The planning for flood protection on the Leitzach in the Fischbachau district of Hammer is progressing.
The water management office is currently examining the draft planning.
This shows where dikes and walls are to be built.
What is particularly exciting is what happens to the bridges: nothing.
Fischbachau
- If there's no room for improvement, then dig down.
This is how - to put it in very simplified terms - according to the current state of planning, the solution for the flood needle eye at the Leitzach Bridge over State Road 2077 in the Fischbachau district of Hammer can be described.
As Hans Heigenhauser from the Rosenheim Water Management Office responsible for the project explains, the originally planned options of raising the bridge or a bypass have now been discarded.
Tests had shown that the cost and benefit were not in an acceptable relationship.
The bottleneck is to be mitigated with a whole package of measures: The bed of the Leitzach will be deepened in the bridge area, and a wild wood screen will be installed further up the river to prevent blockages from driftwood.
"In this way we ensure that the HQ 100 standard is adhered to for the entire flood protection on the Leitzach", explains Heigenhauser.
This is decisive for the approval of the measure by the Free State of Bavaria, which - apart from the municipal contribution of 30 percent - takes on the costs.
But one thing is certain: "Bridges are always a weak point," says the expert.
Upstream there would be three more on the Leitzach: one for an agricultural field path, one for the railroad track and the wooden footbridge.
Only the latter would comply with the latest guidelines, says Heigenhauser.
Since it would not be economically viable to defuse all bridges, compromises have to be made.
In order to protect the residents from flooding, the water management office is planning a combined solution of earthworks for dykes and walls for confined spaces on the corresponding river sections.
Talks with the property owners - including Stadtwerke München, which operates a hydropower plant on the Leitzach in the Hammer area - have already taken place.
It has been agreed with the Fischbachau community that - as soon as the Corona situation allows - the new local council will be informed of the current planning status.
Even if the major project has made further progress, there is no fixed schedule.
There are too many imponderables in the long plan approval process that is due to start in the first quarter of 2022.
Heigenhauser estimates that it could easily take a year for all specialist agencies, nature conservation associations and the public to participate, including a discussion date and weighing up.
Also read: Wolfsee and level crossings: Fischbachau wants to tackle these projects in 2021
Once everything is through and the building is ready, the ball goes back to the community.
They have to take care of any necessary land acquisition and finance their own share.
Heigenhauser is currently unable to make a reliable statement about the amount that could be involved.
First, the draft planning of the engineering office must be checked by the water management office and the government of Upper Bavaria.
“It's running right now,” says Heigenhauser.
All in all, a start of construction before the end of 2023 is not realistic, says the expert.
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The residents of the Aurach, whose flood risk is being dealt with by the community (we reported), would not benefit directly from the measure on the Leitzach, but they would not need to fear any deterioration.
"That", says Heigenhauser, "is a mandatory requirement for every flood protection project."
