Desk Study

A Desk Study sometimes also known as a Phase 1 or Tier 1 contamination assessments comprise the collation of desk-based research together with the understanding gained from a site walkover. This phase of investigation provides an initial overview of the nature and extent of geotechnical or contamination hazards that may exist.

The desk study typically includes a review of historical maps and aerial photographs, consideration of the geological and hydrogeological setting of the site from published sources, contact with regulatory authorities and retrieval of ground information from database resources. Desk studies are critical in revealing potential ground hazards such as mining hazards, landfill operations, nearby pollution incidents, naturally occurring radon gas, potentially contaminating land uses and pollution incidents. Desk studies also help to understand the wider environmental setting of the site so that potential receptors to contamination, such as groundwater resources, are identified.

The site walkover survey allows the site and its immediate surroundings to be inspected first hand. Potential ground problems, for example significant cracking of nearby structures, can be identified during the walkover. Indicators of potential contamination include distressed vegetation, discoloured soils, polluted water and waste materials. Asbestos containing materials may also be tentatively identified in any structures at the site. An important source of information can also be interviews with people who have worked at the site or live nearby.

The information from the this initial assessment is used to develop a textual and/or graphical model of likely ground conditions. This “conceptual model” is critical in designing an appropriate  intrusive investigation.