Long-term environmental treatment and monitoring at E18 Motorway are showing positive results in watercourses affected by acidic runoff from rock deposits created during construction.
The project operates three treatment plants to improve water quality before runoff enters the surrounding environment. At Stordalen, for example, water is treated to reduce aluminium and other metals before being discharged into Stordalsbekken.
The latest environmental review identified stable pH levels, declining concentrations of several metals and encouraging signs of ecological recovery. Fish were recorded in Skomedalsbekken for the first time since 2006.
Following its review of the project’s 2025 Annual Environmental Report, the County Governor of Agder agreed that several monitoring activities can now end or be reduced. Targeted monitoring will continue in locations where further evidence is required.
This progress reflects the sustained collaboration between Agder OPS Vegselskap, the Norwegian Public Roads Administration and the environmental and operational teams involved.
