sitelevel

Sitelevel refers to the elevation reference surface used at a construction or surveying site from which other elevations are measured. It is not a universal standard but a project-specific datum chosen to suit local conditions and design requirements. The site level may be tied to a fixed benchmark or to a geodetic vertical datum such as mean sea level, depending on the scope of work and local practice.

Establishing a site level involves leveling surveys: establishing control points with known elevations, and using instruments such as a dumpy level, an automatic level, a theodolite with a level staff, or a modern total station. Measurements are taken at critical points to determine grade, cut and fill, drainage, and foundation elevations. The resulting site level guides excavation depths, concrete slab thicknesses, and the placement of utilities. It is often documented on construction drawings as finish grade or site datum and can be described in meters or feet.

Variations exist: for larger projects, several site levels or a single project-wide vertical datum may be used; for precision work, adjustments may be made for local subsidence or compaction. The term is related to bench marks, vertical datum, site grading, and leveling.

See also: leveling, vertical datum, benchmark, grade, construction surveying.