Pacific Rim Highway Artesian Well EarthCache
Pacific Rim Highway Artesian Well
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Difficulty:
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Terrain:
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Size: 
(other)
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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
Canada. 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.
Aquifers in British
Columbia
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.
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 hydro geologically 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. These water sources are fragile and cannot be
abused. Such risks include:
- Salt water infiltration is the well is near an ocean
coastline
- Consolidation (compaction) of soil underneath a structure or
entire city (a huge problem in cities such as Beijing and Mexico
City)
- The water table will drop so far that the energy requirement to
pump water upwards would be uneconomical
- You can run out of water and permanently deplete the
aquifer
The History of 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.
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.
"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.
Logging
Requirements
To log this cache, you will first have to fullfill a few
requirements.
1) 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
approximately how much water is flowing out in one minute.
2) Taste the water and tell me if you enjoyed it.
3) Optional: Take a picture
of yourself with the well and your GPS in the photo.
Additional Hints
(No hints available.)