Current rain in Bavaria does not bring soil recovery - hydrologist fears that it will get worse in the future

Created: 09/26/2022, 11:41 am

By: Anna Lorenz

The past week brought autumn weather to Bavaria, and it will continue to rain in many parts of the Free State in the coming days.

However, the dryness of the soil in the forest and field will hardly defeat it.

Nuremberg – It's raining in large parts of Bavaria, and visitors to the Munich Oktoberfest also have to get used to the wet and cold grey.

The soil, which was severely affected by the heat this summer, is becoming wetter again – but there can be no question of the soil recovering.

Rain in Bavaria: relaxation for the upper layers of the earth - but Nuremberg hydrologist warns against short-sightedness

According to an expert from the German Weather Service (DWD), at least the top 30 centimeters of the ground are filled with water again thanks to the heavy rainfall in recent weeks.

"It's nice that there's finally precipitation," says hydrogeologist Johannes Barth from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU).

Soberingly, however, the moisture penetration of the upper layers of the earth is the proverbial drop in the ocean, because according to Barth, this is "simply not enough to replenish deeper layers of the soil and the groundwater in the long term." The pumping of groundwater by mineral water companies, as is also the case in Bavaria is operated, this problem is intensified.

As the DWD adds, "due to the current weather situation with falling temperatures and additional precipitation", little water would evaporate so that the reserves in the ground could be further replenished.

However, Barth takes a critical view of this, since when it comes to soil moisture penetration, you have to look deeper and consider longer periods of time.

At greater depths, the drought, which attracted public attention in particular due to the extreme heat in summer 2022, is far from over - "and hasn't been for years," says the hydrogeologist.

Nuremberg hydrologist on the dry soil: The "right" rain is particularly important

According to Barth, not only the volume of rain is decisive;

the "right" rain must also fall, said the head of the Chair of Applied Geology.

While a dried-out soil is often not able to absorb individual heavy rains, permanent, light rain would make the soil, which is currently almost water-repellent, receptive.

Dry despite the rain: The floors are currently almost water-repellent.

(Iconic image) © IMAGO / HMB-Media / Heiko Becker

“That means we would need weeks of drizzle or, in winter, finally a snow cover followed by melting.

As a result, the water can penetrate the soil much more efficiently and slowly, and it can also get deeper.” The background: Dry soil can have a water-repellent effect and then not absorb water at all or only very poorly.

Accordingly, continuous light rain would be better to counteract the dry soil - in contrast to individual heavy rain events.

After a hot summer and a rainy autumn: will Bavaria have to adapt to different weather conditions in the future?

According to Barth, the change in weather conditions caused by climate change "can already be seen as a warning".

"Drought and extreme weather conditions are an even more pressing problem this year, for example in large parts of southern Europe," emphasizes the hydrogeologist and recommends preparing for future drier soils.

In the course of this one can learn from other countries - for example Israel.

Among other things, drip irrigation is used very efficiently in agriculture there.

Incidentally, private individuals can consider making their gardens consciously climate-resistant.

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