Sylvenstein reservoir: There is still water left for six weeks

The level of the Sylvenstein reservoir is currently falling by around 15 centimeters every day - and for the time being there is no rain in sight.

Nevertheless, there is still a lot of water left at the reservoir.

Lenggries - 15 centimeters - that's how much the water level of the Sylvenstein reservoir is currently sinking every day.

The visible shoreline is slowly getting wider and wider.

The level is now almost three and a half meters below the normal summer level of 750 meters above sea level.

Trend: further falling.

By the way: Everything from the region is now also available in our regular Bad Tölz newsletter.

“According to the forecast for the next three weeks, it will remain very dry.

But we also notice that the temperatures are no longer so extreme," says Andrea Kröner, operations officer for the Sylvensteinsee at the Weilheim Water Management Office.

The authority is monitoring the situation, but so far there is no cause for concern.

Ultimately, the Sylvenstein does exactly the job it was built for in the 1950s, says Kröner: it ensures that the Isar always has enough water through continuous, well-dosed delivery.

The fact that the storage tank can also protect against flooding in an emergency is a welcome additional benefit.

Sylvensteinsee: Only 40 percent of the low water reserve has been used up

Despite the ever-widening banks, there is still a lot of water in the lake.

“So far we have used 40 percent of our low water reserve.

But that also means: 60 percent are still left,” says Kröner.

Converted into days, this means that the water in the reservoir will last for almost six weeks.

Currently, only around 7.3 cubic meters per second flow into the lake

Even after that, the reservoir is of course not completely empty.

But from a storage height of 736.4 meters, the water management office is no longer bound to release enough water for the agreed amounts of water to reach the Isar in Bad Tölz and Munich.

It would then be conceivable that only what enters the lake through the tributaries is released.

This is currently around 7.3 cubic meters per second, and almost double that is delivered to the Isar.

In Bad Tölz, not quite the agreed minimum quantity is currently arriving in the Isar

It is actually agreed that at least 20 cubic meters per second must flow through Bad Tölz.

This is important so that the power plant on the Isar reservoir can generate electricity.

"Since 2011, however, there has been an agreement with the district office that we can deviate somewhat from this water law decision in extreme circumstances," says Kröner.

In fact, only 18 cubic meters per second are currently flowing through the spa town, because efforts are being made to manage the Sylvenstein as far-sightedly and as volume-saving as possible.

This also includes the fact that talks are now being held with the Walchensee power plant operator Uniper.

This is where you can help ensure that there is a sufficient inflow from the Loisach to the Isar.

"We coordinate here," says Kröner.

For the Tölz power plant, the lower amount is not a problem due to turbine damage

Incidentally, the slightly lower amount is not a problem at the Tölz power plant: After damage, only one turbine is running there at the moment anyway.

"If more water were currently coming from the Sylvenstein, this amount would have to flow over the weir unused because of the turbine damage," says Martina Geisberger, spokeswoman for the public utility company ."

Even with the Isar in Munich, everything is still in the green

At the moment, more than 50 cubic meters per second are arriving in Munich, "we still have room for that," says Kröner.

"But of course that could look different in two and a half weeks." It has to be at least 40 cubic meters so that, for example, the waste incineration plant or the heating plant of the city of Munich can function or the elephants in the Hellabrunn Zoo can bathe.

The last time there was a comparable situation was in 2018

"The last time there was a comparable situation was in 2018," says Kröner.

Back then, too, a hot, dry August meant that the Sylvenstein reservoir had to do a lot.

In the end, the lake level dropped by only 4.5 meters due to forward-looking management.

Is the lowering of the lake level in summer still appropriate?

Since the dry periods are apparently getting longer, one could think about not generally lowering the lake level by two meters in summer.

This has only been done since 2006 - as a result of the August flood of 2005 and out of the consideration of having more storage space.

"This discussion comes up with every dry phase," says Kröner.

Of course you look at it.

"But it must also be said that we have so far managed all low water phases without any problems."

The worst drought was in the winter of 1962/63

Incidentally, the worst drought in recent decades was not in a summer, but in the winter of 1962/63.

The low water reserve of 40 million cubic meters was already used up in mid-October.

The reservoir remained at the lowest possible water level for around half a year - and the Isar flowed not even half as much water as specified by the notification.

In 2015, the remains of Alt-Fall emerged from the mud

The lake level then dropped to 739 meters in 2015 – at that time, however, on purpose.

This was necessary in order to be able to work on the bottom outlet tunnel.

The few remains of the village of Alt-Fall, which had to give way for the construction of the reservoir, emerged from the mud.

The foundation walls became a tourist attraction for a few weeks.

You can find more current news from the region around Bad Tölz at Merkur.de/Bad Tölz.