ABSTRACT
The extraction of groundwater by artificial means for various purposes is arguably the most
important final stage for the majority of hydrogeologic projects. When surface water, or
treated contaminated groundwater, is injected into the aquifer as part of a project, such as
aquifer recharge or groundwater remediation, in many cases this injection can also be
considered as extraction, but with a negative sign (water is added to the aquifer), because
the basic hydraulic principles and engineering design are quite similar. Probably the first
image that comes to mind to many people when mentioning groundwater extraction and use
in general is that of a well. For nonhydrogeologists and those who are not in a related water
supply profession, well usually means a nondescript hole in the ground that somehow produces
water; this may include an image of a ‘‘mysterious’’ fenced well house, or a picturesque
countryside image of a dug well with a rotating wooden wheel and a bucket. In any case, a
relatively small number of people fully understand the complexity, importance, and cost of a
properly constructed well used for public water supply. The same is true in many developed
countries where modern drilling technologies are routinely used to construct wells for domes-
tic supply: the end users usually leave this ‘‘well business’’ to well drillers and do not care to
learn much about their own ‘‘hole’’ in the ground. Hydrogeologists and groundwater profes-
sionals, however, think of wells in many different contexts, and some of them spend lifetimes
trying to better understand wells and their various interactions with aquifers and ground-
water. The main difficulty in all this is, and will continue to be, a very simple fact: every well is
a hole in the ground (with more or less equipment in it) that cannot be visually examined so
that everything about it has to be determined indirectly.
