Glossary
NAVD 88
NAVD 88 (National Geodetic Vertical Datum of 1988) is the orthometric-height system behind much modern US mapping and surveying. Stage reported "feet NAVD 88" is measured relative to that national surface—not to NGVD 29 unless a source converts explicitly.
Published May 16, 2026 · Editorial standards
Why it matters
Recreation planners, GIS teams, and anglers comparing today's stage to a topo contour all need the same vertical reference. NAVD 88 is the label you will see on newer benchmarks, many LIDAR-derived surfaces, and an increasing share of inland water products.
When a neighbor quotes a Thurmond elevation in NGVD 29 and your app shows NAVD 88, you are not necessarily looking at different water—you may be looking at different zeros.
Technical context
NAVD 88 replaced NGVD 29 as the preferred national vertical datum for many applications after the 1988 adjustment. Heights are orthometric: they follow Earth's gravity field through a geoid model, not a single tide gauge reading.
| Situation | Practical note |
|---|---|
| Legacy USACE tables | May still list NGVD 29 for conservation and flood pools |
| Modern mapping | Often NAVD 88—check the metadata on the layer |
| Gauge API fields | Datum is usually explicit in the product documentation |
On real lakes
Related lake intelligence
Caesar Creek Lake
/lakes/caesar-creek
Caesar Creek Lake catalogs datum NGVD29 and elevation reference MSL—compare only to readings using the same labels.
Related lake intelligence
Taylorsville Lake
/lakes/taylorsville-ky
Taylorsville Lake catalogs datum NGVD29 and elevation reference MSL—compare only to readings using the same labels.
Related lake intelligence
Lake Athens
/lakes/athens-tx
Explore Lake Athens for live levels and the vertical reference published on its lake page.
- Is NAVD 88 the same as mean sea level?
Related through the geoid, but not interchangeable wording on a pool chart. See MSL for coastal charting vs inland operating elevations.
- Which datum does Lake Insights use?
Each lake inherits the datum published with its operating data and catalog metadata. Open the lake page and read the level reference beside thresholds and history.
Related terms: Datum · NGVD 29 · MSL · Elevation reference · Gauge
Reference information only. See data sources, editorial standards, or suggest a correction.