Non-destructive digging (NDD) is also known as vacuum excavation or hydro excavation. This is a form of digging that ensures tree roots, pipes, cables or anything buried underground are not damaged when you dig around their vicinity. The damage caused to the things buried underground is very minimal compared to what could be the case if you were digging using a crowbar or an excavator.
Difference Between Non-Destructive Digging, Vacuum Excavation and Hydro Excavation
There is a small difference between these three types of excavation. The differences relate to the amount of water pressure used in each method and whether water is actually used to dig up the dirt.
How Non-Destructive Digging (NDD) Works
NDD uses a high-pressure jet of water from a gun/lance. The water is emitted at very high pressure and when pointed to the ground, digs up the dirt and turns it into mud. When the dirt has been dug up, a high-velocity vacuum is used to suck it up, which in turn leaves an excavated hole.
Check the video below for an overview of NDD.