Cone of depression

A cone of depression is a circular area surrounding a well where groundwater levels are reduced from pumping.

In confined aquifers (artesian), the cone of depression is a reduction in the pressure head surrounding the pumped well.

The amount of water in storage and the thickness of the aquifer also will determine the size and shape of the cone of depression.

As a well is pumped, the cone of depression will extend out and will continue to expand in a radial fashion until a point of equilibrium occurs.

Cones of depression's are typically thought as being a circular feature surrounding the pumped well.

However, in the case of dewatering for mines and landfills where the goal is to lower water levels and pressures, wells often are placed close together in order to reduce head in the aquifer to the maximum amount.

Contour maps of water levels and pressures often show “bulls-eyes” around pumped wells that represent cones of depression.