Five Steps

There are usually five stages to carrying out Site Investigation Procedures

1. Desktop study
2. Walkover survey
3. Detailed site investigation
4. Remedial treatment
5. Long-term monitoring

The desktop survey is based on the old military adage "time spent in reconnaisance is never wasted". The purpose of the study is to identify change in land use, via Ordinance Survey maps, Kelly's Trade Directories and other historical publicly available records.

Having identified potential contaminative uses that the site may have been put to, an initial walkover survey identifies potential problem areas on the ground. Contamination of soil, groundwater and building fabric all impart valuable visual information indicating areas requiring follow-up. Old foundations, backfilled areas, subsidence and poor drainage are also indicators of change of use, identifying areas requiring detailed sampling.

Pitting, trenching and drilling reveal the sub-surface characteristics of the site (although with decreasing accuracy as regards sample precision). Soil and water samples are taken for chemical analysis to identify contaminants, and geophysical surveys can yield valuable information about sub-surface features. In the light of planned future usage of the site and its geology and hydrology an assessment of risk can be carried out.

Groundwater monitoring is used as an indicator of the integrity of the sites remediation