Phase 1 Site Investigation

Phase 1 – Site Investigation, Desk Studies or Preliminary Risk Assessments. This is the minimum requirement for a developer under the planning process and some sites (typically green field sites or sites with very limited previous development) can be dealt with by a Phase I alone without the need for any further work. In this phase, a Conceptual Site Model (CSM) is created to identify pollutant linkages via source pathway and receptor to establish any potential risks from contamination with respect to human health, groundwater and the wider environment. With the CSM a detailed preliminary assessment of a sites environmental setting can be established.

The aim of the CSM is to present data clearly to provide support when in relation to the management and mitigation of contaminated land or groundwater. Once a CSM has been prepared, any gaps or uncertainties in the information will become apparent and can then be considered with respect to further work i.e. Phase II Site Investigation.

Phase 2 Site Investigation

Phase 2 Site investigation. Following on from the findings of a Phase I Preliminary Risk Assessment, typically most sites will require further work subject to the proposed end use. This phase involves intrusive investigation of a site with subsequent chemical sampling and analysis to determine whether or not any contamination is present beneath the site (typically associated with Made Ground and or former site users both on and off site). Advice is then provided with regards the contaminated status of the site with recommendation as to how to manage and deal with any contamination present. The CSM would then be updated to reflect the latest progress of the site investigation process. The ideal Phase 2 Site Investigation would be designed to collect information for the whole site to reduce the need for further investigations. However, on a site that varies widely or has significant levels of contamination further investigations may be required.
Additional site investigation is occasionally required as part of a detailed Phase II site investigation where further, more detail targeted site investigation is required. There can be a number of reasons for this such as poor ground conditions requiring deeper boreholes to facilitate pile design; unexpected areas of contamination or significant levels of contamination that may require further sampling, analysis and delineation. Like the initial phase II site investigation, additional works are generally intrusive, and exploratory holes would be spaced on a closer grid and be targeted to investigate specific features across the site. By increasing the density of testing areas, a more detailed picture of the site can be built up. This is particularly good for sites that have large variations in the composition of the ground. Further tests on the soils extracted will show the chemical composition of the soils and will give an indication of the type and volume of remediation required ultimately allowing our clients to manage the costs of this process.

Phase 3 & Phase 4 Site Investigation

Phase 3 Remediation. Following the results of the Phase II Site Investigation, some sites will be deemed contaminated with respect to the proposed end use and therefore require remediation to make the site suitable for use. Whilst GeoCon are not a remediation contractor, we do provide advice on how to remediate the site. GeoCon prepare remediation strategies (remediation statements) which are then used as a document to advise on the most appropriate method of remedial action.

Phase 4 Validation. If a site is deemed contaminated and remediation is required, GeoCon offer validation support whereby our team of environmental consultants will validate all works to provide evidence to the Local Planning Authority (LPA) to confirm that the remediation activities have been carried out correctly and in accordance with the remediation strategy. This is typically via a watching brief, sampling and analysis and provision of a validation report which would include records and photographic evidence to support the process. On complex sites or with respect to groundwater contamination alternative methods would be used.

Ground Investigation

Ground Investigation is necessary where geotechnical information is required to provide civil, structural and geotechnical design engineers with precise data and information relating to the ground conditions, groundwater levels, soils and rock horizons, is collected to provide engineering parameters to facilitate geotechnical design. Using a range of appropriate techniques specific to each site, GeoCon execute ground investigations for a wide range of clients and operate under a consultant and contractor capacity subject to individual client requirements and type of project.

Coal Mining Risk Assessment

Coal Mining Risk Assessments are carried out in specific regions of the UK to assess the risk from former shallow coal mining in relation to a development of construction project. GeoCon offer two levels of Coal Mining Risk Assessment, initially a Preliminary Coal Mining Risk Assessment is carried out by collating a range of data and information to establish the risks posed by historic coal mining, and when required an Intrusive Coal Mining Risk Assessment is then executed to investigate any potential risks identified during the Preliminary Coal Mining Risk Assessment. Risks are typically posed by shallow coal seams within influencing depth that have bene worked at some point in the past where voids have the potential to cause structural failure via settlement and or collapse of overlying strata, and from former untreated mine entries which are either left open or poorly backfilled with loose materials again having the potential to cause structural failure via settlement and or collapse of overlying strata. Risks can also be present from hazardous ground gasses.

Soakaway Testing

Soakaway testing, often referred to as percolation testing or infiltration testing, is carried out to support sustainable drainage design for a development or construction project, whereby under current legislation surface water should be discharged in a sustainable manner to reduce the impact on existing sewage systems which in some cases can be over a hundred years old and originally were not designed to meet the demands of todays population and housing increase. Soakaway testing is carried out in accordance with current guidance to provide infiltrations rates to allow drainage engineers to design soakaways for new building and construction projects.