Questions concerning the A9 Kincraig to Dalraddy dual carriageway: EIR release

Information requested

I would like to request the following information with regards to the A9 Kincraig to Dalraddy upgrade:

a) Was the ditching, in which heavy duty plastics are used as a material, included as part of the construction contract and specified as built?
b) Was the use of heavy duty plastics for ditching signed off by Transport Scotland?
c) How much heavy duty plastics were used as part of the ditching works (miles and width)?
d) What is the total distance of ditching along this section which use heavy duty plastics?
e) What is the expected lifetime of the heavy duty plastics?

Response

As the information you have requested is ‘environmental information’ for the purposes of the Environmental Information (Scotland) Regulations 2004 (EIRs), we are required to deal with your request under those Regulations. We are applying the exemption at section 39(2) of the Freedom of Information (Scotland) Act 2002 (FOISA), so that we do not also have to deal with your request under FOISA.

This exemption is subject to the ‘public interest test’. Therefore, taking account of all the circumstances of this case, we have considered if the public interest in disclosing the information outweighs the public interest in applying the exemption. We have found that, on balance, the public interest lies in favour of upholding the exemption, because there is no public interest in dealing with the same request under two different regimes. This is essentially a technical point and has no material effect on the outcome of your request.

a) Was the ditching, in which heavy duty plastics are used as a material, included as part of the construction contract and specified as built?
The purpose of the ditch is to prevent runoff from the adjacent land from running down the earthwork slopes. The purpose of the plastic is to provide a continuous impermeable liner to prevent the ingress of water from the ditch into the slopes. The overall aim being to prevent water entering the slopes, which could lead to destabilisation of the earthworks.

The requirement for ditching is dictated by design standards. The Contract states that where ditches are to be provided, they are to be lined with an impermeable liner. The lining material used is not specified but was selected by the Contractor to meet the requirements of the design standards and the Contract.

b) was the use of heavy duty plastics for ditching signed off by Transport Scotland?
Transport Scotland does not sign off elements of the design. The Contractor is responsible for the design and construction, including the selection of lining material to meet the requirements of the design standards and the Contract.

c) How much heavy duty plastics were used as part of the ditching works (miles and width)?
Approximately 2,100m (1.3 miles) of liner was installed as part of the project. The width of liner used varies from 2.5m to 1.5m at depending on the location.

d) What is the total distance of ditching along this section which use heavy duty plastics?
Over the 7.5km (4.66 mile) of dual carriageway that was constructed as part of this project, the length of lined ditches constructed was approximately 1,050m (0.65 miles) on each carriageway giving a total length of 2,100m (1.3 miles) for the project.

e) What is the expected lifetime of the heavy duty plastics?
The design life of the ditch liner is a minimum of 120 years.

About FOI

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