Landslides triggered by Storm Desmond at the A83, Rest and Be Thankful, Scotland

Storm Desmond produced intense and prolonged rainfall which resulted in extensive flooding in the U.K. A number of landslides were also triggered, many of which damaged infrastructure and the transport network in particular. We are in a unique position, holding pre-event, and during event data for slopes that failed during and after Storm Desmond (Figs. 1, 2) at the most 'at risk' trunk road in Scotland1-3, the A83 Rest and Be Thankful (RABT), Argyll and Bute, which is a key arterial route. Since 2007 at least 13 debris flows have occurred, with road closures causing annual estimated losses of £286,300 to the local economy1-3. Existing monitoring (Fig. 1) has been invaluable in defining post-event conditions and sediment dynamics with instruments often installed after events, but there are no complete (pre- and post-) data on a single large event. This is essential in refining and validating physical and numerical modelling approaches, which can be used for enhanced management of the problem, and the design/refinement of appropriate monitoring and mitigation strategies that our project partners are responsible for putting into operation. Our proposal is to collect transient post-event data to allow follow-on funding proposals to answer the outstanding science questions, which are relevant for multiple sites beyond the RABT, and to document the transience of key evidence to inform how 'urgently' we do need respond to future large events to adequately quantify them.

We have identified two groups of beneficiaries, the first of whom have direct operational management of the landslide problems at the A83 Rest and Be Thankful (RABT), the second group are the 'at risk' population, threatened directly by landslides when using the road, but also affected by road closures.

A83 Operational Stakeholders
Transport Scotland who have overall responsibility for the road network, and BEAR who are the operating company are named Project Partners, with one of the science objectives being feedback of our Urgent data collection products so that they can feed into operational management of the slope. We will undertake a site visit, and office visit with/to both, along with other stakeholders: Maccaferi Geotechnical (who have designed a number of the debris flow flexible barriers), and NavStar (also a Project Partner) who design bespoke monitoring/warning installations that can be commanded/controlled remotely. We will also run a stakeholder workshop. The deliverable from this workshop will be an assessment of the current monitoring / warning provision and a range of cost-benefit scenarios of future mitigation and monitoring solutions for the RABT, as one of many trunk road sites at risk from landslides.

A83 'At risk' Population
We wish to focus our impact activities on a particular subgroup - school children. We will produce a 'debris flow in a drainpipe' physical model as a classroom activity for the secondary schools in the vulnerability shadow, tailored to fit the new A-level and Scottish Highers Geography curriculum. In the first instance PI Dunning, and Co-I Lim, along with 4 final year undergraduate students (undertaking, or having completed classroom placements pre-PGCE application) will run the activity to pass the knowledge on to School teachers. The models allow for elements of project design, data collection and analyses, basic statistics, through to much deeper conceptual understandings of 'risk'. These experiments reinforce the STEM nature of Physical Geography, and the roles of Geographers, Geologists and Engineers in managing our natural environment.