Inconspicuous columns on the roadside in Bad Godesberg What's behind the green pillars

Bad Godesberg/ Bonn · At first glance, they appear inconspicuous. It's not easy to work out what's the story with them. There is no imprint, no indication on the almost two-metre-high green pillars that stand here and there in the public street space: for example in the villa district or in the green strip between Gotenstrasse and Wurzerstrasse.

 This pillar towers in the villa district of Bad Godesberg.

This pillar towers in the villa district of Bad Godesberg.

Foto: Richard Bongartz

Local amateur historian Werner Eich has nevertheless noticed them. He suspects that the pillars are quite old. Could they perhaps be a means of communication from the imperial era? He heard this assumption during a guided tour of Bad Godesberg with Rainer Selmann. He had heard the theory from another gentleman who once walked through the neighbourhood with him.

Selmann can imagine that they might be police call pillars that stood in "posh neighbourhoods" in the 19th/20th century. "He also discovered some in the musicians' quarter in Bonn," says Selmann. Historian Norbert Schlossmacher is also perplexed; he says that it is "unlikely" that they belong to the imperial era. And if you look closely, you can also see fairly standard screws holding everything together. There is also a padlock so that not just anyone can open the box.

Many of the boxes belong to the city of Bonn

In the end, the city, which owns many of the green boxes, sheds light on the matter. "These are groundwater measuring points (GWM)," said the press office in response to a GA enquiry. The Lower Environmental Authority in the Office for the Environment and Urban Greenery is responsible for this. However, not all GWMs are assigned to the city. The operators of the measuring points are mainly waterworks, companies, associations and the state of NRW.

This is why the keys for the devices hang in the town hall. They can be used to monitor the groundwater level and how it changes over time. The experts can also determine whether groundwater is contaminated or polluted. This is particularly important if the subsoil in an area is contaminated with pollutants.

Particular care is taken with such things in the case of industry, such as power stations. In technical jargon, this refers to geothermal plants authorised under water law, which must regularly provide data on temperature and water levels, according to the administration. But even in urban areas, people want to know what is going on underground, which is why they have the columns.

The samples are sent to the laboratory for analysis. In addition to the chemical content, the groundwater level is also analysed. The water from below should be so clean that it can be upgraded and used as drinking water.

The last 20

Incidentally, the columns discovered by Eich date back to the 1960s and 1970s. "There are only 20 of them left," says the city: including at the Ernst-Moritz-Arndt-Gymnasium, at the subway in Poppelsdorf and at Beethovenplatz. "These will have to be replaced with modern measuring points next year," says a spokesperson. The rest consist of far more modern devices. There are 1064 in total, spread across the whole city.

Original text: Carla Moreno

Translation: Mareike Graepel

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