Redevelopment of Agricultural Building, Brook Lane, Flitton, MK45
Case Study Reference: CS23-03-15
Planning Authority: Central Bedfordshire Council
Planning Reference: Central Bedfordshire Council and CB/20/00045/FULL
Synopsis:
Given the sensitive nature of the development (residential) and the history of the site a contaminated land planning condition was attached to the decision notice for the proposed development.
The first stage of discharging the condition was to prepare a Phase I desk study report in order to determine if the site has the potential to be impacted by elevated levels of contamination, and to determine the source as well as the likelihood of the risk occurring.
A desk study determines what issues relating to historical contamination may affect the site, this is undertaken by reviewing the site history using a combination of O.S. maps, aerial, plates and street level imagery, a review of data held by regulatory bodies (Environment Agency, local authority, BGS etc.) as well as a site walkover survey.
The history of the site and surrounds were researched using a combination of Ordnance
Survey (O.S.) maps, street level imagery and aerial plates, this revealed the site was not developed until between 1988 and 1993.
The planning history of the site was reviewed as part of the desk based research and reports associated with any previous application were located and studied and no previous applications were noted.
The published geological maps identified the site as being on a geological boundary between head and alluvium) a potential source of ground gases). The bedrock was given as the Woburn Sands Formation.
Data provided by regulatory bodies identified a pond to the south, reservoir to the north and a graveyard to the east of the site.
The sensitivity of controlled waters was undertake
n to determine if the site posed a risk to the nearby water bodies, this concluded that whilst the bedrock was a principal aquifer and the site was within a Source Protection Zone (III) the groundwater was of low risk due to the history of the site and further assessment was not warranted.
On completion of the desk based research a site reconnaissance visit was undertaken, this confirmed the site comprised of a barn, which at the time of the site visit was used for general storage and storage of vehicles, no evidence of staining was noted. A tank was noted during the site visit, however it was confirmed it had been decommissioned and then brought onto site.
Once the walkover survey was completed a qualitative risk assessment was undertaken on the potential sources of contamination identified in the desk study report in order to determine if any warranted further investigation, this concluded that the potential for made ground on the site as well as the gassing potential of the underlying alluvium warranted further assessment.
The report concluded that remediation in lieu of further assessment (incorporation of gas protection measures and removal of made ground from gardens and landscaped areas) was preferable.
The Phase I report was submitted to partly discharge the contaminated land planning condition (CB/23/02104/DOC) with the proposals for remediation in lieu of further works accepted.
Once the proposals had been accepted the remediation strategy / implementation plan could be prepared which provided details of the gas protection measures as well as the methodology of the validation regime of the installation. This was submitted to discharge the next part of the contaminated land planning condition (CB/23/03065/DOC) allowing the development to commence.
