Fears over threat to drinking water

RESIDENTS have made an official complaint over fears that drinking water in the Henley area could be affected by the construction of a housing development above an aquifer.

Plans to use piling to secure the foundations of the new homes at the former Wyevale Nursery, off the A4155 Henley-Reading road, have been submitted by Beechcroft Developments to South Oxfordshire District Council, the planning authority.

The site is above a chalk aquifer which provides a public water supply to Henley, Harpsden and Shiplake and is in an area designated as a Source Protection Zone 1 by the Environment Agency.

The Thames Farm Action Group is concerned that the piling would physically disturb the aquifer and threaten the important potable water source.

Twelve groundwater abstractions are recorded within 250m of the site, relating to the Harpsden pumping station, which is operated by Thames Water.

The group previously campaigned against the proposed development at the former Thames Farm, which is adjacent, on the grounds that the foundations could pollute or disturb the aquifer.

Taylor Wimpey proposed pumping grout into the flood-prone ground to fill a number of weak spots in the bedrock and stop them collapsing. The development, called Regency Place, has still not been fully approved because of this.

This week, the group submitted a complaint to the Office for Environmental Protection, arguing that the Environment Agency is not carrying out its regulatory role in considering the potential damage to the aquifer.

It claims that the agency is not following its own approach to groundwater protection, which states: “Within SPZ1, the Environment Agency will normally object in principle to any planning application for a development that may physically disturb an aquifer.”

The district council granted outline planning permission for the former garden centre to be reddeveloped into 40 dwellings and a new commercial unit in November 2019.

Beechcroft Developments bought the land in 2021 and the demolition of the existing greenhouses took place in January.

A planning application for reserved matters was approved by the council in February. This includes the condition that: “A source protection strategy detailing how the developer intends to ensure the water abstraction source is not detrimentally affected by the proposed development both during and after its construction shall be submitted to and approved in writing by the local planning authority”.

Another condition states: “In the event that piling is required, a piling method statement shall be submitted to and approved in writing by the local planning authority prior to the commencement of the development […] to ensure that the proposal does not harm groundwater resources.”

In March, Beechcroft submitted planning applications to discharge the conditions, stating: “In view of the potential chalk solution features on site, and the anticipated structural loading from the development, traditional spread footings are not considered suitable.

“Piled foundations are considered to be the most suitable foundation type.”

A report submitted in support of the application stated: “SFA [sectional flight auger] piles are the most suitable form of piling to ensure that the presence of the piles does not constitute any greater likelihood of downward migration of contaminants than before the piles were installed.”

The action group employed engineering hydrology firm JBA Consulting to analyse the information submitted by Beechcroft.

Chairman Peter Boros, from Shiplake, said the company felt it was “deficient” as it lacked a proper risk assessment of the impact on the aquifer by the piling and full modelling of the groundwater on the site. He said: “If the information is deficient, [the council] can’t make sensible and well-advised decisions.”

Mr Boros raised concerns about the effect of driving piles through the aquifer with the Environment Agency in the summer.

The agency replied: “We have no concerns that the proposed development would have an adverse impact on groundwater resources.”

The residents claim this response is “inadequate” and the agency is not following its own procedures.

Mr Boros said: “It is pretty appalling for an area of land of the highest level of protection for it to be dealt with in such a lax manner. The agency and others say they are short-staffed and have too much to do but water is a fundamental right for people. If there is any particular risk of disturbance of an aquifer it’s something the agency must look at. It’s one of the key triggers in statutory guidance. I’d like to see them deal with this properly and carry out a proper analysis and risk assessment for the potential disturbance or contamination of aquifers.”

He said the council should have delayed granting outline permission.

“When a developer gets outline planning permission he expects to be able to develop the land but the due diligence should have been undertaken when it was first submitted,” said Mr Boros. “It’s coming very late in the day. The facts are that our area is known for gravel extraction, it’s known that there are chalk layers in the ground so it’s not rocket science to know that these are ideal conditions for sink holes and voids to exist underground.

“It’s rather disturbing that a statutory body like the district council doesn’t have a register of those areas so that automatically when applications come in for these areas they are flagged as something requiring sepcial review before consent is granted.

“When the reserved matters application came in in 2021  JBA flagged up a raft of problems with it. I think that is why the council introduced numerous conditions that needed to be fulfilled before development could take place. That was the first warning that there might be problems. Really at that point they should have said, ‘Do your due diligence’ but they didn’t unfortunately.”

The action group is supported by both Harspden and Shiplake parish councils.

A district council spokeswoman saud: “We’ve undertaken the necessary consultations as part of the planning application process to ensure this matter has been appropriately and carefully examined. We did not consult the Environment Agency on these applications as it is not a statutory consultee for the type of development proposed.

“Despite this, we have liaised with the agency regarding the potential risks to groundwater resources from the development. It confirmed the developer had taken all necessary steps to ensure groundwater will not be impacted.”

A Beechcroft spokeswoman said: “The information submitted by Beechcroft to discharge the outstanding prestart planning conditions is extensive and the council has consulted widely including with Thames Water, the Environment Agency and its own drainage engineer.

“Other than some minor comments made by the agency in relation to sampling groundwater during construction, there are no objections from the statutory consultees and therefore no reason why work shouldn’t start shortly.”