Ground stabilisation works at Thames Farm Reading Road, Lower Shiplake

Engineering works to stabilise the ground

The application sought permission for engineering works, including grouting and compaction, to stabilise ground beneath a site with an existing permission for 95 homes.

“The planning history of the site was set out in the report pack with the key factor being that the site had an extant planning permission in place for 95 homes, with the permission being implemented as the access to the site had been constructed. Further construction on site had been halted due to dissolution features being uncovered across the site.”

“The application was for engineering operations to stabilise the ground to enable the housing development to be built. These works would involve compaction grouting, where a substance would be injected into the ground to reduce the void space and improve ground strength. Dynamic compaction would then be used to densify the soil to reconnect any soft spots.”

Minutes

Housing construction halted by underground cavities

The site had an extant permission for 95 homes, already under construction, which had been halted after underground cavities called dissolution features were discovered.

“Dissolution features were described as geological formations created when soluble rocks were dissolved by water which led to cavities and voids underground.”

Minutes

A site above a public water aquifer

The site sat above a principal aquifer, but the Environment Agency and Thames Water raised no objection once a protection strategy could be secured by condition.

“The committee were informed that the site has an underlying principal aquifer, a natural geological formation which holds groundwater. The site was therefore classified as a groundwater source protection zone as there was water abstraction for the public water supply close to the site. The water abstraction facility was located across from the proposed site.”

“As part of the application process, specialist agencies and officers were consulted to provide advice on the impact of the development on the public water abstraction. Following the submission of amended details, the Environment Agency, Thames Water, Oxford County Council (the lead local flood authority), and the in-house drainage officer all had no objections to the proposal.”

Minutes

Officers recommended approval

Officers acknowledged concerns raised about soil and tree planting but found no objections from specialist officers and recommended approval, saying the works complied with the development plan.

“Both the landscape officer and the tree officer had raised concerns over the placement of the site compound which would be located in an area that would include future tree planting in the housing development. Following completion of the proposed engineering works that area would be provided with a restored soil profile.”

“The officer acknowledged that the application was based on a highly complex and technical matter and that there had been no objections to the proposal from the specialist officers who were consulted. As such the proposed ground stabilisation works were seen to comply with the development plan and would enable the delivery of the housing development that had previously been consented.”

Minutes

Parish council, objectors and a supporter spoke

A councillor spoke for the parish council, two objectors including the local MP spoke against the application, a supporter spoke in favour, and the ward councillor also addressed the committee.

Members weighed uncertainty over the aquifer

Members questioned the drainage solution, the sufficiency of evidence without a finalised protection strategy, and traffic, dust and noise, concluding there was too much uncertainty about harm to the aquifer.

“Members asked about other impacts of the proposal including, increased traffic particularly by Heavy Goods Vehicles, dust from the works, and noise. The committee were advised that while there would be an increase of traffic on the A415 corridor, the Highway Agency had not objected. A condition would be included for a Construction Method Statement to deal with issues such as dust and noise and set out mitigation measures for these.”

“Members commented that there was insufficient evidence to assure them that there would be no harm caused to the aquifer and that there were too many, potentially serious, unanswered questions.”

Minutes

Members voted against officers' advice

Members voted to refuse the application, against officers' recommendation, due to the potential risk and harm to the aquifer.

“A motion, moved and seconded, to refuse the full planning application on the basis of the potential risk and harm to aquifer was carried on being put to the vote.”

“RESOLVED: to refuse planning application P24/S2642/FUL as the site was underlain by principal aquifer and was within a groundwater Source Protection Zone with a water abstraction for public water supply at a water treatment works near the site. The application failed to demonstrate that the proposed engineering operations and the ground stabilisation works would not pose an unacceptable risk to the aquifer and public water abstraction.”

Minutes