Click here for a printer-friendly page. Phase One Case Studies
Phase 1 Case Studies
Project: Former maintenance depot Location: March, Cambridgeshire Client: Local Authority
Overview: A local authority was looking to sell one of its properties for residential redevelopment and as part of the sales pack approached BRD to undertake a desk study and site walkover. The BRD Phase 1 investigation of this site revealed the presence of asbestos containing materials within the buildings and a potential contamination risk from the past spillage of fuels and oils at this former highways maintenance depot. Adjacent marshland was also identified as a potential gas risk. The report concluded with detailed recommendations for the Phase 2 intrusive investigation of the site. BRD were subsequently awarded the investigation contract through a competitive tender process.
Project: Former isolation hospital Location: Eastbourne, East Sussex Client: National Housebuilder - Strategic Land Department
Overview: A former Victorian isolation hospital was proposed for redevelopment with residential housing and public open space. The developer approached BRD to provide assistance in respect of the contamination assessment required as part of the Environmental Impact Assessment (EIA) necessary for a development of this size (at approximately 23 hectares). The study involved an extensive walkover of the derelict hospital buildings and grounds, an asbestos survey and a review of the hospital's plans and records. The desk study review identified several potential areas for ground contamination, such as the boiler house and the workshop areas, and these were subsequently investigated in a Phase 2 investigation. BRD worked as part of the project team in delivering the EIA to the local authority for consideration.
Phase Two Case Studies
Phase 2 Case Studies
Project: Former printing works Location: Luton, Bedfordshire Client: National Housebuilder - Regional Office
Overview: BRD was contracted to undertake the ground investigation of the underlying chalk strata to collect data for the design of piles. The investigation comprised several boreholes together with a follow on phase of dynamic probing. The investigation highlighted the presence of chalk dissolution features in part of the site extending several metres beneath ground level. In addition to completing these ground investigation works, BRD was also contracted to supervise the remediation of the site which included the excavation of contaminated soils and removal of several underground tanks.
Project:Former landfill site Location: Cambridgeshire Client: Regional house builder of a major civil engineering contractor
Overview: The Phase 1 desk study revealed the presence of a quarry on this development site that was subsequently filled in. BRD undertook the investigation of this site with a combination of trial pits to define the lateral extent of the historic landfill and cable percussive boreholes to prove its depth. The boreholes were drilled employing techniques to ensure that the underlying aquifer was not compromised by the investigation. An extended period of gas monitoring was undertaken in order to assess the risk from harmful gases. The results of the investigation were developed into a capping remedial solution that was acceptable to the local authority, Environment Agency and National House Building Council. BRD were also involved in the preparation of a foundation works risk assessment to confirm that the chosen piling method did not present a risk to groundwater.
Project: Former industrial estate Location: Biggleswade, Bedfordshire Client: Regional house builder of a major civil engineering contractor
Overview: BRD was commissioned by a house builder to provide a detailed contamination and geotechnical assessment of a former industrial estate they were intending to redevelop with residential housing. In addition to contaminative processes undertaken on the site, there were also several above and below ground fuel tanks to be investigated. The site is located over a major aquifer and therefore required assessment of the groundwater regime as well as the soils. A combination of hand dug pits, trial pits, window samples and boreholes were conducted to provide information on the underlying ground conditions. The findings from the investigation were expanded in to a remediation strategy. BRD was subsequently commissioned to deliver the remediation as a single contract.
Project: Residential garden Location: Stanton Harcourt, Oxfordshire Client: Local developer
Overview: In assessing whether soakaways were a potential drainage option at this small residential development, BRD was approached by the client to undertake a number of soakage test pits in accordance with BRE Digest 365 “Soakaways”. A total of three pits were filled repeatedly with water and the soakage infiltration rates recorded. The subsequent calculations showed that the disposal of collected water to soakaways was a feasible option at this site.
Risk Management Case Studies
Risk Management Case Studies
Project: Former petrol station Location: Kidderminster, Worcestershire Client: Local developer
Overview: Following a Phase 2 investigation of this former petrol filling station, BRD was commissioned to supervise the subsequent remediation works. Petroleum contamination had locally affected the surrounding soils, however, was not found to have impacted the underlying aquifer. BRD's package of work involved formulating a remediation strategy, overseeing the decommissioning of the fuel tanks and fuel lines together with supervision of the removal of the tanks and the excavation of the contaminated soils. The Environment Agency and the local authority were consulted at all stages during the remediation. The completion report produced by BRD detailed all of the works conducted including all of the validation testing that proved that the site had been successfully remediated to the agreed targets.
Project: Residential gardens Location: Potton, Bedfordshire Client: Local House Builder
Overview: A small development proposed for construction in the rear gardens of several existing domestic properties. A previous investigation by another consultant had identified naturally elevated arsenic concentrations and had recommended a remedial solution involving the removal of soil and replacement with imported material. Instead, BRD undertook a site specific risk assessment including consideration of the bioavailability of the arsenic through the use of Physiologically Based Extraction Test (PBET). The assessment concluded that the naturally occurring arsenic concentrations did not pose a significant risk to the health of future residents and therefore no remedial works were required. The assessment was accepted by both the local authority and National House Building Council thus saving the client unnecessary expenditure on remedial works.
Project: Former car showroom, petrol station and service workshops Location: Bedford, Bedfordshire Client: Regional house builder of a major civil engineering contractor
Overview: BRD provided a complete design and build reclamation service to the client for a fixed price. The contract included preparation of the remediation strategy, management of the demolition of the former garage buildings and removal of several large underground fuel tanks, production of recycled aggregate, groundwater control, excavation of contaminated soils and disposal offsite. Validation of the site was achieved through the systematic collection of samples for laboratory analysis, post reclamation ground investigation and soil vapour survey. The validation report detailing the ground conditions following remediation was accepted by the local authority and National House Building Council. BRD had also completed the earlier site investigation works and later tested the imported topsoil used within garden areas at the development. The local council later approached BRD for permission to use our reports for internal training purposes as examples of the quality that should be expected from other consultants.
Project: Former bakery Location: Swindon, Wiltshire Client: Regional House builder
Overview: BRD played a key role in negotiating a framework for managing the remediation of this site with the regulators. Extensive leakage of diesel from an underground tank was mapped by additional BRD investigation. The remedial work involved the bioremediation of approximately 10,000m3 of contaminated soil for reuse on site together with a capping of garden areas and construction of a boundary cut off wall. BRD supervision and management ensured the remediation was integrated into the house build programme to ensure delivery of this development at the earliest opportunity.
