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Question:

Preface - I am NOT building in the flood plain. Is the burden of proof on the county to prove i'm not complying with the rules? What is the worst to happen if I simply build a 100% flood plain compliant house and stop providing surveys and additional maps proving i'm not in the flood plain?

County Rules:

No permit to build county, no cert of occupancy etc., drain-field permit only (already have). Permits required (by state) + engineering if inside the flood plain.

Details:

Below is a snapshot from the 1980s fema maps which shows the Base Flood Elevation Break-line in red at 3195 feet above sea level, running East-West. 1/3 mile to the south of that line, is a 3196 breakline (not pictured). The blue area is determination of the floodplain from 1980 air footage and said to be "on average 95% accurate". The red square is where I wish to build. The mobile home pictured is gone / I removed it. There is a functioning drainfield behind it which we have permission to use from the sanitarian (only permit actually required).

The flood plain administrator and building official in my county seem to be making up some rules or at least be over-cautious (or i'm just confused).

They requested I provide a detailed survey proving that FEMA is actually accurate "because 1980s photos at 30k ft aren't 100%". So, I provided a detailed survey (to the 1ft contour) which shows basically what you would expect below with some areas where I want to build all 100% between 3195 and 3196. Now they are claiming that's fine if I build above the 3195 break-line because that guarantees that 3195 contours, north of the 3195 break-line are above base flood elevation. The issue is, if I want to build south of the 3195 breakline (as pictured), the base flood elevation is likely 3195 + maybe an inch or two at most (based on the distance to the 3196 contour. They want a base flood determination done in this area even though my contour map shows it at or above 3195 and some of it even at 3196 and 97.

enter image description here

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    What does your insurance company and mortgage lender have to say on the question? – Harper - Reinstate Monica Jun 12 at 16:13
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    Given the number of houses built on what geographers called flood plains that then got flooded and the owners now cannot understand why they cannot get insurance you might eventually find out why they are asking for detail... – Solar Mike Jun 12 at 16:16
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    Will they be satisfied if you build the house on stilts? Spend the money on raising the house rather than fighting them. – Mattman944 Jun 12 at 16:22
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    I'll just add that I had a similar experience with my own property and obtaining a building permit. The determination of flood-plain is not based on elevation (as you might expect) but on proximity. The COE just draws lines at a certain distance from a body of water. I had to prove that I was not in a flood plain and that took a survey and a lawyer to prepare the documents. In fact I'm nearly 50' above the 100 year flood elevation but you'd never know that from a 2D map. – jwh20 Jun 12 at 16:47
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    It's not an inch or two, it's like 1/16" over 1/4 mile with 1' rise. Can you just show them stamped architect drawings that show you will grade the pad one foot higher (to 3196 + 1/16"), That would put you above both lines. Will they accept electronic elevation app data, rather than expensive surveys? Can you back the building away from the contour line a bit, to throw them a bone? – Jimmy Fix-it Jun 12 at 18:02
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Since in commentary you've stated that you're already committed to genuine flood-resistant construction, now it's just a matter of documenting that to the satisfaction of insurance companies and the county.

My advice is to research the gold standards in flood-immune construction, and modulate your design so that it plainly conforms to that. I don't think you need to go to the extreme of stilts; it just needs to meet whatever standard they will be satisfied with.

The new designs being used in the Gulf Coast are just basically stilts but in the form of continuous poured concrete walls. Flood remediation is one of those scrub-brushes you attach a hose to, and down the drain/out the door it goes.

As far as insurance, just because you're cash-building this one, doesn't mean you can afford to cash-build its replacement (A flood may not ruin it, but fire would). Also, insurability means resale value, and even if you don't see it, your heirs will.

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    Thanks! Updated my question to clarify hopefully. You bring up good points. A secondary but important goal here is to avoid the requirement for flood insurance. In my experience from selling a flood plain compliant home in a 100 year, you devalue the home a solid 20%-30%. Not because people are concerned with flooding, but because a large portion of their monthly income goes towards flood insurance (required) when instead it could go towards more house. ie. Most people only buy flood insurance if required because it's not cheap and it's mostly worthless - doesn't cover much. – maplemale Jun 12 at 17:46
  • @maplemale Would it help to regrade the property so the house is 5' higher than it is now? Mind you, you could set the foundation on terra firma, then regrade after. Sorta like the way they build underpass bridges on the ground, then hollow out under them... but in reverse :) – Harper - Reinstate Monica Jun 12 at 19:39
  • @harper-reinstate-monica You would think - yes. The problem is I am not allowed to modify a flood plain in any way without a permit and impact study etc. ie. re-grading is modifying. If I was a little less honest, I would have brought in material last year, planted grass and then ordered the survey. But to your point, i'm absolutely going to do that outside the flood plain (assuming I can prove I am). It's just smart in this scenario where I'm on a big flat, high groundwater area. – maplemale Jun 12 at 20:08
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This has been resolved / worked out with the county. This is not an exact answer and no one else provided one to the question: Was the county pushing their authority beyond it's limits? But it is at least a list of facts I learned:

Facts - Things I learned:

  1. The County Flood Plain Admin was "concerned" that if I build in this location, while it is outside the flood plain boundary, it could very easily change and will likely change "as FEMA does it's updates in the next 4-5 years". Also, the detail of the contours isn't enough to prove those maps are 100% accurate. Now, 20 years ago I remodeled a house next to the flood plain boundary and updated it to be flood proof 100% at the urging of a different county flood plain admin who stated "FEMA map revision to occur in the next 4-5 years". So, i've been hearing this tale of FEMA map updates for 20 years now and it hasn't happened yet. Hm...

  2. At the county's urging or demands (not sure what they really were) I hired a surveyor to do a BFE (base flood elevation) determination at the site. Which showed me, a few inches below in areas. While I could have raised the dirt and leveled these areas + built a flood proof home, it would mean the county would require lots of permits and inspections at a significant overall cost increase and time delay. vs moving the house slightly - which is what we did.

  3. We moved the house slightly to the south, outside the floodplain based on the higher detail map provided by the surveyor and we are approved by the county at this point - but we will of course build a 100% flood proof house as we always planned to do. No one will require flood insurance. If FEMA were to move the boundary and change the definition of the BFE (increasing it above 3195 at that breakline), we would be grandfathered and could file a LOMA (Letter of Map Amendment) which I'm told would be approved for 2 reasons: Because we will be raising the dirt significantly (without a permit cause it's not in the floodplain) and based on the work we just did to prove we are outside the flood plain. Thus, no insurance would ever be required, even for subsequent owners.

Some what-if facts:

  1. If I didn't ask for permission, i would have built the ground up outside the current definition of the flood plain map per FEMA. The County would have to prove I did that in an elevation that was below the flood plain before I started, which is difficult (but not impossible?) to prove.

  2. If I built in the original location proposed, and got a mortgage, the flood plain determination done by the mortgage company would absolutely show me outside the flood plain because it is based on the map pictured in my OP.

Remaining Question:

Could the county have done anything about me building in this location without their explicit permission? I have no idea - but I'm sensing no.

Did I over-comply, making it difficult for well intended people after me? Again, i don't know. I feel like better safe than sorry, but I also feel this is a massive overreach by my county. Their constant claim is they are the FEMA umbrella but I don't know that I buy it.

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