Eastbourne Borough Council
Project Manager name:
The site was the location of a former depot, where activities had involved aggregates storage, waste sorting and vehicle maintenance. Underground fuel tanks founded on the Chalk, asbestos containing material and hydrocarbon impacted fill were present across the site. In addition, the site was undergoing reptile relocation and required maintenance of a reptile exclusion fence. The Grade II listed Bedfordwell Pump house contained a capped abstraction well and required backfilling with clean gravel. The well was connected to a series of person-sized groundwater tunnels (adits) that ran under the site. It was proposed to redevelop the site for low-rise housing with either piled or shallow foundations.
CampbellReith produced a remediation specification to remove hotspots of hydrocarbon contamination, validate the removal of underground fuel storage tanks, abstraction well backfilling and requirements for waste soil disposal. We liaised with the council, ecologist, environmental health officer, Environment Agency and South East Water throughout.
It became apparent that most of Made Ground soils would not meet the remedial target values primarily due to the presence of benzene. CampbellReith derived site-specific assessment criteria using the EA remedial targets methodology and assessment of vapour intrusion and evaluated the risk to the underlying aquifer from a bituminous layer in the Made Ground. This was reasoned to have been associated with gas works waste deposited on the site where a marshy area had been present and in order to provide a base for a balancing pond associated with the former well. Our conclusion was that there was low risk to both future site users and groundwater from the contamination and there was no need to excavate these soil, which would have been prohibitively expense and required a huge volume of imported soils.