Site Investigation Survey and Monitoring
A Site Investigation Survey or Ground Investigation is generally required as part of the planning process when a site is being developed or re-developed.
Site Investigations determine the engineering properties of rock and soil and how they will interact with a planned development, as well as the geological, environmental (contamination) and engineering characteristics of a site.
What Is A Site Investigation Survey?
The overall purpose of Site Investigation is to establish parameters for foundation and substructure design; and to assess the potential contamination risks to humans, property and the environment.
The design and scope for each Site Investigation will depend upon specific circumstances at the site. Previous use of the site, the anticipated geology, and the construction proposals.
There are a variety of procedures and techniques and that can be used, however, it is typical for a Site Investigation Survey to comprise of four phases:
Phase 1 — Desk Study
Phase 2 — Intrusive Investigation
Phase 3 — Remediation Strategy
Phase 4 — Validation
The information obtained from each phase is assessed to ensure the initial objectives of the site investigation are satisfied.
Changes to the scope of the investigation or even the design proposals and construction works might be needed in the light of any unexpected findings.
A Site investigation Survey should include:
- Susceptibility to groundwater levels and flow.
- Underlying geology, and ground and hydro-geological properties.
- Identification of physical hazards.
- Identification of methane and other gases.
- Determining an appropriate design.
- Providing soil parameters for design and construction.
Where a site may be affected by contaminants, a combined geotechnical and geo-environmental investigation should be considered and remediation may be necessary.
It may also be necessary to notify regulatory authorities of findings like contaminants found that had not been previously known about and in relation to waste management and the protection of water quality and resources.
How Important Is A Site Investigation Report?
A Site Investigation Report is generally required to satisfy the various regulatory requirements of Planning Departments, the Environment Agency and Environmental Health Departments.
A comprehensive Site Investigation Survey lowers the risk of unexpected ground conditions during development, time delays, and significant cost implications.
Without Site Investigation there is a potential risk to the health and safety of site workers and the general public. As well as the environmental risks to human health and vegetation.
What Is A Ground Investigation?
The terms Site Investigation and Ground Investigation are frequently confused. A site investigation involves:
- the collation of desk study information;
- appraisal of the data;
- assessment of the ground conditions;
- the provision of an interpretative report.
A Ground Investigation is broadly a more restrictive phase of specialist intrusive geotechnical investigation with associated site monitoring, testing, and factual or interpretative reporting:
- Application Site Condition Report (A-SCR)
- Surrender Site Condition Report (S-SCR)
- Due Diligence – Liability assessments of potentially contaminated sites [for land purchase].
- Risk Assessment – Risk to human health and risk to controlled waters.
- Characterisation of waste – Disposal to landfill or on-site re-use. Disposal costs of excavated materials can make projects uneconomical. WAC and WM3 testing to characterise waste materials for management and/or disposal, potential alternatives to landfill.
- Environmental monitoring – e.g. Landfill, landfill gas, leachate, groundwater, surface water monitoring as part of closure/permit surrender.
Site Investigation Phase 1 and Phase 2
Broadly, Site Investigation Survey site reports can be put into two main categories. Some examples of when either a Phase 1 or Phase 2 Site Investigation would be necessary are:
Phase 1 – Desk Study Report
Aiming to derive indirect evidence regarding ground conditions. This phase contains a preliminary conceptual site model (CSM) based on examination of publicly and commercially available data regarding the site such as historical maps, a site walkover survey, and correspondence with the relevant local authority (Environmental health officer/Building control).
Usually, this forms part of the preliminary risk assessment – establishing whether or not there are potentially unacceptable risks associated with the site.
These risks could stem from historic land use leaving a potentially contaminative legacy and/or known engineering abnormals such as compressible ground, running sands, naturally occurring voids, coal, and non-coal mining legacy, hydrological risks and ground gas issues.
Phase 2 – Generic Quantitative Risk Assessment
This phase of a Site Investigation Survey involves the refinement of the preliminary CSM based on the findings of an intrusive investigation.
Intrusive investigations involve breaking of the ground by means of excavation (trial pits) or drilling of boreholes to assess ground conditions, create a soil profile based on encountered materials, take in-situ measurements, collect samples for laboratory analysis (soil, groundwater) and measure ground gases and/or VOCs as and when required.
Phase 2 intrusive investigations, therefore, produce direct evidence of ground conditions and reduce the uncertainty associated with the preliminary CSM.
Experts In Planning Applications
ECL has numerous years of experience providing Site Investigation Surveys and Ground Investigation services to companies in the UK and around the world including Phase 1 Assessments, Phase 2 Intrusive Investigations; (Trial pitting, window sampling, boreholes, groundwater monitoring, soakaway testing) and Waste Characterisation / Waste Acceptance Testing.
ECL will design a site-specific Site Investigation to satisfy your project requirements and any regulatory authorities with all Site Investigations carried out to the relevant British and European Standards.
Our network of local offices across the UK, in Cardiff (Wales), Leeds (West Yorkshire), Newcastle and the West Midlands, allow ECL to provide a cost-effective service nationwide.
ECL service all project sizes from small business to large corporate infrastructure projects.