Water supply in the Rhein-Sieg district Ice-cold drinking water from the pipes
Rhein-Sieg-Kreis · Drinking water coming out of the pipes is currently ice-cold. But according to the Wahnbachtalsperrenverband, there is little danger of the pipes freezing over and suddenly not a drop of water flowing out of the tap.
Before the thaw set in on Monday morning, temperatures had been in the minus range for days. This caused the ground to freeze. As a result, the drinking water coming out of the pipes is currently icy cold. Is there even a danger that the pipes will freeze and no more water will reach the households? A concern that Dirk Radermacher, deputy managing director of the Wahnbachtalsperrenverband (WTV), can allay: "The water pipes are at a depth of 1.20 metres and the frost won't reach there." For that to happen, there would have to be much longer cold spells with even lower temperatures.
In addition, the WTV network has very large dimensioned pipes and the water is in constant motion. "Our pipes are 30 centimetres to even a metre wide in some cases," he says. In addition, the water always has a certain basic temperature: "We take a large part of the water from our dam and the four-degree cold water is layered in it due to the higher density at the bottom," he explains. At this temperature, water has the highest density and is therefore the heaviest.
"When the water gets colder, it becomes lighter and eventually even changes its state of aggregation as a floating layer of ice," Radermacher explains. For drinking water treatment, the heavy water, which is around four degrees warm, is taken from the bottom of the dam. When it finally comes out of the taps of the approximately 800,000 people in Bonn, the Rhine-Sieg district and parts of Rhineland-Palatinate who are supplied with drinking water by the WTV, a glass of water can easily have a temperature of six to seven degrees on icy days, estimates the deputy WTV managing director. Theoretically, a lowest temperature of four degrees is conceivable.
However, WTV only delivers its water to distributors such as cities, municipalities or public utilities. A lot of water has to be transported up to the delivery point, and from then on the network tapers off because the demand becomes smaller and smaller, says Radermacher. The diameter of the water pipes is also getting smaller: "Especially in urban areas, the pipes to the individual households may only be between eight and ten centimetres wide," he says. Less wide pipes would freeze more quickly. But even they are usually at least 1.20 metres underground.
Possibly a danger with old pipes
"Of course, there are still old pipes that are perhaps not so deep and where the danger of frost could possibly exist," the WTV deputy managing director admits. Or if a pipe has not been laid properly, as could be the case with some consumer pipes in the garden, there is also the danger that they could freeze over. "There is no one-hundred-percent certainty, but in my 25 years here I have never seen anything freeze up in the WTV distribution network," he says.
(Original text: Scarlet Schmitz; Translation: Mareike Graepel)
