Lots of questions, finally answers: The public information event on the planned flood protection on the Amper was long, rich in detail, in some cases emotional - but also necessary.
Because the residents concerned had many questions to which they - at least in most cases - finally got answers on Tuesday evening in the Thomahaus.
Dachau
- “Really dramatic and horrific” is what recently happened to the flood victims in Rhineland-Palatinate and North Rhine-Westphalia, emphasized Mayor Florian Hartmann to around 100 visitors to the information event on the planned flood protection measures on the Amper in the Thomahaus. The topic is "unfortunately very topical", it is now important to "absolutely prevent such things in Dachau".
Constanze Hecker, Head of Planning and Construction at the Water Management Office (WWA) in Munich, her colleague Carsten Esser and Knud Kramer from the EDR planning office now want to do just that.
Or they even have to: "The flood protection plans are anchored in law and uniformly measured to the degree of protection of a 100-year flood event," as Esser explained to the audience.
You cannot protect yourself against a 1000-year or extreme flood, but this event is also included in the planning.
the initial situation
In a flood situation, according to the hydraulic calculations of the WWA, the water at the Gündinger weir overflows its banks and runs in a westerly direction to Dachau.
The water then floods the areas of Im Lus and the wood garden settlement and flows back into the Amper below the Dachau weir.
The aim of the WWA and the EDR engineers is now to divert the water so that it no longer flows back into the Amper below, but above the Dachau reservoir.
In doing so, people, the environment and the national budget are to be spared.
To achieve this, there are two variants, of which - in short - one would be very expensive and the other very damaging to riparian forests.
And a third, equally unfavorable compromise variant "does not solve all problems", as WWA man Esser admitted (see box).
Werner Wolf, Chairman of the Free Gymnastics Association in Munich, which affects an area of 30,000 square meters in Lus, asked the basic question against this background: "Why do we need the whole thing?" the water couldn't overflow?
Wall at the Amper brings nothing
Esser ruled that out, however, as the Amper would "get out of hand" with a ten-year flood.
A corresponding wall would turn the Amper there into an uncontrollable river.
A reservoir or a retention basin, such as the Sylvenstein reservoir, could of course “cut the top in Günding, but we simply don't have that option there”.
Yvonne Schneider was one of those visitors who would have wished for “a concept” in the sense of a holistic solution for the Amper.
Their logic: if you intervene at several points in the course of the river, you don't need the one big measure in Dachau.
Constanze Hecker admitted that this concept certainly works for rivers like Danube and Günz, but not for the Amper.
Their characteristics are completely different.
An intervention on the Ammersee, which is already a "buffer" for the water coming from the mountains, has no effect on Dachau because there are simply a lot of inflows.
The Amper simply has a "very elongated flood wave".
City and Free State share costs
Bernhard Hirsch and Thomas Fuß questioned the “evaluation matrix of costs and ecology” presented by Esser. "I haven't heard anything about human life so far," scolded Fuß, who runs a farm in Lus and fears that he will soon become "uninsurable". Hirsch, who lives in the Holzgartensiedlung, criticized the fact that the Bavarian Ministry of the Environment was obviously involved in the choice of options: "There is a lot of politics behind it," he noted.
Furthermore, that was the message of the evening, the process is literally in flux, which means: It has still not been decided which flood protection variant should be implemented.
The process, which was also confirmed by the Dachau building authority manager Moritz Reinhold, is likely to take many years due to the large number of people affected and the associated high likelihood of legal action.
There are three variants for the planned flood protection on the Amper.
The city and state share the costs for this.
Which variant the water management office endorses is to be decided this year, after which the city council has the last word.
Mayor Florian Hartmann has already announced that “as a city we naturally have to look at the money”.
It is clear to all those involved that this should be irrelevant to any flood disasters. Mayor Hartmann shrugged: "It doesn't get any faster in this country."