A Walkover Survey is a key part to the Phase 1 Desk Study and includes a visit to undertake a visual assessment of the site and its immediate surroundings. Photographs are usually taken and any potential ground problems or contamination sources identified during this reconnaissance which may not be evident from the historical map search. These can include, for example, above and below ground tanks, asbestos containing materials and any ground stability issues.
The Desk Study should be carried out as the preliminary stage of any investigation and is typically required to satisfy planning conditions. The aim is to formulate an initial conceptual site model (CSM), which highlights the potential sources of contamination, receptors and the pathways between them. This “conceptual model” is critical in designing an appropriate Phase 2 intrusive investigation. However, it should be recognised that both phases of investigation are commonly combined into a single contract in order to save time and reporting expenses for our clients.
Under current legislation the provision of a desk study is typically a minimum requirement when submitting a planning application. The presence of contamination is a concern for the regulatory bodies when considering development proposals. The developers have an obligation to comply with the environmental regulations at each step of the planning, design and construction process, and the local planning authorities have a duty to ensure any investigation and remedial work is carried out in accordance with current guidance to an acceptable level. An environmental risk assessment is a key element in the initial stages of this process. The Desk Study Report follows the recommendations in EA Contaminated Land Report 11 (CLR 11) and EA Guidance on Requirements for Land Contamination Reports.
A comprehensive report will commonly provide the following datasets: