Calstock Parish Council has expressed concerns about taking on long-term responsibility for the new footbridge over the new wetlands beside the River Tamar as the cost of building it soars fivefold to more than £350,000.

Whilst negotiations between the Tamar Community Trust and the Environment Agency remain ongoing over safety concerns, the parish council has also expressed newfound concern over the long-term viability of the site.

Calstock Parish Council heard at their meeting that the cost of building the footpath over a newly created wetland had escalated to £355,000, funded by the Environment Agency and Cornwall Council.

The original estimate had been for £66,000 for a more modest boardwalk to take the footpath by the river over the newly created wetlands.

The parish council has now raised concerns as it would need to would take responsibility for maintaining it, should the Tamar Community Trust, the charity which is taking on responsibliity and ownership of the footbridge, ever fold.

The footbridge built by the Environment Agency remains closed despite having been supposed to have opened to the community in time for Christmas.

Some light was shed on the Environment Agency’s safety concerns about the bridge at the parish council meeting on Tuesday last week. Councillor Alistair Tinto revealed that a process called ‘scouring’ caused by water flowing in and out of the wetland with the tide had been observed to be eroding the riverbank.

The Tamar Community Trust has engaged a geomorphologist and a team of design engineers to investigate what effect this will have on the wetlands site and the bridge.

Cllr Tinto said: ‘As a parish council, we should not take on any obligations until we know that the design is secure and that the Environment Agency can be confident about the site’s long term viability.

‘We need to know what the cost would be should we be called upon to maintain the bridge and the walkway.

‘I’d like the footbridge to be opened as soon as possible as it should have opened on January 13. I get residents asking all the time if I know as a councillor when it will be opening. ’

Cornwall Councillor Dorothy Kirk said: ‘This is a huge issue and it needs a lot of consideration. Snap decisions can be counter productive. This project is something we’ve invested in massively and we need to go forward and finish it.

‘At the moment we’re spending too much time going round and round in circles.’

Once the geomorphologist issues a report with their findings, the parish council wish to have a meeting with the four bodies involved — the parish council’s amenities committee, the Tamar Community Trust, the Tamar Valley AONB and the Environment Agency — to discuss the future of the footbridge and the wetlands project.

An Environment Agency spokesperson said: ‘We are not currently able to provide a date for reopening of the footpath as before permitting it we need to be satisfied the bridge is safe for public access.

‘There is work to be done to install rails to minimise spacing on the bridge to reduce the risk of children and dogs falling through and to block direct access from the banktop footpath into the channel made by the breach.

‘Access at either end of the bridge also needs to be improved. This outstanding work is expected to be completed by 15 April.’