The persistent rainfall of recent months not only causes flooded cellars and meadows. It also leads to subsidence and holes in roads. In Eindhoven and Breda they can discuss it. A large number of sinkholes have emerged there. “Everything depends on how watertight the sewer system is.”
In Breda the counter is at eight and Eindhoven could count on ten holes or subsidence. Due to record amounts of rain, municipalities had to work hard in recent days to repair the countless sinkholes. These are caused by the subsidence of sewer pipes. The pipes often collapse under the weight of all the water they drain.
It is precisely at such a time that the chance of a sinkhole is greatest. Especially with sewer pipes in sandy soil. “There may then be a crack in the connection of two sewer pipes,” says Rien Smalheer. He is a road engineer at the Breda University of Applied Sciences. “If there is such a hole in the sewer pipe, sand also flows into it. That is sand that lies under the asphalt. At a certain point, the subsoil sinks into the sewer. If the top layer of the pavement then collapses, you have a sinkhole.”
“The subsoil sinks into the sewer.”
Residents of Hendrik Staetslaan, Doctor Berlagelaan and Fakkellaan in Eindhoven have recently witnessed such holes. One of the places where things went wrong in this municipality is the intersection of ‘t Hofke and the Oude Urkhovenseweg in Eindhoven. There is a meter deep crater in the road here. This is a result of the heavy rain that has fallen, according to councilor Rik Thijs. “We have sandy soils here and a lot of water in the sewers. That’s how these kinds of gaps arise.”
According to Smalheer, burst water pipes can also be the cause of a sinkhole. He also cites the increase in rainfall due to climate change as an important reason for the problems.
According to the councilor, it will take until February before the hole at the intersection of ‘t Hofke and Oude Urkhovenseweg is repaired. The costs are 300,000 euros. This is reason for the municipality to check all old sewer pipes for vulnerabilities.
Smalheer sees the long-term solution in renewing old sewers. “The lifespan of a sewer is perhaps 100 years. Once it starts breaking down, you can opt for a temporary solution or renewal. Everything depends on how watertight the sewer system is.”
“The lifespan of a sewer is perhaps 100 years.”
The councilor still sees an opportunity to combat the problems. “Another option is to store water more above ground. We will also focus on this in the future,” said the councilor.
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