Wasserbetriebe test new method for groundwater recharge

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  The drainage trench is 25 meters long.

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  Before the water reaches the groundwater, it is purified.

Berliner Wasserbetriebe is testing a new method of groundwater recharge to ensure that water continues to flow reliably from our taps in the future.

A so-called seepage slot trench more than seven meters deep has been installed on a Berliner Wasserbetriebe site in Johannisthal. The idea: collected rainwater or river water, for example from the Havel, is fed into the trench. The water is purified beforehand. The water then seeps away via the slot and reaches the groundwater.

New technology requires less space

The aim is to stabilize the water levels in Berlin, as the head of the water supply, Gesche Grützmacher, explained at a press event. Groundwater recharge in itself is not new. However, according to Wasserbetriebe, large rectangular basins were previously common in Berlin, for example at the Tegel or Spandau waterworks. The advantage of the slotted trenches is that they require less space, said Grützmacher. The new technology is now being tested before it is possibly used.

Berlin's drinking water is stored from groundwater

Groundwater is used for our drinking water from the tap, for irrigating fields or watering animals. Berlin's drinking water comes from groundwater reserves beneath the city. According to Wasserbetriebe, the groundwater is constantly being replenished by rainfall and surface water. This happens mainly in the fall and winter.

Sewer system does not flow into the groundwater

However, in particularly densely populated cities such as Berlin, it is sometimes difficult for water to reach the ground. If the rainwater flows into the sewage system, it is lost for groundwater recharge. In some areas where the groundwater cannot recharge sufficiently, the water companies therefore supply it with pre-purified water from rivers and lakes. For this purpose, it is dammed up in shallow earth basins or in ponds and ditches.

Water consumption currently low

Due to the summer vacations, less water is currently being used in Berlin than usual, said Grützmacher. Consumption had also been significantly lower recently due to the rainy July. When it rains, no additional watering of plants is necessary. In some cases, only as much water was used in one day as is normally used on an average autumn or winter day.