A cone of depression can form if:

A) groundwater is overpumped from an aquifer
B) limestone caverns collapse
C) an artesian well goes dry

Cone of Depression

A cone-shaped lowering of the water table around a pumping well, due to the removal of groundwater faster than it can be replenished.

Overpumped

A term usually related to groundwater resources, indicating a condition where water is removed from an aquifer at a rate faster than it can be replenished.

Aquifer

An underground layer of water-bearing permeable rock, rock fractures, or unconsolidated materials (gravel, sand, silt) from which groundwater can be extracted.