Innovative and sustainable engineering solutions developed by BakerHicks, the multi-disciplinary design and engineering company, will protect the foundations of a major highway in Cumberland from future erosion damage that risked undermining the carriageway. As well as safeguarding the infrastructure of the A5086, which connects Egremont and Cockermouth, the project has also created a new habitat to allow wildlife and plants to thrive.
A 15% increase in rainfall in the region over the last ten years has resulted in changes to the alignment of the adjacent watercourse. This meant a section of the main road and its associated infrastructure at Scallow Farm was starting to be compromised. To address this, Cumberland Council appointed BakerHicks, through their Professional Services Framework, as the Designer, to realign the watercourse and strengthen the highway embankment.
Ground investigation surveys were undertaken to confirm the existing ground conditions and identify the key design parameters to create a robust and more stable highway embankment. In addition, ecological assessments, including the Preliminary Ecology Assessment and Habitat Regulations Assessment, were carried out to ensure environmental considerations were fully integrated into the design.
BakerHicks used 3D modelling to realign the watercourse, ensuring it worked with the local environment constraints, as well as carrying out open-channel flow analysis to assess the stream’s capacity and using ‘Hjulstrom Curves’ to evaluate and reinforce the watercourse beds.
The new watercourse design prioritises flood prevention and enhanced environmental benefits, reducing its whole life embodied carbon by over 5%, according to BakerHicks’ in-house carbon assessment and measurement tool, CarboniCa.
To achieve this, natural features like ponds, marshes, and gentle slopes were introduced to help manage water flow, slowing it by 40% and, consequently, reducing the risk of flooding. The stream’s natural shape was restored with winding paths and strategically placed boulders, along with specially designed ‘dragon’s teeth’ stones, which create small waterfalls and cascades. These additions not only control water movement but also support fish migration, helping the ecosystem thrive.
As Nick Wood, Associate Director at BakerHicks and project lead, explains: “While the primary focus was to ensure the stability of the road for many years to come, realigning the watercourse gave us the perfect opportunity to introduce additional sustainable benefits into the area. This included promoting habitat creation, watercourse geomorphology, marsh areas doubling up as attenuation, and specifying locally sourced materials, especially for the pebble beach areas which attract specific types of nesting birds.”
BakerHicks also supported the Council in drafting the tender documents to appoint the main contractor, Cumbria-based Metcalfe Civil Engineering. They detailed the scope of the work to be undertaken and designed a series of drainage improvements for the road, including several additional gullies and drainage outfalls.
A representative from Cumberland Council, says they have worked closely with BakerHicks, and all contractors involved, to develop and deliver a thoroughly considered and effective solution for these essential works: “Due to the sensitivity of adjusting the watercourse, we needed to deliver a solution that addressed all areas in a timely manner.
“BakerHicks’ attention to detail has been to the highest standard. This collaboration has ensured a safer, more resilient highway for thousands of road users while fostering a vibrant natural habitat that supports local wildlife and promotes biodiversity.”
