What are artisan wells characterized by?

Artisan wells are characterized by water that is naturally occurring and free-flowing. This occurs because the water is under pressure in a confined aquifer, meaning that when a well is drilled, the water rises to the surface without the need for pumping. This phenomenon is a result of the geological formations that trap water under pressure, and it distinguishes artisan wells from other types of wells that often require mechanical pumping to access groundwater.

In contrast, options indicating that water is pumped mechanically do not apply to artisan wells since they flow naturally due to internal pressure. The mention of extensive drilling is more pertinent to other well types, such as deep wells, rather than artisan wells that often require less drilling to reach the pressurized water source. Lastly, while underground rivers are a source of groundwater, artisan wells are not limited to water found only in those locations; rather, they can tap into various types of confined aquifers.