What is a cone of depression and how is it caused?

"The water table is drawn down, or depressed, in the vicinity of a borehole from which groundwater is being abstracted by pumping. Groundwater is pumped from a well. In an unconfined aquifer (water table), this is an actual depression of the water level." The cone of depression is a reduction in the pressure head surrounding the pumped well.

Answer8.0m;