Excavation is removing material from a construction site or other area to make room for new structures, additions, and features. Different methods of excavation can be used depending on the terrain, size of the project, and budget. 

These include manual labor with tools such as shovels and picks, motorized equipment like bulldozers and loaders, hydraulic systems including pneumatic drills and dredges for heavy-duty work, explosives for large-scale projects that require the quick removal of soil or rock layers, trenchless technology like horizontal directional drilling which uses pressurized water to bore through materials without disturbing surface level ground coverings. 

Manual labor is often preferred due to its low cost, while motorized machinery can quickly take care of large areas but may disturb existing ecosystems. Hydraulic systems are useful when working in confined spaces with little room for larger machinery, while explosives are great options when speed is an issue. Trenchless technologies offer minimal disruption while accomplishing desired tasks at relatively high speeds, making them advantageous over traditional excavation techniques in many cases.