A GUIDE TO INVESTIGATION OF PREVIOUSLY DEVELOPED LAND & BROWNFIELD SITES
The government has set a target that 60% of all new buildings should be built on previously developed land (brownfield sites), to relieve the pressure on demand for Greenfield sites. In some cases previous industrial activities may result in the land being affected by contaminants.
As part of the planning process, SBDC will need to be satisfied that the developer has performed an adequate assessment of the risks posed by any contaminants present and that any remedial measures are suitable so that no harm will be caused to end users.
It is the responsibility of the developer to perform a risk assessment of the site taking into consideration, previous use, geological and hydrological setting, together with the intended use.
Potential developers should be made aware of what is expected of them by way of decontamination and remedial works to be undertaken, when they develop land.
Managing land that may have contaminants present involves risk identification. An effectively managed site is less likely to be investigated by the Local Authority under Part IIA of the Environmental Protection Act 1990.
The councils Contamination Strategy is available for download, please click here to download the document (PDF 185.8KB).
To identify the risks, a phased investigation is necessary, this is likely to involve:
Phase I Desk Top Review
Phase II Intrusive Site Investigation
Phase III Remediation Statements & Validation Reports
A checklist has been included for your information, the list is not exhaustive and site reports will vary according to site-specific issues. SBDC are keen to provide helpful advice in parallel with its enforcement duties. An early response can speed the process and may resolve potential problems.
(a) Purpose and aims of study
(b) Site location and layout plans
(c) Appraisal of site history and previous uses of land surrounding the site
- Review of historical maps
(d) Assessment of environmental setting, to include:
- Geology, hydrogeology, hydrology
- Information on quarrying activity (if applicable)
- Information from Environment Agency on abstractions, pollution incidents, water quality classification, landfill sites, etc
- Information from SBDC on former landfill sites, private water supplies, contaminated land, pollution incidents, etc
Request for site search in writing only to Environmental Protection Team, Environmental Health, South Bedfordshire District Council, High Street North, Dunstable, LU6 1LF
(e) Assessment of current / proposed site use and surrounding land uses
(f) Review of any previous site contamination studies (desk-based or intrusive) or remediation works
(g) Initial risk assessment based on proposed development:
- Appraisal of actual and/or potential contaminant sources, pathways and receptors
- Conceptual site model (visual and written)
(h) Recommendations for intrusive contamination investigation (if necessary) to include target areas for more detailed investigation
PHASE II INTRUSIVE SITE INVESTIGATION
(a) Review of any previous site contamination studies (desk-based or intrusive) or remediation works
(b) Site investigation methodology:
- Methods of investigation
- Plan and justification showing exploration locations.
- Sampling and analytical strategies
(c) Results and findings of investigation:
- Ground conditions (soil, gas and water regimes, inc made ground)
- Discussion of soil/gas/water contamination (inc visual, olfactory, analytical and monitoring data)
(d) Conceptual site model (visual and written, changes from Phase 1 report)
(e) Risk assessment as a minimum, based on contaminant-pathway-receptor model. Should take account of severity of consequences and likelihood of occurrence.
- Justification of any risk assessment models used. A suitable quantitative risk assessment may be required
- Appropriate authorative and scientifically based guidelines shall be used.
(f) Recommendations for remediation justification should relate to site current and proposed end use, risk assessment findings, as well as technical and financial appraisal
(g) Recommendations for further investigation, if necessary
PHASE III REMEDIATION STATEMENTS & VALIDATION REPORTS
(a) Objectives of the remediation works
(b) Detailed outline of the works to be carried out, including:
- Description of ground conditions
- Type, form and scale of contamination to be remediated
- Remediation methodology, including remedial, protective or other works
- Site plans/drawings
- Phasing of works and approximate timescales
- Consents, agreements and licences.
(c) Site management procedures to protect site neighbours, environment and amenity during works, including where appropriate
- Health & safety procedures
- Dust, noise & odour controls
- Control of surface run-off
(d) Details of how the works will be validated to ensure the remediation objectives have been met, including details where appropriate on
- Sampling strategy
- Use of on-site observations, visual/olfactory evidence
- Chemical analysis/monitoring data
- Proposed clean-up standards (i.e. contaminant concentrations)
- Whether validation will be undertaken on a phased basis
(e) Include information as detailed in Remediation Statement, including details of who carried out the work
(f) Details and justification of any changes from original Remediation Statement
(g) Substantiating data should include where appropriate
- Laboratory and in situ test results
- Monitoring results for groundwater and gases
- Summary data plots and tables relating to clean-up criteria
- Plans showing treatment areas and details of any differences from original Remediation Statement
(h) Confirmation that remediation objectives have been met
Please note that these guides are produced to help you, they are not a definitive guide to the precise meaning of the Regulations.
