After extreme rain in Saulgrub: there are reasons for the flooding - now the place should be protected

Created: 12/22/2022, 2:05 p.m

By: Manuela Schauer

Scene of horror: The day after the storm, the water level in the bypass structure drops, and the two flooded vehicles emerge.

The 61-year-old Pole lost his life in the small truck.

© Angelika Warmuth

Short but heavy: The storm at the beginning of May this year brought rain of unforeseen proportions.

An extreme case like this occurs less than once in 100 years.

Saulgrub should be prepared for the future.

Saulgrub

– Horst Hofmann unfolds the first card.

It primarily shows Saulgrub.

Houses, streets, meadows.

And blue areas that mark the path that the Kraggenaubach paved on May 5th of this year.

The area between the commercial area and, above all, the bypass, which it flooded.

The expert from the Water Management Office Weilheim (WWA) picks up the second card.

The blue color dominates in large parts of the place.

Water - it came from all sides.

Moderately.

Detailed information about the storm and its consequences is now available.

It was a tragedy that had taken place that May evening.

In the evening, around 8.45 p.m., a thunderstorm cell discharged over Bad Kohlgrub, Bad Bayersoien and Saulgrub.

Cellars filled up, mud and debris sloshed through parts of the community.

Particularly affected: the B23, especially the valley of the Saulgruber bypass.

It was completely flooded, the water rose between the walls.

"It was more than six meters high," says Hofmann.

All around: a lake landscape.

At the last second, a woman saved herself on the roof of her car, for a man from Poland any help came too late.

The 61-year-old drowned at the deepest point in a pickup truck.

Horst Hofmann shows the map with the floods caused by the Kraggenaubach alone.

© Shivers

The great guesswork began after the devastating storm.

Rumors of defects in the structure or a malfunction of the traffic light, which indicated that it was closed, circulated.

It is now clear that none of this led to the accident.

According to the Munich II public prosecutor, a death investigation had been initiated.

However, there was no preliminary investigation because there was "no evidence of third-party negligence in the fatal accident".

In particular, according to public prosecutor Christian Steinweg, "according to the expert assessment, the system or underpass in question was correctly designed".

No flaws, no defects.

The red light was also active and clearly visible.

Rain events of this type are extremely rare

Nature showed its ghastly side.

According to the data available to the WWA, more than 70 liters of rain per square meter fell in an hour and a half.

This means that such an event occurs on average less than once every 100 years for the Saulgrub/Bad Bayersoien site.

"At this level of persistence," explains Hofmann, "it can therefore be described as extremely heavy precipitation."

In order to gain clarity as to why and how these massive floods came about, the WWA commissioned the engineering office Kokai.

This recorded local evidence, questioned witnesses, evaluated videos, measured the culverts and calculated the event using the rain data.

It was simulated hydraulically on the computer, says Hofmann, who is responsible for flood protection in the district at the Weilheim authority.

The Kraggenaubach with its winding route was one of the main reasons.

The passage at the Seiler nursery, which was severely affected by the storm, "didn't make it," says the expert.

The pipe next to the B 23, on the other hand, is relatively large and, given its cross-section, should have been able to cope with the masses.

The catch: the water was already backing up on the other side.

However, the brook alone cannot be blamed entirely.

The large amount of wild water that flowed from Saulgrub's hillside made the situation much worse.

Both factors led to the bottleneck, the point where the railway line and the B 23 cross, being flooded.

The water slopped over the walls of the building into the depression.

"The bathtub," as Hofmann describes it strikingly, "filled up from the outside."

The water masses overwhelmed the pipe of the Kraggenaubach.

© Fellner

The WWA employee vehemently contradicts allegations that the local bypass was insufficiently designed.

He also makes it clear that neither technical failure nor even bad drainage facilities would have caused the drama.

They weren't designed for such a "disaster fallout," he concedes.

Building in the necessary dimensions would be impossible.

Just looking at the pipes.

"You can't pay for that anymore," emphasizes Hofmann.

"Somewhere there are limits."

also read

Bargain hunt in the swimming pool: community sells Wellenberg inventory

READ

15,000 euros collected in 36 hours: Upper Bavarian starts appeal for donations for a sick dog

READ

New folk festival host in Murnau: top dog Fahrenschon loses a territory

READ

On the road with summer tires: Brite lands with Volvo in the Degernlaine

READ

Karwendelbahn is now serving beer: A brewery opening with a question mark

READ

Fancy a voyage of discovery?

My space

You have to take action.

Horst Hofmann from the WWA

At that time, before the start of construction, there had been plans for a diversion between the garden center and the B 23, which would have led along the road.

They didn't get a chance.

Failed due to nature conservation and property owners, Hofmann recalls.

Could the horror scenario have been prevented?

He shakes his head.

The road would probably have been affected anyway, says the expert.

The past has been dealt with, now the WWA is looking to the future.

Because Hofmann is certain: the heavy rain events, such as those recently seen in Hammersbach, in Grafenaschau or in Garmisch-Partenkirchen am Ferchenbach, are not decreasing.

Climate change is noticeable.

"You have to take action," he says.

The municipality itself has taken the first steps.

For example, ditches cleared and blockages removed, says Saulgrub's mayor Rupert Speer.

According to him, the Weilheim State Building Authority is planning work on the groundwater basin at the beginning of 2023.

Different variants are discussed

Overall, the precautions are divided into three areas.

This includes what is known as flash flood risk management.

The WWA has advised every municipality to create such a concept.

In this context, the wild run-off water is examined.

"It's very important," the mayor said.

The municipality is responsible for making the call for tenders and submitting the funding applications.

Another point: the event documentation.

The WWA caused it.

Number three on the to-do list: working out a flood protection concept.

The authority is thus in the preliminary design phase.

Kokai developed variants.

Models with dam and drain, with stormwater retention basin, with pipe.

A consultation was held on Monday.

It is important to weigh up which solution is the most sensible and economical.

"We're at the very beginning," says Hofmann.

Discussions with authorities, the community and, if necessary, property owners are still pending.

Speer, who attends the meetings, would logically appreciate it if it were possible to intercept and divert the water outside of town.

The time will tell.

And of these, he predicts, a few more will elapse before implementation.