But the garage in zone ae would. Start by walking them through the well defined and simple cases.
From the Flood Plain Study that was done. That I doubt is accurate to a tenth of a foot.
The BFE has varied from over 9 feet over the house floor as estimated by FEMA to ,4 foot resulting from the Flood Plain Study.
I've asked the Engineering Firm that did the Study for an accuracy estimate. If they come up with one I expect it will be more ammunition for my argument.
Maybe the county agency is just PO??d that neither of the buildings had the proper permit in hand when they built the structures. Isn??t it on the owner of the structure or the owners contractor depending on their contract to have all proper permits before any work is done??ÿ
@skeeter1996?ÿ ?ÿ Pretty much disagree with everything you said, based on geometry, my experience, NGS vs OPUS, FIRM maps and working with local officials. OPUS order of error does not relate to the height different you will find on the ground. One day OPUS will be within a tenth, the next day OPUS will be two feet out. Do not use OPUS for benchmarks or you will continually run into the the same problem you just had.
A similar situation happened locally. The NGVD29 elevation maps were replaced with NAVD88 maps. One community seemed to have had the conversion reversed leaving the NAVD 88 maps 2.5 feet lower instead of 2.5 feet higher. That meant that you could build almost into the water of the river. In that community every new subdivision/house plan needs it's own study.?ÿ
I suspect that your log house is not in the flood plain and getting on the study that was done will fix the issue. You really have to at this point, whatever elevation basis they used to determine their BFE you have to get on also.?ÿ
@oldpacer?ÿ Correct. That is my experience.
The Flood Plain Study should be accurate only at the cross-sections shown.?ÿ Everything in between those is an interpolation that may not be correct.?ÿ That's better than no help at all.?ÿ Generally speaking,?ÿ Zone A is a SWAG until it is checked out to the level that it becomes a Zone AE.
For now, we contact the State Division of Water Resources for a magic number to use in a Zone A that they are arriving at based on LIDAR information taken during recent flooding.?ÿ This tends to give higher numbers than what will eventually turn out to be one percent occurrence elevations.?ÿ It is what we must use, however, as FEMA won't advise anything lower until they complete the next update and publish it for the FIRM.?ÿ Again, this is better than no help at all.
Following FEMA FIRM updates I have seen specific areas added to the flood plain and other specific areas removed from the flood plain.?ÿ But, as mentioned elsewhere, I have witnessed with my own eyes, flooding to even higher elevations.
I pretty much tell everyone who is wanting an elevation certificate in hopes of getting a LOMA approved that they, collectively, are a bunch of dumbasses when it comes to all new construction.?ÿ For existing structures, it will at least get their insurance rates set correctly for the time being.
In the Summer of 1979 I ran soil compaction tests daily for a site that was being raised as much as 29 feet in order to get the floor of the lowest level of the motel being built to a height precisely one foot higher than the City Building Code requirement to be one foot above the one percent flood level.?ÿ In 1986 a major flood occurred which resulted in the lower level rooms being flooded to within an inch or two of the ceiling.?ÿ They were reconstructed for continued use.?ÿ I believe that has now happened at least three times but with slightly lower water levels.?ÿ You can still rent a room there if you choose to do so.
Benchmarks? What stinkin' benchmarks. Ninety five percent of the areas I work in have zero benchmarks and if there happens to be one, it's a 29 from the 50s and has no published NAVD88 elevation and hasn't been monitored. I've checked over a dozen in my region doing F1A letters and they're all garbage. To get a NAVD88, I have no choice but to rely on CORS, whether I process it myself or through OPUS. For that very reason I wouldn't touch an elevation certificate with a 10' pole around here. Why any surveyor would take on that liability without a reliable way to verify their work is just beyond me.?ÿ
Just because I'm paranoid, doesn't mean they aren't out to get me.
@skeeter1996?ÿ ?ÿOnce again, I disagree with everything you just said. FIRM Maps ARE based on NAVD 88, just like it says on the FIRM Map. They are not based on Ortho Heights derived from a Geoid. Apples and Oranges. The photogrammetry IS precise, the Flood Zone boundaries ARE NOT intended to be a contour line. They will go from 12 feet to 24 feet in a heartbeat, That is why LOMA'S are so easy to get. FEMA is a government organization, just like the Post Office, SSA and IRS. DO NOT except common sense rules or you will fight Elevation Certificate preparation the rest of you life. Learn their rules and go with the flow. I have found FEMA Flood elevations to be very accurate, you are just measure the wrong place with the wrong ruler.
And where might the right ruler be that fits their data? I'm discovering there isn't one.
That's a possibility, but I'm not a trained psychologist to figure that out. They have to back their feelings with facts and I'm saying .4 feet isn't emought.
@skeeter1996?ÿ ?ÿ How has FEMA tried to deceive you? How is FEMA (not FEMA contractors) but FEMA, incompetent??ÿ Have you ever talked to a FEMA specialist, they are extremely knowledgeable about their role in the process and WILL help you negotiate their poorly designed system. Who have you dealt with at FEMA that is stupid??ÿ If you told me that I am incompetent, I would not like you either, no wonder you don't get what you want from the bureaucracy.
?ÿ
@skeeter1996?ÿ ?ÿYou don't understand why the county does not want an unpermitted building below BFE on the books. That seriously handicaps their Community Rating Service number, causing flood insurance in the area to cost more. A FEMA audit is one of the most fear event a public servant can have.
@bill93?ÿ I have had to do that once in my life. Everyone gets called in during a storm, provided a box of 60D nails, a handheld GPS and a rental car. Instructions were to dive around an area and drive nail at high water or high debris, get a coordinate and add it to a form. Do not know if elevations were ever obtained or not.
@skeeter1996?ÿ ?ÿPerhaps you do not understand the difference between a Plane and a Geoid?
Simultaneous observations are certainly the gold standard...but we should also consider that an OPUS solution is exactly that (usually far away), right? Is it not the case that each CORS in the NGS network is a benchmark all on its own?
?ÿ
The issue is the distance from the CORS, at least around here.
Around here, if you were 3.5 feet off, I would assume the datum was screwed up, but not all NGS benchmarks are equal in the first place.
?ÿ
@bill93?ÿ
And this is the critical point...the benchmark(s) used to establish the BFE is the only relevant one.
I don't think we should waste our time with me defending myself from your kind of accusations. I'm not sure how to block you, but so far your input has not been useful.
Sorry