Island Hwy Artesian Well EarthCache
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This EarthCache features an artesian well located next to the
Island Highway. It is within the North Central Region of Vancouver
Island, a little ways north of Campbell River.
Aquifers in British Columbia
Ground water provides 23 percent of the province's population with
drinking water, comprises 9 percent of total water consumption in
the province and represents 25 percent of the ground water use in
the nation. It has been recognized for a number of years that a
greater understanding of the existence and characteristics of
aquifers in British Columbia is essential.
Most of the ground water extracted on Vancouver Island comes from
aquifers within the unconsolidated deposits which are recharged by
infiltration of either precipitation or surface water sources. The
amount of water that can be extracted by individual wells
constructed in these aquifers, depends on the permeability of the
aquifer materials, the thickness and extent of the aquifer, the
rate of aquifer recharge and on well construction. The
unconsolidated deposits which are hydrogeologically the most
significant in terms of ground water potential are primarily
comprised of sand and/or gravel.
In some areas ground water is the only viable and economic source
of water supply for individual and community water supply systems
as well as augmenting agricultural and industrial uses. Ground
water often maintains base flows in rivers and streams during
periods of drought and is critical to fisheries habitat and
spawning areas.
Some basics on Artesian wells and artesian aquifers:
Artesian wells were named after the former province of Artois in
France, where many artesian wells were drilled by Carthusian monks
since 1126. The technique was also known much earlier in Syria and
Egypt, although whether the monks of Artois learned of it from
outside sources or discovered it independently is unknown.
An artesian aquifer is a confined aquifer containing groundwater
that will flow upwards out of a well without the need for pumping.
An aquifer provides the water for an artesian well. An aquifer is a
layer of soft rock, like limestone or sandstone, that absorbs water
from an inlet path. Porous stone is crushed between impermeable
rocks or clay. This keeps the pressure high, so when the water
finds a hole, it overcomes gravity and goes up instead of
down.
Why is a well Artesian?
In recharging aquifers, this happens because the water table at its
recharge zone is at a higher elevation than the head of the
well.
Pascal's law predicts the theoretical hydrostatic pressure P:
where ? (rho) is the density of the fluid, g the acceleration due
to gravity, and z is the elevation. In practical terms the pressure
is expressed as metres water column (zr - zw).
"Fossil water" aquifers can also be artesian if they are under
sufficient pressure from the surrounding rocks. This is similar to
how many newly tapped oil wells are pressurized.
To log this cache, you will first have to fullfill a few
requirements.
1) Take a photo of you or your group at the EarthCache location,
and post it with your log.
2) Take a close up photo of your GPSr and one of the artesian well
pipes together. Your latitude and longitude must be readable in the
photo. Post it with your log.
3)Identify 2 different species of plants, trees, and/or wildlife
you saw at the location. Email me their common and scientific
names.
4)Measure the flow rate of one of the wells. Do this by filling a
small container of known volume and timing how long it takes to
fill it. Then convert your time into minutes to tell me approx. how
much water is flowing out in one minute.
5)Taste the water and tell me if you enjoyed it.
Additional Hints
(No hints available.)