Conversion of Garages to Flats, Parkgate Road, Wallington, SM6

Case Study Reference: CS18-04-08

Planning Authority: London Borough of Sutton

Planning Reference: D2017/77760 and CLC2018/00075

Synopsis:

Given the sensitive nature of the development (residential) and the history of the site (garages)  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 initially undeveloped and by 1895 the site formed part of the gardens of the adjoining properties, glass houses were noted on the 1913 map.

By 1969 the site had been further redeveloped and was occupied by Orchard Court.

The planning history of the site was reviewed as part of the desk-based research and the reports associated with the two previous application and the subject were located and studied, no salient information was obtained.

The published geological maps identified the site as being underlain by the Lewes Nodular Chalk Formation. As no publicly available boreholes for the areas were available from the BGS no further information ion ground conditions could be obtained.

Data provided by regulatory bodies identified an electricity substation 13m west as well as a cutting 240m south.

On completion of the desk based research a site reconnaissance

visit was undertaken this confirmed the site comprised of an apartment block with garages on the ground floor.

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 to be present on the site warranted further assessment.  IT was proposed that either the areas of the proposed garden/landscaped areas needed further investigation or remediation based on a reasonable worst case scenario is undertaken as part of the development.

The report was submitted to partly discharge the condition (CLC2018/00075), the recommendations approved and the condition discharged.