Coastal Floodplain AE vs Shaded X
Hello All, I have been busy and have not visited in a while. I have a question so here I am hoping for experts to add something.
Coastal Floodplain, Shaded X and AE. Earlier guidance from the powers that be was to hold the mapped line but now there is new guidance stating to hold the contour even if it results in the AE completely overlapping the Shaded X.
In the map below the VE is red, the AE is orange, the Shaded X is blue and the X is not colorful. The AE to the south has a BFE of 15. The road just north of the AE15 has a low point of elevation 14. The big lobe of Shaded X to the north matches the 15′ contour.
If I were to file for a LOMA or an Out as Shown LOMA for any property in the blue, I would expect to get it. However, I am being told by the County Floodplain Manager that the State Guidance is to map the AE to the contour which will mean that several homes located a significant distance from the mapped floodplain will be in the floodplain.
Is anybody seeing the same guidance? It feels like when someone has a subdivision plan in hand but then sells different lots each defined by deed.
- 3 Replies
It is not unusual for local Floodplain Mappers guidance to differ from FEMA. Shaded Zone X is a 0.2% chance of flooding area. Not enough for FEMA to assign a Special Flood Hazard, but enough to be cautious and pay attention. You still need to maintain the Base Flood Elevation from the associated AE Zone, but you do not need to apply for a LOMA since there is no ??hazard?? to be removed. Technically, it is a ??we do not have enough data to determine? of a ??we did not take the time to figure it out? Zone. It is up to the Surveyor and Floodplain Mapper to keep the citizen from building too low.
I always thought that when filing a LOMA you were supposed to hold the surveyed elevation of the flood plain. The FEMA mapping is less precise than what a boots on the ground surveyor can produce. That’s why they have a Letter of Map Amendment in the first place.
@peter-lothian The Out as Shown LOMA requires no survey.
I worked with the former State Level CFM (Rich Zingarelli) on this problem. His take was the the Mapping rules require a certain width to make a second AE zone, so in this case, the AE15 is so small that there is no room to show the AE14 or AE13 where the water would drop as it does with multiple zones in line with each other. His take was to treat the Shaded X like a second AE – where you hold the map and then the contour for the most landward flood zone. It made sense to me and I did not have to tell the dozen property owners on this map that they are actually in the floodplain.
Now we are getting ‘guidance’ from CZM to hold the contour over the Shaded X. I am asking for more than guidance with the expectation that one day I will be grilled by an attorney as to why I followed guidance without following the explicit rules.
In the case of this shaded X, what if you performed a survey at the far extent. You check out the FIRMs and see Shaded X – OK, no problem… oh wait, you now need to verify the elevation all the way back to the AE to confirm? That could be a lot of work that ultimately makes more problems for your client…
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