Annex 1 - BEAR Scotland Presentation

Slide 1 - Introduction

  • A83 Taskforce
  • Meeting No. 25
  • 24 January 2024
  • Ged Mitchell
  • Design Manager
  • BEAR NW

Slide 2 - Presentation overview

  • Ongoing hillside monitoring regime
  • October 23 landslides – A83 RabTh & Glen Kinglas
  • Planned improvements – A83 Glen Kinglas
  • Emergency works – A83 Aray Bridge
  • Forestry and Land Scotland works
  • Wider A83 / A82 works programme

Slide 3 - Hillside Monitoring Regime

Slide 3 as described in text below. Scientific chart showing magnitude of movement in a landslide site since it was last monitored.
Slide 3

Daily management of the route is continuing behind the scenes, to ensure it is safe for road users. This includes:

Daily

  • Remote weather station monitoring
  • Expert weather forecasting
  • Ground saturation estimates
  • Remote timelapse photography
  • Daily decision-making on use of A83 or OMR

2 Weekly (depending on weather, more frequently)

  • Site team observations on hillside condition and watercourse flows
  • Hillside movement surveys and observations.

Slide 4 - October 2023 Landslides – A83 RabTh

A83 Traffic diverted onto Old Military Road on Friday 6 October following a review of weather forecast and hillside saturation levels, which indicated potential for landslides at RabTh.

The catch pits and fences stopped around 2,500 tonnes of debris and ensured that only a small amount reached the road at the RabTh.

Slide 5 - Temporary Traffic Lights – A83 RabTh

Slide 5 as described in text below. Two images showing a bulge in the road surface.
Slide 5
  • Carriageway defect identified on Monday 22nd January adjacent to October 23 landslip
  • Potentially residual issue from landslip e.g. water ingress.
  • A83 currently under Temporary Traffic Lights
  • Investigation and remedial works to be carried out when conditions permit

Slide 6 - October 2023 Landslides - A83 Glen Kinglas

Overview of landslides that reached the A83 and the four categories they fell into: Open hillside failure. Open hillside failure becoming channelised debris flow. Flow caught by existing protection measures. Location of existing protection measures (bunds).
Slide 6

Overview of landslides that reached the A83

Slide 7 - October 2023 Landslides - A83 Glen Kinglas

Slide 7 as described in text below. Image of A83 cleared of debris, while evidence of the landslide can be seen either side of the road.
Slide 7
  • 12,000 tonnes of debris cleared from the Trunk Road
  • Seven landslides impacted the road, with the A83/A815 junction to the west end of Glen Kinglas badly affected
  • Rainfall totals of 160mm in a 36-hour period
  • Teams worked tirelessly in challenging conditions to reopen the A83 to all traffic
  • A83 reopened after 5 days

Slide 8 - October 2023 Landslides - A83 Glen Kinglas

Caption: October 2023 landslides - A83 Glen Kinglas. A selection of images showing the extent of the landslides.
Slide 8

Slide 9 - October 2023 Landslides - A83 Glen Kinglas

Caption: October 2023 landslides - A83 Glen Kinglas. Image of diggers on the scene as part of the clean-up response.
Slide 9

Slide 10 - October 2023 Landslides - resilience of wider Argyll & Bute area

  • Local Resilience Partnership was activated on 7 October
  • Series of multi-agency meetings held on 7 October and then daily during following week.
  • Meetings chaired by Police Scotland and attended by a wide range of partners e.g.:
    • Transport Scotland,
    • BEAR Scotland,
    • Argyll and Bute Council,
    • National Health Service,
    • emergency services, and
    • other transport mode partners.
    • These meetings were crucial for (i) disseminating information relating to the numerous (simultaneous) emergency events across the region, (ii) raising awareness of the capability of partners to assist, and (iii) coordinating mutual aid and communications.

Slide 11 - Planned Improvements – A83 Glen Kinglas

Slide 11, as described in text below. Includes image of workmen inspecting ditch on A83.
Slide 11
  • 150m of temporary concrete safety barrier to be installed at A83 Kinglas in late Feb / early March 2024 (slip 8)
  • Barrier will help prevent further material from slope reaching the road
  • Existing ditch being deepened and widened
  • Culverts being cleaned out to increase drainage capacity at this location

Slide 12 - Emergency Works – A83 Aray Bridge

  • Phase 1: immediate protection works, backfilling a scoured area at the bridge apron and installing steel sheet piles to protect against further scour
    • Works currently ongoing
  • Phase 2: permanent repair and replacement of the stone pitched apron under the full structure and permanent repair of the apron
    • Work will start in early 2024 when appropriate design work is complete and environmental licenses are in place

Slide 13 - Current Works – Tree Planting – Forestry and Land Scotland

Slide 13 as described in text below. Map showing the locations of tree-planting phases.
Slide 13
    • Phases 1 and 2 complete
    • Phase 3 is ongoing and due to be completed by Sept-Oct 2024
    • Phase 4 to be completed by May-June 2025

Slide 14 - Wider A83 / A82 (South) Programme

  • Total A83 investment since October Taskforce ~ £2.31M
    • £2.91M of further A83 investment planned for remainder of 2023/24 FY
  • Total A82 (Tyndrum to Balloch) investment since October Taskforce ~ £330K
    • £110K of further A82 investment planned for remainder of 2023/24 FY

Slide 15

Thank you and any questions