Prior Notification Of A Change Of Use From Agricultural Building To 1no. Residential Dwelling, Oldbury Naite, Oldbury On Severn, Bristol, South Gloucestershire

Case Study Reference: 19-07-11

Planning Authority: South Gloucestershire Council

Planning Reference: PT17/5379/PNGR and DOC19/00274


Given the sensitivity of the proposed end of the development (residential) a contaminated land planning condition was attached to the decision notice.

Part A of the condition required a site investigation, which needed to be preceded by a desk study report in order to assess what potential issues were on the site and to ensure that any investigation was targeted to the potential issues and be cost effective.

The desk study report reviews the history of the site (using a combination of Ordnance Survey maps, aerial plates an street level imagery) and data held by regulatory bodies (such as the Environment Agency, local authority, British Geological Survey etc.) .

The first edition map identified a building on site in the same location as the existing building and no evidence of further development on the site was noted, however a pond (in-filled after 2010). Two further ponds were noted in clos proximity of the site, neither of which had been in-filled.

No further significant information was obtained from data provided by the local authority and Environment Agency.

On completion of the desk based survey the sire walkover survey was undertaken, which confirmed the site was occupied by a barn and an area of hard-standing. The building comprised of the main barn area and a lean to structure. As part of the survey the history of the adjoining pond was discussed and were informed the pond had been in-filled for 40 years.

A qualitative risk assessment was undertaken on the potential sources and this initially discounted all but made ground on the site as a credible source f contamination, and given the small garden areas remediation in lieu of investigation was proposed.

The desk study report was submitted with DOC19/00274 (‘PHASE I DESK STUDY REPORT’ dated 12th September 2019 – there are three parts).

The conclusions of the desk study report were queried by the contaminated land officer and the desk study report was revised to include additional information from the client as to the items stored in the barn and an updated assessment of the risk form the pond and made ground. The revised report proposed site investigation on the site as well as in the adjoining pond.

The revised report is available with the same application (DOC19/00274 – ‘PHASE ONE DESK STUDY NOV 2019’ – dated 18th November 2019) with the memo accepting the revised report (‘ENV HEALTH’ dated 16th December 2019).

The Phase II  investigation was undertaken in December 2019, which comprised of the excavation of nine trial pts across the site as well as a trial trench through the in-filled pond.

Made ground was recorded in the trial pits across the site and the pond had been in-filled with a variety of items including a shopping trolley.

The assessment of the made ground confirmed the made ground was not ‘suitable for use’ and remediation was proposed.

Given the potential for gas generation either ground gas monitoring will be required or the removal of the material in the pond  will need to be undertaken to break the pollution linkages associated with ground gases,

The Phase II report was submitted with DOC20/00063  (identified as ‘PHASE II SITE INVESTIGATION REPORT’ dated 17th February 2020)

The memo accepting the report (identified as ‘RNS ENVIRONMENTAL PROTECTION’ dated 15th April 2020) which also advised ground gas monitoring.

The monitoring was undertaken from October 2020 to January 2021 and demonstrated that the pond was not generating sufficient gas to pose a risk to the proposed development.

As of January 2021 the revised report had not been submitted.