I'm doing a LOMR application for a client on Lake Martin in Dadeville,AL. Lake Martin in Dadeville is a Zone A which has no BFE's. The subject property is 4' higher than the Alabama Power flood limits due to a retaining wall running around the entire property. Also, lake Martins elevations and the dam has its own datum ( Martin Datum). I have talked with many local officials and agencys and cannot get an answer about the BFE's or any that have been done in the past. I'm kind of spinning my wheels on this one, I've never ran across an situation like this when doing a LOMR. Has anyone ever done one like or similar to this? Anyone have any suggestions or ideas?
What exactly do you mean by "Alabama Power flood limits"? What is happening at the dam and all spillways when this magic number has been reached? Are all spillways open and the emergency spillway at full depth or do you mean top of dam or something significantly lower? Is there any possibility of runoff being so impeded that it could flood the property from above? By this I mean the typical reason for having flood areas in upland situations...the water cannot exit fast enough as opposed to the water merely backing up from a somewhat remote obstacle/constriction.
The high water level is a 490' (Martin Datum) or full pool level. The water level in the summer I believe sits around a 488+- and in the winter is normally around a 478+-
So, when water is flowing at a depth of four feet or more out of the emergency spillway, there will be water on the subject property. What is the maximum flow depth of the emergency spillway?
Don't laugh. It's not the least bit funny when the dam operators have no choice but to let the emergency spillway take all it can take. Everyone downstream for many miles is praying they keep the emergency spillway closed so that your client's place gets damaged instead of all of theirs.
I have witnessed huge trees hung up in the highest branches of other huge trees because the emergency spillway was not allowed to be opened.
I had a similar situation last year in having a property removed from FEMA Zone A on Toledo Bend Reservoir in East Texas. There was no BFE established by FEMA around the lake, so I was able to use the Take Line of the reservoir which was determined to be the high water line (no flowage easement) after proving to FEMA that the Sabine River Authority did have the authority and governmental acceptance to do so. Let me know if you want more info and want to discuss it over the phone tomorrow.
Sounds like some good questions that the attorney of the client
suing you might ask you in court.
Just my anecdotal experience -- FEMA will yield to rules of the
local authorities.
Typically in Houston, Civil Engineers and more specifically, Hydrologists prepare LOMRs. I was not aware surveyors could do this.
I think a surveyor can do it. Refer to the NFIP Requirement and Guidance Documents here:
But the Local Flood ordinance Administrator will be the one you should contact first.