Glossary
NGVD 29
NGVD 29 (National Geodetic Vertical Datum of 1929) is the older national vertical datum still printed on many USACE pool schedules, legacy gauge histories, and southeastern reservoir guides. Treat any NGVD-labeled elevation as valid only in that reference frame.
Published May 16, 2026 · Editorial standards
Why it matters
Most Savannah River impoundments were designed and operated when NGVD 29 was the federal default. Decades of fishing reports, marina clearance notes, and flood letters still cite those feet values.
If you import a 1980s pool table into a spreadsheet beside a NAVD 88 contour, you need a conversion—not a guess.
Technical context
NGVD 29 is an orthometric datum tied to a network of benchmarks adjusted in 1929–1931. NAVD 88 superseded it for many mapping products, but operations documents often retain NGVD numbers because rule curves and easements were written that way.
On real lakes
Related lake intelligence
Clinton Lake
/lakes/clinton-ks
Clinton Lake catalogs datum NGVD29 and elevation reference MSL—compare only to readings using the same labels.
Related lake intelligence
Lost Creek Lake
/lakes/lost-creek-or
Explore Lost Creek Lake for live levels and the vertical reference published on its lake page.
Related lake intelligence
Lake James
/lakes/james-nc
Lake James catalogs elevation reference Duke full-pond gauge (100.0 = full pond)—compare only to readings using the same labels.
- Should I still record NGVD 29 readings?
Yes—when that is what the authority publishes. Record the value, the datum string, and the date. Convert later with documented tools if you need NAVD 88 for mapping.
Related terms: Datum · NAVD 88 · Full pool · Flood stage
Reference information only. See data sources, editorial standards, or suggest a correction.