Artesian wells were named after the former province of Artois in
France, where many artesian wells were drilled by monks starting in
1126. The water in an artesian well comes from an aquifer. An
aquifer is a layer of soft rock, like limestone or sandstone, that
absorbs water from an inlet path. The porous rock of the aquifer is
confined or sandwiched between impermeable layers of rocks or clay,
on both the top and bottom of the aquifer layer. This keeps the
pressure high, so when the water finds a hole, it overcomes gravity
and gets pushed out of the ground. The water flows upwards out of
the well withouth the need for pumping. Another reason that the
pressure of the water is high in the porous layer is because the
“saturation zone” (the crest or the top of the water table) is at a
higher elevation from where the well is located. See those hills to
your northwest? I'll bet this water is coming from there!
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