Profile of USGS RDB text format. Scope is Site-based groundwater level data serialization. Columns include: Agency code, USGS site number, Site type code, Date level measured, Time level measured, Time datum, Water-level value in feet below land surface, Water-level value in feet above specific vertical datum, Referenced vertical datum, Status, Measuring agency code, Water-level date-time accuracy code, , Water-level accuracy code, Source of measurement code, Method of measurement code,Water-level approval status code https://n2t.net/ark:/23942/g2800013