The ground on which the district is located was once covered with water.
The Wolfratshauser See was in no way inferior to the Starnberger See - until it silted up.
Bad Tölz-Wolfratshausen
- The Starnberger See and the Ammersee are famous all over Germany for their beauty and their proximity to the mountains.
What is hardly known, however, is that there was also a Wolfratshauser See, quasi as a third party in the league.
For several thousand years it covered the area of today's district.
However, it silted up a long time ago - a prerequisite for people to be able to settle in the district at all.
Hard to believe, but true: the ground we walk and stand on today was once the bottom of a lake.
The lake plateau in the foothills of the Alps was created at the end of the last ice age, the so-called Würme Ice Age, around 20,000 years ago.
The Isar-Loisach Glacier slowly melted and over the millennia formed several lakes that were constantly changing their shape - including the Wolfratshauser See.
“It was about 150 meters deep,” explains Helmut Schmidmeier (79) from the Geretsried Historical Working Group.
As a retired surveyor, he worked intensively on the lake.
A Geretsried magazine is also being planned.
The mountain forest formed the west bank
According to experts - there is also a Wikipedia article under the term "Wolfratshauser See" - from Kochel, where it was only separated from the Kochelsee by a molasse bar, to the Schäftlarn monastery.
That means: the length of the lake was about 30 kilometers.
It had many islands, shallows and bays.
Achmühle formed the western border, the Peretshofen mountain formed the eastern bank, with a bay as far as Dietramszell.
In general, you can still recognize many relics from the old days.
The mountain forest also formed a border where the glacier water accumulated.
The same applies to the Isar high bank near Hornstein, which drops extremely steeply towards Aumühle.
When the water level fell, a peninsula was created between Schwaigwall and Beuerberg.
“The many moor areas are also a legacy of the lake,” says Helmut Schmidmeier.
Anyone who knows all this begins to see the landscape with different eyes.
+
Helmut Schmidmeier from the Geretsried Historical Working Group
© Hans Lippert / Archive
The fact that the Wolfratshauser See finally silted up after about 5000 years has primarily to do with the Isar.
Its old course first went north over the Kirchsee and the Teufelsgraben.
When the barrier of the Kalvarienberg in Tölz was breached, it found its current path, united with the Loisach and broke through the terminal moraines of the Riss Ice Age near Baierbrunn.
Gravel silted up the lake
The effect was twofold: On the one hand, the river brought a lot of rubble and gravel from the mountains, which slowly filled the lake.
On the other hand, the Isar ate its way north through barriers made of sedimentary rock.
The lake was slowly draining.
The trained eye can still see traces of this today, for example at Ascholding.
There the confluent Isar first formed a flat delta, only to then dig itself back into the heaped gravel.
The steep and high slopes can still be seen today.
Also read: The mountain forest: Wolfratshasuen's life insurance
That the Ammersee and the Starnberger See still exist is only a geological snapshot.
Geological processes take place extremely slowly from a human perspective.
What we take for granted today is not at all.
The Ammersee, for example, will at some point suffer the same fate as the Wolfratshauser See.
“It is gradually being filled in by the bunting,” says Schmidmeier.
Lake Starnberg will have a longer life.
It no longer has an inflow and only a minimal outflow, namely the Würm.
"The Starnberger See now only has about two meters less water than 15,000 years ago."
Also read: That is why the Isar is currently threatened like rarely
No one has ever seen this Wolfratshauser See.
But he has benefited from it by recycling the gravel or the bogs.
A prominent example is also the lake clay, a deposit from the Ice Age, which the calmly flowing Loisach, dammed back by the Isar, washed into the Wolfratshauser See.
In Gelting it was burned into bricks for a long time.
Hence the name "brickworks".
Say someone else that the Ice Age has nothing to do with the present.