Talking about the weather is a tried and tested means of harmless small talk without great potential for escalation. This year, however, most people should be somewhat annoyed when asked about the weather. Although autumn is somewhat forgiving, summer has almost completely fallen into the water. But the weeks of continuous rain do not put everyone in a bad mood.
“It’s already very good for the groundwater this year,” says Thilo Kopmann. He is the managing director of Supply and Disposal Munich East (Vemo). The municipal company supplies around 79,500 tapping points in the districts of Ebersberg and Munich, so between 11,000 and 12,000 cubic meters of drinking water flow through the pipes every day. This comes from the large groundwater aquifer that flows north from the southwest of the district. In the past few years the water level of the underground river has slowly but surely decreased – this year the level is rising again.
“You can tell that it is filling up,” says Karl Seebauer from the Baldham Water Association, which supplies more than 1,700 households in the south-eastern part of the municipality. The replenishment is also necessary, because the deficit of 2020 has to be made up again. Last summer was one of the less rainy days in recent years, as the groundwater levels show. The groundwater begins at a depth of between 18 and 22 meters in Baldham. Only once in the past decade, in the winter of 2004/2005, the water level fell further. Last year the level was just slightly higher, but overall the statistics for 2020 show the second lowest groundwater level since 1999.
In a quarterly comparison – that is fully billed by the end of June – the level is currently around 30 centimeters above that of the previous year and with an upward trend. Even if you can definitely only say it at the end of the year, Seebauer expects that 2021 will be “a pretty good year” for groundwater. Such a situation can also be observed in Ebersberg, according to Franz Schlosser from the district town’s water supply, the levels this year are a good half a meter above those of the previous year. Similar values in the centimeter range are also recorded in the well of the Vemo, says Kopmann – which sounds little at first, but if you consider the size of the reservoir as a whole, it results in enormous amounts of water.
To speak of a relaxation of the development that has been observed for several years, according to which the groundwater level is falling slightly in the entire region, is probably too much, said Kopmann. But at least for the upper layers, from which the drinking water comes, the permanently humid weather is ideal this year. Because brief heavy rain followed by weeks of drought are almost useless for groundwater formation, since most of the water evaporates before it can seep into deeper layers.
Seebauer expects the rainy summer 2021, at least in Baldham, not to reach the groundwater record. Because at the beginning of the last decade there were a few years with high groundwater levels of around 18 meters. The reservoirs were particularly well filled in 2002, says Seebauer, “that was the super rainy summer”.
In the very deep groundwater layers, from 200 meters and further below, you don’t notice anything, says Kopmann. It would take a few years for the water to get there. In any case, these deep reservoirs are of no importance for the procurement of drinking water, neither Vemo nor any other water supplier in the region operates a corresponding deep well.
According to all the water suppliers surveyed, pollutants that could be washed in by the heavy rain are not a problem. For example, manure from the fields, which increases the nitrate value of the drinking water. On the one hand, the groundwater is so deep that a lot is filtered anyway, says Seebauer, on the other hand, Baldham is also in a good location: The wells are in the forest, so that, for example, manure residues from fields would not be flushed into their catchment area.
This location advantage is also available in the district town: “The water protection area of the city of Ebersberg is located in the Ebersberg Forest so that we have no problems with pollutants such as manure from fields,” says Schlosser. This also applies to the Vemo fountain near Zorneding, which is also located in a wooded area. According to Kopmann, this leads to a generally slightly higher nitrate content than in a catchment area under the green meadow, due to the rotting biomass of the forest – leaves, needles or branches. But there is also no entry from agriculture.