What plans does the Welsh Government have to mitigate the impact of road runoff from the M4 and other major roads?
The Welsh Government manages more than 145,000 drainage assets across the Strategic Road Network, including the M4 and trunk roads. Investment is prioritised according to asset condition, flooding history, environmental risk and climate resilience.
The drainage programme includes inspecting, cleansing, repairing and renewing assets alongside sustainable drainage and natural flood management measures to slow and treat runoff, reduce flood risk and pollution, provide wider biodiversity and climate resilience benefit.
Studies of high-priority highway outfalls are ongoing and further work is being undertaken this financial year and into the next to develop schemes addressing flooding on the network and environmental risks.