Fluid Mechanics of an Artesian Well
The water in an artesian well flows from an aquifer, which is a
layer of very porous rock or sediment, usually sandstone, capable
of holding and transmitting large quantities of water. The geologic
conditions necessary for an artesian well are an inclined aquifer
sandwiched between impervious rock layers above and below that trap
water in it. Water enters the exposed edge of the aquifer at a high
elevation and percolates downward through interconnected pore
spaces. The water held in these spaces is under pressure because of
the weight of water in the portion of the aquifer above it.
If a well is drilled from the land surface through the overlying
impervious layer into the aquifer, this pressure will cause the
water to rise in the well. In areas where the slope of the aquifer
is great enough, pressure will drive the water above ground level
in a spectacular, permanent fountain. Artesian springs can occur in
similar fashion where faults or cracks in the overlying impervious
layer allow water to flow upward. Water from an artesian well or
spring is usually cold and free of organic contaminants, making it
desirable for drinking.
Don't forget to smell the water!
The water from this well has the strong odor of sulphur, hence
the name SULPHUR WELL. The origin of the smell is HYDROGEN
SULFIDE gas.
Hydrogen sulfide gas occurs naturally in some groundwater. It is
formed from decomposing underground deposits of organic matter such
as decaying plant material. It is found in deep or shallow wells
and also can enter surface water through springs, although it
quickly escapes into the atmosphere. Hydrogen sulfide often is
present in wells drilled in shale or sandstone.
While the 'rotten egg' smell may be offensive to some, the water
is safe to drink unless extremely high levels of sulfate minerals
exist, which is extremely rare.
More information on Artesian wells can be found here:
http://en.wikipedia.org/wiki/Artesian_aquifer
LOGGING YOUR VISIT
To log this EarthCache, post a photo of your GPSr at the well.
Additionally, and to demonstrate the educational value of this EC,
please email answers to the following questions:
1. Estimate of the rate at which the well is producing.
This can be done by bringing a container of known volume along with
you and then timing how long it takes to fill that container.
Multiply this number by 2 since the water flows from two different
outlets.
2. Estimate the height above the other nearby water
source (the creek surface) at which the well is producing, and
3. How high is the geiser of water at the well head
(estimate)?.
4. How does it taste? (ok, just kidding, don't.)
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your answers to :
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not wait on a reply from me. FOUND IT logs which do not meet
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