Geohazards and roads: Norway’s ongoing problem

–Louise Vick

With the news of Norway ‘split in two’ this week from a bridge collapse we are facing the reality, yet again, of a society dependent on road access through mountainous terrain. I discuss why we continue to be surprised by these events, and what we can do to safeguard our roads in the future

Background

For those not following the case, a new bridge along the E6 sustained damage 31st May 2022. The bridge is vital access across a river in Kvænangen, with no alternative route in Norway. Motorists and transporters are having to detour through Finland, while air ambulances are placed on standby. The central bridge pile has sunk into the river bed by c. 1 m, creating a noticeable dip in the bridge rendering it unusable.

I do not have details of the construction and engineering of this new bridge, but my guesstimate would be some sort of subsidence in the river bed, leading to the sinking of the bridge pile. This is reminiscent of the 2010 bridge collapse in Breivikeidet, where liquefaction in the stream bed led to the draining of aquifers in the subsoil, and subsequent collapse of the bridge. Liquefaction is more commonly associated with earthquakes, but can be triggered by other natural and human factors (such as shaking from heavy machinery).

Road closures in Norway are not new news (as it were). For example in 2020, the E6 was closed due to rockfall at Skibotn, rendering the road impassable for a few days. Luckily there was an alternative ferry route, but it caused mass delays and chaotic queues for motorists and travelers.

The larger problem

We as a society in Norway are at constant risk from disruption by the natural environment. The mix of remote communities, mountainous terrain and a lot of surface water from rivers/rain/snowmelt is a recipe for disaster. Every summer we hear new of roads cut off from rockfall (steinsprang) and debris flows (flomskred-jordskred). We are warned of the coming of large rock avalanches (fjellskred). In addition we have flooding, lots and lots of water with heavy supply in spring/early summer and during rain storms. Every year in late May/early June we see big events, such as the quick clay slide near Alta in 2020. Temperatures hit plus degrees almost overnight in the north, triggering large volumes of snow melt water input to the soil. In the case of the quick clay slide, the snow melt event was the largest in c. 60 years- it is only a surprise we didn’t see more landslides!

The truth is, we cannot stop these events from happening. The frequency of them is increasing, partly due to climate change, partly due to increased urbanisation of remote areas. I should also mention, reporting of these events is also increasing.

But why do we continue to be suprised by these events? And what can we do to safegueard our critical access routes against future events?

The solution

It is not an easy, or quick fix. As with everything in life, it comes down to a question of money. In an ideal world, where infrastructure investments were fairly spread across the whole of Norway, and money isn’t a problem, we would do the following things:

1. Have redundancy built into the access routes. By this I mean back-up bridges and road passes at places identified as critical for traffic flow and access. This could mean two sections of highway/tunnel, two bridges, or temporary bridges available for rapid placement (this is a tactic in my home country of New Zealand).
2. Safeguarding existing sections of road. Safeguarding against geohazards can be done with the use of for example: rockfall engineering (e.g. nets and bolts), barriers for landslides and remotely triggered snow avalanche systems. And no expense spared! In addition, ongoing monitoring of risky sections with cameras, radar, water level and weather gauges etc.
3. Education of relevant people for a safer future in Norway. This last point is especially close to my heart, as an educator of geohazards students. Many of my graduates go on to work in the road design and road administration sector. It is important to me that they understand these losses are not to be accepted as part of life, but something preventable with the right understanding and knowledge. Knowledge is power. Imagine a *very much fake* scenario: someone at Fylkes X has to accept or deny a submitted design for a bridge over unstable ground. However, the person at Fylkes X did a geology degree, and they know that unreliable soil sits at 10 m below ground level in this river. They know what the possible consequences are of building a bridge with a pile to 10 m below ground level is. They do not accept the design, and instead require the engineer to design something more relevant. That is all it might take to avoid potential disaster!
4. Heavier investments in expertise. The roading authority had a high number of experts before they were reallocated to the regional counties. I do not want to get into the politics of this, it is way outside of my scope. However i will say that they are a very experienced bunch of people, with a lot of local knowledge about Norwegian terrain and potential disasters. These people should be supported, with more positions, with funding for continual professional development, and with infrastructure for road protection.
5. Investments in climate adaptation. Completing steps 1-4 are really also steps towards climate adaptation. However, we should keep our mind on the coming changes. This is especially true in northern Norway, where climate change is already being felt, and the climate projections are far more extreme. More water, higher temperatures and frequent storms- we must prepare our infrastructure to cope with these. This means the design of new roads and bridges should take into account not just today’s problems, but different problems we expect 20 years from now. Troms and Finnmark County is currently seeking a senior advisor in climate adaptation- this is a great start! Now lets see an increase in the money available to counties and municipalities for adaption of infrastructure- right now the pot of money is a joke.