Artesian systems occur where goundwater under pressure rises above
the surface of the aquifer to the artesian pressure surface.
Artesian well - deep drilled well through which water is forced
upward under pressure. 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. In
North America, the Dakota sandstone provides aquifers for an
artesian system that underlies parts of the Dakotas, Montana,
Wyoming, Kansas, Nebraska, and Saskatchewan and supplies great
quantities of water to the dry Great Plains region. Many East Coast
cities derive their water supplies from aquifers that are exposed
along the edge of the Piedmont and dip downward toward the Atlantic
coast. The largest artesian system in the world underlies nearly
all of E and S Australia. Other important artesian systems serve
London, Paris, and E Algeria. To log this Earthcache you must do
two things!
1.If you would like too,But not needed, take a picture of
yourself the GPS and the Thermometer with the well.
2. Tell me(e-mail) the water temperature of the water comming
out of the well you will need a Thermometer.