Feedback on project corridor options
We are asking for comments on the 11 options by Friday 30 October.
The feedback received will inform the progression of Stage 1 data collection, assessment of corridors and sifting work and we will provide an update on that work as it progresses.
We will then look to make recommendations for a preferred route corridor with alignment options in Spring 2021.
The section of the A83 between Ardgartan and the Rest and Be Thankful car park has a history of hillside instability, in particular on the slopes above the Rest and Be Thankful.
The Rest and Be Thankful is the highest point on the A83, separating Glen Kinglas from Glen Croe. It is also one of the places in Scotland with the highest risk of landslides and debris flow hazards. These have increased in recent years due to the frequency of heavy, intense and prolonged periods of rainfall.
Following a number of landslides in 2004, Transport Scotland carried out the Scottish Road Network Landslides Study. As part of this study a hazard assessment and ranking exercise was carried out for debris flow. From this assessment the A83 Ardgartan to Rest and Be Thankful is one of the most highly ranked debris flow hazard sites in Scotland.
As part of the £82 million invested in the maintenance of the A83 since 2007, over £13.6 million has been invested in landslide mitigation works at the Rest and Be Thankful. This was to help keep Argyll open for business by reducing the impact of landslides on the A83.
We are aware of the A83's importance as the primary route to Argyll. In 2012, the A83 Route Study was carried out to identify and assess potential options to minimise the effects of road closures.
Our objectives then were to:
- reduce the impact on journey times by reducing the frequency and duration of road closures caused by landslides
- reduce the economic impact to the A83 study area by reducing the frequency and duration of road closures.
The resulting landslide measures have seen the opening of the alternative military road, installation of nets, catchpits and improvements to drainage at this location. These interventions have already proven to be successful, helping to keep the A83 open for an estimated 48 days when it would otherwise have been closed.
We continue to explore ways to reduce the risk of impacts caused from landslides in the area.
Construction of the next roadside catchpit at the Rest and Be Thankful, a project valued at £1.2 million, is currently scheduled to be built between this September and March 2021. Once complete, the Phase 1 catchpit will provide an additional 4,600 tonnes of volume to collect debris flow from landslides, to add to the 15,000 tonnes provided in the existing four catchpits.
We have also progressed the programme to proactively plant trees on the hillside to help reduce the risk of landslides in the area. Land purchase at the Rest and Be Thankful has completed and we are working closely with Forestry & Land Scotland to reintroduce the required local provenance native vegetation on the hillside.