Prolonged drought may be worsening damage to Medieval churches in the Netherlands

Medieval churches in Groningen may be suffering deterioration caused by drought on top of the earthquake damage, NOS reports. This was concluded by climate and soil experts in an exploratory study commissioned by the Province of Groningen and Stichting Oude Groninger Kerken.

They examined the effect of drought on the artificial dwelling mounds on which churches stand in Den Ham and Oostum. The study was prompted by damage to an Oostum church back in 2018. Researchers suspect that changes in the underlying soil, potentially linked to prolonged dry conditions, may be contributing to the movement of the buildings. They say such a problem can continue threatening churches in the region.

The church in Oostum, the nave of which dates back approximately 800 years, remains an important part of the local community. Its caretakers, Hesther le Grand and Niels Smit Duyzentkunst, say preserving the building matters because of its historic significance. In recent years, however, cracks have increasingly appeared in the walls, potentially accelerating the building’s deterioration.

“It cannot be taken for granted that the church will still be standing here 800 years from now, because the deterioration is happening very rapidly,” Floris Boogard, a lecturer of Climate Adaptation at Hanze University of Applied Sciences, told NOS. In his opinion, many other churches besides the two examined in the study are experiencing similar issues.

“We looked at the movement of the building itself, as well as that of the dwelling grounds. You can see that the church in Oostum is moving,” he told the news outlet.

“We can see that groundwater levels are falling,” says Boogaard, who mapped the soil conditions. “We know that peat oxidizes and can become more compact. Then there is clay. We took samples of it and analyzed them in the laboratory, and it turns out to be what is known as ’shrink-swell clay.' This means that it expands when water is added, but when drought occurs, the ground subsides.”

Possible protective measures are also being examined. One proposal for Oostum involves digging shallow pits around the church to collect rainwater, allowing it to gradually penetrate the surrounding soil. Maintaining more consistent moisture levels could help limit the expansion and contraction that contribute to ground movement.

“I think it is very good that people are now looking into what is happening and what we can do about it,” Duyzentkunst told the news outlet. “It would be wonderful for the entire community if places like this could continue to exist.”