The groundSurfaceElevation is a reference datum for converting depth-to-water measurements into groundwater elevation values used in potentiometric surface maps. Field technicians measure water depth from the top of casing; subtracting that from tocElevation gives water elevation. The groundSurfaceElevation is typically established by professional survey at installation and does not change unless the well is resited.
Technical section
Data model, API, and internals — visible to developers.