Warning new bridge could contaminate drinking water

Designs for a new £10m bridge could be a public health risk, a council has been warned.

Denbighshire council has been working on plans to replace the old Llannerch Bridge, which collapsed into the river Clwyd during Storm Cristoph in 2021.

But a report to councillors has warned that Welsh Water believed the plans could pose a "high risk" to the drinking supply of 85,000 households due to the drilling needed to build it.

The council said no decision had been made about the next steps.

Llannerch Bridge was a vital link for people in nearby Tremeirchion and Trefnant, who have been campaigning for a new connection for four years after the destruction of the old bridge added an extra seven miles to the journey between the two villages.

A £1.5m design phase has been completed but "significant challenges" emerged relating to the bridge's foundations.

The report said the location was above a freshwater aquifer and Welsh Water have a freshwater abstraction facility next to the site.

The bridge design would involve drilling into the sandstone above the aquifer, which Welsh Water said could risk contaminating the water supply.

No design solution has been found to remove that risk, the report said, so Welsh Water has assessed construction of the bridge to be a high-risk activity.

Insurers have told the council that building the £10m bridge knowing the risks involved would mean it was unlikely to be covered by insurance if the water was contaminated.

Jane Marsh closed her roadside tea hut in Tremeirchion because of the reduction in trade.

She chairs the village pub community enterprise and said they were also missing out on customers.

"Large amounts of people can't get to us or find it too difficult and will go somewhere out of the area. That's a lot of money. It is very frustrating."

Councillor James Elson represents the village of Trefnant and believes there is "absolutely nothing wrong with the design" but the engineering needed to be "fine-tuned".

"Everything is right with the design and I think we need to get around those technical difficulties with Welsh Water," he added.

Tremeirchion councillor Chris Evans said if there were issues with the plans, "we need to go back to plan B, which is a temporary bridge".

"This could be there for 10 years and in that time we can look at different types of funding. Things will change but the crossing needs to be erected.

"It's only 100ft of water. We put people on the moon, it's the 21st Century."

Welsh Water said: "The current designs have been assessed as a high-risk activity that could impact the supply of drinking water to around 85,000 households.

"Any ground drilling work in such close proximity to our existing operational assets could lead to a risk of water supply contamination and a public health risk with wide reaching consequences."

The council said a design stage had been completed to "establish the most viable option" and had identified challenges, but "no decision has been made about the next steps for this project".

On Thursday, the council's partnership scrutiny committee will be asked to provide feedback to the project team and cabinet.