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Nov 2021

Last Updated: 10/11/2021

News

Sinkhole experts urge councillors to consider new site for Ripon pool

by John Plummer

| 10 Nov, 2021

They have urged Harrogate Borough Council to postpone a decision on the leisure centre tonight after a newly released report revealed the Dallamires Lane site could be permanently plagued by the threat of sinkholes.

ripon-21st-oct-2021-leisure-centre-and-swimming-pool

Two sinkhole experts have urged councillors to consider finding an alternative site for the new Ripon leisure centre and pool — a month before it is due to open.

Their comments come after a newly released report by engineering company Stantec revealed the Dallamires Lane site could be permanently plagued by the threat of sinkholes.

Harrogate Borough Council commissioned the report after a void was discovered last year.

Michael Constantine, the council's head of operations, has recommended councillors approve remedial work at a cabinet meeting tonight. But the experts have urged them to postpone a decision and take a longer-term view of the issues raised in the report.

Stanley Mackintosh, a chartered engineer in Ripon, said in a letter to the council that there was a "substantial risk of sudden catastrophic collapse" of land on the site due to the weak "pie-crust" nature of the land.

He told the Stray Ferret:

"The long term safety implications and unfathomable future costs seem to be very seriously underestimated by the council."

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The Stantec report reveals there has been substantial and ongoing ground instability beneath the leisure centre building over three decades. It suggests the only way to avoid ongoing problems and costs is to find another site because the bedrock beneath the void is significantly disturbed and collapsed.

Mr Mackintosh, who has consistently raised concerns with the council about building a pool on land with a history of ground instability issues, said the report to councillors tonight contained "inaccuracies and omissions".

He told the Stray Ferret:

"I am concerned that the new connecting walkway bridge may be a structural weak link, potentially unsafe for routine use by public and staff.

"As a chartered engineer, it remains my opinion that continuing to use the first floor of the existing leisure centre – and the said 'weak link' aerial walkway access to it– is an inadvisable and unnecessary risk to public safety.

"We should each, perhaps, honestly ask ourselves: “What kind of catastrophe at this Ripon Camp Close development, in part consequential to our own choices or inaction, could ever be justified?"

'Gradual collapse'

Dr Alan Thompson, a geologist and director of director of Cuesta Consulting in Somerset, said he believed "gradual collapse" was a likelier scenario than sudden collapse.

But he agreed the council should give greater consideration to relocating to another site — an option councillors are recommended to reject tonight. Dr Thompson said:

"Given the huge and ever-increasing costs of the proposed works at Camp Close, the relative cost-benefits of relocation need to be seriously investigated as an alternative option, and not just dismissed out of hand, as the councillors are being asked to do.

"I do suspect that there will be ongoing ground instability at the Camp Close site and that, even with the proposed mitigation works, this risk will never be entirely eliminated. This is why the alternative option is so important."

Stantec's 277-page report says there is a "residual risk" of "catastrophic ground collapse" at the site, where a six-lane pool is due to open on December 8.

The top floor of the adjoining leisure centre is also due to open but the ground floor will remain shut while the remedial work is carried out.

Construction firm Willmott Dixon was awarded a £10.2 million contract in 2019 to build the pool and refurbish the leisure centre. It is not known how much the costs have risen to.

Mr Constantine's report to councillors tonight says:

"The consulting engineer has stated that in their professional opinion a do nothing approach is unacceptable from a public safety perspective.

"By undertaking the works, which may also include installing post works monitoring equipment, the council will ensure that it has put in to place adequate mitigation to address the risks highlighted within the Stantec report.

"It is noted that the consulting engineer has highlighted that pile or pile group failure itself is unlikely to be catastrophic and would most likely be observed as a gradual settlement, structural cracking, and distortion of the structure."

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Sinkhole experts urge councillors to consider new site for Ripon pool

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'Gradual collapse'