Locally sourced ‘rock armour’ used on £116m Levenmouth line

Network Rail

WORK is underway on the £116 million Levenmouth rail project to protect the future railway from the impact of the adjacent river.

Network Rail said that the addition of scour protection at a number of locations along the railway will help reduce the impact on the river’s banks from the natural erosion that takes place over time as a result of the continuous movement on the water.

The organisation identified a number of sites in need of reinforcement, with the riverbanks at the locations being stabilised and voids infilled before ‘rock armour’ was positioned to protect the area – this involved positioning large boulders in the river to change its course and stop it from reaching the newly strengthened embankments.

To date, over 2,000 tonnes of locally sourced ‘rock armour’ has been deployed to protect the new railway. Network Rail added that, whilst necessary at specific locations, this is in addition to more natural flood management measures being undertaken along the rail corridor in conjunction with the wider Leven programme.

The natural flood management being considered by the Leven programme includes placing large tree-trunks into the river, modifications to Kirkland and Burn Mill Dams, and naturally re-profiling the banks of the lower Kennoway Burn to improve its connection to the floodplain.

Network Rail said that reinstating the railway adjacent to the River Leven was ‘always going to present challenges’ to the project to find ways to protect the railway from the river – but also to protect the river from any impact during construction work.

One risk to the river from placing rock armour is from silt, it added. The project team were able to use bubble curtains and silt bags to reduce the risk to the aquaculture from the construction work.

Bubble curtains are created by gasses being let out on the riverbed and when they rise they act as a barrier to stop the formation of waves and block the spread of contaminants, including silt and plastics.

Joe Mulvenna, project manager for the Levenmouth rail link project, said, “It’s important that we work with the river and not against it to ensure that the railway is protected from the impact of more frequent and more intense spells of wet weather and the flooding it could cause.

“Strengthening and reinforcing embankments and defending them with the addition of rock armour is one element of our plan to do this but we are working with partners to enable the addition of more natural measures to protect the embankments and to allow the river to work more naturally.

“And while we carry out the work, utilising innovative measures like bubble curtains is just one way we are reducing the risk to the river from the adjacent construction activities.”