Technical
NAVD88
North American Vertical Datum of 1988
Definition
NAVD88 is the official elevation reference standard used for all permitted coastal and waterfront construction in Florida.
What it means in practice
NAVD88 replaced the older NGVD29 datum and is now the required vertical reference for FDEP permits, USACE filings, FEMA flood maps, and most marine construction work in Florida. Elevations are expressed as feet above or below the datum — for example, a dredged channel depth might be stated as '-6.0 NAVD88,' meaning six feet below the reference plane.
Why it matters to you
Every dredging quote, bathymetric survey, and permit drawing in Florida should reference NAVD88. If a contractor gives you a depth in 'mean low water' or any other reference, ask for a NAVD88 conversion. Without it, you cannot verify against permit conditions, FEMA flood elevations, or your original design drawings.
Related terms
Have a project that involves NAVD88? Talk to us.
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