Unlocking the potential of brownfield land sustainably

There are many challenges and opportunities of redeveloping contaminated brownfield sites, shares Dan Matthews, director in our geoconsultancy team.

In an article first published in Ground Engineering Magazine, Dan highlights the importance of sustainable remediation, early site investigation and integrated design strategies:

The Netflix drama “Toxic Town” has brought the legacy of contamination from former industrial activities back into the public eye. In addition, increasing awareness and media interest in the emerging impact of per- and polyfluoroalkyl substance (PFAS) contamination – a group of man-made chemicals used in consumer products worldwide since the 1950s – is bringing this into sharper focus.

Previously, many local authorities and the Environment Agency made good progress in identifying and starting to address the legacy of land contamination through their responsibilities under Part2A of the Environmental Protection Act. However, cuts to public funding have meant that resources have been diverted elsewhere. These activities are now few and far between, with the onus placed on securing investigation and remediation through the planning process as sites come forward for development. Some brownfield land is being assessed and remediated by responsible landowners on a voluntary basis as part of managing their assets and the potential future liabilities associated with them, but there remain a large number of brownfield sites still to be investigated and addressed.

Nevertheless, the need for housing and the improvement of our towns and cities presents an opportunity to address this legacy and bring these brownfield sites back into use. The government’s drive to increase the pace of development, with a focus on brownfield sites and the potential introduction of Brownfield Passports is a positive step towards this goal.

The UK is well placed to drive this forward, with a great deal of important groundwork already completed. The Environment Agency’s guidance – soon to be adopted in a similar form by the Scottish Environment Protection Agency– is well established, and we have an industry of experienced professionals who have been addressing the legacy of contamination across the UK, particularly since the introduction of the Environmental Protection Act in 1990.

Importantly, the National Planning Policy Framework includes requirements for sites to be appropriately investigated and remediated so that they are suitable for the proposed end use and do not present an unacceptable risk to the environment. The processes are therefore in place to support an increase in sustainable brownfield development.

Developing brownfield sites can be complex and can lead to additional costs and programme delays if not approached appropriately. A sound understanding of ground conditions and soil functions is critical to sustainable and pragmatic design. Planning applications typically only require desk-based assessments, but there are significant advantages to undertaking intrusive site investigations early in the planning and design process. This enables a better understanding of ground conditions, which can positively influence and guide masterplanning decisions.

Depending on remediation requirements, extensive remediation and enabling works may be needed to unlock brownfield sites. The costs to investigate and remediate sites can be significant, so investment is required – whether from public funds and initiatives or through private finance. The construction industry needs certainty from the planning process to provide the confidence required to move such sites forward. Greater certainty that early investment in brownfield land will lead to planning approval will help build confidence among developers and investors.

Crucially, if we are to develop brownfield sites sustainably and create thriving communities, we need to consider other key aspects alongside remediation. These include climate-resilient surface water management and drainage design, improvements to biodiversity, and how we service developments with clean energy, active travel solutions and carbon-efficient design.

With the increasing urgency to deliver housing, there is a risk that contractors and developers may revert to disposing of contaminated and surplus soils to landfill as a quick and easy solution. This could lead to a significant rise in landfill use and a serious negative impact on the overall sustainability of construction across the UK. To counter this, it is important to prioritise material treatment, reuse strategies and the minimisation of excavation early in the design process.

Soil functions, material reuse, soil health and biodiversity are all interconnected and contribute to the low-carbon agenda. We must recognise how they interact as part of a single system and keep this in mind as we respond to the government’s housebuilding and development agenda and unlock the potential of brownfield sites.