Natural solutions to secure Nordics against ravages of extreme weather
The extreme weather event Storm Hans was an example of the possible consequences of climate change for critical infrastructure such as roads and railway lines. A Nordic research project offers solutions on how to prevent such destruction in the future.
Kjersti Gisnås from the Norwegian Geotechnical Institute is leading the NordForsk-funded societal security project NordicLink. They’ve been researching how the Nordic countries can best protect their linear infrastructure – roads, railways, and energy supply lines – from climate-related natural events. These events can include landslides, avalanches, and not least flooding, as seen with Storm Hans.
“The events following Storm Hans constitute one of the most expensive natural disasters we’ve ever had in Norway. It serves as a prime example of events that may become more common due to climate change, and that’s precisely what we’ve been addressing in NordicLink,” she explains.
The research project involves participants from Finland, Sweden, and Norway and has conducted case studies in four different areas of the Nordic region: Savo in Finland and Eidsvoll, Trollstigen, and Gudbrandsdalen in Norway. When Storm Hans struck, the Gudbrandsdalen case study suddenly became very relevant.
“One of the hardest-hit areas was Gudbrandsdalen, which we’d used as a study area several years before Storm Hans hit. Roads and railways were closed, with the railway suffering severe damage. The Norwegian Public Roads Administration estimates that the reconstruction costs in Gudbrandsdalen alone will amount to at least NOK 50 million. In the project, although we conducted analyses on the potential costs of road flooding, we underestimated them. Towards the end of this century, we expect to see a fivefold increase in the annual cost of damage to the road network due to extreme weather.”
Nordic co-operation project
Kjersti Gisnås points out the advantages of Nordic collaboration on the project:
“We face many shared challenges in Norway, Sweden, and Finland, and much of our infrastructure is interconnected. Co-operation is incredibly valuable. Our countries share a similar climate, and although our populations aren’t huge, we have vast land areas that make it difficult and expensive to protect ourselves against extreme weather.”
The project’s researchers have also benefited greatly from working with external partners such as the Swedish Transport Administration in Sweden, as well as Bane NOR and the Norwegian Public Roads Administration in Norway. All agree on the importance of preventing and protecting critical infrastructure against floods and landslides caused by increasing amounts of precipitation,” says Kjersti.
“Storm Hans served as an eye-opener because it demonstrated how severe the consequences can be when extreme weather hits vulnerable areas. This has been high on the agenda of infrastructure managers for several years, and they’ve undertaken many preventative measures. However, protecting ourselves from events like Storm Hans is a challenge, and one which we expect to become more frequent in the future. They’re calling for more knowledge, both in terms of identifying future risk hotspots and sustainable solutions to prevent them. It’s far less expensive to prevent and secure areas than to rebuild them after extreme weather destruction. However, infrastructure managers need various solutions to be demonstrated to them, as well as guidance on how to implement them. That’s where our research project comes into play, as we’ve tried to fill that knowledge gap.”
The researchers have worked on three main themes. Firstly, they’ve looked at how to better identify the areas that are most vulnerable to natural hazards in the future climate. This is essential for prioritising where to secure first. When it comes to prevention, there is currently a strong emphasis on choosing sustainable solutions. That’s why the project has developed methodologies for monitoring and warning of imminent landslides on individual slopes. Work has also been done to obtain more knowledge about choosing nature-based security solutions. This involves implementing preventative measures with positive environmental effects to reduce the risk of landslides and floods.
Nature-based solutions can involve working with the area’s natural features, restoring or maintaining vegetation to limit flooding, and managing vegetation on mountain slopes to stabilise them and prevent potential landslides. Instead of installing downspouts and building embankments and dams, which the researchers refer to as “grey measures”, nature can be utilised to secure vulnerable areas. In some places, “grey measures” will still be required for sufficient risk reduction, but combining them with nature-based solutions can reduce the overall impact.
Nature-based solutions are a top priority elsewhere in Europe, with significant resources allocated to urban areas, including activities like reopening streams, green roofs, and reestablishing vegetation. However, in the Nordics, not as many resources have been dedicated to preventing floods or landslides in steep terrain, as Kjersti explains.
“After Storm Hans, it became evident that there are extensive areas which need to be protected. So it’s impractical if we don’t consider more sustainable solutions instead of primarily implementing ‘grey measures’. This is a desire shared by all our partners, but they need more knowledge about the impact and implementation of these measures. Although it’s not necessarily more expensive to implement nature-based solutions, the planning can be more extensive," she says and adds:
"There’s less experience, and it can be more challenging to calculate the impact of these measures. When you build a dam, it needs to be large enough so that landslides can’t go over it. This can’t be done with nature-based solutions. On the other hand, it’s entirely unrealistic and less sustainable to protect all infrastructure by way of ‘grey measures’ when we have so much exposed infrastructure due to the elongated shape of the Nordic countries.”