Flood-prone culvert subject to increased inspections

Twm Owen, Local Democracy Reporter

A culvert with a screen to prevent debris washing into the Severn Estuary is now being regularly inspected following flooding.

The trash screen shields a culvert underneath the M4 at Caldicot and is intended to prevent debris reaching the estuary from the Nedern Brook but has previously been blamed for flooding in the area.

Councillor Maria Stevens, who represents the town’s Severn ward, claimed part of the Severn Bridge Industrial Estate was previously flooded as sluice gates at Deepweir hadn’t been opened.

The Labour councillor told flood risk manager, Ross Price, who was presenting the latest draft of the council’s flood risk management strategy to councillors, “the clue’s in the name, Deepweir.”

She said there had been a dispute whether the gates were owned by Monmouthshire County Council or Wales’ environmental body, Natural Resources Wales and asked whether that had been resolved.

Mr Price said Natural Resources Wales has responsibility for the Nedern Broook as it is a main river while councils are responsible for managing the risk from “ordinary” or smaller watercourses.

A previous flood report had highlighted issues with the screen, which Mr Price said is owned by National Highways the UK Government agency that is responsible for both Severn Bridges.

“We made recommendations to them they get a camera on the trash screen to aid monitoring, we do that at a number of locations,” said council officer Mr Price.

“They didn’t go down that route eventually but changes have been made to the inspection routine and it is more robust.”

Mr Price said there are now more regular inspections of the screen and specific checks are made during bad weather when amber warnings have been issued.

He also said the council had recommended the agency has a manual way of opening the screen as its hydraulic system had to failed to open the screen due to pressure on it, which he said was added to from debris.

Natural Resources Wales, which carries out maintenance on the brook towards the end of every calendar year, has also agreed to no longer leave debris from its clearance works in place.

The council has been working on its revised flood risk management strategy, which also includes flood risk plans for the county’s nine catchment areas, since last year which also included a public consultation in September and August 2025.

Mr Price said severe flooding last winter, including Storm Claudia which hit Monmouth in November, had delayed that work.

“Publication was delayed due to widespread flooding across Monmouthshire last winter and all staff were diverted to responding to those devastating flooding events.”

The strategy, which includes the flood risk action plan that was previously a standalone document, has been drawn up in line with guidance from councils and the Welsh Government and is intended to complement the government’s overall flood risk strategy for Wales.

It is intended the council strategy will be considered by its ruling Labour/ Green Party cabinet in September and it can then be submitted to the Welsh Government for approval.

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