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The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.
Loyal readers may remember that in January of this year I posted a piece about the ongoing scandal associated with the Nordic Waste landslide in Denmark. In brief, this was a large failure in a landfill run by a company called Nordic Waste that was threatening to both pollute the local watercourses and to damage infrastructure. A key element of the scandal was that the operating company was placed into administration, leaving the Danish taxpayer with the costs of the remediation.
There is a really remarkable Google Earth image of this landslide, captured on 17 March 2024. I have included the lat/long in the image:-
A new, open access, paper (Svennevig et al. 2024) has now been published in the journal Landslides that describes the results of the investigation of the failure. This is a really excellent piece of work -I thoroughly recommend a read of it. I cannot do justice to the full range of the investigation here, so will focus on a fairly narrow element, the cause of the landslide (which ultimately determines who was to blame). This is important as Nordic Waste blamed climate change for the landslide – Denmark had been experiencing a particularly wet period when the landslide sprang to prominence.
Dumping of waste soil into the old clay pit started in 2016. Using archive imagery, Svennevig et al. (2024) have been able to show that instability initiated in 2021. The rate of movement accelerated in 2023 – the accumulated displacement of a road across the landslide reached 20 metres, and a part of a building in the facility had to be demolished.
From April 2023 through to the end of the year, the pattern of dumping of waste soil changed, with the primary locations moved to the upper, western part of the pit, rather than in the central part of the facility. In response, two earthflows were formed (these are clearly evident in the Google Earth image above), which then moved down to the main portion of the landslide, which in turn accelerated further. Svennevig et al. (2024) recorded movement rates of up to 9 metres per day in January 2024.
Unbelievably, soil dumping continued right through to 6 December 2023, but on 19 December, Nordic Waste abandoned the site. Movement continued through the early part of January 2024, but ceased three weeks after the end of the dumping of soil.
As noted above, the key question at this site is the cause of the landslide. Runout modelling shows that it moved with a low friction angle – just 2.9°. Svennevig et al. (2024) highlight that movement stopped soon after the cessation of the dumping of soil, but at a time when groundwater levels were high, and still rising (they eventually peaked two months later). In addition, movement was initiated in 2021, and continued through 2022, which were comparatively dry years.
Thus, there can be little doubt that this was not a landslide associated with climate change, but instead resulted from the dumping of waste soil.
The Nordic Waste landslide is an amazing case study of a large-scale, anthropogenic slope failure. This highly credible paper provides a wonderful overview of the events, and their causes. I’m left amazed that Nordic Waste could continue their operations through 2022 and 2023, when large-scale movement was clearly evident, and that included changing their dumping operations in a manner that accelerated movement. And then, on top of that, they abandoned the site and declared the company bankrupt, leaving the public sector to deal with the aftermath and the cost.
In an article published in October, DR.dk reported that the final bill for the issues at the Nordic Waste site is likely to be about US$70 million, shared between the state and Randers Municipality. Claims have been made against both Nordic Waste and the landowner, DSH Recycling. The latter is now suing Randers Municipality, so the outcome will be determined in the courts. However, this paper is not going to help the case of the landowner.
Reference
Svennevig, K., Keiding, M., Jackson, S.P. et al. 2024. An unnatural disaster—the 2021–2024 landslide at Nordic Waste, Denmark. Landslides. https://doi.org/10.1007/s10346-024-02394-7
Text © 2023. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.
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