Aquifer Posted on 2nd November 201516th July 2021 by ThePD (The Project Definition) Aquifer is a geologic formation or structure that is saturated water in the soil or rock below the land surface. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Substance and tagged substance, water. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.