Porosity is the ratio of the volume of void space to the total volume of the rock or earth material.
Porosity is the voids or openings of the rock or soil and is sometimes expressed as a percentage. Effective porosity is the void volume that contributes to water movement and is roughly equivalent to specific yield.
Why is porosity important?
Porosity is an indication of the amount of water in the subsurface, but does not equate to the volume that can be released from storage.