Bayne Stevenson Associates were appointed to undertake detailed site investigations and risk assessments for a proposed flatted residential development on a brownfield site in Leith, Edinburgh.  The site had an extensive industrial past including mills, an iron foundry, a chemical works processing gas works wastes and more recently a petrol station. 

 

The site history was complex with issues identified including possible gross contamination in soils and groundwater, deep made ground, geotechnically poor natural soils and ground gases/hydrocarbon vapours.  An extensive and detailed site investigation was required to fully assess the range of Geo-environmental concerns and to ensure the site could be developed safely whilst obtaining regulatory approvals from the planning authority, SEPA and NHBC.

 

The site lies close to the Water of Leith and the site investigation identified extensive groundwater contamination to be present.  The magnitude of contamination present relative to the standard acceptable concentrations for the groundwater and Water of Leith was resulting in a requirement for site wide remediation of soils and groundwater to a considerable depth, early site remediation estimates were in excess of £1million utilising unsustainable techniques.  Our specialist inhouse Geo-environmental Team undertook a detailed quantitative risk assessment taking account of the groundwater regime and interaction with the Water of Leith to develop site specific assessment limits for the contaminants in soils and groundwater in order to protect water quality in the Water of Leith.  This resulted in the scale of remedial works required to be reduced considerably and that only localised groundwater remediation was required. These works were completed to the satisfaction of all stakeholders allowing Building Warrant and NHBC approvals to be achieved on schedule.