FEMA culvert freeboard requirements
FEMA culvert freeboard requirements
(OP)
FEMA requires 3 feet of freeboard for levees, but is their a freeboard requirement for culverts? A developer wants to build adjacent to a creek that goes underground through a culvert for 50 feet. If, for example, the hydraulic analysis shows the water surface elevation at the upstream end of culvert is at elevation of 100 feet, at what elevation must the finish floors be? This is not a levee situation. The effective map shows this area as an A zone, so we are having the developer do the hydraulic analysis to determine a BFE.





RE: FEMA culvert freeboard requirements
According to FEMA/NFIP the FF has to be at or above BFE (based on FIS flows or similar). That is just the minimum requirement. I don't believe that there is a requirement for culvert freeboard. Most local municipalities (in my area, anyway) enforce stricter measures (i.e. FF anywhere from 1 to 2 feet above fully developed water surface and 1+ foot of freeboard at culverts).
RE: FEMA culvert freeboard requirements
RE: FEMA culvert freeboard requirements
RE: FEMA culvert freeboard requirements
In an unnumbered A zone as you have described, I would believe that requiring the FFE to be 2 feet above the calculated BFE should be sufficient. Before the first shovel full of dirt is turned, the developer will have to have a building permit. To receive a building permit in our region the developer must either have an approved "no-rise" or a CLOMR. A LOMR isn't always the answer.
Robert Billings
www.newrivereng.com