Once again about the risk: I do not live on the lower reaches of the Elbe or Danube, but rather in the upper course and at the old water. There has been a canal for 100 years that leads via a reservoir to the power plant. There are also agricultural flood retention areas. In order for the power plant to continue operating during floods and no field to be flooded, the floodwater is diverted into the old water. Here the dam has been reinforced several times and is also maintained, trees are cut down,... Of course, theoretically such a dam could break, leading to HQEXTREM and if nothing is done now and I open the front door, the water would eventually stand 60cm deep in my living room. This will not happen immediately, I am not in the lowest area of the residential area and presumably the water would then be directed back into the canal or/and onto the agricultural flood retention areas. This probably would not please the power plant operators and the farmers. There is also THW and fire brigade which will probably try to repair the dam. In any case, it could also be that in such a case the 60cm is not reached or even nothing happens. This has never happened in the last 70 years since this residential area was established. None of the more than 100 surrounding houses has any flood protection and almost all have a basement.
I am building without a basement, solidly with bricks, concrete and styrofoam and tiles on the floor, so not a wooden/cardboard box. The house was deliberately built a bit higher to be secured against a possible heavy rain risk. Of course, anything can always happen..... I can hardly estimate such damage, but it is probably in the range of €10,000 +/- as the water is not like in disaster movies flooding the house in 2 minutes. I have a natural hazard insurance that covers flood damage (€100/year).
Meanwhile, besides the information from the building authority, I have obtained other information; basically there are three options. Legally everything is vaguely formulated, you should protect yourself, it is not defined what you must do, this was also confirmed by the building authority:
1. Raise the house 80cm: Safest! That would be a completely different house concept than I imagine. I want to build as barrier-free as possible and to be able to enter the garden and the house easily. This is out of the question for me. After consultation, I also significantly underestimated many costs of this concept and the considerable construction delay together could amount to €30,000 and more. Recognized by the insurance.
2. Mobile flood barrier around the house with ground sealing: Very safe, but also about €20,000-30,000. Recognized by the insurance.
3. Mobile flood protection at the house: Depending on the situation, it ideally even prevents the worst, especially if the floodwater does not stand for a long time this system offers good protection. There are several systems here, my preferred one has been certified by TÜV up to 60cm. Recognized by the insurance. €3,000-4,000 I will still get a detailed offer --> Most likely it will be this system. Additionally, I will have the heat pump and fuse box installed a bit higher, luckily power comes from the roof.
After a phone call with the building authority, there is nothing against the mobile system.
But it’s funny what amounts come up when you ask about EXPERIENCES with flood protection systems... you cannot insure yourself against everything with all the money in the world, and when you build a house you have to set priorities and live with risks...
If someone has PERSONAL experience with mobile dam gate systems I would really be grateful