In March this year, the Yorkshire and Lincolnshire Pollution Advisory Group (YALPAG) produced updated technical guidance for developers, landowners, and consultants entitled ‘Development on Land Affected by Contamination’. Here at Sequoia Environmental, we think that this document provides a really good resource for those looking to develop land under the UK planning system. If you haven’t got time to read the whole thing, we’ve included a summary of the key points below:
Introduction
This section introduces the concept of ‘risk’ in relation to land contamination and details the roles and responsibilities of the developer and local planning authority. Importantly, the guidance notes that the potential for contamination should be considered when submitting any planning application, including prior approvals for a change of use.
The introduction also provides advice on how to complete the ‘existing use’ section of the planning application form. The report clarifies that any residential development, comprising one or more dwellings is considered ‘vulnerable’ to the presence of contamination. Sequoia Environmental produced a similar guide recently entitled ‘Do I Need a Desk Study’ which includes a handy flowchart, which you can find here.
In addition, the guidance includes a screening assessment for developments that only comprise a single residential property. This document is included as an appendix and will help to reduce costs for low-risk sites.
Phase 1 Preliminary Risk Assessment
This section details what should be included in a Preliminary Risk Assessment/Desk Study and explains how a Conceptual Site Model (CSM) is constructed. Further information on the development of a CSM can be found here on our website.
A checklist is provided for consultants to include when a desk study is sent to the local authority, to ensure that the submission is complete.
Phase 2 Site Investigation and Risk Assessment
This section details good practice for completion of intrusive site investigation and explains how the results can be used to compile a generic or site-specific risk assessment.
The scope of works for site investigation will be informed by the Desk Study and should be approved by the local authority prior to commencement. Depending on the nature of the site, this may include the collection of soil, groundwater or surface-water samples, or measurement of ground gas. Once accredited laboratory analysis is complete, the concentrations of contaminants identified can be used to inform the risk assessment process. Initially, this should involve a comparison between the observed contaminant concentrations and generic screening values from published sources. If the observed levels of contamination exceed these screening values, then site-specific risk assessment can be carried out using the Contaminated Land Exposure Assessment (CLEA) model. Risks from ground gas and to controlled waters are also assessed at this stage in a similar way. On completion of the risk assessment, a conclusion will be drawn as to whether the site is suitable for its end-use, or whether further risk assessment or remedial works are necessary.
The guidance also includes a second checklist to include when submitting a Phase 2 report to the local authority.
Phase 3 Remediation
There is much more to remediation of contaminated land than just digging up and removing impacted material from a site. This section of the guidance provides a framework for completion of the remedial process.
Prior to the completion of any physical remediation, the first thing that should be completed is a Remedial Options Appraisal (ROA). This document considers the strengths and weaknesses of different remedial options to decide upon the most effective and sustainable approach.
Once a remedial strategy has been chosen, details of how it will be implemented should be submitted to the local authority for approval. A method of verification should also be decided upon to demonstrate that the remedial works have been completed successfully.
The guidance includes details of any permits, which might be necessary during the remedial work and highlights the developer’s responsibility for reporting of any unexpected contamination during this process. A checklist for use when designing and implementing a remedial system is also included.
Phase 4 Verification
The final section of the guidance focuses on verification (or validation), which is used to determine if the remedial work has been successful or if any long-term monitoring is required.
The verification report should include a detailed description of the remedial work that took place. It should specify where removal or treatment of soil or groundwater has been completed and where verification samples have been obtained. The report should conclude as to whether the remedial work has been successful and if the site is suitable for its proposed end-use. Again, a checklist is included for submission with a verification report to the local authority.
The guidance concludes with a reminder that planning conditions for contamination can only be discharged once all of the necessary work has been completed to the satisfaction of the local planning authority.
We think that this document (available here) provides a straightforward guide for those who want to further their understanding on the process of brownfield site assessment. However, if you’d prefer something more visual, you might like to check out the infographic that we recently produced, which is available here.
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