How to build in flood zone HQ100 EXTREM

I agree with everyone that with the elevation there is of course 100% protection; for me, it’s not just about the additional 10,000€, everyone who builds knows how quickly 10k€ can evaporate. The house would then no longer fit the terrain and wouldn’t blend into the surrounding buildings; maybe I would even lose the building permit because of that, I am building according to §34 and I have to fit into the surrounding buildings. A huge wall around the property probably wouldn’t be allowed either. With such significant changes, the construction would also be seriously delayed, as the neighbors would probably have to be re-consulted, no surface water may flow onto neighboring properties, and if I fill up so massively, the neighbors would definitely suffer from flooding. I have already raised the level slightly to be protected against heavy rain events.

But as I said, I don’t like a house concept with an exposed house on the property and stairs down to the garden, costs aside. And there has never been a flood, but the dam has been reinforced multiple times. And if this HQ100 EXTREM were to happen, the water would stand 60cm high in the living room when I open the front door; if not, water might seep in here and there.

Are things like dam barriers really pseudo-measures? In Cologne or Salzburg, they have been successfully protecting the old town with them for years. But I haven’t seen them used at a house yet; they are sold in countless variants.

The house no longer fits the terrain and no longer integrates into the surrounding buildings, maybe that’s why I would even lose the building permit, I’m building according to §34 and there I have to integrate into the surrounding buildings.

That’s really annoying. What does the architect say? With this problem, a flood zone is public and known, you would plan for that, wouldn’t you?! You wouldn’t have to puff up your cheeks now if everything were planned in the draft.

Now I spoke on the phone with the responsible lady about whether I can build a wall around my property, that would probably be an option. She said she didn’t know if such high walls are allowed there and I would also have to think about the driveway, she would recommend building 81cm higher, if necessary 61cm higher would work. But I had the feeling that she didn’t know much.

I think she knows what she’s talking about: after all, she immediately argued with the driveway, which you hadn’t considered. She doesn’t have to worry about costs and contingencies.

Raising it would also cost €10,000, I could pay insurance for 100 years with that

There is probably no question now about mentioning insurance. It should be used for unforeseeable events and accidents. That is a collective.
It could also be that the fine print doesn’t cover something like that if you knowingly build differently.

As one can read, you cannot be convinced of such a measure, which to me indicates that you have already weighed it many times and have basically already come to the decision. No one can tell you what will happen; we all only suspect something about the future, and you would now build a house that you no longer like (I would never do that). Since you have thought it through enough, I would also build it like that. My old house was on the Neckar, but in the 4th row on the slope, and the water never reached there. In the first year, the row got it, and all the construction pits or basements + partly ground floors were full. After that, some even had a boat hanging on the house wall. You have such a clear opinion, which I can understand; I would do it that way, and if the worst case once occurs, then just deal with it. In our residential area, the possibility of flooding was always a topic, so people were rather relaxed about it. Better the risk of having water in the basement once in a while than to have to look at and live in an "ugly" house for a lifetime. So I can understand you.

And if this HQ100 EXTREM were there, then the water would be 60cm high in the living room when I open the front door, if not, it might maybe push in here and there.

Since you apparently do not want to believe it, once again very slowly and for you to write down: At small streams that quickly overflow locally during heavy rain and where the flood is gone again after a maximum of three hours, something like this is absolutely effective. With multi-day mixtures of heating oil- and mud-saturated Danube broth, either heavy artillery is needed or you just leave it and limit yourself to the minimal cosmetics that appease the building authority. A little tip, chat with those innkeepers in Passau who are regularly flooded by the Danube every few years. They certainly know their stuff.

City of Regensburg has mobile flood barriers that apparently work surprisingly well. But they are not given for free...

Just take a look at the websites of your responsible water management authority or the State Office for Environmental Protection in Bavaria (keyword: flood). Is your building site located in the HQ100 area or in the HQ Extreme area?