison, if all the
water in all the freshwater
lakes and rivers was spread
on the surface of the earth,
it would be just a quarter
metre (10 inches) deep.
In Canada, some six
million people depend on
groundwater for their water
supply. In part of. western
Ontario 90 per cent of
residents on farms and in
towns and villages depend
on water from deep
bedrock aquifers.
And yet we know so
little of what's going on
under the ground.
But slowly, spurred on
by concerns as widespread
as watertaking for bottling
plants to the impact of
modern agriculture,
research is being done that
will widen the knowledge
of what's below the surface
of the land.
Even as new deep wells
are drilled into the bedrock
each year, few people have
any idea where their water
comes from. Hearing about
the vast amounts of water
beneath the surface, some
are apt to think of
underground lakes or
rivers. But while
underground water does
flow from one part of the
country to another, it does
so through cracks and
passages in the materials of
the earth, Environment
Canada explains in its fact
sheet Groundwater —
Nature's Hidden Treasure.
Those who depend on
shallow wells for their
water are usually tapping
into shallow aquifers,
usually sand and gravel
deposits below the topsoil
but above the bedrock.
Water below the surface of
bedrock moves through
18 THE RURAL VOICE
THE WATER DOWN BELOW
Little is known about aquifers, the
immense storehouses of water deep
beneath our feet. New studies are just
now beginning to try to understand the
dangers to this precious resource.
By Keith Roulston
fractures.in the rock. In
granite this may be tiny
crevices and fissures. In
limestone, the water may
actually dissolve the rock
over time, creating
channels and even caverns.
Research into
underground water flows in
the area between the
eastern extremes of the
Maitland Valley watershed
and the Grand River
watershed show
underground channels in
the limestone that take
water eastward toward the
Grand, even though it
would have flowed west to
the Maitland had it been on
the surface, says Jack
MacPherson, hydrologist
with the Maitland Valley
Conservation Authority.
It's generally agreed that
the deep aquifers for the
whole region encompassing
Huron and Bruce counties
are fed from the Dundalk
highlands and move
westward toward Lake
Huron. The speed of the
movement varies greatly.
In some permeable
materials groundwater may
move several metres a day;
in others places where the
materials are relatively
impermeable clay or shale,
it moves only a few
centimetres a century.
Aquifers can vary from
as small as a few hectares
in area to vast sources
covering thousands of
square kilometers of the
earth's surface and may
range from a few metres
thick to hundreds of metres
from top to bottom.
The water in those
aquifers have been
underground for as little as
a few days or weeks
depending on how quickly
the soil absorbs surface
water, but it might be as
much as 10,000 years old.
By comparison, the average
turnover time of river
water, or time it takes the
water in rivers to
completely replace itself, is
about two weeks.
Two major studies in •
mid -western Ontario are
currently under way to try
to understand more about
the aquifers.
The County of Huron
through its Goundwater
Study, funded through the
Ministry of Environment's/
Groundwater Protection
Fund is trying to learn
about the quality of the
water in the aquifers.
Meanwhile it's quantity
that's the focus -of the
AEMOT Groundwater
Study in northeastern Grey
County where the high
demand for water has
created concerns.
In Huron nearly
everyone aside from the
Town of Goderich depends
on well -water, even in the
other towns and villages.
There are some 5500 wells
that are known of, 90 per
cent drilled into bedrock.
Generally the water supply
is good: only six per cent of
the wells surveyed reported
low yield while only four
per cern reported problems
of salty, sulphurous or
mineralized taste.
Huron's diversity
provides the study with
some interesting variety,
leading to studies of 180
wells in six distinct areas.
The southern part of the
county has a much higher
number of shallow wells,
dug or drilled into the
overburden. In the area
south of Clinton and
Seafonh, most of the wells
are bedrock wells but there
are sinkholes that allow a
more direct connection
between surface water and
ground water. In the
Brussels area the bedrock is
closer to the surface, even