Datum Plane

[Pat Mullarkey]

I am looking at a job to provide shore power to a boat dock on the Mississippi river. 555.2 defines the Datum Plane for tidal waters as the normal high tide and the Datum Plane for non-tidal waters as the highest water in the area occurring under normal circumstances. I am interpreting this to mean the highest flood stage, would that be correct?

 

[GoldDigger]

A flood is not a normal circumstance, IMHO.
It would include highest seasonal water level for a lake. Harder to quantify for a river or stream.

When flood level is meant, it should be called out as "10 year" flood, "100 year" flood, etc. to nail it down.

 

[mgookin]

They have what's called flood stage which is the level at which the river flows over the banks and floods the area. Flood stage is not what the electric code is talking about. It's talking about the highest expected normal rise as GoldDigger has said.

As to what that elevation is, I suggest you discuss it with the local electric inspector, if there is one.
Hopefully he and the floodplain manager for the region have some sort of consensus as to what elevation you are expected to build to.

Welcome to the forum.