A Phase 1 Desk Study forms the starting point for all contaminated land investigations.
In the UK, site investigation typically follows the guidance set out in Environment Agency document CLR 11 ‘Model Procedures for the Management of Land Contamination’, which establishes industry Best Practice.
This methodology set out in CLR11 involves a number of successive stages of investigation, each of which draw on the findings of the previous stage, and become progressively more rigorous and site specific. The principle of this process is to eliminate low risk sites early in the investigation, saving the deployment of resources to assess and remediate more severe contamination.
The first stage in this process is referred to as a Phase 1 Desk Study. It is a relatively low-cost, initial assessment based on available on-line and published data sources and searches sometimes supplemented by a site walkover or environmental audit.
We look at the development history of a site by examining historical Ordnance Survey maps, and a search of statutory environmental databases, allowing us to identify and assess potential contamination risks and former site uses.
We also consider the geological setting, hydrogeology (groundwater and aquifers) and hydrology (surface waters- rivers, lakes etc).
This information is collated and used to produce a ‘Conceptual Site Model’ (CSM). Based on the CSM, and with consideration of the proposed development, a brief qualitative Risk Assessment is undertaken.
Where risks have been identified during the Phase 1 Desk Study, an Phase 2 Intrusive Site Investigation would typically be required to obtain site specific data on ground conditions and chemical quality of soils and groundwater.
Next Stage – Phase 2 Intrusive Site Investigation