National Highways Completes Installation of Two Highway Runoff Treatment Facilities Along Lancaster Canal

en.Wedoany.com Reported - On November 9, National Highways announced progress in treating highway runoff pollution along the Lancaster Canal. In partnership with the Canal & River Trust, vortex separation devices have been installed at two key drainage outfalls near the M6 motorway to treat road rainwater runoff and reduce the discharge of sediment and associated pollutants into the canal. Since the facilities were put into operation, local canal water quality has improved, and National Highways plans to extend the treatment work to other sections of the canal.

This treatment work is part of National Highways' 2030 water quality improvement plan. Published in 2023, the plan initially identified 1,236 road drainage outfalls and infiltration facilities that may pose a higher pollution risk. Following site investigations, technical assessments and priority adjustments, National Highways updated its priority treatment list in September 2026, and currently 250 priority treatment locations have been identified.

Pollutants in road rainwater runoff mainly originate from vehicle operation and road wear, including tire wear particles, metallic substances from braking systems, fuel and lubricant residues, and sediment washed away by rainwater. These substances enter rivers, canals and groundwater systems through road drainage pipes, and some pollutants attach to sediment, affecting the ecological environment of water bodies and riverbeds.

According to National Highways' technical approach, highway runoff treatment will select treatment facilities based on the topography, drainage conditions and receiving water environment of different locations, mainly including constructed wetlands, filtration drains and underground vortex separation devices. Among them, vortex separation devices intercept sediment, oils and debris in runoff through underground treatment tanks; constructed wetlands use shallow water areas and aquatic plants to filter pollutants; and filtration drains treat runoff through gravel-filled layers and perforated drainage pipes. The Lancaster Canal project uses vortex separation devices.

Under the UK's Road Investment Strategy 3, National Highways is required to complete pollution treatment at 190 to 250 high-risk drainage outfalls and infiltration facilities by the end of the 2030/31 financial year. The work covers motorways and major trunk roads across England, and treatment measures include adding new treatment facilities and upgrading existing drainage systems.