Is the normal pool elevation on the navigation charts published by the Corps. based on vertical datum of 1929? The charts state they're based on NGVD (no date). I would assume 1929. Have a call into the corps but thought I would pose the question here.
Most any BM used to determine any relaltive elevations at COE waterways should be what is used to determine water level and overflow grade of that waterway.
That is what the Pool elevations are based upon.
You can report any difference in the final report as how that elevation relates to current obtainable information.
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When was the dam built? Here the corps lake elevations are related to whatever was used to build the dam.
That's probably the best assumption.
Remember that almost all have flowage easements which are based on recorded legal descriptions. Those are going to be based on the spillway elevations at the time the dam was built. I'd assume 1929 datum but you can always contact the district's survey branch and ask.
Isn't 1929 the only NGVD?
Along the Ohio River, many are listed as NGVD but are actually ORD (Ohio River Datum). It's normally about 0.6' different than '29, in an opposite direction than '88.