Subsidence Posted on 22nd December 20156th May 2021 by ThePD (The Project Definition) Subsidence is the process by which land or buildings sink to a lower land surface level. 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 Engineering and tagged civil, csa. 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.