Site Investigation Bristol
Southwest Environmental Limited were commissioned to undertake a reduced scope geo-environment assessment at a site in Bristol. The investigation was retrospective in that construction work had already started.
Bristol City Council are one of the few council nationally who will accept a reduced scope investigation for geo environmental risk assessment. Ordinarily it is required to take a high frequency of samples even of smaller sites, often including ground gas investigations including deep boreholes which can prove very costly. The cost of such investigations when considering build costs for smaller projects can be approaching 10% of project value, which is some cases in inhibitive.
Below is a panoramic photograph of the site at the time of the investigation. The bedrock has been exposed to some depth by excavations for the foundations. You can clearly see the angle of the bedding and the more coal rich bed to the left of the photograph.
|Photograph of Outcrop (or Incrop!)
Just 2 samples were requested by Bristol Site Council. This is a very low number. The samples retrieved showed no exceedances of established “safe” levels. Although Total Organic Carbon Levels in one sample were above those mentioned in CIRIA guidance, likley owing to the presence of coal.
The whole of Bristol is now considered a brown field area. This may seam an overreaction, but SWEL have been surprised by contamination found on “innocent” looking sites in the past. Despite best efforts to categorise a site as low risk without soil sampling it is often the case that if SWEL are pushed to investigate, post Phase 1 Desktop Study will find high levels of some contaminants.