The Welsh Government is admitting the Brynglas Tunnels drainage system is struggling to cope when there is heavy rainfall.
This comes after the weekend storms caused a lane closure at the M4 tunnels in Newport.
Speaking to the South Wales Argus, the Welsh Government explained that the closure on the westbound carriageway was due to an issue with standing surface water.
A spokesperson told the paper, “There was an issue with standing surface water (not flooding) on the westbound carriageway at the entrance to Brynglas tunnels on Sunday morning which subsided when rain eased.
“There was also some standing water on the entrance to the eastbound carriageway during this rainfall period which was dealt with.
“This is not unusual at the entrances to Brynglas Tunnels when there is heavy rainfall as the drainage can struggle to cope with the volume of surface water particularly if the gullies are affected by leaves/debris as is the case this time of year.”
(File picture – Traffic Wales Twitter)