In the BH2_Wells data view Reference Elevation is the elevation data that is used in the calculation of Water Elevations. Reference Elevation can be either Top of Casing (from Wells table) or Elevation (from Locations table) if the TOC is not entered.
Wells table Reference elevation will use TOC if entered, otherwise will use the Elevation data entered via the Locations import template, and correct for Stickup (if entered).