PWA Geo-Environmental Limited
The Desk Study or Phase I is the first step in the process of geo environmental site investigation of a site prior to development.
It is probably the most important stage of the investigation process allowing you to see the way the project is likely to progress. It can highlight potential cost savings as well as potential problems and can delineate the whole process of investigation, remediation and development of a site allowing you to assess the potential cost and/or savings on a stage by stage basis.
The desk study pulls together all the available information on a site prior to any intrusive investigations and allows the construction of an initial Conceptual Site Model which identifies potential risk such as contaminated land or abnormal foundation costs. The Desk Study can be used in the first part of the Regulatory Approval such as the Local Authority (LA) or Environment Agency (EA), process where it can fulfil a planning condition that requires discharging.
PWA Geo Environmental engineers, can provide comprehensive and cost effective geo environmental Phase I Desk Study report services in line with CLR7 and CLEA Guidelines within your required timescales.
The Site Investigation or Phase II is the intrusive part of the investigation and may include any or all of the following:
trial pits: hand or machine excavated, usually with a JCB, to assess the macro-fabric of the shallow ground conditions in soils and to provide samples for contamination and geotechnical testing
mini rig boreholes: a small machine that can fit through a standard doorway used to assess the shallow ground conditions in soils and to provide samples for contamination and geotechnical testing
cable percussive boreholes: a large tripod machine used to assess the shallow and deep ground conditions in soils and to provide samples for contamination and geotechnical testing
rotary boreholes: generally a lorry or trailer mounted rig used to assess the subsurface ground conditions in rock. Can be open hole which does not produce samples and is mainly used to check for shallow mine workings; or cored which produces a core or rock that can be logged and strength tested
Gas and water monitoring wells: Points within the groundmass to continuously test for the groundwater level and/or gases such as methane, carbon dioxide and oxygen. The pipes are generally between 19mm and 50mm in diameter
geophysical surveys: Such as magnetrometer surveys or infra red aerial photography to locate mineshafts, ground penetrating radar for non invasive study of changes of ground conditions
in situ testing such as hand vanes in trial pits and Standard Penetration Tests and cone penetration testing in boreholes to assess soil strength, pH, immuno-assay for limited on site contamination assessment
contamination and geotechnical laboratory testing: the standard PWA Geo Soil suite tests for a range of common contaminants including metals and organics. Geotechnical testing includes soil and rock testing, plasticity of cohesive soils for heave potential and compressibility testing
Reporting: Our geo environmental engineers can provide robust accessible reports that are suitable for submission to regulatory bodies such as the Local Authority (LA) or Environment Agency (EA)
The ground investigation is based on the findings of the desk study and the requirements of the development of your site. The Conceptual Site Model is refined, the risks are positively defined and the initial remedial measures outlined.
If the site contains unacceptable risks from contaminants they may require removal or encapsulation. The site investigation can identify levels, hazards and materials on site using Soil Guideline Values (SGVs) or Generic Assessment Criteria (GACs).
Our geo technical engineers can save you money by undertaking targeted, cost effective site investigations transparently priced on an Bill of Quantities re-measure basis.
The Geo Environmental team has over 15 years experience of planning, supervising and report site investigations to BS5930, BS1377, BS10175, Eurocode 7 & CLEA.
The Remediation or Remedial Strategy is based on the findings of the ground investigation, and is usually required for Regulatory Approval as part of the planning process. It is an outline of the work required to make your site suitable for the proposed end use.
PWA Geo-Environmental Engineers Limited can act as your consultancy specifically for the supervision of Specialist Contractors undertaking remedial techniques such as:
In situ ie steam injection, high temperature thermal conduction, electro-kinetics, surfactant Injection, Bio-remediation, natural attenuation, chemical oxidation, dual or multi phase extraction
Ex situ ie bio-remediation, vapour extraction
Air sparging, processing, stabilisation, excavation, disposal
The Validation Report is the confirmation provided to confirm the Remedial Strategy has been completed satisfactorily and mitigates any risks identified in the Desk Study or Ground Investigation. The Validation Report can be used for Regulatory Approval where it can fulfil a planning condition that requires discharging. It is generally the final hurdle to be passed to allow you to sell or hand over your site to the final end user.
PWA Geo-Environmental Engineers have over 15 years experience of supervising and validating Remedial Strategies.
For more information please contacts via email site@pwageo.co.uk or phone us on 0113 2372929.
