Geoenvironmental Planning Support, RAF Boulmer Admin Site

DBS Environmental LOCAL AUTHORITY PART 2A SUPPORT

Geoenvironmental Planning Support, RAF Boulmer Admin Site

DBS was involved in the characterisation of a former administration site operated by the MOD as part of RAF Boulmer at Longhoughton, Northumberland on behalf of The Northumberland Estates.

  • Client: The Northumberland Estates
  • Date: June 27, 2015

Summary

DBS was involved in the characterisation of a brownfield site at Longhoughton, Northumberland on behalf of The Northumberland Estates. The site was a former administration site operated by the MOD as part of RAF Boulmer.

The site was in military use from first development until the site closed and decommissioning commenced in the late 1990’s, with final building and structure clearance undertaken post 2002. The final decommissioning work was therefore undertaken after the commencement of the Defence Estates (DE) Land Quality programme, which was introduced in 1995. The site was left as open grassed ground upon decommissioning, although areas of hardstanding and former roadways remained.

When in use the site accommodated a boiler house and district heating system, various stores, administration buildings, workshops, fuel storage and an electricity substation.

The Northumberland Estates identified the site for a new camping and touring facility. DBS were employed to review all of the existing desk study and intrusive investigation and risk assessment information prepared for the site by DE and others, and to scope and execute a new investigation in order to further quantify risks and potential constraints at the site from contaminated land, and to provide information to support a planning application for a change of use at the site.

The scope of DBS’ work was undertaken in full compliance with the requirements of the new National Planning Policy Framework (NPPF) which came into force in March 2012.

Site appraisal commenced with a robust review of existing information prepared by others, this revealed that a recent Phase 1 Desk Study report was available for the site that provided a comprehensive initial Conceptual Model, and a very comprehensive ground investigation had previously been undertaken at the site in the 1990’s, and that the investigation was highly targeted at former buildings and structures of the camp.

This left large areas outside of the activity areas that had not been investigated, but provided comprehensive data on areas that had.

Based on this data review, DBS scoped a new investigation in order to provide contemporary information on ground conditions, to plug data gaps, and to obtain controlled waters information. The scope of work involved undertaking a ground investigation using a grid system with sampling on a herringbone arrangement, this provided data that complimented the previously targeted investigation, and helped to minimise costs to the client by reducing the investigation requirements on site whilst providing confidence that all risks were being systematically appraised using a non judgemental sampling strategy.

The investigation was also designed to obtain geotechnical information at areas of the site proposed for new buildings.

The investigation comprised the sinking of window sample boreholes using a Terrier rig, with installations for gas and groundwater, along with mechanically excavated trial pits. Surface water samples were also obtained from a stream bordering the site. A DBS environmental engineer supervised the work on site full time, logging all of the arisings, and taking samples for subsequent laboratory analysis in accordance with our Quality Control procedures. A PID was also used to screen samples on site for volatiles.

The resulting site chemistry information was used to prepare a Phase 2 Ground Investigation report, along with a Generic Quantitative Risk Assessment (GQRA) for human health and controlled waters. This allowed the initial conceptual model to be revised and constraints identified. Gross contamination was generally found to be absent from the site, localised hotspots of contamination were identified but were at depth within the soils at the
site, as such a sensible strategy for remediation of the site was able to be formulated which comprised localised source removal and pathway modification.

The final report also provided foundation solutions for new buildings.

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