Dealing with challenging ground in a sensitive habitat.

Working on behalf of Scottish and Southern Electricity Networks, Balfour Beatty Power Transmission and Distribution’s near completed newbuild overhead transmission line running across the west coast of Scotland encountered very challenging ground conditions at a number of protected locations. 

The project’s scale and location were challenging factors. Aside from the topography and unprecedented weather, the works also had to account for Special Sites of Scientific Interest (SSSI), Special Areas of Conservation (SAC), sensitive habitats (including peat bog, moorland, farmland and watercourses, private water supplies) and a number of protected species including golden eagle, hen harrier, and red-throated diver.

Preventing pollution

Their pollution prevention programs protected the local ecosystems throughout the project. Particular care was given to silt and particulates from the large borrow pits so they would not interfere with the hydrology of aquatic systems.

As the area spanned a section of one of the wettest areas of Scotland, during a period of intensive rainfall, the Scottish regulator (SEPA) was approached to permit the use of flocculant on the site to help treat silty water. Balfour Beatty sought a variation to their construction site license to protect the local water environment, including the specification of Frog Environmental products. 

Effective products which prevent pollution

Our technical team supplied treated coir mats (Floc Mats™) to support their water treatment and silt pollution preventative aims.

Trapping up to 50kg of silt per mat, our unique and environmentally-friendly Floc Mats™ provide a safe, cheap, and easy solution to support the removal of pollutants from the water. They come in untreated or treated forms, with treated versions having a highly effective, non-toxic gel flocculant impregnated into the natural fibres to aid their silt binding performance.

The 2x1x0.1m Floc Mats were deployed in areas that were difficult to reach with their existing, traditional water treatment plant. Locations included:

• within Silt Capture Channels
• in roadside ditches along access tracks
• in combination with silt fencing
• within natural dispersion fields
• in combination with dewatering bags and silt socks.

“The key takeaway from this project is that it is possible to manage silt pollution to a very high standard with minimal incidents, even across huge scales, varying ground conditions and extreme weather.

“The Floc Mats proved to be a game changer providing innovative silt management. We are now using them on another overhead line project and look forward to the opportunity to work with Frog Environmental again in the future.”

Colin Mackay, Environmental Sustainability Manager, Balfour Beatty Power Transmission and Distribution (Scotland)

Award-winning design

This project won numerous UK Green Apple Awards for Environmental Best Practice in 2023 for:

• Silt management at scale (bronze)
• Best practice reinstatement (bronze)
• Woodland retention (silver)

Frog Environmental are water quality & silt control specialists working with contractors, regulators and consultants within construction, utilities, marine and coastal and public sector industries across the UK and Europe.

We provide innovative solutions with a range of market-leading, sustainable products to help the construction industry with environmental compliance. Follow our news and updates, find out more about our products, or contact us for technical support.