FEMA Flood Zones

[mpallamary]

Does anyone know under what authority a Land Surveyor can plot FEMA flood zones on an ALTA survey or any other mapping document when surveyors are not licensed as hydrologists?

Thanks!

[Warren Smith]

SMA 66434.2 for subdivision maps, if required by local ordinance.
ALTA surveys with proper attribution.

[mpallamary]

Thanks!

So tracing a FEMA flood zone is acceptable? Do you concur?

[Warren Smith]

I would say so, being that FIRM documents are public records, and if the origin is cited.

[Ian Wilson]

But NOT showing earthquake faults on such maps. That would be the practice of Geology!

OOUCH!

I think I broke a tooth shoving my tongue in my cheek on that one.

[mpallamary]

Made my day

[mpallamary]

I ran this by Gary Kent, the master of ALTA standards and he says it is fine, of course, if one is tracing such things. I have been unable to find any rules or laws that prohibit Land Surveyors from tracing others maps and reports, as long as they cite the basis for the document.

[LS_8750]

The floodplain delineations are approximations based on often times bad data to begin with. Garbage in garbage out.

Couple scenarios:
1. Elevations are given on FIRM - then you go off that firm and topo along that BFE contour line until you find it; or
2. Floodplain or Floodway limits are shown on the FIRM and you are retracing the line from the datasets, probably because you do not have an elevation. Interestingly, the datasets are supplied in State Plane coordinates so that limits engineers per 8726. But, typically the elevation data is not supplied because the quality of the FIRM data is not good.

In either case you are wading through some sludgy waters and can expect to find all sorts of errors on the FIRM. But sometimes the FIRM data is pretty good.

[CBarrett]

I worked for a Geotech Engineer for about 3 years, before recession, on 3D modeling and data collection and data plotting methods, and volume calcs etc. The likelihood of a land surveyor plotting a fault line in a correct position based on Geotech feedback is a lot higher than if the geotechnical engineer or their techs do it themselves.